Alternative Engines

Flyhound

Flyhound

Pre-takeoff checklist
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Flyhound
I'm not holding my breath, but there seems to be a great opportunity for alternative aircraft engine development. Rotax was an upstart a couple of decades ago and they innovated like crazy until their 4 stroke 912 came out. Advancements since then seem limited to design refinements (turbo, fuel injection etc.) rather than radical new offerings.

When I worked in a Naval Shipyard, we overhauled a number of hydraulic "swash plate" motors that were used as anchor windlasses, and in other applications that required maximum torque at low RPM. I always wondered why an internal combustion engine built around that basic approach hadn't come along.

Then I read about the FAA certified Dynacam engine that used a swash plate like torque converter to get rotational power from the reciprocating pistons. Despite being FAA certified and enjoying some actual use on a small plane, that engine never went into production.
https://www.youtube.com/watch?v=uJSLDq7MkhQ

Recently , a new engine design company in New Zealand has picked up on this basic concept with a compact, axial drive internal combustion engine. The introductory video is interesting.
https://www.youtube.com/watch?v=c19kn3drdFU

So, what are the chances that the Duke engine will ever see production and become available as a homebuilt engine option? What allowed Rotax to go into mass production and become the defacto power plant used for LSA? How did Rotax succeed while all other would be contenders have been left on the sidelines?
 
Flyhound said:
Recently , a new engine design company in New Zealand has picked up on this basic concept with a compact, axial drive internal combustion engine. The introductory video is interesting.
https://www.youtube.com/watch?v=c19kn3drdFU

So, what are the chances that the Duke engine will ever see production and become available as a homebuilt engine option? What allowed Rotax to go into mass production and become the defacto power plant used for LSA? How did Rotax succeed while all other would be contenders have been left on the sidelines?
Click to expand...
The chances for the Duke engine are about the same as every other revolutionary new concept that has come along in the last 100 years. In the end, cost, complexity, friction, and a lot of little details pretty much clobber the idea - plus issues with capital and business management. There will be problems with the sliding seals at the top of the combustion chambers, problems with the wobble plate, and who know what else.

The conventional crank / rod / poppet valve arrangement is popular because after years and years of testing alternatives, it's what works.

Rotax builds a conventional engine. Rotax aircraft engines were part of a much larger corporation making similar engines for several powersports applications. So Rotax succeeded because they had capital, engineering / manufacturing experience, and a solid business unit.
 
The only real alternatives I expect to see will be more like what Ben has in his plane (I still need to go for a flight in that thing...) and then diesels. The various "unique" engines won't go anywhere. There's a reason the traditional arrangements are still here more or less unchanged after 100 years.
 
The DeltaHawk is getting closer. A two-stroke ported diesel with allot fewer parts.
 
cgrab said:
The DeltaHawk is getting closer. A two-stroke ported diesel with allot fewer parts.
Click to expand...

Hahahaha!!

Define "closer"... they've been playing around with it for years without much result to show...
 
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