Bell XFM-1 Airacuda

[YGBSM]

You're right. I can't find any designation for the circular proposal, but the idea appears to have been started by a letter written in early 1935 by Captain Harry A. Johnson to Major General Benjamin Foulis recommending a heavily-armed super fighter capable of destroying bombers. The new plane would have the new designation "FM" for "fighter, multi-place".

Both Bell and Lockheed were issued $25,000 contracts to submit preliminary designs with a deadline of March 15, 1936. Bell won the competition by four-tenths of a point, 72 to 71.6 out of a possible 100. The Airacuda was set ahead by its twin cannons to the Lockheed's one. The Lockheed aircraft's designation was XPB-3 and later XFM-2.

Interestingly, the designer of the Airacuda for Bell was a former project manager at Lockheed.

Another humorous note - before the war, Bell visited the Messerschmitt factory in Germany and questioned what a long line of prototype Me-109s were for - to which Willi Messerchmitt quipped, "What is the Airacuda for?"

 

[YGBSM]

Also, I didn't know this was a thing - a tail-dragger version of the P-39 with a tailhook - officially the XFL Airabonita:

Source: Bell XFL Airabonita - Wikipedia

 

[Zipper730]

At least I've found a picture, though I have no idea of how it's performance would compare: Supposedly the FM-1 only narrowly beat the design out.



Frankly, the design seems to be the example of a camel being the product of a horse designed by a committee

• Instead of wanting a fast-climbing fighter with high-speed for destroying bombers, some wanted an aircraft able to mount extending patrols and carrying heavier firepower.
• For the escort-mission, they wanted long-range on internal fuel (they hated the idea of drop-tanks because they figure they'd be jettisoned at the start of combat), and a waist gunner (evidently the idea seemed to be for an airplane that could use it to augment the bombers defensive firepower, maneuvering only when necessary): I'm guessing the fighter & bomber guys were still butting heads like nobody's business because up to this point, fighter pilots generally had a dim view of this (the gunners were generally pinned under g-load and couldn't do anything).
• Some had taken a shining to dropping bombs on bomber formations (the USN actually had a similar idea for awhile), and this might have also fed into the idea of a fighter-bomber (or an attack-bomber variant).

 

[YGBSM]

It was a narrowly-won contest by the FM-1 - four-tenths of a point on a 100-point scale. The FM-2 was rated higher in some aspects to the FM-1, but the twin cannons of the FM-1 edged out the victory.

Bell won the competition by four-tenths of a point, 72 to 71.6, out of a possible 100 points. The clincher appearently was the big twin guns aboard the Airacuda. Lockheed's aircraft had two 1,000-horsepower Allison engines, as did the Airacuda, but it had only one cannon. Lockheed held the edge in engineering, but Bell scored 19.3 to 15.6 in military characteristics.

Source: Larry, a Biography of Lawrence D. Bell

The primary mission of the FM program was to intercept bombers - the idea being with the 37mm cannons to sit about 2 miles behind the enemy bomber formation and lob shells at will, well outside their defensive turret range. The Airacuda was doomed by its lackluster performance - it could barely outpace the bombers it was supposed to intercept, and it was expensive. By the time it was all said and done, and Airacuda was about twice the price of a B-17 at the time (I'm assuming a "D" model).

The design inspiration for the Neptune can be seen. Good find on the photos.

 

[Zipper730]

It was a narrowly-won contest by the FM-1 - four-tenths of a point on a 100-point scale.

That is close...

Lockheed held the edge in engineering, but Bell scored 19.3 to 15.6 in military characteristics.

So military characteristics means the planes ability to be used as a weapons platform, engineering means it was better designed and more rugged?

The primary mission of the FM program was to intercept bombers - the idea being with the 37mm cannons to sit about 2 miles behind the enemy bomber formation and lob shells at will, well outside their defensive turret range.

Was the traversable gun a requirement on either design or was that simply a choice on behalf of Bell?

 

[YGBSM]

I'm going out on a limb here because information regarding Army Air Corps acquisitions processes at the time is a bit sparse. I believe "military characteristics" is an evaluation of the prototype's ability to meet the performance specifications in the design requirements - speed, range, load, etc. Engineering as you said is probably a catch-all for overall design innovation and functionality.

I haven't seen any of the specific requirements other than the general call for a multi-seat heavy fighter. They are probably buried with the original documentation in an archive somewhere, or we haven't looked hard enough. It is a rather obscure corner of history we're delving into, so the documentation probably hasn't been digitized by anyone yet.

I've also seen mention of the fact that the official procurement procedures of the Army Air Corps were not always (or rarely) followed to the letter... so the reality of specific programs differed from what may be found regarding the procedures.

 

[vikingBerserker]

You're right. I can't find any designation for the circular proposal, but the idea appears to have been started by a letter written in early 1935 by Captain Harry A. Johnson to Major General Benjamin Foulis recommending a heavily-armed super fighter capable of destroying bombers. The new plane would have the new designation "FM" for "fighter, multi-place".

It actually started several years before that in 1933. On January 9th, 1933, a directive for a multi-seat fighter was submitted to the Pursuit Board at Wright Field and on March 22nd 1933, the Material Division at Wright Field issued Engineering Section Memorandum Report B-51-104 entitled "Modification of Martin B-10 Airplane To A Multi-Seat Fighter. One of the proposals was to have mounted forward firing machine guns and a retractable turret located below the fuselage. There would also be numerous gun ports/mounts where the gunners could move and remount the machine guns and was to carry 10 x 15lb bombs.

The modifications turned out to make the aircraft slower than the bombers it was to target and it was decided to go with a purposely designed aircraft. This led to the aircraft you mention.

 

[jmcalli2]

It was a different era, and dreams of designers were not realistic as these fanciful covers of magazines of the time show.

View attachment 493933 View attachment 493961 View attachment 493934 View attachment 493935 View attachment 493936 View attachment 493938 View attachment 493944 View attachment 493940 View attachment 493941 View attachment 493942 View attachment 493943View attachment 493962

Love those magazine covers!

 

[Gnomey]

Nice shots!

 

[Capt. Vick]

Great info. I never knew there was a competition and Bell actually won.

 

[Zipper730]

It actually started several years before that in 1933. On January 9th, 1933, a directive for a multi-seat fighter was submitted to the Pursuit Board at Wright Field and on March 22nd 1933, the Material Division at Wright Field issued Engineering Section Memorandum Report B-51-104 entitled "Modification of Martin B-10 Airplane To A Multi-Seat Fighter.

They probably picked the Martin B-10 because it was faster than the operational fighters of the time. Still, the idea of an aerial-defense gunship is kind of a flawed idea unless perhaps you have lasers (YAL-1).

 

[Zipper730]

The aircraft, IIRC was able to carry 600 pounds of 30 x 20 pound bombs that could be dropped on enemy bomber formations or people on the ground.

I'm curious where the bay was located

 

[johnbr]

643 Test 73 - XFM-1 (First setup) - NasaCRgis

 

[johnbr]

 

[johnbr]

643 Test 75 - XFM-1 (Second setup) - NasaCRgis

 

[johnbr]

Bell YFM-1 model

 

[Zipper730]

The thermionic director was mounted in the nose. It's optic looks like a light centered in the nose window.

I'm not sure if this was touched upon before, but how did it work? Was it a lead-computation device, or did it somehow work by identifying light contrast (i.e. aircraft block out light presenting a dark spot), or some mix of both?

 

[Zipper730]

So, to understand the chronology of things here basically

• 3/22/33: Directive was submitted to the Pursuit Board at Wright Field to modify the Martin B-10 to a multi-seat fighter. Proposals included forward firing machine guns, and a retractible turret below the fuselage; there were also various mounts where the guns could be re-located within the "fighter's" fuselage. 10 x 15 pound bombs were to be carried to drop on bomber formations.
• 1934: There were war-games/combat-exercises carried out during this period. I'm not sure the exact details, but some included attempting to intercept bombers. For some reason, some people decided that the solution was not more speed, but heavier firepower that could be lobbed outside the defensive range of enemy bombers.
• Early 1935: Captain Harry A. Johnson submitted a proposal to Major General Benjamin Foulois recommending a heavily armed super-fighter capable of destroying bombers. Bell & Lockeed were given $25000 to develop preliminary designs with a deadline of 3/15/36

I'm not sure when Bell wanted to get in on the fighter-aircraft business, but Bell was founded in July 1935 (so that could be the timeframe), and from 1928-1935 he worked for Consolidated, and when Consolidated moved to California, he stayed behind and set-up his own company.

I'm also not sure why the war-games exercises in 1934 lead to the conclusions that they did.

 

[johnbr]

net

 

[johnbr]