The Omega Engine

A company called Astron Aerospace is touting their “revolutionary engine” which they’re developing under the name “Omega” (Omega is the greek letter often used to represent angular velocity.)

I don’t know if it’s revolutionary in its technology or whether it’s just hype, but its internal parts do seem to go around and around in revolutions.

Their engine seems to operate at very high rpm and with very low vibrations, and is claimed to have a very high power-to-weight ratio:

(More explicit textual narration in the video seems to start ~@3:30 and again ~@5:00 showing the axial cross-section view)

The lower wheel in the animation is surrounded by a gap, which serves as a circular arc-shaped piston shaft through which an attached nub-like piston-head travels, going around and around.

As the nub goes around the circular arc, driven by expanding combustion gases behind it, it also pushes out in front of it exhaust gases left over from the previous combustion, which leave via an exhaust port.

The upper wheel in the animation seems to be a passive wheel that’s mainly just providing a seal for compression purposes on the power stroke. So it’s a rotating seal with a rotating gap that allows passage of the piston-head. Both wheels are linked by gears to keep these respective male & female parts of theirs in sync.

It seems to be a Rotary piston engine, although not a Wankel type, and instead having a different geometry. It has a smoother purely axisymmetric rotation which appears to produce less vibrations.

The engine then seems to be able to operate at high rpm. It starts off as an Otto cycle engine, and then seems to transition to Diesel autoignition at high enough RPM (See @3:58 in video) So its compression seems to improve as rpm gets higher.

I really like this concept, and find it to be quite elegant. Like a turbine, it’s a true rotary engine and conserves angular momentum, unlike a linear reciprocating piston engine and even the Wankel “rotary” engine. This particular engine is also self-supercharging.

But the downside of this engine is that it has to operate at very high rpm in order to achieve its superior efficiency and power-to-weight. That would mean a heavy reduction drive would be required in order to transmit its mechanical power to tires or a propeller.

However, if it was coupled with a dynamo or generator, just like in an auxiliary power unit, then its high rpm power could easily be transformed into electrical power to run an electric motor (like say an electric paramotor?)

Here are the bullet points taken from the last slide of the video, some of which I’ve highlighted in bold:

  • 35 lb engine
  • 160 horsepower
  • 170 ft-lbs torque
  • Idle 1,000 rpm
  • Redline 25k rpm
  • Air-cooled engine
  • Oil change interval 50k miles
  • Gyroscopic effects canceled
  • Controlled combustion
  • Incredible fuel efficiency
  • Unmatched power to weight
  • Reduced manufacturing cost
  • Self-supercharging capability
  • Ultra high altitude capability
  • Thermal efficiency > 60%**
  • Parasitics reduced by 70%+
  • Mechanical efficiency > 90%+
  • Skip-fire technology
  • Multi-fuel capability
  • Zero harmful emissions
  • No oil leaks
  • No poppet valves or cams
  • No piston rings
  • No apex seals
  • Better user experience
  • Lower maintenance cost
  • Lower cost of EOM
  • Aerospace
    booster systems, hybrid planes, UAVs, personal aircraft
  • Generators
    portable and municipal
  • Commercial trucking
  • Automotive
  • Agricultural
  • Marine
  • Recreational
  • Lawnmowers
  • Power tools
  • Construction
  • Commercial equipment
  • Department of Defense

There are a lot of claims here that would need to be independently validated.

But I like the basic design of the engine, and that’s what gives me confidence. I like the fact that the piston is going around and around in a circular path, instead of back-and-forth like in a linear reciprocating piston engine. That means less losses due to vibration as well the cam-shaft. If you want to make your tires or your propeller go around and around, then why shouldn’t your piston go around and around in the first place?

This piston engine is a true rotary piston engine, unlike the Wankel engine which is a fake rotary engine and does not go around and around in perfect circles.

And while the turbine which is also a true rotary engine that operates at high rpm, it produces power through continuous combustion that typically suffers from an inferior compression ratio compared to a piston engine. The piston engine with its discrete pulsed combustion can achieve a higher compression ratio and thus operates more efficiently. Also, piston engines can be started and stopped more easily than turbines, which work best when operating in a steady-state mode.

I think I will stick with electric for my small microlight :rofl: