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  #11  
Old 12-10-2007, 08:40 PM
BlakeB BlakeB is offline
 
Join Date: Jul 2007
Location: Lafayette, La
Posts: 122
Default Thanks

Thanks for all the information. How much am I looking at converting my engine and prop to CS? Just Curious.

Thanks,

Blake
RV8
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  #12  
Old 12-14-2007, 02:52 PM
breister breister is offline
 
Join Date: Dec 2006
Location: Atlanta, GA
Posts: 1,231
Default

It depends on your engine.

If your prop flange already supports a C/S prop, you can just add a prop and a governor. Vans has great deals on props, so you could probably do it under $10k. If your engine is not designed for a C/S prop, you have two options:
a) Swap engines
b) Get an MT or Sensenich Electric prop.

The MTs are not typically as fast in cruise as a hydraulic Hartzell, although the difference is noticed more in something like a Lancair than an RV.
On the plus side, the MT is typically much lighter than the hydraulic solution, perhaps even as light as your fixed prop (which would eliminate recalculating all of your CG stuff). I don't have much information on the Sensenich, but you can get them through Eggenfellner.

Anyway, assuming an MT you will probably be in the $12-13 range for prop and controller, depending on the difference between the dollar and Euro. The Eggenfellner is $9 or $10k (3 or 4 blade) for the prop and another $1k for the controller.
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  #13  
Old 12-17-2007, 02:45 PM
Ron Lee's Avatar
Ron Lee Ron Lee is offline
 
Join Date: Jun 2005
Posts: 3,275
Default FP prop

I had a Aymar - Demuth then switched to a 3 blade Catto on a O-360 (8.5:1 pistons) RV-6A. I got fine climb performance out of my airport at 6700' MSL and even out of Leadville at 12000' Density Altitude.

When I rebuilt my engine I went to 9.5:1 pistons and have noticed a shorter take-off roll.

RPM at liftoff is in the 2200-2300 range. That does result in lower climb performance compared to a CS prop but I have never justified the cost to convert to CS since most of my time is in cruise (yes CS helps there too).
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  #14  
Old 12-17-2007, 03:19 PM
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Mel Mel is offline
 
Join Date: Mar 2005
Location: Dallas area
Posts: 10,768
Default Not Necessarily!

Quote:
Originally Posted by breister View Post
It depends on your engine.

If your prop flange already supports a C/S prop, you can just add a prop and a governor.
The crankcase and front bearing must also be compatible. There are a lot of engines with hollow cranks that still cannot run a hydraulic prop.
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Mel Asberry, DAR since the last century.
EAA Flight Advisor/Tech Counselor, Friend of the RV-1
Recipient of Tony Bingelis Award and Wright Brothers Master Pilot Award
USAF Vet, High School E-LSA Project Mentor.
RV-6 Flying since 1993 (sold)
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  #15  
Old 12-17-2007, 04:02 PM
c177tx c177tx is offline
 
Join Date: Nov 2006
Location: Austin
Posts: 130
Default slugish climb in a 180hp -8 FP?

I would suggest a cheap fix to this problem would be for you to go rent a Cherokee 140, load it to full gross weight, then take a trip on a hot day. Then when you jump back in to your -8 you should no longer have that sluggish feeling. Of course just do not go out and fly a Rocket, or the sluggish feeling will return to the -8.
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Austin, Texas
177 Cardinal
-8 empennage finished
on hold for the wing order
http://rv8-n486ap.blogspot.com/

Last edited by c177tx : 12-18-2007 at 11:27 AM.
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  #16  
Old 12-18-2007, 09:37 AM
breister breister is offline
 
Join Date: Dec 2006
Location: Atlanta, GA
Posts: 1,231
Default

Quote:
Originally Posted by Mel View Post
The crankcase and front bearing must also be compatible. There are a lot of engines with hollow cranks that still cannot run a hydraulic prop.
Good point - I was not fully specific.

You can mount an electric on virtually any hub - all caveats apply. Also, the electric props are not nearly as responsive as the hydraulic, so you can potentially over-rev your engine if you push in the juice too fast.
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  #17  
Old 01-02-2008, 09:17 PM
BlakeB BlakeB is offline
 
Join Date: Jul 2007
Location: Lafayette, La
Posts: 122
Red face Prop Pitch

What is the typical pitch of a 3 blade catto prop on a RV with 180 hp?

Blake
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  #18  
Old 01-03-2008, 06:32 AM
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pierre smith pierre smith is offline
 
Join Date: Jan 2005
Location: Louisville, Ga
Posts: 7,840
Default Ours..

....is 76", Blake but we asked for max cruise speed. Craig told us that it would turn around 2200 on initial takeoff and it does exactly that. If you'll try climbs at 140-150 MPH, you'll be surprised at the climb rate since you'll be generating more RPM, more power and so on. Even as high as 160 MPH will climb near 1000 FPM.

Regards,
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Pierre Smith
RV-10, 510 TT
RV6A (Sojourner) 180 HP, Catto 3 Bl (502Hrs), gone...and already missed
Air Tractor AT 502B PT 6-15 Sold
Air Tractor 402 PT-6-20 Sold
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