All Moving Wings

[paulo]

OK, so on a high end aerobatic aircraft, flaps are dispensed with to enable full length aelierons, and you start getting 300+ degree/sec roll rates.

Hypethetically the next step could be all moving wings, in the same vane as the all moving tail plane, but opposed, to achieve truly stupendous roll rates.

I'm wondering whether anyone has ever tried this (arguably stupid) idea?

[Intruder]

NASA is working with an F-18 with wing warping.

[paulo]

Thanks intruder - I've done a bit more reading and discovered that the idea goes back some way. All the way to the beginning in fact, with the Wright Flyer.

[Winkiepinkie]

And the French geezer who crossed the channel the first time (Bleroit). Pretty sure his was an all moving wing...

[Onan the Clumsy]

I saw the title and thought you meant flapping, like an ornithopter. There was an article in this month's ... AOPA Pilot (?) about someone who was using trained parrots to study the phenomenan (seriously). They had a picture of this parrot with what looked like a 1950s era spacesuit helmet on. Very strange loking but the bird didn't seem to mind. I think he's really looking to mimic the effect in an aircraft.

[cwatters]

> I'm wondering whether anyone has ever tried this

It's been tried on model aircraft several times over the years. The main problem is a lack of torsional (twisting) strength... it's quite possible to have a whole wing flutter and shed itself at speed.

> And the French geezer who crossed the channel the first time
> (Bleroit). Pretty sure his was an all moving wing...

Not quite. He had wing warping. The wing root was fixed in relation to the tailplane.

[Keith.Williams.]

Almost every helicopter ever built has used all moving (feathering) wings on both the main and tail rotors.

[paulo]

Yeah Keith, but that's just a VP prop that's been incorrectly mounted ;)

cwatters - any idea whether these experiments were using a single axial mounting point (which is going to have huge torsional issues), or something where there is - say - a leading pivot point, and a trailing lever arm?

[Genghis the Engineer]

There's a French Biplane called an Aviasud Mistral with an all moving lower wing. Drops a wing horribly at the stall because it's hard to ensure that they are properly parallel, and the roll feel is funny - the UK put anti-balance tabs on the inboard trailing edge which helped a bit.

But, I'm not sure it'll ever replace the Aileron. Nor, frankly do I see the need - snappy roll response is in large part produced by low to neutral lateral stability combined with low roll damping, then adequate aileron power.

G

http://ethics.tamu.edu/guest/MistralAircraft_files/image001.jpg

[paulo]

Cheers Genghis.

Just a hypothetical discussion for the 'Scruggs Industries Carbon Wunderstunta' *


* (C) Alan Cassidy. ;)

[stillalbatross]

Nasa and General Dynamics did it with an F111 about 15 or 20 years ago. Called it the DWC (deformable wing concept). Have a look at Janes from a few years back

[RatherBeFlying]

As I recall the Toronado has tailerons and likely a number of other mil types do as well.

Same idea, just different fuselage station;)

[Genghis the Engineer]

Had that on the couple of Jaguars on the ETPS fleet, it was called diff-tailplane.

I've no idea how effective it was, it never stayed serviceable long enough to find out.

G

[SSC]

Goes back beyond the Wright Brothers: Leonardo Da Vinci proposed it back when the world was still flat and the universe orbited around Rome.

BBC had a program on it earlier this year: as I recall a couple of aircraft engineers built it and a husband and wife hangliding team got to fly it. (well, being the lighter of the two she flew it and he looked very, very nervous). :\

[regbench]

Model aircraft today - full size tomorrow?

A company in the US produces a radio-controlled model ornithopter - span about 4 feet - which is powered by an electric motor and flies for about 10 minutes on a single charge of its rechargeable battery. Not beyond the bounds of possibility to scale it up - but what type of licence would you need to fly it? :ouch:

[cwatters]

> cwatters - any idea whether these experiments were using a
> single axial mounting point (which is going to have huge
> torsional issues), or something where there is - say - a leading
> pivot point, and a trailing lever arm?

I first saw all moving wings in the 1970's. At the time normal model gliders typically featured a two piece foam/veneer wing to make transport easy. The wings were joined together using a tube 'joiner' roughly located on the CoG. When a round tube was used a smaller joiner (usually wire) was used to stop the wing rotating about the main tube...

So take the rear joiner out and you have all moving wings. I recall seeing two models - one had a conventional elevator and just used the all moving wing for roll control, and another that had a fixed tail. The latter used two servos one on each wing panel so that the wings could be moved together for pitch control and seperatly in oposition for roll control.

There was even a kit was produced in the early 80's - but I recall seeing two break up in the air at speed. These days carbon rods and tubes are available which would make things easier.

[Agaricus bisporus]

Believe all moving wing was used on the US Navy's F8 Crusader as a means of raising angle of attack at slow speeds, also used on the Helio Courier liason/spotter aircraft of the Viet-Nam era. There has been a regular French visitor to the PFA rally in recent years with a homebuilt staggered unbraced biplane that uses a lower forward fixed wing and the aft top wing with variable incidence for pitch(?) control. It evidently works OK. I believe this was a development of the infamous Pou de Ciel that killed so many people in the'30s that it was banned... Tilt rotors of various kinds have tilted wings in the past, but as some sage noted above it only seems to be helicopters that have actually developed the differential pitch wings mentioned in the original post. Helos win again, I reckon!

[Genghis the Engineer]

The French thing you're talking about is the known as the Mignet system.

A staggered biplane with lots of dihedral. The rear (lower) wing is fixed, the forward (upper) wing is all moving in pitch and is the pitch control. The tail has no horizontal stabiliser, but the rudder is driven by the cockpit roll control. There's no primary roll control, roll is through secondary effect of rudder.

I've flown two variants. The HM1000, which is approved in the UK as the "Balerit" is a 2-seater. Slow, sluggish, Dutch rolls all over the place - but essentially easy to fly and utterly viceless. In aid of my profession I spent several hours trying to spin one once and failed dismally. Very effective folding wings...
http://www.hmshtf.org/collection/images/hm1000forget.jpg


The other, the HM293 is a single seat taildragger, feels to fly like I imagine a WW1 fighter would. I timed 1.8 seconds from 60° (steady) to 60° (steady) - incredibly crisp and responsive in roll. Pretty reasonable in pitch. Still Dutch rolls all over the place, and I didn't get enough flying in it to come to terms with landing a taildragger where the rudder is driven through the stick. Thoroughly good fun however, I strongly recommend it if you ever get a go in one.
http://www.pilotlist.org/tagazous/images/80hg.jpg



The original Mignet Flying Flea (Pou du Ciel) was the HM14, which killed people by virtue mainly of a very unforgiving wing section. The modern ones in France usually use the HM293's wing section which lacks the original (and severely inadvisable) sharp leading edge.
http://www.valkyrie.net/~flyingflea/hmlge.gif

G