Any reason I should get a 3 blade prop for my RV-10?

[rotoiti]

Mods: please move if you feel this belongs more in "propellers" rather than in RV-10.

Oshkosh special is upon us and I was thinking about ordering it. I was initally thinking about getting a three blade prop for my -10. After talking to Bob Turner (thanks Bob!) I don't see a reason why I should get the three blade prop.

The only advantages I see are quieter operation and 2" better ground clearance. The disadvantages - lower speed, more than 2x cost. Some people mention ramp appeal, and yes, while I like the looks of 3 blades, the looks aren't worth the price differential and lost speed.

Is there anyone here who got 3 blades? Any advice?

[Mike S]

I have a 3 blade MT, came with the project when I bought it.

Dont have any comparison to offer, as it is the only prop that has been on the plane.

One thing that is a PITA with it is removing the lower cowl.

Are you by any chance at OSH??? If so, look up AFS and talk to Rob Hickman.

[N402RH]

I recently made a 4 leg trip in my RV-10 with the Hartzell 3 Blade Prop and got a consistent 175KTAS + on all 4 legs at a weight of around 2400lbs.

Level at 7500ft and 180KTAS, this is an actual screen capture taken on a flight back from Dynon a few weeks ago.


At a fully loaded 2700 lbs it will slow down to around 165 KTAS. I have been told multiple times that it is the smoothest piston plane people have ever been in.

Rob Hickman
N402RH RV-10

[rotoiti]

Originally Posted by Mike S

Are you by any chance at OSH??? If so, look up AFS and talk to Rob Hickman.

Will be there Thursday afternoon and will try to hunt Rob down, especially that I am leaning towards AFS avionics anyway

[chazking]

Most, but not all, three blades are slower. See Whirlwind prop (Bill Koleno). Empirical results demonstrate my 3-blade AeroComposite is slightly faster than the std two blade (Vans Hartzell C/S).

Removing & replacing my RV-10 cowling with a three blade is a MAJOR PITA. My cowling is modified with a 12" longer slot to improve removal clearance over the nose gear. And, a removable eye bolt in the floor of the hangar is used to pull the tail down & relieve pressure on the nose. Even with these two capabilities cowl removal is very painful & can ding the prop edges!

BOTTOMLINE: For "cosmetic" beauty & AT BEST a marginal speed increase, the total cost (& on-going operational cost) is questionable. With a loss in speed a three blade seems very questionable.

[paul330]

Pretty much been said:

For -

Smoother
Better ground clearance
Cool looks

Against -

Cost
Couple of knots slower
Cowl removal

I've gone for the 3-blade MT.

[RV10inOz]

Rob, what is your static error?

I can get around those numbers too if I fly around ar about 75-100 ROP. Probably not the optimal fuel flow for longer term use, but hey it went fast

And I use a two blade Hartzell.

Bang for buck the one out of Vans catalogue is the best. If you want ramp appeal and such, throw money at it.

I must say Rob's RV10 is mighty sexy

[pierre smith]

Ramp appeaal, schramp appeal! I wanted speed and the Hartzell blended airfoil takes the cake. I have a couple of friends with composite three blades and they're as much as 6 knots slower, even with 300 HP to my stock 260.

Yep ,one of them made the lower air intake removable just to be able to get the cowl on and off more easily.

What's wrong with saving a lot of money on a prop that goes faster?

Makes more sense.

Best,

[vic syracuse]

Ah, the never-ending debate on 2-blade vs. 3 blade. I really don't know how you really get accurate data without changing the propeller on the same airplane and performing the tests under the same conditions.
I have a 3 blade MT, and with Van himself flying my airplane right next to the factory airplane at 8500', WOT, and 2500 RPM, they were within 1 knot of each other. I flight plan for 165 knots and routinely see that or up to 171 knots at normal power settings of WOT and 2360 RPM at cruise, with EGT's of 1400 max and FF of 13 GPH. Sure, I can run it harder and go faster, or run it slower, but this is normal use for me.
This is just a data point. There are advantages and disadvantages to each. Yes, the lower cowl is harder to get on and off. Having flown RV-10's with the metal props there are different vibration characteristics and harmonics and I can feel the difference between the 2. However, much like noise cancelling headsets working differently for different people, it is the same for the props. Some notice the difference, and others don't.
For me, and me only, I assure I don't spend the difference for looks. For my operational needs, the pros outweighed the cons.

Vic

Vic

[Greg Baron]

Note the prop diamters. Shorter means lower tip velocity, less noise, usually less vibration, and improved ground clearance.