Poor flow, nonexistent combustion swirl, incomplete fuel burn, high polluting, low compression, horribly inefficient...

I could go on, there are valid reasons most all modern reciprocating engines (even your lawn mower!!) have gone from side valve to overhead valve designs. With the rated power coming at 2930 rpm, the low rpm argument doesn't hold water, either.

This might be something to watch over the next few years. Still a piston /crank engine but with a yoke attached to lengthen the effective throw of the crank. It gives the power stroke more leverage on the crank at the instant of combustion. It more than doubles efficiency and produces extremely high torque.

http://www.fishertechnologies.net/howItWorks.php

Caution: They are looking for money.

Here's another one just popped up. Looks very interesting.


http://www.eaa.org/news/2012/2012-11-21 ... 1+ehotline

No mention of the Geo Metro/Suzuki Raven Re-Drive. Any experience there? I know of a 4 cyl turbo'd setup in a CH 701. Claims lots of power, but just finished his 40 hr test run. No long term experience yet.....

I have been impressed with this engine's possibilities for aircraft use in it's diesel or gas form. The diesel of course needs no redundancies in ignition systems. http://gas2.org/2011/02/02/opoc-engine- ... bodiesels/

In four cylinder or more configurations a coupling clutch disengages each two cylinder unit at a time when they are not needed but making power on demand and cruise more efficient.

OK how about this one? http://www.dair.co.uk/ Let's hope it doesn't have Lucas electrics.....

Emory Bored wrote:OK how about this one? http://www.dair.co.uk/ Let's hope it doesn't have Lucas electrics.....

I just noticed the dates on that website. Haha. It never happened. Two stroke diesel....Detroit Diesel.....EPA condemned.

EB

Behind, the IO-240 is fuel-injected.

I'd like to see a "shootout" of various engines on the same aircraft type and weight, to see what one is really buying with another five or twenty-five hp. Especially at 1320 gross.

Continentals & Lycomings are good.
So are properly done Corvairs. Many hundreds flying and they are very affordable compared to a Continental or Lycoming, especially at overhaul time.
William Wynne and gang have developed the Corvair into a solid dependable performer. http://www.flycorvair.net

At Airventure 2012, Rotax celebrated selling 40,000 912 series aircraft engines. How many more since then?

Rotax is still far and away the benchmark for the class. Best power to weight, longevity, fuel economy, support, compact design, ...

As far as cost is concerned, they are still very competitive with all of the others, too.

The ShootOut already happened, Rotax won, and won big.

I'd like to see some kind of bar graph showing all the engines in the 100 horse class, and broken down as to total numbers of units sold and most importantly total number of flight hours in service. Then the number of said models reaching or exceeding the stated TBO. I think it would clearly illustrate the 912's absolute dominance in a huge way, like off the chart. Broken down like that it would more clearly show what IS working and what HAS been working, as opposed to PR pipe dreams and hoped for greater reliability.

I'm not saying this dominance is a good thing, (in fact I wish I didn't like mine so much as they cost so much but I don't care) or that newer designs are no good, but man they have a long way to go before the boys in Austria have anything to worry about.

Roger that, guys. Rotax 4 strokes are good engines. Expensive too. I'll stick with my Corvair regardless...