Primary Glider Drawings

[[email protected]]

To All:

As promised, I've began posting drawings of primary glider(s). You
will find them in PRIMARY_GLIDERS Group, in the FILES archive, in the
Folder 'The Northrup Primary Glider.' So far I've only posted a few.
The others will be posted as time -- and my medical condition --
permits.

The drawings are in DeltaCAD's native format; the file suffix is .dc.
DeltaCAD will give you a free but time-crippled copy of their
software. It is about 6megabytes and will run on any WINDOWS system
from 95 on up. Most of the drawings are of fittings. The main
advantage in using a CAD format is that the drawings may be printed
full-scale, allowing them to be used as patterns.

I believe I have drawings for five different primaries but so far I've
only found the Northrup and the SG-38. These use a wooden fuselage.
Other primaries use welded steel tubing.

'Northrup' is a seed company. A member of the Northrup family
imported a primary glider after seeing them being flown in Europe
(circa 1929) and 'Northrup' became synonymous with 'primary glider.'
The drawings depict one of the earliest configurations of the primary
glider, in which the wings are wire-braced. Later versions have a
strut-braced wing.

NORTHROP refers to John Northrop, the American engineer best known for
his flying wings.

-R.S.Hoover

[Tech Support]

On Sat, 4 Oct 2008 09:30:25 -0700 (PDT), "
> wrote:

>To All:
>
>As promised, I've began posting drawings of primary glider(s). You
>will find them in PRIMARY_GLIDERS Group, in the FILES archive, in the
>Folder 'The Northrup Primary Glider.' So far I've only posted a few.
>The others will be posted as time -- and my medical condition --
>permits.
>
>The drawings are in DeltaCAD's native format; the file suffix is .dc.
>DeltaCAD will give you a free but time-crippled copy of their
>software. It is about 6megabytes and will run on any WINDOWS system
>from 95 on up. Most of the drawings are of fittings. The main
>advantage in using a CAD format is that the drawings may be printed
>full-scale, allowing them to be used as patterns.
>
>I believe I have drawings for five different primaries but so far I've
>only found the Northrup and the SG-38. These use a wooden fuselage.
>Other primaries use welded steel tubing.
>
>'Northrup' is a seed company. A member of the Northrup family
>imported a primary glider after seeing them being flown in Europe
>(circa 1929) and 'Northrup' became synonymous with 'primary glider.'
>The drawings depict one of the earliest configurations of the primary
>glider, in which the wings are wire-braced. Later versions have a
>strut-braced wing.
>
>NORTHROP refers to John Northrop, the American engineer best known for
>his flying wings.
>
>-R.S.Hoover
************************************************** ************************

Veeduber

What would it take to convert a primary into a basic soaring machine
(35+ to 1)?. I know sitting in open would be a high drag problem
but.......maybe a very light none structual wood frame cloth covered
to stream line fuselage?

Could a machine be made very cheap and quick this way to permit
soaring local around the air patch?

Also designed to pull (or fold) the wings in a few minutes (Solo) and
load to haul home for storage (and work/repair) in the garage?

To continue with a War Story.

I had a young Japanese man working for me in Japan. In discussion with
him he said he was in pilot training when war ended.

He said that the initial training was in primary gliders and that the
instructor stood on the welded steel tubing just behind the pilot in
training. The instructor wore the classical Japanese socks, like they
wore with 'zories', and gripped the tubing between the big toe and
first toe and held on to a vertical piece of the tubing.

Since the instructor couldn't reach the controls in front of pilot, he
gave voice instructions over the shoulder until he got off and let the
pilot go solo.

Launch was typical V of shock cord which two groups would hold and run
down the hill to extend. When they had stretched the shock cord
enough, the glider would be released and launched down the hill just a
few feet off the ground as sink rate and slope of hill was about the
same.

As was typical of Primary Glider flying, all the pilots had to help
launch and pull the gliders back up the hill.


Big John

[Vaughn Simon]

<Tech Support> wrote in message
...

> What would it take to convert a primary into a basic soaring machine
> (35+ to 1)?.

Start over and design a completly different machine with a completely
different mission! Most true training gliders have an L/D of considerably less
than 35 to one.

> I know sitting in open would be a high drag problem
> but.......maybe a very light none structual wood frame cloth covered
> to stream line fuselage?

The PW-2 Gapa is about as far as one can go with the primary concept. It is
capable of thermaling and extended (albeit local) flights given the right
conditions, but has a stated L/D of only 12.5.
http://www.soaravenal.com/gapa.htm I almost had access to one once. My
employer ended up with a nice one, but never got it licensed.

Vaughn

[Wayne Paul]

> Veeduber
>
> What would it take to convert a primary into a basic soaring machine
> (35+ to 1)?. I know sitting in open would be a high drag problem
> but.......maybe a very light none structual wood frame cloth covered
> to stream line fuselage?
>
> Could a machine be made very cheap and quick this way to permit
> soaring local around the air patch?
>
> Also designed to pull (or fold) the wings in a few minutes (Solo) and
> load to haul home for storage (and work/repair) in the garage?
>

Big John,

35 to 1 and open cockpit don't coexist. Light weigh does not improve glider
ratio. In order to get anything near 35 to 1 in a homebuilt you must build
something like my Schreder HP-14.
(http://www.soaridaho.com/Schreder/HP-14/N990/N990.html)

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

[Bill Daniels]

"Wayne Paul" > wrote in message
...
>> Veeduber
>>
>> What would it take to convert a primary into a basic soaring machine
>> (35+ to 1)?. I know sitting in open would be a high drag problem
>> but.......maybe a very light none structual wood frame cloth covered
>> to stream line fuselage?
>>
>> Could a machine be made very cheap and quick this way to permit
>> soaring local around the air patch?
>>
>> Also designed to pull (or fold) the wings in a few minutes (Solo) and
>> load to haul home for storage (and work/repair) in the garage?
>>
>
> Big John,
>
> 35 to 1 and open cockpit don't coexist. Light weigh does not improve
> glider ratio. In order to get anything near 35 to 1 in a homebuilt you
> must build something like my Schreder HP-14.
> (http://www.soaridaho.com/Schreder/HP-14/N990/N990.html)
>
> Wayne
> http://www.soaridaho.com/Schreder
>
>
Another option is to take a look at the SLA gliders like the Sparrowhawk.
These have an airframe weight of less than 200 pounds. In some cases the
glider weighs less than the pilot! In spite of their light and relatively
simple construction, they exhibit impressive performance in excess of 30:1.
See: http://www.windward-performance.com/

I doubt that they will ever exceed the 40:1 common among the larger 15 meter
gliders but they're a far better solution than a 'primary glider'.

[Peter Dohm]

"Bill Daniels" <bildan@comcast-dot-net> wrote in message
. ..
>
> "Wayne Paul" > wrote in message
> ...
>>> Veeduber
>>>
>>> What would it take to convert a primary into a basic soaring machine
>>> (35+ to 1)?. I know sitting in open would be a high drag problem
>>> but.......maybe a very light none structual wood frame cloth covered
>>> to stream line fuselage?
>>>
>>> Could a machine be made very cheap and quick this way to permit
>>> soaring local around the air patch?
>>>
>>> Also designed to pull (or fold) the wings in a few minutes (Solo) and
>>> load to haul home for storage (and work/repair) in the garage?
>>>
>>
>> Big John,
>>
>> 35 to 1 and open cockpit don't coexist. Light weigh does not improve
>> glider ratio. In order to get anything near 35 to 1 in a homebuilt you
>> must build something like my Schreder HP-14.
>> (http://www.soaridaho.com/Schreder/HP-14/N990/N990.html)
>>
>> Wayne
>> http://www.soaridaho.com/Schreder
>>
>>
> Another option is to take a look at the SLA gliders like the Sparrowhawk.
> These have an airframe weight of less than 200 pounds. In some cases the
> glider weighs less than the pilot! In spite of their light and relatively
> simple construction, they exhibit impressive performance in excess of
> 30:1. See: http://www.windward-performance.com/
>
> I doubt that they will ever exceed the 40:1 common among the larger 15
> meter gliders but they're a far better solution than a 'primary glider'.
>
Well, I really liked what I saw and read, and might even fit in it quite
comfortably.

However, although I should probably leave this to the experienced glider
pilots, I think that it is probably two steps up from the primary glider. I
also thing that the primary glider, or a modern analog with a little better
occupant protection (especially legs), still has a very usefull place as a
true basic trainer. Personally, having only one glider demo ride many years
ago, I would prefer to start with a much lower L/D--especially for the first
few solo areo-tows!

Sorry about the lack of hubris, but self preservation does have some merit.
Peter

[Bill Daniels]

"Peter Dohm" > wrote in message
. ..
> "Bill Daniels" <bildan@comcast-dot-net> wrote in message
> . ..
>>
>> "Wayne Paul" > wrote in message
>> ...
>>>> Veeduber
>>>>
>>>> What would it take to convert a primary into a basic soaring machine
>>>> (35+ to 1)?. I know sitting in open would be a high drag problem
>>>> but.......maybe a very light none structual wood frame cloth covered
>>>> to stream line fuselage?
>>>>
>>>> Could a machine be made very cheap and quick this way to permit
>>>> soaring local around the air patch?
>>>>
>>>> Also designed to pull (or fold) the wings in a few minutes (Solo) and
>>>> load to haul home for storage (and work/repair) in the garage?
>>>>
>>>
>>> Big John,
>>>
>>> 35 to 1 and open cockpit don't coexist. Light weigh does not improve
>>> glider ratio. In order to get anything near 35 to 1 in a homebuilt you
>>> must build something like my Schreder HP-14.
>>> (http://www.soaridaho.com/Schreder/HP-14/N990/N990.html)
>>>
>>> Wayne
>>> http://www.soaridaho.com/Schreder
>>>
>>>
>> Another option is to take a look at the SLA gliders like the Sparrowhawk.
>> These have an airframe weight of less than 200 pounds. In some cases the
>> glider weighs less than the pilot! In spite of their light and
>> relatively simple construction, they exhibit impressive performance in
>> excess of 30:1. See: http://www.windward-performance.com/
>>
>> I doubt that they will ever exceed the 40:1 common among the larger 15
>> meter gliders but they're a far better solution than a 'primary glider'.
>>
> Well, I really liked what I saw and read, and might even fit in it quite
> comfortably.
>
> However, although I should probably leave this to the experienced glider
> pilots, I think that it is probably two steps up from the primary glider.
> I also thing that the primary glider, or a modern analog with a little
> better occupant protection (especially legs), still has a very usefull
> place as a true basic trainer. Personally, having only one glider demo
> ride many years ago, I would prefer to start with a much lower
> L/D--especially for the first few solo areo-tows!
>
> Sorry about the lack of hubris, but self preservation does have some
> merit.
> Peter
>

Let me throw in a slightly controversial idea.

Low L/D, taken in isolation, offers no benefit whatsoever in a trainer. In
fact, higher L/D is a safety feature that gets an inexperienced pilot back
to the runway after a bad judgement call. In spite of this, there is an
instinctive reaction among most glider pilots to inversely relate L/D and
safe handling qualities.

I would claim they are directly related. A glider carefully engineered for
great handling and occupant protection will also have a good L/D. As an
example, I would offer the excellent Schleicher ASK-21 as well as several
other modern composite trainers.

The little Sparrowhawk is not really a trainer. It's a single seater that
requires a pilot to approach it with considerable training in his logbook.
It is, however, an excellent minimalist design.

"Primary gliders" were an expedient developed in an environment that lacked
adequate two-seat trainers. They were abandoned with great relief as soon
as usable 2-seater trainers became available. Today, there are a great
number of excellent 2-seat trainers and qualified instructors. Only a fool
would try to learn flying in a "Primary".

[Wayne Paul]

"Bill Daniels" <bildan@comcast-dot-net> wrote in message
. ..
> Let me throw in a slightly controversial idea.
>
> Low L/D, taken in isolation, offers no benefit whatsoever in a trainer.
> In fact, higher L/D is a safety feature that gets an inexperienced pilot
> back to the runway after a bad judgement call. In spite of this, there is
> an instinctive reaction among most glider pilots to inversely relate L/D
> and safe handling qualities.
>
> I would claim they are directly related. A glider carefully engineered
> for great handling and occupant protection will also have a good L/D. As
> an example, I would offer the excellent Schleicher ASK-21 as well as
> several other modern composite trainers.
>
> The little Sparrowhawk is not really a trainer. It's a single seater that
> requires a pilot to approach it with considerable training in his logbook.
> It is, however, an excellent minimalist design.
>
> "Primary gliders" were an expedient developed in an environment that
> lacked adequate two-seat trainers. They were abandoned with great relief
> as soon as usable 2-seater trainers became available. Today, there are a
> great number of excellent 2-seat trainers and qualified instructors. Only
> a fool would try to learn flying in a "Primary".
>
Bill,

I have read your posts here and rec.aviation.soaring. To date I have never
disagreed with your opinions. Here again, I am in total agreement.

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

[Vaughn Simon]

"Bill Daniels" <bildan@comcast-dot-net> wrote in message
. ..
> Low L/D, taken in isolation, offers no benefit whatsoever in a trainer. In
> fact, higher L/D is a safety feature that gets an inexperienced pilot back to
> the runway after a bad judgement call.

I MOSTLY agree (see below) ...

>In spite of this, there is an instinctive reaction among most glider pilots to
>inversely relate L/D and safe handling qualities.

A high L/D implies a very slippery airframe. Unless any high L/D glider
trainer is very carefully engineered, a moment's inattention to any nose-down
attitude could quickly result in airspeeds beyond Vne.

> Only a fool would try to learn flying in a "Primary".

I don't know that I go quite that far, but as I have said before, I would not
recommend a primary as a flight training aircraft. That said, building one
might be a great learning experience at the EAA chapter level and flying it
would be a great activity for the annual chapter picnic.

Vaughn

[Ron Wanttaja]

On Sun, 5 Oct 2008 09:18:21 -0600, "Bill Daniels" <bildan@comcast-dot-net>
wrote:

> I would claim they are directly related. A glider carefully engineered for
> great handling and occupant protection will also have a good L/D.

Bill, I don't have a dog in this hunt, but: Unless you're using a different
definition of "occupant protection" than I am, I disagree. Adding a steel crash
cage to a glider cockpit will increase occupant protection, but has a negative
effect on the aircraft weight without improving the aerodynamic performance.

If your intent was more along the lines "occupant encapsulation" (e.g.,
enclosing the pilot to minimize aerodynamic drag), then we're in agreement. but
it would be possible to put the pilot in an eggshell that would achieve the
aerodynamics without significantly improving the crash protection....

Ron Wanttaja

[Bill Daniels]

"Vaughn Simon" > wrote in message
...
>
> "Bill Daniels" <bildan@comcast-dot-net> wrote in message
> . ..
>> Low L/D, taken in isolation, offers no benefit whatsoever in a trainer.
>> In fact, higher L/D is a safety feature that gets an inexperienced pilot
>> back to the runway after a bad judgement call.
>
> I MOSTLY agree (see below) ...
>
>>In spite of this, there is an instinctive reaction among most glider
>>pilots to inversely relate L/D and safe handling qualities.
>
> A high L/D implies a very slippery airframe. Unless any high L/D glider
> trainer is very carefully engineered, a moment's inattention to any
> nose-down attitude could quickly result in airspeeds beyond Vne.
>
>> Only a fool would try to learn flying in a "Primary".
>
> I don't know that I go quite that far, but as I have said before, I
> would not recommend a primary as a flight training aircraft. That said,
> building one might be a great learning experience at the EAA chapter level
> and flying it would be a great activity for the annual chapter picnic.
>
> Vaughn

I actually have quite a bit of experience transitioning limited experience
pilots to high performance gliders. The most recent is a new partner in my
Nimbus whose only previous experience was in a 28:1 Blanik L-13. More often
it's a 2-33 pilot in a Duo Discus. My club trains ab-initio students in a
45:1 DG505.

Airspeed control difficulties in slippery gliders is often greatly
exaggerated.

Yes, they will have problems with airspeed control for a few minutes but not
extremely so. Mostly it's letting the airspeed oscillate in the 45 - 60
knot range while circling. They also tend to get a little fast on
approaches. Once they get a good handle on pitch attitude the problem goes
away. These "uber performance" gliders tend to have very effective
airbrakes with which to control excessive speed. Nothing dangerous here.

Letting airspeed increase unintentionally in a high L/D glider is no worse
than the inability to recover airspeed quickly in a low L'D glider.

[Bill Daniels]

"Ron Wanttaja" > wrote in message
...
> On Sun, 5 Oct 2008 09:18:21 -0600, "Bill Daniels" <bildan@comcast-dot-net>
> wrote:
>
>> I would claim they are directly related. A glider carefully engineered
>> for
>> great handling and occupant protection will also have a good L/D.
>
> Bill, I don't have a dog in this hunt, but: Unless you're using a
> different
> definition of "occupant protection" than I am, I disagree. Adding a steel
> crash
> cage to a glider cockpit will increase occupant protection, but has a
> negative
> effect on the aircraft weight without improving the aerodynamic
> performance.
>
> If your intent was more along the lines "occupant encapsulation" (e.g.,
> enclosing the pilot to minimize aerodynamic drag), then we're in
> agreement. but
> it would be possible to put the pilot in an eggshell that would achieve
> the
> aerodynamics without significantly improving the crash protection....
>
> Ron Wanttaja

I think steel tube structures are way overrated for "occupant protection" as
compared to carbon/Kevlar cockpits on modern composite gliders. Race car
builders abandoned steel tube "birdcages" for carbon/kevlar tubs a long time
ago for safety reasons. You'll never look at steel tube structure the same
way after you've seen a folded tube sever a leg artery.

For the most part, steel tube cages are limited to wing attachment/landing
gear structures in modern gliders.

Bill D

[Andreas Maurer[_1_]]

On Sun, 05 Oct 2008 16:32:12 GMT, "Vaughn Simon"
> wrote:

> A high L/D implies a very slippery airframe. Unless any high L/D glider
>trainer is very carefully engineered, a moment's inattention to any nose-down
>attitude could quickly result in airspeeds beyond Vne.

I wish that sentence was true........ :)
Even an 58:1 ship at its maximum wing load requires significant
nose-down attitude to reach its Vne... unfortunately.
>
>> Only a fool would try to learn flying in a "Primary".
>
> I don't know that I go quite that far, but as I have said before, I would not
>recommend a primary as a flight training aircraft. That said, building one
>might be a great learning experience at the EAA chapter level and flying it
>would be a great activity for the annual chapter picnic.

Rather design and buil something that doesn't become boring after falf
a year.... :)

Bye
Andreas

[Ron Wanttaja]

On Sun, 5 Oct 2008 13:33:05 -0600, "Bill Daniels" <bildan@comcast-dot-net>
wrote:

>
> "Ron Wanttaja" > wrote in message
> ...
> > On Sun, 5 Oct 2008 09:18:21 -0600, "Bill Daniels" <bildan@comcast-dot-net>
> > wrote:
> >
> >> I would claim they are directly related. A glider carefully engineered
> >> for great handling and occupant protection will also have a good L/D.
> >
> > Bill, I don't have a dog in this hunt, but: Unless you're using a
> > different definition of "occupant protection" than I am, I disagree.
> > Adding a steel crash cage to a glider cockpit will increase occupant
> > protection, but has a negative effect on the aircraft weight
> > without improving the aerodynamic performance.
>
> I think steel tube structures are way overrated for "occupant protection" as
> compared to carbon/Kevlar cockpits on modern composite gliders. Race car
> builders abandoned steel tube "birdcages" for carbon/kevlar tubs a long time
> ago for safety reasons. You'll never look at steel tube structure the same
> way after you've seen a folded tube sever a leg artery.

You're missing my point, Bill. Whether steel tube or kevlar, occupant
protection does not contribute to L/D, as you seemed to claim. Wrapping an
eggshell around the pilot will give good aerodynamics, but better occupant
protection will weigh more and hence reduce performance.

Ron Wanttaja

[Tech Support]

Sure nice to have so many comments that are mostly relevant to thread
and beginners glider.

I was thinking about a wing that would support a decently high L/D and
a simple enclosure around pilot to reduce his flat plate drag, built
on a primary glider fuselage frame.

Build time 500 hours or less and transportable home. I'm in my high
80's and don't have 'time' left to build a 10 year project.

Would even consider adding a couple of chain saw engines for self
launch vs aero tow. To keep simple just use for launch and a retract
system with no restart in air. Simple and light weight.

Idea would be to keep very simple, cheap and light. Glider counter
part to LSA in GA.

Big John
************************************************** **


On Sat, 04 Oct 2008 13:35:29 -0500, Tech Support <> wrote:

>On Sat, 4 Oct 2008 09:30:25 -0700 (PDT), "
> wrote:
>
>>To All:
>>
>>As promised, I've began posting drawings of primary glider(s). You
>>will find them in PRIMARY_GLIDERS Group, in the FILES archive, in the
>>Folder 'The Northrup Primary Glider.' So far I've only posted a few.
>>The others will be posted as time -- and my medical condition --
>>permits.
>>
>>The drawings are in DeltaCAD's native format; the file suffix is .dc.
>>DeltaCAD will give you a free but time-crippled copy of their
>>software. It is about 6megabytes and will run on any WINDOWS system
>>from 95 on up. Most of the drawings are of fittings. The main
>>advantage in using a CAD format is that the drawings may be printed
>>full-scale, allowing them to be used as patterns.
>>
>>I believe I have drawings for five different primaries but so far I've
>>only found the Northrup and the SG-38. These use a wooden fuselage.
>>Other primaries use welded steel tubing.
>>
>>'Northrup' is a seed company. A member of the Northrup family
>>imported a primary glider after seeing them being flown in Europe
>>(circa 1929) and 'Northrup' became synonymous with 'primary glider.'
>>The drawings depict one of the earliest configurations of the primary
>>glider, in which the wings are wire-braced. Later versions have a
>>strut-braced wing.
>>
>>NORTHROP refers to John Northrop, the American engineer best known for
>>his flying wings.
>>
>>-R.S.Hoover
>************************************************** ************************
>
>Veeduber
>
>What would it take to convert a primary into a basic soaring machine
>(35+ to 1)?. I know sitting in open would be a high drag problem
>but.......maybe a very light none structual wood frame cloth covered
>to stream line fuselage?
>
>Could a machine be made very cheap and quick this way to permit
>soaring local around the air patch?
>
>Also designed to pull (or fold) the wings in a few minutes (Solo) and
>load to haul home for storage (and work/repair) in the garage?
>
>To continue with a War Story.
>
>I had a young Japanese man working for me in Japan. In discussion with
>him he said he was in pilot training when war ended.
>
>He said that the initial training was in primary gliders and that the
>instructor stood on the welded steel tubing just behind the pilot in
>training. The instructor wore the classical Japanese socks, like they
>wore with 'zories', and gripped the tubing between the big toe and
>first toe and held on to a vertical piece of the tubing.
>
>Since the instructor couldn't reach the controls in front of pilot, he
>gave voice instructions over the shoulder until he got off and let the
>pilot go solo.
>
>Launch was typical V of shock cord which two groups would hold and run
>down the hill to extend. When they had stretched the shock cord
>enough, the glider would be released and launched down the hill just a
>few feet off the ground as sink rate and slope of hill was about the
>same.
>
>As was typical of Primary Glider flying, all the pilots had to help
>launch and pull the gliders back up the hill.
>
>
>Big John

[Bill Daniels]

"Ron Wanttaja" > wrote in message
...
> On Sun, 5 Oct 2008 13:33:05 -0600, "Bill Daniels" <bildan@comcast-dot-net>
> wrote:
>
>>
>> "Ron Wanttaja" > wrote in message
>> ...
>> > On Sun, 5 Oct 2008 09:18:21 -0600, "Bill Daniels"
>> > <bildan@comcast-dot-net>
>> > wrote:
>> >
>> >> I would claim they are directly related. A glider carefully
>> >> engineered
>> >> for great handling and occupant protection will also have a good L/D.
>> >
>> > Bill, I don't have a dog in this hunt, but: Unless you're using a
>> > different definition of "occupant protection" than I am, I disagree.
>> > Adding a steel crash cage to a glider cockpit will increase occupant
>> > protection, but has a negative effect on the aircraft weight
>> > without improving the aerodynamic performance.
>>
>> I think steel tube structures are way overrated for "occupant protection"
>> as
>> compared to carbon/Kevlar cockpits on modern composite gliders. Race car
>> builders abandoned steel tube "birdcages" for carbon/kevlar tubs a long
>> time
>> ago for safety reasons. You'll never look at steel tube structure the
>> same
>> way after you've seen a folded tube sever a leg artery.
>
> You're missing my point, Bill. Whether steel tube or kevlar, occupant
> protection does not contribute to L/D, as you seemed to claim. Wrapping
> an
> eggshell around the pilot will give good aerodynamics, but better occupant
> protection will weigh more and hence reduce performance.
>
> Ron Wanttaja

Weight in a glider is a double edged sword and never simple. In fact, it
can add to L/D. For example, my Nimbus 2C has an L/D max of 47:1 at 1000
pounds and 49:1 at 1433 pounds. The difference in L/D max is due to a
higher Reynolds number at the higher best L/D airspeed with the higher
weight.

That extra weight is ballast water in wing tanks. In any but the weakest
weather, that ballast dramatically increases performance. This is shown
most clearly at 100 Kts where the 1000lb GW L/D is 22.3:1 and the 1433lb GW
L/D is 31:1. But, of course, structural weight is not jetisonable as is
water ballast.

But that wasn't really my point. It was that good engineering directed at
crashworthiness is an investment in design excellence which is also likely,
but not assuredly, to increase performance. At least the two aren't
mutually exclusive. That's particularly true when the cockpit structure is
molded carbon/Kevlar which can be of any shape and might as well be the best
aerodynamic one. As near as I can determine, the latest crashworthy
cockpits don't weight any more than the old ones and they are actually
lighter than steel tubes.

Bill D

[Peter Dohm]

"Bill Daniels" <bildan@comcast-dot-net> wrote in message
...
>
> "Ron Wanttaja" > wrote in message
> ...
>> On Sun, 5 Oct 2008 13:33:05 -0600, "Bill Daniels"
>> <bildan@comcast-dot-net>
>> wrote:
>>
>>>
>>> "Ron Wanttaja" > wrote in message
>>> ...
>>> > On Sun, 5 Oct 2008 09:18:21 -0600, "Bill Daniels"
>>> > <bildan@comcast-dot-net>
>>> > wrote:
>>> >
>>> >> I would claim they are directly related. A glider carefully
>>> >> engineered
>>> >> for great handling and occupant protection will also have a good L/D.
>>> >
>>> > Bill, I don't have a dog in this hunt, but: Unless you're using a
>>> > different definition of "occupant protection" than I am, I disagree.
>>> > Adding a steel crash cage to a glider cockpit will increase occupant
>>> > protection, but has a negative effect on the aircraft weight
>>> > without improving the aerodynamic performance.
>>>
>>> I think steel tube structures are way overrated for "occupant
>>> protection" as
>>> compared to carbon/Kevlar cockpits on modern composite gliders. Race
>>> car
>>> builders abandoned steel tube "birdcages" for carbon/kevlar tubs a long
>>> time
>>> ago for safety reasons. You'll never look at steel tube structure the
>>> same
>>> way after you've seen a folded tube sever a leg artery.
>>
>> You're missing my point, Bill. Whether steel tube or kevlar, occupant
>> protection does not contribute to L/D, as you seemed to claim. Wrapping
>> an
>> eggshell around the pilot will give good aerodynamics, but better
>> occupant
>> protection will weigh more and hence reduce performance.
>>
>> Ron Wanttaja
>
> Weight in a glider is a double edged sword and never simple. In fact, it
> can add to L/D. For example, my Nimbus 2C has an L/D max of 47:1 at 1000
> pounds and 49:1 at 1433 pounds. The difference in L/D max is due to a
> higher Reynolds number at the higher best L/D airspeed with the higher
> weight.
>
> That extra weight is ballast water in wing tanks. In any but the weakest
> weather, that ballast dramatically increases performance. This is shown
> most clearly at 100 Kts where the 1000lb GW L/D is 22.3:1 and the 1433lb
> GW L/D is 31:1. But, of course, structural weight is not jetisonable as
> is water ballast.
>
> But that wasn't really my point. It was that good engineering directed at
> crashworthiness is an investment in design excellence which is also
> likely, but not assuredly, to increase performance. At least the two
> aren't mutually exclusive. That's particularly true when the cockpit
> structure is molded carbon/Kevlar which can be of any shape and might as
> well be the best aerodynamic one. As near as I can determine, the latest
> crashworthy cockpits don't weight any more than the old ones and they are
> actually lighter than steel tubes.
>
> Bill D
>
I believe that you are correct in this, and that a kevlar capsule is a good
investment.

I have not researched the matter and could be wrong; but I strongly suspect
that a many, if not most, of the dissabling leg injuries in the old primary
gliders involved easily deflected collisions rather than "hitting a wall".

Peter

[Bill Daniels]

"Peter Dohm" > wrote in message
. ..
> "Bill Daniels" <bildan@comcast-dot-net> wrote in message
> ...
>>
>> "Ron Wanttaja" > wrote in message
>> ...
>>> On Sun, 5 Oct 2008 13:33:05 -0600, "Bill Daniels"
>>> <bildan@comcast-dot-net>
>>> wrote:
>>>
>>>>
>>>> "Ron Wanttaja" > wrote in message
>>>> ...
>>>> > On Sun, 5 Oct 2008 09:18:21 -0600, "Bill Daniels"
>>>> > <bildan@comcast-dot-net>
>>>> > wrote:
>>>> >
>>>> >> I would claim they are directly related. A glider carefully
>>>> >> engineered
>>>> >> for great handling and occupant protection will also have a good
>>>> >> L/D.
>>>> >
>>>> > Bill, I don't have a dog in this hunt, but: Unless you're using a
>>>> > different definition of "occupant protection" than I am, I disagree.
>>>> > Adding a steel crash cage to a glider cockpit will increase occupant
>>>> > protection, but has a negative effect on the aircraft weight
>>>> > without improving the aerodynamic performance.
>>>>
>>>> I think steel tube structures are way overrated for "occupant
>>>> protection" as
>>>> compared to carbon/Kevlar cockpits on modern composite gliders. Race
>>>> car
>>>> builders abandoned steel tube "birdcages" for carbon/kevlar tubs a long
>>>> time
>>>> ago for safety reasons. You'll never look at steel tube structure the
>>>> same
>>>> way after you've seen a folded tube sever a leg artery.
>>>
>>> You're missing my point, Bill. Whether steel tube or kevlar, occupant
>>> protection does not contribute to L/D, as you seemed to claim. Wrapping
>>> an
>>> eggshell around the pilot will give good aerodynamics, but better
>>> occupant
>>> protection will weigh more and hence reduce performance.
>>>
>>> Ron Wanttaja
>>
>> Weight in a glider is a double edged sword and never simple. In fact, it
>> can add to L/D. For example, my Nimbus 2C has an L/D max of 47:1 at 1000
>> pounds and 49:1 at 1433 pounds. The difference in L/D max is due to a
>> higher Reynolds number at the higher best L/D airspeed with the higher
>> weight.
>>
>> That extra weight is ballast water in wing tanks. In any but the weakest
>> weather, that ballast dramatically increases performance. This is shown
>> most clearly at 100 Kts where the 1000lb GW L/D is 22.3:1 and the 1433lb
>> GW L/D is 31:1. But, of course, structural weight is not jetisonable as
>> is water ballast.
>>
>> But that wasn't really my point. It was that good engineering directed
>> at crashworthiness is an investment in design excellence which is also
>> likely, but not assuredly, to increase performance. At least the two
>> aren't mutually exclusive. That's particularly true when the cockpit
>> structure is molded carbon/Kevlar which can be of any shape and might as
>> well be the best aerodynamic one. As near as I can determine, the latest
>> crashworthy cockpits don't weight any more than the old ones and they are
>> actually lighter than steel tubes.
>>
>> Bill D
>>
> I believe that you are correct in this, and that a kevlar capsule is a
> good investment.
>
> I have not researched the matter and could be wrong; but I strongly
> suspect that a many, if not most, of the dissabling leg injuries in the
> old primary gliders involved easily deflected collisions rather than
> "hitting a wall".
>
> Peter
Most likely.

I know of one accident in a Schweizer 1-26A (tube and fabric) where an off
field landing resulted in a stick coming through the nose fabric severing a
leg artery. The pilot bled to death before he could get out of the cockpit.
I guess you can tell that I have no love of tube and fabric gliders.

Bill D

[Michael Henry[_2_]]

What great timing for this subject to come up!

On Saturday I attended a course "How to design an aircraft" given by
Bill Whitney who designed, or contributed to the design, of:
* The Whitney Boomerang (http://www.dwaviation.com/),
* The Australian Light Wing (http://www.lightwing.com.au/),
* The Seabird Seeker (http://www.seabirdaviation.com/),

....and about a dozen other aircraft. This was an exceptionally
interesting course and Bill had lots of stories to tell about aircraft
design. He has a very strong interest in crashworthiness and he
dedicates an entire chapter of his notes to this topic, along with
pictures and diagrams from the crash testing of the Boomerang. Given all
this it might be of interest to you to read his views on the subject.

In his notes he says: "Having been to many accident scenes, it is my
view that by far the best structure is the tubular steel fuselage
framework."

He continues: "Aircraft constructed of sheet metal also work reasonably
well provided there are some heavy extrusions going forward from the
pilot's seat to the firewall. In addition, fasteners with significant
tensile strength are required because heavily buckled panels place
significant prying loads on rivets tending to pop them out of their
holes. Thus use of 3/32"dia. or even 1/8" dia. rivets should be avoided
in the nose structure of the fuselage and 5/32" or even 3/16" rivets
should be used.

"In my experience, the poorest performers of all are composite
structures. Crashworthiness can be built into these structures but
almost never is. Building in crashworthiness can be achieved by building
in heavy floor-fuselage side angles or heavy hat sections into the
fuselage inner surface. These added sections will be exposed to
compression so they should be made of uni-directional fibreglass running
fore and aft with some diagonally laid laminates to transfer shear
loads. These sections will need to be reasonably thick noting that local
buckling or crippling is heavily dependent on thickness.

"Timber structures are also very poor performers."

(Whew! I hope this falls under "fair use"!)

Bill stressed the importance of designing a structure which would
"preserve the living space" in a crash. He mentioned the example of a
Jabiru crash where the aircraft failed to do this and fragmented into
small pieces.

Interesting stuff!


Bill Daniels wrote:
> I think steel tube structures are way overrated for "occupant protection" as
> compared to carbon/Kevlar cockpits on modern composite gliders. Race car
> builders abandoned steel tube "birdcages" for carbon/kevlar tubs a long time
> ago for safety reasons. You'll never look at steel tube structure the same
> way after you've seen a folded tube sever a leg artery.
>
> For the most part, steel tube cages are limited to wing attachment/landing
> gear structures in modern gliders.
>
> Bill D
>
>

[Michael Henry[_2_]]

Tech Support wrote:
> Sure nice to have so many comments that are mostly relevant to thread
> and beginners glider.

Hear hear!!!

> I was thinking about a wing that would support a decently high L/D and
> a simple enclosure around pilot to reduce his flat plate drag, built
> on a primary glider fuselage frame.
>
> Build time 500 hours or less and transportable home. I'm in my high
> 80's and don't have 'time' left to build a 10 year project.

What you're describing is the Compact 110 (defunct):

http://home.ptd.net/~jlbaker/compact110.htm

....or the ULF-1:

http://www.eel.de/english/ulf-1_description.htm

[[email protected]]

On Oct 4, 11:35*am, Tech Support <> wrote:

> Veeduber
>
> What would it take to convert a primary into a basic soaring machine
> (35+ to 1)?
-----------------------------------------------------------------------
Dear John,

I don't know. But I DO know you're comparing apples to
orangutans :-) The subject is Primary Gliders. Their poor glide
ratio -- typically about 8:1 -- is by DESIGN. That is what's needed
to fulfill their mission, which is to expose a fledgling pilot to 3-
axis controls and introduce them to the mechanics of landing.

You would probably find the syllabus used by early flight-training
programs to be of considerable interest.

-R.S.Hoover

[Tech Support]

On Mon, 06 Oct 2008 13:34:46 +1000, Michael Henry
> wrote:

>Tech Support wrote:
>> Sure nice to have so many comments that are mostly relevant to thread
>> and beginners glider.
>
>Hear hear!!!
>
>> I was thinking about a wing that would support a decently high L/D and
>> a simple enclosure around pilot to reduce his flat plate drag, built
>> on a primary glider fuselage frame.
>>
>> Build time 500 hours or less and transportable home. I'm in my high
>> 80's and don't have 'time' left to build a 10 year project.
>
>What you're describing is the Compact 110 (defunct):
>
>http://home.ptd.net/~jlbaker/compact110.htm
>
>...or the ULF-1:
>
>http://www.eel.de/english/ulf-1_description.htm
************************************************** ***********************

Michael

In the ball park of what I was talking about. Will take to bed with me
and look and think on data of those who have gone before me.

Tnx

Big John

[cavelamb himself[_4_]]

Which also linked to . . .

the Sandlin Bug
(Basic Ultralight Glider)

http://home.att.net/~m--sandlin/bug.htm

[RST Engineering]

Perhaps nothing except the basic fundamental understanding of WHAT SNIP
MEANS.

>
> Veeduber
>
> What would it take to convert a primary into a basic soaring machine
> (35+ to 1)?.

[RST Engineering]

Perhaps nothing except the basic fundamental understanding of WHAT SNIP
MEANS.


--
"It is the mark of an educated mind to be able to entertain a thought
without accepting it."
--Aristotle

[RST Engineering]

Perhaps nothing except the basic fundamental understanding of WHAT SNIP
MEANS.


> 35 to 1 and open cockpit don't coexist. Light weigh does not improve
> glider ratio. In order to get anything near 35 to 1 in a homebuilt you
> must build something like my Schreder HP-14.
> (http://www.soaridaho.com/Schreder/HP-14/N990/N990.html)
>
> Wayne
> http://www.soaridaho.com/Schreder
>
>
>
>

[Peter Dohm]

"Bill Daniels" <bildan@comcast-dot-net> wrote in message
. ..
>
> "Peter Dohm" > wrote in message
> . ..
>> "Bill Daniels" <bildan@comcast-dot-net> wrote in message
>> ...
>>> Weight in a glider is a double edged sword and never simple. In fact,
>>> it can add to L/D. For example, my Nimbus 2C has an L/D max of 47:1 at
>>> 1000 pounds and 49:1 at 1433 pounds. The difference in L/D max is due
>>> to a higher Reynolds number at the higher best L/D airspeed with the
>>> higher weight.
>>>
>>> That extra weight is ballast water in wing tanks. In any but the
>>> weakest weather, that ballast dramatically increases performance. This
>>> is shown most clearly at 100 Kts where the 1000lb GW L/D is 22.3:1 and
>>> the 1433lb GW L/D is 31:1. But, of course, structural weight is not
>>> jetisonable as is water ballast.
>>>
>>> But that wasn't really my point. It was that good engineering directed
>>> at crashworthiness is an investment in design excellence which is also
>>> likely, but not assuredly, to increase performance. At least the two
>>> aren't mutually exclusive. That's particularly true when the cockpit
>>> structure is molded carbon/Kevlar which can be of any shape and might as
>>> well be the best aerodynamic one. As near as I can determine, the
>>> latest crashworthy cockpits don't weight any more than the old ones and
>>> they are actually lighter than steel tubes.
>>>
>>> Bill D
>>>
>> I believe that you are correct in this, and that a kevlar capsule is a
>> good investment.
>>
>> I have not researched the matter and could be wrong; but I strongly
>> suspect that a many, if not most, of the dissabling leg injuries in the
>> old primary gliders involved easily deflected collisions rather than
>> "hitting a wall".
>>
>> Peter
> Most likely.
>
> I know of one accident in a Schweizer 1-26A (tube and fabric) where an off
> field landing resulted in a stick coming through the nose fabric severing
> a leg artery. The pilot bled to death before he could get out of the
> cockpit. I guess you can tell that I have no love of tube and fabric
> gliders.
>
> Bill D
>
This is an extreme case of the same problem that concerns me: Intrusion of
"brush" in the course of an off field landing. Obviously, in this
particular case, the shrubbery involved must have appeared to be soft enough
to be deflected by the tube and fabric structure; but the general problem
must have been nearly epidemic with the completely open seating areas of the
primary gliders.

Nothing can ever eliminate the occasional encounter with a stronger and/or
sharper than expected solid object; but a slightly flexible kevlar based
composite capsule could be a great improvement. The March racing cars used
a kevlar based capsule system about 30 years ago with considerable
success--although their earliest attempts were heavy and less than
competitive, and some developement was required.

AFAIK, kevlar has a high tensile strenght, but does not bond to the resins
in which it might be encapslated. Therefore, it will extrude under load.
That makes it a good to excellent material for safety structures and a
generally poor material for heavy load bearing structures.

Peter

[Tim Ward[_1_]]

"Bill Daniels" <bildan@comcast-dot-net> wrote in message
. ..
<snippage>
> Let me throw in a slightly controversial idea.
>
> Low L/D, taken in isolation, offers no benefit whatsoever in a trainer.
In
> fact, higher L/D is a safety feature that gets an inexperienced pilot back
> to the runway after a bad judgement call. In spite of this, there is an
> instinctive reaction among most glider pilots to inversely relate L/D and
> safe handling qualities.

In a soaring environment, I think you're right. But that is not the
environment veeduber is proposing.

He's proposing a cheap "hook" to capture the attention of teenagers.
Teenagers who might not have two grand or so to shell out for glider
lessons, but might well have some sweat equity to invest in building
something that actually flies.

For this target group, it has to be something that goes together pretty
quickly. If it takes a thousand hours of construction, it isn't likely to
get started, let alone completed.

For veeduber's purposes, I think he will have achieved part of his goal if
it gets even half built. Kids will be using their heads and their hands to
solve problems.

For this environment, it's not performance that counts, but energy. With a
fairly draggy airframe, you can limit the amount of energy available to
damage the pilot.

Somewhere on Mike Sandlin's site, he remarks on this, limiting the energy by
how far up the training hill you drag the glider.

<snippage>

> "Primary gliders" were an expedient developed in an environment that
lacked
> adequate two-seat trainers. They were abandoned with great relief as soon
> as usable 2-seater trainers became available. Today, there are a great
> number of excellent 2-seat trainers and qualified instructors. Only a
fool
> would try to learn flying in a "Primary".

I can't entirely disagree, but people learn to fly hang gliders, with
similar performance limitations, every day.
There is some tandem instruction available, and that's good. But in
general, it's not the instruction process that kills people.
A two-place primary under 155 lbs might sneak in under USHGPA's tandem
exemption, here in the U.S. Maybe.


Tim Ward

[Tech Support]

On Sun, 5 Oct 2008 21:43:49 -0700 (PDT), "
> wrote:

>On Oct 4, 11:35*am, Tech Support <> wrote:
>
>> Veeduber
>>
>> What would it take to convert a primary into a basic soaring machine
>> (35+ to 1)?
>-----------------------------------------------------------------------
>Dear John,
>
>I don't know. But I DO know you're comparing apples to
>orangutans :-) The subject is Primary Gliders. Their poor glide
>ratio -- typically about 8:1 -- is by DESIGN. That is what's needed
>to fulfill their mission, which is to expose a fledgling pilot to 3-
>axis controls and introduce them to the mechanics of landing.
>
>You would probably find the syllabus used by early flight-training
>programs to be of considerable interest.
>
>-R.S.Hoover
************************************************** ***************************


Understand ur comments but intent of my original post was to get some
ideas on size and airfoil of a wing attached to a Primary Glider
fuselage with a minimual enclosure around pilot that would permit some
basic soaring. All on the cheap and rapid build.

Lots of ideas have been expessed that shot down some of my original
ideas and others that have given me clues on how to meet my original
objectives.

Tnx to all.

Y'all have a nice day and hope you get good news on ur health.

Big John

[Bill Daniels]

"Tim Ward" > wrote in message
...
>
> "Bill Daniels" <bildan@comcast-dot-net> wrote in message
> . ..
> <snippage>
>> Let me throw in a slightly controversial idea.
>>
>> Low L/D, taken in isolation, offers no benefit whatsoever in a trainer.
> In
>> fact, higher L/D is a safety feature that gets an inexperienced pilot
>> back
>> to the runway after a bad judgement call. In spite of this, there is an
>> instinctive reaction among most glider pilots to inversely relate L/D and
>> safe handling qualities.
>
> In a soaring environment, I think you're right. But that is not the
> environment veeduber is proposing.
>
> He's proposing a cheap "hook" to capture the attention of teenagers.
> Teenagers who might not have two grand or so to shell out for glider
> lessons, but might well have some sweat equity to invest in building
> something that actually flies.
>
> For this target group, it has to be something that goes together pretty
> quickly. If it takes a thousand hours of construction, it isn't likely
> to
> get started, let alone completed.
>
> For veeduber's purposes, I think he will have achieved part of his goal if
> it gets even half built. Kids will be using their heads and their hands
> to
> solve problems.
>
> For this environment, it's not performance that counts, but energy. With
> a
> fairly draggy airframe, you can limit the amount of energy available to
> damage the pilot.
>
> Somewhere on Mike Sandlin's site, he remarks on this, limiting the energy
> by
> how far up the training hill you drag the glider.
>
> <snippage>
>
>> "Primary gliders" were an expedient developed in an environment that
> lacked
>> adequate two-seat trainers. They were abandoned with great relief as
>> soon
>> as usable 2-seater trainers became available. Today, there are a great
>> number of excellent 2-seat trainers and qualified instructors. Only a
> fool
>> would try to learn flying in a "Primary".
>
> I can't entirely disagree, but people learn to fly hang gliders, with
> similar performance limitations, every day.
> There is some tandem instruction available, and that's good. But in
> general, it's not the instruction process that kills people.
> A two-place primary under 155 lbs might sneak in under USHGPA's tandem
> exemption, here in the U.S. Maybe.
>
>
> Tim Ward
>
>

OK, but don't build one, buy one. There are a few around. Take it out to a
hill or dry lake and try flying it. This is also done on occasion. What
you won't do is fly it two days in a row. One day will convince just about
anybody that primaries are a really bad idea.

Primary gliders are a huge amount of work to fly - expecially if you use the
traditional bungee launch method which is really the only safe way to fly
one. Aero tow or winch launch is terrfying in a primary - although this is
also done on occasion. (But rarely twice in a lifetime by the same pilot.)

To fly one as it was intended, you need a huge grassy slope that is slightly
shallower than the glide ratio of the primary. The bungee launch will get
the glider to just above stall speed a couple of feet above the ground. If
the pilot can hold the exact best L/D airspeed and keep it perfectly
coordinated, he will be rewarded with a glide of a couple of hundred yards -
maybe 30 seconds of airtime. If he deviates in any way from perfection, the
glider will quickly settle into the grass. If you have 15 - 20 knots of
wind up the slope, the instructor can run along side shouting instructions.
Then everybody gets to haul it back up the slope. All this exercise will
achieve about ten flights a day but it WILL get you in shape.
See: http://www.youtube.com/watch?v=B6-EeuEi-KY
See: http://www.youtube.com/watch?v=BgBJ52L-Rao

I have a better idea that fits well with the homebuilder ethic. Build a
winch.
See: http://groups.yahoo.com/group/winchengineer/files/

The really big cost in learning to fly gliders is aero tow. It averages
about $50 for a 15 minute flight. Add instructor and glider rental and it's
not unusual to see $250 and hour. Multi-engine training is cheaper.
Winches can reduce launch costs to $5 and glider training rates to ~$50/hr.
Certified glider trainers aren't expensive if you can keep the utilization
high.

And I GUARANTEE it attracts young people. You can't buy a ride like that at
Disneyland.
See: http://www.youtube.com/watch?v=UOp_EsplxDM

Bill Daniels

[cavelamb himself[_4_]]

Bill Daniels wrote:
>
> And I GUARANTEE it attracts young people. You can't buy a ride like that at
> Disneyland.
> See: http://www.youtube.com/watch?v=UOp_EsplxDM
>
> Bill Daniels
>
>

Unfortunately, the liability issue kills the whole thing before it can
even get off the ground.


--

Richard

(remove the X to email)

[Bill Daniels]

"cavelamb himself" > wrote in message
...
> Bill Daniels wrote:
>>
>> And I GUARANTEE it attracts young people. You can't buy a ride like that
>> at Disneyland.
>> See: http://www.youtube.com/watch?v=UOp_EsplxDM
>>
>> Bill Daniels
>>
>>
>
> Unfortunately, the liability issue kills the whole thing before it can
> even get off the ground.
>
>
> --
>
> Richard
>
> (remove the X to email)

What liability issue? Everything is insured.

This is done throughout the world as well as in the USA. The glider policy
covers the occupants and the airfield policy covers the winch. In fact, the
insurance is much cheaper than for an airplane. Although it is very
exciting, it isn't particularly dangerous if done by well trained pilots and
winch operators.

Bill Daniels

[Peter Dohm]

"Bill Daniels" <bildan@comcast-dot-net> wrote in message
. ..
>
> "cavelamb himself" > wrote in message
> ...
>> Bill Daniels wrote:
>>>
>>> And I GUARANTEE it attracts young people. You can't buy a ride like
>>> that at Disneyland.
>>> See: http://www.youtube.com/watch?v=UOp_EsplxDM
>>>
>>> Bill Daniels
>>>
>>>
>>
>> Unfortunately, the liability issue kills the whole thing before it can
>> even get off the ground.
>>
>>
>> --
>>
>> Richard
>>
>> (remove the X to email)
>
> What liability issue? Everything is insured.
>
> This is done throughout the world as well as in the USA. The glider
> policy covers the occupants and the airfield policy covers the winch. In
> fact, the insurance is much cheaper than for an airplane. Although it is
> very exciting, it isn't particularly dangerous if done by well trained
> pilots and winch operators.
>
> Bill Daniels
>
First, let me confess that my total actual experience in a glider was a
single flight in a 2 seat Blanik and was launched by aero-tow.

That said, and just looking at the mechanics of the thing, I suspect that a
winch is probably the safest way to launch a glider--at least in an area
where you don't need the extra altitude that an aero-tow can provide. So,
where applicable, and with proberly trained pilots as you pointed out, it
should be an ideal way to incorporate gliders into a Young Eagles program.
It seems to have all of the best elements: (1) just about as safe as it can
get, (2) just about as cheap as it can get, and (3) utterly fascinating for
kids from 8 to 80!

It might revive chapters and entire airports.

Peter

[Bill Daniels]

"Peter Dohm" > wrote in message
.. .
> "Bill Daniels" <bildan@comcast-dot-net> wrote in message
> . ..
>>
>> "cavelamb himself" > wrote in message
>> ...
>>> Bill Daniels wrote:
>>>>
>>>> And I GUARANTEE it attracts young people. You can't buy a ride like
>>>> that at Disneyland.
>>>> See: http://www.youtube.com/watch?v=UOp_EsplxDM
>>>>
>>>> Bill Daniels
>>>>
>>>>
>>>
>>> Unfortunately, the liability issue kills the whole thing before it can
>>> even get off the ground.
>>>
>>>
>>> --
>>>
>>> Richard
>>>
>>> (remove the X to email)
>>
>> What liability issue? Everything is insured.
>>
>> This is done throughout the world as well as in the USA. The glider
>> policy covers the occupants and the airfield policy covers the winch. In
>> fact, the insurance is much cheaper than for an airplane. Although it is
>> very exciting, it isn't particularly dangerous if done by well trained
>> pilots and winch operators.
>>
>> Bill Daniels
>>
> First, let me confess that my total actual experience in a glider was a
> single flight in a 2 seat Blanik and was launched by aero-tow.
>
> That said, and just looking at the mechanics of the thing, I suspect that
> a winch is probably the safest way to launch a glider--at least in an area
> where you don't need the extra altitude that an aero-tow can provide. So,
> where applicable, and with proberly trained pilots as you pointed out, it
> should be an ideal way to incorporate gliders into a Young Eagles program.
> It seems to have all of the best elements: (1) just about as safe as it
> can get, (2) just about as cheap as it can get, and (3) utterly
> fascinating for kids from 8 to 80!
>
> It might revive chapters and entire airports.
>
> Peter
>
The theoretical maximum height from a winch launch is half the initial rope
length. (4000' runway gets 2000' AGL) Most operations achieve at least 40%.
With most runways, this will be higher than auto tow. Of course, if you
have unlimited room like a huge dry lake, auto tow will get you higher.
Winch launches in Germany have reached 5400' AGL from a 10,000' runway.

[cavelamb himself[_4_]]

Bill Daniels wrote:

> "cavelamb himself" > wrote in message
> ...
>
>>Bill Daniels wrote:
>>
>>>And I GUARANTEE it attracts young people. You can't buy a ride like that
>>>at Disneyland.
>>>See: http://www.youtube.com/watch?v=UOp_EsplxDM
>>>
>>>Bill Daniels
>>>
>>>
>>
>>Unfortunately, the liability issue kills the whole thing before it can
>>even get off the ground.
>>
>>
>>--
>>
>>Richard
>>
>>(remove the X to email)
>
>
> What liability issue? Everything is insured.
>
> This is done throughout the world as well as in the USA. The glider policy
> covers the occupants and the airfield policy covers the winch. In fact, the
> insurance is much cheaper than for an airplane. Although it is very
> exciting, it isn't particularly dangerous if done by well trained pilots and
> winch operators.
>
> Bill Daniels
>
>

Sorry Bill, I was stlii thinking Primary Glider.

I doubt you could find anyone that would underwrite a solo training
glider.

Dual sailplanes, with instructor - or at least qualified pilot - aboard
might be another story entirely.
--

Richard

(remove the X to email)

[Peter Dohm]

"Bill Daniels" <bildan@comcast-dot-net> wrote in message
...
>
> "Peter Dohm" > wrote in message
> .. .
>> "Bill Daniels" <bildan@comcast-dot-net> wrote in message
>> . ..

>>>
>>> What liability issue? Everything is insured.
>>>
>>> This is done throughout the world as well as in the USA. The glider
>>> policy covers the occupants and the airfield policy covers the winch.
>>> In fact, the insurance is much cheaper than for an airplane. Although
>>> it is very exciting, it isn't particularly dangerous if done by well
>>> trained pilots and winch operators.
>>>
>>> Bill Daniels
>>>
>> First, let me confess that my total actual experience in a glider was a
>> single flight in a 2 seat Blanik and was launched by aero-tow.
>>
>> That said, and just looking at the mechanics of the thing, I suspect that
>> a winch is probably the safest way to launch a glider--at least in an
>> area where you don't need the extra altitude that an aero-tow can
>> provide. So, where applicable, and with proberly trained pilots as you
>> pointed out, it should be an ideal way to incorporate gliders into a
>> Young Eagles program. It seems to have all of the best elements: (1)
>> just about as safe as it can get, (2) just about as cheap as it can get,
>> and (3) utterly fascinating for kids from 8 to 80!
>>
>> It might revive chapters and entire airports.
>>
>> Peter
>>
> The theoretical maximum height from a winch launch is half the initial
> rope length. (4000' runway gets 2000' AGL) Most operations achieve at
> least 40%. With most runways, this will be higher than auto tow. Of
> course, if you have unlimited room like a huge dry lake, auto tow will get
> you higher. Winch launches in Germany have reached 5400' AGL from a
> 10,000' runway.
>
That's actually better than I thought it would be. I was thinking of an
initial rope length of 3000 to 4000 feet, and presumed a height of 1000 to
1200 feet compared to around 2000 feet for aero tow. So, it looks like
winch launching could be quite competitive, even in very flat country,
except for the need to release over the airport.

Peter

[Big John]

On Sun, 5 Oct 2008 23:37:22 -0700, "RST Engineering"
> wrote:

>Perhaps nothing except the basic fundamental understanding of WHAT SNIP
>MEANS.
>
>>
>> Veeduber
>>
>> What would it take to convert a primary into a basic soaring machine
>> (35+ to 1)?.
>
************************************

RST

Know what snip means but don't have the ability like you to know what
was said back in thread without reading it current. Sure wish I had
that ability and I'd know how election will come out.

Big John

[Ernest Christley]

Bill Daniels wrote:
> Primary gliders are a huge amount of work to fly - expecially if you use the
> traditional bungee launch method which is really the only safe way to fly
> one. Aero tow or winch launch is terrfying in a primary - although this is
> also done on occasion. (But rarely twice in a lifetime by the same pilot.)
>
> To fly one as it was intended, you need a huge grassy slope that is slightly
> shallower than the glide ratio of the primary. The bungee launch will get
> the glider to just above stall speed a couple of feet above the ground. If
> the pilot can hold the exact best L/D airspeed and keep it perfectly
> coordinated, he will be rewarded with a glide of a couple of hundred yards -
> maybe 30 seconds of airtime. If he deviates in any way from perfection, the
> glider will quickly settle into the grass. If you have 15 - 20 knots of
> wind up the slope, the instructor can run along side shouting instructions.
> Then everybody gets to haul it back up the slope. All this exercise will
> achieve about ten flights a day but it WILL get you in shape.

Bill, this is a good point, except veedubber was talking about using
these particular contraptions to attract young-uns. Now, I don't know
how it is where you live, but here in NC we get MAYBE one good snow a
year. These young-uns will bundle up till they look like balloons, then
go run up a snow covered hill for a slow bumpy ride down a shallow slope.

I could be wrong, but I'm just not seeing the physical exertion aspect
being a big detraction for the target group.