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  #21  
Old 07-11-2018, 01:20 PM
rvbuilder2002 rvbuilder2002 is offline
 
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Quote:
Originally Posted by AirHound View Post
Sorry for sounding simple here. As an overthinker/underdoer, I find it real difficult to smoothly and consistently obtain the VANS desired prop pitch setting just by loosening bolts and hand twisting blades . My idea to gain leverage is to loosen bolts juuuust enough to barely move blades, then retighten/snug-up/torque bolts without effecting the desired blade angle......seems a little leverage is called for to achieve satisfactory results on a consistent basis. I haven't checked my own idea (tape a lever to the blade to more precisely adjust it within specs/tolerances). Just wanted to see what tips or tricks others in the forum may have learned to achieve best results....Any thoughts out there???
In the shop at Van's we use a tool made of plywood that is about 3 ' long.
It hooks on the blade and provides additional leverage for making small blade movements while setting the pitch.
You do need to be careful because the blades are hollow so you could do damage if the blade camp bolts were still too tight. When using a tool like this, the blade should move with very little force. If not, the clamp bolts are still too tight.

Regarding Van's recommended pitch being too course......
It actually matches up with what Roger (past poster in this thread) and other shops (such as Lockwood Aviation) use.
Additionally, during Aero Friedrichshafen (a large aviation trade show in Germany that is heavily attended by Rotax personnel) this past spring, Van's had a face to face sit down meeting with some of the Rotax staff (including the head engineers for the 912 engine program).
The chart in their documentation, and how Van's engine RPM during climb compares to the chart was one of the topics discussed. In a nut shell the engineers said that the climb RPM's typical on an RV-12 using the general pitch recommendations made by Van's, are not a concern to them.
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  #22  
Old 07-11-2018, 01:23 PM
rvbuilder2002 rvbuilder2002 is offline
 
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Originally Posted by waterboy2110 View Post
I agree with Roger that many are over pitching their prop - Vans is no exception. There have been posts from the Vans folks in this forum that make the claim that the recommended pitch for the 12 won't harm the engine which is incorrect. WOT level flight of 5650 is optimum and SL912-016 describes the types of environments that can lead to engine failure. The 12 suffers from several precursors. Rotax developed these parameters from experience.
Stating a WOT at level flight RPM without stating an altitude is leaving an import piece of info out that is relevant to proper propeller pitch.
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  #23  
Old 07-11-2018, 03:06 PM
AirHound AirHound is offline
 
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Quote:
Originally Posted by rvbuilder2002 View Post
In the shop at Van's we use a tool made of plywood that is about 3 ' long.
It hooks on the blade and provides additional leverage for making small blade movements while setting the pitch.
You do need to be careful because the blades are hollow so you could do damage if the blade camp bolts were still too tight. When using a tool like this, the blade should move with very little force. If not, the clamp bolts are still too tight.

Regarding Van's recommended pitch being too course......
It actually matches up with what Roger (past poster in this thread) and other shops (such as Lockwood Aviation) use.
Additionally, during Aero Friedrichshafen (a large aviation trade show in Germany that is heavily attended by Rotax personnel) this past spring, Van's had a face to face sit down meeting with some of the Rotax staff (including the head engineers for the 912 engine program).
The chart in their documentation, and how Van's engine RPM during climb compares to the chart was one of the topics discussed. In a nut shell the engineers said that the climb RPM's typical on an RV-12 using the general pitch recommendations made by Van's, are not a concern to them.
WOW, that is good to know! Any chance of a photo? Suggestion, how more capable/effecient would owner/maintainers be if our special tool kits contained one of those 3" thingy miJobs which kinda goes, hand in hand, with VAN's blade angle measurement fixture....Another hot seller for the store. Or, maybe just a photo of VAN's stick and a trip to local hardware store to fabricate something...is best?

Lastly, is my following interpretation of your last sentence above correct? "The ROTAX RPM response factors in related Manifold Pressure: Therefore it is no concern if prop pitch configurations and RPM indicate 27.6 and higher (ie;29.5) MAP at WOT RPM (49-5100) on take-off/climb to cruise. Any DA. Hope this question is accurate...

Very Respectfully,
Doug
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  #24  
Old 07-11-2018, 05:46 PM
Piper J3's Avatar
Piper J3 Piper J3 is offline
 
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I believe 4900 is logging the engine in climb.

Need ~ 5200 RPM when climbing ~ 1000 fpm at 1000 MSL on a standard day.
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Jim Stricker
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PPL/ASEL 1970 - Sport Pilot since 2004
80 hrs Flying Aeronca Chief 11AC
1130 hrs Flying 46 Piper J-3 Cub
RV-12 E-LSA #120058 AWC Jul 2012 - Bought Flying Oct 2015 with 48TT - Hobbs now 400

LSRM-A Certificate 2016
Special Thanks to EJ Trucks
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  #25  
Old 07-11-2018, 07:21 PM
AirHound AirHound is offline
 
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Originally Posted by Piper J3 View Post
I believe 4900 is logging the engine in climb.

Need ~ 5200 RPM when climbing ~ 1000 fpm at 1000 MSL on a standard day.
I guess I got carried away with my limited ability to determine if average WOT/Take off/climb rpm ~5000 rpm and manifold pressure ~ 29.5 is ok?

Then at altitude rpm range 5200 to 5500 at 26.5-27.5 manifold pressure.

So, high manifold pressure on take off and climb then normal after reaching cruise rpm 5200-5500 rpm. Is that OK?
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  #26  
Old 07-11-2018, 07:47 PM
funflying funflying is offline
 
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I have been struggling lately trying to get my prop pitch adj. to achieve those RPM ranges I noted from past threads. WOT in level flight was giving me 5720 so I had been inching in the pitch about .2 at a time, but see little to no change. What I am shooting for is 5500-5650.

I had actually constructed a similar device as previously mentioned using a 1x6 board, about 36" long. I cut a hole in the upper portion that was close to the shape of the prop blade and lined the opening with felt for padding. I use it as a lever to move the blade while keeping the bolts fairly snug. I also find the pitch and matching the pitch on both blades is tough. However, it is still difficult to hold a pitch point. Even with the bolts "snug" when the prop is moved the pitch can change. When I torque the bolts the pitch changes. During my last conversation with Sensenich when I would mention how difficult the prop is to set the pitch and hold the pitch while torqueing I was told "yes it is."

I am going to do a few more tests to try and achieve something close to 5650 at WOT, and if I can not get the prop to hold the pitch I'm torqued to I will be sending the hub to Sensenich for inspection/verification of proper milling/clamping specs.
I
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  #27  
Old 07-11-2018, 09:08 PM
AirHound AirHound is offline
 
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Quote:
Originally Posted by funflying View Post
I have been struggling lately trying to get my prop pitch adj. to achieve those RPM ranges I noted from past threads. WOT in level flight was giving me 5720 so I had been inching in the pitch about .2 at a time, but see little to no change. What I am shooting for is 5500-5650.

I had actually constructed a similar device as previously mentioned using a 1x6 board, about 36" long. I cut a hole in the upper portion that was close to the shape of the prop blade and lined the opening with felt for padding. I use it as a lever to move the blade while keeping the bolts fairly snug. I also find the pitch and matching the pitch on both blades is tough. However, it is still difficult to hold a pitch point. Even with the bolts "snug" when the prop is moved the pitch can change. When I torque the bolts the pitch changes. During my last conversation with Sensenich when I would mention how difficult the prop is to set the pitch and hold the pitch while torqueing I was told "yes it is."

I am going to do a few more tests to try and achieve something close to 5650 at WOT, and if I can not get the prop to hold the pitch I'm torqued to I will be sending the hub to Sensenich for inspection/verification of proper milling/clamping specs.
I
Double dang!!
All thread tips considered, can anyone please tell me if 29.5 MAP/5100 RPM WOT at takeoff and climb-out is acceptable based on the Vanís Rotax discussion Scott referred to?
Thank you!
Doug
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  #28  
Old 07-11-2018, 09:40 PM
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Piper J3 Piper J3 is offline
 
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Quote:
Originally Posted by funflying View Post
I have been struggling lately trying to get my prop pitch adj. to achieve those RPM ranges I noted from past threads. WOT in level flight was giving me 5720 so I had been inching in the pitch about .2 at a time, but see little to no change. What I am shooting for is 5500-5650.

I had actually constructed a similar device as previously mentioned using a 1x6 board, about 36" long. I cut a hole in the upper portion that was close to the shape of the prop blade and lined the opening with felt for padding. I use it as a lever to move the blade while keeping the bolts fairly snug. I also find the pitch and matching the pitch on both blades is tough. However, it is still difficult to hold a pitch point. Even with the bolts "snug" when the prop is moved the pitch can change. When I torque the bolts the pitch changes. During my last conversation with Sensenich when I would mention how difficult the prop is to set the pitch and hold the pitch while torqueing I was told "yes it is."

I am going to do a few more tests to try and achieve something close to 5650 at WOT, and if I can not get the prop to hold the pitch I'm torqued to I will be sending the hub to Sensenich for inspection/verification of proper milling/clamping specs.
I
Are you using Vans TOOL-00002 Prop Pitch Bracket per SECTION 47: SPINNER & PROPELLER Page 47-07? I find this tool very easy to use with excellent accuracy and repeatability. Follow instructions exactly using a high quality digital level for the blades and and high quality bubble level on the hub. My blades are set to 0.1 degree and engine is extremely smooth in cruise. It shouldn't take more than 30 minutes to set blade pitch...
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Jim Stricker
Hinckley, Ohio
EAA #499867
PPL/ASEL 1970 - Sport Pilot since 2004
80 hrs Flying Aeronca Chief 11AC
1130 hrs Flying 46 Piper J-3 Cub
RV-12 E-LSA #120058 AWC Jul 2012 - Bought Flying Oct 2015 with 48TT - Hobbs now 400

LSRM-A Certificate 2016
Special Thanks to EJ Trucks
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  #29  
Old 07-12-2018, 06:54 AM
funflying funflying is offline
 
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Thanks for the reply Jim. I use a digital level with a fixture attach to the level I made based on an article titled, Pitch Perfect. The fixture firmly attaches to the level and is in the shape of a T. The horizontal of the T has a lip to guide me on the trailing edge, and the vertical of the T is shaped pretty well to the contour of the prop.

I did use another level to level the prop each I rotated the prop but after a conversation with Sensenich the tech felt the prop needed to be level but using a level each time was a bit much. I use a reference mark each rotation to get the prop in the correct spot to check the pitch angle.
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  #30  
Old 07-12-2018, 07:11 AM
AirHound AirHound is offline
 
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Quote:
Originally Posted by funflying View Post
Thanks for the reply Jim. I use a digital level with a fixture attach to the level I made based on an article titled, Pitch Perfect. The fixture firmly attaches to the level and is in the shape of a T. The horizontal of the T has a lip to guide me on the trailing edge, and the vertical of the T is shaped pretty well to the contour of the prop.

I did use another level to level the prop each I rotated the prop but after a conversation with Sensenich the tech felt the prop needed to be level but using a level each time was a bit much. I use a reference mark each rotation to get the prop in the correct spot to check the pitch angle.
Thanks all, and yes I use the vans bracket but I was thinking a lever for fine tuning is useful. Fellas any thoughts to my question on post 27? Thanks again!!
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