I thought on radial engines before starting you walk the prop through to remove oil from the lower cylinders. How do you do this if the engine(s) are too high to reach the props such as on a PBY? Is there an alternative method such as a bleed valve that is employed?
Radial engine prop walking
- Thread starter RonP
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EvilEagle
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You pull the blades through to check to see if any of the lower cylinders have filled with oil. If they have, you have to remove plugs and drain & clean them, you have to STOP pulling through as soon as you feel more resistance than normal.
On big stuff like our B-29, the starter motors have a clutch in there that will cut out if it gets enough resistance that it could be a hydraulic lock. On some stuff (AN-2 for instance) you have to use a rope to throw around the blades and pull them through.
On big stuff like our B-29, the starter motors have a clutch in there that will cut out if it gets enough resistance that it could be a hydraulic lock. On some stuff (AN-2 for instance) you have to use a rope to throw around the blades and pull them through.
If it was on the water they usually had tender boats that would assist in this or with some similar aircraft the wing leading edge folded out to make a platform. But as mentioned, you pull the prop to check for lock and not remove the oil. However, while it is generally prohibitive to turn the prop backwards to clear the lock, there were several specific engines that had oil drain tubes in the lower intake tubes to do that.
Rene
Pre-takeoff checklist
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Rene
See if Periscope (or similar) has digitized old film of the Cat. It's amazing what I've learned from watching old industry and military films. (Now . . . who at PoA has a B-17 so I can practice what I've learned.)