XP-39 first flight date.

Seems pretty conclusive to me: contemporary reports indicate 1939 and only recent stuff is stating 1938.

I do wonder though who compiled that information on the site, was it a dedicated historian or just someone who needed a bit of copy? I have seen errors on other company websites in the past.

But this does further cloud the issue of the date.

According to Bell — LINK – http://www.bellhelicopter.com/company/history/1935-1949
It was 1938.

Thank you for taking the time to give a breakdown and you do make a very convincing argument Graham, plus the link to the document in 1941 supports this (thanks Beermat).

If you regard all sources of information as being equally reliable, you are going to find a large number of confusions wherever you look. Some works are much more thoroughly researched than others, and yes, perhaps you have to read them to distinguish between them. However, in his book Matthews gives a thorough account of the processes leading to the first flight, if falling somewhat short of a daily chronology which perhaps may convince you. The specification was not issued until March 1937. Submitted designs were not evaluated until 17-22nd August 1937. (Dates available in public records.) The contract to Bell was awarded on 7 October 1937. This does not leave enough time for an aircraft to be properly designed, built and flown, even had no further information been available. But it is. The XP-39 was ready for ground testing “by the end of 1938”. The engine was run for the first time on 4th December 1938. The source credited for this is Bell Aircraft Corporation Report 4Y021. It was then shipped to Wright Field where it arrived two days after Xmas. Three days assembly, four days inspection, 37 faults to be corrected, and it was ready for flight test in early February, with an engine run on 8th February followed by an engine return to Allison – no spare stack of V-1710s in 1938. An engine was returned, reinstalled, and running again in early April 1939. A 20 min first flight on 6th April 1939. The source for this is given as Bell Corporation log of activities at Wright Field. It includes references to the arrival of the P-38 prototype – was that also a year out in its dates?

Now if any of your other sources go into a similar amount of detail for an April 1938 flight, from equally reputable sources, then I’ll accept you’ve reason to be unsure of the correct date. Somehow I doubt it.

s/n is the Fiscal Year that the aircraft budget was approved: as a good example the prototype XP-86 had a 1945 s/n but flew in 1947.

This is from August 1941, so I doubt it is out by a whole year – ‘Early 1939’

http://docs.bell.lib.in.us/Originals/the%20story%20of%20the%20bell%20airacobra.pdf

The serial number gives the year when ordered…The Ray Wagner book of American Military Aircraft gives the first flight as April 1939

Were US serials allocated by date of first flight? Are you sure, Duggy?

The serial # should give you the answer 38-326
So it was April 1938.
Regards Duggy.

Thanks, I’ve had similar answers elsewhere so am still none the wiser on which year it is.

May 1939 issue of Aviation Week (page 55) carried a photo and indicated a first flight ‘last month’ at Wright Field.

The definitive book is probably Birch Matthew’s “Cobra” from Schiffer, and he quotes 6th April 1939 with much supporting detail in the surrounding chapter, which runs to 25 pages on this prototype

Alain Pelletier’s “Bell Aircraft since 1935”, which should be definitive, does say 1938 but this is in the middle of other comments that make it clearly an error. For example, that the aircraft was originally to be delivered by August 1938 and that by 6th June 1939 only some 60 flying hours had been logged.