REFLECTOR: MT Prop failure mode.

[Bernard Despins]

We have adjusted the low pitch stop many times.  I checked it, and the 
safety wire seemed intact. I will have another look.

Bernard

davedent at comcast.net wrote:
> Berand, I have run into this problem before.  With the MT props the low 
> pitch stop needs to be adjusted sometimes and it can get out of position if 
> the two jam nuts on the low pitch stop is not locked together correctly.  I 
> have found three MT props not correct right out of the box.  Most don't come 
> safetied, because it needs to be adjusted in most cases. Lock the two nuts 
> together and safety them together to keep them that way.  Use .040 wire. 
> They move every time you change pitch.
>
> Once I found one where the safety wire for the two nuts was secured to one 
> of the fwd plate hold down bolts, so doing made the nuts so they couldn't 
> move with the shaft like they should during pitch change.  They must be able 
> to move fwd and aft during pitch change.  This also caused the nuts while in 
> the high pitch positions to move further forward and changed stop to a 
> greater pitch and eventually couldn't get it to come up to even governor 
> control speed.
>
> Right now it looks like to me the stop is not adjusted correctly and you may 
> have to add some more bite into the low pitch position.  To do this, just 
> brake the two nuts apart and rotate the inner one towards the cover plate. I 
> have found that if you have five threads showing after the jam nut is tight 
> to the inner nut, it's just about right. It may take another flat on the 
> inner nut to get it just right but you can't tell this till you are 
> unloading it as you start you take off roll.  Then you may have to move it 
> just a flat or two more for good take off performance. This comes into play 
> when you do your first high speed taxi test.
>
> If you are getting the 2700rpm then the governor is working great and it's a 
> stop issue.  If the inner plug in the inside of the crank is not plugged you 
> couldn't get your governor to work and maintain the 2700rpm.  This don't 
> seem to be your problem. If you can change pitch at all then the governor is 
> working.  Let me know how it turns out.
> Dave 
>
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