Slide vs. rotary carb
 

There are several motors where the manufacturer sells the same motor but with a slide carb or a rotary carb (and usually different shafts too). For example the O.S. CV-R .18, or the O.S. TZ .18. Performance wise, what's the advantages of the slide or the rotary carb on an otherwise identical motor?

Slide carbs will typically provide a more linear power band. Versus a rotarty carb givin a more punchy feeling.. With a Slide carb the input of fuel and air is equal as the carb opens, assuming the needles are correct.. I don't know what the %'s are but for example 50% air = 50% fuel which equals 50% power..

A rotary can have a point in the middle where it may go a touch lean, and at like 60% throttle open on a Rotary carb is like 85% power..

And, IMO Slide carbs are easier to tune and keep tuned.

Hope that makes sense.. This is what was explained to me about 8 years ago when I started playing with RC's.. If it is incorrect I am sure someone will correct it..

Going along with the previous poster's post, the difference between a slide and rotary carb lies in the first half of the throttle pull (or rotation). The fuel mixture goes straight into the crank as the throttle begins to open on a slide carb, while the the fuel mixture has to zig-zag as the throttle begins to open on a rotary carb.

Like I said, this difference in flow impacts the motor from 0-50%ish of the throttle pull. And its this smooth fuel flow on a slide carb that gives it such sensitive, immediate throttle response.