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

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.

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.

Rob,

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

Thanks again
byeBill

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?

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.

Old post but I have a question that I think has already been answered...but in my searching I can't seem to find the answer.

I have finally found one of these props that will fit my O-300-C with it's 6-bolt prop flange. They seem to be harder to find used than the 8-bolt variety.

This thread is about 170's but I am wondering if this seaplane prop can be used on an early 172 on wheels (1960 172A). The TC states seaplane use only but I recall reading about this prop installed along with an Airglas fork. I thought I had seem one or two 172's n Alaska that may have had this prop but that was quite a few years ago.

I have a 170B with an O-300D installed per the 170 Association STC. I researched this last year with the thought of installing an 80 inch prop on my plane. At the time my plane was in Alaska and I reviewed all of this with my my mechanic / IA who does the annual and another IA who happened to be in the room. They were not the least bit concerned about the "seaplane only" statement. Their concern was "has this prop and engine combination been tested and approved to work together?" It has, as per the STC. They then broke out a "ground clearance worksheet" from somewhere in a desk drawer and proceeded to review how much ground clearance was required. If it had the clearance, they would have installed the prop. Unfortunately my plane has the original early 170 gear which flexes a bit and after a few measurements they didn't feel that I would have the required ground clearance. 180 gear and / or bigger tires would probably have made it ok.

Caveat.. I'm not a mechanic and I'm just repeating what I was told.

Keith

I had one on an early 56 172 before it was converted to tail dragger. You would have to have a landis fork with an8.50 to get the required ground clearance. This would require a field approval. I know of a couple that are field approved and the one I am thinking of is about the same year as yours. I will look.

Wow thanks PAMR MX!!! Much appreciated. If I could possibly get contact info of the owners maybe I can ask for copies of their paperwork.

WWhunter wrote:Wow thanks PAMR MX!!! Much appreciated. If I could possibly get contact info of the owners maybe I can ask for copies of their paperwork.

I would also be interested in some more info. When I installed the airglas fork and 8.50s, i gained 4" of prop clearance

oops, double post