Vought V-173 & XF5U: The Experimental "Flying Pancakes"

In this video, we discuss two experimental WWII fighter planes, the Vought V-173 "Flying Pancake" and the Vought XF5U Flying Flapjack". We also discuss why these planes were built with their uncommon and unique designs, how successful they were, and why they failed to be adopted by the US Military.
Links:
Full Video of Flight: • Vought V 173 Flying Pa...
Video Mentioned @ 12:50 or so: • The R-40C Three: Ameri...

[@JFrazer4303]

While working for NACA, in the early '30s, Zimmerman was on the team that saw the Arup S-2 from Indiana perform, and later wrote that he chose the very-low aspect-ratio planform as the starting point for his work on a VTOL tail-sitter, though neither the V-173 nor the XF5U had enough power nor appropriate landing gear. The military like everyone else ignored the Arup planes which were entirely successful flying machines and did everything that the later Vought planes did. NACA tunnel tests with the V-173 showed that it didn't gain anything with the wing-tip mounted outward spinning plane-changing props versus normal props, and the extra complexity of the drivetrain gave the V-173 problems and stopped the XF5U from getting close to flying. The situation with the props hampered it and was not necessary. Why the Navy ignored the Arup and other similar planes and built Zimmerman's digression is a mystery. See also the Eshelman, commonly known as the flying flounder, for another, better STOL and fast & simple all-wing / lifting body plane which the Navy ignored. It's a myth that the very-low aspect-ratio gave it high induced drag from wing-tip vortices. The huge vortices are elective and temporary, for flying very slowly and being stall-proof. The vortices disappeared when flown normally, and the Arup, the Eshelman, and the circular wing Nemeth parachute plane and others have proven the type to be sleek and quick on available power. Zimmerman did not use the props to supposedly counter the vortices. That's another part of the myth behind it. The advent of jets didn't kill it: the US military used piston-prop combat planes into the '70s, for support into the '80s and still fly props. The very-low aspect-ratio like the Arup or Eshelman would have been awesome with jets, would have outperformed everything flying then or for the next decade. They looked funny and nobody took them seriously, and the misconceptions about them having high drag at cruise and needing wing-tip mounted, overly complex props have caused decades of misinformation about them.

[@willrogers3793]

Loved this thing in Secret Weapons Over Normandy 😊

[@fallingwater]

I wonder how this design would fare with modern engines and avionics. Seems like a great idea that should have been further developed - I'm thinking turboprops, or maybe even turbofans in the frame...

[@aldenconsolver3428]

I think that with folding gear and 2 250 horse engines that this thing could be a flying thing to go anywhere, land anywhere and take off in no feet. It might even make a heck of a bush plane.

[@anthonybeers]

it it fun to fly these as poster board RC planes with high alpha. I would not say they really fly well though.

[@ErikssonTord_2]

@@aldenconsolver3428 To get enough yaw stability at high alpha would be tricky in turbulent air! And with nil forward view, how would a pilot know where he was going when taxying, without a lot of help?! Definitely not suitable for bush use!

[@JFrazer4303]

​@@ErikssonTord_2 Many of the sort have not experienced instability or difficulty with control at up to 40 degrees "A". Many planes with poor or no forward and downward visibility have been flying for decades. Every 2-seat biplane, crop dusters, the Corsair, the P-47, many others. Several planes of very-low aspect-ratio have had excellent visibility. Arup S-4, Eshelman, Payen AP-10, Hatfield "Little Bird", Wainfan "Facetmobile", others.

[@PRH123]

What would be interesting nowadays would be 4 or 5 electric motors across the front, to provide the airflow for the “blown wing.” Smaller diameter props would allow it to have shorter gear, a lower ground stance, and better visibility on the runway and when taxiing. Would make it safer to be around on the ramp as well. Would also relieve the need to cross shaft the engines, which would save a lot of weight and complexity. Instead of a huge battery pack, provide the power from a small engine buried in the fuselage. Could be piston, rotary, etc. Ala the E-STOL concept. As an engine providing power still has to work thru a battery, you’d have a much smaller battery, that would retain enough charge to get down quickly in event of an engine failure.

[@jamess3241]

That forbidden pancakes line had me laughing so hard I almost wrecked my car

[@ErikssonTord_2]

It was Charles Lindbergh that crashlanded the V-173 on the beach!

[@JFrazer4303]

That's not proven, He flew it, but we'd need to see any factual sources that it was he who lost power and forced landed.

[@dantejones1480]

The only 'plane' in existence that just stubbornly, determinately, fanatically refuses to stall.

[@JFrazer4303]

Not the only. Not by far. See the '30s Arup planes from Indiana, which Zimmerman copied for this. See the '30s Nemeth parachute plane and the similar Farman 1020. See the Payen AP-10 from the '30s. The Eshelman "flounder" from the '40s. The '90s Wainfan "Facetmobile" All stall-proof, most demonstrated steep 45° climb, super-STOL.

[@aldenconsolver3428]

The fact that the V173 would fly with only 2 80 hp engines with labyrinthian gearing and huge protruding landing gear the shape still has interest to me. folding gear and 2 300 hp Lycoming might make a an actual VSTOL craft for the everyman. Or at least might make a drone body with better performance than the current generation. Whenever I see that thing I have the urge to go out in the garage and start fiddling.

[@ihyls]

I still think the fact that it worked as well as it did for how radical the design was at the time is still incredibly impressive. I would imagine that with the technology we have today, it certainly would be possible to make something like it that didn't have the vibrational issues. I can't imagine that any aircraft manufacturer would really want to try and make something like it today as a consumer product, though, as it probably would only be sold to an incredibly niche market, so it wouldn't make monetary sense for the company to even make it. Would absolutely love to see someone with money to burn make a modernized version of the V173. It would probably be really interesting for airshows and stuff.

[@Cuccos19]

@@ihyls Although rather reminds the German AS-6 aircraft, but the Australian home built "David Rowe UFO (called the Useless Flying Object) actually files nicely. kzbin.info/www/bejne/d5q5kItumdN5fck kzbin.info/www/bejne/m3fKo2xmgdSVd7M

[@JFrazer4303]

​A super-STOL plane that is stall-spin proof and efficient on low power always has interest. They look funny, and "If it looks right it'll fly right" is taken as a hard and fast rule. There are very many misconceptions about the very-low aspect-ratio planform,, many are spurred by the Vought/Zimmerman digression with the wing-tip mounted outward spinning plane-changing props (which NACA tests showed didn't help it).

[@spindash64]

It could also be developed into a phenomenal new Cropduster, sharing many of the strong points of Biplanes, but with the added bonus of less drag, meaning more spray can be carried rather than fuel

[@warnock0721]

Back in the 70s there were published plans for the V-173 for the control line model event called Navy Carrier. Never actually one at any contest though..

[@IMSawyer92]

I'm going to have to do a mini-presentation in my Aircraft Design class, and this will help greatly. Been looking at the flying pancake as my plane of choice and all of this information helps to cement that possibility.

[@JFrazer4303]

Look at the Arup planes from Indiana in the '30s, which were the intellectual forebears of this, and did better as flying machines. See the '80s Hatfield "Little Bird", which were follow-ups to the Arup. See the '30s Nemeth parachute plane. The similar Farman 1020. The '30s Payen AP-10. The '90s Wainfan "Facetmobile".

[@mummakesitizzy]

Very informative video, good to know a bit of these amazing planes

[@douglasthecorgi2568]

I wonder if this plane would have had a chance in the jet era if they had tried to convert it into a turboprop. I also wonder how maneuverable it would have been in combat. As long as it didn’t slow down too much from extended turns (though, with those props, I imagine it would’ve had great acceleration), I like to imagine it could have easily kept up with a Zero. And, had this plane made it into production, with its STOL capability and all that lift for ordnance, I imagine it could have found a niche in CAS during Korea with the Marines, or even the Air Force.

[@anthonyevans7718]

love your content

[@kylenolan3138]

Your pancake eating preferences are mild compared to those of my great grandfather who preferred a mixture of brown sugar and mustard.

[@alwaysstraddling]

I'm not sure I can continue after pancake and ranch were used in same sentence

[@peterkordziel7047]

Well mea culpa.looks like egg on my face. That's what happens if you sound off half cocked. Extremely well researched document..

[@davidmurphy8190]

Back in 1968 (?) AIR CLASSICS did a great article on the Vought Pancake concept.

[@thebeefbastard_]

It actually looks like a pancake.

[@SatelliteYL]

What is the name of the plane at 0:56 in the top left? I have seen another video with it flying but it didn’t mention the name either, curious what it’s called

[@bacongod4967]

Had less hp than the as-6 yet flew whereas the as-6 couldn’t. Nice.

[@JFrazer4303]

See also the predecessors of all of them, the Arup planes from Indiana. Sleek on little power - notably not draggy. The Sack needed more "A" to take-off, but they didn't have time to move the landing gear further back and put a nose-wheel under it, to keep it from tipping forward.

[@Akumasama]

Apparently some people are looking into making an electric version of the flying pancake. I can see how that would be a better idea than... you know, having your drive shaft do 2 90 degrees turns from the piston engine generating power. Paper reference: DOI: 10.2514/6.2017-1184 'course, access is paywalled. -_-

[@411NEWS]

Lol funny commentary :)

[@peterkordziel7047]

Actually, it was a Flying FLAPJACK. That's what I've always heard it called. Means the same thing,though. But it's very jarring hearing it called a pancake.

[@IMSawyer92]

initial version was the pancake - second iteration was the flapjack

[@PRH123]

Imagine if they called it the crepe, or the tortilla… :)

[@Grimmsha72]

Honestly I think it looks way more like a turtle then a pancake.

[@beastboy0078]

strange taste you say 🤔. Chocolate Flavored Scrambled Egg. yes, I cook this. yes, I eat this too on occasion.

[@tombouie]

Thks & sooooooooo for a given wing width; If a wing with a little longer chord-width has a little more lift, then a wing with an extremely longer chord-width has an extremely more lift. Sooooooo ???How well/pratical will extending wing chord-width scale???

[@ErikssonTord_2]

The drag increases with wetted area, so from an efficiency standpoint, under Mach 1, you'd want higher aspect ratio, not lower, and then you need a tail much bigger and that's add drag as well. If you have unlimited power things are very different, of course.

[@tombouie]

@@ErikssonTord_2 Thks