Two speed McCauley prop

[mtsdnmken]

I have a C-145-2H in my 1953 170B. What is the history behind the hydraulic propeller control valve and the two speed controllable propeller?
I can't seem to find any information about it. McCauley says the parts are obsolete and there doesn't seem to be any 170's with this option operational. Was this a seemingly good idea and design that went south in a hurry?

Any information would be appreciated, even if it's just to ease my curiosity.

Thanks,
Kendall

[Bruce Fenstermacher]

Kendall

As far as I know the TIC170 collective knows of only one operational McCauley 2 position prop and that is being flown by David Bengtson from Texas.

David reports that not much is known about the prop. He didn't know how rare it was till we told him. He only knew he couldn't find many people to help him with it.

He reported in 2005 that he didn't think the prop was any big deal. It is just the prop he's always had. He said the prop is probably not worth the effort but conceded perhaps the lack of information how to adjust and run the prop was the problem biggest problem.

From what I've gathered the 2 position prop may never have been offered direct from Cessna but you could buy your airplane with the engine (C-145-2H) to except it then add the prop after perchance. Apparently not many did and not much became of it.

My observation of David's prop is that the diameter is rather small and maybe that explains the so so performance David reports.

[mtsdnmken]

Bruce,
Thanks for the information. There isn't much out there. It is good to know that it's nothing to pursue. I was able to find just a couple postings about the hydraulic control valve but was unable to find a post going into depth on the entire system.

Thanks again,
Kendall

[Bruce Fenstermacher]

Kendall

I'm just telling you what I know which isn't much first hand knowledge when it comes to the operation of the prop. I only had a brief converstion with David and related his experience as I recall to that point. I think he has since fooled witht the adjustments but don't know if he is any happier with the pro.

Anyway if I had a -2h engine I'd keep an eye out for one of these props just because I could use it and most couldn't. I'd also like to get first hand knowledge how it works. But I wouldn't have much to pay for it so it would have to be a good as in next to nothing deal.

BTW if I had a -2H I'd also be looking for an Aeromatic Propellor for all the same reasons.

[lowNslow]

BTW if I had a -2H I'd also be looking for an Aeromatic Propellor for all the same reasons.

I don't know if this guy is legit but....... http://www.aeromatic.com/

[kbbell]

I bought my 1952 170B, N1676D, on Edo 2000s with the 2-speed prop in 1996. Flat pitch allowed me to jump up on the step, then once at altitude, adjusted power to 1500 rpm and shifted to cruise. It was a selling point on floats, but only worked for 3 hours.

It had a rebuild sticker from Anderson Propeller, near Chicago. I had Maxwell Propeller in Crystal, MN check it out. They said McCauley deemed them obsolete in the early 1970s and wasn't something they could overhaul.

Prop # 2B36C7D/78K-4

It had a much shorter take-off run than my MDM7649, similar to my 80x40, but cruised faster than the either.

There's a picture of it in, Vintage Airplane, April 1997, page 11.

-Bill Bellamy