Crank Runout

i know this is vauge but what is typical (if such) of runout on a engine with a mangled fixed pitch prop., one blade bent back about a foot and the other fwd 6 or so inches...i guess my question really is when a prop strike occurs and runout is measured are all,some or a few cranks bent?

[Vern]

Sorry, but this engine would need a tear-down to insure that it is airworthy.It may be, but you cannot tell until the basic components are checked. Therefore, it may not be a bargain by the time you disassemble,reassemble, do parts checks, buy gaskets,etc.

[tacchi88]

Min. to max. run out allowed for Lycoming is .002. Maximum serviceable .005. If the engine had a prop strike, with Lycoming, in certified AC is a mandatory teardown. Rule may differ with a bit with Exp., but the wise will tear the engine and inspect for further damage, more often than not invisible to the naked eye. It's a **** shoot.
T88

[szicree]

Can somebody please read the original poster's question again so that he can have it answered?

[mahlon_r]

Different OEM'S can use different manufacturing techniques, when making a crankshaft. Typical Lycoming crankshafts are not hardened right behind the crank flange and they tend to bend more easily, from a prop strike, then other crankshaft manufactures that have crankshafts that are hardened in that area. So the amount of bend form a given prop damage situation may vary by engine manufacturer due to differences in the way the shaft was manufactured.
The effect of a prop strike on the engine can be varied by the circumstances around that incident. One crankshaft might be bent significantly with less damage to a prop, then one that's prop was destroyed but the flange dialed within limits. So it is difficult to answer your question, as prop damage like you describe might have no flange run out under one set of circumstances and run out past limits in others. There is no rule of thumb.
Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at you own risk."