Warbird Information Exchange

I'm curious what everyone's Favorite Stearman engine / propeller combo is & why ?

Years ago, I read that the Continental 220 was popular because it had an electric start capability.

Of course, a lot of guys want the P&W 450...but they're expensive to buy, overhaul and run. Also, I've heard their cowls and props are rather dearly priced as well.

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Remember the vets, the wonderful planes they flew and their sacrifices for a future many of them did not live to see.

As far as small radials go the Continental is pretty bulletproof and still has terrific parts support. I've been flying one for over thirty years on my Stearman and have had virtually no issues with it. A few years ago I switched from a wooden Sensenich prop to a ground adjustable Ham Standard and it was like adding forty horsepower, but the various metal props all seem to have their own issues. You might try posting this over on the SRA website - it’s been discussed before and at some length.

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Defending Stearmans on WIX since Jeff started badmouthing them back in 2005.

No R-680-17 fans ?

How come these engines don’t get much love ?

If you would like an expert opinion on this topic,
PM a frequent poster here, "TheBoy".

He has helped his family rebuild, restore, and maintain them (and a host of other types as well).

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Remember the vets, the wonderful planes they flew and their sacrifices for a future many of them did not live to see.

My Stearman had an R-680 and it ran like a Swiss watch. Never any trouble.

I remember working with Joe Wischler, chief mechanic at Falcon Field in Mesa Arizona during WW II. He felt the most efficient prop on a Stearman was the forged aluminum Curtis Reed propeller, next would be the McCauley steel blade prop.

I had a Stearman with a 220 Continental and the steel-bladed prop (which needed to be inspected/overhauled at a prop shop every 100 hours). Flew great with that but a friend had a Jacobs R-755 with a 2B20 constant speed prop which was even more awesome. A 300 HP Jake would be my choice!

My dad had a Stearman with the Continental engine and McCauley steel prop. He bout it around 1970. At that time there were still plenty of engines available, new still in the box as well as props of all kinds. mThe WW II guys told me that the Jacobs was the best of the three engines. Never heard anything bad about any of the three engines. I think the Lycoming had 5 horsepower more but used more oil.Bothe the R-670 and R-680 were used in military vehicles like tanks and small ships and so there were many of them to be had.
The Jacobs was produced into the late 1950's and I've flow the Waco YMF-5D with one and they are very fine engines and the best radial, IMHO.

** Had a college professor that had worked at Lycoming, been an Army pilot and later retired from AVCO. He said that in the 1950's Lycoming started bulding non aviation engines like lawnmower engines, GPU's etc. They weren't built to the previously high standards of military aviation. As a result the overall quality at Lycoming suffered and the engines burned more oil. The loss of quality seeped into the aviation division. President Eisenhower wanted to save money and chose a twin engine Aero Commander as Air Force One. Shortly thereafter, they were coming in over the Potomac and both engines started developing problems and they barely made it back to the runway. The Air Force went back to 4 place large aircraft. Also Lycomings burn more oil than Continentals.

I've had the opportunity to play with several Stearmans with W-670's, R-755's and R-985's. It really depends on what you want out of the airplane. My favorite combination option is the R-985. I have never flown behind either of the Lycoming options (225 or 300) but I have worked a little on a 225 Lyc.

If you are going stock, I'd run a 220 Continental with a McCauley steel prop. The AD on the prop is a pain but I've never found another prop that performs as well as the McCauley. I've flow behind and in formation with Sensenich and MT wood props as well as Ham Std 5404's. The Hamilton Standard is typically smoother than a McCauley, but it won't perform as well. The MT is the better performer of the wood options.

The 275 Jacobs is a pretty sweet setup. Air Repair and Radial Engines have really refined the R-755-B2 and it is a good fit for the Stearman. It retains the stock look and does help with performance. The 2B20 is a natoriously poor performing prop, so I don't think you ever get to see the full potential of the Jacobs on a Stearman but, oh well. I'd lean towards the Jacobs if you want stock, live or operate at higher elevations and have money to spend. I personally think the conversion price of a Jacobs with the STC and all is way over priced.

I've never gotten to fly behind either of the Lycoming options. I think reason they don't get the love & admiration that the other options get is that it is a bit of a dated design and maybe not as refined as the 220 or the 450 specifically. I've been told many people that they are smooth (as they should be with 9 cylinders and a relatively small displacement) and I think they are fine engines. I'm biased, but they'll never be as reliable as a 220 or a Pratt. I've flown a bit with 300 Stearmans in a 450 and to match the speeds the 450 will burn less fuel than the Lyc airplane every time.

Like i said, the 450 is my favorite combo. It fits the airplane well and performs excellent. I love the 985 in general, but it's a perfect fit for a Stearman IMHO. You can cruise around at low power or bump it up to cruise fast, climb or do acro. You do get my cockpit wind and at the higher speeds you'll feel the controls get heavier for sure.

My general thought is all or nothing. I'd do a bone-stock 220 Stearman, or a 450 with 4-ailerons and all the mods (just keep it light). That's my two cents.

Ryan

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Ryan Pemberton
www.pembertonandsons.com