on_your_six.......LMBO......this thread went from how to check prop tracking to how to make a hole bigger and not even needing to be centered.....[:-][:-]
i gave up several posts ago as you just cannot argue with "backyard" mechanics...........i beat them in competitions all the time though so they are required to be part of this hobby........
funny thing is, no one has posted the proper way to true up a prop................should we give in and explain it?.......nah.......the ol rasp file users will jump in and claim they know.

Bad tracking or blade balancing ?


http://news.yahoo.com/blogs/technolo...224458312.html

Ground resonance. A 4 point oleo strut type of landing gear and a fully articulated rotor system. His only recourse would have to been take off once in it got into it that bad.They must have edited out the hard landing on one of the struts.

summerwind - no secrets here! What type of competitions did you participate in and yes, please explain the proper way to true up a prop. Good info is good info, no matter how many rasp filers there are around here.

Kurt

Looks like the pilot just sat there and let it happen.

Even a small gust can induce ground resonance, or sometimes nothing at all, as depicted here:

http://www.youtube.com/watch?v=-LFLV47VAbI

This wasn't a 'ground resonance test gone wrong' despite the label, it was a run-out airframe at an Army maintenance depot, and someone had the idea to film the outcome for training. Full-scale heli pilots (may not include Brazilians) are cautioned against prolonged idling under power for just this reason.

on_your_six.......LMBO......this thread went from how to check prop tracking to how to make a hole bigger and not even needing to be centered.....[:-][:-]
i gave up several posts ago as you just cannot argue with ''backyard'' mechanics...........i beat them in competitions all the time though so they are required to be part of this hobby........
funny thing is, no one has posted the proper way to true up a prop................should we give in and explain it?.......nah.......the ol rasp file users will jump in and claim they know.
[/quote]


Summerwind,

Sounds like your just the guy to give us that information. Us old rasp filers would greatly appreciate the sharing of your knowledge.

physics  boys..... balance and fly....

Here is APC props recommendation for prop reaming with a tapered reamer. Read the section titled "Engine shaft hole alignment".

http://www.apcprop.com/v/html/tech_s...html#holealign

Thanks Tacx. Straight from APC. This settles this question.......

Mustangman,

Your welcome. I think throughout our discussion there was some confusion as to what we were trying to accomplish. Some of the other posters were providing input in regards to the trueness of the engine shaft and drive washer. That's another animal. We were discussing the tracking of the prop only.

As someone has mentioned, if you are checking the trueness of the drive washer you would have to use a testing bar that is known to be perfectly straight. I personally have never tried to check the trueness of a drive washer, but I guess it may be necessary if an engine were crashed?

Anyway, as for the prop itself I have used the tapered reamer for years and have been very happy with the results.

Tacx,
Your method worked fantastically. I bought a tapered reamer ($7), put the new 3 blade master airscrew propeller on the fl70 and the tracking was perfect. I did the same with another 13X6 APC on my saito and the tracking was at 1/16", which I feel is acceptable.

Thanks again<br type="_moz" />

Glad to help. The sharing of info is a wonderful thing !!