One must ask oneself - with the unavoidable drop in rate of fire from the synchronised guns (because they can't be firing all the time), would one even get the same rounds per minute into the sky as the P-47 could with two less barrels?sealordlawrence said:Synchronising 4 machine guns to fire through a 6 bladed contra-rotating propeller must have been fun! That said, the 10 .50 cal armament would have been devastating.
Power would be about right but the shafting would be completely different.Archibald said:Could that machine have be re-engined with a Sabre engine ?
Thank you!!!jzichek said:Just posted a new article at RetroMechanix.com presenting a very rare 51 page document on the Fisher P-75 Eagle:
It contains numerous high resolution detail photos and drawings of this flawed but not entirely unappealing aircraft, one of a handful of types powered by the mighty 24 cylinder Allison V-3420. Many of the photos are heavily retouched and portray an interesting intermediate stage between the original XP-75 and the final P-75A, retaining the Douglas-style tail of the former but having the bubble canopy of the latter. Ideal information for the modeler, historian, or general enthusiast wishing to get an in depth look at GM's failed foray into fighter aircraft design.
Not as difficult as you might think. I worked it out some time ago by drawing it in my AutoCAD. As simply as possible, the props were geared in the remote speed reduction unit so would be 'timed' to the gun synchronization. It would just be like it had just one 3-blade prop. I've even worked this out for two 4-blade contra-prop arrangement. The diagram below show the blades only moving 60 degrees of rotation, so times this by three for one complete rotation.pathology_doc said:sealordlawrence said:Synchronising 4 machine guns to fire through a 6 bladed contra-rotating propeller must have been fun! That said, the 10 .50 cal armament would have been devastating.One must ask oneself - with the unavoidable drop in rate of fire from the synchronised guns (because they can't be firing all the time), would one even get the same rounds per minute into the sky as the P-47 could with two less barrels?Johnbr said:I would love to see how they did it.
I don't know. But the story makes perfect sense (of a sort). Commercial motives and profiteering were common enough in WW2, as they were in wars before and after. A native design using its own engines (Allison was a GM subsidiary) would have offered higher profits than licensing a Curtiss-Wright powered, Boeing designed airplane.Sherman Tank said:Does anyone know if the oft-told story that Fisher and GM created the P-75 was to avoid having their factory assigned to build B-29s in any way true? I suspect it isn't because it doesn't make much sense but I've never seen evidence either way besides anecdote.
No , all issues was fixed with a great delay of flight of P-75A . In anyway scenario was changed and there were aircraft like P-38 with an awesome range .The P-75 to me is quite a fascinating aircraft, in it's final form where it was a new airplane (versus one made from various parts of other aircraft). It's a shame the final product failed to meet the original specifications by such a large degree.
Did Fisher have any plans for an XP-75B or P-75B to make up some of the lost performance? Was there any avenue to do so other than increasing engine power?
The P-75 had air-cooled exhaust manifolds. A jacket surrounded the exhaust manifold and air was fed through that jacket. The air entered through the ram-air scoop and exited via the area around the exhaust pipes.I can understand the radiator position of this aircraft.
Perhaps this picture shows ram air intake and exhaust nozzle. Inline..........
Very hard question indeed.Just for the sake of asking, how would the P-75a have fared against the TA-152h series in the escort role?