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  #1  
Old 06-09-2021, 04:45 PM
bshawco bshawco is offline
 
Join Date: May 2021
Location: Near Durango, CO
Posts: 2
Default 2 vs 3 Blade Sensenich for RV-12iS

I've been wondering about the real-world pros and cons of the 2 blade vs. 3 blade prop available from Van's for an RV-12iS. The elevation of my home field is about 6,500' MSL. I know one "con" of the 3 blade prop is cost, but I'm primarily curious about differences in climb and cruise performance. However, there may well be other considerations I haven't thought of.
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  #2  
Old 06-09-2021, 04:53 PM
Norman CYYJ Norman CYYJ is offline
 
Join Date: Feb 2005
Location: Victoria B.C.
Posts: 1,343
Default

3 blades quieter. 3 blades not as efficient, more dangerous to hand prop 3 blades. 2 blades noisier, 2 blades cheaper. 2 blades more purchase options.
,
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  #3  
Old 06-09-2021, 08:46 PM
RFSchaller RFSchaller is offline
 
Join Date: Oct 2010
Location: Phoenix, AZ
Posts: 3,072
Default

Norm,

You forgot the “cool factor” of three blades!😝

Rich
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  #4  
Old 06-09-2021, 09:22 PM
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TigerMan92 TigerMan92 is offline
 
Join Date: Mar 2019
Location: Ann Arbor, MI
Posts: 31
Talking 3 Blade Prop

I'm a big fan of my 3 blade MT prop. Looks cool, sounds cool and performance is fantastic with CS.
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  #5  
Old 06-10-2021, 03:59 AM
thiggins thiggins is offline
 
Join Date: Mar 2020
Location: Saluda,NC
Posts: 28
Default What Vans has to say…

https://www.vansaircraft.com/2020/02...2is-available/

https://www.vansaircraft.com/wp-cont...powerplant.pdf
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Last edited by thiggins : 06-10-2021 at 04:03 AM. Reason: References
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  #6  
Old 06-10-2021, 09:57 AM
bshawco bshawco is offline
 
Join Date: May 2021
Location: Near Durango, CO
Posts: 2
Default

Thanks all - very helpful! I never thought to search "Three-blade" instead of "3 blade" on the Van's site...
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  #7  
Old 06-10-2021, 10:25 AM
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Piper J3 Piper J3 is offline
 
Join Date: Nov 2014
Location: Hinckley, Ohio
Posts: 2,432
Default

You mention the “cool” factor for three-blades. I saw the three-blade prop at Van’s both two years ago at KOSH. I thought it really looked bad. Blades are smaller cord to disperse same fixed HP. The two-blade prop with scimitar sweeping shape is eye candy in my opinion.

If you really want multiple-blades I saw this at local airport last year…
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Jim Stricker - EAA #499867
PPL/ASEL 1970 - Sport Pilot since 2007
80 hrs Flying Aeronca Chief 11AC N86203
1130 hrs Flying 46 Piper J-3 Cub N6841H
Bought Flying RV-12 #120058 Oct 2015 with 48TT - Hobbs now 670

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Special Thanks... EJ Trucks - USN Crew Chief A-4 Skyhawk
MJ Stricker (Father & CFI) - USAAF 1st Lt. Captain B-17H
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  #8  
Old 06-10-2021, 11:03 AM
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pstraub pstraub is offline
 
Join Date: Nov 2015
Location: Hensley Airpark, TN
Posts: 159
Default

I have had my 3-blade installed for over a year now and I love it. For performance, I can't say I noticed any difference one way or the other. It is smoother for sure and I am a fan of the 3-blade look. You can remove the entire prop as one piece without disturbing any of the blade angle adjustments. To me, that's a major advantage over the 2-blade.

Now the bad news.....I never considered that I would be adding a great degree of difficulty in removing my lower cowling. It went from trivial (with the 2-blade) to very frustrating/difficult with the 3-blade. There is just no way to position the prop, at least one blade is always in the way. If anyone knows a slick method, PLEASE let me know!!
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  #9  
Old 06-10-2021, 12:07 PM
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Tony_T Tony_T is offline
 
Join Date: Dec 2008
Location: Lacey, WA
Posts: 1,411
Default Cowl Removal with 3-blade

Paul, interesting. Looking at the hours you have on the ship (205 after 4 years), it could be that the only cowl removal you would need to do would be at annual condition inspection? Then it may be easiest to simply remove the prop. You would have to inspect it and the hardware and torque check the bolts anyway.
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  #10  
Old 06-10-2021, 03:06 PM
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Dvalcik Dvalcik is online now
 
Join Date: Jul 2011
Location: Royersford, PA
Posts: 871
Default

Quote:
Originally Posted by pstraub View Post
Now the bad news.....I never considered that I would be adding a great degree of difficulty in removing my lower cowling. It went from trivial (with the 2-blade) to very frustrating/difficult with the 3-blade. There is just no way to position the prop, at least one blade is always in the way. If anyone knows a slick method, PLEASE let me know!!
I elongated the hole where the exhaust comes out and have been able to remove it with another persons help - one on each side and drop down, twist & angle then pull forward. Still have to be careful but I has been worth it for me. I had a 3 blade Sensenich when she was built in 2012 and later put the new Sensenich on once it came out a little over a year ago.

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