Four .049 engine powered tether racer?

For the life of me I can't find a good example... I've seen many pinewood derby cars done like that.

Thanks Travis, staggered is a good idea. and your right about if one engine runs slower or worse yet stop. it might not work with out a free wheel clutch of some sort on each wheel? oh well back to the think tank.

Get four of those toothed belts like they use in printers and such, four pulleys that will fit the engines, and two small ones that will fit a lay shaft.  

Put the lay shaft in the middle of the car, with some idlers so that a belt between the two wheels on one side will wrap.  The belt on each side keeps those two engines at the same speed, and the lay shaft syncs the two sides.

Too complicated? I agree.

How's about a four engined prop-rod.  Two tractors and two pushers maybe?   Maybe four tractors all in tandem with alternating right and left hand props so the swirl in the propwash mostly cancles.

This reminds me of Tractor pulls! This could be interesting if you find a way to work out the kinks. This may be over complicated as well but I wonder if you engage all the engines to a central grear (or pully if you want to use belts). Then you gear or belt that to an rc car differential & axil ? Sounds more complacated than it would be and the parts would be available within the hobby realm easily.

Having independent clutches for each engine/drive-wheel would be key.. but that would also require recoil-starters on each engine. Although the reed-valve engine will run in either direction.. the recoil-starters may be an issue. I don't know if they're reversible. If one of the engines shut's down inadvertently; you'd want that drive to free-wheel, so as not to cause drag on the other drives. It would certainly be an undertaking..

I have no idea of it.

Good luck getting them all started at the same time.

In the same direction!

Now you've got the wheels turning in my brain Being that it would be direct drive starting should not be a problem. Use onboard batteries to light the glow plugs, test run each engine then kill it. Maybe let the outer engines run a little slower than the inboard engines. When ready give the car a push start to get all the engines running in the right direction and watch out!!! You could play with tire diameters which would help to keep the tether line tight.

Another design that would work would be a streamliner configuration.  Each tire driven would be on a common centerline, just like an inline skate. The tether line would keep the car upright.  You could use as many engines as you want!! Try using radio control tires that balloon at high revs, if one engine slows or stops running the tire would balloon less and not touch the running surface. Just some crazy thinking

Hi unclemoon
I looked at direct drive for a tether car I’m building (slowly, very slowly) but put it the too hard basket and took the easy way out by putting the engines on outriggers with props . I like where your mind is going with this and look forward to its development and the overcoming of problems that arise .
One way of possibly overcoming the starting issue is how about a belt sander or similar concept device. If the wheelbase is narrow enough to get all four wheels on the belt then you should be able to start all four engines in the right rotation at the same time. Not too coarse a grit and a good firm contact before hitting the button should do the trick. Too light a contact could result in some very nasty flats on the tyres.

If you go with the streamliner configuration it should work just as well. With the wheels in a line and the engines staggered, two facing left, two facing right would keep the balance even and the engines gyroscopically neutral. Can anything be gyroscopically neutral, is that even a proper word. Blowed if I know but it sure sounds technical. Might try to work that into the conversation at lunch tomorrow.
Anyway, good luck with the project

The original post is over three years old so it looks as if the concept wasn't followed up.

Well so it is. I never noticed that. Oh well maybe someone will pick up the ball and run with it.........

You know it wouldn't be that hard.
Piece of U channel, say 1.5mm thick, wide enough so that with two motors mounted either side facing inwards the wheels were dead inline of the channel. Cut slots in the bottom of the channel for the wheels to poke through. Floor of the channel ideal for mounting fuel tank, sides of the channel for mounting streamlined shell, plenty of places to fix a tether arm to.
I reckon it would work Rod. Stick four cox conquests in it. That'd make it haul butt