Announcing the Merc 888

[Fastjeff57]

And video, Tim, video!

Jeff

[Tim Kurcz]

And video, Tim, video!

Jeff

You betcha the will be video......

Tim

[Yellowjacket]

Hi Jeff,

By Jove, you've got it. After about 12 hours design, mockup, and re-design work, I've settled on the master-link rod concept. Now it's a tussle between pivot joint options: 1) A .375" steel pin riding in a tiny full complement drawn cup needle bearing, 2) A .500" steel pin riding on a bronze plated bore, or 3) A .500" bronze pin riding in steel bore. I'm leaning toward a 1/2" pin.....

Assuming the proof of concept actually runs, only moderate power/RPM would be used: It would be fun to drive the little beast just to see the looks on peoples faces (and get a few pics, of course). If it behaves itself, a more robust version might follow.

Tim

Go with the rolling element brg.. With a half inch pin and not much length you'll seize it in no time without full pressure lubrication (or even with full pressure lubrication). If you keep the speed down you may not have a long bearing life, but it won't seize up after a few minutes... Remember that the angular rotation is all you have to deal with and the full complement bearing can take a good bit of load.

[Tim Kurcz]

Go with the rolling element brg.. With a half inch pin and not much length you'll seize it in no time without full pressure lubrication (or even with full pressure lubrication). If you keep the speed down you may not have a long bearing life, but it won't seize up after a few minutes... Remember that the angular rotation is all you have to deal with and the full complement bearing can take a good bit of load.

Your proposal makes sense: It's the relatively small .375" pin that has be nervous. But then again, it only needs to run an hour under light power.....

[daveswaves]

Hi Dave,

Considerer that he Merc 4-cyl crank is two pairs of opposed crankpins spaced 90 degrees apart. So, two of the piston/rod combinations will actually assemble in-line (but not rotate). As you're lowering the upper block while attempting to stuff the second pair, you realize pistons are hanging way outside the blocks because the opposed rods don't swing because of the solid beam rod. Does this help?

Tim

Thanks Tim and Hydroplay, that got my brain working.

[daveswaves]

http://thekneeslider.com/the-hossack...on-two-stroke/

As long as we are talking about out of the box thinking Mr Hossack has an idea too.

[Tim Kurcz]

http://thekneeslider.com/the-hossack...on-two-stroke/

As long as we are talking about out of the box thinking Mr Hossack has an idea too.

Kinda cute; a cross between a Wankel and reciprocating two stroke.

[daveswaves]

Novel port blocking with the rocking piston.

[Techteam]

Tim what you need to get some pumping for starting is one of these



electrically driven supercharger. link that to the exhaust turbine side h
as a built in clutch so as the exhaust pressure rises the electric motor is disconnected.

[Techteam]

the nice thing about the merlin or other aero engine conrod arrangement is the master rod creates a bearing journal for the second rod.