Thread: Problems pitching prop
12-25-2008, 01:58 PM #1
Problems pitching prop
I removed my oem impellor and made up some pitch gage's and am trying to increase the trailing edge pitch. What's happening though is that I'm getting a "kink" forming on the blade's (3 out of 4) and they still aren't reaching factory pitch. I think it's supposed to measure at 13/23 or 24 and 1 blade was close at 23.5. The others were 21, 21, and 22. I had the 3 bad ones close to 24 but they had a BAD bend in them. I'm using the instructions from here. Using the biggest crescent wrench I have. Is this common or am I a duschbag. With the prop sitting on a flat surface the trailing edge on the good blade is parallel with the surface. The other 3 droop at the outside edge. I went ahead and unbent the kink a bit and headed for the computer.
12-25-2008, 02:40 PM #2
12-25-2008, 03:32 PM #3
Seagoat, nice findings. My T-X stock prop was not correct either. Suppose to be 14/23 and was 12.5/21.5. Similar to your findings.
The problem you are going to have is making the prop progressive pitched all the way down the blade. This is very dificult without the right tools.
I would try to get your blades all similar with more pitch then you had on trailering edge to begin with to get you off limiter.
I would not jack with the leading edge being the first time for you to bend a prop.
Since most of your blades 21,21,22, I would try to pitch them all to like 22.5 or 23. That much will make a big difference in rpm.
12-25-2008, 03:43 PM #4
The leading edges were all very close and I matched them up at 13 with no trouble (3 were already 13). The problem was trying to reach 24 with the trailing edge caused somewhat sharp bend to start forming about 1/2 inch above where I was putting the wrench. I used the vise to reduce this bend and am going to try and take it out altogether. Obviously there's some art work involved here and you have to move the wrench around to get uniform results.
12-25-2008, 04:10 PM #5
sounds like you have done well. I think around 23 will get you close to your rpm needs right.
12-25-2008, 09:38 PM #6
- Join Date
- Aug 2006
- Gonzales, La
Just an FYI, I believe the factory doesn't specify, manufacture, and measure pitch per se. I believe, based on my measurements, that the stockers are specified based on blade height, not blade angle.
A stock prop LE angle varied by 0.8 deg, blade to blade, while the TE varied by 1.7 deg. Sounds bad at first, but the blade height only varied by a maximum of 0.7 mm.
Conversely, a Solas 15/20 LE and TE angles varied by less than 0.3 deg. However, the blade height varied up to 1.2 mm, blade to blade.
Basically, the stock prop blade height was very consistent but the angle was not, and the opposite was true for a Solas prop.
I have no inside line on this, only a bunch of measurements, so it could be all wrong.
12-25-2008, 09:52 PM #7
12-25-2008, 09:57 PM #8
I think will work well. Remember up until now you were running 21, 21, 22, 23. So thats why i think 23 - 23.5 will be good.
12-25-2008, 10:10 PM #9
12-26-2008, 12:45 PM #10
Here's some pics of the prop. I used a small smooth jawed vice and did my best to reduce the "kink" the blades had in them. Now i'll go back to the big vice and unbend as best I can and then work up and down on the blade to try and copy the #1 blade which had a more progressive change to the pitch on the last 2 inches. The pics are of the blades as I numbered them...1 thru 4.
DOH! Wrong button!
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