I've seen references to testing by some Valdez STOL pilots swapping props on same aircraft and getting static thrust numbers.
Does anyone have those results or a link to those results. Flight Resources has some comparative numbers for MT 2 & 3 blade vs Hartzell. I'm curious what the c/s prop of choice is for those Valdez competitions.
thanks

No input exactly but I want to say welcome to BCP!

Welcome Cameron! You a BCP'er now?

MT Propellers will beat any CS prop that I know of. Will not corrode when on a seaplane too.

Haven't any data, just my opinion from flying Cessna and Piper singles/twins.

Welcome aboard the BCP ship mate!

cbfraser wrote:I've seen references to testing by some Valdez STOL pilots swapping props on same aircraft and getting static thrust numbers.
Does anyone have those results or a link to those results. Flight Resources has some comparative numbers for MT 2 & 3 blade vs Hartzell. I'm curious what the c/s prop of choice is for those Valdez competitions.
thanks

The vast majority of the planes competing at Valdez use fixed pitch propellers, not constant speed props.

MT makes a great prop....I've been using them for years on several different airplanes, and they do indeed pull hard.

What type airplane are you flying? You might want to look at P Ponk's web site. They have a little program that sort of replicates the effects of rpm and prop length in pull. Bear in mind that program is purely theoretical, and only suggests what's happening at STATIC.

And, Static pull is sort of an indicator, but does not in any realistic manner replicate what happens as an airplane accelerates during the takeoff run. Bear in mind that the AOA of the blades changes as the airplane accelerates, so the static pull gives you a LITTLE bit of information, but sure doesn't tell the whole story.

The Ponk program does a good job of illustrating what happens to tip speeds with changes in RPM or prop length, but I've never seen nor heard of any thing that really replicates the VERY complex and dynamic aerodynamics of a propeller as it accelerates.....

MTV

There's a turboprop class in the course I'm taking. We're still working helo perf now, but the instructor teaches both and compared a prop to a rotor the other day. Which makes sense. And we've got a really good model for vertical climb perf for a rotor. When we get to the prop class I'll let you know what comes up if you want.

CamTom12 wrote:There's a turboprop class in the course I'm taking. We're still working helo perf now, but the instructor teaches both and compared a prop to a rotor the other day. Which makes sense. And we've got a really good model for vertical climb perf for a rotor. When we get to the prop class I'll let you know what comes up if you want.

I'd sure be interested in that. It's a VERY dynamic process, even more so for a constant speed propeller. Another interesting develop recently is straight carbon fiber fixed pitch props, like those made by Catto. Those blades flex a LOT, and the further out the blade you go, the more flexible they are. Trying to predict or measure thrust with one of those would be really difficult.

Interesting problem, but frankly the best test is to bolt one on and go fly it.

MTV

Yeah, I'll let you know when I get to that phase.

I just have one word to share.... Catto...

thanks for all the replies

I got a strain gauge to get a baseline for current setup and another aircraft while we were at it:


Sea level, 15C, 80+% humidity:

IO-360 rated at 230HP at 2700RPM, McCauley "toothpick" prop 1P235 8443 (need to confirm model):
- 638 lbs @ 2350 (about 150HP)

O-540 rated at 270HP at 2700RPM, MT 205-58:
-1000 lbs @ 2700

From Flight Resources testing Aviat Husky O-360 ( I assume stock so 180HP?)

Propeller Static Thrust@ 1500msl & 80F (Anyone able to normalize HP to sealevel,std temp?)
Original Hartzell 76” 672 pounds
Hartzell 80” 784 pounds
MT 2 Blade 83” 799 pounds
MT 3 Blade 78” 815 pounds

Current plan is to go with MT 3 blade - I'll update # after install.
I'd like to hope to achieve 850 or about 33% increase but given the cost maybe I shouldn't check afterwards.

The only other hard numbers I have found are from P.Ponk site - testing 185 - so presumably 300HP, some numbers from there:

PROPELLER MODEL BLADE LENGTH POUNDS PULLED

At 2600 rpm and full power....

McCauley 2 blade 2A34C66 88" pulled 1019 pounds *

McCauley 3 blade D3A34C401 86" pulled 1183 pounds

Does anyone have any data on cruise speed advantages or disadvantages to any of the props listed above for the 0-360?