How A Pontiac Pushrod Saved a B-29 Bomber (with video)

It looks beat-up because it’s not so easy to keep a B-29 in flying order. The original Curtiss-Wright R-3350 engines were 1940s-era turbo/supercharged radials, and finding components to repair them was a full-time job. “In 2006 we had just overhauled our last serviceable spare,” flight engineer Don Obreiter told us as we stared up at the exhaust-smudged nacelles. “It came with a five-hour warranty, and in our sixth hour of break-in time we had a failure.” The plane’s crew chief had the idea to create hybrid replacement engines, not in the electric/gas way, but from a mix of parts from later 1950s Skyraider and Boxcar engines, supercharged only, and much easier to repair and maintain. Each engine has a 13.5-inch-diameter supercharger impeller driven off the back end of the crank and spinning at 6.45 times the crankshaft rpm. Originally fuel injected, they have been retrofitted with Bendix PR-58 pressure-injected carburetors. Sometimes, you just can’t beat a carb. The 18-cylinder engines are made of steel and magnesium, with a bore of 6.125 inches, stroke of 6.312 inches, displacement of 3,347 cubic inches and a dry weight of 2,670 pounds.

via How A Pontiac Pushrod Saved a B-29 Bomber (with video).

Here’s a pretty nifty article on some of the tricks and cheats CAF has to go through to keep FiFi flying. I’m not a gearhead, so some of it goes right over my  head.

But the last part of the article talks about the challenge of the APU. Which, it was, if memory serves, an APU fire that caused the loss of Kee-Bird in Greenland.

4 thoughts on “How A Pontiac Pushrod Saved a B-29 Bomber (with video)”

  1. The acronym APU stands for two similar but different things – Auxiliary Power Unit or Airborne Power Unit.

    An Auxiliary Power Unit is a substitute for a ground power cart. It is only supposed to be used to provide electrical power (and bleed air) while the engines are shut down on the ground. Once the engines are started the Auxiliary Power Unit is supposed to be shut down prior to taxiing.

    An Airborne Power Unit can be used on the ground or in the air, it has the airworthy fire containment, detection and extinguishing systems that the auxiliary lacks. It is normally used to start the engines, is kept running during takeoff, is shut down in cruise, and then restarted during descent. Should an engine fail on take-off or on a go-around the APU driven generator will take the load as the engine driven generator drops offline.

    The idiots aboard Kee-Bird didn’t understand the difference between the two.

  2. Poor Kee Bird! After all these years I’m still hurt by those idiots burning her up.

  3. Worse yet watching them watch it burn!! I turned off the TV, couldn’t bear anymore.

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