3 blade MT Prop RV10

[RV82014]

Looking for any information from guys operating their RV10 with a 3 blade prop.
i.e. Performance numbers, noise, vibration etc

[rocketman1988]

Just a note if you are looking for info on the MT prop. The MTV-12 that Van's recommends is rated at 300 HP max. If you are having an engine built that produces more than the stock 260, MT recommends using the MTV-9 which is a heavier duty hub, and is rated for around 450 hp.

I have a Barrett that is making nearly 300 HP on the dyno, the MT distributor recommended the MTV-9 and that is what I bought...just FYI

[falcon900guy]

Bob,

Did you have to get a showplanes cowl for your barrett engine? this part of the build has taken a ton of work and figuring fabrication has taken a lot of work.

kenny

[paul330]

Rumour has it that it is knot or 2 slower than the Hartzell 2 blade in the cruise. However, I wouldn't swap. It is so smoooooth...... Everyone who flies in my aeroplane comments on it.

About 10lb lighter than the Hartzell so you may need to consider your C of G.

The only downside I can think of is the lower cowl removal which is a bit of a PITA. You will have to extend the slot at the bottom and fit a removable panel.

[Carl Froehlich]

Originally Posted by paul330

Rumour has it that it is knot or 2 slower than the Hartzell 2 blade in the cruise. SNIP.

That and way more expensive than the Hartzell 2 blade prop.

Carl

[rocketman1988]

Yes, I did the showplanes cowl. Yes it is a bunch of work, however, I like the way it looks and the fiberglass fit and finish is an order of magnitude better than I have experienced with the stock fiberglass. I opted for Skybolt fasteners around the firewall and may use the hinge method along the sides. I'll figure that out in the next build session...

[falcon900guy]

we are close to being finished with ours but still have a lot to do. hopefully when the guy who is helping me gets back from OSH, he will have seen one or two so we can make sure ours is on the right path. so far have done all hinges which i let my friend talk me into, but i wish now we would have done skybolts.

[Guy Prevost]

Originally Posted by RV82014

Looking for any information from guys operating their RV10 with a 3 blade prop.
i.e. Performance numbers, noise, vibration etc

I made too many changes at once to give you very objective answers, but I've had an MT 3 blade prop on my RV-10 and now have a 2 blade Whirlwind.

I made the change because for a few reasons. None of these may be big deals to others--they were just my reasons.

1. The 3 blade prop made cowl removal without damaging something very difficult.
2. My focus is cruise efficiency--having more blades than necessary to couple the engine's power hurts my engineer's brain.
3. The wood core of MT props seems to shrink in the dry desert--every MT prop at my airport has wrinkles running spanwise down the blades from the root. We've been told not to worry about it.
4. I had a WW RV200 on the RV-8a I built and fell in love with the prop. I'm just a fan. I've had long conversations with the airfoil designer and have spent quite a bit of time with his (rather odd) book.

Now to answer your questions. I had about 12 hours on the MT prop that came on my RV-10 and about 110 hours on the Whirlwind. I made quite a few aerodynamic cleanups and added electronic ignition at the same time, so I can't offer much objective data.

Smoothness: The MT propeller was definitely smoother. As others have stated, the low inertia from the short blades and the inherent damping of the wood core make for a very smooth feel.

Climb: I could detect no difference and there were too many variables in my pre/post change data to tell a difference.

Speed: I believe the WW is faster. Again, I have too many variables. My airplane was 12 knots faster in cruise after the change, but only a portion of that can be attributed to the prop. My plane was a little rough around the edges when I bought it...

Other: I can now easily remove my lower cowl. That's very important to me. I also like the looks better, but many folks seem to like the look on 3 blades for some reason.

[rocketman1988]

Thanks for the good info. I am glad you clarified the speed difference as a 12 knot difference isn't likely between those two props if everything else was constant...which it wasn't...

Thanks!

[Dustyone]

Sorry for the tread drift,

Guy,

Would you mind sharing what you have done with "aerodynamic clean ups".
I would like to think there is more economy or speed hiding in our aircraft.

Cheers,