Cox Engine of the Month -3 Way Tie Vote-Off

So it is designed to fire sequentially and has a common crankcase?
Doesn't seem particularly smart, does it run?

Thats right, I have to throw your radial page together that will load when someone clicks on the picture.





OK, I just made the page. Click on the small picture on the left and it will open a page with some info.

Surfer_kris wrote:So it is designed to fire sequentially and has a common crankcase?
Doesn't seem particularly smart, does it run?

It doesn’t seem likely to be a runner unless he has incorporated some ingenious way to create three crankcase suction/pressure cycles per rev. Not saying its impossible; just that it isn’t obvious to me .
Al

It must run!
Even I could make one that didn't run.

It would need a compressor on the intake in order to run, but it looks like it is just has a regular sure-start reed valve on it.

Surfer_kris wrote:It would need a compressor on the intake in order to run, but it looks like it is just has a regular sure-start reed valve on it.

You are correct in that it needs a compressor to run. Having 3 cylinders on one crankcase it looses its suction. Ideally it needs a roots type compressor. I am planning on modifying the rear cover to use a full length sure start crankshaft. I will have a pully on the output and it will drive a RB Innovations super charger. I have a carb off of a OS 12CZR that I am planning on using for the engine. I can then do away with the sure start backplate and make a radial mount out of aluminum. I have the supercharger and the aluminum. I just need the time.

The engine does run off the prime. I will have to get a vid of it up. The sound is amazing

Jason

Oh yes I cannot wait!

There are in principle three choices/possibilities in a multicylinder two-stroke engine; i) simultaneous firing (e.g. G-Mark .12 opposing twin), or ii) separate crankcases (e.g. G-Mark .30, 5 cyl. radial) or iii) compressor on the intake.

I can't think of any commercial 1/2A size engine with a compressor? So it seems like a bold endeavor...

Well how does valentine do it?
I don't have one of his to disassemble and look at.

I don't have any from valentine myself, but I believe each cylinder has an individual crankcase with gears that drives a center propshaft. I.e. the same design idea as the G-Mark .30 (5 cylinder radial).

Just found this info.

"Let me introduce you to the Mark I & II Taifun 3 Cylinder Radial diesel engines. The crank case was machined from bar stock and only the Mark II was sand blasted. We manufactured 10 of these engines. The cylinders and spinner were anodized in different colors. Each cylinder had 2 intake and 2 exhaust ports. All of our multi cylinder engines have divided connecting rods and a one piece crank shafts. The Mark I has a 3 piece and the Mark II has a 2 piece crank case."

Looking through Valentine's site it seems that he has made both geared and compressor types;
5-cyl radial

Still, a two stroke engine cannot have one common crankcase volume unless the cylinders fire at the same time, or the crankcase is pressurized.

Surfer_kris wrote:Looking through Valentine's site it seems that he has made both geared and compressor types;
5-cyl radial

Still, a two stroke engine cannot have one common crankcase volume unless the cylinders fire at the same time, or the crankcase is pressurized.

Yeah and i think even Valentine would struggle making a 4 stroke 5 cylinder radial of 0.098cc

With a four stroke radial you can have a common crankcase without any problems, that's is perhaps where the poor design comes from.

Yeah the designer probably did not have much experience with cox engines.