I see that some ARF choices out there are nitro push props. I was wondering, on planes like these, is the propeller reversed, or is the engine somehow reversed in direction? If so, where can you by a "reverse" prop or how can you get your engine to spin "reversely"?

Appreciate the help!

Kevin

The prop is reversed. Look for props called "Pushers"

Also note: A pusher prop needs to on the engine "Backward" - that is, look at the prop, determine which is the leading edge and trailing edge. The leading edge faces toward the engine and the trailing edge faces the prop nut.

This means that the engine's shaft faces the tail!

One more thing, putting a standard prop on an engine backwards will not turn it into a pusher prop unless you also reverse the engine's direction of rotation, which is usually not practical unless you fly electrics or reed valve Cox engines. Pusher props have a reverse pitch so the engine can run in the normal rotation and have the prop push.

If you take a nut off a bolt and put it on backwards, you still have to turn it the same direction to tighten it. Likewise, if you install a tractor prop backwards, it still pulls, rather inefficiently though.

With an engine that turns in the normal direction (even when it's pointing backwards) you must use a special pusher prop as others have said. The range of sizes is much more limited than for normal props though. Some brands of engines have a special reverse rotation crankshaft which means you can use the normal type props put on what seems to be "backwards" on the engine. If you have an engine with a removeable front end like the earlier OS and Enyas then you simply undo the screws, turn the front housing so the carb points out the side by the exhaust and it then runs in reverse direction as well as it did the usual way. Well it does if you put the screws back in

There's a couple of cautions though. It's not a good idea to use a plain bearing engine as a pusher because all the prop thrust goes against the crankcase itself and the shim washer isn't designed for continuous use like that. With a reverse rotation engine there's far more chance of throwing a prop because the firing impulses are then trying to loosen the prop nut.

Here you go. I found a dealer for push props...

http://www.topps.com/Confectionery/N...op_splash.html

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Ah, Ha, Ha, Ha, Ha, Ha, Hoo, Ha!!
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No, really here: http://www2.towerhobbies.com/cgi-bin...P?&C=QBD&V=APC

http://www2.towerhobbies.com/cgi-bin...&I=LX1503&P=ML

another link for pusher props

what are you lot like eh?

towerhobbies sell good push props (props, not pops) and im not sure about running an engine in reverse... but seeing as they are 2-stroke and there is no timing/cams/valves to mess up i dont see why you cant fire it up in reverse... but dont try it, i probably dont know what im talking about

Here's an old Enya 45 with the front housing rotated 90 degrees. This alters the crankshaft port timing and now it will only run in reverse. Or it would if I put the screws back in

It's too bad it's not that easy to get an engine to run backwards anymore. Running one engine backwards comes in real handy on some twins!!!!

Ken

yep, counter-rotating props could be handy to have...

but say you had a Cessna Skymaster (with a Push + Pull prop), you would have to have one of the engines in reverse or a prop reversed...

and what prevents them firing up in reverse? theres no cams or intake valves like a 4-stroke, so how come?