View Single Post
  #1  
Old February 18th 08, 11:35 AM posted to rec.aviation.owning
Denny
external usenet poster
 
Posts: 562
Default When to replace a prop?

Well, ya just never know what little surprise you will find...

My Hartzell props are non-AD replacements to get the annual prop AD
off my back... Blades never nicked, never filed, etc.. Have under a
thousand hours on them... We weren't even looking at them as needing
service... But, I wanted to change out the front seal on the right
crank as it has a slight drip that keeps me busy cleaning things
off...

So, the little surprises began to happen...
When we pulled the right prop to do change the seal we found the studs
had been over tightened. Two nuts were slightly rounded off in
breaking them loose... Oh well, stuff happens and The Kid added new
nuts to the parts list... So, the seal is replaced, we hung the new
cylinders finally, and The Kid went to put the prop back on the next
day... I get this call at the office...

"you ain't gonna believe this."?", my wallet started to itch
immediately...

"Believe what?"

"The flywheel is cracked."

"Steve, in 50 years of owning airplanes and longer than that messing
with engines I have never seen a cracked flywheel on an airplane
engine."

"Neither have I, but it is cracked. I had just hung it on the crank
and lifted the prop up and as I was lining up the bolt holes the light
hit it just right and I saw the crack"

"Ah jeez... OK, leave it till I get there this afternoon."

So, I get there and sure enough, with the light "just right" you can
see the crack $$ So, I stare at the other prop and say, do you know
what I'm thinking... He says, yup, and we push the tool box around to
the left engine... Well, now I'm here to tell you the gorilla that
mounted the left prop must have used a 4 foot wrench to tighten the
studs... It took the better part of an hour of finesse and finally
resorting to a big drift and an even bigger hammer to get two of those
nuts broke loose... But the good part of that is after dye penetrant
the flywheel is not cracked... So now we have a new set of studs and
nuts for both engines on the parts list, and a flywheel - hoping to
find a used one for half the new price... Keeping old airplanes
flying is a full time job...

denny