Fisher P-75A Eagle
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johnbr
2nd Lieutenant
p-75a
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Nice shots!
I've read of this design before and, from what I recall Fischer-Body in an effort to avoid having to build B-29's for the US War Effort used it's connections to develop this "interesting" design (read "turd") instead.
From what I remember hearing, it was a real-life kit-bash (it's a model that's built out of parts of other models that often ends up looking stupid) made of either parts from other aircraft or parts inspired from other aircraft including: The landing gears, lifted off the F4U Corsair; the tail-surfaces, lifted off the SBD Dauntless; parts of the wing based on, and/or lifted outright off the P-40 Warhawk at first (and later P-51 Mustang) and; canopy based on/inspired by the P-40 Warhawk (and later a tear-drop design): At least the fuselage seemed to be a genuinely new design...
It was powered by an Allison V-3420 mounted amidships, driving an extension shaft connected to a pair of 3-bladed contra-rotating propellers. Despite the USAAF's typical interest in turbochargers, it actually used some form of supercharger instead. It was initially to be built as a fast climbing interceptor (projected climb-rate was 5000-5600 fpm), and later reconfigured into a long-ranged escort fighter.
It first flew November 17, 1943 (easy to remember as it's 40 years before I was born to the day) and had a variety of undesirable characteristics, such as the fact that they had miscalculated the center of gravity, it had bad spin-characteristics, and heavy ailerons.
The fact that the engines didn't produce as much power probably wasn't really all that useful either.
From what I remember hearing, it was a real-life kit-bash (it's a model that's built out of parts of other models that often ends up looking stupid) made of either parts from other aircraft or parts inspired from other aircraft including: The landing gears, lifted off the F4U Corsair; the tail-surfaces, lifted off the SBD Dauntless; parts of the wing based on, and/or lifted outright off the P-40 Warhawk at first (and later P-51 Mustang) and; canopy based on/inspired by the P-40 Warhawk (and later a tear-drop design): At least the fuselage seemed to be a genuinely new design...
It was powered by an Allison V-3420 mounted amidships, driving an extension shaft connected to a pair of 3-bladed contra-rotating propellers. Despite the USAAF's typical interest in turbochargers, it actually used some form of supercharger instead. It was initially to be built as a fast climbing interceptor (projected climb-rate was 5000-5600 fpm), and later reconfigured into a long-ranged escort fighter.
It first flew November 17, 1943 (easy to remember as it's 40 years before I was born to the day) and had a variety of undesirable characteristics, such as the fact that they had miscalculated the center of gravity, it had bad spin-characteristics, and heavy ailerons.
The fact that the engines didn't produce as much power probably wasn't really all that useful either.
wuzak
Captain
The P-75 came about because the USAAF suddenly realised they had a need for a long range escort.
As such it was an emergency program, which meant cutting corners wherever possible. So they used bits of other aircraft.
Before it was anywhere near available or in production, the P-51B came along and proved it could do the job.
The Fisher Body division of GM was not, as far as I am aware, going to be building B-29s. They were, however, contracted to design and build the V-3420 QEC module to fit in place of the R-3350 on the B-29. This was initially trialled on the XB-19 and then was fitted to the XB-39.
Unfortunately, the P-75 program delayed the first flight of the XB-39, after which it was determined that it would be no longer required.
As such it was an emergency program, which meant cutting corners wherever possible. So they used bits of other aircraft.
Before it was anywhere near available or in production, the P-51B came along and proved it could do the job.
The Fisher Body division of GM was not, as far as I am aware, going to be building B-29s. They were, however, contracted to design and build the V-3420 QEC module to fit in place of the R-3350 on the B-29. This was initially trialled on the XB-19 and then was fitted to the XB-39.
Unfortunately, the P-75 program delayed the first flight of the XB-39, after which it was determined that it would be no longer required.
johnbr
2nd Lieutenant
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T Bolt
Colonel
Some pictures I took of the one at the Air Force Museum in 2012
vikingBerserker
Lieutenant General
Nice! That section was closed when I was there, I missed the B-70!
T Bolt
Colonel
I think they've moved most of aircraft in the Presidential and Research & Development hangers over to the newly constructed hanger at the main museum complex. I haven't been there since it opened but hope to get there to see it some time this winter.
johnbr
2nd Lieutenant
The General Motors P-75 turned out to be a short-lived, long-range escort fighter; the contract for 2,000 of them was cancelled.
P-75A), with its contra-rotating propeller, was a big airplane—too big, in General Bradley's opinion.
Through General Motors, the P-75 project had been launched in late 1942. To get into production quickly, the plan was to use, as far as possible, parts already in production for existing aircraft. The double Allison V-3420 24-cylinder engine and a double rotating propeller were to be the only new features. The wings were to come from the P-40, the center section from the Navy's Vought Corsair FU-9, the tail from Douglas' A-24 bomber. With an initial order of 1,000 planes, General Motors had started production on an emergency basis at its Fisher Body Plant in Cleveland. Anxious to fly the P-75, I lost no time in getting to Cleveland to take it up.
The airplane, with its contra-rotating propeller, was a big one—too big. It was heavy, and worst of all, clumsy and unstable. If it had been able to go the required distance, it never could have defended itself. No fighter pilot would endorse it, I was certain. To me, it was hopeless.
I returned to Wright Field more determined that ever to resume my project of extending the range of the P-51. Given enough time, certain defects of the P-75 could be corrected, I knew, but there was not enough time. As I look back today, I am certain that its weight, excessive size and basic instability would have prevented the P-75 from ever being a successful fighter.
Before going to Cleveland to fly the P-75, I had gone out to the hangar to do a little -simple barnyard research on the P-51 configuration. At that time the P-51 had about 200 gallons of fuel in its wings and we were adding two 75-gallon drop tanks, one under each wing. But to go to Berlin, fight and get back to England safely, it needed more internal fuel. I looked behind the pilot's seat and found only the plane's two radios, the IFF ("identification friend or foe") and the VHF. It was obvious that a tank of considerable gallonage could be put there if the radios were moved to another location but, as you may have guessed, it wouldn't be that simple.
I knew that North American engineers had considered putting a gas tank back of the pilot's seat and had discarded the idea because of fear that a full tank would cause a dangerous shift aft of the center of gravity. The danger was there, I knew only too well, but I had come back from Europe swearing to right a desperate situation and was convinced that it was going to take audacious, if not downright extreme measures. I figured that a full tank of eighty to ninety gallons might well require two hands on the stick for takeoff and climb, and perhaps for a considerable time thereafter. But it seemed logical that after the climb-out and cruise over the North Sea, the weight of the fuel would be sufficiently reduced to assure a return to normal stability. I was just this far along in my thinking when I went to Cleveland to fly the P-75. Upon returning to Wright Field, I went immediately to see General Orval Cook, then head of the Production Division and my immediate boss.
"Orval", I said, "I am just back from flying the P-75 and I cannot believe what I've heard! We've ordered 2,000 of them
The P-51 Over Berlin, by Mark E. Bradley
P-75A), with its contra-rotating propeller, was a big airplane—too big, in General Bradley's opinion.
Through General Motors, the P-75 project had been launched in late 1942. To get into production quickly, the plan was to use, as far as possible, parts already in production for existing aircraft. The double Allison V-3420 24-cylinder engine and a double rotating propeller were to be the only new features. The wings were to come from the P-40, the center section from the Navy's Vought Corsair FU-9, the tail from Douglas' A-24 bomber. With an initial order of 1,000 planes, General Motors had started production on an emergency basis at its Fisher Body Plant in Cleveland. Anxious to fly the P-75, I lost no time in getting to Cleveland to take it up.
The airplane, with its contra-rotating propeller, was a big one—too big. It was heavy, and worst of all, clumsy and unstable. If it had been able to go the required distance, it never could have defended itself. No fighter pilot would endorse it, I was certain. To me, it was hopeless.
I returned to Wright Field more determined that ever to resume my project of extending the range of the P-51. Given enough time, certain defects of the P-75 could be corrected, I knew, but there was not enough time. As I look back today, I am certain that its weight, excessive size and basic instability would have prevented the P-75 from ever being a successful fighter.
Before going to Cleveland to fly the P-75, I had gone out to the hangar to do a little -simple barnyard research on the P-51 configuration. At that time the P-51 had about 200 gallons of fuel in its wings and we were adding two 75-gallon drop tanks, one under each wing. But to go to Berlin, fight and get back to England safely, it needed more internal fuel. I looked behind the pilot's seat and found only the plane's two radios, the IFF ("identification friend or foe") and the VHF. It was obvious that a tank of considerable gallonage could be put there if the radios were moved to another location but, as you may have guessed, it wouldn't be that simple.
I knew that North American engineers had considered putting a gas tank back of the pilot's seat and had discarded the idea because of fear that a full tank would cause a dangerous shift aft of the center of gravity. The danger was there, I knew only too well, but I had come back from Europe swearing to right a desperate situation and was convinced that it was going to take audacious, if not downright extreme measures. I figured that a full tank of eighty to ninety gallons might well require two hands on the stick for takeoff and climb, and perhaps for a considerable time thereafter. But it seemed logical that after the climb-out and cruise over the North Sea, the weight of the fuel would be sufficiently reduced to assure a return to normal stability. I was just this far along in my thinking when I went to Cleveland to fly the P-75. Upon returning to Wright Field, I went immediately to see General Orval Cook, then head of the Production Division and my immediate boss.
"Orval", I said, "I am just back from flying the P-75 and I cannot believe what I've heard! We've ordered 2,000 of them
The P-51 Over Berlin, by Mark E. Bradley
Lovely shots!
I'm curious why they would take on this program rather than just build the B-29 nacelles? The only thing I can think of is that they can say "I built my own design" rather than build parts of another aircraft.
GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
General Motors had contracts building the TBM, Wildcat (FM) via Eastern Aircraft and Fisher was building major B-25 assemblies and components to the B-29.
By taking on the priority XP-75 project, GM avoided being forced to manufacture complete B-29s at Fisher.
The amount of wartime material and equipment GM was manufacturing at the time was staggering, too. They simply did not want to make B-29s.
By taking on the priority XP-75 project, GM avoided being forced to manufacture complete B-29s at Fisher.
The amount of wartime material and equipment GM was manufacturing at the time was staggering, too. They simply did not want to make B-29s.
But why did they have a problem with making components to the B-29, yet were okay with creating this design?
GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
They had no problems with making B-29 components, as the Fisher plants were producing components for a variety of types.
But the Government wanted them to manufacture complete B-29 aircraft - so the XP-75 project blocked the Government from forcing Fisher to manufacture the B-29.
In otherwords, the XP-75 was never really a serious project for GM, even though it actually is an attractive aircraft in spite of it's terrible performance. It was a means to keep the Government from overloading them with a massive project, since they (all of GM's firms and subsidiaries) were working at full capacity.
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