The history of circular wing aircraft can be traced back to the early days of aviation, with pioneering experiments in closed-wing designs. Some key milestones in the development of circular wing aircraft include:
1. Bell Riot aircraft: One of the earliest examples of a circular wing aircraft, the Bell Riot featured two annular wings mounted in tandem[5]. Later versions replaced the forward annular wing with a biplane design and added a Canard, making it a three-service aircraft[5]. Unfortunately, the Bell Riot was damaged beyond repair during its initial tests[5].
2. Lockheed Ring Wing: The Lockheed Ring Wing, also known as the Lockheed Ring-Winged Aircraft, was a futuristic design inspired by early aircraft concepts in France[3]. The aircraft was designed to generate significantly more lift due to its continuous circular wing, resulting in reduced fuel consumption and a lighter load[3]. However, the innovative lift generation system led to an unexpected increase in drag, essentially nullifying its fuel-efficiency benefits[3].
3. Sack AS-6: During World War II, several disc-shaped aircraft were proposed by aircraft designers in Nazi Germany[4]. One of the few to make it further than the drawing board was the Sack AS-6, an experimental light plane with a round-winged plan form that first flew in 1944[4]. The Sack AS-6 was a German prototype circular-winged aircraft built privately during the Second World War[11]. Despite several attempts at flight, the AS-6 never achieved flight and was considered dangerous due to various issues, such as defects in the aircraft’s control surfaces and stability problems[11]. The aircraft had a wingspan of 16 ft 5 in (5 m) and was powered by a 10C-3 engine[12]. The AS-6’s poor performance and inability to fly were attributed to its design and the use of salvaged materials during its construction[12]. Some sources suggest that the aircraft’s circular-wing design might have offered some advantages, but its performance was never tested due to the issues mentioned above[12]. After the war, Arthur Sack, the designer of the AS-6, passed away in the mid-1940s, and his work was never implemented in mass production[12].
4. V-173: The Vought V-173 “Flying Pancake” was an American experimental test aircraft built as part of the Vought XF5U program during World War II. The aircraft was designed with a “circular” airfoil (at least in the front) with large-diameter propellers on the wing tips, which minimized drag and allowed it to take off and land at exceptionally low speeds and still have good high-speed performance. Although it was completed, it was never flown; the Navy cancelled the project because of its decision to switch to turbojet engines[16][17][19]. However, the V-173 proved Zimmerman’s ideas to be practical and the Navy was so impressed with the project that it ordered the construction of the Vought XF5U-1, which was substantially the same design[16]. Charles Lindbergh, the first man to fly solo across the Atlantic Ocean, piloted the V-173 “Flying Pancake” on several occasions and found it very responsive[18]. The V-173 “Flying Pancake” is now on display at the Frontiers of Flight Museum in Dallas, Texas[18][20].
5. Vought XF5U-1: The lone XF5U-1 underwent ground runs and short “hops” that were not true flights, but no serious test flights were attempted. The aircraft was based on a wing of circular shape, which served as the ‘fuselage’ and was designed to be capable of vertical take-off and landing, as well as very high-speed flight. The specifications for the XF5U-1 fighter were promising, with the potential for great maneuverability and speeds up to 452 mph (727 km/h), but the XF5U-1 was eventually cancelled in 1947 due to its technological battle as well as ballooning program costs. The lone XF5U-1 underwent ground runs at Vought’s Connecticut factory. However, it never overcame vibration problems and did not achieve true flights. The project was canceled on March 17, 1947, and the prototype aircraft (V-173) was eventually transferred to the Smithsonian Museum for display.
Conclusion
Despite these early attempts, circular wing aircraft have not yet been successfully implemented in commercial aviation. The Lockheed Ring Wing, for example, never took off[5]. However, advancements in technology and aerodynamics may one day lead to the realization of circular wing aircraft, offering improved efficiency and reduced environmental impact[5].
Citations:
[1] https://youtube.com/watch?v=UzzQgsTqU8E
[2] https://patents.justia.com/patent/D274999
[3] https://www.techtimes.com/articles/298373/20231106/futuristic-lockheed-ring-wing-plane-uses-less-fuel-regular-aircraft.htm
[4] https://www.magzter.com/stories/Flying-Aviation/Global-Aviator-South-Africa/Strange-Technologies-Circular-Wings
[5] https://thetravelbible.com/the-lockheed-ring-wing/
[6] https://patents.google.com/patent/US20100102174A1/en
[7] https://news.ufl.edu/archive/2008/06/university-of-florida-professor-designs-plasma-propelled-flying-saucer.html
[8] https://www.popularmechanics.com/space/a3404/4269027/
[9] https://www.wired.com/2008/06/real-flying-sau/
[10] https://www.upi.com/Science_News/2008/06/16/Engineer-invents-a-flying-saucer/68671213636479/
[11] https://en.wikipedia.org/wiki/Sack_AS-6
[12] https://plane-encyclopedia.com/ww2/sack-as-6/
[13] https://youtube.com/watch?v=QbGZfRFZQCs
[14] https://youtube.com/watch?v=XRgNH2r5www
[15] https://modelingmadness.com/review/axis/luft/grosas6.htm
[16] https://airandspace.si.edu/collection-objects/vought-v-173-flying-pancake/nasm_A19610120000
[17] https://en.wikipedia.org/wiki/Vought_V-173
[18] https://www.flightmuseum.com/explore/chance-vought-v-173-flying-pancake/
[19] https://www.usni.org/magazines/naval-history-magazine/2019/june/pancake-didnt-fly
[20] https://www.smithsonianmag.com/air-space-magazine/restoration-vought-v-173-7990846/
[21] https://oldmachinepress.com/2017/02/05/vought-xf5u-flying-flapjack/
[22] https://www.militaryfactory.com/aircraft/detail.php?aircraft_id=1128
[23] https://en.wikipedia.org/wiki/Vought_XF5U
[24] https://www.usni.org/magazines/naval-history-magazine/2019/june/pancake-didnt-fly
[25] https://ww2aircraft.net/forum/threads/vought-xf5u-flying-pancake.47326/page-2
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