Lockheed Ring-Wing Projects

[hesham]

Hi,


in article about Lockheed projects in Luftfahrt 2/1983,there is a section about ring wing aircraft,they displayed some Lockheed Models and aircraft,I am not sure of all of those 5 drawings to Lockheed or not,some help please.

 

[Stargazer]

Too small! Can't read the text. Please provide larger scans.

 

[hesham]

OK Stargazer,


but I divide it into two pieces.

 

[Stargazer]

Apparently only #6 and #9 are Lockheed (though I'm not sure about #7).
The author seems to have forgotten to indicate what #5 was...

 

[hesham]

Apparently only #6 and #9 are Lockheed (though I'm not sure about #7).
The author seems to have forgotten to indicate what #5 was...

Thank you Stargazer,


sorry for my late,for # 5,I think it was just a Model,and what about # 8 ?.

 

[toura]

Hi all From "aviation magazine n°836

 

[hesham]

Very cool my dear Toura.

 

[Jemiba]

N° 8 is said to be a German design, similar to the ROC (N° 7), which was a guided bomb (actually
built), although I couldn't find the manufacturer still yet.
The Lockheed Ringwing in N° 9 is interesting in so far, as here the ring, containing the ram jet engines
was rotating around the fuselage to stabilise the aircraft by the gyroscopic effect.

 

[Stargazer]

N° 8 is said to be a German design, similar to the ROC (N° 9), which was a guided bomb (actually
built), although I couldn't find the manufacturer still yet.
The Lockheed Ringwing in N° 9 is interesting in so far, as here the ring, containing the ram jet engines
was rotating around the fuselage to stabilise the aircraft by the gyroscopic effect.

You said the ROC was N°9, but then you said it was also a Lockheed!

 

[hesham]

Thank you my dear Jemiba,


and I think you meant BTZ VTOL aircraft;
http://www.secretprojects.co.uk/forum/index.php/topic,6662.msg102910.html#msg102910


For my dear Stargazer,yes you'er right,the # 9 was a Lockheed design,and may be it was a fighter,who knows ?.

 

[LGSAdeptusAeronauticus]

Hi all From "aviation magazine n°836

Looks sharp! Why is it or isn’t it a good idea

 

[Sundog]

Hi all From "aviation magazine n°836

Looks sharp! Why is it or isn’t it a good idea

Ring Wings would be more expensive to build than a standard wing, at least when built conventionally. There's also the issue of will there be enough roll damping. The biggest problem with them is the top part of the wing stalls before the bottom part of the wing which leads to pitch up issues. Also, for a given size they offer less lift than a standard wing. IIRC, for an equivalent span they develop 2/3 the lift. They offer lower induced drag, but if they have the third connection at the top there is more interference drag and probably more parasite drag as well.

 

[Hank58]

The concept shown in the clipping from that French Aviation Magazine n°836 was an early 1980s idea that came from the Lockheed Georgia Company's Advanced Design Department. I had the pleasure of working there for a time in the 1980s with the father of the ring-wing concept, Rollo Smethers (his real name). Rollo was a free spirit who had several unique design ideas, but some were only lightly tethered in physics and engineering. The ring-wing configuration stemmed from a slightly incomplete understanding of induced drag and wingtips. As is well understood, induced drag is the drag due-to-lift that stems from 3-d flow effects (i.e., in simple terms: "wingtips"). One way to think about that is to remember that 2-d airfoil wind-tunnel models (airfoil test models that span the tunnel test section completely, wall-to-wall) don't have induced drag. (Net up-wash equals net down-wash and the lift vector is vertical.) They essentially have an infinite aspect ratio. The fallacy of the ring-wing was that it wouldn't have induced drag because in one sense it doesn't have wingtips. Actually, however, the ring-wing behaves more like a biplane with two wings of low aspect ratio, one atop the other, interfering with each other. There is quite a bit of 3-d flow effect on the portions of the ring where it goes vertical. Structurally, the benefits of the "bracing" of the loop are also diminished because the lift loading does NOT put the ring in hoop tension. Finally, the more vertical portions of the loop produce a lot of skin-friction parasitic drag (from their wetted area) while not producing usable lift.

Rollo died at a young age of cancer. I look back at his influence on my design career and believe he championed "out-of-the-box" thinking before that term even existed.