Aquila Aero Prop pitch

[Triker]

Good day everyone

I need someone to pitch my prop thoroughly. I have done it a few times myself in the past but results were not so great as I hoped. I bought another blade which was balanced together with the other 2 blades and the housing for my Rotax 503 Aero prop at Solo wings (strange air bubble appeared on the tip of the old one, so had to replace).
So with a fancy gadget for a warpdrive prop, set my pitch to 13 degrees. But the RPM on the motor ran to about 7000rpm (which is out of the max power band at about 6400 RPM's) According to Solo wings, for every degree = 500 rpm's less This is not what I experienced. Now my motor is revving to 6300 RPM's static, but had to set my pitch at 17 degrees !!

Since last weekend I felt a strange vibration while in the air just as I peak to full rpm's (6400) It feels like a shudder just as I'm about to peak rev. Can it be the prop that's now giving problems because of the high pitch. I also dont get enough power out of the prop.

If there is somebody that knows how to properly pitch a Aero prop for a Rotax 503 Aquila, please let know.

Here is my cell number: 071 351 8897
thanks
Henk

[Triker]

Come on guys. I'm sure somewhere out there, is someone with the expertize of pitching these props?

[Abe]

Hi Triker,
I now again use my Warp Drive bubble level pitch indicator, think it is as accurate as the digital one that has been redistributed. Where along the blade do you take the pitch? Unless you have a small diameter prop 17 deg seems to indicate that you take it too deep inboard. I read somewhere to read at 90% of chord, also not at the tip as I saw recently pictured. Static balance should be OK on a carbon fibre prop, but check it first nevertheless.
Like most old-time pusher-prop flyers I have a fair collection of props on the hanger wall.
The 912 guys can live with Warp Drive inefficiency to have indestructability, but like you, I need a more efficient prop.
I rate Aeros very similar to Powerfin in performance, better than Warp. These all overrev in level flight on the Beaver, but should be OK on a slower trike. GSC wooden prop was better, and Kiev best by far, magic at containing revs. All fragile still, so keep a good grip on your map.
FlySafe!
Abe.

[Triker]

Good day Abe

Thank you for your reply and the valuable info. I also used the bubble level pitch indicator for the warp drive props. It is fairly accurate. Do you perhaps know where I can buy a digital instrument? According to Solo wings, the pitch of the prop must be taken 200mm from the inside of the blade (thus, from the point where the hub meets with the blade) towards the outside length of the blade. There you take masking tape and wrap it around the blade (90 degrees with the edge of the blade). Then with the pitch indicator pitch the prop at 13 degrees. That's precicely how I used to do it.

Question: I assume my trike must be 100% level standing on the floor before doing any sort of pitching as stated above?
I measured one of my older blades and it's about 790mm in length. The prop itself's diameter is not to small (compared to other props that I have seen). The static balance on the prop is fine (no vibrations).


If anyone else knows what the measurements must be for pitching a Aero prop with 503 Rotax (just to make sure I'm correct), please post it here.

regards

[Stephan van Tonder]

I must say that generally we don't actually measure the exact degrees when we do prop pitch. We just make sure they are all the same and you pitch it to where the rpm is contained where you want it.

[mulderpm]

Triker. I replaced two blades on my Aero Prop with second hand ones. I statically balanced the prop and she is good. I used the pitch measuring tool that comes with the prop to measure the pitch. I measured the pitch before I removed the old blades and made it the same. I also, for peace of mind, compared this pitch with some other trikes with the same configuration as mine. All were within ½ degree. She revs 6340 - 6400, which is perfect and the power is the same as always.

I agree with Stephan, the pitch must all be the same and be such that the engine does not exceed 6400rpm (Rotax spec). As the engine gets older she will lose power and you will have to compensate for this with a finer pitch.

[Station Kariba]

Question: I assume my trike must be 100% level standing on the floor before doing any sort of pitching as stated above?

You need to make sure your Propeller hub is 100 % level, if not, you should measure the angle of the engine at the Prop hub, you then add the angle of the prop hub to the desired pitch angle you are trying to set. So you hold the protractor against the hub and take a reading, you then add that to the 13 degrees you trying to set to get the desired setting on the blade. Measure at the hub first, you could also pack the front wheel up to get the hub 100% square to the ground, then go ahead and set the prop to 13 degrees or what ever your desired pitch angle maybe. Hope this helps and good luck.