Warbird Information Exchange

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.

Regards,
Gary Austin
Crew Chief, B-29/B-24 Squadron
Commemorative Air Force

Gary;
Good luck with this, I sure would like to see FIFI fly again. I have few questions for you. Will these engines be zero timed or overhauled per say? Also what kind of paper work are you looking at, in dealing with the Fed’s? Or do you have to worry about that stuff on a (I assume) Restricted category airplane?
Scott.......

Thanks for the update Gary. Very impressive game plan you hve there. Hope everything works out.
Robbie

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Fly Fast Make Noise!

Gary,

As a 3350-26WD operator (EA-1E) I have become convinced that the reliabilty factor associated with the skyraider powertrain is in part due to the combination of the engine and the pairing with the Aeroproducts prop. The self contained (doesn't use engine oil) nature of the prop adds to the reliabilty because activation/movement of the prop doesn't scavage oil off the front bearings in the engine etc.

Obviously, a few other props are in use with this engine, I guess my question is - Are there any good stats regarding reliabilty/longevity of the 3350-26WD when using a prop other than the Aeroproducts? I guess the Sea Fury group would be the best control group to look at, and Jeff Abbott and Nelson would have the best insight.

Just curious, best of luck and keep up the good work.

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Eric

"I spent most of my money on alcohol, women and skyraiders....and the rest of it I just wasted."

Eric,
That is an excellent question! As a mechanic, I love the Aeroproducts propeller. It is a cinch to work on and although I've never really put any thought into the point you've made about the oil issue, I would imagine that there might be some truth to it.
However, since we are running the big Hamilton Standard props on this airplane, we will rely on our engine pre oilers to get those front bearings all lubed up before we start the engines. The electric pre oil system is, in my opinion, one of the best things that anyone can put on his big round engine to assist with longevity.
As far as the Sea Fury guys and their prop installations vs. reliability, that would be a very interesting study. Although, with my experience in the Sea Fury world, I can't say that I've seen a difference. But I will always like the Aeroproducts prop over the Ham Standard though.

Gary

As far as the prop oil issue, you could ask the Neptune operators, as they are swinging a big Ham-Standard out front.
Scott....

I think I'm speaking for a lot of folks when I say good luck, I hope it all works, and we can't wait to see FiFi back in the skies once again....it sounds like a good game plan and with Nelson helping you guys out I think it will be a winner.

Mark

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Mark Morris