McCauley 80/40 Operators

[cessnaford]

Cessna 170/171 (ok Aeronca etc.) Operators with a Continental 0-300 with the 80" McCauley Prop.

Do you think your prop helped you out to a large degree with takeoff performance?

I purchased a McCauley 80/40 for a 1948 C-170 with an 0-300A. I wanted to get better climb performance, and was not too conserned with the lost cruise. I have only flown it once (time and mainly weather) and am not to impressed. I need to wait for some of our southern desert strips to melt off and dry up to go test it better. I felt I broke the ground a little faster but then I didn't feel I was able to gain speed any faster before climb out (while maintaining ground affect.) I was hoping to get to 80 MPH (old cessna airspeed indicator) quicker. I don't know if I need to have the prop repitched to about 80/43 (or something around there).

So...........If you are flying a Cessna 170/171 with this prop tell me your best pitch and how you performance changed with shortfield takeoffs. What indicated airspeed do you climb out?

I am tempted after 5 or 6 hours of flying to bolt the 76/53 back on and get some cash back out of this guy.

Thanks for your knowledge.
byeBill

[hotrod150]

I owned a C170 or years & lusted after an 80" prop, but never did get one. Most of the 170 guys are running 43" pitch, not 40. 3" of pitch is worth about 100rpm in my experience.

[robw56]

I have an 80/42 on my 170 and I feel it helped the take off and climb a lot. The first takeoff I did I could immediately tell the difference in acceleration. The plane climbs a lot better now especially loaded with two people full fuel and camping gear and my dog. It is also a lot more comfortable coming out of shorter strips like buzzlatka's delta strip. I used to barely clear the trees with 2 people aboard now I don't even worry about it.

[cessnaford]

Rob,

Thank you sir. Sounds like I just need to fly it more &/or get it repitched.

Thanks again
byeBill

[robw56]

Mine was originally an 80/40 when it was new, then repitced to an 80/42 before I bought it. Maybe they didn't like it at that pitch?

[gbflyer]

Props are a funny thing. One will be great, another can be the same make, model, and pitch and can act totally different. Depends a lot on if it is new or how close to new limits it might be if overhauled.

If you've never seen a prop shop work on a prop, don't. It's not that they don't know what they are doing...quite the contrary...but it can be disturbing.