The Wright R-3350-57AM engines have been exchanged for a custom built combination of the R-3350-95W and R-3350-26WD engines. Wright Cyclone R-3350 2,200 hp each engine used to power the B-29 Superfortress. FIFI the only flying example of a B-29 Superfortress belongs to CAF.
FiFi engine update
This might be of interest to some of you. FiFi has had engine problems and the CAF has come up with a novel solution to replace them.
"For those of you interested in some further details about what we have planned for FIFI's re-engine project, I offer the following...
As with most projects that so many people have an interest in, there have been some welcome questions regarding what we have planned and why we chose the engines we have, where they came from, what they were on, how old they are, etc. We will be utilizing parts from the R-3350-95W and the R-3350-26WD engines in order to make our own engine for the B-29. Perhaps we should call it the R-3350-B29. One of the things I find interesting about this business is that we are able to make great airplanes even better. This requires some ingenuity and exploration. Sometimes plans work without a hitch, other times there are problems that have to be worked out. It's this reason that I must say that although we are very happy with our current plans, we are also very interested in hearing input from others that may bring up an issue we haven't foreseen. We are prepared to make whatever small adjustments we need in order to make this project a safe and reliable one.
The reason we chose the -95W engines are because we have them. In fact, we already have nine of them. They are a late (1965 or so) manufactured engine that went on AC-119K Gunships (attack version of the Boxcar). These are turbo-compound engines that are very similar to the DC-7 engine and were rated at 3,500 horsepower. We obviously cannot use the turbo compound portion of these engines, as they simply would not fit in the B-29 cowlings & nacelles.
This is where the -26WD engine comes in. This engine is what was used on the Douglas Skyraider. This particular dash number was manufactured from the early 1960's until the early to mid 1970's (depending on what information you read). These were EXCELLENT engines, just ask any Skyraider pilot or Sea Fury racer at Reno. The reason we need them is because the power section, blower section, and accessory section will simply bolt right up to our existing B-29 engine mounts. This will save us tremendous amounts of time since we won't have to design, test, and manufacture new engine mounts.
We plan on using the "guts," cylinders, and nosecase of the -95W in the "block" of the -26WD so that we can fabricate a strong and reliable engine with the least amount of work and money. We have no intention of trying to use the full 3500 horsepower of the -95W engine, as the B-29 airframe simply was not designed to take that kind of power. In addition, we intend on using the stock B-29 propellers, so we could not turn this "new" engine of ours up high enough to get that horsepower anyway.
Our estimates show the following:
Takeoff setting: 2,400 rpm and 44" of manifold pressure (roughly 2,400 h.p.)
Cruise setting: 2,000 rpm and 30" of manifold pressure. This is the same power setting that we use now and the same setting that the engine builders recommend for cruise flight. This should allow for the engines to be operated in a "normal" capacity, while still allowing more horsepower across the board. This is obviously an important figure when figuring the safety of flight if we were to lose an engine.
Since our takeoff power is merely the normal METO power of the -95W engine, we could (in theory) fly at that power setting for sustained periods of time. Again, not a bad thing to have if we were not flying on all four engines...plenty of "reserve power."
We will more than likely also see an increase in cruising speed for lower altitudes. At 30"/2000rpm the props will be turning faster than our old cruising prop speeds. FIFI will definitely have a different (more powerful) sound as well. Higher blower ratios should give us better cruising altitude capabilities too, if needed. We may have to clip the wings on Diamond LIL so she can keep up (grin).
Our first plan of attack is to build up a mock up that will include the external parts of our proposed engine, installed in a B-29 nacelle and cowling. Jeff Abbott is building up this "dummy" engine, while Kermit Weeks was kind enough to allow us to borrow the nacelle and cowling to save us time. Nelson Ezell will be working with this mock up to start with the fabrication of a new exhaust system and cowling modifications.
I could go on and on about this engine combination and if you'd like some more info on it, I'd be happy to get into more detail. As always, we very much appreciate any input you or any of our Squadron members or Warbird buffs might have. We have not thought of everything, but I can assure you, we have been thinking of everything we can.
Crew Chief, B-29/B-24 Squadron
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