Takeoff and climb is definitely my number one priority. I just bought the prop today and should install it sometime next week when I get my annual done. I'll write up a report on what I think and post it here. I want to do some before and after tests to try to get some numbers on what the real differences are.

Rob,

Good catch, my prop is 8042 not 8242. My plane is centered in the breakfast on the beach (botb) image from the 2011 Valdez fly in (see my gallery). I'll try to post a few more photos on wheels and skis.
I bought the plane pretty much set up the way it is so don't have first-hand experience without the mods. I am curious to see what numbers you gather with your before and after tests. You will lose some cruise but I think you will like the shorter takeoff and improved climb.

Bill

gbflyer wrote:

robw56 wrote:I wasn't aware that they had an STC for an MT propeller on a 170... unless it has an O-360.

I suspect it's not a STC.

When I had my PA-11, I became familiar with the TCDS for that aircraft. It allows for a wood prop, up to 78" in diameter if I recall correctly. It made no mention of a manufacturer, only wood, thus making the MT legal as it is wood. Although I haven't looked, I'd wager there's something along the same lines in the TCDS for the C170. They left a lot of gray areas in places when those old airplanes were certified.

The price on the fixed MT was within a couple of hundred bucks of a fixed Sensenich for the PA-11. I didn't buy the MT only because I found out about it after I bought a brand - new McCauley.

The Flight Resource guys that sell MT are very helpful. Also, I believe that Dominion in ANC is now a dealer.

gb

GB-

Now that you say it, I believe that's what the sales rep said to me as well.

Vick wrote:Any durability issues with the MTs? They were all the rage in the Stearman crowd for a while but guys discovered that they didn't hold up well operating off of turf. Different construction method for this application?

Vick-

The other part of the sales pitch was that dings are field-repairable with common materials- bondo or suerglue or JB Weld, or something like that.

denalipilot wrote:

gbflyer wrote:

robw56 wrote:I wasn't aware that they had an STC for an MT propeller on a 170... unless it has an O-360.

I suspect it's not a STC.

When I had my PA-11, I became familiar with the TCDS for that aircraft. It allows for a wood prop, up to 78" in diameter if I recall correctly. It made no mention of a manufacturer, only wood, thus making the MT legal as it is wood. Although I haven't looked, I'd wager there's something along the same lines in the TCDS for the C170. They left a lot of gray areas in places when those old airplanes were certified.

The price on the fixed MT was within a couple of hundred bucks of a fixed Sensenich for the PA-11. I didn't buy the MT only because I found out about it after I bought a brand - new McCauley.

The Flight Resource guys that sell MT are very helpful. Also, I believe that Dominion in ANC is now a dealer.

gb

GB-

Now that you say it, I believe that's what the sales rep said to me as well.

Vick wrote:Any durability issues with the MTs? They were all the rage in the Stearman crowd for a while but guys discovered that they didn't hold up well operating off of turf. Different construction method for this application?

Vick-

The other part of the sales pitch was that dings are field-repairable with common materials- bondo or suerglue or JB Weld, or something like that.

The TCDS for the 170 allows for "any other fixed-pitch wood" propeller however it must be between 71.5 and 74 inch in diameter, have a static rpm between 2220 and 2320, and be installed on a dampened crank. Most 170s these days have had dampened crankshafts installed sometime in the past if they had the C-145 variant that did not come stock that way.

What diameter is the MT prop designed for the 170? I'm under the impression that to get equal or better performance to an aluminum prop the MT is usually of greater diameter than the prop they are replacing? (I could be wrong.)

Rob,

So didja change the prop? Any numerical comparison or observations to post? We are all waiting for news.

Bill

The Prop has not showed up yet or has Rob and stacey with the 170.
I hope they shipped out Prop quickley last monday from Texas.

BeeMan wrote:Rob,

So didja change the prop? Any numerical comparison or observations to post? We are all waiting for news.

Bill

Hopefully by the end of the week. Taking off in the morning to head to Washington, getting the annual done at my Dad's.

Well I got the new prop bolted on yesterday and did a before and after flight test. So here are the half-ass numbers I tried to gather. The field I was flying out of is 297msl, it was about 65 degrees outside, the runway surface was wet grass, and the takeoff weight was about 1725lbs. I did 2 takeoffs with the old 7653 using 20 degrees of flaps into a 5 to 10 mph quartering headwind. The first takeoff was 475' and the second was 428'. I did a Vy climb up to 1900msl and it took 2:43 from brake release on the ground. I couldn't go any higher because I was underneath Portland's class C airspace, it would have been nice to do this test up to 5000' or so. After we bolted on the 8042 static RPM went up to 2400, it was about 2250 with the old prop. I did 2 more takeoffs using the same method as before although the winds had kind of died down and actually changed to more of a slight tail wind I was off the ground a little quicker at 409'. I know I can do better than that though. On climb out I saw up to 1500fpm at times. My Vy climb up to 1900msl went down 33 seconds to 2:10. I also did a 4 way cruise speed check with the GPS before and after. At 2550rpm my cruise speed went down from 120mph to 108mph. Overall I'm pretty happy with the 8042 you can really feel the plane accelerating and climbing better than before, it also runs a little smoother than the old prop.

Rob,

Thanks for the update. I am sure you will enjoy the new prop as long as you don't miss the lost cruise speed too much. A couple thoughts tho. My max static RPM is 2,330 per the prop paperwork; if that is true of your prop you might want to check your tach to see if it is accurate and then have the prop shop tweak it to 8043. BTW, paperwork says max continuous (i.e., after 5 minutes) is 2,565 rep (109hp). Also, you will have noticed that the blades are thin and can't tolerate much erosion (or filing of nicks). I have better prop clearance than typical with 180 gear legs and big tires but I am still careful to gradually add power if I am taking off on dry surfaces where the prop is apt to start moving particles.

Bill

edited to correct max static rpm and add max continuous after checking airplane flight manual supplement

I think the 2330 max static is for the 1A170 series prop not the 1A175DM8042 like I have, I've heard of people getting 2650 static rpm with that. I'm sure each tach is different though. I need to get a digital tach to check things a little better.

I let my dad fly the plane around the pattern a few times today. He did a couple 20 degree flap takeoffs and held the yoke all the way back and got the plane off the ground in 340'. I think with bigger tires and getting more angle of attack it will only get better.