Monthly Archives: January 2015

N3N Record Setting – How is the “N” unique?

Three features of N3N history are commonly cited as record-setting:
1. The only aircraft that was both designed and built by the US Government
2. The last biplane in US Military Service (1960)
3. The longest serving biplane in US Military Service, 1935 – 1960 (25 years)

3022 NASM

But the BT-13 post below got me thinking about the survival rate of the N3N. The high survival rate is due to a combination of stout airframe (built like a bridge…) and commercial success, with some dusters working into the 1980s.

Only 816 N3N-3 aircraft were built. The FAA has 170-some registrations (it varies – I got 173 last time I run the list) and at least 6 are registered in other countries. So we have about 180 registrations, or some 22% of total production currently registered.

Does any other WWII era aircraft in volume production come close to a 22% survival rate? For this discussion lets set the “volume production” minimum as 100 units produced – to exclude limited production prototypes (i.e. 3 prototypes built, 1 survives – a 33% survival rate). For the BT-13 to match the N3N-3 percentage there would need to be over 2000 registrations. Or how about 3400 T-6/SNJ/Harvard registrations?

Any other Record-Setting features of our favorite aircraft?
– Is it the only fabric covered, all aluminum aircraft (most fabric aircraft have welded-tube steel fuselage)?
– Is it the first all-aluminum structure primary trainer for the US military?
– Is it the only convertible Land/Sea primary trainer ever produced? (The OJ-1 was a fleet aircraft, not a trainer)

Please chime in with any thoughts and comments…


My Birthday Present – and the BT-13

My brother gave me a Commemorative Air Force calendar for my birthday. I flipped through the year to see what aircraft were included. How about this aircraft – a BT-13 – for July:


For those of you who don’t familiar with the story, the postwar history of the BT-13 and the N3N are interwoven in an interesting way.

Surplus military aircraft were very cheap after World War II. A few hundred dollars could get you an aircraft. But what to do with them? Some aircraft were easily repurposed, such as the N3N which made a capable (and durable) agricultural aircraft. Others – such as the BT-13 – were almost useless. This is not to imply that there was anything wrong with the aircraft, just that no one could figure out a profitable civilian use for the aircraft.

As it turns out, the N3N had two weaknesses as an “ag” aircraft: The Bendix wheels / Lockheed brakes were not up to the job and the Wright J6-7 engine with only 235 horsepower limited the payload. The BT-13 had disc brakes and a Pratt and Whitney R-985 (at 450 hp). So a lot of surplus BT-13 aircraft were flown out to the desert, stripped of their engines, wheels/brakes/tires and rudder pedals and just left there.

Here is an accurately restored N3N showing off the original 30 x 5 wheels and Wright engine:

N3N-3 Taxi Test

Here is the “business end” of an N3N ag aircraft with the BT-13 wheels and P&W engine:

N45159 2994

If you go through the agricultural photo page here you will see that there are no photos of ag aircraft using the Bendix wheels. A few early dusters are shown with the Wright engine, but those are infrequent  (and I suspect all are before the end of the war).

A big reason why such a large percentage of N3Ns survive today is that they were profitable aircraft for decades. The BT-13 is a rare aircraft today even though over 9500 were built. So the high survival rate of the N3N fleet owes a debt to the BT-13 for the sacrifice that made the “N” the commercial success that is was.