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  #71  
Old 06-15-2015, 06:20 AM
Dave12 Dave12 is offline
 
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I would think upward of 1 degree to start with. Be mindful to check the static rpm in a no-wind condition. It might take a bit more than that, but I would start there.
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  #72  
Old 06-15-2015, 07:07 AM
Sink Sink is offline
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It would be interesting to know what your final degree change is when your done. I have found different props need different settings for static.

You need roughly a 400+ rpm change.
I'll throw my dollar into the hat and say at least a 1.75 degree flatter change and possibly more depending on your average altitude to get around
5600-5650 WOT rpm at your AVERAGE altitude. The average altitude will be the kicker for that fine tuning. Some are low fliers and some are high.
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  #73  
Old 06-15-2015, 07:08 AM
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rv3flier rv3flier is offline
 
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Location: La Center WA
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FWIW I started out with a static of 4700 +/- 20 and a blade average of 66.0 (one at 65.7 the other at 66.3) and ended up with 5030 static and 68.4 degrees on each blade. So, in my situation I gained 310 rpm with a 2.4* change.
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  #74  
Old 06-20-2015, 04:49 PM
dinowal dinowal is offline
 
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Location: TWIN WATERS, Queensland, AUSTRALIA
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Thanks very much for your suggestions, guys, - Sink, you win the prize!! we moved it 1.7 degrees flatter, - now the static full RPM is 5020, - Happy with that. We didn't measure the angle to Horizontal or Vertical, so I can't help with that.. The aircraft has not flown yet, - hoping for a good compromise between climb & cruise performance... Cheers, DEAN...
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  #75  
Old 06-20-2015, 09:46 PM
Sink Sink is offline
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Hi Dean,


Glad it's coming together for you.
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  #76  
Old 06-21-2015, 05:47 AM
Dave12 Dave12 is offline
 
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Quote:
Originally Posted by dinowal View Post
Thanks very much for your suggestions, guys, - Sink, you win the prize!! we moved it 1.7 degrees flatter, - now the static full RPM is 5020, - Happy with that. We didn't measure the angle to Horizontal or Vertical, so I can't help with that.. The aircraft has not flown yet, - hoping for a good compromise between climb & cruise performance... Cheers, DEAN...
Dino, just curious if you see book cruise numbers without exceeding 5500 rpm with this setting?
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Wag Aero Sport Trainer built,sold and wrecked
N588DF RV12 #336 built, sold and alive and well in New York
N73DF RV12 #244 built, sold and alive and well in Florida
N91 RV RV9 I wish I could say I built this one! Mark Santoleri hit the ball out of the park on this gem.
Currently restoring a 1978 Citabria GCBC
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  #77  
Old 06-21-2015, 05:49 PM
dinowal dinowal is offline
 
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Location: TWIN WATERS, Queensland, AUSTRALIA
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Hi Dave, It hasn't flown yet, -soon,soon! Probably will fly on Tuesday, - just don't know which Tuesday! Cheers, DEAN..
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  #78  
Old 06-21-2015, 06:35 PM
Dave12 Dave12 is offline
 
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Quote:
Originally Posted by dinowal View Post
Hi Dave, It hasn't flown yet, -soon,soon! Probably will fly on Tuesday, - just don't know which Tuesday! Cheers, DEAN..
Best of luck Aussie Brother, let us know how she does. Lots of flights scheduled for tuesday! Al from Albania is also scheduled on this date.
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Wag Aero Sport Trainer built,sold and wrecked
N588DF RV12 #336 built, sold and alive and well in New York
N73DF RV12 #244 built, sold and alive and well in Florida
N91 RV RV9 I wish I could say I built this one! Mark Santoleri hit the ball out of the park on this gem.
Currently restoring a 1978 Citabria GCBC
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  #79  
Old 06-22-2015, 12:46 PM
funflying funflying is offline
 
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Location: arvada, co
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Hey Dave,

I too get static run-up at 5020 and my cruise at 5450ish is 103kts consistently. This RPM, 5450, is usually were I try to stay in cruise.
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  #80  
Old 06-08-2016, 08:55 PM
chasers03 chasers03 is offline
 
Join Date: Aug 2015
Location: Seneca, SC
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Default Best Rotax WOT rpm

Everything I have ever read from Rotax on the 912 ULS says that you should not be running 5500 RPM or higher for longer than five minutes. Ref. Royal operators manual.

"You already have a flying aircraft so static is probably already close and it flys so you need to just fine tune the pitch for the best all around balanced performance since we use ground adjustable props. After a few years of testing for different companies the best all around Rotax WOT rpm at your average altitude is around 5600-5650 rpm at WOT in flat and level flight.
If you live in Los Angeles and never fly over 3K then set it for that. If you live in Mammoth, CA with a field elevation of 7100+' and always fly at 11K-13K then the pitch should be set for that.
Never have the prop adjusted so it is below 5500 rpm at WOT.

Mark each blade with a mark approximately 8"-9" back from the tip on each blade. Always loosen the larger 8mm hub bolts first and no need to loosen them any more than you can turn them by hand when loose. Face the plane and rotate the first blade around so it is on your right. Place the level on the blade so it is level with the ground. If we do this for each blade they will all be equal. Now place the level on the back side of the blade so one end points to the floor. Put the rubberband around the tips of the level around the blade and it will hold it in place. Look at the pitch on the level. It really doesn't matter at this point what the exact number reading is. If you need 1/2 degree adjustment to a finer pitch then loosen the other prop bolts until you can turn the blade so it is 1/2 degree flatter than the original reading. Snug the blade bolts back up, but don't worry about torquing them until you are done. Now remove the level and do the same for the other blade(s). Once done double check each blade before you torque the bolts up. Always torque the large 8mm bolts first. These are first to loosen and first to tighten. If you needed a different degree adjustment then that is what you would have done. Now go fly and see if your WOT rpm in level flight is around 5600-5650 rpm. This tends to give you the best climb, cruise, top end speed and fuel economy."


Here is a good article on prop pitch:

http://ctflier.com/index.php?/blog/6...justable-prop/


Hope this helps some.[/quote]
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