Round,Circle & Annular Wing Aircraft ?

[hesham]

Hi,


I found a good site about round wing aircraft,most of its aircraft are real and a little
fake airplanes,I found a annular-wing aircraft for designer called, Robert D. Andrews,
and I don't know if it was a real plane or not?,who can help.


http://celticowboy.com/Round Aircraft Designs.htm

 

[hesham]

From Aeroplane monthly 1976.

 

[riggerrob]

Over on www.homebuiltairplanes.com we have enjoyed lengthy discussions about annular, Arup, circular, delta, Piana Canova, Vought, etc. low aspect-ratio (less than 3:1) wing planforms.
The lighter versions fly well because of their low wing loadings.
OTOH planform makes a huge difference at higher angles of attack. With power any less than supersonic fighters, operating at steep angles of attack is impractical. Yes, sharply swept leading edges can generate massive votices at high angles of attack, but they also generate massive amounts of drag. One rumor has it that Concordes. low aspect-ratio ogee delta generated such massive amounts of drag at low airspeeds - and high angles of attack - that it was possible to fly a Concorde into a corner that it could not "power" out of. The only other option was sacrificing massive amounts of altitude to regain airspeed.
When developing his Facetmobile, engineer Barnaby Wainfain found that the secret is making aspect-ratio so small that wing tip vortices collide on the center-line, cancelling each other out. Vertical fin design also makes a huge difference with center-line or wing tip mounted fins working well, but mid-span fins just confusing the vortices.
One boffin did a series of wind tunnel test with a variety of LAR models and concluded that the most efficient was a reverse Arup or delta that pushed WTV as far outboard and as far aft as possible.

 

[Cy-27]

Further to Hesham's note #2, attached is a photo model of the Lee-Richards Annular Monoplane on display at the Science Museum, London. Also attached are a couple of shots of the replica Lee-Richards Annular Biplane design at the museum at Newark, Nottinghamshire.

 

[publiusr]

Hi,


I found a good site about round wing aircraft


http://celticowboy.com/Round Aircraft Designs.htm

Now that is a rug site…

 

[hesham]

Hi,

http://www.oldmagazinearticles.com/round-wing-aircraft-pdf

 

[publiusr]

Wingwalker promenade…

 

[hesham]

From Aeroplane 1948.

 

[riggerrob]

Further to Hesham's note #2, attached is a photo model of the Lee-Richards Annular Monoplane on display at the Science Museum, London. Also attached are a couple of shots of the replica Lee-Richards Annular Biplane design at the museum at Newark, Nottinghamshire.

I suspect that the Lee-Richards biplane was primarily a structural solution to the low-powered engines of its day. biplanes are essentially deep box-beams and can be built much lighter than monoplanes. Low weight being important when you only have a few horsepower. At those low airspeeds all the drag created by all those struts and wires is insignificant. Remember that drag increases with the square of the airspeed.

I predict that the next radical biplane racer (think Reno Air Races) will have toroidal wings with a Schumann planform top wing blending into a reverse-tapered bottom wing. Top wing will get inverse, elliptical, anhedral (aka. drooped tips) while the bottom wing rise to meet it with a similar elliptical, upwards dihedral. Schumann planform has major sweep in its elliptical leading edge combined with a bit of sweep in the trailing edge to minimize pressure differential at the wing tips. The bottom wing will have elliptical, forward swept leading edges with even greater, elliptical forward sweep along its trailing edges. IOW Schumann planform pushes wing tip vortices as far outboard as possible and makes them as small as possible.
This complex, curved-in-all-dimensions planform can only be drawn with CAD and only manufactured in female molds built to tight tolerances.
Combine this with
See toroidal marine propellers for the inspiration.

 

[hesham]

From Aeroplane 1948.

The second whole article.