powerchute50

Does anyone have any info about on board electric starting for glow/gas engines. I have seen a few of these, very neat. I can see hooking up a cheap electric can motor to the back of an engine, but the question is whether you need a bendix to engage the electric to the gas motor. Just belting them together at a high reduction ratio would be easy, but then the electric motor would be spun at high speed by the gas engine (onboard generator?). The inboard end of my gas engine crank has a threaded portion on it so it would be easy to put a gear or pulley on it.

Where would you find plans or info for a bendix type engagement? How do the turbojet starters work?

Thanks

Don

rctrax

There are units available. They use an overrunning clutch to let the starter motor cone to a stop when the motor is running.

powerchute50

Any idea where I would go for info on such a unit?

Thanks

Don

The Ghost

Try doing a search at TowerHobbies for FEMA starters.

Cheers.

the-plumber

http://www.hobby-lobby.com/fema.htm

powerchute50

Thanks for the link info. On the Hobby Lobby unit I assume there is an over running clutch or dog setup in the gear reducer unit on the motor itself? The gas engine end of the drive shaft ends in a small gear that looks to be permanently running against the bigger gear on the prop hub. The over running clutch setup is the part I am interested in. Has anyone actually seen one of these units? How does this clutch work?

Don

The Ghost

Don,
They use a one way bearing in the final gear or conection on the engine.

Cheers.

powerchute50

How does a one way bearing work? Spring loaded dogs like a pull starter? Or something flexible that only catches one way?

Don

the-plumber

Dunno if the FEMA starters use 'em or not, but [link=http://www.timken.com/industries/torrington/products/needle/drawncuproller.asp]here's[/link] a description of a Torrington clutch, used as part of the spring starters on Quadra and Zenoah engines.

powerchute50

Thanks for the link. These bearing units look like they would be the solution to my starter plans. Now I have to think of a way to house the bearing on a shaft that connects the threaded end of my crankshaft to a pulley and belt. Run this to the electric motor with a healty reduction and I should have a starter.

Time to start scratching the head and make some drawings.

Don