Start engine with drill

[gbravo]

I have read in some posts that the drill is not good for start engines. Why?
German

 

[stevehuckss396]

I have seen many modelers at the shows using battery drills to start engines. They seem to work fine. I use a modified RC type starter. RC starters work real good also.

 

[JohnS]

One way that I have found successful is with the use of a one-way needle bearing fitted into a holder and chucked up in a vari speed hand drill. A quick search on eBay will soon find a supplier of these bearings. I use such a device on Jan Ridders simple two stroke and it works fine.

I owe the idea to Bogs and if anyone would like further info on this little gizmo then just let me know.

John-Som

 

[dparker]

GBRAVO:
Interesting question. I have seen a fellow that built a couple of locomotives and gave my daughter and her cousins rides on one. He was a WWII machinist and did really nice work. To show me his last engine he tried to start a small, high compression diesel model with his 1/2" drill, it kicked back and stripped all the gears in the front end of the drillmotor, I remember it well, made a big impression on me as to the cost of replacing the drill motor--felt bad for the fellow.
When I built my IC engines I built a kick-out type starter socket like the old one cylinder farm engines. It will not "kick out on a backfire but will throw the drill motor back away from the motor when it starts. My IC motors have much lower compression and they are hit and miss engines so the drill must be run fairly slow or the exhaust valve stays open and they will not draw a vacuum to pull in the fuel. I believe my engines are set with a somewhat retarded timing and have not had much in the way of backfiring while trying to start them, just lucky I guess. I must admit I have seen several modelers start their engines with drill-motors at the GEARS show here in Portland, OR over several years.
Best of luck to you------don

 

[JohnS]

GBRAVO

In the event of the engine 'kicking back' or 'back firing' whilst been started the freewheel characteristic of the one way bearing prevents the force being transferred back to the drill. Forces applied in the opposite direction of intended travel simply spins the bearing in free wheel mode. I imagine the fellow who tried to start his high comp diesel applied direct force from his drill on to the crankshaft without a one way bearing, a recipe for disaster !

John-Som

 

[Admiral_dk]

John-Som :

In the event of the engine 'kicking back' or 'back firing' whilst been started the freewheel characteristic of the one way bearing prevents the force being transferred back to the drill. Forces applied in the opposite direction of intended travel simply spins the bearing in free wheel mode. I imagine the fellow who tried to start his high comp diesel applied direct force from his drill on to the crankshaft without a one way bearing, a recipe for disaster !

I'm sorry but this is plainly wrong. A one way bearing will not help here - simply because the forces are in the same direction !!!!

A one way bearing will help when a engine starts and runs in the same direction as the starter, but faster.

 

[JohnS]

That'll teach me to engage my brain before opening my mouth (or even tapping the keyboard).

I stand corrected !

John-Som

 

[stevehuckss396]

That'll teach me to engage my brain before opening my mouth (or even tapping the keyboard).

I stand corrected !

John-Som

No big deal John, heart was in the right place. I am also a big fan of the clutch bearing.

 

[mu38&Bg#]

It's going to depend on the engine. You'll often see it drills mentioned as unsuitable when talking model airplane engines. They simply don't have a high enough RPM to start the engine. With small cylinders and leaky compression speed is helpful in getting it started. An engine with a large cylinder and large flywheel will likely start fine with a drill. A small flywheel or something like a propeller needs more RPM to keep it going.

Greg

 

[Swede]

I think drills and starters are very helpful in the early stages of getting an engine to run, and tweaking things like ignition and fuel. But the hopeful goal is to have a system that will (once "dialed in") start with a flip or two of the prop, or a pull on a flywheel.

When it comes down to it, almost all modern engines like a car or airplane are motor-started, pretty much the same thing.

Model gas turbines are a different beast. Because of the extreme RPM, a motor is barely adequate, IMO. You really need something like 25,000 RPM to get a decent cool light-off, and starts using just a motor were always hotter than air-assist. After a lot of experimentation, I went back to high-flow air routed from a leaf blower, which gives 500 degree C starts vs 800+ for the motor. And that is the way modern jet transport engines are started - with air.

 

[MachineTom]

On my model aircraft with battery ignition, ignition off, turn over by hand 3-4 turns, ignition on, bump the prop backwards, advanced timing would start it most times first try.