Would B-29s have been better with R-2800s?
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Would B-29s have been better with R-2800s?
Ignoring for the moment the fact that it probably simply wasn't possible to build that many R-2800s for as many U. S. airplanes that needed them, and that it's never a good idea to rely on a sole-source engine supplier, would the trouble-plagued Boeing B-29 have been a more successful (i.e. more reliable) airplane if it had Pratt R-2800 engines?
Certainly the Wright R-3350 seems to have been plagued by near-intractable reduction-gear and engine-cooling problems right from the outset of its development, while the R-2800 ended up as reliable, and as pound-for-pound powerful, as a big-block Chevy Rat Motor...
Opinions?
Certainly the Wright R-3350 seems to have been plagued by near-intractable reduction-gear and engine-cooling problems right from the outset of its development, while the R-2800 ended up as reliable, and as pound-for-pound powerful, as a big-block Chevy Rat Motor...
Opinions?
I think the B29 would have needed at least six R2800 to replace four R3350. As soon as time allowed the R3350 was of course replaced by the P&W R4360.
Reduction gear design and manufacture, mixture distribution, cooling fin design, crankcase design, and, unbelievably, a cowling that could not be removed to allow engine maintenance without first removing the propeller.
There is some first class discussion of the many difficulties with this engine and some with the R2800 in the AEHS journal: see AEHS Home
(Look in particular for the articles by Kevin Cameron on the R3350s failings)
Reduction gear design and manufacture, mixture distribution, cooling fin design, crankcase design, and, unbelievably, a cowling that could not be removed to allow engine maintenance without first removing the propeller.
There is some first class discussion of the many difficulties with this engine and some with the R2800 in the AEHS journal: see AEHS Home
(Look in particular for the articles by Kevin Cameron on the R3350s failings)
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Thank you, Rory--excellent resource. Just joined the AEHS and I'm sure will make good use of it for an article on B-29 problems that I'm doing for Aviation History Magazine. Appreciate your help!
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Let me ask, before printing something stupid: are we all convinced that Rory57 is correct in posting, above, that the B-29's cowl "could not be removed to allow engine maintenance without first removing the propeller"?
I'm looking at a B-29 photo, a general shot and not a nacelle closeup, that seems to me to show enough Dzus fasteners to remove the forwardmost cowling section, and certainly the panels aft of that.
But I could be totally wrong. Anybody know better?
I'm looking at a B-29 photo, a general shot and not a nacelle closeup, that seems to me to show enough Dzus fasteners to remove the forwardmost cowling section, and certainly the panels aft of that.
But I could be totally wrong. Anybody know better?
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stepwilk, don't be so quick to give the 3350 a bad wrap. Certainly had issues to start with, as did the 2800, but matured into a dependable form of motive power. The expediency of war time had it rushed into service on an aircraft that was itself a technological leap forward. Never put a new engine in a new airframe used to be the addage. That the engine lasted 100 hours in the demands made upon it getting a fully loaded 29 to altitude and doing it following a take off on a diet of coral dust in the tropical heat gets applause from this quarter.
The prop didn't have to be removed. Would have made it difficult to carry out the interminable maintenance that needed to be done - plug changes (following every flight at times), wrenching up dripping oil connections etc. A good film doco of Daryl Greenmeyers attempted 29 (Kee Bird) recovery from Greenland is available out there which gives a good insight into engine maintenance, cowling removal etc
The prop didn't have to be removed. Would have made it difficult to carry out the interminable maintenance that needed to be done - plug changes (following every flight at times), wrenching up dripping oil connections etc. A good film doco of Daryl Greenmeyers attempted 29 (Kee Bird) recovery from Greenland is available out there which gives a good insight into engine maintenance, cowling removal etc
On the early B-29/R-3350 installations the prop did have to be removed to get the cowling off. This was later modified, which is why the fasteners are visible on most photos. I haven't got a reference handy for this right now but will try to look it up.
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In August of 1939, Boeing had started work on the Model 341 project, which featured a new high-lift aerofoil for a high aspect-ratio wing of 124 feet 7 inches in span. The Model 341 offered a maximum speed of 405 mph at 25,000 feet. It was to have been powered by four 2000 hp Pratt & Whitney R-2800 radials. Weighing 85,672 pounds, the range was to have been 7000 miles with one ton of bombs. A maximum load of 10,000 pounds could be carried over shorter distances. The design was subsequently reworked to become the Boeing Model 345 aka B-29.
Boeing XB-29 Superfortress
Boeing XB-29 Superfortress
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B-29 cowling
Having spent many hours pulling on and off the cowling of the B-29 Kee Bird, I can assure you that the propeller was indeed in place. Granted, this was a later model B-29 known as the F-13. By my experience, I can not even IMAGINE that there was ever a version that required pulling the prop first. Those engines needed way too much tender loving care. Needing to pull the prop just to change spark plugs is just totally illogical in my limited experience.
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FunkyStick, you may be "new here," but you're sure a player. What an epic you were part of, sad as it turned out. You have my admiration.
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A big 
Funky. The video is a treasured possession and the ending certainly came out of left field. Enough to make a grown man cry, particularly given the effort and deprivation suffered. And that's not to mention the death of a hard toiling colleague.
Funky. The video is a treasured possession and the ending certainly came out of left field. Enough to make a grown man cry, particularly given the effort and deprivation suffered. And that's not to mention the death of a hard toiling colleague.
Still looking for original evidence of my assertion about B29 propeller removal for maintenance. Bill Gunston refers to it briefly in Piston Aero Engines but I know I have read something at length about it, referring to the first deployment. (India / China?) Meanwhile, have a look at this superb set of B29 photos on Flickr.
B-29 Superfortress - a set on Flickr
B-29 Superfortress - a set on Flickr
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FunkyStick, the DVD of the Kee Bird saga is one of the best and, sadly, one of the most poignant films I've ever seen. I really wish that Darryl had pulled it off... And as Brian says, would that Rick was still with us. He came across as a really nice bloke.
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Rory, be very interested in a source for your prop removal assertion. Can find no mention anywhere. The 29 AFM includes an item about turning the prop by hand to check for hydraulic lock during the pre flight, and details the procedure for determining which is the offending cylinder, then removing the spark plugs on that cylinder, draining the oil and installing new plugs. It notes this check should be made early in the pre flight, and remedial action taken should a lock be found, so that the scheduled take off time can be met. To my way of thinking, if it was necessary to remove the prop there is no way that a lock could be fixed in short order. I suspect it may be a myth, perhaps generated by the fact that the props were the last thing to be fitted on the production line.
Brian, I'll have a go tonight at finding a reference for that. I'm sure I've read it in more than one place but all my books are stored in boxes in the basement. That doesn't speed up the search unfortunately.
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Pulling spark plugs on the engine
<<To my way of thinking, if it was necessary to remove the prop there is no way that a lock could be fixed in short order. I suspect it may be a myth, perhaps generated by the fact that the props were the last thing to be fitted on the production line.>>
It was SOP to pull those props thru by hand when we were in Greenland. It was pretty routine to have a pull a spark plug for any engine start. And no props came off.
It amazes me to this day just how much interest this project created. For years I had non-aviation people tell me that 'I just wanted to cry at the end' of the program. The show did a good job of telling the story, but so much never made it to air for a variety of reasons.
By the way, I was a NOT a mechanic. I became an assistant to the assistant to the lead mechanic. I did the kind of jobs that didnt take brains or knowledge. It was an amazing experience that I"m glad I lived through but I'm not sure I would do it again. We were very lucky in many ways.
It was SOP to pull those props thru by hand when we were in Greenland. It was pretty routine to have a pull a spark plug for any engine start. And no props came off.
It amazes me to this day just how much interest this project created. For years I had non-aviation people tell me that 'I just wanted to cry at the end' of the program. The show did a good job of telling the story, but so much never made it to air for a variety of reasons.
By the way, I was a NOT a mechanic. I became an assistant to the assistant to the lead mechanic. I did the kind of jobs that didnt take brains or knowledge. It was an amazing experience that I"m glad I lived through but I'm not sure I would do it again. We were very lucky in many ways.
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R-3350s were particularly susceptible to the lowest-cylinder oil leakage that created hydraulic lock. Certainly R-2800s weren't routinely pulled through on P-47s and all the rest of the airplanes that carried them.
And as you of all people doubtless know, an eight-foot-long prop blade can actually provide enough leverage that two guys pushing too hard on it can bend a rod. You don't even have to start the engine.
And as you of all people doubtless know, an eight-foot-long prop blade can actually provide enough leverage that two guys pushing too hard on it can bend a rod. You don't even have to start the engine.
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Rick
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<<He came across as a really nice bloke.>>
I didnt "fit in" the group when I first arrived. I was a journalist, an environmentalist, not "a wrench" and not the TV crew. I was, to a lot of folks, deadweight. But when I returned to the Kee Bird from Thule, after passing up the opportunity to return home early, Rick made a point to tell me he was glad I was back. It was one of my favorite moments of the entire experience. Rick, to me, was an artist with a wrench. He amazed me time and again with his ability to solve problems and he never, ever, raised his voiced at anybody. Gaining his respect and appreciation was one of the best things that happened to me.
When the Kee Bird burned, I didnt shed a tear. When Rick was taken away on that stretcher, I put down my cameras and Cecilio (my "boss" and Rick's assistant) and I stood at the nose of the Caribou and we cried unashamedly.
Rick is, and always will be, the real tragedy of the Kee Bird.
<<He came across as a really nice bloke.>>
I didnt "fit in" the group when I first arrived. I was a journalist, an environmentalist, not "a wrench" and not the TV crew. I was, to a lot of folks, deadweight. But when I returned to the Kee Bird from Thule, after passing up the opportunity to return home early, Rick made a point to tell me he was glad I was back. It was one of my favorite moments of the entire experience. Rick, to me, was an artist with a wrench. He amazed me time and again with his ability to solve problems and he never, ever, raised his voiced at anybody. Gaining his respect and appreciation was one of the best things that happened to me.
When the Kee Bird burned, I didnt shed a tear. When Rick was taken away on that stretcher, I put down my cameras and Cecilio (my "boss" and Rick's assistant) and I stood at the nose of the Caribou and we cried unashamedly.
Rick is, and always will be, the real tragedy of the Kee Bird.