Cox .049 Model

[Javiester]

Its very common for them to run in reverse, particularly when your starting them by hand.

thanks
and what of the slack?
the crankshaft moves 1mm when you push and pull with your hand horizontally
laterally it does not have any slack

 

[CraftyPilot]

thanks
and what of the slack?
the crankshaft moves 1mm when you push and pull with your hand horizontally
laterally it does not have any slack

That is not really a problem.
They don't have ball bearings but bearing surfaces and they have some slack to allow oil in to lubricate the shaft.
If the slack makes performance go down, you could try to reduce it buy pulling the driveplate further up the crankshaft with a screw.

 

[L Edge]

That is not really a problem.
They don't have ball bearings but bearing surfaces and they have some slack to allow oil in to lubricate the shaft.
If the slack makes performance go down, you could try to reduce it buy pulling the driveplate further up the crankshaft with a screw.

Actually, if the slack is to much, you can buy a tool(at Cox site) to re-seat the ball and crankshaft to improve it's performance and reduce the sloppyness of parts. I did it to improve the RPM's since that was one of the ways to get that little extra speed when you race in competition. Just don't tap too hard to bind it it up and take out the piston and don't reverse it putting it back in.

 

[CraftyPilot]

There are Piston reset tools from Cox like L.Edge said but I think he was referring to crankshaft play, not necessarily play in the big/small end of the conrod.
There is also an assembly/disassembly tool made by cox for the cylinder, crankshaft and propdrive.

 

[TheFlyingBrit]

I forgot to mention I was planning to build a trial model with just the foam (after removing the paper), and fit a Cox 049. The plan was to coat it in varnish to protect the foam and see how it went.
I was thinking of a glider style plane with a wing mounted engine, 30 seconds worth of fuel should get it up to a reasonable height. I could then glide it down and with no ESC, lipo etc and just 2 servos with a 4.8v flight battery it would be light.