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So
5th R-3350-BA accepted October 1939
5th R-2800-A accepted March 1940
5th R-2800-C accepted August 1943
5th R-3350-BB accepted December 1943
Are '5th engines' production engines?
Both the C and BB series look a long way too late for service testing but the BB would be easier to retrofit, with a Wright powerplant already in place
1937. R-3350 engine first run.I'd rather use the R2800 than the R3350. those engines were prone to failure
The problem with the intakes was the difference in the throw between the front cylinders and the rear bank and the inherent difference this inferred on mass airflow. This was solved when the Bendix (or Chandler Evans, in some cases) carburation was replaced with Bendix Stromberg injection units (two per powerplant, one feeding each bank) at 500psi injection pressure.I heard the problem with the 3350 was the ridiculously long intakes, it would lean out cylinders on the early versions till fuel injection.
Curtiss-Wright also was not a good trouble-shooting company. They would just thow bigger parts at it and not really fix the problems, just mask them. I do admire the turbo compound versions, probably one of the most efficient piston engines ever made, a little too late. The company never really recovered from bad judgement and trouble-shooting
My sourcesAs far as I know the original concept for the "B-29" (Model 341 project) by Boeing was originally designed to be powered by 4 R-2800s. The P&W's were only dropped by Boeing in favor of the R-3350's when the AAF released the Very Long Range Bomber spec R-40B which suggests they adopted this engine to meet the more steep demands of this spec's requirements
There were some fundemental differences between the development of the R2800 and R3350. The R2800 used traditional metals and was just an increase in size as compared to existing designs.
The R3350 used magnesium alloys in a far smaller frontal area. This is what gave problems and issues during the development of the engine, and why it took so long to get the "bugs" worked out of it.
From what I can gatherThere were some fundamental differences between the development of the R-2800 and R-3350. The R-2800 used traditional metals and was just an increase in size as compared to existing designs
It was in fact the R-2800 that used magnesium in its construction, the reduction gearing, magneto drive, distributor drive, propeller governor drive and scavenge pump were housed in a single-piece magnesium casing.The R3350 used magnesium alloys
This is what gave problems and issues during the development of the engine, and why it took so long to get the "bugs" worked out of it.