Cool! I wish I had one of those kicking around.:sneaky:

I finished drawing the lower cylinder head/valve part as far as the combustion chamber is concerned. I calculated compression ratios and I can go up to 9.13 without a domed piston. After doing some research, it seems like I could use anywhere from 7.5 to around 9, so I'll go ahead with the current design. :nod:

Here's the latest in odd engine designs.

http://www.simplicitymotorworks.com/index.html

That is REALLY cool! I assume it would still have the same problems all rotary valve engines have (they can only open and close their ports at a linear rate equal to half the angular velocity of the crankshaft), but when you're not looking for nose-bleed RPM, that works!

It looks to me like an RCV engine, but done right so the cylinder liner and piston don't rotate in relation to eachother. :nod:

What's the latest?

Oh, I'm still drawing cylinder head parts. I honestly don't get to do it as much as I would like. Racing season is quickly approaching, so that may give me the bug seriously enough to really get moving on the project.

I got to do some CAD work last night. I'm spending lots of time revising things and re-drawing stuff. It's funny when you're putting a never before done concept into actual 3D space how much stuff you hadn't thought would matter really ends up mattering alot. :weird:
I'm hoping all this preemptive revisioning will help cut down on the physical prototype revisions. Those are much more expensive!;)

Converting an OS FS40 to the car version
 

Recently I noticed that some large online vendors have OS four stroke .40 parts for the car version of that engine. Parts I have found are camshaft, valve set, valve springs and complete cylinderheads. I have thought about purchasing a used FS40 airplane version and installing the FS40 car version of a new camshaft, carburator, intake, valve setup and possible a whole cylinder head.

Does the FS40 car version respond well to the improvements that enthusiast have developed for the FS26 car version ? I read thru the thread for the FS26 for cars and some of the developments that I can recall offhand are changing to a two or three needle carburator, straight-short intake, Perry fuel pump regulator, and aircooling fan.

Thumper do you make a flywheel for the FS40 car version ? I think your straight thru cylinder head modification is awsome.

Parts for the FS26 car version are difficult to find now and the FS40 car version engine have been discontinued for several years so I don't think I will be able to find a new engine.

I've never really researched that... I seem to remember the cylinder head being different from the aircraft FS40 to the FS40S-C... When in doubt, look in the manuals and compare part numbers. They don't lie - if a certain part number is the same on both engines, it is the same part. The block is likely the same, except for the color. The crank, cam, valve springs and spring seats will be different, but other than that, I'm not sure.

I have no experience with the 40... I know the 52 and Alpha 56 responded well to a 3 needle slide carb, but I don't think a smaller displacement engine would work the same with those larger carbs. Playing the carb game is kinda like roulette. You never really know how well one is going to work until you try it, and try it with all possible fuel system setups - from no pressure to pumped/regulated. Every carb responds differently to each situation. I would start out by trying a small-bore .21 carb, or possibly a big-bore TZ-18 carb, or maybe a Traxxas 3.3 carb.

I don't currently have a flywheel for the 40. My .26 flywheel would probably be too small.. Your best bet is to have someone with a metal lathe make a steel flywheel for you that's the right size for your application. That same guy would likely have a drill press to make the clutch pin holes, and be able to press in the pins. The alternative is to adapt a .21 flywheel to fit and have a steel sleeve pressed or bolted to the outside of it to bring the overall diameter and weight up to what you need.

The head and valves are different than the airplane version. Both valves are the exhaust valve from the FS-52 which is slightly larger than the FS-40 valve. If doing the conversion, buy the whole head and valve assembly.

I've not looked inside my FS-40S-C but I have been working on a parts cross reference chart for OS engines and that's what the part numbers say.

I'm also making some headway in my four stroke engine design. I have to sit down and plot valve lift in the OS to see how the numbers are going to stack up.

I have a bunch of pics saved on my computer with OS Wankels in cars. I think most were posted on Rctech. There are a couple youtube clips out there too.

Update??!
 

I've been sick almost this whole week - crappy colds... However, it has given me plenty of time to dive back into my "Thump 8" drawings. I've attached a teaser of the intake side of the cylinder head. It is very first rough draft - for instance, I leaned back, looked at it, and thought "Why did I put the carb clamp there? It would be better on the bottom... and the exhaust port can't go straight out the front like the intake, because the carb will be in the way."

Anyway, thought you guys might like to see I'm feeling motivated again. :D

Loving your ambition, I have designed a manual Clutch for 1/8 scale buggy in alibre design, but now use sketchup and love it.

Imagine 4stroke torque and a 3rd channel clutch smashing a berm MX style to clear the double double as one big quad jump (sorry getting way to excited).

Lance!

DP, any news here?