Schweizer 1-35 and other flapped sailplanes

[Jack]

I've seen several remarks lately in Soaring Magazine and on my home
club's internet forum about the characteristics of this particular
sailplane. Though not directly bashing this ship, comments made seem to
imply that it's a difficult or dangerous sailplane to fly. I think
that's wrong. Some of these comments imply that low-time pilots need to
shy away from this ship, and that takeoffs and landings are a problem.

I shouild tell you that 128 of my 220 hours in sailplanes are in a
1-35, with another 12 in my PIK-20B. It's as easy to fly as a 1-26, in
my opinion, and we regularly let solo students go in those. My first
flight in the 1-35 came when I had 27 total hours in my log book. I had
mentioned liking the looks of the ship and a desire to fly it. I had
also mentioned my fear of the ship, fostered by comments of some that
had flown it... and those FLAPS... egad!!! Those flaps!!!

Hearing my comments, a fellow TSAer and feminine ASW-20 pilot, told me
there was nothing to fear, that it was just another sailplane. She said
that it had some characteristics that were different from spoilered
ships that had to be respected, that's all. She did me such a great
favor with her comments.

I got an instructor that was familiar with that ship to check me out in
it. He had me memorize the speeds, familiarize myself with the
controls, etc... all pretty normal. Then they had me sit in the
sailplane and lifted the tail to show me the flight attitudes I would
encounter. For my first tow, he had me take off with full negative
flap, and wanted me to take it to thermal position when I had full
aileron control. The tow pilot was instructed not to daudle on initial
acceleration. When I pulled the flaps back to +8, she popped off the
ground and I had a better view of the tow plane than I had ever had
before. Per the instructor, I took a 4K' tow and made 3 mock patterns,
including full flap final approach, with the 4th one to be the first
real landing. I was initially uncomfortable with the nose-down
attitude, but after seeing that those flaps kept the airspeed down, it
became second nature pretty fast. I couldn't believe how well I could
see the airport on final. I was really pleased that by keeping the
airspeed at 60, I could let the flaps off and level the attitude and
clear obstacles... to the other end of the field if necessary.

My first landing in this ship hooked me. I flared by releasing some of
the forward pressure, and at full flap, the airspeed bled away so
quickly that I was amazed. When I heard the first grass touching the
ship I went to full negative flap and touched down on the main and tail
wheel at the same time, at about 35 mph. Where was my fear? Well, it
was where it should have been... gone.

I have heard others bash flapped ships for my whole soaring life. These
comments always seem to come from those that have very limited
experience in these ships, or had bad advise from those that checked
them out in these designs. I recently bought a PIK-20 and it's previous
owner told me a horror story about his first takeoff - with +45 degrees
flap cranked in on advise from an instructor. Was that the fault of the
flaps or the design? I can well imagine the resulting pitch up and
white-knuckled response.

So, my wish is... If you've had a bad experience in such a bird, that
you analyse this experience with someone that regularly flys one.
You'll probably find that you didn't get good instruction, or didn't
follow it. I'm living proof. If I can survive 140 hours in a flapped
ship and not just survive but love it... so can you. They're not
dangerous, just different. Not to be feared, but respected. Let's face
it, if you don't respect a 1-26, it'll kill you.

Stop kicking my old friends... the 1-35s.

Jack Womack

[Bob Whelan]

"Jack" > wrote...

(selectively snipped>
> I've seen several remarks lately in Soaring Magazine and on my home
> club's internet forum about the characteristics of [a 1-35]
> sailplane. Though not directly bashing this ship, comments made seem to
> imply that it's a difficult or dangerous sailplane to fly. I think
> that's wrong.

"Roger that last sentence!"
- - - - - -

> I have heard others bash flapped ships for my whole soaring life. These
> comments always seem to come from those that have very limited
> experience in these ships, or had bad advise from those that checked
> them out in these designs.

Bingo!...
- - - - - -

> I recently bought a PIK-20 and it's previous
> owner told me a horror story about his first takeoff - with +45 degrees
> flap cranked in on advise from an instructor. Was that the fault of the
> flaps or the design?

Indeed...
- - - - - -

> So, my wish is... If you've had a bad experience in such a bird, that
> you analyse this experience with someone that regularly flys one.
> You'll probably find that you didn't get good instruction, or didn't
> follow it. I'm living proof. If I can survive 140 hours in a flapped
> ship and not just survive but love it... so can you. They're not
> dangerous, just different. Not to be feared, but respected. Let's face
> it, if you don't respect a 1-26, it'll kill you.

Well said, spot on, and "Roger your wish and sentiments!"
- - - - - -

> Stop kicking my old friends... the 1-35s.

IMHO inaccurate/misguided opinions seem to travel faster & wider than the
truth, but the good news is the truth seems to have more sticking power in
those determined to seek it out. Congratulations on being able to find &
apply it in this instance!

Regards,
Bob - no-sweat transition from 1-26 to large-deflection-flaps w. 125 hours -
W.

[Wallace Berry]

In article >,
"Bob Whelan" > wrote:

> "Jack" > wrote...
>
> (selectively snipped>
> > I've seen several remarks lately in Soaring Magazine and on my home
> > club's internet forum about the characteristics of [a 1-35]
> > sailplane. Though not directly bashing this ship, comments made seem to
> > imply that it's a difficult or dangerous sailplane to fly.


Yep, the ol' "Flaps of Death" fallacy. Just imagine if the 1-35 were a
V-tail!

I have only flown one glider that uses flaps alone for glidepath
control: an HP-16 (Thanks again Dr. Jim). Clearly, I cheated death as
neither the flaps nor v-tail got me. Absolutely lovely ship and flies a
lot better than my 301 Libelle. Easy to pick a spot and land on it. I'd
be more at ease landing out in the HP-16 than my Libelle.

I think the key is to use enough flap. I've seen too many folks in the
1-35, PIK, or HP's timidly crank in only about half flap and then dive
at the runway. They end up too fast and do the funny looking glide down
the field with their tale way up in the air. Turn final high and crank
them flaps in at least 70 degrees and it's easy from there.

Actually, my favorite system is the trailing edge flap/divebrake combo
used on some of the Glasflugel and Schempp Hirth (and Caproni A-21 if I
rememember correctly). Best of both worlds, but difficult to seal up air
leaks. Not a concern on the older design ships they are found on, but
new ships have laminar flow so far back on the wing that sealing of the
flaps is critical.

I still don't really care for the 1-35 very much, but that is because
better gliders can be had for the same (or less) money.

--
Take out the airplane for reply

[Stewart Kissel]

>IMHO inaccurate/misguided opinions seem to travel faster
>& wider than the
>truth, but the good news is the truth seems to have
>more sticking power in
>those determined to seek it out. Congratulations on
>being able to find &
>apply it in this instance!
>
>Regards,
>Bob - no-sweat transition from 1-26 to large-deflection-flaps
>w. 125 hours -
>W.
>

On the other hand for us cheapskates...this keeps ships
such as the Ventus B affordable! R trailing edge devices
different? U bet. Should they reduce the value of
the ship? Personally I believe the opposite. Having
said that, the Ventus deserves it reputation for less
then sweet handling characteristics.

[Maule Driver]

What sweet memories. As a low time glider pilot, my few flights in a a
1-35 hooked me on flaps. They are a bit different, not necessarily
better, but certainly not dangerous. And the 1-35 is a sweet example.

So my first owned sailplane was a PIK20b. Great ship too. Once one
learned to wind up the flaps while flaring, it could be landed on a
dime. But the path to learning that technique was paved with PIOs
(think rubbing you tummy while patting you head expressed in pitch).

Thanks for the memories...

Jack wrote:

> I shouild tell you that 128 of my 220 hours in sailplanes are in a
> 1-35, with another 12 in my PIK-20B. It's as easy to fly as a 1-26, in
> my opinion, and we regularly let solo students go in those. My first
> flight in the 1-35 came when I had 27 total hours in my log book. I had
> mentioned liking the looks of the ship and a desire to fly it. I had
> also mentioned my fear of the ship, fostered by comments of some that
> had flown it... and those FLAPS... egad!!! Those flaps!!!
>

[Shawn]

Maule Driver wrote:
> What sweet memories. As a low time glider pilot, my few flights in a a
> 1-35 hooked me on flaps. They are a bit different, not necessarily
> better, but certainly not dangerous. And the 1-35 is a sweet example.
>
> So my first owned sailplane was a PIK20b. Great ship too. Once one
> learned to wind up the flaps while flaring, it could be landed on a
> dime. But the path to learning that technique was paved with PIOs
> (think rubbing you tummy while patting you head expressed in pitch).
>
> Thanks for the memories...

You would raise that flaps in the flair? In my Ventus, and now the
Mosquito I fly, that would be really difficult, and the opposite of what
a lot of people do-extending more flap in the flair. I favor the set
'em and forget 'em on short final method. Granted, not quite the same
system.
Do Piks HPs and 1-35 flaps create too much drag to leave out in the flair?

Shawn

[Michael]

Our local DE had a 1-35 on the line, which he mentioned to me when I
mentioned my plans to buy an HP-11. He gave me some advice then, and
in retrospect it was very good advice.

First off, flaps for glideslope control are not an issue. Really no
big deal at all. Sure, a little different, but not difficult.

The issue with my HP-11, and the HP-18 my friend had, and the 1-35 the
local DE had, was weak aileron control on takeoff. On a wide grass
field with a powerful tow plane and all tows into the wind, it's not
much of an issue - you rudder it around until the ailerons come alive,
and then all is well. On a narrow paved runway, with lights on posts
giving the wingtips just a few feet of clearance, a weak tow plane, and
a habit of towing slightly downwind to avoid the inconvenience of
moving, it's a much bigger deal.

Michael

[Derrick Steed]

Do Piks HPs and 1-35 flaps create too much drag to leave out in the
flair?

Shawn

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~

As a PIK 20B driver:

It's not that they create too much drag, it's that it floats for quite a
long way even if your approach isn't fast, and in that float it is
_VERY_ pitch sensitive. The other problem is that once you are down on
the ground there is very little aeleron control and any brake will put
the aircraft on its nose, so it's much easier to complete the initial
part of the flare and then slowly wind in the flap so that the tail
comes down and it settles onto the ground, winding the flaps all the way
to negative allows use of the wheel brake and gives some aeleron
control.=20

Rgds,

Derrick Steed

[Bob Kuykendall]

> Do Piks HPs and 1-35 flaps create too
> much drag to leave out in the flair?

I owned an HP-11 for over a dozen year, and I own an HP-18 now. I love
large-span flaps for glidepath control, and I dearly wish I could
market sailplanes with them. Unfortunately, there are few 2-seaters to
train pilots on them with, and much in the way of rumor and
disinformation about them.

Feed-forward is the key to using large-span flaps for glidepath
control. As you crank in the flaps, you have to simultaneously apply
nose-down pitch. You can refine the pitch input as you go, but you have
to start both the flap and pitch inputs at the same time. If you try to
do it reactively, that is add some flaps and then adjust the pitch when
you detect the airspeed change, you quickly end up way behind the
curve.

In the HP-11, I would often crank on the last bit of flap in the flare
in order to achieve touchdown at the lowest possible energy level. It
takes practice, but once you develop the techniques it becomes easy.

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

[Wayne Paul]

There are several articles relevant to the use of large span flaps on the
"Schreder Sailplane Designs" web site. (http://www.soaridaho.com/Schreder)

See:
http://www.soaridaho.com/Schreder/Stories/Preparing_for_first_HP_flight.htm
http://www.soaridaho.com/Schreder/Large-span_flaps.html
http://www.soaridaho.com/Schreder/Stories/Schreder_on_Flaps.htm

You can get a lot of sailplane for the dollar if you purchase a use
HP/RHJ/RS sailplane.
http://www.soaridaho.com/Schreder/Trading_Post/The_Trading_Post.html

Wayne
HP-14 N990 "6F"
http://www.soaridaho.com/

"Bob Kuykendall" > wrote in message
oups.com...
>
> > Do Piks HPs and 1-35 flaps create too
> > much drag to leave out in the flair?
>
> I owned an HP-11 for over a dozen year, and I own an HP-18 now. I love
> large-span flaps for glidepath control, and I dearly wish I could
> market sailplanes with them. Unfortunately, there are few 2-seaters to
> train pilots on them with, and much in the way of rumor and
> disinformation about them.
>
> Feed-forward is the key to using large-span flaps for glidepath
> control. As you crank in the flaps, you have to simultaneously apply
> nose-down pitch. You can refine the pitch input as you go, but you have
> to start both the flap and pitch inputs at the same time. If you try to
> do it reactively, that is add some flaps and then adjust the pitch when
> you detect the airspeed change, you quickly end up way behind the
> curve.
>
> In the HP-11, I would often crank on the last bit of flap in the flare
> in order to achieve touchdown at the lowest possible energy level. It
> takes practice, but once you develop the techniques it becomes easy.
>
> Bob K.
> http://www.hpaircraft.com
>

[Nick Gilbert]

People wind the flap away upon flair to help make the landing stick (stall
speed goes up, wing stops flying). Obviously, it also gives better aileron
response.

Nick.


"Shawn" <sdotcurry@bresnananotherdotnet> wrote in message
...
> Maule Driver wrote:
>> What sweet memories. As a low time glider pilot, my few flights in a a
>> 1-35 hooked me on flaps. They are a bit different, not necessarily
>> better, but certainly not dangerous. And the 1-35 is a sweet example.
>>
>> So my first owned sailplane was a PIK20b. Great ship too. Once one
>> learned to wind up the flaps while flaring, it could be landed on a dime.
>> But the path to learning that technique was paved with PIOs (think
>> rubbing you tummy while patting you head expressed in pitch).
>>
>> Thanks for the memories...
>
> You would raise that flaps in the flair? In my Ventus, and now the
> Mosquito I fly, that would be really difficult, and the opposite of what a
> lot of people do-extending more flap in the flair. I favor the set 'em
> and forget 'em on short final method. Granted, not quite the same system.
> Do Piks HPs and 1-35 flaps create too much drag to leave out in the flair?
>
> Shawn

[Eric Greenwell]

Nick Gilbert wrote:
> People wind the flap away upon flair to help make the landing stick (stall
> speed goes up, wing stops flying). Obviously, it also gives better aileron
> response.

I agree completely with the effects of raising the flap, but not the
reasons given. What makes the glider "stick" is the reduction in lift
when the flap is raised, not any change in stall speed; in fact, raising
the flap makes the wing less likely to stall because a greater fuselage
angle of attack is now needed to stall. With the glider on the ground,
this angle of attack can't be achieved, as a recent thread made clear.
And this allows the wing to fly longer, enabling the pilot to control it
to a lower speed. (By "fly", I mean produce lift).

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

Eric Greenwell
Washington State
USA

[[email protected]]

Jack wrote:
> If I can survive 140 hours in a flapped
> ship and not just survive but love it... so can you. They're not
> dangerous, just different.

I have had similar good experiences with a flaps-only for
glide-path-control ship. In this case an RS-15. After only 22 hours
of flying anything I took my first flight in the RS. I found the ship
very easy to fly with almost docile handling characteristics,
especially at low speed. Several good things happen when the flaps are
deployed during the landing pattern: 1) stall speed decreases, 2) pitch
stability increases due to the increase in "longitudinal dihedral", 3)
any tendency to tip stall decreases due to the effective increase in
washout. Also, I have never forgotten to connect my spoilers nor have
I ever had spoilers accidently deploy while in flight. I'm not
knocking spoilers, they work just fine. But a flaps-only ship can also
be a real pleasure to fly.

Regards,

-Doug

[Maule Driver]

Derrick Steed wrote:
> Do Piks HPs and 1-35 flaps create too much drag to leave out in the
> flair?
no
> As a PIK 20B driver:
> It's not that they create too much drag, it's that it floats for quite a
> long way even if your approach isn't fast, and in that float it is
> _VERY_ pitch sensitive. The other problem is that once you are down on
> the ground there is very little aeleron control and any brake will put
> the aircraft on its nose, so it's much easier to complete the initial
> part of the flare and then slowly wind in the flap so that the tail
> comes down and it settles onto the ground, winding the flaps all the way
> to negative allows use of the wheel brake and gives some aeleron
> control.=20

I'll second all of that on the PIK20b. First, I think the PIK, 1-35,
and the HP series are all different.

You will float too far in the PIKb using any reasonable speed over the
threshold. Since I learned CC soaring and outlandings in this ship,
precise touchdowns were required. The previous owner, an experienced
racing pilot, taught me the the "wind up the flaps as you flare"
technique after I had 'mastered the float'. I would almost always use
the full 90 deg position on final and wind it to neg 6 deg in the flare
- about 2.5 cranks as I recall. As you cranked, you pulled back and
landed 2 point. Very easy to hit any spot and very easy to do the flare
once you learned to coordinate cranking with one hand while pulling on
the other. You ended up being the afternoon's entertainment in the
meantime. That cranking motion invariably found it's way into your
right hand resulting in pitch PIOs.

If you don't touch the flaps, you would simply sit in ground effect and
wait for the energy to bleed off. Every gust or nudge of the stick
would cause excursions until the wait was over. Coming in on final with
minimum energy was unsafe. A unforseen drop in wind would leave you
without options....

....and that is the main problem with flaps. Once you have them out and
your energy is down, there's little recourse. With spoilers, you can
always slap them closed and return to high performance configuration.

Flaps are great but spoilers are better. Both is best.

[Jack]

I would have to agree with most of the comments made here, including
the one about there being better ships out there for about the same
money. After all, when I put my money down, I didn't buy a 1-35.

I have never had the PIO problem that someone pointed out, but then
with the primary-subject sailplane, the landing flap is just pulled
back as the stick is moved forward.

I never had the float problem, either. I guess I have always used
enough flap and slowed her down to nothing before dumping any of it
off.

The comment about narrow runways with a slight downwind takeoff roll
and a weak towplane... That's asking for trouble in any sailplane, and
perhaps more so in one of tese ships, but I would think an SZD-55
wouldn't be any easier.

One comment that stuck out was the set 'em and forget 'em thoery. I was
taught to modulate these flaps just like spoilers. If the airspeed is
maintained, there's no appreciable loss of altitude in leveling the
nose while removing the flap. I have had 2 instances where I wasn't
seen in the pattern and was VERY glad to be able to back the flaps off
to 0 and extend about 400' and continue my final. This was of course
followed by a debriefing of the offenders about scouring the pattern
for approaching ships. So far, I've had 12 hours in my PIK, interrupted
for the summer by a surgery, but I've had no problems in modulating my
flap input throughout the pattern to maintain proper speeds and
altitudes.

Again, I wasn't knocking spoilers, either, but I do wish those knocking
flaps only ships would really look at the situation or just be quiet...

Jack Womack

[Shawn]

Jack wrote:
> I would have to agree with most of the comments made here, including
> the one about there being better ships out there for about the same
> money. After all, when I put my money down, I didn't buy a 1-35.
>
> I have never had the PIO problem that someone pointed out, but then
> with the primary-subject sailplane, the landing flap is just pulled
> back as the stick is moved forward.
>
> I never had the float problem, either. I guess I have always used
> enough flap and slowed her down to nothing before dumping any of it
> off.
>
> The comment about narrow runways with a slight downwind takeoff roll
> and a weak towplane... That's asking for trouble in any sailplane, and
> perhaps more so in one of tese ships, but I would think an SZD-55
> wouldn't be any easier.
>
> One comment that stuck out was the set 'em and forget 'em thoery.

That was my comment with regard to the trailing edge dive brake/flap
system of the the Ventus and Mosquito. My comment was that once on
*short* final i.e. runway made and on glide for my planned touchdown
point I pull full brakes/flaps and use the stick to control the
remainder of the flight. If the brakes/flaps aren't fully deployed in
the flair, more can be added. I've never found the trailing edge system
to be easily modulated near the ground. My experience has been that if
I try to put them away in the flair I drop onto the runway very inelegantly.

Shawn

[Jack]

>and that is the main problem with flaps. Once you have them out and
your energy is down, there's little recourse. With spoilers, you can
always slap them closed and return to high performance configuration.


Flaps are great but spoilers are better.<

This is the mentality we are talking about. The "spoilers are better"
mentality. What I see wrong with this is the energy shouldn't be blead
off until flair, just like spoilers. The flaps can be dumped if the
airspeed is still there, just like spoilers. The float will be minimal
if the flaps are cranked in as they should be. If you're using 45
degrees... yep... it's gonna float all the way down the runway. The
flaps should be pulled to max during flair if they're not there
already, and should be dumped only at ground contact to facilitate
aileron control for the rest of the landing run - which should be short
if you used the flaps and slowed during flair. Better than spoilers?
Not in my opinion. Spoilers better than flaps? No to that one as well.

Again, I would stress that either one can be used effectively, with the
flaps having a short field advantage for outlandings.

>Both is best. < You'll get no argument from anyone on that one.

Jack Womack

[Maule Driver]

As a former long time PIK owner, I am partial to flaps-only. They are
great, and flexible, and facilitate lower energy landings. Fun like a
tailwheel.

But I've landed in extremely gusty/wind shear conditions on several
occassions. That is, with T-storms over or on the airport (stupid?
Yes.) Flying with spoilers and flaps saved the day. Upon reflection if
given a choice between the 2, it would have to be spoilers. In those
admittedly extreme conditions, airspeed excursions are not entirely in
one's control and spoilers-only are better than flaps-only no matter the
level of pilot proficiency.

I would just add that flap-only techniques appear to be very aircraft
specific. The Pik will float in ground effect all day long with 90
degrees cranked in. If you wait until ground contact to start
retracting them, you will not be able to meet a 10 foot spot standard.
Not applicable to similar types.

Mauledriver, aka Foureyes, aka Bill Watson
....I guess you can figure out why I now fly a Maule - Composite
construction, reflex flaps, no racing class, a tailwheel to enforce
proficiency and an engine to land where the Tstorms aren't....

Jack wrote:
>>and that is the main problem with flaps. Once you have them out and
>
> your energy is down, there's little recourse. With spoilers, you can
> always slap them closed and return to high performance configuration.
>
> Flaps are great but spoilers are better.<
>
> This is the mentality we are talking about. The "spoilers are better"
> mentality. What I see wrong with this is the energy shouldn't be blead
> off until flair, just like spoilers. The flaps can be dumped if the
> airspeed is still there, just like spoilers. The float will be minimal
> if the flaps are cranked in as they should be. If you're using 45
> degrees... yep... it's gonna float all the way down the runway. The
> flaps should be pulled to max during flair if they're not there
> already, and should be dumped only at ground contact to facilitate
> aileron control for the rest of the landing run - which should be short
> if you used the flaps and slowed during flair. Better than spoilers?
> Not in my opinion. Spoilers better than flaps? No to that one as well.
>
> Again, I would stress that either one can be used effectively, with the
> flaps having a short field advantage for outlandings.
>
>
>>Both is best. < You'll get no argument from anyone on that one.
>
>
> Jack Womack
>

[Jim Newton]

I have a 1-35, the one with retract gear and nose skid, and have been
flying it for 9 years but not enough to justify continuing to own it.
So it is for sale. If I thought I'd ever buy another similar glider, I'd
keep this one.
However, I learned from the beginning to operate the flaps and stick in
unison but opposite - pull flaps down, push nose down. It then becomes
second nature. Other than the 30 deg initial flap setting, one can only
lock the flaps in full down position. When landing on grass and have
the the field and landing spot made, I lock the flaps full down and then
have my left hand on the brake for short stops after touch down. One
concern with full flaps is that if your speed is too fast, you touch
down on the nose skid first. So maintaining appropriate speed is of
course essential.
The other thing I like about it is that the aluminum glider is Orange
and not white!
Cheers,
Jim
-----
Remove the T for email..

[Eric Greenwell]

Maule Driver wrote:

> Flaps are great but spoilers are better. Both is best.

That's one of the reasons I prefer Schleicher gliders like the ASW 20,
and now a ASH 26 E.
--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

[Jeffrey Banks]

Hi All,

I have a 1/5 share in a 1-35 here in Alaska. I find
this glider a delight to
fly and the flaps seem to work just fine for approach
control. Once at 30
degrees I can modulate between 30 degs and full without
much trouble just
as I do with spoilers. The nose needs to be pointed
down when adding flaps
and this is quite normal in any aircraft with flaps
that I have flown.
I am amazed at how small an area this glider will land
in. And again how
far it will float at flaps 30. Seems like it has great
spot landing control.

If one is a first timer with flap use there might be
a learning curve that
could best be handled with some dual time in a Cessna
practicing some
power off landings. (I love the older Cessnas with
the manual flaps)

Jeff Banks
N2JY

[Eric Greenwell]

Maule Driver wrote:

> But I've landed in extremely gusty/wind shear conditions on several
> occassions. That is, with T-storms over or on the airport (stupid?
> Yes.) Flying with spoilers and flaps saved the day. Upon reflection if
> given a choice between the 2, it would have to be spoilers. In those
> admittedly extreme conditions, airspeed excursions are not entirely in
> one's control and spoilers-only are better than flaps-only no matter the
> level of pilot proficiency.

A couple HP owners told me that spoilers are preferable to flaps when
flying fast under clouds with strong lift:

* if the lift suddenly increases and threatens to suck you into the
cloud, spoilers can be quickly deployed keep you below the cloud.

* flaps will first increase the lift as you begin to lower them, and
take you into the cloud. Increasing speed to stay out of the cloud may
put you over the speed limit for the flap setting you need avoid the cloud.

Have other HP owners encountered this situation, and how do they cope
with it?

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Eric Greenwell
Washington State
USA

[Maule Driver]

I've never flown an HP. Getting sucked into a cloud seems to primarily
be a strong conditions (e.g. Western US) problem. Happened to me in an
LS6... have no idea what I'd do with a flaps-only ship except exceed
redline. Deploying the spoilers at close to redline scared the stuff
out of me as it was, but it worked.

Eric Greenwell wrote:
>
> A couple HP owners told me that spoilers are preferable to flaps when
> flying fast under clouds with strong lift:
>
> * if the lift suddenly increases and threatens to suck you into the
> cloud, spoilers can be quickly deployed keep you below the cloud.
>
> * flaps will first increase the lift as you begin to lower them, and
> take you into the cloud. Increasing speed to stay out of the cloud may
> put you over the speed limit for the flap setting you need avoid the cloud.
>
> Have other HP owners encountered this situation, and how do they cope
> with it?
>

[Bob Whelan]

"Maule Driver" wrote ...
> I've never flown an HP. Getting sucked into a cloud seems to primarily
> be a strong conditions (e.g. Western US) problem. Happened to me in an
> LS6... have no idea what I'd do with a flaps-only ship except exceed
> redline. Deploying the spoilers at close to redline scared the stuff
> out of me as it was, but it worked.
>
> Eric Greenwell wrote:
> >
> > A couple HP owners told me that spoilers are preferable to flaps when
> > flying fast under clouds with strong lift:
> >
> > * if the lift suddenly increases and threatens to suck you into the
> > cloud, spoilers can be quickly deployed keep you below the cloud.
> >
> > * flaps will first increase the lift as you begin to lower them, and
> > take you into the cloud. Increasing speed to stay out of the cloud may
> > put you over the speed limit for the flap setting you need avoid the
cloud.
> >
> > Have other HP owners encountered this situation, and how do they cope
> > with it?

Having flown an HP-14 for 195 hours and a much-weenier-flapped Zuni for
several thousand, all of it out west, and having in both been concerned
about getting sucked into strong cloud streets, here's what I did:

1) immediately slowed down (to some speed below which full flaps could
easily/safely be put down);
2) put down full flaps;
3) changed course to the nearest cloud edge.
4) gave thanks I was flying a flapped ship!

Low stress, structurally safe. Even if one was so
foolish/bold/situationally-unaware as to go into the cloud immediately upon
the pull-up to slow down, who among us canNOT simply provide a stick input
until the stall, prior to losing control in the cloud? If a pilot can do
that, s/he can put down the flaps after the speed bleeds down. (Individual
mileage may vary. Not approved by the Insurance Institute of America or the
American Bar Association.)

Short of having the magic fairy wave a magic wand, I've a hard time
imagining anything simpler and safer in glider/cloud-avoidance terms. If -
for the sake of limiting this discussion - we ignore *how* one comes to be
in the situation of realizing cloud avoidance is (thought to be) a
necessity, and consider only the (forced) choices of either a) opening
spoilers at high speed for the first time beneath a cloud AND successfully
staying out of said cloud (e.g. Maule Driver!), or b) pulling on full flaps
at low speed AND unsuccessfully NOT staying out of said cloud (not me!), the
coward in me opts for "b)" in a heartbeat. Even with the Zuni's wimpy
large-deflection flaps, there is ZERO risk of exceeding maneuvering speed
and pulling the wings off in a spiral dive, because one must *hold* forward
stick w. full flaps to maintain flying speed.

And, yes, the above was tested and incorporated in a plan long before
needing it in both ships...

Regards,
Bob - gliders can never have too much disposable drag - W.

[Mark Dickson]

At 21:36 19 August 2005, Bob Whelan wrote:
>
>Having flown an HP-14 for 195 hours and a much-weenier-flapped
>Zuni for
>several thousand, all of it out west, and having in
>both been concerned
>about getting sucked into strong cloud streets, here's
>what I did:
>
>1) immediately slowed down (to some speed below which
>full flaps could
>easily/safely be put down);
>2) put down full flaps;
>3) changed course to the nearest cloud edge.
>4) gave thanks I was flying a flapped ship!
>
>Low stress, structurally safe. Even if one was so
>foolish/bold/situationally-unaware as to go into the
>cloud immediately upon
>the pull-up to slow down, who among us canNOT simply
>provide a stick input
>until the stall, prior to losing control in the cloud?
> If a pilot can do
>that, s/he can put down the flaps after the speed bleeds
>down. (Individual
>mileage may vary. Not approved by the Insurance Institute
>of America or the
>American Bar Association.)
>

>
>
>
It would be a lot easier with airbrakes - just open
them.

[Udo Rumpf]

I have not encountered a situation where this would be an issue near the
clouds. I would just speed up.
I would not mind having spoilers on occasions, when it is necessary to
insert one self into a pattern after many gliders return at the same time in
a contest setting. Even then when I am finally committed to land after I
have given way because I was not able to quickly get into on opening. The
landings are most civilized even
if some one is worse off then I in terms of squeezing in there is always
enough space for gliders to land. One does not always have to land near the
trailer.
Regards
Udo

[Bill Daniels]

"Udo Rumpf" > wrote in message
...
> I have not encountered a situation where this would be an issue near the
> clouds. I would just speed up.
> I would not mind having spoilers on occasions, when it is necessary to
> insert one self into a pattern after many gliders return at the same time
in
> a contest setting. Even then when I am finally committed to land after I
> have given way because I was not able to quickly get into on opening. The
> landings are most civilized even
> if some one is worse off then I in terms of squeezing in there is always
> enough space for gliders to land. One does not always have to land near
the
> trailer.
> Regards
> Udo
>
This whole thread says a lot about glider flight training. Airplane pilots
are trained with flaps so they are comfortable with them. Glider pilots are
trained with spoilers, since there are no flapped trainers, so that's what
they are mostly comfortable with.

In fact, a skilled pilot can handle any situation with either.

If there's a situation where a pilot feels uncomfortable, talking with an
instructor skilled in flapped gliders is advisable. (ASK first whether the
instructor has any time in a flap-only glider.)

I have flown both and, although most of my experience is in spoiler equipped
gliders, I prefer flaps for all the reasons the pro-flap folks have listed.
I'll add another. Spoilers, even when closed, disrupt the upper wing
surface in the most critical area - flap only wings are cleaner.

Bill Daniels

[Eric Greenwell]

Bill Daniels wrote:
> Spoilers, even when closed, disrupt the upper wing
> surface in the most critical area - flap only wings are cleaner.

And yet, on a well built glider, you can carefully smooth and seal the
spoilers so there is no leakage or surface unevenness, test the glider,
and it isn't any better. My recollection from Johnson's tests is the
most critical area on the wing is the first few inches of the nose (bug
problems), and that the boundary layer is thick enough at the spoilers
that they do not affect the flow on the typical racing glider.

One might also consider how much "disruption" in air flow a Holighaus or
Waibel would tolerate! Even if I'm right about the airflow disruption,
it doesn't negate the principal advantages of flaps, but I think most
pilots would prefer a combination of the two.

There may also be performance issues related to designing a modern flap
only glider: because modern airfoils use such narrow control surfaces, a
flap only glider might not have enough glide path control. I was
astonished at the difference in glide angle between my ASW 20 and my ASH
26 E, even though they employ the same flap system for landing: the ASW
20 descended much more steeply than does my ASH 26. Even though part of
that is likely due to the higher wing loading on the 26, the flap chord
on the 20 is almost double that on the 26.

--
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Eric Greenwell
Washington State
USA

[Udo]

Eric Greenwell wrote:
> Bill Daniels wrote:
> > Spoilers, even when closed, disrupt the upper wing
> > surface in the most critical area - flap only wings are cleaner.
>
> And yet, on a well built glider, you can carefully smooth and seal the
> spoilers so there is no leakage or surface unevenness, test the glider,
> and it isn't any better. My recollection from Johnson's tests is the
> most critical area on the wing is the first few inches of the nose (bug
> problems), and that the boundary layer is thick enough at the spoilers
> that they do not affect the flow on the typical racing glider.
>
> One might also consider how much "disruption" in air flow a Holighaus or
> Waibel would tolerate! Even if I'm right about the airflow disruption,
> it doesn't negate the principal advantages of flaps, but I think most
> pilots would prefer a combination of the two.
>
> There may also be performance issues related to designing a modern flap
> only glider: because modern airfoils use such narrow control surfaces, a
> flap only glider might not have enough glide path control. I was
> astonished at the difference in glide angle between my ASW 20 and my ASH
> 26 E, even though they employ the same flap system for landing: the ASW
> 20 descended much more steeply than does my ASH 26. Even though part of
> that is likely due to the higher wing loading on the 26, the flap chord
> on the 20 is almost double that on the 26.
>
> --
> Change "netto" to "net" to email me directly
>
> Eric Greenwell
> Washington State
> USA

True,
I am building a new wing and I was hoping to include landing flaps
only.
The airfoil was not given me the results I desired with the larger
flaps. I had to reduce the flap size to 16% and install spoilers. The
flap/aileron arrangement will similar to the DG800,
May real preference would be the ASW20/26/27 set-up but I decided to
keep it simple
As for surface aerodynamics the spoilers are always past the laminar
transition. Smooth and sealed spoiler boxes have no ill effect.
In my case the max transition on the top surface will be at 66% and
that is where the box will be installed.
Regards
Udo

[Ray Lovinggood]

One question for 'flaps only' glider drivers:

On a cross country aero tow, do you ever feel a need
for some type of draggy things to help keep you in
tow position?

If you need a tow speed fast enough to get you home
before the sun sets but that makes it too fast to deploy
flaps, what procedure do you use, if and when necessary,
to keep the towrope tight? Yea, yea, yea, I know:
Fly it properly and you won't need to worry. But
what about when the tuggie snoozes a little and starts
a slight descent and gains speed. (Hey, I'm not even
sure spoilers could help out here.)

Popping spoilers out sure works nicely and easily.

And by the way, I don't like cross-country aerotows.
Sometimes, I think I would rather have the trailer
instead of the towplane.

Ray Lovinggood
Carrboro, North Carolina, USA
LS1-d (No flaps. Spoilers only)

[Eric Greenwell]

Udo wrote:

> Eric Greenwell wrote:
>>There may also be performance issues related to designing a modern flap
>>only glider: because modern airfoils use such narrow control surfaces, a
>>flap only glider might not have enough glide path control. I was
>>astonished at the difference in glide angle between my ASW 20 and my ASH
>>26 E, even though they employ the same flap system for landing: the ASW
>>20 descended much more steeply than does my ASH 26. Even though part of
>>that is likely due to the higher wing loading on the 26, the flap chord
>>on the 20 is almost double that on the 26.

>
> True,
> I am building a new wing and I was hoping to include landing flaps
> only.
> The airfoil was not given me the results I desired with the larger
> flaps. I had to reduce the flap size to 16% and install spoilers. The
> flap/aileron arrangement will similar to the DG800,
> May real preference would be the ASW20/26/27 set-up but I decided to
> keep it simple
> As for surface aerodynamics the spoilers are always past the laminar
> transition. Smooth and sealed spoiler boxes have no ill effect.
> In my case the max transition on the top surface will be at 66% and
> that is where the box will be installed.

Interesting! On my ASH 26 E, the flap chord is 15.5% at the root (root
chord 33 inches), and the leading edge of the spoiler cap is at 48%.


--
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Eric Greenwell
Washington State
USA

[Udo]

The pressure recovery on the ASW26/27 is a bit more conservative. As
far as I know the transition for your wings if it uses the same
airfoil as the ASW27, would be about 59% in cruise and in climb about
65%. Top surface only.
As I had very good experience with my previous project regarding
pressure recovery and not wanting to use forced transition past the
hinge line on the bottom surface I came up with an airfoil that would
meet my requirement on paper and I think it is a good compromise.
The up-shot is the total wetted laminar flow around the airfoil is
about the same as the ASW27. In cruise it should be at par and in climb
it will have a small advantage and for that I will have to wait a wile
yet,
to see if I am right.
Regards
Udo

[Doug Hoffman]

Ray Lovinggood wrote:
> One question for 'flaps only' glider drivers:
>
> On a cross country aero tow, do you ever feel a need
> for some type of draggy things to help keep you in
> tow position?
>
> If you need a tow speed fast enough to get you home
> before the sun sets but that makes it too fast to deploy
> flaps, what procedure do you use, if and when necessary,
> to keep the towrope tight?

"Too fast to deploy flaps" might be an overly-simplified statement of
the situation. How fast are we talking and how much flap are we
deploying? It doesn't take much flap to create significant drag. In
other words, it is likely OK to deploy a little bit of flap at high
speeds. Or perhaps just return them to neutral if you had them
reflexed.


Another nice "trick" is the ability to make the towplane more visible.
Cranking in a little flap such that the glider assumes a slightly nose
down attitude works nicely and easily.

Regards,

-Doug

[Glen Kelley]

Unfortunately, I just had the opportunity for an aero retrieve in my PIK-20.
8 deg. positive flap made for a comfortable tow at 70 - 75 knots and held
good tension during the occasional "snooze".


"Doug Hoffman" > wrote in message
ups.com...
>
> Ray Lovinggood wrote:
>> One question for 'flaps only' glider drivers:
>>
>> On a cross country aero tow, do you ever feel a need
>> for some type of draggy things to help keep you in
>> tow position?
>>
>> If you need a tow speed fast enough to get you home
>> before the sun sets but that makes it too fast to deploy
>> flaps, what procedure do you use, if and when necessary,
>> to keep the towrope tight?
>
> "Too fast to deploy flaps" might be an overly-simplified statement of
> the situation. How fast are we talking and how much flap are we
> deploying? It doesn't take much flap to create significant drag. In
> other words, it is likely OK to deploy a little bit of flap at high
> speeds. Or perhaps just return them to neutral if you had them
> reflexed.
>
>
> Another nice "trick" is the ability to make the towplane more visible.
> Cranking in a little flap such that the glider assumes a slightly nose
> down attitude works nicely and easily.
>
> Regards,
>
> -Doug
>

[Maule Driver]

That seems like a workable plan and well thought out.

But, the 6 allowed spoiler deployment up to redline as I recall so
pulling the spoilers was a perfectly legit operation and resulted in
immediate slowing and increased descent rate. Having the spoilers
sucked out and whistling at close to redline did get my attention along
with the hail coming at me from below.

The best solution is 'terminal velocity' spoilers that once deployed,
prevent acceleration to redline. 1-34 had 'em I think. Nice but not
required.

Flaps are workable, spoilers still seem just a bit better to this pilot.

Bob Whelan wrote:
> "Maule Driver" wrote ...
>
>>I've never flown an HP. Getting sucked into a cloud seems to primarily
>>be a strong conditions (e.g. Western US) problem. Happened to me in an
>>LS6... have no idea what I'd do with a flaps-only ship except exceed
>>redline. Deploying the spoilers at close to redline scared the stuff
>>out of me as it was, but it worked.
>>

> Short of having the magic fairy wave a magic wand, I've a hard time
> imagining anything simpler and safer in glider/cloud-avoidance terms. If -
> for the sake of limiting this discussion - we ignore *how* one comes to be
> in the situation of realizing cloud avoidance is (thought to be) a
> necessity, and consider only the (forced) choices of either a) opening
> spoilers at high speed for the first time beneath a cloud AND successfully
> staying out of said cloud (e.g. Maule Driver!), or b) pulling on full flaps
> at low speed AND unsuccessfully NOT staying out of said cloud (not me!), the
> coward in me opts for "b)" in a heartbeat. Even with the Zuni's wimpy
> large-deflection flaps, there is ZERO risk of exceeding maneuvering speed
> and pulling the wings off in a spiral dive, because one must *hold* forward
> stick w. full flaps to maintain flying speed.
>

[Maule Driver]

I've done it in the PIK. Like everything else, a little flap specific
technique makes it work ok. Spoilers are a bit easier (mindless).

The fun is in reflexing them and pulling into side by side formation
with the towplane... :-)

Ray number ?
Bill in Durham

Ray Lovinggood wrote:
> One question for 'flaps only' glider drivers:
>
> On a cross country aero tow, do you ever feel a need
> for some type of draggy things to help keep you in
> tow position?
>
> If you need a tow speed fast enough to get you home
> before the sun sets but that makes it too fast to deploy
> flaps, what procedure do you use, if and when necessary,
> to keep the towrope tight? Yea, yea, yea, I know:
> Fly it properly and you won't need to worry. But
> what about when the tuggie snoozes a little and starts
> a slight descent and gains speed. (Hey, I'm not even
> sure spoilers could help out here.)
>
> Popping spoilers out sure works nicely and easily.
>
> And by the way, I don't like cross-country aerotows.
> Sometimes, I think I would rather have the trailer
> instead of the towplane.
>
> Ray Lovinggood
> Carrboro, North Carolina, USA
> LS1-d (No flaps. Spoilers only)
>
>
>

[Maule Driver]

Didn't your stick arm get tired holding the nose down? Mine did as I
recall because you couldn't trim it out. 70 - 75 knots would be nice
but seems like most tow planes in cruise want to go a bit faster.

Glen Kelley wrote:
> Unfortunately, I just had the opportunity for an aero retrieve in my PIK-20.
> 8 deg. positive flap made for a comfortable tow at 70 - 75 knots and held
> good tension during the occasional "snooze".
>

[Ray Lovinggood]

To Bill in Durham:

Bill, I'm still Ray #4.

But when it comes to any kind of racing, I'm Ray #last.

Ray Lovinggood
Carrboro, North Carolina, USA

At 16:24 20 August 2005, Maule Driver wrote:
>I've done it in the PIK. Like everything else, a little
>flap specific
>technique makes it work ok. Spoilers are a bit easier
>(mindless).
>
>The fun is in reflexing them and pulling into side
>by side formation
>with the towplane... :-)
>
>Ray number ?
>Bill in Durham

[For Example John Smith]

The Glasflugel Mosquito flap/spoiler combo is terminal speed limiting. I
believe that was a requirement until right around 1980?
I've fully deployed the flaps+spoiler on mine and pointed the nose something
near vertical and didn't exceed manuvering speed. The POH says they can be
fully & abruptly deployed at up to redline, but be ready for the 2G
deceleration shock.


"Maule Driver" > wrote in message
om...
>
> The best solution is 'terminal velocity' spoilers that once deployed,
> prevent acceleration to redline. 1-34 had 'em I think. Nice but not
> required.
>

[Eric Greenwell]

For Example John Smith wrote:

> The Glasflugel Mosquito flap/spoiler combo is terminal speed limiting. I
> believe that was a requirement until right around 1980?

It disappeared in the mid or late 60's, which is why the Std Cirrus and
other late 60's - early 70's gliders had relatively weak spoilers.

My ka-6E had terminal speed limiting spoilers, and I enjoyed their
ability.

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Eric Greenwell
Washington State
USA