Wingdrop while stalling

Wright1902Glider wrote:

OT: BTW, my experimental glider was a full-sized HG, and I tested it both
clipped-in and unclipped.

You are a brave, brave man. :-)

Dave 'pirouette' Hyde

On Thu, 15 Jan 2004 17:01:06 GMT, Richard Lamb
wrote:

drake wrote:

Hi all,

Thanks for your replies.

The a/c in question is:
http://www.bharat-rakshak.com/IAF/Im...nt/Deepak.html

The wingdrop problem has been solved (some years back). Just learnt
that all the engineers did was to replace the counter-sunk flat top
rivets on the wing-top (holding the skin to the ribs) were replaced by
protruding pan-head rivets, which apparently energised the flow (made
it more turbulent?). There were rivets all over the wing, but more
towards the wing-root side. This solved the wing drop problem i.e. the
wing drop while stalling was then gentle enough to be handled by
novice pilots. I still am not completely satisfied with the turbulence
explaination... why should a more "energised" flow make the wing drop
less violent?

Sounds like the round head rivets are acting like turbulators.

They have done this in Bonanzas for years.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

If the boundry layer is not attached to the surface, none of the
"energy" in the flow is transfered to the surface.

Basically, tickling the boundry layer like that causes it to reattach
to the surface. That's what they mean by "energizing" the flow.

Make more sense?

Richard (the new improved)Lamb

Hi ya'll!

It must be poor wing design if you have to modify the airfoil with a flow
disrupting rivet head.

My Bellanca doesn't have a wing drop problem and doesn't have any rivet
heads either.

Wonder what the Glass plane builders are doing?
Designing the wing correctly?
--
Cy Galley - Bellanca Champion Club
Newsletter Editor-in-Chief & EAA TC
www.bellanca-championclub.com
Actively supporting Aeroncas every day
Quarterly newsletters on time
Reasonable document reprints

"Roger Halstead" wrote in message
...
On Thu, 15 Jan 2004 17:01:06 GMT, Richard Lamb
wrote:

drake wrote:

Hi all,

Thanks for your replies.

The a/c in question is:
http://www.bharat-rakshak.com/IAF/Im...nt/Deepak.html

The wingdrop problem has been solved (some years back). Just learnt
that all the engineers did was to replace the counter-sunk flat top
rivets on the wing-top (holding the skin to the ribs) were replaced by
protruding pan-head rivets, which apparently energised the flow (made
it more turbulent?). There were rivets all over the wing, but more
towards the wing-root side. This solved the wing drop problem i.e. the
wing drop while stalling was then gentle enough to be handled by
novice pilots. I still am not completely satisfied with the turbulence
explaination... why should a more "energised" flow make the wing drop
less violent?

Sounds like the round head rivets are acting like turbulators.

They have done this in Bonanzas for years.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

If the boundry layer is not attached to the surface, none of the
"energy" in the flow is transfered to the surface.

Basically, tickling the boundry layer like that causes it to reattach
to the surface. That's what they mean by "energizing" the flow.

Make more sense?

Richard (the new improved)Lamb

Hi ya'll!

"Cy Galley" wrote in message
news:69SNb.79462$I06.340710@attbi_s01...
It must be poor wing design if you have to modify the airfoil with a flow
disrupting rivet head.

Are you kidding?

Airfoil selection and wing design is about making priorities and
compromises.

The majority of planes have some external flow control and I wouldn't
consider every one a case of poor wing design.

Dave,

I could send ya a few photos of Chuck S. flying the same kinda gliders back in
the 70's. I may be a nut, but I'm not the only nut. ;-)

By the way, my Wright 1902 is also airworthy. I haven't tried flying it yet
though. It'll be a while before I have the financial and logistical resources
(and spare parts) to mount an expedition to Kitty Hawk with it.

Harry

Deja vu all over again - wasn't there a 90-post thread on this topic
(need for thingies sticking up != bad wing design) a couple months
back? Save your fingers and check the archives....

The Deepak is a nifty-looking little trainer, though. Side-by-side
seating, right?

"C.D.Damron" wrote in message news:s0WNb.81800$na.43654@attbi_s04...
"Cy Galley" wrote in message
news:69SNb.79462$I06.340710@attbi_s01...
It must be poor wing design if you have to modify the airfoil with a flow
disrupting rivet head.

Are you kidding?

Airfoil selection and wing design is about making priorities and
compromises.

The majority of planes have some external flow control and I wouldn't
consider every one a case of poor wing design.

Cy Galley wrote:

It must be poor wing design if you have to modify the airfoil with a flow
disrupting rivet head.

Do you consider any airplane with vortex generators,
washout, or stall strips a poor design? Round-head rivets
sound like a pretty slick and cheap way of adding
vortex generators to me. The list of 'poor designs'
(your words, not mine) that have flow-disrupting
devices to address stall characteristics is long and
distinguished.

My Bellanca doesn't have a wing drop problem and
doesn't have any rivet heads either.

Give any decent aero guy ten minutes with your Bellanca
and he/she could come up with some ugly external mod that
could improve performance in some part of the envelope.
Doesn't mean it's a poor design - nor does adding an
aerodynamic 'band-aid' rather than redesigning an
entire wing when flight test doesn't match predictions.

Wonder what the Glass plane builders are doing?
Designing the wing correctly?

Or maybe just accepting the compromises that were designed
in from the start? Should a designer faced with a 'wing drop
problem' scrap the entire wing design altogether and start from
scratch when a simple fix will suffice?

Dave 'trade study' Hyde

On Fri, 16 Jan 2004 14:01:38 GMT, "Cy Galley"
wrote:

It must be poor wing design if you have to modify the airfoil with a flow
disrupting rivet head.

My Bellanca doesn't have a wing drop problem and doesn't have any rivet
heads either.

I don't think the early Debs had any washout either.

Sure it drops a wing if you aren't on it, or aren't too sharp
yourself, but with a bit of practice using rudder only you can hold
it in a stall with the nose way up there while wobbling around. Just
don't try to center the ball while doing that. It'll roll over every
time.

I'm so used to it I never figured dropping a wing a bit was anything
to worry about. A little rudder stops it right away. OTOH a lot of
rudder can make for an exciting day:-))

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
Wonder what the Glass plane builders are doing?
Designing the wing correctly?

(Corrie) wrote in message . com...
Deja vu all over again - wasn't there a 90-post thread on this topic
(need for thingies sticking up != bad wing design) a couple months
back? Save your fingers and check the archives....

The Deepak is a nifty-looking little trainer, though. Side-by-side
seating, right?

Yes side-by-side seating. The canopy looks cool! (More on the Deepak
below, but is skippable)
Never flew in it though (Infact, flew for the 1st time (ever) in a
Saratoga(sedate plane, though several people did get airsick) and then
in a Supercub (what a sexy old bird!) about 20 days back.(Hey, is
there a '1st time in the air' thread?? )


Is there any refernce to Bonanzas using pan-head rivets at turbulators
anywhere?

And why would a more turbulent airflow prevent tip stalling?(leading
to wing drop) Wont it mean that the tip will stall at a higher AoA? Or
the fact that there were more such rivets towards the root side have a
stablizing effect while stalling?

Boring stuff on the HAL HPT-32 DeepakU may skip)
Specs:http://www.bharat-rakshak.com/IAF/Ai...cs/Deepak.html
Pics:http://www.bharat-rakshak.com/IAF/Im...nt/Deepak.html
http://www.airshowreport.com/india/008.htm

The Indian fedral audit doomsayers report on the plane and the
problems it had:
(Says the Textron Lycoming engine is causing too much pain)
http://www.cagindia.org/reports/defe...1/chapter3.htm
Goto "7.6.2 Unreliability of trainer aircraft 7.6.2.1 HPT-32 aircraft"


The Indian Parliamentary committee invetigates above report:
(The problem is not the engine but...)
http://164.100.24.208/ls/committeeR/...th/report.html
Goto "5.2.1 HPT-32 aircraft"

Apparently, all problems solved now, the Indian Air Force has ordered
even more Deepaks.

Blue skies y'all,
Lars

ObAeroJoke(from http://iron-eagles.tripod.com/jokes.html):
ATC: "HPT-32, what are your intentions?"

HPT 32: "To get my wings and become a fighter pilot sir."

ATC: "I meant in the next 5 minutes, not ten years!"