Wingdrop while stalling

Wright1902Glider wrote:

When tested at high AOA's, massive tip stalls caused the wing to roll 45
degrees and yaw 180 degrees about every 3 seconds.

Was this a model or was it piloted?

Dave 'bowling balls' Hyde

Dave Hyde wrote:
Wright1902Glider wrote:


When tested at high AOA's, massive tip stalls caused the wing to roll 45
degrees and yaw 180 degrees about every 3 seconds.


Was this a model or was it piloted?

Dave 'bowling balls' Hyde

Yea, that'd be heck in a dog fight. You could fly a tight landing
pattern, though.

Nafod "nafod" 40

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?

One character who worked on this kite several years ago said that the
stall actually started mid-wing, and progressed very quickly, so that
one wing (entire wing, not just the tip or root) stalled and dropped.
Dunno if he was farting or not.

Has anybody used the protruding rivet approach before to solve wing
aerodynamic problems before? Quite a minimalist solution!

Drake Lars

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.

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!

Separation bubbles?


OT: BTW, my experimental glider was a full-sized HG, and I tested it both
clipped-in and unclipped. The second method was preferable, as the first
allowed the glider to drag me all over the beach at Kitty Hawk. I should note
that when I designed this machine, I had very little understanding of the fine
points of non-rigid delta-wing aerodynamics. There's a photo of it on my
website. Its the "Stormy Petrel 3" photo. The "Stormy Petrel 2A" was a
modified "Batso" glider and flew fairly well.

Harry
http://hometown.aol.com/wright1902/page3.html

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.

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.