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  #1  
Old 03-12-2019, 03:10 PM
bizpilot bizpilot is offline
 
Join Date: Sep 2015
Location: Falmouth Airpark, Mass (Cape Cod area)
Posts: 28
Default Ground adjustable prop vs C/S

Hi all, pre planning to build a RV7A, wondering what pros and cons are between ground adjustable and constant speed propellers?
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  #2  
Old 03-12-2019, 05:59 PM
rv7charlie rv7charlie is offline
 
Join Date: May 2006
Location: Pocahontas MS
Posts: 3,863
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Money, weight, climb performance/top speed trade-off required or not required.
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  #3  
Old 03-12-2019, 08:30 PM
Jpm757 Jpm757 is offline
 
Join Date: May 2013
Location: Sherman, CT
Posts: 400
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Considerable cost difference. A constant speed speaks for itself, a ground adjustable will allow you to "tune" the prop to suit your mission profile and after some experimation will find the pitch that gives you the best compromise. In the end you will still have a fixed pitch propeller. It is NOT something that you will routinley adjust prior any given flight, they can also be finnickey in getting blade angles adjusted just right. I think the 320/360 series Lyc's are better suited for a pure fixed pitch or C/S props, however Sensenich does have a G/A prop specifically designed for the RV series ($3500), I am curious if anybody has any pireps on that installation.
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Last edited by Jpm757 : 03-13-2019 at 09:02 AM. Reason: Sp
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  #4  
Old 03-13-2019, 10:42 AM
Canadian_JOY Canadian_JOY is offline
 
Join Date: Aug 2007
Location: Ontario, Canada
Posts: 2,042
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"I think the 320/360 series Lyc's are better suited for a pure fixed pitch or C/S props, however Sensenich does have a G/A prop specifically designed for the RV series ($3500), I am curious if anybody has any pireps on that installation."

My next door hangar neighbor has the Sensi ground adjustable prop on his RV9A and seems quite pleased with it. His previous aircraft had a constant speed prop and I don't think he misses the cost, weight and complexity of the C/S prop. I've watched him adjust the Sensi. While not easy, it's also not difficult. By contrast, my Warp Drive is considerably more difficult to adjust as it is infinitely adjustable through its range, rather than using the stop-block technique employed by Sensi.

Oh, the Sensi ground adjustable prop also looks pretty spiffy on his RV9A.
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  #5  
Old 03-14-2019, 08:41 AM
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Raymo Raymo is offline
 
Join Date: Nov 2014
Location: Richmond Hill, GA (KLHW)
Posts: 2,014
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CG is also a consideration in this choice. The Sensi GA is around 12 lbs, same as my 3 blade Catto, but I also have a 20 lb crush plate on the nose to help keep CG in range, which it does. Without the crush plate, your baggage compartment weight will be limited and I don't see how you could install a plate with the GA prop.
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  #6  
Old 03-14-2019, 09:10 AM
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Mark33 Mark33 is offline
 
Join Date: May 2010
Location: Baton Rouge, La.
Posts: 656
Default C/S VS. G/A VS. Sensenich or Catto dilemma

I was kind of in the same dilemma. I wanted to get away from the cost/weight/complexity of a C/S for my new -7 build and I really liked the looks and adjustability of the Sensenich G/A prop....but I eventually decided to go with the Catto three blade with nickel leading edges. My project is still under construction so I havenít flown the new prop yet, but I have full confidence that itíll perform as advertised. I actually have a Catto three blade on my -4 and I absolutely love it!!

Mark
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  #7  
Old 03-14-2019, 09:23 AM
EAGLE BOB EAGLE BOB is offline
 
Join Date: Apr 2007
Location: Redding, CA
Posts: 33
Default Ground Adj. Prop Option

Besides the Sensenich GA prop, there is also available the Whirlwind GA200-72 designed for RV airplanes with special attention to top end speed and cruise performance. Weight is 18 lbs. and can be used on Lycoming style 320/360 engines, with cost of 1/3 of what a typical constant prop goes for.
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  #8  
Old 03-14-2019, 04:41 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
Posts: 2,240
Default Whirlwind

Non RV-I am very happy with my Whirlwind GA prop.
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  #9  
Old 04-03-2019, 06:56 PM
Chattin35 Chattin35 is offline
 
Join Date: Jul 2014
Location: Boise, ID
Posts: 238
Default C/S prop, hands down

Going with a constant speed prop was one of, if not the, best building decisions I made and I almost didn't do it. Yeah, it hurts the pocketbook up front. But, I think you'll actually come out ahead in the long run fuel savings.

I've talked about more of the reasons to go with a C/S in other threads. But, I think putting a fixed pitch on an RV is like buying a Corvette and only driving it in 2nd gear. C/S really opens up the performance envelope and gives you a lot more flexibility.
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  #10  
Old 04-04-2019, 05:18 AM
dtw_rv6 dtw_rv6 is offline
 
Join Date: May 2008
Location: Martinsville, IN
Posts: 450
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Donít underestimate the value of a light aircraft. An RV loaded to gross weight is an albatross compared to a sub 1000lb aircraft with minimal fuel load on board. Fighter jet versus 18wheeler.
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