Warbird Information Exchange

I was under the impression that about 1948 or so, after the Caroline Mars was built with P&W 4360's, that Martin was so impressed with the performance improvement over the Wright R-3350's that he converted all the remaining aircraft to 4360's.

Did Flying Tankers / Forest Industries convert them back to 3350's?

Walt

Does anyone know when they are to announce the plans for the planes?

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Chris Henry
EAA Aviation Museum Manager

Walt - as I understand it, only one Mars, the original JRM-2 was built with P&W R-4360s - all of the other Mars aircraft always had only R-3350s. All of the 4 surviving JRM Mars aircraft operated by the Navy from 1950-56 were equipped with upgraded 3,000 HP R-3350s and these were the same engines used on all of the firebomber airplanes including the existing two surviving aircraft.


Jim C.

This is the big question we are waiting to hear about. From the stories we have been able to uncover - many listed in this thread - no word yet on when final decision will be made or announced (but hopefully soon!)

Jim C.

From the Glen L. Martin Maryland Aviation Museum Mars webpage:

[quote]The Navy did purchase its sixth and last Mars with Wasp Major engines, which enabled the single JRM-2 to carry an extra 18,000 pounds of cargo on the San Francisco-to-Hawaii run. The four earlier planes were eventually re-engined with Wasp Majors as well and designated JRM-3's. All five served in the Pacific, carrying military personnel, Korean-war wounded, blood plasma, and other priority cargo over the same routes as were once flown by the glamorous clippers. Like them, they were duly christened for Pacific destinations: Philippine, Marianas, Marshall, a second Hawaii, and Caroline.

I've seen this info several places.

Walt

Walt - I looked at the Glenn L. Martin Aviation Museum website and you are exactly right about its references to the Mars a/c being re-engined to R-4360 Wasp Majors. However, I still believe that the actual engines on the final 4 Mars a/c were Wright R-3350s: look at the following internet link and scroll down to the later Mars references. It indicates that the JRM-2 "Caroline Mars" was the only Mars equipped with the R-4360s. It states that it and the other Mars survivors were all apparently upgraded to what is referred to as the "JRM-3" standard which included being re-engined with 3,000 HP R-3350s.

http://www.vectorsite.net/avmars.html

Also, in the recent book ''R-4360 Pratt & Whitney's Major Miracle" by Graham White published by Specialty Press in 2006 on Page 337 the sole Martin JRM-2 "Caroline Mars" is described as the only Mars equipped with R-4360s and says it was later re-engined to R-3350s for compatibility with the other Mars aircraft.

I agree that this has been a confusing issue, and I was unsure about this for awhile. I believe that the references on the Martin Museum website are just honest mistakes.

I think that the 3,500 HP R-4360s such as used on the C-97 series of aircraft would have been terrific engines for the Mars.


Jim C.