R-2600 + turbo: was that ever a viable thing?

[tomo pauk]

One of the rare major US engines that was never used in a turbocharged form (not counting prototype installations, like the one tried at A-20). Was the turbo R-2600 ever a viable possibility, or the engine 'defied' in some way against a turbo?

[Shortround6]

I don't know. I have seen a few comments about it but nothing to back them up. I don't know of any other tries except the A-20 ( doesn't mean that they didn't exist, just not well recorded?) Why they weren't used on the P-70 night fighter is a puzzle.

[rinkol]

Possibly there were teething problems that could have been solved, but did not have sufficient priority. Most of the R-2600 applications did not make any special demands on high altitude performance and it would have made sense to concentrate on larger engines, specifically the R-2800 and R-3350; these had important applications where high altitude performance was critical e.g., P-47 and B-29.

The early turbosupercharger installations did have some control and reliability issues; for example some installations were known to have problems with surging (the Hercules VIII seems to have been one such case).

[tomo pauk]

Thanks for the inputs

Would it be right to conclude that there was nothing special that would hamper the R-2600 + turbo in a plane?

[Shortround6]

We don't really know, there are reports with no details that the A-20 with turbos had trouble. There was also a change in policy about what altitude the light/ medium bombers would operate at that meant they didn't need turbos.

Turbos were planned for the 4 engine version of the Martin B-33 ( 400 planes ordered but all canceled before the prototype was even started)

In theory there is nothing to prevent it but in practice things don't always work out. The Theory was that the turbo would hold the exhaust back pressure to the same value as a non-turbo plane at sea level. In practice the back pressure was always several lbs higher until well above the critical altitude. This MAY have caused problems with cooling the exhaust valve and exhaust port area of the cylinder head.

[gjs238]

There was also a change in policy about what altitude the light/ medium bombers would operate at that meant they didn't need turbos.

SR: Could you elaborate on this policy? Just curious.