Lose 5-10 knots with a 3 blade prop on a 10?

[rvbuilder2002]

Originally Posted by Kahuna

Vic is of course correct.

I am confused....

Vic stated that the MT three blade is about the same speed as the Hartzell 2 blade, but your test data seems to indicate otherwise.

BTW, I enjoyed seeing you on the SV Seeker episode

[Subwaybob]

Originally Posted by vic syracuse

To each their own.

BTW, we did that with my RV-10 (swapped props) and noticed no measurable difference in speed. We even took my RV-10 back to the mothership and let Van fly my airplane right next to the factory RV-10, with both Van and I in mine (Van doing the flying) and Ken Krueger flying the company RV-10. At 8500' and full throttle, we were neck and neck. The GPS's on each airplane were within 1 knot of each other. Everyone was surprised. Without swapping the props it still didn't mean anything except it put to rest all of the hullabaloo that the MT is 10 knots slower.

There are advantages and disadvantages to each prop. one might be smoother, have more ground clearance, and better climb performance. The other might be more durable on unimproved runways, easier to get cowling off, cost less, etc..

Racing is a totally different arena.

Build the airplane for you.

Vic

Vic, could it be that your plane was only 1 mph slower than Vans because you had another 50 hp under the cowl? Was your plane making 310 hp when you did this test? I would really like the MT, but.... I want you to tell me that it wasn't making that much hp so I can buy one and be quiet and cool for the same speed!

http://forums.matronics.com/download...87b704c83f7e5e

[Bavafa]

How about service and support from MT vs. Hartzell?

I have not heard any positive or negative thing about Hartzell but know of at least two unhappy people with MT, in relation to warranty/support.

They also did a poor job dealing with the prop governor issue a couple of years back.

[rocketman1988]

No, his airplane was not making 310HP during the test at 8000+' DA...but Van's wasn't making 260HP either.

As stated in the article's conclusion, the 2 bladed prop is more efficient. That is no surprise as the theoretical calculations indicate this. Problem is with two different aircraft, as the article stated. Too many different variables between the aircraft to get truly definitive data.

The only way to get better data is to fly the different props on the SAME aircraft...

[rdrcrmatt]

Last night I was seeing

174 TAS, 24.5", 2300RPM, 14gph LOP, 2700' DA, 5500' MSL, 2?F.

Thunderbolt IO-540, Hartzell c2yr-1bfp/8068d (I think that's the number, from memory)

Just a data point for you.

[Michael Henning]

Randy Leverold tested the Whirlwind two and three blade props on his RV-8. The three blade prop was two knots slower. Climb, acceleration and deceleration were all better on the three blade.

[Dbro172]

Why not have the best of both worlds and install the MT 2 blade prop like I did on my 182.

[Gusmax]

2 vs 3 blade discussion has been going on in the Mooney world since they started retrofitting 3 blades to them. The consensus is that 2 blades are faster on Mooney's. I will be putting a 200 HP Mooney engine and 2 bladed Hartzell on my F4 project.

Cheers,

Phil

[Plummit]

Originally Posted by Dbro172

Why not have the best of both worlds and install the MT 2 blade prop like I did on my 182.

Yeah but you lose any gains without the wheel pants! ;-)

-Marc

[paul330]

Originally Posted by BobTurner

Paul (and others),
I apologize for sounding harsh - that was not my intent. But please re-read your own post. ?The winner was 5 knots faster for unknown reasons?. If the winner had chosen to run a brand X prop, lost 5 knots and run even with everyone else, would the correct conclusion be that brand X was just as good? You need to vary the prop, and only the prop (same airframe, wx, etc) to reach a supportable conclusion.

No offence taken Bob ........

I didn't get a chance to check out the prop on the faster -10. Could be he had some fancy Scimitar, blended etc etc. As I said, I would love to borrow a 2-blade and see what it could do but it would be a huge amount of work to try and prove a point - and I certainly can't justify spending $10k just so I can get an extra couple of knots in a once-a-year air race - especially as my wife isn't complaining about me building a Bearhawk

In my opinion, the MT 3-blade is an excellent prop. Super smooth and great looking. I get 155kts TAS (178mph) at 9000', 60%, 10.5 usg/hr - that'll do me .........