Prop Overspeed in Cruise

D

Dean3238

New member
Like many others, I always had my 14-19 run over redline a little on the take off roll, and pulled the prop back after takeoff to get it in line.

Last year I had my engine replaced with a zero-time O-435A (and prop overhal done) and now it zips way high on take off (3000) and once at cruise I'm pulling 20 inches and 2700 (!) with the prop _all_ the way back (and 165 mph).

Once I get down to pattern speeds, the prop control functions in the normal range.

I checked the static RPM at max MP and got redline and no more, so the stop screw on the prop is set properly. Replaced the tach to see if it was an instrument problem.

I presume my problem has to do with the stroke of the rubber piston or maybe the counterweigths, but know I'm out of my league when it comes to fixing it.

Ideas?
 
Dean >yeah our boys sang the same song. We moved the blades and solved the problem. they quit singing after we told them that. LYNN Of course there was no money back. Spent a thousand bucks for a yellow tag. :x :x
 
Lynn,

Talking to the Hartzell people, it seems that the blade stops may need to be adjusted to reflect the HP the new engine overhaul is putting out. Working with them to figure out how to get this done and it is something that must be done on the aircraft with the prop installed.

The prop shop didn't change the old stop values (they wouldn't have known to do anything with them) or (I suppose) they could have set them to the factory default locations.

Is that what you guys had to do?

Dean
 
Yes that is what we had to do. We moved the blades a small amount 3 times each time we did this, we got closer to what we wanted. So we knew we were on the right track. Navion has been fine ever since. LYNN :D
 
Lynn, you are just the guy I need to talk to, then :lol:

I don't know if you feel comfortable giving more details on what you had to do on-line, but if you could describe it in detail that would be wonderful (treat me like you are explaining it to a four-year-old). Remember, I'll be attempting to explain this to my A&P.

If you'd rather do it privately, drop me a line at d.essig@insightbb.com and if need be give me your phone number so I can talk about this.

My Bellanca is a wonderful bird and the new engine has all kinds of pep, and I certainly don't want to tear it up with a prop that isn't adjusted right.

Thanks!
 
Don't know if you solved your prop problem, but when all else fails replace the tach. Sometimes works wonders, and its pretty cheap.
 
Thanks (actually did that early on, didn't do the trick).

I ended up putting in cone spacers to push the prop mounting further out. Found out this was all caused by the new engine I had installed... the crank was just a little longer than the old one, causing the distances in the prop spinner to get out of whack.

Works great now.

Dean
 
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