WIX Archives

Hydraulicing and hand-turning props (longer post)

Posted by Dan K on Thu Sep 25, 2003 03:02:56 AM

Hi All,

Don't know if this topic has been approached on the WIX before, but here goes: The recently-posted photos of the Collings Corsair reminded me of an on-going debate on how to best handle oil that puddles up in the lower cylinders on big radials. My time-warped excuse for a memory seems to recall reading an article in which the author (Randy Sohn maybe?) voiced his opposition to the hand turning of props before flight. The line of reasoning inferred that the force of two grown men pushing/pulling on the end of a long lever (like the propellor blade of an F4U, P-47, or B-29) is more than enough power to put a crack in the rod of a piston which is unable to reach TDC due to excessive oil trapped in the cylinder. The author's suggested approach was to energize the starter for short, repeated intervals to "feel" for any pistons experiencing hydraulicing.

The biggest thing I've got in my shop is a Ranger inline 6, so I can't claim to be a round engine expert. I'm just curious as to what experiences others have had, and since this board claims to be an informational exchange maybe we can save someone from a nasty and unforeseen surprise.

Best wishes to all,
Dan

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