Prop Pitch

[cactusman]

Originally Posted by rv3flier

After several more attempts to get my prop pitched to get to the 4960-5020 recommended static rpm, I've got it to 5030 with 68.4* on each blade -- (note that the degrees I measured would be different for someone else with differences in the fixture mounted to the digital level, etc.). Unfortunately, I haven't been able to get to fly at altitude as yet due to weather and an intervening trip, but I'll report in a week or so when I get the chance to fly again.

That's exactly what mine is set to. The degrees are pretty close, of course those jigs are very sensitive and the prop isn't exactly flat so it's tough to get the same degrees even with making marks and being careful.

FYI - mine does really well with climb performance but I have noticed it is a bit of a dog in cruise. I just took it on a fairly long cross country to Cortez and while it performed very well taking off at gross in CEZ (5918') and again at Holbrook AZ (~5300') at very high Den Alt - I noticed my actual fuel flow was pretty high, and my speeds should have probably been a little higher.

My guess is that you'll notice better than book performance in TO rolls and climb and worse numbers in cruise/fuel flow.

The nice thing is you can adjust for the mission.

[rv3flier]

Thanks for posting, CactusPilot.

[dbhill916]

I found an interesting wooden tool with my prop that appears to be custom made by them for the setting of prop pitch using a digital level. Did these get added to the kits recently? (Mine arrived last December.) I zeroed a digital level relative to the canopy rail (thanks, Scott!) and then measured the angle of the top of the wooden tool. Thanks to the previous poster who also mentioned that you have to measure the ascending prop blade, and don't assume that the ascending blade angle is the negative of the descending angle.

I have not yet reached the point of doing full power runups, although I have run the engine at idle.

Has anyone else used this with good results?

[tomkk]

That's what I used to set mine and it worked out OK although you have to be a bit careful to ensure the tool is placed on the blade(s) the same each time. If it gets canted side to side it'll affect the reading . It does a great job of conforming to the blade shape but before I use it again I'm going to figure out a way to mount a cross piece that'll lay on the blade edge to ensure the same orientation each time.

I zeroed the level on the rail as well. No biggie, but since we're not trying to achieve a specific reading but just ensuring both blades are the same, I don't think it matters what we zero to, just that it not change while we're doing our adjustment.

Also, I'm not sure why the measurement needs to be taken on the ascending blade. I found it more convenient to do it on the descending blade because the put the relatively flat trailing edge on top so I could use it with a level to position each blade in the same horizontal position before I took my reading.

[rvbuilder2002]

Originally Posted by tomkk

I zeroed the level on the rail as well. No biggie, but since we're not trying to achieve a specific reading but just ensuring both blades are the same, I don't think it matters what we zero to, just that it not change while we're doing our adjustment.

You are correct Tom, but the benefit to zeroing is you can record the resultant angle in the log book. Then later if you remove the prop for some reason (Sensenich specifies that the blades be removed for condition inspection....) it would be easy to reset to the original value without the need to have the airplane sitting in the same spot as before, or have any influence by tire air pressure etc., because it is a fixed reference.

Originally Posted by tomkk

Also, I'm not sure why the measurement needs to be taken on the ascending blade. I found it more convenient to do it on the descending blade because the put the relatively flat trailing edge on top so I could use it with a level to position each blade in the same horizontal position before I took my reading.

Correct again. It can be done on either side. The main requirement is that both blades be in the exact same rotational position when the measurement is taken. Most people tend to use the descending blade position if they have made their own tool because it is easy to make it hang on the trailing edge repeatably.

[tomkk]

Originally Posted by rvbuilder2002

You are correct Tom, but the benefit to zeroing is you can record the resultant angle in the log book. Then later if you remove the prop for some reason (Sensenich specifies that the blades be removed for condition inspection....) it would be easy to reset to the original value without the need to have the airplane sitting in the same spot as before, or have any influence by tire air pressure etc., because it is a fixed reference.
...

Good point, makes sense ...

[BigJohn]

Has anyone checked to see if the wooden gadget can be ordered from Sensenich? My home brew jig with the level strapped to it works pretty well, but this appliance might have the potential to make pitch setting even more accurate and repeatable.

[rvbuilder2002]

I personally think the home made tools are better because you can make it so the digital level or protractor attaches to the tool.
With the Sensenich tool you have to hold the level up against it (one more error variable also).

I think a pre-made tool might be available from Van's in the future, but I am not sure when. Keep a watch out for an announcement.

[rv3flier]

I managed to get up today after being out of town for awhile. Static = 5030 rpm; Climb out at 75Kts with 1/2 flaps = 5230 rpm; At 8500' 8*C full throttle = 5650-5680 rpm. Seems as though I'm pretty close to the recommended numbers.

[dinowal]

After a long taxi warmup, I tried a full throttle static run. Only managed 4550 rpm. I have to fine the prop up a bit,- I have read that small adjustments make a big difference, - can anyone give me a rough guide on how many degrees or parts of a degree to go? Thanks for any help, Cheers, DEAN....