RCU Forums - engine...

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when they say .40 is that the size or the power... if it is power im guessing that the higher u go the more powerful it gets..

it is the cubic inch displacement of the engine. .40 means the engine is .40c/i if you go with a .50 you have a half a cubic inch. 1.0 is one c/i and so on. the higher you go the more power.

sean

Right. Until you get into gasoline RC engines, then they start talking about cc's. :eek: For what it's worth, 35 cc's is about 2.2 ci. ;)

You can get the glow engines marked in CC's too... The Webra 10 is a .61. (and that is also the conversion formula for cc to ci. :D

K&B engines used to be labeled in cc. (sometimes... seemed like they couldn't make up thier mind which to use. :eek: )

The reason most Gasoline engines are marked in cc's is.... they started out as conversions from weed-eater (and other small gas power yard tool) engines. And practically all of the gasoline power weed eaters and such are marked in cc's.

I you want to compute cc's to cubic inches and cubic inches to cc's, divide cc's by 16 to get cubic inches mulitiply cubic inches by 16 to get the cc's. So the .40ci is about 6.4 cc's seems to work that way.
Remember there no replacement for displacement !!!! [&:]

Remember there no replacement for displacement !!!!

Turbo!!! :D

Morning nitrobraster, yes to your question.;)

It is a general requirement for engine size for the model. A 40 size engine will fall between certain sizes and weights. The kit manufactuer reccomends a certain size. You put what you want on. When they say 40 they mean between a 40 and 53 two stroke engine. I hope this clears up any questions.

Mark Shuman

Actually... when they say .40... they mean .40. If they say .25 to .40, they don't mean .46 is approved. (they don't even mean .42...)

One of the worst habits being taught to beginners is the standard practice of putting oversize engines on models.

the beginner doesn't have the experience to know what plane its safe to "hop up" with a bigger engine.
the overpowered models tend to get flon at speeds they aren't designed for... and they snap the wing in flight. (Must have been a defective kit or ARF[:@]... bad design[:'(]... not my fault.:eek:)
The beginner has more problems keeping u wth the model in flight... training takes 2 to 20 times as long.
The airplane can be overweight from the hunk of metal on the nose... (and the corresponding lead in the tail to ballance it) making it have worse stall characteristics. (I thought the review said it was a forgiving plane... snaps like heck on final.[&:])

When you KNOW what your are doing... THEN you can go outside the recomended engine range. Till then, DON'T!