Rear folding undercarriage on single engined aircraft

[WJPearce]

There is a distinct advantage to having the main gear exposed when retracted.

The A-10 has that purpose-built feature, so that if it's tricycle gear fails to extend, it still has conventional gear to land on.

This series of photos was one such instance, that happened at Edwards AFB.

Interesting photo. Whoever added the wheel chalk is the true ace of the base. But the A-10 did prang its nose.

 

[BiffF15]

Interesting photo. Whoever added the wheel chalk is the true ace of the base. But the A-10 did prang its nose.
View attachment 654895

I noticed the gun problem as well but think it's an internal failure, rather than from impact. Look at the sensor that's undamaged, and no evidence that I can see of nose impact with the runway. The gun is huge, probably came apart internally, and resulted in self inflicted damage that caused the gear to fail to extend.

 

[GrauGeist]

The GAU-8 suffered a failure that rendered the nose-gear inoperable, so the pilot kept the main gear up, taking advantage of the redundant design.

This happened another time, in Michigan, where the GAU-8 failed and the pilot had to land gear-up. The difference in this instance, was the gun's failure also blew the canopy off, forcing the pilot to emergency divert to a nearby GA airport.

 

[GreenKnight121]

I have no idea what they were planning do with the Plane during initial design and testing.

This is the key to the A-1 Skyraider... we should rather say XBT2D-1!

Yes, the Skyraider was originally designed as a combination dive/torpedo bomber (as was the Martin Mauler) - which required that the under-fuselage and inner wing areas be clear of all centerline weapons during takeoff & landing... and they also wanted the maximum under-wing area clear for weapons stations (at that time including many 5" rockets on individual "zero-length" stations, as well as large numbers of smaller bombs).

 

[emu27]

The SAAB 17 were meant to use them as airbrakes during dive bombing attacks.

 

[FLYBOYJ]

Something else to consider that's been left out of this discussion - Center of Gravity, where the designer wants the C/G envelope to sit when fully loaded and empty/ gear up and down.

 

[Greg Boeser]

Yes, I've seen that mentioned in pilot's manuals before. Not the rationale for rear folding vs inward or outward folding, but the difference in cg for gear up or down.

 

[SaparotRob]

Deja vu.

 

[Blitzen]

I don't see the tailwheel Bellancas mentioned yet. I own a 14-13. It has a fold-back gear with about 50% of the wheel showing.
Since it is a real orphan - no support whatever, I had thought(day dreamed) of what changes one could make building one from scratch as an experimental. It would make ownership a lot more manageable, even having my A&P.

Since it has a swing back retractable gear, would some different gear config be better? Hard to say. A modified wing with a more common swing-in gear would need an extended leading edge at the root - a la P51 - to house the retracted wheel and extra internal structure out to the pivot. However, the doors would be simple and drag minimum.

The challenge for the simple swing back gear seems to be getting it all covered up after it is retracted. It is usually a heavy compromise of complexity-reliability and drag. But even if perfect aerodynamically the protruding surface is extra wetted area.

A little speck of history. I knew the late Art Scholl way back when. His modified Super Chipmunk had a rear folding Bellanca gear and Petten fairing, a geared Lycoming and a big Aeromatic prop, all items I suggested. After he had flown it, he discovered that the hydraulic system could not keep the gear from popping out during high G maneuvers. So, I designed, built and installed some up-locks for it. I think that aircraft is now hanging in the National Air Museum.

Ron

 

[davparlr]

The SAAB 17 were meant to use them as airbrakes during dive bombing attacks.

View attachment 654923

I believe the F4U could also do this.

 

[davparlr]

This is the key to the A-1 Skyraider... we should rather say XBT2D-1!

Yes, the Skyraider was originally designed as a combination dive/torpedo bomber (as was the Martin Mauler) - which required that the under-fuselage and inner wing areas be clear of all centerline weapons during takeoff & landing... and they also wanted the maximum under-wing area clear for weapons stations (at that time including many 5" rockets on individual "zero-length" stations, as well as large numbers of smaller bombs).

Maybe the gear could be used as airbrakes for dive bombing?