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Engine and Propellor Combination...

Lefty37

Member
I'm down to three combinations that fit my imagination for my project (-7 Slider, taildragger). I was wondering if anyone had any thought's or ideas on which combo may be the best option.

1) Lycoming Thunderbolt YIO-360-M1B (180HP Parallel Valve) with a Hartzell Constant Speed Propellor

2) Lycoming Experimental YIO-360-A1B6* (200HP Angle Valve) with a Sensenich Three Blade Composite Ground Adjustable Propellor

3)*Lycoming Experimental YIO-390-A3B6* (210HP Angle Valve) with a Sensenich Three Blade Composite Ground Adjustable Propellor

The mission I'm building for is a fun sport plane to fly locally, occasionally accomplishing light aerobatics. I'm not too heavy (200lbs), and would fly occasionally with passengers who weigh less. So I think I may retain a good useful load with any combination. But I'd like the plane to maintain an adequate cross country capability too. Any thoughts? Thanks!
 
Parallel valve and CS prop. Most people I know with a ground adjustable prop never adjust it. They found a happy compromise position and that's where it stays 99% of it's life. I would save the weight on the motor and go with the CS for sure.
 
How about the IO-360 180hp parallel valve choice with a fixed pitch 3 blade.... ?

Catto built me a 3 blade prop with a pitch of 78" - climbs like a banshee and hauls the mail!

Lightweight and simple. Just sayin'
 
I have a carbureted O360 with constant speed prop, 165KTAS in cruise. I have had an airplane with ground adjustable prop and agree that once it's set you will not want to change it. Issues with setting it for a specific max RPM, then RPM in cruise, etc.. Not worth the hassle.
 
Another option- Titan (Continental) IO-370, 200+HP, Hartzell.
(lower weight with almost 390 power)
 
M1B & VP

I spent eleven happy years with a 180HP M1B with a fixed-pitch prop (happened to be a metal Sensenich) on my '7. Then I put a Hartzell VP prop on and it was as if I had discovered a new aircraft. Such a difference. I know lots of people claim that there's not much performance lost with a FP prop (that's what you're getting with a Ground Adjustable prop btw), and in a way they're right - the performance of a FP-propped RV is outstanding. But with a VP prop, the performance is simply exceptional.

I intend to build at least two more RVs and will never consider anything other than a VP prop. The relative cost difference is negligible in comparison to the smile per mile increase.

Then there's the power:weight and speed increase discussion. Sure, for bragging rights get the biggest engine. But for total performance, go with the best power you can get with the Parallel Valve engine (M1B, I think) and VP prop. You could get even better performance with a composite-based prop, but that will come at a price.

Just my 5c. Good luck your build - whatever you choose I am sure you'll be delighted.

DKS
 
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