Hi all, Long time reader second post. Need help or some oppinions. I have a MXT-7-180A with the O-360-c4F and a Sensenich 76" 56 pitch prop. I am looking for a little more performance on climb out. Static run up full throttle is 2450-2475 rpm. On take off full throttle the same #'s until the plane breaks ground then I get 2500 rpm's Vy or Vx all the way through climb out. I have been told re-pitch to a 54 pitch will help climb out and not lose a lot in cruise. All help would be appreciated. Thanks.

I would talk to a prop-shop, they can tell you your prop and/or engine pitch limits and also tell you the degree change versus rpm gain or loss.

Thanks Jeremy, I will talk to them today ( Prop shop ), I was hoping to get some opinions from guys that have done this. The runway where I am based is 3000 ft. with mountains both ends. I would like to have a little better climb performance without killing my cruise speed to bad. Wish I had a constant speed prop. Thanks for the reply and I will talk to the prop guys today and see what they can tell me.

I would suggest get rid of the sensenich.... I installed a McCauley 1A200DFA 82"/44" pitch on mine and what a different airplane. Wup at bushwheels did same prop, not sure what pitch he uses for wheels as 44" does sacrifice some airspeed in cruz. There are several other 1A200's, which is basically a Scout prop, installed on the C4F on field approvals throughout the country.

Thank's Jim, when you went to the IA200, you said it was a different plane. You mean in climb out, and how much did you sac. in cruise.

Take off roll, Climb performance, etc, etc, especially when gross weight high tremendously improved. I'm not sure what cruz speed would be with original tires, etc as I'm running bushwheels which are almost as draggy as floats, but on wheels I cruz about 105-110 MPH indicated, floats about 100-105 indicated. Under conditions on floats with the sensenich that were somewhat marginal are now a peice of cake with the added thrust. Like I mentioned, I'm at 44" pitch which is pretty fine pitch, and the prop is available in most any pitch you'd want.... I'd suggest maybe around 48" to 50" pitch if you want to keep the cruz speed up. Statically I pull about 2300 RPM and at Vx / Vy about 2500 RPM, and cruz 2350-2400 RPM. It's been my experience that a 2" repitch will make little to no difference on the sensenich, maybe get you a slight increase in RPM, but little change in ROC or cruz? There's no substitute for the added prop length on the McCauley! It might be worth some input from WUP at Alaska bushwheels to see if he's experimented any with different pitches on the McCauley as I think most if not all of his flying on wheels?

Thanks Jim, Very interested in all the input I can get. 1 question, you said you are getting about 2300 on static run up. I think on mine, or doesn't the T/C say 2400-2500 on static run up. Also you are not much different in cruise than I am. 115 mph at 2450 rpm's, 3000 ft msl. I really like the sound of good climb at gross. Thamks.

The TC Static RPM limits are applicable to the Sensenich prop. Even though the McCauley pulls less RPM Statically, it is still putting out more thrust. With the field approval for the McCauley, the TC Static RPM on Sensenich goes away... There is no substitute for length, up to a point, on the prop airfoil.... Good luck in your endeavers!!

Reviving this thread as I'm in a similar situation, trying to get more climb performance on my MX7-180A with the fixed-pitch Sensenich and the C4F engine, but less worried about the impact on cruise performance.

The easiest and cheapest option is clearly a repitch. What would be a true climb pitch and what would be the tradeoff between climb and cruise?

Also wondering how one would proceed if going the route of the McCauley 1A200DFA 82"/44" mentioned above? I'm expecting extended landing gear or large tires would be required to accommodate the longer prop? What would reasonably be the minimum setup?

You need at least 9" from the prop tip to the ground but I would go for more if you intend to land on weeds or tall grass. I would go with 12" instead of 9". That will dictate the tundra tire size. You'll need to raise the tail when measuring the distance with your current prop and tires, of course, or you can do some trigonometry by measuring the nose-up angle and calculating the length of the side between the prop tip and the ground if the tail was raised. It's usually 5 - 10 degrees depending on main wheel size and tail wheel size. Don't forget to factor in the tire compression due to the weight of the airplane and tire pressure. Tundra tires at low pressure compress more than standard tires. The most popular Maule bush wheel arrangement is with the extended HD main gear legs and 31" tundra tires. There are other Maules out there with that combination and prop so it should work. I don't know about smaller tires. Jeremy might know.

Sensenich STC'd their composite ground adjustable prop for super cubs last winter. I have been trying to convince them to work on an STC for the Maule. The more people that contact them about an STC, the better the chances they will pursue one.

Thanks @andy for the info. Seems like a costly setup, but definitely interesting.

@montana maule, that is also really interesting: a ground adjustable prop would be perfect. I'll definitely contact Sensenich to let them know there's interest there. In an article about the Cub STC it is mentioned that the weight of the composite prop is 21lbs vs. 44lbs for the metal prop. Could it make the CG move far enough aft for it to be annoying?

The equipment list shows my prop ( fixed pitch) at 36.3 lbs. If the composite weights 21 lbs. that is a 15.3 lbs. difference at - 60.5 in. It ends up moving my empty weight C.G. from 13.53 in. to 14.17 in. Not a deal breaker but it is something to consider.