Airborne Awesomosity

Guest Post: Saddle Up


[We have been fighting an unusually dense influx of spam comments lately, as we have mentioned before (still over 300 a day!), but there have been a few surprise legitimate comments in amongst the clutter. When someone links to one of our posts, that link back can be shown on Toasters, if we approve it. Last week I found a link to one of Fodder’s posts about the Allison V-3420; the linked post being the inaugural post on a little blog called Big Prop. It was a write up on the Fisher P-75 Eagle (a topic also nicely discussed by Fodder in his post on How to Get Out of a Contract!), and I asked the gentleman writer, known as Dubois1985 if he would be interested in running it as a guest post over here, as I felt his storyline angle was different enough from Fodder as to offer up 2 entertaining perspectives for you all. Here is a sort bio he sent for introductions all around:

I’m Dubois1985, a writer and blogger. I’m a massive fan of anything to do with Dieselpunk and World War Two aircraft as well as Batman, Judge Dredd and really bad films.

He also appreciates a good horse metaphor. Enjoy!]

The Japanese were about to come over the horizon any minute. People already thought they’d seen them over Los Angeles. America’s fighters were either ageing horses or else horses that only had three legs. What it needed was a raging stallion with all the power the best engines of 1942 could provide, a ceiling of 38’000 feet and the fastest possible rate of climb between that ceiling and the ground.

It just so happened that General Motors had one of the finest engine manufacturers in the whole United States. Allison.

Fisher P-75 Eagle

Allison had produced the V-1710 which had been mated with planes from across America and Europe, though only Curtiss had provided anything of worth with the P-40. So when it came to creating a stallion General Motors had the perfect company to provide the engine since Allison had derived the V-3420 by combining two V-1710′s to make a new engine. As to the company which would create the horse the V-3420 would power, General Motors entrusted this to Fisher. Fisher didn’t have any experience when it came to making stallions, their main calling being body work for GM’s cars so they hired Curtiss’s best designer, Donovan R. Berlin.

To create the best stallion he could in the shortest time possible, Berlin picked out parts from some of the best  aircraft flying in American skies. Wing panels from the P-51, later the P-40; tail parts from the Douglas Dauntless dive bombers and the undercarriage from the Vought Corsair.

The beast that emerged from this, the Fisher P-75 Eagle, was a strange looking animal with a short mane of a cockpit leading down a long body to end in a rather large tail. When it came to the kick this buckaroo carried ten fifty calibre machine guns to shred its way through any opposition. Rolled out to a wave of publicity, the beast was shown to the public with even its designation of P-75 being seen by GM as an advertising tool. Before long though this horse began to show worrying signs of being lame.

The first came from the V-3420, which failed to develop the promised three thousand horsepower. Without that horsepower, the Eagle’s legs proved to be too short to support it. The second was that America no longer needed interceptors.

Japan had been on the back foot since Midway and American bombers were joining the British in pounding the Reich to rubble. Escort fighters were in vogue now which meant the horse needed to be re-shod. Fisher redesigned the P-75 and the USAAF awarded a contract for 2’500 of them, after inserting the ‘if its lame we bolt’ clause into the contract.

Fisher P-75 Eagle

That moment came a year later. Mustangs were charging across Germany and a whole new breed of horse would be soon be joining them with the onset of the jet age. No one needed another piston engined fighter especially when it’s engine couldn’t keep all the cylinders firing. None of the other piston engines then in development could provide the power the V-3420 managed to put out even after failing expectations.

The Army duly decided not to go against the odds in the derby, betting instead on sure-fire bets like the P-51 and P-80, so all but eight P-75As were cancelled. These were ordered simply to test the V-3420 which still had the confidence of firms like Boeing and Lockheed. As for Berlin he went on to McDonnell in 1947 while Fisher went back to making body parts for GM’s cars.


As for the P-75′s, three crashed but one of them has survived for people across America to come and see the sole surviving example of this strange beast pay silent tribute to its fallen brethren in the USAF Museum at Dayton, Ohio.

The Eagle was a bold attempt to design a fighter by combining parts from some of the best aircraft to produce a superior plane, just as horse breeders attempt to use material from the best horses to create a better bloodline. Its a brilliant example of how American industry responded to the changed world that came into being after Pearl Harbour. It deserves to be remembered as more than just another failure.

All photos courtesy of Brett Stolle and USAF Museum in Dayton, Ohio.

  • The Professor

    Nice article! That's some good stuff, and we like our good stuff here.

    A word to our commenters: While we're dealing with the huge influx of spam, there is a distinct possibility (and in my case, a certainty) that a legitimate comment waiting for moderator approval might get accidentally marked as spam and dumped. If you think that has happened to one of your comments, please try again, and hopefully eyes better than mine will catch it.

    To Plecostomus: I accidentally dumped one of your comments and couldn't find it again in the spam queue. Evidently I vaporized it, a bad habit of mine. My apologies.

  • skitter

    Was the double-Allison eventually used in any of the big bombers?

    • Effef

      Nah, it never really overcame its teething issues. By the time it was getting close jets were in vogue and getting better, so it was canned.

    • fodder650

      Like Skitter said it never got used but there was a lot of complexity issues as well. The amount of gearing they did with it was simply amazing. They used it in dozens of prototypes several of which I have featured. Such as a V-3420 engine version of the B-29 known as the B-38 Lincoln and even a P-38 variant known as the Chain Lightning (XP-49 or XP-58 if my memory is correct) that, effectively, made it a four engined fighter. I can get the links to my articles if you would like. The Germans also were using coupled engines but put one in production by putting two Daimler Benz DB-601's together as a DB-610 and used two of these to power the HE-177 Greif. Which I covered in at least one post. Had the Germans just started the HE-177 out as a four engine aircraft like the Condor it would have been far more effective.
      As for the the Fisher. I would look forward to going back and forth with the author on this because I do find it a very interesting topic. Was it a trojan horse used by GM to get out of making bombers because their factories were already overly stressed or was it a good idea that failed.

      Here is an Allison V-3420 out of the aircraft.
      <img src="; width=500 />

      <img src="; width=500 />