naynay12

What is the difference between a straight shaft and bent shaft engine,why is straight shaft engines recomended for rc projects?

Dirty_Vinylpusher

Um.
Are you talking about Whippersnippers?
In that case it would refer to the actual shaft between the motor and the cutting head.
The bent shaft ones are usually quite gutless compared to the big straight shaft ones when it comes to cutting grass.
I guess the motors aren't that big and have less torque....
Trust me on this - I used to work for the council and spent countless hours on the ol' whipper.
I hate those bent shaft things.
They're ok to do a couple of metres of edging but all in all they're a waste of time. (For grass cutting purposes that is)
Sam will know - he seems to be the resident expert on little 2 strokers.

Naynay while I have your attenion, how about some pics of your build(s) please?
We're missing you over on that other thread....[]

da mad maori

a bent shaft is also called a flexshaft which is a cable.... only have them on small engines

straight shaft is a solid steel shaft... mainly on big brushcutters.....

the engine is separate from the shafts

Dirty_Vinylpusher

Yeah give me a big Stihl monster any day over one of those little hand held jobbies.
Harness, bull horn handles - the works![>:]

I love being a bloke.
There's so many things to get excited about.

da mad maori

LOL your not wrong

naynay12

My car is apart at the monent, since the hpi transmission has gotten eaten up,even after replacing the plastic gear with a 7075 alloy one...So im about to buy sprockets which will cost about $30us.With the rtaio 7:5:1 it would reach top speed within a couple seconds,and had way to much torque,so i was thinking of gearing it somwhere in between 5:5 and 6:5,some advice would be apprciated,it has 26cc engine,and 6 inch hpi savage tires.

I found a steel whipper snipper engine with a clutch,about 25 cc,and it is bent shaft,tell you the truth i was thinking of using it on a scooter but its bent shaft...

Dirty_Vinylpusher

I remember Sam123 saying somewhere that with these whippersnipper motors, the better ones are the ones that have the pullstart at the back, not on the clutch side of the motor.
Which makes sense I suppose, as they will have a solid crankshaft going all the way through, instead of just ending at the conrod.

Also - applying what I know about car motors - slightly lower cc motors will rev harder than the bigger ones.
Most people who hot up their VW's will go for the 1600 or 1800 motors as opposed to the 2 litre ones.
I used to have a Holden ute with a 186 in it and it had more guts than the 202 I have at the moment.
Go figure.

sam123

My Feedback: (1)

Gday naynay12.
The straight shaft whipper snippers usually come with full-crank engines, which are far more robust than the half-crank engines that appear on most of the bent shaft whipper snippers. Full crank means that there are 2 counter weights and 2 crank bearings supporting either side of the crank shaft. Half-crank engines usually have very messy transfer ports compared to full crank engines. They also vibrate alot more. these two factors have a big impact on the overall performance of the engines.
Some of the old bent shaft whipper snippers come with good engines, like the kawasaki td18.