by Tommy H. Thomason

Wednesday, September 30, 2015

Modeling the Bell XFL-1 Airabonita

The Bell XFL-1 Airabonita was a one-off prototype based on Bell's P-39 that competed with the Vought XF4U-1 and the Grumman XF5F-1 following the U.S. Navy's 1938 carrier-based fighter competition.

It looks like it would be a colorful and straightforward conversion of the P-39, kits of which are available in every popular scale from 1/144 to 1/32. In fact, several have been done and documented in articles in modeling magazines. However, most—if not all—fall short of representing the actual XFL-1 configuration. Unfortunately, most of the structure, particularly the canopy, was different in detail from the P-39. Not even the 1/72 XFL-1 kits that are available are accurate, since they have the P-39 wing planform, which was somewhat different in taper and span.

(Note that the XFL-1 wing root is also closer to the fuselage centerline than the P-39's.)

 For example, this is what it takes to convert a P-39 wing to an XFL-1 wing:

Another, more notable difference was the canopy and door, since over-the-nose visibility was critical for a carrier-based airplane.

All this and more is contained in my XFL-1 monograph, available from Steve Ginter:

In addition to most of the photographs extant of the XFL-1, there are illustrations of the configuration changes during development like the empennage. Since the Navy specifically included the XFL-1 in the competition to evaluate the performance benefit of the new 1,000-hp Allison liquid-cooled engine,  it includes a summary of the history of aero-engine development, comparing and contrasting the benefits and shortcomings of the liquid-cooled versus air-cooled engine. It also places the XFL-1 in the context of the Navy's rapid transition to monoplanes and new requirements like armor and self-sealing fuel tanks.

Even if you don't need a model of an XFL-1, the monograph provides interesting background on aero engine and Navy airplane development between the World Wars.

1 comment:

  1. The XFL may have lost to the F4U, but it shows that Bell could make a Cobra with a tailwheel for a short take-0ff, and carry fuel for a longer combat radius. Just these 2 flaws made the P-39 a logistical headache. The larger wing addressed the Cobra's stall-turn handling, and spin was damped a bit by the taller tail. If only it kept the turbo of the XP-39! It was a Navy fighter. If it was free of the Army's rationing of turbos on their own fighters except P-38s, the XFL should have developed the B5 turbo with rare tungsten for reliability. So, without guns it had a top speed in 1940 of only 336 mph at 10,000' and 307 mph at s.l. Climb to 20,000' took 9.2 minutes - about the same as the faster P-39D with guns. At least the XFL had a supercharger like the P-39s. The P-400 Cobra didn't. So it took 15 minutes to climb 20,000'. The Cobra could have been better due to the Bell XFL fighter.