Official B-29 Doc Restoration Thread

[maxum96]

One of his B-29's is for sale http://www.aerotrader.net

That's been for sale for years.

[B-29 Watcher]

Well at least we have some B-29's (kermit's & FIFI) to talk about. We are not getting any thing from DOC, it was getting exciting, when Ryguy & Jeremy could talk & give some photos. It felt like we were in the loop, a part of something. Now, nothing, it feels like we were locked out. We Warbird followers are the ones who support these old birds at shows & through our donations. I would think we could be kept in the know especially in such a big project. Maybe they will allow more news if they know we care. I, for one, am very interested in the updates.

[Jeremy S]

They only occasionally post pictures to their Facebook page, and those are far and few in between. Still, they have posted more in the last few months than they did in the last 3 or 4 years!

Flight engineers station:



"Restoration volunteer Wanda Flynn working to restore the Flight Engineer station."

[menards]

Well at least we have some B-29's (kermit's & FIFI) to talk about. We are not getting any thing from DOC, it was getting exciting, when Ryguy & Jeremy could talk & give some photos. It felt like we were in the loop, a part of something. Now, nothing, it feels like we were locked out. We Warbird followers are the ones who support these old birds at shows & through our donations. I would think we could be kept in the know especially in such a big project. Maybe they will allow more news if they know we care. I, for one, am very interested in the updates.

Question. With 2 B-29s flying, and intuitive logic saying that 2 airworthy birds will go through spares 2x as fast..what does the store of available spares look like? For how long can both planes be operational before both are rendered for static display? I know the CAF has resorted to a R3350 hybrid engine, but is this due to parts becoming scarce?

[Iclo]

From what I red, the original engine type was unreliable and it's was the main reason of the hybrid engine program for Fifi and now for Doc too.

Having a more reliable engine increase security but reduce the spares required to keep them turning, too

[B-29 Watcher]

It is my understanding that the hybrid engines is a much more RELIABLE than the originals. And like TriangleP said, there are there are a ton of parts out there. If you watch the videos on Docs Freinds at.

http://www.b-29doc.com/announcements.php

He tell us that they are building him (I refer to DOC as male due to the name is male) to fly for the next 30 or 40 years. So no static time for DOC in the near future.

This Conversion is quite elaborate, it involves changing the mounts, the exhaust collectors, all the wiring, fuel lines and on and on. We have not heard if the exhaust collectors have arrived or that any of the engines have been installed. We have been left in the dark. We need Ryguy or Jeremy back to keep us informed.

[Dan K]

...We have not heard if the exhaust collectors have arrived or that any of the engines have been installed...

But wasn't the first engine installed back in November?

http://www.warbirdsnews.com/warbird-res ... 9-doc.html


Exhaust collector installation apparently already in progress on March 12:

http://www.warbirdsnews.com/warbird-res ... pdate.html

[B-29 Watcher]

...We have not heard if the exhaust collectors have arrived or that any of the engines have been installed...

But wasn't the first engine installed back in November?

http://www.warbirdsnews.com/warbird-res ... 9-doc.html


Exhaust collector installation apparently already in progress on March 12:

http://www.warbirdsnews.com/warbird-res ... pdate.html

Thanks Dan K for the up date on the exhaust. That is the first I have heard about the progress. AS for the first engine hanging that is just temporary to see if it fit, according to Jeremy H. I guess I will look more at the warbirdnews for info

THANKS AGAIN

[b29flteng]

Hybrid engines: The original engines (R-3350-57) were unreliable due to poor cylinder cooling. Poor fuel distribution due to poor design of the internal supercharger. Nose case gears were inadequate for the horse power output of the engine. All of this resulted in engine failures. On FIFI we were lucky to get 100 hours out of an engine before it failed and we weren't flogging it like the military did. The hybrid engines were built out of the last version of the R-3350 designed, the -89, -95. These engines had a totally different cylinder design which improved the cooling by about 40%. The nose case gearing was redesigned to be more robust. The internal supercharger was redesigned to improve fuel distribution. The exhaust on the -57 engines front row cylinders exhausted forward in to an exhaust collector ring which contributed to the cooling problem. The later version of the engine exhausted to the rear, that is why a new exhaust system needed to be designed and built.
The term hybrid engine comes from the fact that the new engines are built from two different versions of the late model engines. The nose case and power sections are combined with the aft accessory section from a -26 (Skyraider) engine. The -26 uses a carburetor instead of a fuel injection system, and also bolts right up to the original B-29 engine mounts, so the engine mounts do no need to be modified. The engine cowling needs to be modified to use the different cooling baffles, which direct the airflow around the cylinders.
The new engines are also operated at a reduced power setting. The nose case gearing, which drives the propeller shaft, is different from the original -57 engine in that it turns the propeller faster. As a result the engine is only turning 2,400 rpm vs the original 2,800 rpm. If the propeller was turned faster it would result in the propeller tip speed to exceed the speed of sound. With the lower rpm, the wear and tear on the engine is less and the engine runs cooler. With the combination of 2,400 rpm and 44 inches manifold pressure the new engines produce approximately 2,200 horsepower, the same as the original -57 engines.

[B-29 Watcher]

Thank you Mr. b29flteng;

That tells us (me) alot about why we need to convert to these engines. Also why they are called hybrids. And most of all what are the improvements. That is a lot of information in a very short statment by someone who knows.

[Matt Gunsch]

Just remember who came up with the Hybrid engines,
Gary Austin, they should be R-3350-B29-GA

[menards]

menards, in this case intuitive logic is leading you down the wrong path. Production of the R3350 was enormous for the many aircraft that used it and their spares. Others here can explain in detail the hybridization of these B-29's engines, but AFAIK it did not require a unique or special manufacture of parts. Rather, some elements were swapped for more robust and reliable parts from a later version of the engine, which was also produced in huge quantities. So lots of parts out there for this engine.

Its hard to imagine now in this age of relatively low industrial output, but the production capacity of the US in the 40s, 50s and 60s was defined by being absolutely and categorically enormous.

While I agree that production of R-3350 was enormous, it does not change the fact that it was (is) an unrealible powerplant. Isnt the CAF still having issues with the hybrid? Did that restored DC-7 ever get out of Charlotte after its -3350 expired on takeoff?

[b29flteng]

The new hybrid engine is very reliable. We have over 500 hours on our engines with very few problems, I think we've had one cylinder change due to a loose spark plug boss. Remember the airlines used this same engine and would put 1,500 to 2,000 hours on before overhaul. One reason for the reliability is we are only using 2,400 rpm for maximum power which reduces wear and tear, we are essentially operating at METO (Maximum Except Take Off) power which can be run all day long. With the lower rpm also brings cooler temperatures. I've operated these engines on a 103 degree day and never saw the CHT (cylinder head temp) exceed 200 degrees C. (232 is max). I keep talking about temperatures. Controlling temperatures are the key to successfully operating a large radial engine.


B29driver, Don Davis, Mike Looney, and Rodney Jackson are the folks who came up with the idea of the hybrid engine. B29driver and Gary Austin, and Dave Miller made it happen.

[Brad]

B29driver, Don Davis, Mike Looney, and Rodney Jackson are the folks who came up with the idea of the hybrid engine. B29driver and Gary Austin, and Dave Miller made it happen.

That is 100% the truth and all too often gets lost in the story!

[Iclo]

Perhaps a stupid question : but is a "custom" engine like that require a "certification" ? Was the FAA required to be involved in the whole process ?

And except the components listed in the previous post, is there custom parts in the engine itself or it's basically parts of two engines type bolted together ?