Follow on: Dr. Mr Lycoming... Best engine

I really liked the comments on the last open-ended posting I made regarding high cam shaft... Here's another. I know how ubiquitous Lycomings are in the nose of an RV.

Some of the responses to my post suggest maybe this shouldn't be so defacto. So what is the best engine for reliability, fuel efficiency, specific power and maintenance on a flying platform the size of an RV?

Is there a Continental or Franklin engine which would technically fit and operate better?

Thanks!

BruceMe said:

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So what is the best engine for reliability, fuel efficiency, specific power and maintenance on a flying platform the size of an RV?

Is there a Continental or Franklin engine which would technically fit and operate better?

Thanks!

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What you are going to find out, Lycoming is tops in almost all categories if not tops in all categories. IIRC, AOPA did this study a few years back and the Lycoming beat out even the latest auto engines when it came to fuel efficiency and weight per horsepower.

I built an RV-8 with a turbocharged Mazda Rotary. It probably added 5 years to the build time.
Yes, it ran well.
It was FAR more powerful than a Lycoming.
At very low power setting it was quite fuel efficient.
It was about 30 pounds heavier than the Lycoming O-360 that replaced it.
I flew the Rotary engine for 16 hours, after which I installed a Lycoming parallel valve IVO-360A1A from a Brantly B2B helicopter. I had been so busy with engine development (exhaust & coolant leaks, Turbocharger resizing, Cooler re configuring, adding a Muffler etc, that I had not been working on the flight test card. I fell behind on evaluation of the airframe. I was just flying around the airport tuning and observing engine operations.
This Vertical Lycoming was converted to horizontal aircraft service with an accessory case and a sump.
Cut to the Chase:
Modifying an RV to take another engine is time consuming and fraught with unintended consequences. Even the Franklin conversion, which seems pretty straight forward has only been done a few times.
I don't think there is sufficient difference in the engines or their prices to justify deviation from the plans.

SHIPCHIEF said:

I built an RV-8 with a turbocharged Mazda Rotary. .

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One of my first EAA meetings was at Crest. Did you have a Mazda powered RV-4 there? I really miss Crest. Learned to tail wheel with that crazy mechanic in his Champ.

Bruce;
Yes, I flew my RV-8 with Mazda turbo rotary out of Crest, in December of 2013, and into 2014.
Glen Peterson was giving tail wheel instruction in his Champ, I probably watched you!
Although I have been a member of the Crest Airpark EAA chapter, I am currently a member of the Puyallup EAA 326 chapter, very RV oriented, an an inspiration that helped me complete my bird.
(Sorry about the thread drift!)

The airframe is designed with a Lycoming engine in mind. That makes it pretty hard to find a more suitable engine than the one that was designed to be there.

Many people have been successful developing engineering solutions to use different engines. The common theme is it takes much more development on the part of the builder to adapt the engine and airframe together. In the long run, it doesn't offer any real advantages. Performance and economy end up being relatively comparable.

A Ford engine might be fantastic, but it won't work very well in a Chevy.

FWIW, I used to own half interest in a Globe Swift (initially with an IO320, later with an IO360/200 Lyc). Swifts have had just about every aviation engine available installed on them. The one that most Swifters love the most is the Continental IO-360. You'll see weights listed all over the map, for both Lyc & Cont engines, largely due to variations in intake systems accessories, etc. But contrary to popular belief, the 6cyl Cont is roughly the same weight (in some cases, lighter) as the angle valve Lyc. The downside is a typically 1500 hr tbo (rating) and the extra expense of 2 extra cylinders. The upside is...smooooth operation. And with a 6>1 header style exhaust, the sound is, well, almost sexual. Nothing at all like a farm tractor.....

Installation/development on an RV airframe would be a bit of an adventure, however. They use a bed style motor mount, and the standard injection system requires a return line. It wouldn't be as involved as a water cooled alt engine, but still much more work than the 'aluminum IKEA' that RV assemblers have come to expect.

Again, FWIW,

Charlie
Mazda Renesis FWF in progress, RV-7

Doesn't the 2nd prototype RV-10 have an IO-360 Conti installed? Might be able to leverage what Van's learned in the installation process if someone wanted to go down that alley (I mean for installation in something besides a -10).