HELP: Difference between 1930s US Navy Stearman NS-1 and Model 75 ?

[95B Rules]

I have photos from the late 1930s and I'm having trouble actually identifying the difference. Much appreciated

 

[Geoffrey Sinclair]

Unfortunately there seems very little external difference between the NS-1 and model 75, the NS-1 was probably a few inches longer as it mounted a larger displacement but still 9 cylinder engine. All I can do is give dates of when the military versions were built.

The Stearman model 70 won the Army primary Trainer Contest in 1934.

The USN ordered 61 as the NS-1/model 73, 1 accepted in December 1934 and another 60 between May 1935 and April 1936, Wright J-5/R-790-8 engine. The next USN order was for the N2S-1/PT-17, first of 250 acceptances in September 1940, also accepted were 125 N2S-2/PT-13A and 225 N2S-3/PT-17 in 1941 but post September 1941 all production was officially for the USAAF.

The USAAF PT-13/Model 75 had Lycoming R-680-5 engines, 26 accepted June to December 1936, then came 92 PT-13A, Lycoming R680-7 engine, accepted June 1937 to June 1938.

October 1939 saw the start of the PT-13B acceptances, Lycoming R-680-11 engine.

 

[95B Rules]

Unfortunately there seems very little external difference between the NS-1 and model 75, the NS-1 was probably a few inches longer as it mounted a larger displacement but still 9 cylinder engine. All I can do is give dates of when the military versions were built.

The Stearman model 70 won the Army primary Trainer Contest in 1934.

The USN ordered 61 as the NS-1/model 73, 1 accepted in December 1934 and another 60 between May 1935 and April 1936, Wright J-5/R-790-8 engine. The next USN order was for the N2S-1/PT-17, first of 250 acceptances in September 1940, also accepted were 125 N2S-2/PT-13A and 225 N2S-3/PT-17 in 1941 but post September 1941 all production was officially for the USAAF.

The USAAF PT-13/Model 75 had Lycoming R-680-5 engines, 26 accepted June to December 1936, then came 92 PT-13A, Lycoming R680-7 engine, accepted June 1937 to June 1938.

October 1939 saw the start of the PT-13B acceptances, Lycoming R-680-11 engine.

phew, alot packed in there. Much appreciated. I'll just call it NS-1 . I mean it is on the tail in photos, but in research always brings up Model 75 so was just wondering. Much appreciated

 

[Wurger]

Found at : Stearman 75 / 76 / 90 / 91 / PT-13 / PT-17 / NS-1 / N2S / PT-18

The Model 75 was powered by a 215 hp Lycoming and was designated by the military as the PT-13.
The series that was produced in the largest numbers was the Model A75NI. It was similar to the PT-13 but was powered by a 220 hp Continental radial engine; its military designation was PT-17. The Navy named the Boeing 75 the NS-1.

The first NS-1 for the Navy was the biplane s/n 9677 USN, c/n 73-0001.

the source: Stearman-Boeing NS-1 trainer by Hank Clark

 

[95B Rules]

Found at : Stearman 75 / 76 / 90 / 91 / PT-13 / PT-17 / NS-1 / N2S / PT-18


The first NS-1 for the Navy was the biplane s/n 9677 USN, c/n 73-0001.
View attachment 645616
the source: Stearman-Boeing NS-1 trainer by Hank Clark

go figure that the navy would call it something different than real name. Here is one of my photos. The 2nd one is number 9679 and closest is 9681

 

[Wurger]

Yes .. you are right. Contrary to the Army , the Navy used the different designation name. Also it was different from the Stearman/Boeing marking.
Judging by these serials in the pic you posted these are the first batch for the Navy. As the mate Geoffrey Sinclair has mentioned it above, the first 61 NS-1s were powered by the Wright J-5/R-790-8 Whirlwind engine.

 

[95B Rules]

Yes .. you are right. Contrary to the Army , the Navy used the different designation name. Also it was different from the Stearman/Boeing marking.
Judging by these serials in the pic you posted these are the first batch for the Navy. As the mate Geoffrey Sinclair has mentioned it above, the first 61 NS-1s were powered by the Wright J-5/R-790-8 Whirlwind engine.

Ya this photo album was from a cadet going through pensacola Naval Air Station '36 - '37 Some amazing photos.

 

[Wurger]

Additionally :

Factory name | Army name | Navy name | engine type

Stearman 73 ( actually Stearman 70 ) - Navy NS-1, engine Wright J-5/R-790-8 Whirlwind
Stearman 75 (from 1939 .. Boeing 75) - Army PT-13, engine Lycoming R-680-5
Steaman A75 - Army PT-13A, B, C, engine Lycoming R-680-7,11
Stearman A75NI - Army PT-17, Navy N2S-1 and N2S-4, engine Continental R-670-4
Boeing 75 - Navy N2S-2, engine Lycoming R-680-8
Boeing 75N1 - Navy N2S-3, engine Continental R-670-4
Boeing E75 - Army PT-13D and Navy N2S-5, engine Lycoming R-680-17

 

[Geoffrey Sinclair]

For comparison with the web site at

Stearman 75 / 76 / PT-13 / PT-17 / NS-1 / N2S / PT-18 / PT-27

all this about aviation, airplanes, helicopters,

all-aero.com

As noted I have no original documents on civil production, plus nothing on pre 1940 sales to foreign militaries and post 1945 production.

Data from Foreign sales from Report NO. WS-378 (From USAF Material Command Archives) Airplane and Glider Acceptances, Factory Deliveries and Departures from U.S. by type, model and country. Based on contracts active as of January 1940, excluding Navy direct, Navy Lend Lease and Commercial For period January 1940 to December 1942 inclusive. Prepared by Aircraft Delivery Unit, Statistical Control Office

A-73E-1, 3 for Cuba in March 1940. (CU-2983) (A-73 probably a typo)
A-75L-3, 20 for Brazil February to May 1940 (ZL-50-2887)
A-75L-3, 3 for Venezuela July 1940, another 4 in November 1941 (VZ-2996 and 3181)
A-75L-3, 12 for the Philippines May 1941 (PP-3061)

Total A-75L for Brazil, Philippines and Venezuela is 39, versus 43 on the web site.

A-75B-4, 5 for Venezuela November 1941 (VZ-3181)
A-76B-4, 5 for Venezuela November 1941 (VZ-3181)

PT-17, 18 for Peru January and February 1942 (PU-SO-4111, also counted below in PT-17 figures)

There were further acceptances for countries including Columbia and Bolivia but these were officially diversions from USAAF contracts.

To complete the wartime production numbers.

PT-13B 255 October 1939 to April 1941
PT-13D 895 plus 873 as N2S-2, June 1943 to February 1945
PT-17 2,960 May 1940 to June 1943, plus N2S-4/PT-17 455 June to November 1942 and 122 June and July 1943.
N2S-3/PT-17A 1,650 July 1942 to June 1943
PT-18 150 July 1940 to March 1941.
PT-27 300 for RCAF February to October 1942 with the note 299 were accepted to end July. (DA-1338) (25 diverted to USA, accepted February to May 1942)

All up total 7,830.

 

[macharvard]

For comparison with the web site at

Stearman 75 / 76 / PT-13 / PT-17 / NS-1 / N2S / PT-18 / PT-27

all this about aviation, airplanes, helicopters,

all-aero.com

As noted I have no original documents on civil production, plus nothing on pre 1940 sales to foreign militaries and post 1945 production.

Data from Foreign sales from Report NO. WS-378 (From USAF Material Command Archives) Airplane and Glider Acceptances, Factory Deliveries and Departures from U.S. by type, model and country. Based on contracts active as of January 1940, excluding Navy direct, Navy Lend Lease and Commercial For period January 1940 to December 1942 inclusive. Prepared by Aircraft Delivery Unit, Statistical Control Office

A-73E-1, 3 for Cuba in March 1940. (CU-2983) (A-73 probably a typo)
A-75L-3, 20 for Brazil February to May 1940 (ZL-50-2887)
A-75L-3, 3 for Venezuela July 1940, another 4 in November 1941 (VZ-2996 and 3181)
A-75L-3, 12 for the Philippines May 1941 (PP-3061)

Total A-75L for Brazil, Philippines and Venezuela is 39, versus 43 on the web site.

A-75B-4, 5 for Venezuela November 1941 (VZ-3181)
A-76B-4, 5 for Venezuela November 1941 (VZ-3181)

PT-17, 18 for Peru January and February 1942 (PU-SO-4111, also counted below in PT-17 figures)

There were further acceptances for countries including Columbia and Bolivia but these were officially diversions from USAAF contracts.

To complete the wartime production numbers.

PT-13B 255 October 1939 to April 1941
PT-13D 895 plus 873 as N2S-2, June 1943 to February 1945
PT-17 2,960 May 1940 to June 1943, plus N2S-4/PT-17 455 June to November 1942 and 122 June and July 1943.
N2S-3/PT-17A 1,650 July 1942 to June 1943
PT-18 150 July 1940 to March 1941.
PT-27 300 for RCAF February to October 1942 with the note 299 were accepted to end July. (DA-1338) (25 diverted to USA, accepted February to May 1942)

All up total 7,830.

Great thread, fellas. 70 years studying aviation history and I still don't know it all!

 

[MiTasol]

The NS-1 has a very different main landing gear from the later aircraft and there are two very different but otherwise visually "identical" landing gears (long and short) on the PT and N2S aircraft but I cannot remember if the difference was Army and Navy or engine related. (I must be getting old).