Craig Laycocks double end piston motor.

[coaster]

What do you think about this?
Personally, i like it.

[Just_a_fan]

What is the benefit of that approach? What sort of power is it going to produce.? Presumably it'll need to rev very high as it'll be producing fairly low torque with almost no lever arm.

[Maritimer]

Wonder why bother with the herring bone gears on the crank pins when you have the inner blue member to keep everything located? Wouldnt a regular spur gear be better at high rpm?

[coaster]

He is using a spur gear, he posted this version to silence a commenting troll.
He has watered it down heaps for the public, im told a prototype is well on its way.

The rpm range was not shared, obviously it must be higher than normal.
I look forward to the running prototype.

[SiLo]

I guess it will just end up like a smaller boxer engine?

[PlatinumZealot]

Post this in the engine section. The boffins will pick it apart there.

[Rodak]

I wonder how you assemble it.

[Greg Locock]

It looks as though the pistons are split. It's a typical Solidworks engine. As a mechanism, or indeed as a slow speed pump, it might work, ie go round. But it is just a kinetic sculpture, not an engineered engine.

[tok-tokkie]

Using a gear drive should give the piston exact simple harmonic motion.
But he could follow Manolis's lead and use a connecting rod. Far simpler and less friction. Not perfect SHM but so what? But I suspect that would have been thought of long ago.

[coaster]

I suspect the big end / main bearing eccentric bush may be the achilles heel, without a thrust containment everything will rock and wobble which will worsen with wear.

[J.A.W.]

I guess it will just end up like a smaller boxer engine?

No, not a boxer, they are opposite, being 180 degrees apart in piston motion.

[J.A.W.]

I suspect the big end / main bearing eccentric bush may be the achilles heel, without a thrust containment everything will rock and wobble which will worsen with wear.

Unless its a 2-stroke, wherein thrust from the piston is always downwards to the crankshaft...

[coaster]

It might mature into a nice little engine, im afraid with this much intellectual property being revealed as the design process evolves it will slip though his grasp in terms of ownership.

He really should look at Manolis' approach, Manolis is iron clad in protecting his designs.



Craig is letting us see the designs evolution.

[Greg Locock]

JAW - except that inertial effects might easily reverse the main journal load, especially at high speed.

[63l8qrrfy6]

Bolting a presumably aluminium piston running close to 300C with steel bolts through the crown is a recipe for disaster.
The gear will never work, not with normal profile deviations, bearing clearances and crank deflection. The load won't be shared evenly between the 2 sides. I'd also like to see how he plans on cutting the external teeth on the crank pin, particularly in between the webs - I don't think there is enough tool access.

Yes there aren't piston thrust loads but the friction losses in the big drum and the gear will be significantly higher compared to a normal plain bearing arrangement. Rotating and reciprocating inertias are surely higher too.

So the question is what does this design really achieve ?