Sun-Planet Engine - Finished

[vederstein]

I've finished my Sun and Planet engine. Given that I didn't know if this would even work when I started, I think it turned out ok.

Plans with 3D sold models are freely available on this website in the Plans section of the forum.

...Ved.

 

[Cogsy]

That turned out really nicely, well done. I'm a little surprised at how well the colour scheme suits it - not the sort of colours I would have thought of using for an engine but they work!

 

[vederstein]

Thank You Cogsy.

The color has a non-sensical story. My mother-in-law recently lost her husband. Her name is Connie. So (yeah it's a bit of a stretch) I've named this engine Contessa.

Son-in-law and planet gearing: Get it?

Anyway, I asked her favorite color. She said lavender. No suitable paint available. Second choice: bright red.

There ya go.

...Ved

 

[minh-thanh]

Great !
just a thought, why you don't make a IC engine like that !!?

 

[vederstein]

Great !
just a thought, why don't you make a IC engine like that !!?

Two Anwswer:

Answer Number One - The Personal Reason:

Because I tried a Webster once. Apparently I'm the only person on this earth that has tried to build a Webster and failed. I'm usually pretty good with steam engines. I have about a 50% success rate with Stirlings. I'm just intimidated to try another IC engine again given my previous bad result.

Answer Number Two - The Engineer's Reason (yes this is lengthy):

With this gearing set up, the flywheel rotates once or every strokes of the piston. That is the flywheel rotates twice the speed as of a normal engine when based on rotations per piston stroke. In an four stroke engine, you actually want the opposite.

A normal slider crank has the flywheel rotate once for every two strokes of the piston. To activate the valves on the four stroke engine, the camshaft is geared to half the flywheel speed. Therefore on this sun-planet gearing, the camshaft would need slowed to one fourth the flywheel speed.

The atkinson engine actually accomplishes the task of four stokes per flywheel revolution and therefore the cam can be run directly off the crankshaft.

It is possible to modify this sun-planet gearing to get one crankshaft rotation for every four piston strokes, but it's not entirely straightforward.

The planet gear needs to be one fourth the number of teeth as the sun gear. Therefore if the sun gear is 48 teeth, the planet gear would have 12 teeth. That's all and good, being that the gears don't have the same number of teeth, the planet gear will want to rotate on its axis. This is bad because then the connecting rod couldn't rigidly attach to the planet gear. There would be two degrees of freedom and the system wouldn't work.

The solution to this issue is to constrain the planet gear in a ring gear. This removes one degree of freedom and then the system would work.

I know that's a lot to think about. So yes, it can be done, but not without some significant redesign.

Thanks for the inquiry

...Ved.

 

[Cogsy]

She said lavender. No suitable paint available. Second choice: bright red.

A lavender engine would have been...interesting... On my screen though, your engine looks bright orange, not red at all. Still looks great though, and if I ever paint an engine orange you'll know where I got the idea.

 

[minh-thanh]

Ved !
About making an IC engine, I don't know the ratio of the gears to each other ..., just a fleeting idea: making an IC engine that looks like that will be interesting
About you having failed once with a Webster engine: For someone who has succeeded with a steam engine and especially a stirling engine, I don't think it will be difficult for you.
Please redo, You just need to focus on compression! all the rest like ignition, valve opening time, fuel ... it's not difficult
( That's the way I did with the first IC engine, with a little experience in large engines, I just needed the compression engine, with the first engine I redo the cylinder and piston many times, and damaged 3 Crankshaft only feels like the engine wants to run )
The choice is yours !
Honestly, I want you to do it again

 

[ShopShoe]

Ved,

That turned out really well. I think it IS interesting to look at both non-running and running.

Thank You for posting.

--ShopShoe

 

[JohnBDownunder]

Very interesting engine, Thanks for sharing it with us.
My screen also has the colour coming up orange and still looks good anyway, I could adjust screen to get a red but too lazy I guess???

 

[vederstein]

Hmmm... I rewatched the video and now it's orange on my screen. Trust me, in real life it's a bright red. So let's chaulk this up to being a ****** digital camera. (The camera is around 12 years old now).

...Ved.

 

[JohnBDownunder]

May not be the camera so much as the light source, that can play havoc with colour. I retired 20 years ago after a working life of messing with colour (Textile Dyer) and love being retired messing about in my playpen trying to make model engines rather than a pile of swarf.