Hypothetical Curtiss P-36N — A P-40N Returning to Radial Power

[Jugman]

I have it with an R1830-SSC7-G engine making 389mph @ 19,000 ft.

My source is Dean & Hagedorn. I reread the five paragraphs they have about it. The initial top speed was 380mph at 24,000ft. P&W expected this speed to drop to 370mpg fully combat loaded. Layer this improved to 388 @ 25,000ft. Looking around I have seen 389 @ 22,700ft too. None of these figures really contradict each. I think 25,000ft is a little high for a two-stage R-1830 but the engines my not have been stock.

 

[BobB]

A P-36 updated to have the R-1820 used in the FM-2 would have been adequate for a lot of jobs but why run a production line for an adequate fighter instead of building more P-47, P-51, F6F, F4U, etc? A P-36 with the 1425/1525 hp engines used in T-28/S2F would be a neat toy to have today.

 

[GrauGeist]

A P-36 updated to have the R-1820 used in the FM-2 would have been adequate for a lot of jobs but why run a production line for an adequate fighter instead of building more P-47, P-51, F6F, F4U, etc? A P-36 with the 1425/1525 hp engines used in T-28/S2F would be a neat toy to have today.

The P-36 and the R-1820 predate the P-47, P-51, F6F, F4U.

At the time of the P-36's debut (with the R-1830), it was in a class with the Hurricane, Bf109 and the A5M.

 

[BobB]

The P-36 and the R-1820 predate the P-47, P-51, F6F, F4U.

At the time of the P-36's debut (with the R-1830), it was in a class with the Hurricane, Bf109 and the A5M.

Note the reference to "R-1820 used in the FM-2". The R-1820-56 was not in production until 1943. P-47, P-51, F6F & F4U predate the R-1820-56.

 

[Shortround6]

Problem with the 1425-1525hp engines today is that the fuel has gone away. They needed either 115/145 fuel or water injection with 100/130 fuel to hit those numbers.
Those numbers were only available at low altitudes, like 2000ft or less depending on fuel. 1425 was available a bit higher.
Still an interesting concept.

 

[GrauGeist]

Note the reference to "R-1820 used in the FM-2". The R-1820-56 was not in production until 1943. P-47, P-51, F6F & F4U predate the R-1820-56.

The P-36A was powered by the R-1830-17, rated at 1,200 hp, which happens to be the rated HP of the R-1820-56 - where are we going with this?

 

[BobB]

The P-36A was powered by the R-1830-17, rated at 1,200 hp, which happens to be the rated HP of the R-1820-56 - where are we going with this?

"The P-36 and the R-1820 predate the P-47, P-51, F6F, F4U."

"At the time of the P-36's debut (with the R-1830), it was in a class with the Hurricane, Bf109 and the A5M."

I wish that I knew where you thought you were going. I see that you revised your posts to clarify that the P-36's purchased on US Army contracts had R-1830's. The R-1820-56 (available in 1943) was rated 1350 hp on 100/130 octane fuel which gave a performance boost on the Wildcat and could have done the same on the P-36 but by 1943 even an improved P-36 would have been a waste of resources compared to concentrating on P-47, P-51, F6F, F4U.

 

[BobB]

Problem with the 1425-1525hp engines today is that the fuel has gone away. They needed either 115/145 fuel or water injection with 100/130 fuel to hit those numbers.
Those numbers were only available at low altitudes, like 2000ft or less depending on fuel. 1425 was available a bit higher.
Still an interesting concept.

I recall some mention that some Navy T-28's had 115/145 octane engines and were considered hot rods but I don't know what those engine differences were. The T-28D conversions used -56(1350 hp on 100/130),-76(1425hp on 100/130) or -80(1475 hp on 100/130) engines. Pacific Airmotive had a large stock of -56 engines which must have been WW2 surplus from FM-2's and Bill Lear hooked up with them to get engines for his Learstar conversions. North American also got involved with Pacific Airmotive when they came up with the notion to convert surplus T-28A's to R-1820's.

 

[Frog]

I recall some mention that some Navy T-28's had 115/145 octane engines and were considered hot rods but I don't know what those engine differences were. The T-28D conversions used -56(1350 hp on 100/130),-76(1425hp on 100/130) or -80(1475 hp on 100/130) engines. Pacific Airmotive had a large stock of -56 engines which must have been WW2 surplus from FM-2's and Bill Lear hooked up with them to get engines for his Learstar conversions. North American also got involved with Pacific Airmotive when they came up with the notion to convert surplus T-28A's to R-1820's.

The French Armée de l'Air contracted Sud-Aviation to switch the original Wright R-1300-7 Cyclone engines from 146 T-28A's with surplus Wright R-1820-97 Cyclone disassembled from condemned B-17s stockpiled in the USA.

they were also equipped with the same three blades propellers as used by the US Navy TJ-1 Trojan.

They replaced the T-6G Texan used for armed COIN warfare.

For administrative purpose, they were T-28F's for North American and T-28S's (S for Special) for the USAF. In France the were T-28 Fennec.

 

[BobB]

The French Armée de l'Air contracted Sud-Aviation to switch the original Wright R-1300-7 Cyclone engines from 146 T-28A's with surplus Wright R-1820-97 Cyclone disassembled from condemned B-17s stockpiled in the USA.

they were also equipped with the same three blades propellers as used by the US Navy TJ-1 Trojan.

They replaced the T-6G Texan used for armed COIN warfare.

For administrative purpose, they were T-28F's for North American and T-28S's (S for Special) for the USAF. In France the were T-28 Fennec.

North American came up with the mod and licensed it to France. Their prototype mod aircraft made a forced landing in New Mexico due to engine icing up. As the crew walked out to civilization, they passed the wreckage of Mike Todd's Learstar that had crashed a few years earlier.