50+:1 15m sailplanes [Archive]

Chris OCallaghan

December 22nd 03, 07:21 PM

It's been a few years, but if memory serves Gerhard said that the 27
wing could manage a Finesse (best L/D) of 100, that is, if he didn't
have to hang a fuselage off of it. However, most glider pilots like to
fly their aircraft in the first person, so he compromised and got a
Finesse around 46. The Diana, on the other hand, took the road less
travelled by and decided that pilot comfort (or in my case, presence)
were not critical marketing factors. Based on that philosophy, I
wouldn't doubt that a determined engineer could achieve a Finesse of
50+ for a 15 meter glider. However, we've learned that best L/D is a
poor means of judging sailplane performance. It is the flatness of the
drag curves on both sides of the intersection that really determine
the worth of your glider. A polar free of a low speed bucket and
relatively flat increase of sink with speed make a great glider. Might
the poles have found a new trick? A more stable high aspect ratio
airfoil that needs less tail? A better fuselage/wing transition?
Improved laminar control? Perhaps.

Paul T > wrote in message >...
> 'DuckHawk 15m racer announced at 2003 SHA Western Workshop.
> 53:1glide ratio VNE 200 kts' -from Winward Performance
> - anyone got anymore details?
>
> 'SZD-56-2, Diana 2: Newest 15-meter Sailplane.The technologically
> advanced SZD-56-2 Diana 2 will soar on new wings next
> summer. Bogumil Beres, chief design engineer of the
> Diana and owner of Biuro Projektowe 'B' Bogumil Beres,
> recently announced the design project of a breakthrough
> Diana 2, featuring a curved wing platform with a continuously
> varying airfoil and high-performance winglets. The
> original Diana fuselage will be retained, but with
> a lower drag fuselage-wing junction. The wing loading
> range will be 6.08 - 11.7 psf. Most remarkably, the
> Diana 2 will break the long-standing 15-meter glide
> ratio barrier of 50/1 with room to spare: forecast
> performance includes a max L/D of 52/1. The prototype
> Diana 2 wings will fly next August. Diana 2's will
> be delivered in the Spring of 2005.'
>
> Have the Germans got something to worry about?

Robert Danewid

December 23rd 03, 11:56 AM

There were 2 SZD56 flying in the worlds in Sweden in 1993. They
performed nice but not astonishing. One of them even had a minor midair.

A year later or so we had one (modified) exhibited at the Annual Swedish
Cliding Conference, and as Chris writes, the cockpit were not built for
nice looking guys from the West, but supposedly for thin, starving
pilots from the eastblock...... (now that has thank God changed!)

Moffat once wrote: there is no substitute for span! If you want 50+ go
for an 18m or larger ship, if you want nice handling, easy rigging etc,
it is easy to trade in som finesse-point to achieve that in a 15m glider!

Robert
H304

Chris OCallaghan wrote:
> It's been a few years, but if memory serves Gerhard said that the 27
> wing could manage a Finesse (best L/D) of 100, that is, if he didn't
> have to hang a fuselage off of it. However, most glider pilots like to
> fly their aircraft in the first person, so he compromised and got a
> Finesse around 46. The Diana, on the other hand, took the road less
> travelled by and decided that pilot comfort (or in my case, presence)
> were not critical marketing factors. Based on that philosophy, I
> wouldn't doubt that a determined engineer could achieve a Finesse of
> 50+ for a 15 meter glider. However, we've learned that best L/D is a
> poor means of judging sailplane performance. It is the flatness of the
> drag curves on both sides of the intersection that really determine
> the worth of your glider. A polar free of a low speed bucket and
> relatively flat increase of sink with speed make a great glider. Might
> the poles have found a new trick? A more stable high aspect ratio
> airfoil that needs less tail? A better fuselage/wing transition?
> Improved laminar control? Perhaps.
>
>
>
>
>
> Paul T > wrote in message >...
>
>>'DuckHawk 15m racer announced at 2003 SHA Western Workshop.
>>53:1glide ratio VNE 200 kts' -from Winward Performance
>>- anyone got anymore details?
>>
>>'SZD-56-2, Diana 2: Newest 15-meter Sailplane.The technologically
>>advanced SZD-56-2 Diana 2 will soar on new wings next
>>summer. Bogumil Beres, chief design engineer of the
>>Diana and owner of Biuro Projektowe 'B' Bogumil Beres,
>>recently announced the design project of a breakthrough
>>Diana 2, featuring a curved wing platform with a continuously
>>varying airfoil and high-performance winglets. The
>>original Diana fuselage will be retained, but with
>>a lower drag fuselage-wing junction. The wing loading
>>range will be 6.08 - 11.7 psf. Most remarkably, the
>>Diana 2 will break the long-standing 15-meter glide
>>ratio barrier of 50/1 with room to spare: forecast
>>performance includes a max L/D of 52/1. The prototype
>>Diana 2 wings will fly next August. Diana 2's will
>>be delivered in the Spring of 2005.'
>>
>>Have the Germans got something to worry about?

Bob Johnson

December 23rd 03, 05:00 PM

Just to keep stuff straight, while Mr. Moffat has certainly expessed
from time to time his fondness for span, I believe "there is no
substitute for span" quote comes from Michael Bird ("Platypus") who used
to "tinsfos" us quite regularly in S & G (Brit mag) from across the pond
....

Of course I could be wrong ..

BJ

Robert Danewid wrote:
>
> There were 2 SZD56 flying in the worlds in Sweden in 1993. They
> performed nice but not astonishing. One of them even had a minor midair.
>
> A year later or so we had one (modified) exhibited at the Annual Swedish
> Cliding Conference, and as Chris writes, the cockpit were not built for
> nice looking guys from the West, but supposedly for thin, starving
> pilots from the eastblock...... (now that has thank God changed!)
>
> Moffat once wrote: there is no substitute for span! If you want 50+ go
> for an 18m or larger ship, if you want nice handling, easy rigging etc,
> it is easy to trade in som finesse-point to achieve that in a 15m glider!
>
> Robert
> H304
>
> Chris OCallaghan wrote:
> > It's been a few years, but if memory serves Gerhard said that the 27
> > wing could manage a Finesse (best L/D) of 100, that is, if he didn't
> > have to hang a fuselage off of it. However, most glider pilots like to
> > fly their aircraft in the first person, so he compromised and got a
> > Finesse around 46. The Diana, on the other hand, took the road less
> > travelled by and decided that pilot comfort (or in my case, presence)
> > were not critical marketing factors. Based on that philosophy, I
> > wouldn't doubt that a determined engineer could achieve a Finesse of
> > 50+ for a 15 meter glider. However, we've learned that best L/D is a
> > poor means of judging sailplane performance. It is the flatness of the
> > drag curves on both sides of the intersection that really determine
> > the worth of your glider. A polar free of a low speed bucket and
> > relatively flat increase of sink with speed make a great glider. Might
> > the poles have found a new trick? A more stable high aspect ratio
> > airfoil that needs less tail? A better fuselage/wing transition?
> > Improved laminar control? Perhaps.
> >
> >
> >
> >
> >
> > Paul T > wrote in message >...
> >
> >>'DuckHawk 15m racer announced at 2003 SHA Western Workshop.
> >>53:1glide ratio VNE 200 kts' -from Winward Performance
> >>- anyone got anymore details?
> >>
> >>'SZD-56-2, Diana 2: Newest 15-meter Sailplane.The technologically
> >>advanced SZD-56-2 Diana 2 will soar on new wings next
> >>summer. Bogumil Beres, chief design engineer of the
> >>Diana and owner of Biuro Projektowe 'B' Bogumil Beres,
> >>recently announced the design project of a breakthrough
> >>Diana 2, featuring a curved wing platform with a continuously
> >>varying airfoil and high-performance winglets. The
> >>original Diana fuselage will be retained, but with
> >>a lower drag fuselage-wing junction. The wing loading
> >>range will be 6.08 - 11.7 psf. Most remarkably, the
> >>Diana 2 will break the long-standing 15-meter glide
> >>ratio barrier of 50/1 with room to spare: forecast
> >>performance includes a max L/D of 52/1. The prototype
> >>Diana 2 wings will fly next August. Diana 2's will
> >>be delivered in the Spring of 2005.'
> >>
> >>Have the Germans got something to worry about?

Ian Strachan

December 23rd 03, 09:05 PM

In article >, Bob Johnson
> writes

>Just to keep stuff straight, while Mr. Moffat has certainly expessed
>from time to time his fondness for span, I believe "there is no
>substitute for span" quote comes from Michael Bird ("Platypus")

I do not think that Plat would claim credit for this saying which,
regarding straight performance, has been extant in gliding since I
started in the 1950s.

It refers to the "easiest way to increase performance" (max L/D I
suppose), contrasting the relative simplicity of adding span compared to
the complexities of adding flaps, new airfoil sections, new
configurations, etc.

In my own case I remember the Grunau (about 13m I think), good in a
thermal but not in a glide, a sort of ancient PW-5. After the Grunau, I
progressed through the 15m Meise (well the UK Olympia version anyway) to
the Skylark 2 (laminar 15m) to the Skylark 3 & 4 (18m) and finally
through various syndicates from 15 to 18m to the Nimbus series, starting
at 22m and now 26 in the Nimbus 4DM, twice the span of the dear old
Grunau.

As far as I am concerned, "there is no substitute for span". In UK
soaring conditions, anyway, if you wish to avoid landing "aux vaches".
Our vaches may not be very vicious but our roads (for retrieving) are
........

--
Ian Strachan
Lasham Gliding Centre
UK South

Robert Danewid

December 24th 03, 12:03 AM

Never mind

It is till a good quote

(I still think it was Moffat back in the 70s)

Robert

Bob Johnson wrote:
> Just to keep stuff straight, while Mr. Moffat has certainly expessed
> from time to time his fondness for span, I believe "there is no
> substitute for span" quote comes from Michael Bird ("Platypus") who used
> to "tinsfos" us quite regularly in S & G (Brit mag) from across the pond
> ...
>
> Of course I could be wrong ..
>
> BJ
>
>
> Robert Danewid wrote:
>
>>There were 2 SZD56 flying in the worlds in Sweden in 1993. They
>>performed nice but not astonishing. One of them even had a minor midair.
>>
>>A year later or so we had one (modified) exhibited at the Annual Swedish
>>Cliding Conference, and as Chris writes, the cockpit were not built for
>>nice looking guys from the West, but supposedly for thin, starving
>>pilots from the eastblock...... (now that has thank God changed!)
>>
>>Moffat once wrote: there is no substitute for span! If you want 50+ go
>>for an 18m or larger ship, if you want nice handling, easy rigging etc,
>>it is easy to trade in som finesse-point to achieve that in a 15m glider!
>>
>>Robert
>>H304
>>
>>Chris OCallaghan wrote:
>>
>>>It's been a few years, but if memory serves Gerhard said that the 27
>>>wing could manage a Finesse (best L/D) of 100, that is, if he didn't
>>>have to hang a fuselage off of it. However, most glider pilots like to
>>>fly their aircraft in the first person, so he compromised and got a
>>>Finesse around 46. The Diana, on the other hand, took the road less
>>>travelled by and decided that pilot comfort (or in my case, presence)
>>>were not critical marketing factors. Based on that philosophy, I
>>>wouldn't doubt that a determined engineer could achieve a Finesse of
>>>50+ for a 15 meter glider. However, we've learned that best L/D is a
>>>poor means of judging sailplane performance. It is the flatness of the
>>>drag curves on both sides of the intersection that really determine
>>>the worth of your glider. A polar free of a low speed bucket and
>>>relatively flat increase of sink with speed make a great glider. Might
>>>the poles have found a new trick? A more stable high aspect ratio
>>>airfoil that needs less tail? A better fuselage/wing transition?
>>>Improved laminar control? Perhaps.
>>>
>>>
>>>
>>>
>>>
>>>Paul T > wrote in message >...
>>>
>>>
>>>>'DuckHawk 15m racer announced at 2003 SHA Western Workshop.
>>>>53:1glide ratio VNE 200 kts' -from Winward Performance
>>>>- anyone got anymore details?
>>>>
>>>>'SZD-56-2, Diana 2: Newest 15-meter Sailplane.The technologically
>>>>advanced SZD-56-2 Diana 2 will soar on new wings next
>>>>summer. Bogumil Beres, chief design engineer of the
>>>>Diana and owner of Biuro Projektowe 'B' Bogumil Beres,
>>>>recently announced the design project of a breakthrough
>>>>Diana 2, featuring a curved wing platform with a continuously
>>>>varying airfoil and high-performance winglets. The
>>>>original Diana fuselage will be retained, but with
>>>>a lower drag fuselage-wing junction. The wing loading
>>>>range will be 6.08 - 11.7 psf. Most remarkably, the
>>>>Diana 2 will break the long-standing 15-meter glide
>>>>ratio barrier of 50/1 with room to spare: forecast
>>>>performance includes a max L/D of 52/1. The prototype
>>>>Diana 2 wings will fly next August. Diana 2's will
>>>>be delivered in the Spring of 2005.'
>>>>
>>>>Have the Germans got something to worry about?

Robert Danewid

December 24th 03, 12:07 AM

Ian, I thought your "aux vaches" was the M in Nimbus4DM......

Robert

Ian Strachan wrote:

> In article >, Bob Johnson
> > writes
>
>> Just to keep stuff straight, while Mr. Moffat has certainly expessed
>> from time to time his fondness for span, I believe "there is no
>> substitute for span" quote comes from Michael Bird ("Platypus")
>
>
> I do not think that Plat would claim credit for this saying which,
> regarding straight performance, has been extant in gliding since I
> started in the 1950s.
>
> It refers to the "easiest way to increase performance" (max L/D I
> suppose), contrasting the relative simplicity of adding span compared to
> the complexities of adding flaps, new airfoil sections, new
> configurations, etc.
>
> In my own case I remember the Grunau (about 13m I think), good in a
> thermal but not in a glide, a sort of ancient PW-5. After the Grunau, I
> progressed through the 15m Meise (well the UK Olympia version anyway) to
> the Skylark 2 (laminar 15m) to the Skylark 3 & 4 (18m) and finally
> through various syndicates from 15 to 18m to the Nimbus series, starting
> at 22m and now 26 in the Nimbus 4DM, twice the span of the dear old Grunau.
>
> As far as I am concerned, "there is no substitute for span". In UK
> soaring conditions, anyway, if you wish to avoid landing "aux vaches".
> Our vaches may not be very vicious but our roads (for retrieving) are
> .......
>

wsburhen

December 24th 03, 05:20 AM

The quote that I've seen attributed to Plat concerning tinsfos is
something to the effect of:
"There is a substitute for span, it's called skill, but you can buy
span"

JJ Sinclair

December 24th 03, 02:18 PM

>"There is a substitute for span, it's called skill, but you can buy
>span"

OK, it's 7:00 PM, the sky has been completely overcast for hours, you have
5000 feet and your looking at a 50 mile final glide. Now SKILL your way home.

A very mery Christmas to all my RAS buddies.
JJ Sinclair

Noël De Corte

December 24th 03, 05:06 PM

JJ Sinclair wrote:

> I own an honest to god, 53:1, 15 meter ship. I'm not kidding, on several
> occasions the GPS trace shows I am making 100 foot per statute mile. The only
> problem is, when I measure the wings, the tape reads 86 feet (ASH-25)
> JJ Sinclair

With a back wind of 75 km/h this is no problem for a 15m ship.

Noël

George William Peter Reinhart

December 24th 03, 05:22 PM

JJ,
It is clear that, in spite of your vast knowledge of all things connected
with sailplane repair, you are using the wrong tool for the job.
When I was in the sailmaking business we had a specialized tool which we
shop fabricated for just this type of critical work. It's called a jib snap
spacing tape and you make it from half inch or inch wide batten pocket
elastic marked with indelible markers in suitable increments. In your case
I would advise 1 meter marks to make it easy.
I bet if you would use the proper tool, as suggested here, and correctly
apply it, you'll find your 53:1 glider is pretty close to the desired 15
meter span.
Here's wishing you and all of the R.A.S. community health , happiness, and
prosperity for the holiday season and the coming year.
Cheers!, Pete

JJ Sinclair > wrote in article
>...
> I own an honest to god, 53:1, 15 meter ship. I'm not kidding, on several
> occasions the GPS trace shows I am making 100 foot per statute mile. The
only
> problem is, when I measure the wings, the tape reads 86 feet (ASH-25)
> JJ Sinclair
>

Robert Danewid

December 24th 03, 09:53 PM

JJ, negative thinking - use the force!

Robert

JJ Sinclair wrote:
>>"There is a substitute for span, it's called skill, but you can buy
>>span"
>
>
> OK, it's 7:00 PM, the sky has been completely overcast for hours, you have
> 5000 feet and your looking at a 50 mile final glide. Now SKILL your way home.
>
> A very mery Christmas to all my RAS buddies.
> JJ Sinclair

Paul T

December 25th 03, 09:33 AM

Here's the figures on the American DuckHawk (got to
be one of the most awful names for a sailplane) from
the promo sheet.

Windward Performance LLC takes its advanced technology
to the racing class.

Specifications
Empty Weight 300 LBS
Gross Weight 900 LBS
Wing Span 49.17 FT
Wing Area 74.93 FT^2
Aspect Ratio 32.2:1
Length 20.6 FT
Horizontal Span 6.8 FT
Vertical Height 4.5 FT

Structural Limits
+11.0 / -9.0 g’s
Va, Vb = 165 KTS
Vne = 200 KTS

Performance
At 500 LBS, 6.7 Lbs/FT^2
Best Glide 50:1 at 50 KTS
Min Sink 94 FPM at 40 KTS
Stall Speed 35 KTS

At 900 LBS, 12.0 Lbs/FT^2
Best Glide 52:1 at 67 KTS
Min Sink 122 FPM at 57 KTS
Stall Speed 47 KTS
(data for 900 LBS, 12 PSF)

Airfoils
Inboard 12.7 % t/c
Outboard 10.2 % t/c

The DuckHawk has the broadest wing loading range available,
the highest maneuvering and redline speeds, and the
lowest inertias for snappy handling. The lower flying
mass within the 15m span constraint gives an induced
drag advantage of 49% at 500 LBS and 33% at 900 LBS
(span loading squared) compared to the competition

Time will tell - my money is on the Diana 2 which is
a development of the SZD-56-1 Diana. (Whose cockpit
is bigger than a Ventus a!). Incedently at Leszno they
were also talking about an 18m version and 22m Open
class version.

Eric Greenwell

December 25th 03, 10:42 PM

JJ Sinclair wrote:
>>"There is a substitute for span, it's called skill, but you can buy
>>span"
>
>
> OK, it's 7:00 PM, the sky has been completely overcast for hours, you have
> 5000 feet and your looking at a 50 mile final glide. Now SKILL your way home.

You don't grasp the concept, JJ: with skill, the pilot is 50 miles out
at 6 pm, not 7 pm, and gets home just before all the lift dies.

Since I can't buy skill either, I bought a motor.

Steve Hopkins

December 25th 03, 10:58 PM

I seem to remember a wonderful letter in Sailplane and Gliding in which
the writer noted that, when he first started gliding in his twenties,
average glider LD ratios were around 1:20's. In his thirties, this rose
to 1;30's and, at the time of writing, in his forties, 1:40's. He was
looking forward to his 100th birthday! May be new materials, better
design will prove a substitute for span. The one thing that there will
never be a substitute for is Money. Anyone who disagrees may care to
explain the absence of K8's from the various handicapped comps.

-----Original Message-----
From: Glider Pilot Network ]
Sent: Wednesday, December 24, 2003 10:10 PM
To: Steve Hopkins
Subject: [r.a.s] Re: 50+:1 15m sailplanes

------------------------------------------------------------
Newsgroup: rec.aviation.soaring
Subject: Re: 50+:1 15m sailplanes
Author: Robert Danewid >
Date/Time: 22:00 24 December 2003
------------------------------------------------------------
JJ, negative thinking - use the force!

Robert

JJ Sinclair wrote:
>>"There is a substitute for span, it's called skill, but you can buy
>>span"
>
>
> OK, it's 7:00 PM, the sky has been completely overcast for hours, you
have
> 5000 feet and your looking at a 50 mile final glide. Now SKILL your
> way
home.
>
> A very mery Christmas to all my RAS buddies.
> JJ Sinclair

------------------------------------------------------------

Gerhard Wesp

December 26th 03, 11:02 AM

Ian Strachan > wrote:
> Our vaches may not be very vicious but our roads (for retrieving) are

But didn't the ``vaches folles'' (=mad cow) start out in the UK??

SCNR ;-)
-Gerhard

Ian Strachan

December 26th 03, 11:41 AM

In article >, Eric Greenwell
> writes
>JJ Sinclair wrote:
>>>"There is a substitute for span, it's called skill, but you can buy
>>>span"
>> OK, it's 7:00 PM, the sky has been completely overcast for hours,
>>you have
>> 5000 feet and your looking at a 50 mile final glide. Now SKILL your way home.
>
>You don't grasp the concept, JJ: with skill, the pilot is 50 miles out
>at 6 pm, not 7 pm, and gets home just before all the lift dies.
>
>Since I can't buy skill either, I bought a motor.

Even better, a motor AND good L/D. Gap-crossing can be needed any time,
not necessarily after 6 PM !

--
Ian Strachan
Gap Crossing Country (UK)

JJ Sinclair

December 26th 03, 02:54 PM

Eric wrote>>>>>>>>>>>>>>>>>
>Since I can't buy skill either, I bought a motor.
>

Now, Now, Eric we don't want to start that *motor* argument again, do we?
JJ Sinclair

JJ Sinclair

December 26th 03, 03:01 PM

Iam wrote>>>>>>>>>>>>>>>>>>>>.>
>Even better, a motor AND good L/D. Gap-crossing can be needed any time,
>not necessarily after 6 PM !
>

Now, Now, Ian we don't want to start that *motor glider* vs *pure glider*
discussion again, do we?

JJ Sinclair

Ian Strachan

December 26th 03, 08:59 PM

In article >, JJ Sinclair
> writes
>Iam wrote>>>>>>>>>>>>>>>>>>>>.>
>>Even better, a motor AND good L/D. Gap-crossing can be needed any time,
>>not necessarily after 6 PM !
>>
>
>Now, Now, Ian we don't want to start that *motor glider* vs *pure glider*
>discussion again, do we?

I meant gap crossing by L/D, not by motor, as I am sure you knew!

I only use the motor to avoid landing out, and that very rarely. This
year, not at all other than self-launch.

--
Ian Strachan

Bentworth Hall West
Tel: +44 1420 564 195 Bentworth, Alton
Fax: +44 1420 563 140 Hampshire GU34 5LA, ENGLAND

Eric Greenwell

December 26th 03, 09:31 PM

JJ Sinclair wrote:

> Eric wrote>>>>>>>>>>>>>>>>>
>
>>Since I can't buy skill either, I bought a motor.
>>
>
>
> Now, Now, Eric we don't want to start that *motor* argument again, do we?
> JJ Sinclair

That was a *contest* argument, I think!

And lest someone not understand the joking going on here, it's worth
noting that span, motors, and skill aren't mutually exclusive, as Klaus
Ohlmann and others flying in Argentina have shown them to be a potent
combination. Regardless of our individual skills, we all face the
challenge of finding that "sweet spot" combination of glider attributes
(performance, handling, cost, span, motor, competitiveness, etc.) that
will give us the most enjoyment for our money. The glider we end up with
affects the social aspects (who we fly with, when and where we fly), and
the social aspects also affect the glider we choose.
--
-----
change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

BTIZ

December 29th 03, 02:48 AM

I don't see it on their web page..

BT

"Paul T" > wrote in message
...
> Here's the figures on the American DuckHawk (got to
> be one of the most awful names for a sailplane) from
> the promo sheet.
>
> Windward Performance LLC takes its advanced technology
> to the racing class.
>
>
> Specifications
> Empty Weight 300 LBS
> Gross Weight 900 LBS
> Wing Span 49.17 FT
> Wing Area 74.93 FT^2
> Aspect Ratio 32.2:1
> Length 20.6 FT
> Horizontal Span 6.8 FT
> Vertical Height 4.5 FT
>
> Structural Limits
> +11.0 / -9.0 g's
> Va, Vb = 165 KTS
> Vne = 200 KTS
>
> Performance
> At 500 LBS, 6.7 Lbs/FT^2
> Best Glide 50:1 at 50 KTS
> Min Sink 94 FPM at 40 KTS
> Stall Speed 35 KTS
>
> At 900 LBS, 12.0 Lbs/FT^2
> Best Glide 52:1 at 67 KTS
> Min Sink 122 FPM at 57 KTS
> Stall Speed 47 KTS
> (data for 900 LBS, 12 PSF)
>
> Airfoils
> Inboard 12.7 % t/c
> Outboard 10.2 % t/c
>
>
> The DuckHawk has the broadest wing loading range available,
> the highest maneuvering and redline speeds, and the
> lowest inertias for snappy handling. The lower flying
> mass within the 15m span constraint gives an induced
> drag advantage of 49% at 500 LBS and 33% at 900 LBS
> (span loading squared) compared to the competition
>
>
> Time will tell - my money is on the Diana 2 which is
> a development of the SZD-56-1 Diana. (Whose cockpit
> is bigger than a Ventus a!). Incedently at Leszno they
> were also talking about an 18m version and 22m Open
> class version.
>
>
>
>

Eric Greenwell

December 29th 03, 03:36 AM

The info appears to be from a handout at the Sailplane Homebuilders
Association's Western Meeting at Tehachapi, CA, in September 2003. I
can't find my copy of the handout, and the website only mentions the
DuckHawk (Peregrine falcon, but maybe that name was taken, or more
likely, to match with the SparrowHawk now being produced).

BTIZ wrote:
> I don't see it on their web page..
>
> BT
>
> "Paul T" > wrote in message
> ...
>
>>Here's the figures on the American DuckHawk (got to
>>be one of the most awful names for a sailplane) from
>>the promo sheet.
>>
>>Windward Performance LLC takes its advanced technology
>>to the racing class.
>>
>>
>>Specifications
>>Empty Weight 300 LBS
>>Gross Weight 900 LBS
>>Wing Span 49.17 FT
>>Wing Area 74.93 FT^2
>>Aspect Ratio 32.2:1
>>Length 20.6 FT
>>Horizontal Span 6.8 FT
>>Vertical Height 4.5 FT
>>
>>Structural Limits
>>+11.0 / -9.0 g's
>>Va, Vb = 165 KTS
>>Vne = 200 KTS
>>
>>Performance
>>At 500 LBS, 6.7 Lbs/FT^2
>>Best Glide 50:1 at 50 KTS
>>Min Sink 94 FPM at 40 KTS
>>Stall Speed 35 KTS
>>
>>At 900 LBS, 12.0 Lbs/FT^2
>>Best Glide 52:1 at 67 KTS
>>Min Sink 122 FPM at 57 KTS
>>Stall Speed 47 KTS
>>(data for 900 LBS, 12 PSF)
>>
>>Airfoils
>>Inboard 12.7 % t/c
>>Outboard 10.2 % t/c
>>
>>
>>The DuckHawk has the broadest wing loading range available,
>>the highest maneuvering and redline speeds, and the
>>lowest inertias for snappy handling. The lower flying
>>mass within the 15m span constraint gives an induced
>>drag advantage of 49% at 500 LBS and 33% at 900 LBS
>>(span loading squared) compared to the competition
>>
>>
>>Time will tell - my money is on the Diana 2 which is
>>a development of the SZD-56-1 Diana. (Whose cockpit
>>is bigger than a Ventus a!). Incedently at Leszno they
>>were also talking about an 18m version and 22m Open
>>class version.
>>
>>
>>
>>
>
>
>

--
-----
change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

GMC

December 29th 03, 05:51 PM

Wil Schuemann achieved 50:1 with his modified ASW-12 (wings modified
and cut down to 15 m span). Very clear clean sink rate data on a very
good calm day with as little airmass movement as one could hope for.
This was in the early 80's with an aircraft that was old then.

Bob Kuykendall

December 30th 03, 01:25 AM

Earlier, Greg Cole ) wrote:

> ...Very clear clean sink rate data
> on a very good calm day with as
> little airmass movement as one
> could hope for.

I'd like to see that data. Is it available online?

Thanks, and best regards to all

Bob K.
http://www.hpaircraft.com

Swiftel

January 8th 04, 11:36 AM

"Ian Strachan" > wrote in message
...
> In article >, Bob Johnson
> > writes
..........
> It refers to the "easiest way to increase performance" (max L/D I
> suppose), contrasting the relative simplicity of adding span compared to
> the complexities of adding flaps, new airfoil sections, new
> configurations, etc.
........

ahhh - I like this remark Ian,
wouldn't it have been very wise if the IGC would have had this insight
before they created the 15m class.
Isn't it true that already then, several manufacturers proposed 18m wingspan
instaed of the PIKs 15m?
Or can you tell us why the racing class really got 15 instead of 18m
wingspan?
Chris

Swiftel

January 8th 04, 11:48 AM

I hope that they will give the wing a bit more AOA related to the
cockpit/fuselage.
The Dianas I have seen always had bad visibility in the landing approach and
in
high speed the tail always hang a bit low in the airstream.
One of the factory guys from Poland told me in Borlaenge, that the
performance
could be increased by fixing that problem, but these days they had no money
to do
so.
The design shows some clever features, but I heard German designers having
some
doubts if the glider really would pass all JAR requirements.
CHo

"Paul T" > wrote in message
...
> Here's the figures on the American DuckHawk (got to
> be one of the most awful names for a sailplane) from
> the promo sheet.
>
> Windward Performance LLC takes its advanced technology
> to the racing class.
>
>
> Specifications
> Empty Weight 300 LBS
> Gross Weight 900 LBS
> Wing Span 49.17 FT
> Wing Area 74.93 FT^2
> Aspect Ratio 32.2:1
> Length 20.6 FT
> Horizontal Span 6.8 FT
> Vertical Height 4.5 FT
>
> Structural Limits
> +11.0 / -9.0 g's
> Va, Vb = 165 KTS
> Vne = 200 KTS
>
> Performance
> At 500 LBS, 6.7 Lbs/FT^2
> Best Glide 50:1 at 50 KTS
> Min Sink 94 FPM at 40 KTS
> Stall Speed 35 KTS
>
> At 900 LBS, 12.0 Lbs/FT^2
> Best Glide 52:1 at 67 KTS
> Min Sink 122 FPM at 57 KTS
> Stall Speed 47 KTS
> (data for 900 LBS, 12 PSF)
>
> Airfoils
> Inboard 12.7 % t/c
> Outboard 10.2 % t/c
>
>
> The DuckHawk has the broadest wing loading range available,
> the highest maneuvering and redline speeds, and the
> lowest inertias for snappy handling. The lower flying
> mass within the 15m span constraint gives an induced
> drag advantage of 49% at 500 LBS and 33% at 900 LBS
> (span loading squared) compared to the competition
>
>
> Time will tell - my money is on the Diana 2 which is
> a development of the SZD-56-1 Diana. (Whose cockpit
> is bigger than a Ventus a!). Incedently at Leszno they
> were also talking about an 18m version and 22m Open
> class version.
>
>
>
>

Ian Strachan

January 8th 04, 02:39 PM

In article >, Swiftel
> writes
>"Ian Strachan" > wrote in message
...
>> In article >, Bob Johnson
>> > writes
>.........
>> It refers to the "easiest way to increase performance" (max L/D I
>> suppose), contrasting the relative simplicity of adding span compared to
>> the complexities of adding flaps, new airfoil sections, new
>> configurations, etc.
>.......
>
>ahhh - I like this remark Ian,
>wouldn't it have been very wise if the IGC would have had this insight
>before they created the 15m class.
>Isn't it true that already then, several manufacturers proposed 18m wingspan
>instaed of the PIKs 15m?

No, but some of the German manufacturers proposed 16 m, which was so
close to the 15m flapped ships already being built (like the Pik 15)
that IGC decided to stick with 15m.

From memory the date was 1974 or so, when I was the UK delegate to IGC.
It was actually a BGA proposal to IGC that the old standard class rules
(under which the K6 was designed) be left alone, and the new class
should only be span-limited.

It is interesting that when Gerhard Weibal lectured at the BGA weekend
about 5 years ago, he naturally concentrated on huge-span sailplanes. I
therefore asked him in the question period what he considered the most
"cost-effective span". I expected him to say about 20 or 22 metres but
his reply was 17. Pretty close to the 16m I mentioned above, and
fortunately also to 18m which is now a separate IGC class and is
particularly suited to bearing the extra weight of a motor (whereas 15m
is a tad small for a self-launcher in a weak-thermal country).

>Or can you tell us why the racing class really got 15 instead of 18m
>wingspan?

I have written up my perspective on this for Sailplane and Gliding and
it may be published shortly. But basically as above. 18m was never
discussed by IGC in 1974 although this span was used in older wooden
designs such as the Skylark 3 and 4, etc.

--
Ian Strachan

Bentworth Hall West
Tel: +44 1420 564 195 Bentworth, Alton
Fax: +44 1420 563 140 Hampshire GU34 5LA, ENGLAND

Bill Daniels

January 8th 04, 03:38 PM

"Ian Strachan" > wrote in message
...
> In article >, Swiftel

Snip-----

> It is interesting that when Gerhard Weibal lectured at the BGA weekend
> about 5 years ago, he naturally concentrated on huge-span sailplanes. I
> therefore asked him in the question period what he considered the most
> "cost-effective span". I expected him to say about 20 or 22 metres but
> his reply was 17. Pretty close to the 16m I mentioned above, and
> fortunately also to 18m which is now a separate IGC class and is
> particularly suited to bearing the extra weight of a motor (whereas 15m
> is a tad small for a self-launcher in a weak-thermal country).

Snip-----
>

> Ian Strachan
>
> Bentworth Hall West
> Tel: +44 1420 564 195 Bentworth, Alton
> Fax: +44 1420 563 140 Hampshire GU34 5LA, ENGLAND
>

Interesting.

I recall a technical discussion a long time ago asking whether there was a
"natural best wingspan" imposed by the nature of soaring weather. The
question was this: "Ignoring competition classes, is there a single best
wingspan that is suited for the widest range of soaring conditions? The
answers converged around 18 meters. Larger spans were considered too slow
in strong conditions and smaller spans suffered in weak conditions. It's
interesting that the "most cost effective wingspan" is about the same.

This makes me wonder if eventually the 18 meter class will become dominant.
It also makes me wonder if the selection of 15 meters for the two most
popular classes was an error.

Bill Daniels

Eric Greenwell

January 8th 04, 11:59 PM

Bill Daniels wrote:

> I recall a technical discussion a long time ago asking whether there was a
> "natural best wingspan" imposed by the nature of soaring weather. The
> question was this: "Ignoring competition classes, is there a single best
> wingspan that is suited for the widest range of soaring conditions? The
> answers converged around 18 meters. Larger spans were considered too slow
> in strong conditions and smaller spans suffered in weak conditions. It's
> interesting that the "most cost effective wingspan" is about the same.
>
> This makes me wonder if eventually the 18 meter class will become dominant.
> It also makes me wonder if the selection of 15 meters for the two most
> popular classes was an error.

Here's my recollection of the genesis of the 15 meter class. Real
historians please fill in the gaps and correct errors.

In the beginning, there was only One class, and it became Huge and
Expensive, so the World Gliding Body (IGC?) made the Standard Class in
1960. It was Small and therefore Cheap, and it's Leader was the Ka-6. It
was Wood and it was Good.

But then, Dick Schreder rose up and Said, "Spoilers are a False god",
and he Made a Standard Slass glider with Flaps, and it was Better.
Better enough, that the World Gliding Body became concerned, and there
was also Pressure from Libelle H301 owners, so that a New class was born
in 1974 (or thereabouts): the 15 Meter class.

And it was Very successful, and spawned Many designs, and Thousands were
built, and the Contests were full, and it was Good. But then came Carbon
fiber, and new airfoils, and Pilots that knew nothing of Wood, and they
said "the World Gliding Body made a Mistake!" And they were Right..

Whoa! Not so fast. Back then 18 meter wasn't so easy to do. The choices
are different now, and it's a mistake to revisit the decision as if the
materials and aerodynamics we have now were available then, and as if
the pilots would accept the same trade-offs for cost and size that they
are willing to do now.

I think the 18 meter class has been driven by motorglider considerations
much more than any natural "sweet spot" in performance/$. And frankly,
to even claim that 18 meters is the "sweet spot" is a subjective
judgment. Lot's of people prefer smaller gliders, and many prefer bigger
gliders; for many people, it's the cost, not the L:D/$, that counts;
most people, I believe, don't fly in a wide range of conditions, but fly
during the heart of the day and don't visit locations that vary much.

--
-----
change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

Bill Daniels

January 9th 04, 12:57 AM

"Eric Greenwell" > wrote in message
...
> Bill Daniels wrote:
>
Snip--(A pretty good history)

> Whoa! Not so fast. Back then 18 meter wasn't so easy to do. The choices
> are different now, and it's a mistake to revisit the decision as if the
> materials and aerodynamics we have now were available then, and as if
> the pilots would accept the same trade-offs for cost and size that they
> are willing to do now.
>
> I think the 18 meter class has been driven by motorglider considerations
> much more than any natural "sweet spot" in performance/$. And frankly,
> to even claim that 18 meters is the "sweet spot" is a subjective
> judgment. Lot's of people prefer smaller gliders, and many prefer bigger
> gliders; for many people, it's the cost, not the L:D/$, that counts;
> most people, I believe, don't fly in a wide range of conditions, but fly
> during the heart of the day and don't visit locations that vary much.
>
> --
> -----
> change "netto" to "net" to email me directly
>
> Eric Greenwell
> Washington State
> USA
>

Since this is early January we can knock this one around a bit. The "sweet
spot" argument for 18 meters ignores all but weather and wingspan.

It seems to me that the Skylark 4 was 18 meters as were several 1960's
vintage wood and metal gliders so 18 meters could and was done then, albeit
with a bit more effort than 15. I have never been too comfortable with the
idea that cost and wingspan had a high correlation. Most designers I have
talked to say that adding wingspan is the cheapest way to add performance.

For a decision made in the early 1970's, 15 meters was arguably not a bad
choice. The error, if there was one, is not too have allowed for
improvement in aerodynamics and materials. (Not too sure how they would
have done that.) The "low cost" goal for the Standard Class doesn't seem to
have worked out too well though.

Bill Daniels

Marc Ramsey

January 9th 04, 01:04 AM

Eric Greenwell wrote:
> Here's my recollection of the genesis of the 15 meter class. Real
> historians please fill in the gaps and correct errors.

My recollection is a little different. I could be wrong, but I
distinctly remember discussion of a future 17M racing class, and that
the Kestrel 17 was the first glider designed to compete in it. The year
before the first FAI 17M competitions were to take place, there was
much gnashing of teeth and wailing amongst to be heard from the H301
owners that they would all have to replace their 3 or 4 year old gliders
with Kestrels to be competitive. There were a lot of prominent Libelle
owners, and very few Kestrel owners. The IGC meeting came and went,
there was a new 15M racing class, and everyone acted like there had
never been any discussion of a 17M class.

I think that was my first inkling of just how political this sport can
be. Some things never change...

Marc

Jim Phoenix

January 9th 04, 01:12 AM

> Interesting.
>
> I recall a technical discussion a long time ago asking whether there was a
> "natural best wingspan" imposed by the nature of soaring weather. The
> question was this: "Ignoring competition classes, is there a single best
> wingspan that is suited for the widest range of soaring conditions? The
> answers converged around 18 meters. Larger spans were considered too slow
> in strong conditions and smaller spans suffered in weak conditions. It's
> interesting that the "most cost effective wingspan" is about the same.
>
> This makes me wonder if eventually the 18 meter class will become dominant.
> It also makes me wonder if the selection of 15 meters for the two most
> popular classes was an error.
>
> Bill Daniels

If this was true, why do the 25m gliders win the Open class
competitions? Why aren't the LS8-18's and V2C's etc. cleaning up on
the ASH-25's?

Maybe I'm missing something... but maybe not - didn't a Ventus win
open in SA recently (I could be mistaken).

Jim

Bill Daniels

January 9th 04, 02:37 AM

"Jim Phoenix" > wrote in message
om...
> > Interesting.
> >
> > I recall a technical discussion a long time ago asking whether there
was a
> > "natural best wingspan" imposed by the nature of soaring weather. The
> > question was this: "Ignoring competition classes, is there a single
best
> > wingspan that is suited for the widest range of soaring conditions? The
> > answers converged around 18 meters. Larger spans were considered too
slow
> > in strong conditions and smaller spans suffered in weak conditions.
It's
> > interesting that the "most cost effective wingspan" is about the same.
> >
> > This makes me wonder if eventually the 18 meter class will become
dominant.
> > It also makes me wonder if the selection of 15 meters for the two most
> > popular classes was an error.
> >
> > Bill Daniels
>
> If this was true, why do the 25m gliders win the Open class
> competitions? Why aren't the LS8-18's and V2C's etc. cleaning up on
> the ASH-25's?
>
> Maybe I'm missing something... but maybe not - didn't a Ventus win
> open in SA recently (I could be mistaken).
>
> Jim

Hi, Jim.

I like big gliders too.

I don't think these guys were talking about existing gliders. They were
just asking, if you designed a glider for speed, what wingspan would you
choose, ignoring all else? The consensus was 18 meters.

With carbon rods, you could probably build a 60 meter glider but would it go
fast? Probably not. There is likely to be an upper limit imposed by
soarable meteorological conditions. There may also be a sweet spot
somewhere around 18 meters. If that turned out to be the case, and it was
also the most "cost effective span", the 18 meter class would be a "natural
class". I find that a pleasing thought.

Bill Daniels
Nimbus 2C

Fantsu

January 9th 04, 06:25 AM

"Ian Strachan" > wrote in message
...
> No, but some of the German manufacturers proposed 16 m, which was so
> close to the 15m flapped ships already being built (like the Pik 15)
> that IGC decided to stick with 15m.

Just a bit of nit-picking, but it was Pik-20. Pik-15 "Hinu" is a towing
plane...

regards,

h

Bob Kuykendall

January 9th 04, 04:43 PM

Earlier, "Bill Daniels" > wrote:

> With carbon rods, you could probably build a 60 meter glider...

Now, let's hang on for a second while I use that as an excuse to
hijack this thread. :)

As strong as those pultruded rods and strips are, they offer only a
20% or so increase in stiffness (per weight or per volume) over wet
layups of dry carbon tape. For gliders, and especially for long-winged
gliders, the structural design is bounded by stiffness, not strength.
As such, pultruded carbon rods buy you only a relatively modest
premium over more conventional arrangements of carbon materials.

It's the stiffness, in both bending and in torsion, that keeps gliders
from fluttering themselves to pieces. It's also the stiffness that
keeps exterior finishes like gelcoat happy.

The reason I so dearly love those pultruded rods and strips is that
they represent an extremely effectively packaged solution for the
low-tech glider builder like me. I don't need any expensive autoclaves
or fiber alignment equipment or resin calibration/saturation stuff. I
just grab a bunch of pultruded strip off the spool and go with it.

As for 60-meter gliders (that's just under 197 feet for us
metrically-challenged folks), I happen to believe that they're
possible, but not very probable. But I see the limitations as being
more operational than meterological. There are few places to launch or
land one of them, let alone a contest full of them.

Personally, I think that 15 meter ships are close enough to the sweet
spot for all practical purposes. They fit easily in trailers, hangars,
fields, and launch grids. The pieces are relatively light. And 18
meters is only a wingtip-change away.

Thanks, and best regards to all

Bob K.
http://www.hpaircraft.com

JJ Sinclair

January 9th 04, 04:53 PM

Jim wrote>>>>>>>>>..>
>Maybe I'm missing something... but maybe not - didn't a Ventus win
>open in SA recently (I could be mistaken).

I believe the Ventus won open the year we tried handicapping open class to
improve participation (US). We immediately dropped that idea because open was
in danger of losing again to another kiddy glider. I too believe that 18 meter
is about the best span for a single place ship. When 18 meter class came out, I
first thought that Standard class would slowly disappear, but they seem to be
as strong as any class. Will 15 meter slowly evolve into 18 meter? Just
thinking out loud, no need to tense up, all you 15 meter drivers. If it takes
as long to happen as 18 meter has, your 15 meter ships will all be 25 years old
and being flown by little old ladies from Placerville, anyway.
Cheers,
JJ Sinclair

Mark James Boyd

January 9th 04, 05:16 PM

>> I think the 18 meter class has been driven by motorglider considerations
>> much more than any natural "sweet spot" in performance/$. And frankly,
>> to even claim that 18 meters is the "sweet spot" is a subjective
>> judgment. Lot's of people prefer smaller gliders, and many prefer bigger
>
>Since this is early January we can knock this one around a bit. The "sweet
>spot" argument for 18 meters ignores all but weather and wingspan.
>

I don't think span is important. Instead it is aspect ratio. Any builder
can make span cheaply. A longer wingspan with larger mean
chord is useless and trivial. If all we wanted was span, this
would be VERY cheap.

Hmmm...it also strikes me that weight is very important to this discussion.
A 100# solo pilot is probably not getting the best performance for the
dollar from a DG-1000.

What I'd want is a minimum wing loading that, with me as the pilot,
supported a polar I like. What polar I like depends on the
conditions I fly in (floater or penetrator). I wouldn't want
to have to add ballast for every flight to get the polar I normally
like, since this would mean I paid for too much wing.

Having picked the wing loading, I'd now buy the highest aspect ratio
I could afford. As technology advances, this means I get more
and more span.

But technology for reducing weight seems to have outpaced
technology for increasing aspect ratio. So at the end of this
discussion, I'd like a Sparrowhawk for the dollar, instead of
something else. I'd prefer a much lighter glider with a
shorter wingspan and no ballast to a heavier one with more
span and the same aspect ratio.

I actually like LESS wing area with the same loading as my ideal
polar. Because the min sink part of the polar is 20 to 100 ft/min
less, the high speed part also gains this advantage. At the
super light weight, we can use a MUCH slicker airfoil and get the
same stall speed as a glider twice the weight. And we don't have
to beef up the fuse for heavy wings, then make the
wings larger for the weight, etc... (diminishing returns).

The tough decisions are: is retract worth the extra weight? And is
the glider sturdy enough to be flown in/out of typical strips
at my skill level (bumps and ruts included)? The Sparrowhawk
is an excellent concept theoretically, but is it sturdy?
As a very lightweight pilot, I'd be very interested in a
similarly light glider, but I sure wouldn't want to BREAK it.
Tiny main and tailwheels, and a fragile tailboom, can be a
real practical drawback...

It sure is fun to browse all the exciting equipment at each extreme...

Ian Strachan

January 9th 04, 05:24 PM

In article >, Fantsu
> writes
>
>"Ian Strachan" > wrote in message
...
>> No, but some of the German manufacturers proposed 16 m, which was so
>> close to the 15m flapped ships already being built (like the Pik 15)
>> that IGC decided to stick with 15m.
>
>Just a bit of nit-picking, but it was Pik-20. Pik-15 "Hinu" is a towing
>plane...

You are quite right, thanks for the correction. I meant the Pik 15
metre (or Pik 20).

On the motor glider front, I flew a Pik20E for some years in the UK.. I
always thought the span a bit short for our weak conditions when
carrying the extra weight of a self-launching engine. I wrote to Pik in
Finland suggesting an 18m version. They did in fact produce a 17m
version, the Pik 30E, but once DG produced the DG400 it was the DG that
sold rather than the Pik 30. I liked the Pik engineering, though, it
was nice and simple (as much as it can be with a self-launcher).

--
Ian Strachan
Lasham, UK

J. Eduardo P. Pontes

January 9th 04, 09:28 PM

Does someby know a set of specs for the Diana 2 similar to those =
supplied for the American Duck Eagle ?

Stewart Kissel

January 9th 04, 09:57 PM

Snip

>I don't think span is important. Instead it is aspect
>ratio. Any builder
>can make span cheaply.
Snip

Piloting skill makes up for a lot of span, aspect ratio
and weight.

Janusz Kesik

January 9th 04, 11:22 PM

Every salesman or designer will criticeze market competitors, so it's =
not strange for me that they beat the Diana as much as they can. :)

Regards,

--=20
Janusz Kesik

visit www.leszno.pl - home of the www.css-leszno.it.pl

> The design shows some clever features, but I heard German designers =
having
> some
> doubts if the glider really would pass all JAR requirements.

Jim Phoenix

January 10th 04, 12:37 AM

(JJ Sinclair) wrote in message >...
> JJ wrote>>>>>>>>>..>
>I too believe that 18 meter is about the best span for a single place ship.>

Yeah, certainly more convenient!

Jim

Kirk Stant

January 10th 04, 01:01 AM

(Mark James Boyd) wrote in message news:<3ffef018$1@darkstar>...
>
> Hmmm...it also strikes me that weight is very important to this discussion.
> A 100# solo pilot is probably not getting the best performance for the
> dollar from a DG-1000.

It's not the weight of the pilot, it's the weight of the plane that
counts. That's what ballast is for. Sure, you could build a 99/100th
scale DG-1000 just for the 100 lb pilot - but why? And it wouldn't be
cheap!
>
> What I'd want is a minimum wing loading that, with me as the pilot,
> supported a polar I like. What polar I like depends on the
> conditions I fly in (floater or penetrator). I wouldn't want
> to have to add ballast for every flight to get the polar I normally
> like, since this would mean I paid for too much wing.

The problem with this approach is that you are tailoring your glider
to one specific condition - and give away the wonderful game of
tailoring a glider's wingloading to the actual condition you are
flying in. A floater in the spring is nice, but is no fun in the
middle of summer when 10 knotters roam the desert and you need an IFR
clearance to climb to cloudbase! BTW, that is probably a big part of
the PW-5 problem - too much of a one-trick pony...IMHO.

>
> Having picked the wing loading, I'd now buy the highest aspect ratio
> I could afford. As technology advances, this means I get more
> and more span.
>
> But technology for reducing weight seems to have outpaced
> technology for increasing aspect ratio. So at the end of this
> discussion, I'd like a Sparrowhawk for the dollar, instead of
> something else. I'd prefer a much lighter glider with a
> shorter wingspan and no ballast to a heavier one with more
> span and the same aspect ratio.
>
> I actually like LESS wing area with the same loading as my ideal
> polar. Because the min sink part of the polar is 20 to 100 ft/min
> less, the high speed part also gains this advantage. At the
> super light weight, we can use a MUCH slicker airfoil and get the
> same stall speed as a glider twice the weight. And we don't have
> to beef up the fuse for heavy wings, then make the
> wings larger for the weight, etc... (diminishing returns).
>
> The tough decisions are: is retract worth the extra weight? And is
> the glider sturdy enough to be flown in/out of typical strips
> at my skill level (bumps and ruts included)? The Sparrowhawk
> is an excellent concept theoretically, but is it sturdy?
> As a very lightweight pilot, I'd be very interested in a
> similarly light glider, but I sure wouldn't want to BREAK it.
> Tiny main and tailwheels, and a fragile tailboom, can be a
> real practical drawback...

The whole Sparrowhawk thing scares me to death! When I'm bashing
around at 130 knots, I want my glider to have a certain structural
authority! Same thing when landing on some strange desert airstrip
for the first time. And don't get me started on the whole unregulated
ultralight glider thing!!! IMPORTANT SAFETY TIP FOR ANY NON-LICENCED
"PILOT" DROOLING OVER A SPARROWHAWK BROCHURE: Get the training, take
the damn test, get a licence, and fly a real glider, for goodness
sake! Or at least make me the beneficiary on you life insurance
policy...

As a very lightweight pilot, you have the advantage of an even greater
wingloading spread available to use, which can be a nice advantage
early in the season or late in the day - why give it away?

> It sure is fun to browse all the exciting equipment at each extreme...

You're damn right about that! And congratulations on your CFIG, BTW!

Kirk
A not very lightweight pilot

Eric Greenwell

January 10th 04, 02:37 AM

Kirk Stant wrote:

> The whole Sparrowhawk thing scares me to death! When I'm bashing
> around at 130 knots, I want my glider to have a certain structural
> authority!

Why do you think the SparrowHawk doesn't have "structural authority"?

> Same thing when landing on some strange desert airstrip
> for the first time.

Are you suggesting that the 15 meter LS-6 you fly would be easier to
land safely than the 11 meter SparrowHawk? Why would that be? Besides
being a lot smaller span (an asset when landing out, I think), the
SparrowHawk I flew landed slower than the 15 meter gliders I've flown.

> And don't get me started on the whole unregulated
> ultralight glider thing!!!
> IMPORTANT SAFETY TIP FOR ANY NON-LICENCED
> "PILOT" DROOLING OVER A SPARROWHAWK BROCHURE: Get the training, take
> the damn test, get a licence,

Excellent advice, and echos what SparrowHawk people recommend.

> and fly a real glider

I beg your pardon, but what isn't "real" about the SparrowHawk? From the
FAA registration database:

N-number : N40437
Aircraft Serial Number : 004
Aircraft Manufacturer : COLE GREGORY M
Model : SPARROW HAWK
Aircraft Year :
Owner Name : COLE GREGORY M
Owner Address : 2988 NE ROCKCHUCK DR
BEND, OR, 97701-6515
Type of Owner : Individual
Registration Date : 12-Jun-2003
Airworthiness Certificate Type : Not Specified

--
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Eric Greenwell
Washington State
USA

Bob Kuykendall

January 10th 04, 05:34 PM

Earlier, (Kirk Stant) wrote:

> ...The whole Sparrowhawk thing
> scares me to death! When I'm
> bashing around at 130 knots,
> I want my glider to have a
> certain structural authority!...

Kirk, have you ever actually handled one of those things?

Bob K.

Armando Pucci

January 10th 04, 10:50 PM

SZD-56-2, Diana 2: Newest 15-meter Sailplane

The technologically advanced SZD-56-2 Diana 2 will
soar on new wings next summer. Bogumil Beres, chief
design engineer of the Diana and owner of Biuro Projektowe
'B' Bogumil Beres, recently announced the design project
of a breakthrough Diana 2, featuring a curved wing
platform with a continuously varying airfoil and high-performance
winglets. The original Diana fuselage will be retained,
but with a lower drag fuselage-wing junction. The wing
loading range will be 6.08 - 11.7 psf. Most remarkably,
the Diana 2 will break the long-standing 15-meter glide
ratio barrier of 50/1 with room to spare: forecast
performance includes a max L/D of 52/1. Krzysztof Kubrynski
Ph.D of the Warsaw Institute of Technology has created
the Diana 2 airfoils using his custom 3-D computer
software. Mr. Kubrynski has worked extensively with
Delft University's Prof. Loek Boremans, who has designed
airfoils for many of the latest German competition
sailplanes. The prototype Diana 2 wings will fly next
August. Diana 2's will be delivered in the Spring of
2005.

Ventus 2cM (AR)

Mark James Boyd

January 11th 04, 03:01 AM

In article >,
Kirk Stant > wrote:
>
>The problem with this approach is that you are tailoring your glider
>to one specific condition - and give away the wonderful game of
>tailoring a glider's wingloading to the actual condition you are
>flying in. A floater in the spring is nice, but is no fun in the
>middle of summer when 10 knotters roam the desert and you need an IFR
>clearance to climb to cloudbase! BTW, that is probably a big part of
>the PW-5 problem - too much of a one-trick pony...IMHO.
>

I think a glider which is designed to be good in a wide variety of
conditions is great in none of them. Having said that, I think the
gliders which weigh less AND have a higher aspect ratio provide
more promise for the sport than the ETA's of the world. I was
pleased by the choices of the Diana and Sparrowhawk designers
to make a fast airfoil instead of focussing on low stall speed
and minimum sink. Neat, neat stuff...

>The whole Sparrowhawk thing scares me to death! When I'm bashing
>around at 130 knots, I want my glider to have a certain structural
>authority! Same thing when landing on some strange desert airstrip

Having never flown it, and having no experience with any glider structural
failure, I may have to wait until a few reports have come in.
Sort of like the difference between the DA-40 and the Cirrus, which
really only became starkly clear after they'd flown quite a bit,
some accident reports had come in, and the insurance carriers
made their conclusions. I am hopeful and optimistic, but only
the test of time will tell...

>
>> It sure is fun to browse all the exciting equipment at each extreme...
>
>You're damn right about that! And congratulations on your CFIG, BTW!

Thank you, Kirk. I'm glad to be a part of the sport.

>
>Kirk
>A not very lightweight pilot

Mark

Not a very heavyweight pilot

Kirk Stant

January 11th 04, 03:11 PM

(Bob Kuykendall) wrote in message >...

> Kirk, have you ever actually handled one of those things?

No, unfortunately I havn't, so my opinion is worth precisely what you
paid for it! I am obviously making an assumption, and I hope I'm
proven wrong, by the way, as the Sparrowhawk looks like a nice little
glider, but my real concern is triggered by the emphasis on the
"ultralight" aspect, which obviously drives the 155lb (!) weight of
the glider - I can't help but wonder where the weight has been saved.
By the VNE and G limits, it seems to have faily strong wings, so I'm
guessing the fuselage is a real eggshell...

And I truly hope that an "ultralight" Sparrowhawk (i.e. no N number)
never shows up in the hands of an untrained, unlicenced non-pilot,
because I think that is a sure way to kill or injure someone, real
quick!

Has anyone out there actually touched and/or flown a Sparrowhawk? How
about an eyewitness report - I havn't eaten any crow in a while...

Kirk

Kirk Stant

January 11th 04, 04:18 PM

Eric Greenwell > wrote in message >...

> I beg your pardon, but what isn't "real" about the SparrowHawk? From the
> FAA registration database:
>
> N-number : N40437
> Aircraft Serial Number : 004
> Aircraft Manufacturer : COLE GREGORY M
> Model : SPARROW HAWK
> Aircraft Year :
> Owner Name : COLE GREGORY M
> Owner Address : 2988 NE ROCKCHUCK DR
> BEND, OR, 97701-6515
> Type of Owner : Individual
> Registration Date : 12-Jun-2003
> Airworthiness Certificate Type : Not Specified

Eric,

Sorry, no disrespect intended, in your case the N number absolutely
makes it real. I have no problem with a registered glider flown by a
licenced pilot, which is obviously what you are - and from what I've
read it sounds like you are having a lot of fun. My fear if for the
unlicenced pilot flying an unregistered (or deregistered?)
Sparrowhawk. That is a dangerous situation, in my opinion. Push the
Sparrowhawk as a 1-26 replacement - or the saviour of fun soaring in
the US, fine, go for it!; sell it as an ultralight that "anybody" can
fly is scary! And sure, the manufacturer can insist on training, but
what happens when that Sparrowhawk is resold? Off comes the
N-number...

I guess I should shut up until I've been able to put my grubby little
paws on a real live Sparrowhawk. Or better yet a Duckhawk - can't
wait to fly against one of those and see if it is really a
breakthrough concept! Time - and a few competitions - will tell!

Kirk

soarski

January 11th 04, 05:06 PM

Armando Pucci > wrote in message >...
> SZD-56-2, Diana 2: Newest 15-meter Sailplane
>
> The technologically advanced SZD-56-2 Diana 2 will
> soar on new wings next summer. Bogumil Beres, chief
> design engineer of the Diana and owner of Biuro Projektowe
> 'B' Bogumil Beres, recently announced the design project
> of a breakthrough Diana 2, featuring a curved wing
> platform with a continuously varying airfoil and high-performance
> winglets. The original Diana fuselage will be retained,
> but with a lower drag fuselage-wing junction. The wing
> loading range will be 6.08 - 11.7 psf. Most remarkably,
> the Diana 2 will break the long-standing 15-meter glide
> ratio barrier of 50/1 with room to spare: forecast
> performance includes a max L/D of 52/1. Krzysztof Kubrynski
> Ph.D of the Warsaw Institute of Technology has created
> the Diana 2 airfoils using his custom 3-D computer
> software. Mr. Kubrynski has worked extensively with
> Delft University's Prof. Loek Boremans, who has designed
> airfoils for many of the latest German competition
> sailplanes. The prototype Diana 2 wings will fly next
> August. Diana 2's will be delivered in the Spring of
> 2005.
>
> Ventus 2cM (AR)

............AND It is called the Duckhawk????? Tranlated from Polish?

Eric Greenwell

January 11th 04, 05:40 PM

Kirk Stant wrote:

> Eric,
>
> Sorry, no disrespect intended, in your case the N number absolutely
> makes it real. I have no problem with a registered glider flown by a
> licenced pilot, which is obviously what you are - and from what I've
> read it sounds like you are having a lot of fun.

I don't own one, but I have flown one a couple of times, and have talked
with a couple of the owners quite bit.

> My fear if for the
> unlicenced pilot flying an unregistered (or deregistered?)
> Sparrowhawk. That is a dangerous situation, in my opinion.

Not if the pilot is competent, of course, but I think I know what you
mean: potentially, the pilot might be untrained and outside the usual
network of oversight, such as biennials. Windward Performance knows
this, and if you look at their website, you will see that they don't
push this aspect of the glider. Windward Performance wants this to be a
successful glider, and crashes are bad news.

> Push the
> Sparrowhawk as a 1-26 replacement - or the saviour of fun soaring in
> the US, fine, go for it!; sell it as an ultralight that "anybody" can
> fly is scary!

As I said, they don't do this. Remember that Greg Cole, the designer,
makes his living designing real aircraft (e.g., he was the principal
engineer on Lancair's certified Columbia 300 and currently consults for
Adam Aircraft). It's my understanding every current customer will be a
licensed glider pilot by the time they take delivery (most of them were
before they ordered one, anyway).

Practically speaking, it's expensive enough that it's very unlikely that
an inexperienced person is going to by one, anyway.

And sure, the manufacturer can insist on training, but
> what happens when that Sparrowhawk is resold? Off comes the
> N-number...

If someone wants to fly, say, a 1-26 without a license or training,
there is little to stop them. Buy one, take it to dry lake, and car tow
it. Determined ignorance, stupidity, or arrogance can easily work
outside the system.

> I guess I should shut up until I've been able to put my grubby little
> paws on a real live Sparrowhawk. Or better yet a Duckhawk - can't
> wait to fly against one of those and see if it is really a
> breakthrough concept! Time - and a few competitions - will tell!

I'm waiting until they have a chance to put that motor in the SparrowHawk...

--
-----
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Eric Greenwell
Washington State
USA

Eric Greenwell

January 11th 04, 07:30 PM

Kirk Stant wrote:
> (Bob Kuykendall) wrote in message
> >...
>
>
>> Kirk, have you ever actually handled one of those things?
>
>
> No, unfortunately I havn't, so my opinion is worth precisely what you
> paid for it! I am obviously making an assumption, and I hope I'm
> proven wrong, by the way, as the Sparrowhawk looks like a nice little
> glider, but my real concern is triggered by the emphasis on the
> "ultralight" aspect, which obviously drives the 155lb (!) weight of
> the glider - I can't help but wonder where the weight has been saved.
> By the VNE and G limits, it seems to have faily strong wings, so I'm
> guessing the fuselage is a real eggshell...

It's light but strong, and the wing spars are fabricated before
installation. The weight isn't saved so much as _avoided_ by using an 11
meter span, a lower Vne (123 knots) than higher wing loading gliders,
fixed gear, no flaps, and pre-preg carbon fiber construction instead of
wet lay-up. There is some weight savings from using a few custom items
like the towhook.

>
> And I truly hope that an "ultralight" Sparrowhawk (i.e. no N number)
> never shows up in the hands of an untrained, unlicenced non-pilot,
> because I think that is a sure way to kill or injure someone, real
> quick!
>
> Has anyone out there actually touched and/or flown a Sparrowhawk?
> How about an eyewitness report - I havn't eaten any crow in a
> while...

I wrote two articles for Soaring, one on the design and construction
(Jan 2001 - also available on their website), and one on flying it (July
2002). Number 10 is due to be delivered this month, so there are a
number flying, and you are probably aware of Gary Osoba's World records
set with the glider.

--
-----
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Eric Greenwell
Washington State
USA

Mark James Boyd

January 11th 04, 09:39 PM

In article >,
Mike Borgelt > wrote:
>On Sun, 11 Jan 2004 09:40:25 -0800, Eric Greenwell
> wrote:
>
>
>>
>>I'm waiting until they have a chance to put that motor in the SparrowHawk...
>
>Take a look at the movie clip of the Silent IN with the Jet engines. I
>ran some numbers on the engines over the weekend and I'm convinced
>I've seen the future of soaring.
>
>Mike Borgelt

I've come to much the same conclusion as Mike. I'd use a single
more powerful turbine (maybe the 1500) instead of 2, but
the numbers seem to work for even fairly short fields.

The heat on the tail scares me though. Hmmm...how do we
get rid of the glider tail? ;)

Mike Borgelt

January 11th 04, 09:46 PM

On Sun, 11 Jan 2004 09:40:25 -0800, Eric Greenwell
> wrote:

>
>I'm waiting until they have a chance to put that motor in the SparrowHawk...

Take a look at the movie clip of the Silent IN with the Jet engines. I
ran some numbers on the engines over the weekend and I'm convinced
I've seen the future of soaring.

Mike Borgelt

Andreas Maurer

January 12th 04, 12:14 AM

On Mon, 12 Jan 2004 07:46:52 +1000, Mike Borgelt
> wrote:

>Take a look at the movie clip of the Silent IN with the Jet engines. I
>ran some numbers on the engines over the weekend and I'm convinced
>I've seen the future of soaring.

:)
Search for a glider called "Huetter 30 TS"... (look here, for example:
http://vintagesailplanes.de/Huetter30TS.htm). First flight was in
1960.

It later became the Libelle and Salto... but it failed miserably with
the turbine engine although it was a very good glider. Noise, fuel
consumption and bad climb rates were the killer factors.

Bye
Andreas

Andreas Maurer

January 12th 04, 12:16 AM

On 11 Jan 2004 14:39:20 -0700, (Mark James Boyd)
wrote:

>The heat on the tail scares me though. Hmmm...how do we
>get rid of the glider tail? ;)

Why would you want that?
Many have tried it, an noone came even close to a conventional layout
(the compromise design Genesis was the only one that offered similar
handling wualities and performances as a conventional glider).

Having no tail is less of an advantage if your wing has twice the
drag...
Bye
Andreas

Doug Taylor

January 12th 04, 12:58 AM

Kirk,

Where do you fly from? I am trying to make some plans for travelling
with my SparrowHawk over the next few months. I am hoping to show the
SparrowHawk to as many people as want to see it, and hopefully convert
a few "non-believers". I would be very happy to have the opportunity
to show it to you and other people that would be interested in seeing
it. For a few qualified individuals there might even be the
opportunity to fly it.

Until you see it and feel it, I can understand how hard it is for
people to grasp just what kind of accomplishment this glider is. 155
pounds!? Ridiculous! That is if you are not familiar with the
materials. The carbon pre-preg and the adhesives used to bond the
plane together are totally different and more than twice as strong as
what is typically used to build sailplanes. We joke about how we
could take our rudder and use it to chop up every other glider on the
field. This really isn't far from truth. One used as a display
sample by the manufacturer of the pre-preg has been through the
airlines baggage handling system without the benefit of a box. If
anything can survive that....!

Is it possible to break it? Of course. One SparrowHawk did suffer
some damage to its landing gear while landing out last summer, however
the pilot reported that it is one heck of a strong airplane and the
tailboom would likely have broken on any of his other sailplanes.
Mine has been landed out a couple of times and it has flown off of
some fairly rough strips as well as suffering some of my landings.
All it has to show for this are some paint scratches. No dents or
cracks. Structural testing has been done to the wings, vertical tail,
horzontal tail, seat, fuselage and tow hook, as well as the control
system.

As far as performance goes, like one SparrowHawk owner said, on an
average day, flown by average pilots in an average way, it doesn't
really give up anything. Some trade-offs were made to make it a very
easy glider to fly for less experienced pilots (every CFIG who has
flown it has said it would be a good first single seater). Stalls
including fully cross controlled with the stick held full aft through
a number of cycles are a non-event. Control response and harmony is
excellent down to very low speeds making take-off and landing very
easy. So what is the trade-off? Up to about 60 knots, there isn't
really any. Above that, most of the newer 15M gliders do have a
performance advantage. That doesn't mean that the SparrowHawk falls
out of the sky though. At 80 knots it is still getting around 20:1
L:D. It has flown a 300 km triangle with a 25 knot wind blowing and
averaged 52 mph.

I realise that this is all talk until you actually see it, that is why
I would like to have the opportunity to show the plane to as many
people as possible over the next few months. Anyone who would like to
see it, please let me know.

Best regards,

Doug Taylor

ps. I am not an employee of Windward Performance, although I did help
out on the construction of tooling and the first few SparrowHawks. I
am just trying to help spread the word because I believe this is one
fantastic machine!

(Kirk Stant) wrote in message

> No, unfortunately I havn't, so my opinion is worth precisely what you
> paid for it! I am obviously making an assumption, and I hope I'm
> proven wrong, by the way, as the Sparrowhawk looks like a nice little
> glider, but my real concern is triggered by the emphasis on the
> "ultralight" aspect, which obviously drives the 155lb (!) weight of
> the glider - I can't help but wonder where the weight has been saved.
> By the VNE and G limits, it seems to have faily strong wings, so I'm
> guessing the fuselage is a real eggshell...
>
> And I truly hope that an "ultralight" Sparrowhawk (i.e. no N number)
> never shows up in the hands of an untrained, unlicenced non-pilot,
> because I think that is a sure way to kill or injure someone, real
> quick!
>
> Has anyone out there actually touched and/or flown a Sparrowhawk? How
> about an eyewitness report - I havn't eaten any crow in a while...
>
> Kirk

Mike Borgelt

January 12th 04, 04:24 AM

On 11 Jan 2004 14:39:20 -0700, (Mark James Boyd)
wrote:

>In article >,
>Mike Borgelt > wrote:
>>On Sun, 11 Jan 2004 09:40:25 -0800, Eric Greenwell
> wrote:
>>
>>
>>>
>>>I'm waiting until they have a chance to put that motor in the SparrowHawk...
>>
>>Take a look at the movie clip of the Silent IN with the Jet engines. I
>>ran some numbers on the engines over the weekend and I'm convinced
>>I've seen the future of soaring.
>>
>>Mike Borgelt
>
>I've come to much the same conclusion as Mike. I'd use a single
>more powerful turbine (maybe the 1500) instead of 2, but
>the numbers seem to work for even fairly short fields.
>
>The heat on the tail scares me though. Hmmm...how do we
>get rid of the glider tail? ;)

The guys with the Silent don't seem to have a problem with the heat on
the tail - the two AMT 450 turbines seem to be mounted parallel to the
centerline. If this still worries you a V tail as on HP gliders or the
Salto is the easy answer.

I first thought of using the AMT1500 but when you do the numbers two
AMT450s (and soon the XP versions with about 10% more thrust) are
quite adequate for a 400kg glider. 50 feet at 500m takeoff run under
standard day sea level conditions seems doable, over 500 fpm rate of
climb at about 90 knots, single engine out climb of close to 200fpm at
70 knots. It makes a pretty good sustainer. (A real "turbo"!) Fuel
consumption on one engine is about 0.5kg/min , two is 1kg/min. Given
that a 2000 foot launch will only take about 4 minutes it is about as
fuel efficient as a launch behind a Pawnee.

Imagine self launcher with engine out capability and a decent climb
speed where you have significant energy for manouever even if both
engines fail!

Don't worry about ducting - extend the engine(s) on a short pylon.
They weigh so little and don't vibrate that this will be a very
lightweight structure, easy to extend and retract, solves any local
structural heat problems and the hole in the glider is so small, that
there will be minimal structural reinforcement required. The AMT 450
is 5.1" diameter and 10.7" long and weighs about 2.4kg (5 pounds or
so).

Great for motorising motorless gliders as the weight in the fuselage
is minimal. Convert part of the water tanks/bags for jet
fuel.60Kg(75liters) will give you one hour.

Now look at a Sparrowhawk

70kg empty

add say 10 kg for 1 x AMT450XP pylon and structural reinforcing

30 kg for 1 hours fuel.

add typical say 100 kg for pilot and chute etc

Only 210Kg!

One AMT 450 will self launch this adequately.
Two smaller engines may still be optimum for slightly increased thrust
and engine out capability.

Hope the Windward Performance guys have a plan to increase production
because if this works they might be swamped by customers.

These small turbines are still being developed - they will get better.
Engine pressure ratios are still only 4:1 or so, fuel consumption can
be improved.

Mike Borgelt

Mark James Boyd

January 12th 04, 05:15 AM

In article >,
Mike Borgelt > wrote:
>On 11 Jan 2004 14:39:20 -0700, (Mark James Boyd)
>wrote:
>
>>In article >,
>>Mike Borgelt > wrote:
>>
>>I've come to much the same conclusion as Mike. I'd use a single
>>more powerful turbine (maybe the 1500) instead of 2, but
>>the numbers seem to work for even fairly short fields.
>>
>>The heat on the tail scares me though. Hmmm...how do we
>>get rid of the glider tail? ;)
>
>
>The guys with the Silent don't seem to have a problem with the heat on
>the tail - the two AMT 450 turbines seem to be mounted parallel to the
>centerline. If this still worries you a V tail as on HP gliders or the
>Salto is the easy answer.

I've never seen a turbine airplane design that allows the hot exhaust
to reach a control surface of the aircraft. The fact that the Silent
flew a few times in this configuration is not convincing to me.
If the owner would put it on a stand in a hangar and
run it for an hour with his face right in front of the rudder/stab,
I'd change my tune. I don't have any hard facts or figures,
but my intuition sets off some warning flags here...

>I first thought of using the AMT1500 but when you do the numbers two
>AMT450s (and soon the XP versions with about 10% more thrust) are
>quite adequate for a 400kg glider.

The larger engine isn't for more thrust than two engines, but
just for the lower complexity of using one engine. Two engines are
best used in aircraft with high wing loading that carry
passengers through turbulence. Two engines in a light-wing
loaded aircraft is just unneccesary, IMHO. Engine failure is
a non-issue due to the glide ratio, and the reliability of turbines.
The added weight, wiring, two starters, fuel lines, etc. seem
silly if a single turbine can be used instead.

>Great for motorising motorless gliders as the weight in the fuselage
>is minimal. Convert part of the water tanks/bags for jet
>fuel.60Kg(75liters) will give you one hour.

Figuring out how to manage fuel from two tanks is a minor
complexity, and being able to dump fuel should ensure
one doesn't fly "chinese style" (won weeng lo).
It does seem using the fuel as ballast is an excellent feature,
but I'd want to really think hard about fire dangers.
Perhaps use less flammable fuel? I guess there is quite a
variety of fuel choices available...

>Now look at a Sparrowhawk
>One AMT 450 will self launch this adequately.
>Two smaller engines may still be optimum for slightly increased thrust
>and engine out capability.

More power than adequate = better. One can always throttle
back for fuel savings. I suspect the designers used two
engines instead of one because the 1500 may not be readily tested/
available rather than due to the need for redundancy. Again,
I've flown some twins and they have their uses; a powered glider
isn't a good match for two turbine powerplants
(just overkill/expense)...

>Hope the Windward Performance guys have a plan to increase production
>because if this works they might be swamped by customers.

The Sparrowhawk may be ideal for this application, but other
light gliders also have comparable potential. And I personally
would want to see a competitor which could taxi well.
A self-launch glider which has trouble taxiing is less
interesting to me personally than something more flexible.
Besides, the noise may get one banned from the gliderport and forced
to use a <gasp> towered airport... ;P

Mike Borgelt

January 12th 04, 09:44 AM

On 11 Jan 2004 22:15:26 -0700, (Mark James Boyd)
wrote:

>In article >,
>Mike Borgelt > wrote:
>>On 11 Jan 2004 14:39:20 -0700, (Mark James Boyd)
>>wrote:
>>
>>>In article >,
>>>Mike Borgelt > wrote:
>>>
>>>I've come to much the same conclusion as Mike. I'd use a single
>>>more powerful turbine (maybe the 1500) instead of 2, but
>>>the numbers seem to work for even fairly short fields.
>>>
>>>The heat on the tail scares me though. Hmmm...how do we
>>>get rid of the glider tail? ;)
>>
>>
>>The guys with the Silent don't seem to have a problem with the heat on
>>the tail - the two AMT 450 turbines seem to be mounted parallel to the
>>centerline. If this still worries you a V tail as on HP gliders or the
>>Salto is the easy answer.
>
>I've never seen a turbine airplane design that allows the hot exhaust
>to reach a control surface of the aircraft. The fact that the Silent
>flew a few times in this configuration is not convincing to me.
>If the owner would put it on a stand in a hangar and
>run it for an hour with his face right in front of the rudder/stab,
>I'd change my tune. I don't have any hard facts or figures,
>but my intuition sets off some warning flags here...
>

A few of us were brainstorming this this afternoon and we think that
mounting the turbines in the inside of the swing out doors solves this
completely. One engine ends up over each wing root. These things are
installed in R/C models so the heat issues are obviously manageable.
You can easily then cant then out a little if you want. Problem
solved(and a good argument for two engines)

>>I first thought of using the AMT1500 but when you do the numbers two
>>AMT450s (and soon the XP versions with about 10% more thrust) are
>>quite adequate for a 400kg glider.
>
>The larger engine isn't for more thrust than two engines, but
>just for the lower complexity of using one engine. Two engines are
>best used in aircraft with high wing loading that carry
>passengers through turbulence. Two engines in a light-wing
>loaded aircraft is just unneccesary, IMHO. Engine failure is
>a non-issue due to the glide ratio, and the reliability of turbines.
>The added weight, wiring, two starters, fuel lines, etc. seem
>silly if a single turbine can be used instead.

Given you will have only an electric fuel pump you are going to want
two anyway even for one engine. You already have two fuel tanks. You
might want two batteries as well to be sure of getting a start when
about to land out. Each of two smaller engines is lighter and simpler
to swing out than one larger one.
This looks one one of those issues where the "obvious" solution isn't
so obvious on reflection. The cost of the engines seems to scale
roughly with thrust so it is dollars per Newton you pay for.
The smaller engines also have thousands of hours operating history
which is worth a lot. And I *love* the idea of engine out capability
plus with two you really aren't going to fail to get at least one
running to avoid an outlanding.
>
>>Great for motorising motorless gliders as the weight in the fuselage
>>is minimal. Convert part of the water tanks/bags for jet
>>fuel.60Kg(75liters) will give you one hour.
>
>Figuring out how to manage fuel from two tanks is a minor
>complexity, and being able to dump fuel should ensure
>one doesn't fly "chinese style" (won weeng lo).
>It does seem using the fuel as ballast is an excellent feature,
>but I'd want to really think hard about fire dangers.
>Perhaps use less flammable fuel? I guess there is quite a
>variety of fuel choices available...

I figured on one tank in each wing anyway and jet fuel is much less
flammable than gasoline anyway.
>
>>Now look at a Sparrowhawk
>>One AMT 450 will self launch this adequately.
>>Two smaller engines may still be optimum for slightly increased thrust
>>and engine out capability.
>
>More power than adequate = better. One can always throttle
>back for fuel savings.

Climb to 1000 feet or so and shut one down, then go find a thermal.

> I suspect the designers used two
>engines instead of one because the 1500 may not be readily tested/
>available rather than due to the need for redundancy.

Yes and the redundancy is really nice to have. If the glider was not
capable of climbing on one I'd agree with you that one engine is
desirable but what is the point of designing around an engine that
isn't readily available with lots of operating history? The packaging
of two is also easier.

>I've flown some twins and they have their uses; a powered glider
>isn't a good match for two turbine powerplants
>(just overkill/expense)...

Think about it some more and look at the prices. I didn't think jet
gliders were at all viable until I ran the numbers.
>
>>Hope the Windward Performance guys have a plan to increase production
>>because if this works they might be swamped by customers.
>
>The Sparrowhawk may be ideal for this application, but other
>light gliders also have comparable potential. And I personally
>would want to see a competitor which could taxi well.
>A self-launch glider which has trouble taxiing is less
>interesting to me personally than something more flexible.
>Besides, the noise may get one banned from the gliderport and forced
>to use a <gasp> towered airport... ;P

I've seen and heard the R/C model jets fly. They aren't that noisy at
all. Two smaller engines over the wingroots actually shields the
people on the ground from much of the noise.

Taxiing is still going to be problematical but then very few existing
self launchers taxi well(as opposed to Stemme's, Katanas etc and even
they would have trouble at our airport.

I've got some time in the Jet Caproni about 20 years ago and I wasn't
that impressed. When I last flew in it 10 years ago the owner had
figured it out and it was good. We are talking the same sort of thrust
weight for a 400Kg glider(most 15/18m gliders) with two AMT 450's.

As for complexity of two jet engines compare with a horrible, heavy,
noisy vibrating two stroke with reduction drive and propeller, complex
and heavy extend /retract mechanism, heat issues if the engine is
buried in the fuselage and complex operating procedures with very
limited climb speed range. Look at the prices being charged for these
contraptions.

Mike Borgelt

Kirk Stant

January 12th 04, 02:36 PM

(Doug Taylor) wrote in message >...
> Kirk,
>
> Where do you fly from? I am trying to make some plans for travelling
> with my SparrowHawk over the next few months. I am hoping to show the
> SparrowHawk to as many people as want to see it, and hopefully convert
> a few "non-believers". I would be very happy to have the opportunity
> to show it to you and other people that would be interested in seeing
> it. For a few qualified individuals there might even be the
> opportunity to fly it.

Doug, thanks for the excellent response. I fly out of Turf Soaring,
near Phoenix Arizona - and would love the opportunity to see the
Sparrowhawk in action. I'll admit I'm a bit of a sceptic, but from
the reasoned responses from several of you out there it sounds like it
is a nice little glider.

I just wish the whole "ultralight" aspect would go away - that still
scares me. It may be a pretty moot point - I doubt anyone could show
up in an unregistered glider and get a tow at any glider operation I
know of!

One question: how do you buy a factory-built Sparrowhawk and register
it if it isn't certified yet? Or did I miss something. Just curious.

So come on out to Turf and show your stuff - on any weekend there will
be plenty of glass to keep you company on some XC or racing, and a
nice airconditioned clubhouse with cold beer and chicks waiting after
the flight (see Pez, he got it just about right, if you stay you will
have to race!).

Kirk

Mark James Boyd

January 12th 04, 04:41 PM

Mike Borgelt > wrote:

>As for complexity of two jet engines compare with a horrible, heavy,
>noisy vibrating two stroke with reduction drive and propeller, complex
>and heavy extend /retract mechanism, heat issues if the engine is
>buried in the fuselage and complex operating procedures with very
>limited climb speed range. Look at the prices being charged for these
>contraptions.

Compared to a two-stroke, four jet engines is an improvement.
But again, IMHO, one jet engine of the same power is better than
more engines in light wing-loaded aircraft. The complexity of
pilot management, and the extra workload to manage the feeding and
maintenance is the downside. And redundancy is, I believe,
notional. I'd rather run out of gas and then switch to a full
tank than run out of gas on one engine and then, a few seconds
later, run out of gas on the other side.

I hope we can agree as gentlemen to disagree on this one...
I'm strongly in favor of a single turbine engine for this
application.

>>I've never seen a turbine airplane design that allows the hot exhaust
>>to reach a control surface of the aircraft. The fact that the Silent
>>flew a few times in this configuration is not convincing to me.
>>If the owner would put it on a stand in a hangar and
>>run it for an hour with his face right in front of the rudder/stab,
>>I'd change my tune. I don't have any hard facts or figures,
>>but my intuition sets off some warning flags here...
>
>You can easily then cant then out a little if you want. Problem
>solved(and a good argument for two engines)

I just don't know how large the heat cones are out of these engines, so
I can't really agree or disagree...I don't think I can solve this
one from an armchair...

>Given you will have only an electric fuel pump you are going to want
>two anyway even for one engine. You already have two fuel tanks. You
>might want two batteries as well to be sure of getting a start when
>about to land out. Each of two smaller engines is lighter and simpler
>to swing out than one larger one.
>This looks one one of those issues where the "obvious" solution isn't
>so obvious on reflection. The cost of the engines seems to scale
>roughly with thrust so it is dollars per Newton you pay for.
>The smaller engines also have thousands of hours operating history
>which is worth a lot. And I *love* the idea of engine out capability
>plus with two you really aren't going to fail to get at least one
>running to avoid an outlanding.

Out of gas is out of gas, period. Turbines get more reliable as they
get larger, and are lots more reliable than anything with a prop.
The reliability card simply has negligible meaning in this context.
And again, the cost isn't the acquisition or fuel costs, it's
continuing cost...

>I figured on one tank in each wing anyway and jet fuel is much less
>flammable than gasoline anyway.

The fuel is slightly less flammable but the heat danger is much
greater than a pure glider (of course). My point is just that
if one has a choice, maybe use the least flammable fuel? You
can still fill up with Jet A if needed...
And I'm also emphasizing that I think the fire risk is really
something to pay attention to and minimize by design...

>Yes and the redundancy is really nice to have. If the glider was not
>capable of climbing on one I'd agree with you that one engine is
>desirable but what is the point of designing around an engine that
>isn't readily available with lots of operating history?
Completely true. If we MUST use two because of
marketing/availability/testing reasons
then fine. Two in the hand is better than none in the bush. But
accepting a sub-optimal design instead of making some extra phone
calls means somebody else is gonna compete with you later, at
a better price offering reduced maintenance/complexity...

>The packaging
>of two is also easier.
Boy I gotta strongly disagree with that.
Installing, testing, wiring, instrumenting, fueling,
operating, shutting down, diagnosing in flight, etc.
for two engines is wholly different than one.
There's a reason 727s have three crewmembers instead of one,
and it isn't because of the complexity of the passengers
or so the Captain can take a nap...

>I've seen and heard the R/C model jets fly. They aren't that noisy at
>all. Two smaller engines over the wingroots actually shields the
>people on the ground from much of the noise.

My comment about noise meaning you may get banned from the gliderport
was tongue in cheek. Here's the ;) that should have been there...

>Taxiing is still going to be problematical but then very few existing
>self launchers taxi well(as opposed to Stemme's, Katanas etc and even
>they would have trouble at our airport.
>
>I've got some time in the Jet Caproni about 20 years ago and I wasn't
>that impressed. When I last flew in it 10 years ago the owner had
>figured it out and it was good. We are talking the same sort of thrust
>weight for a 400Kg glider(most 15/18m gliders) with two AMT 450's.

>Mike Borgelt

Yes, I'd very much like to see taxi capability. A short wingspan and
light weight like a Sparrowhawk is excellent for this turbine.
The extra stuff to make it taxi well would sell it to the
biggest market, "power pilots," with the best success.

Mark Boyd

Eric Greenwell

January 12th 04, 04:58 PM

Mike Borgelt wrote:

>
> As for complexity of two jet engines compare with a horrible, heavy,
> noisy vibrating two stroke with reduction drive and propeller, complex
> and heavy extend /retract mechanism, heat issues if the engine is
> buried in the fuselage and complex operating procedures with very
> limited climb speed range. Look at the prices being charged for these
> contraptions.

Typical self-launchers are rpm limited to about 70-75 knot cruise, which
is painfully slow when flying into a 30-40 knot headwind while trying to
reach a wave. As a result, I often don't attempt to fly our best winter
waves, since it'd an hour+ to reach them. Being able to cruise at 100+
knots would cut the transit time in half.

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Washington State
USA

Eric Greenwell

January 12th 04, 05:11 PM

Kirk Stant wrote:
>
> I just wish the whole "ultralight" aspect would go away - that still
> scares me. It may be a pretty moot point - I doubt anyone could show
> up in an unregistered glider and get a tow at any glider operation I
> know of!

Don't they tow ultralights at Turf? You know, on the "other" side of the
airport? It doesn't take a 230 hp Pawnee to tow a 400 pound glider,
though it tows behind one just fine.

>
> One question: how do you buy a factory-built Sparrowhawk and register
> it if it isn't certified yet? Or did I miss something. Just curious.

It was registered in the Experimetal class, just like your LS-6.

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Washington State
USA

Bob Kuykendall

January 12th 04, 06:10 PM

Earlier, (Kirk Stant) wrote:

> One question: how do you buy a factory-
> built Sparrowhawk and register it if it
> isn't certified yet?

As Experimental, Racing or Experimental, Exhibition, just like an ASW-20.

Bob K.

Doug Taylor

January 12th 04, 07:16 PM

If you don't mind the drive to Estrella, my dad is there with his
SparrowHawk right now. Don't know how much longer he will be there
though. His is the bright orange one.

The ultralight thing is an issue for a lot of people. I don't think
anyone has ever proposed that you and yer buddies could haul it around
on a deserted road and figure out how to fly the thing. (hey y'all,
watch this!) The company has always said that the SparrowHawk should
only be flown with adequate training.

As far as getting a tow, the only thing that is usually asked for is
some kind of proof that the pilot is qualified. Without a license and
aerotow sign off, I would expect the pilot would be required to take a
tow with an instructor. Then it would be basically the same as a
student pilot on a solo flight.

Registration is exactly the same as most of the foreign glass that is
flying right now. All ASW-20's for example are factory built planes
that are not certified in the U.S.A. They are registered as
Experimental - Racing for the most part. Same as the SparrowHawks
that are registered.

I definitely am looking forward to getting to Turf. Once I get a
better idea of my plans, I will post a schedule and contact everyone
who has contacted me directly.

Happy flying,
Doug Taylor

> Doug, thanks for the excellent response. I fly out of Turf Soaring,
> near Phoenix Arizona - and would love the opportunity to see the
> Sparrowhawk in action. I'll admit I'm a bit of a sceptic, but from
> the reasoned responses from several of you out there it sounds like it
> is a nice little glider.
>
> I just wish the whole "ultralight" aspect would go away - that still
> scares me. It may be a pretty moot point - I doubt anyone could show
> up in an unregistered glider and get a tow at any glider operation I
> know of!
>
> One question: how do you buy a factory-built Sparrowhawk and register
> it if it isn't certified yet? Or did I miss something. Just curious.
>
> So come on out to Turf and show your stuff - on any weekend there will
> be plenty of glass to keep you company on some XC or racing, and a
> nice airconditioned clubhouse with cold beer and chicks waiting after
> the flight (see Pez, he got it just about right, if you stay you will
> have to race!).
>
> Kirk

Mike Borgelt

January 12th 04, 09:47 PM

On 12 Jan 2004 09:41:18 -0700, (Mark James Boyd)
wrote:

>Mike Borgelt > wrote:
>
>>As for complexity of two jet engines compare with a horrible, heavy,
>>noisy vibrating two stroke with reduction drive and propeller, complex
>>and heavy extend /retract mechanism, heat issues if the engine is
>>buried in the fuselage and complex operating procedures with very
>>limited climb speed range. Look at the prices being charged for these
>>contraptions.
>
>Compared to a two-stroke, four jet engines is an improvement.
>But again, IMHO, one jet engine of the same power is better than
>more engines in light wing-loaded aircraft. The complexity of
>pilot management, and the extra workload to manage the feeding and
>maintenance is the downside.

Even the jet Caproni was fly by wire for engine management. These
engines already come with automatic electronic controls. Not a heck of
a lot of complexity.

> And redundancy is, I believe,
>notional. I'd rather run out of gas and then switch to a full
>tank than run out of gas on one engine and then, a few seconds
>later, run out of gas on the other side.
>

I'm not worried about running out of gas, just Murphy's Law.

>I hope we can agree as gentlemen to disagree on this one...
>I'm strongly in favor of a single turbine engine for this
>application.

They simply are not available yet. Two smaller turbines are and have
some advantages and I beleive aren't likely to cost significantly more
than one large one.
>
>>>I've never seen a turbine airplane design that allows the hot exhaust
>>>to reach a control surface of the aircraft. The fact that the Silent
>>>flew a few times in this configuration is not convincing to me.
>>>If the owner would put it on a stand in a hangar and
>>>run it for an hour with his face right in front of the rudder/stab,
>>>I'd change my tune. I don't have any hard facts or figures,
>>>but my intuition sets off some warning flags here...
>>
>>You can easily then cant then out a little if you want. Problem
>>solved(and a good argument for two engines)
>
>I just don't know how large the heat cones are out of these engines, so
>I can't really agree or disagree...I don't think I can solve this
>one from an armchair...
>
>>Given you will have only an electric fuel pump you are going to want
>>two anyway even for one engine. You already have two fuel tanks. You
>>might want two batteries as well to be sure of getting a start when
>>about to land out. Each of two smaller engines is lighter and simpler
>>to swing out than one larger one.
>>This looks one one of those issues where the "obvious" solution isn't
>>so obvious on reflection. The cost of the engines seems to scale
>>roughly with thrust so it is dollars per Newton you pay for.
>>The smaller engines also have thousands of hours operating history
>>which is worth a lot. And I *love* the idea of engine out capability
>>plus with two you really aren't going to fail to get at least one
>>running to avoid an outlanding.
>
>Out of gas is out of gas, period. Turbines get more reliable as they
>get larger,

Maybe when you are talking about GE90 vs JT8D although I wouldn't bet
on it without doing some research. Down in the sizes we are talking
about do we have any real numbers?

> and are lots more reliable than anything with a prop.
>The reliability card simply has negligible meaning in this context.
>And again, the cost isn't the acquisition or fuel costs, it's
>continuing cost...

We aren't talking certified airplane engines here for either the
AMT450 or the AMT1500/1700. Redundancy may indeed be very nice to
have.
>
>>I figured on one tank in each wing anyway and jet fuel is much less
>>flammable than gasoline anyway.
>
>The fuel is slightly less flammable but the heat danger is much
>greater than a pure glider (of course). My point is just that
>if one has a choice, maybe use the least flammable fuel? You
>can still fill up with Jet A if needed...
>And I'm also emphasizing that I think the fire risk is really
>something to pay attention to and minimize by design...

I'm not sure thay make the fuel used in the SR71 anymore and it likely
wouldn't run in these engines.
The fuel and heat issues have been solved in the Jet Caproni with a
buried engine 25 years ago. There is a group in Australia converting
some non jet Caproni airframes to jet power. Same idea as Caproni but
allegedly a better and more refined installation and better
performance. I've seen it fly.

The little engines are used in R/C models. Obviously the heat issues
are solvable.
>
>>Yes and the redundancy is really nice to have. If the glider was not
>>capable of climbing on one I'd agree with you that one engine is
>>desirable but what is the point of designing around an engine that
>>isn't readily available with lots of operating history?
>Completely true. If we MUST use two because of
>marketing/availability/testing reasons
>then fine. Two in the hand is better than none in the bush. But
>accepting a sub-optimal design instead of making some extra phone
>calls means somebody else is gonna compete with you later, at
>a better price offering reduced maintenance/complexity...

Until he has a customer have an engine failure right after takeoff.
>
>>The packaging
>>of two is also easier.
>Boy I gotta strongly disagree with that.
>Installing, testing, wiring, instrumenting, fueling,
>operating, shutting down, diagnosing in flight, etc.
>for two engines is wholly different than one.
>There's a reason 727s have three crewmembers instead of one,
>and it isn't because of the complexity of the passengers
>or so the Captain can take a nap...

The 727 was designed in the early 60's. Even 747s with 4 engines don't
carry FE's anymore.

We are talking something that weighs 5 pounds. Installing and mounting
it isn't that difficult. Check out the model jet websites.
>
>>I've seen and heard the R/C model jets fly. They aren't that noisy at
>>all. Two smaller engines over the wingroots actually shields the
>>people on the ground from much of the noise.
>
>My comment about noise meaning you may get banned from the gliderport
>was tongue in cheek. Here's the ;) that should have been there...
>
>>Taxiing is still going to be problematical but then very few existing
>>self launchers taxi well(as opposed to Stemme's, Katanas etc and even
>>they would have trouble at our airport.
>>
>>I've got some time in the Jet Caproni about 20 years ago and I wasn't
>>that impressed. When I last flew in it 10 years ago the owner had
>>figured it out and it was good. We are talking the same sort of thrust
>>weight for a 400Kg glider(most 15/18m gliders) with two AMT 450's.
>
>>Mike Borgelt
>
>Yes, I'd very much like to see taxi capability. A short wingspan and
>light weight like a Sparrowhawk is excellent for this turbine.
>The extra stuff to make it taxi well would sell it to the
>biggest market, "power pilots," with the best success.

You would need to check the fuel consumption at reduced power. You
might get a nasty surprise. The taxi to the strip might have fuel
consumption comparable to driving an M1A2 the same distance.

I can easily live without the taxi ability. I'm looking forward to the
Ventus Ca17.6TJ(that's TwinJet)

Mike Borgelt

Kirk Stant

January 12th 04, 10:27 PM

Eric Greenwell > wrote in message >...
yet? Or did I miss something. Just curious.
>
> It was registered in the Experimetal class, just like your LS-6.

Curious; my LS6 is registered Experimental - Racing, but it is a
certified glider in Europe (JAR?) so I have to comply with all the
normal certified aircraft procedures. For example, I can't do annuals
on it myself.

As I understand it, the Sparrowhawk is not certified anywhere, just
registered Experimental - as in homebuilt experimental, where you can
do all the work yourself on it. I didn't know you could build and
sell aircraft that way - I thought they had to be kit built.

So it really isn't "just like my LS6", as I see it.

Or do I have all this certification stuff wrong? I havn't really read
up on it much.

Again, just curious; if the thing is safe to fly then it's all just
legal bull**** anyway...

I probably cant make it down to Estrella soon, hope it makes it to
Turf soon.

Kirk

Eric Greenwell

January 13th 04, 12:30 AM

Mike Borgelt wrote:

>>Yes, I'd very much like to see taxi capability. A short wingspan and
>>light weight like a Sparrowhawk is excellent for this turbine.
>>The extra stuff to make it taxi well would sell it to the
>>biggest market, "power pilots," with the best success.
>
>
> You would need to check the fuel consumption at reduced power. You
> might get a nasty surprise. The taxi to the strip might have fuel
> consumption comparable to driving an M1A2 the same distance.
>
> I can easily live without the taxi ability. I'm looking forward to the
> Ventus Ca17.6TJ(that's TwinJet)

I love being able to taxi in my ASH 26 E, but the alternative is to push
a 850 lb glider to the end of the runway. If it were a turbine powered
SparrowHawk, it'd be less 200 pounds, and pushing it down to the end
wouldn't be any worse than just walking down there. Seriously, it is so
much easier to push, it's not an issue, it's just walking. I could do
without the taxi ability to avoid carrying a large of amount of fuel to
do the taxi.

About 80% of my flights have only one engine use, a climb to ~2000' agl.
The rest have another engine start, and 15% have a typical run time of
less than 10 minutes. About 3% can be as much as 20 minutes additional
run time, and the last 2% haven't exceeded 40 minutes (total of 45
minutes for the flight). I can easily avoid that 2% and be happy with 30
minutes of fuel at climb power.

What do these things use for fuel? Do we need to land at airports with
Jet A to refuel? Or a town with a hobby shop and model airplanes?
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Washington State
USA

Eric Greenwell

January 13th 04, 12:44 AM

Kirk Stant wrote:

> Eric Greenwell > wrote in message >...
>
>>It was registered in the Experimetal class, just like your LS-6.
>
>
> Curious; my LS6 is registered Experimental - Racing, but it is a
> certified glider in Europe (JAR?) so I have to comply with all the
> normal certified aircraft procedures.

Actually, you don't: "Experimental" gives you some leeway than
"certified" doesn't.

> For example, I can't do annuals
> on it myself.

Your glider doesn't get an "annual", but a "condition inspection" since
it is experimental. You and I don't get to do the condition inspections
(my glider is "experimental" also) because we didn't build the aircraft,
like one in the experimental-amatuer built category.

>
> As I understand it, the Sparrowhawk is not certified anywhere, just
> registered Experimental - as in homebuilt experimental, where you can
> do all the work yourself on it. I didn't know you could build and
> sell aircraft that way - I thought they had to be kit built.
>
> So it really isn't "just like my LS6", as I see it.

The Russia AC-4 and AC-5M (for example) aren't certified, either, and
are licensed in the US in the "Experimental" category (racing and
exhibition, I assume). My ASH 26 E wasn't certified anywhere (not US,
not Germany) when I licensed it, either. A year or so later, it did
receive it's US certification, and I can convert to that category if I
wish to do so.

>
> Or do I have all this certification stuff wrong? I havn't really read
> up on it much.

It's confusing, all right.

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Washington State
USA

Mark James Boyd

January 13th 04, 02:31 AM

Mike,

Let's face it: you just WANT two engines. It isn't
a matter of design or complexity or fuel or cost; you just WANT
two little turbines on your glider. It looked really cool
and it sounds neat and you want TWO. Nothing wrong with that...
:P

Mike Borgelt > wrote:
>
>Even the jet Caproni was fly by wire for engine management. These
>engines already come with automatic electronic controls. Not a heck of
>a lot of complexity.
>
>They simply are not available yet. Two smaller turbines are and have
>some advantages and I beleive aren't likely to cost significantly more
>than one large one.
>>
>>>solved(and a good argument for two engines)
>>
>>>plus with two you really aren't going to fail to get at least one
>>>running to avoid an outlanding.
>>
>AMT450 or the AMT1500/1700. Redundancy may indeed be very nice to
>have.
>>
>The little engines are used in R/C models. Obviously the heat issues
>are solvable.
>>
>>>Yes and the redundancy is really nice to have. If the glider was not
>>>capable of climbing on one I'd agree with you that one engine is
>>>desirable but what is the point of designing around an engine that
>>>isn't readily available with lots of operating history?
>
>Until he has a customer have an engine failure right after takeoff.
>>
>>>The packaging
>>>of two is also easier.
>
>We are talking something that weighs 5 pounds. Installing and mounting
>it isn't that difficult. Check out the model jet websites.
>>
>>>Mike Borgelt
>>

>You would need to check the fuel consumption at reduced power. You
>might get a nasty surprise. The taxi to the strip might have fuel
>consumption comparable to driving an M1A2 the same distance.

Two gallons per mile? $4 to taxi to the runway? I'm fine with
that. My whole premise in this design was that 1/5 of the fuel
efficiency of a two-stroke is worth the enormous other benefits
(including 1/5 the parts count for the engine). Wasting fuel is
a feature, not a disadvantage in my mind. $10 extra a launch
in fuel is better than sending the testy ASH-26 engine
back to the factory for six months (talk to Bill Gawthrop).

Mark James Boyd

January 13th 04, 02:38 AM

Eric Greenwell > wrote:

>I love being able to taxi in my ASH 26 E, but the alternative is to push
>a 850 lb glider to the end of the runway. If it were a turbine powered
>SparrowHawk, it'd be less 200 pounds, and pushing it down to the end
>wouldn't be any worse than just walking down there. Seriously, it is so
>much easier to push, it's not an issue, it's just walking. I could do
>without the taxi ability to avoid carrying a large of amount of fuel to
>do the taxi.

An excellent point. A reflective vest and one could simply
walk the glider to the runway.

>About 80% of my flights have only one engine use, a climb to ~2000' agl.
>The rest have another engine start, and 15% have a typical run time of
>less than 10 minutes. About 3% can be as much as 20 minutes additional
>run time, and the last 2% haven't exceeded 40 minutes (total of 45
>minutes for the flight). I can easily avoid that 2% and be happy with 30
>minutes of fuel at climb power.

Assuming sustained flight may only require 10-20 lbs of thrust at
best L/D, fuel consumption may be quite low when used as a
turbo. On the other hand, full power may provide startling (redline)
speeds with 80-200 lbs of thrust and a 400# gross weight.

>What do these things use for fuel? Do we need to land at airports with
>Jet A to refuel? Or a town with a hobby shop and model airplanes?

Jet A, and some other stuff. I think they may burn just about
anything: castor oil, alchohol, melted margarine, autogas,
avgas, jet A, diesel, etc. The real problem is if the fuel
has contaminants (margarine may be a BAD idea).
Don't quote me on the fuels they use, but the turbine
principle seems to have few fuel restrictions in theory...

>Eric Greenwell

Doug Taylor

January 13th 04, 04:11 AM

Whether an aircraft is certified outside the United States makes no
difference. It doesn't even make any difference if it is certified in
the United States. Anything can be registered as Experimental -
Racing. What one has to comply with are the operating limitations
(usually stapled to the pink special airworthiness certificate or
stuffed in the pocket with it - if you don't have this, you can't fly)
and an annual condition inspection. Since anything with a special
airworthiness certificate is not really airworthy ;o), only an A&P is
required for the condition inspection, not an IA, and my understanding
is that anyone can do other maintenance as long as whatever they do
would not be considered a major alteration. None of the manufacturers
service bulletins, etc. need to be complied with technically (although
it would be a good idea). I suppose the DAR or FAA inspector could
put a paragraph in the limitations requiring that the manufacturers
recommendations must be complied with, but I haven't seen anything
like that.

(Kirk Stant) wrote in message

> Curious; my LS6 is registered Experimental - Racing, but it is a
> certified glider in Europe (JAR?) so I have to comply with all the
> normal certified aircraft procedures. For example, I can't do annuals
> on it myself.
>
> As I understand it, the Sparrowhawk is not certified anywhere, just
> registered Experimental - as in homebuilt experimental, where you can
> do all the work yourself on it. I didn't know you could build and
> sell aircraft that way - I thought they had to be kit built.
>
> So it really isn't "just like my LS6", as I see it.
>
> Or do I have all this certification stuff wrong? I havn't really read
> up on it much.
>
> Again, just curious; if the thing is safe to fly then it's all just
> legal bull**** anyway...
>
> I probably cant make it down to Estrella soon, hope it makes it to
> Turf soon.
>
> Kirk

Tim Ward

January 13th 04, 04:26 AM

"Mark James Boyd" > wrote in message
news:4003668d$1@darkstar...
>
> Mike,
>
> Let's face it: you just WANT two engines. It isn't
> a matter of design or complexity or fuel or cost; you just WANT
> two little turbines on your glider. It looked really cool
> and it sounds neat and you want TWO. Nothing wrong with that...
> :P

Dude, let's face it, logging multi-engine turbine time _is_ cool!

Tim Ward

Eric Greenwell

January 13th 04, 05:00 AM

Mark James Boyd wrote:
$10 extra a launch
> in fuel is better than sending the testy ASH-26 engine
> back to the factory for six months (talk to Bill Gawthrop).

Puhleease... I'm sure Bill is testy about his engine (six months is too
long, I think), but the engine used in the ASH 26 E has a very good
record, at least equal to the Solo used in the other gliders (a better
record, in my opinion).
--
-----
change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

Kirk Stant

January 13th 04, 05:33 PM

(Bob Kuykendall) wrote in message >...
> Earlier, (Kirk Stant) wrote:
>
> > One question: how do you buy a factory-
> > built Sparrowhawk and register it if it
> > isn't certified yet?
>
> As Experimental, Racing or Experimental, Exhibition, just like an ASW-20.
>
> Bob K.

Disagree; there is a big difference between my LS6s
EXPERIMENTAL-RACING certificate and the Sparrowhawks (as I understand
it): My LS6 is certified by the German LBA (their FAA) in the Utility
category per JAR certification requirements, this is accepted by the
FAA with the caveat that it be registered EXPERIMENTAL RACING with a
few limitations - basically comply with the operating limitation
letter, and Annuals by an A&P. Otherwise, not much difference from an
Utility category certified glider.

The Sparrowhawh is not certified by anybody, just registered in the
EXPERIMENTAL-RACING or EXHIBITION category. (Am I correct on this?)

Back to the original question - is it sold as an ultralight (no
registration needed) - then the owner adds 6 lbs of instruments and
re-registers it in the EXPERIMENTAL category? Sneaky! You must have
a friendly FSDO in the neighborhood! Top marks in "working the
system".

(good FAA info at http://www1.faa.gov/certification/aircraft/Special_Airworthiness_Certificates_Experimental_Ca tegory_General.htm)

Please note that this isn't a slam of the glider, or of the way it is
registered, just trying to understand what is going on.

Kirk
bemused old-fashioned glider guider

Bob Kuykendall

January 14th 04, 12:25 AM

Earlier, (Kirk Stant) wrote:

> Disagree; there is a big difference
> between my LS6s EXPERIMENTAL-RACING
> certificate and the Sparrowhawks
> (as I understand it): My LS6 is
> certified by the German LBA (their
> FAA) in the Utility category per
> JAR certification requirements,
> this is accepted by the FAA with
> the caveat that it be registered
> EXPERIMENTAL RACING with a few
> limitations - basically comply with
> the operating limitation letter,
> and Annuals by an A&P. Otherwise,
> not much difference from an Utility
> category certified glider.

That does not match my understanding of 14 CFR parts 21 and 23. The
way I see it, there is no difference between an Experimental, Racing
special airworthiness certificate for a German LBA-certificated glider
and an Experimental, Racing special airworthiness certificate for a
not-type-certificated-anywhere Applebay Zuni. That's based on a survey
of 14 CFR Parts 21 and 23, on my own brief interactions with the FAA
while obtaining a revised Special Airworthiness certificate, and on my
conversations with George Applebay, who sold a couple dozen Zunis that
were operated under Experimental, Racing AW certificates.

However, I know enough logic to refrain from trying to prove a
negative. If you can demonstrate the "big difference," or even point
to where I can find it myself, I'd be much obliged. Really; that is
definitely something I need to be aware of. But otherwise, we'll have
to agree to disagree.

> Back to the original question - is it
> sold as an ultralight (no registration
> needed) - then the owner adds 6 lbs
> of instruments and re-registers it in
> the EXPERIMENTAL category? Sneaky!
> You must have a friendly FSDO in the
> neighborhood! Top marks in "working
> the system".

WWP can manufacture and sell SparrowHawks of any weight they want - it
is after all a free country. However, the owners of the heavy ones
have to obtain Special Airworthiness certificates for them just like
owners of ASW-20s, Russias, and Zunis.

Thanks, and best regards

Bob K.
http://www.hpaircraft.com/hp-24

Wayne Paul

January 14th 04, 01:00 AM

Additional support of Bob's positions can be found in the 20 or so Concept
70s that were built in the early 1970s. (The first one flew in 1971.)

Wayne
http://www.soaridaho.com/Schreder

"Bob Kuykendall" > wrote in message
om...
> Earlier, (Kirk Stant) wrote:
>
> > Disagree; there is a big difference
> > between my LS6s EXPERIMENTAL-RACING
> > certificate and the Sparrowhawks
> > (as I understand it): My LS6 is
> > certified by the German LBA (their
> > FAA) in the Utility category per
> > JAR certification requirements,
> > this is accepted by the FAA with
> > the caveat that it be registered
> > EXPERIMENTAL RACING with a few
> > limitations - basically comply with
> > the operating limitation letter,
> > and Annuals by an A&P. Otherwise,
> > not much difference from an Utility
> > category certified glider.
>
> That does not match my understanding of 14 CFR parts 21 and 23. The
> way I see it, there is no difference between an Experimental, Racing
> special airworthiness certificate for a German LBA-certificated glider
> and an Experimental, Racing special airworthiness certificate for a
> not-type-certificated-anywhere Applebay Zuni. That's based on a survey
> of 14 CFR Parts 21 and 23, on my own brief interactions with the FAA
> while obtaining a revised Special Airworthiness certificate, and on my
> conversations with George Applebay, who sold a couple dozen Zunis that
> were operated under Experimental, Racing AW certificates.
>
> However, I know enough logic to refrain from trying to prove a
> negative. If you can demonstrate the "big difference," or even point
> to where I can find it myself, I'd be much obliged. Really; that is
> definitely something I need to be aware of. But otherwise, we'll have
> to agree to disagree.
>
> > Back to the original question - is it
> > sold as an ultralight (no registration
> > needed) - then the owner adds 6 lbs
> > of instruments and re-registers it in
> > the EXPERIMENTAL category? Sneaky!
> > You must have a friendly FSDO in the
> > neighborhood! Top marks in "working
> > the system".
>
> WWP can manufacture and sell SparrowHawks of any weight they want - it
> is after all a free country. However, the owners of the heavy ones
> have to obtain Special Airworthiness certificates for them just like
> owners of ASW-20s, Russias, and Zunis.
>
> Thanks, and best regards
>
> Bob K.
> http://www.hpaircraft.com/hp-24

Jim Phoenix

January 14th 04, 01:54 PM

"Wayne Paul" > wrote in message >...
> Additional support of Bob's positions can be found in the 20 or so Concept
> 70s that were built in the early 1970s. (The first one flew in 1971.)
>
> Wayne
> http://www.soaridaho.com/Schreder
>
>
>
> "Bob Kuykendall" > wrote in message
> om...
> > Earlier, (Kirk Stant) wrote:
> >
> > > Disagree; there is a big difference
> > > between my LS6s EXPERIMENTAL-RACING
> > > certificate and the Sparrowhawks
> > > (as I understand it): My LS6 is
> > > certified by the German LBA (their
> > > FAA) in the Utility category per
> > > JAR certification requirements,
> > > this is accepted by the FAA with
> > > the caveat that it be registered
> > > EXPERIMENTAL RACING with a few
> > > limitations - basically comply with
> > > the operating limitation letter,
> > > and Annuals by an A&P. Otherwise,
> > > not much difference from an Utility
> > > category certified glider.
> >
> > That does not match my understanding of 14 CFR parts 21 and 23. The
> > way I see it, there is no difference between an Experimental, Racing
> > special airworthiness certificate for a German LBA-certificated glider
> > and an Experimental, Racing special airworthiness certificate for a
> > not-type-certificated-anywhere Applebay Zuni. That's based on a survey
> > of 14 CFR Parts 21 and 23, on my own brief interactions with the FAA
> > while obtaining a revised Special Airworthiness certificate, and on my
> > conversations with George Applebay, who sold a couple dozen Zunis that
> > were operated under Experimental, Racing AW certificates.
> >
> > However, I know enough logic to refrain from trying to prove a
> > negative. If you can demonstrate the "big difference," or even point
> > to where I can find it myself, I'd be much obliged. Really; that is
> > definitely something I need to be aware of. But otherwise, we'll have
> > to agree to disagree.
> >
> > > Back to the original question - is it
> > > sold as an ultralight (no registration
> > > needed) - then the owner adds 6 lbs
> > > of instruments and re-registers it in
> > > the EXPERIMENTAL category? Sneaky!
> > > You must have a friendly FSDO in the
> > > neighborhood! Top marks in "working
> > > the system".
> >
> > WWP can manufacture and sell SparrowHawks of any weight they want - it
> > is after all a free country. However, the owners of the heavy ones
> > have to obtain Special Airworthiness certificates for them just like
> > owners of ASW-20s, Russias, and Zunis.
> >
> > Thanks, and best regards
> >
> > Bob K.
> > http://www.hpaircraft.com/hp-24

Bob's right, and the answer to all these sort of experimental
certification questions lie in the FAA Order 8130.2E. Fascinating
reading and available free on-line at faa.gov

Don't all rush there at once, youll overload the server!

Jim

Kirk Stant

January 14th 04, 02:00 PM

(Bob Kuykendall) wrote in message >...

> That does not match my understanding of 14 CFR parts 21 and 23. The
> way I see it, there is no difference between an Experimental, Racing
> special airworthiness certificate for a German LBA-certificated glider
> and an Experimental, Racing special airworthiness certificate for a
> not-type-certificated-anywhere Applebay Zuni. That's based on a survey
> of 14 CFR Parts 21 and 23, on my own brief interactions with the FAA
> while obtaining a revised Special Airworthiness certificate, and on my
> conversations with George Applebay, who sold a couple dozen Zunis that
> were operated under Experimental, Racing AW certificates.
>
> However, I know enough logic to refrain from trying to prove a
> negative. If you can demonstrate the "big difference," or even point
> to where I can find it myself, I'd be much obliged. Really; that is
> definitely something I need to be aware of. But otherwise, we'll have
> to agree to disagree.

> WWP can manufacture and sell SparrowHawks of any weight they want - it
> is after all a free country. However, the owners of the heavy ones
> have to obtain Special Airworthiness certificates for them just like
> owners of ASW-20s, Russias, and Zunis.
>
> Thanks, and best regards
>
> Bob K.
> http://www.hpaircraft.com/hp-24

OK, I see your point - It's just a bit surprising given all the hoopla
that airplane manufacturers put our about the "huge cost of
certification", etc. Then why does any builder of sport aircraft
worry about certification? Why aren't there a bunch of factory-built
RV-8s running around with EXPERIMENTAL on them? Does it have to do
with commercial use of the plane? Insurance? Airplane vs Glider? I
think I may have to dig a little to see what is in the regs.

I will stand by my opinion that there is a difference between a glider
that is certified in one country but not in the US being given an
EXPERIMENTAL, and a glider built anywhere without any certification
(FAA, JAR, whatever) getting that same EXPERIMENTAL - the difference
is the actual certification testing conducted on the glider - but in
practical terms it doesn't (and shouldn't!) mean much, assuming the
manufacturer does his job right. Of course, there can always be cases
like the American Falcon and Spirit; remember that fiasco?.

Fun discussion. Anything that increases my understanding of our
simple aviation rules is helpful...

Regards,

Kirk

Cliff Hilty

January 14th 04, 02:54 PM

Kirk Stant wrote
'Fun discussion. Anything that increases my understanding
of our
simple aviation rules is helpful...'

Interestingly I have one of the last special Air worthness
certificates that the FSDO's were willing to give without
special conditions! Such as where you can fly. Mine
just states 'Exhibition and Racing' with no restrictions
on where!
And when I lost it I was able to get the exact replacement
a few years ago. Must have been my lucky day!

Cliff

Mark James Boyd

January 14th 04, 05:08 PM

>OK, I see your point - It's just a bit surprising given all the hoopla
>that airplane manufacturers put our about the "huge cost of
>certification", etc. Then why does any builder of sport aircraft
>worry about certification? Why aren't there a bunch of factory-built
>RV-8s running around with EXPERIMENTAL on them? Does it have to do
>with commercial use of the plane? Insurance? Airplane vs Glider? I
>think I may have to dig a little to see what is in the regs.

I'd guess that Van's doesn't wholly manufacture aircraft for liability
reasons more than anything else.

In the case of the foriegn built gliders, they already have a
manufacturer that can be sued, so that isn't the thing stopping them.
Since the glider (PW6 for example) is already to JAR standards,
there isn't much additional cost for US certification.
And the upside is that they can sell to commercial, for profit
operators in the US.

As far as why US builders of sport aircraft care about certification,
there are big differences in "hassle" and cost passed on to the
customer between an ultralight, a "light-sport aircraft," an
experimental, or a standard aircraft. And there are continuing
costs associated with the ongoing maintenance/pilot
licensing standards.

I suspect forcing the customer to accept more
costs is less marketable than giving the customer the option of
certifying the aircraft in one of the more restrictive categories,
after purchase, at their leisure.

January 14th 04, 06:30 PM

"Kirk Stant" > wrote in message
om...
> (Bob Kuykendall) wrote in message
>...
>
>
> OK, I see your point - It's just a bit surprising given all the hoopla
> that airplane manufacturers put our about the "huge cost of
> certification", etc. Then why does any builder of sport aircraft
> worry about certification? Why aren't there a bunch of factory-built
> RV-8s running around with EXPERIMENTAL on them? Does it have to do
> with commercial use of the plane? Insurance? Airplane vs Glider? I
> think I may have to dig a little to see what is in the regs.
>
Because RV-8's are not generally used for exhibition and racing. There are
other categories for EXPERIMENTAL certification, like "Marketing Demo",
"Development", and "Amateur/Home Built" but these would also be unlikely to
apply to a typical factory built RV-8 (or Cezzna, or whatever). You can't
get an EXPERIMENTAL certificate just because you (as a manufacture) don't
want to bother with certification. This is one of the reasons that I am
amused by the vocal "anti-racing" crowd that occasionally pipes up; if it
wasn't for sailplane racing the basis of the EXPERIMENTAL certifications of
most US gliders would be questionable.

mm

Tim Mara

January 14th 04, 06:36 PM

OK.I have stayed out of this discussion and probably should still.....
but I will agree with everyone (almost) to soem degree
Yes....the experimental certificates are "experimental certificates"
regardless of who or how they are made...means that as far as the FAA is
concerned, you are taking additional risks at your own choosing, that's fine
with the FAA...same goes for ultra-lites, the FAA more or less steps away
from these and says if it's under the weights ect you can go it alone at
your own risk..just don't mix in with the FAA air traffic control
system...much the same as with homebuilt.....you have extra risks and some
loss of airspace use, FAA systems and obligations....not much different
than operating an ATV or snowmobile on private lands...
Now as for Experimental based on (foreign certificated aircraft), in order
to be certified in almost any country there are far more stringent rules and
requirements. You need to use approved materials and follow far more
rigorous testing procedures.....build and test to destruction components and
so on...so there is likely a lot of benefit to owning (and paying extra for)
this type.
Certificated aircraft and those recognized in for instance the USA and the
country where they were built and certified is even more stringent, meaning
you have to meet or exceed the requirements in both courtiers to gain this
certification, you also have no special restrictions on airspace regarding
the certificate and you are also part of the FAA notification system for
AD's (not always a bad thing to know when someone else's part failed) that
you will not get if it's experimental in any category. So there is a lot
more the manufacturers must do to comply and support their aircraft and the
system....
Boils down to this.....anyone could design and sell an air vehicle and save
themselves thousands of dollars or euros and probably find buyers....buyers
that may in fact be willing to accept, or at least say they do accept the
responsibility themselves...you decide for yourself if there really is a
difference...prudence says there probably is...
tim

"Kirk Stant" > wrote in message > >
> > Bob K.
> > http://www.hpaircraft.com/hp-24
>
> OK, I see your point - It's just a bit surprising given all the hoopla
> that airplane manufacturers put our about the "huge cost of
> certification", etc. Then why does any builder of sport aircraft
> worry about certification? Why aren't there a bunch of factory-built
> RV-8s running around with EXPERIMENTAL on them? Does it have to do
> with commercial use of the plane? Insurance? Airplane vs Glider? I
> think I may have to dig a little to see what is in the regs.
>
> I will stand by my opinion that there is a difference between a glider
> that is certified in one country but not in the US being given an
> EXPERIMENTAL, and a glider built anywhere without any certification
> (FAA, JAR, whatever) getting that same EXPERIMENTAL - the difference
> is the actual certification testing conducted on the glider - but in
> practical terms it doesn't (and shouldn't!) mean much, assuming the
> manufacturer does his job right. Of course, there can always be cases
> like the American Falcon and Spirit; remember that fiasco?.
>
> Fun discussion. Anything that increases my understanding of our
> simple aviation rules is helpful...
>
> Regards,
>
> Kirk

Bob Kuykendall

January 14th 04, 06:44 PM

Earlier, (Kirk Stant) wrote:

> OK, I see your point - It's just a bit surprising given all the hoopla
> that airplane manufacturers put our about the "huge cost of
> certification", etc. Then why does any builder of sport aircraft
> worry about certification? Why aren't there a bunch of factory-built
> RV-8s running around with EXPERIMENTAL on them? Does it have to do
> with commercial use of the plane? Insurance? Airplane vs Glider? I
> think I may have to dig a little to see what is in the regs.

That is an interesting issue, and I'm glad you raised it.

First off, the typical operating limitations of Experimental,
Racing/Exhibition are usually quite different from those of
Experimental, Amateur-built. With Amateur-built experimentals, once
you've flown off the initial 25- or 40-hour test period, the typical
operating limitations are generally almost as liberal as for a type
certificated airplane. You can operate over congested areas, you can
fly with passengers, and it's OK to wander around on the typical $100
hamburger hunting trip. There's none of that "program letter"
business. And to get one of those certificates, all you have to do is
demonstrate that the major portion of the aircraft was built for the
purposes of recreation and education.

However, the operating limitations of Experimental, Racing and
Experimental, Exhibition are typically more restrictive. For a full
list of what you'd typically encounter, see this Jim Pratt Web page:

http://www.provide.net/~pratt1/ambuilt/exhibyak.htm

For a powered airplane, those restrictions can be quite onerous, and
take a lot of fun out of owning the airplane. However, for a glider
they virtually disappear into the inherent limitations of soaring
flight:

* Most soaring operations take place in the middle of nowhere, where
there are few congested areas or airspace issues. And if you do have
to deviate into a congested area to find a landing spot, well, that's
an operation required for landing so it's (probably) OK.

* It's not too farfetched to posit that every soaring flight is a
proficiency run for some future contest. Glider contests are, after
all, pretty common, and ASW-20s and similar are often flown in
contests. I can imagine that it would be good if you flew in a contest
every few years, but I've known of a few people with such gliders who
don't.

* You've got that whole "program letter" thing, but if you can soar to
the edge of a 300 nautical mile operating cylinder, you're doing
great. And if you've done your letter right, even that's probably not
a problem. From what I've seen, glider program letters get relatively
light scrutiny.

* Since most sport sailplanes have only one seat, all the verbiage
about passengers and required crewmembers goes right out the window.

Thanks again, and best regards to all

Bob K.
http://www.hpaircraft.com

Larry Goddard

January 18th 04, 12:34 PM

Mark James Boyd wrote:

> <snip>
> The heat on the tail scares me though. Hmmm...how do we
> get rid of the glider tail? ;)

Duhhhhh... run the jet engine a little too long!? :-)

January 19th 04, 01:59 AM

The Sparrow Hawk is built under paet 103 which states a ultra light
glider is one which wieghs less than 155Lbs, now if you want to go and
compete at a regional which requires that all sailplanes have a
airworthiness certificate you can certify the SparrowHawk as
Experimental Air Racing because of the "need" required for racing. As
what was said earlier the limitations are attached to the pink ticket.
The limitations usually state that you hve a profiency area of 300
miles from your airport, now if you want to go somewhere else you can
just as long as you notify your local FSDO, maybe you just want to try
for a badge, any excuse will work, it will be the insurance company
asking the questions when you make the claim, if you have a
Experimental Air Racing and do not have any limitions attached you
better find them because you are not legal without them. Other wise
you fly as a utralight, nothing wrong with that.

"mm" > wrote in message >...
> "Kirk Stant" > wrote in message
> om...
> > (Bob Kuykendall) wrote in message
> >...
> >
> >
> > OK, I see your point - It's just a bit surprising given all the hoopla
> > that airplane manufacturers put our about the "huge cost of
> > certification", etc. Then why does any builder of sport aircraft
> > worry about certification? Why aren't there a bunch of factory-built
> > RV-8s running around with EXPERIMENTAL on them? Does it have to do
> > with commercial use of the plane? Insurance? Airplane vs Glider? I
> > think I may have to dig a little to see what is in the regs.
> >
> Because RV-8's are not generally used for exhibition and racing. There are
> other categories for EXPERIMENTAL certification, like "Marketing Demo",
> "Development", and "Amateur/Home Built" but these would also be unlikely to
> apply to a typical factory built RV-8 (or Cezzna, or whatever). You can't
> get an EXPERIMENTAL certificate just because you (as a manufacture) don't
> want to bother with certification. This is one of the reasons that I am
> amused by the vocal "anti-racing" crowd that occasionally pipes up; if it
> wasn't for sailplane racing the basis of the EXPERIMENTAL certifications of
> most US gliders would be questionable.
>
> mm