I am running an ENYA .46 on my Tutor II. It was orignally an RC engine. What is the proper prop size for this engine? And what is the formula for props? 11 x 4 vs. 10 x 5?

I would like to get a little more speed out of the plane?

Viva

If you want more speed then you need to go up in pitch. This is akin to shifting up a gear while driving your car. You'll get more speed on the straightaways but will lose some power for climbing hills.

The control line stunt pattern is full of hills to climb.

What is your lap times? I usually clock the model in level flight for 10 laps then divide by 10. Anywhere around 4.8 seconds to 5.0 seconds per lap is a good starting point.

You can also go to shorter lines to "increase" lap speeds without having to increase the speed the model flies. The Top Flite Tutor II with a good 40-46 engine should be flown on 60'-64' lines. You'll need .015" diameter for .40 engines and below while having to drag the heavier .018 lines around for anything larger than a .40 engine. The weight and drag of the larger diameter lines *does* make a significant difference.

If you currently run a 11-4 prop and it seems too slow but pulls the model just fine, go to shorter lines. If you're insistent on going faster then change the prop to a 10.5-5 or 10-6.

Thanks PipeMajor

Is there any benifit to running engines without a muffler?

What is the best way to convert an RC engine to C/L? I have a bunch of engines for RC that I got from my late grandfather. I never really got into the RC thing, but would like to use some of these as C/L engines? How about a C/L kit for a .60 size engine?

Viva

P.S. I guess technically my ENYA is still an RC engine, I have just tightened the carborator down to the fully open position. Would like to find something better.

I use to run 10-7 and 10-8 on all my hot 46 motors... I use to run an asp 46 with a 10-8 and when i wanted to get the pulling power id go with an 11-4. just an opinion but a 46 with a 10-5 will run a bit hot because its a little bit underloaded... just some ideas.

I'd try an 11 x 5, or maybe an 11 x 6.

Do you mind if I ask what they are ? Curiosity, nothing more.


Luke.

One of the problems with using an RC carb wired wide open is that they're usually far too big for the revs needed for stunt so fuel draw can be marginal. This can be cured by trial and error gradually closing the carb until it runs right (and at a guess I'd say maybe 1/2-2/3 throttle would be close). The best way of course is to use a venturi either made up or adapted from some other engine. It's been found that for stunt work there's a certain ratio of venturi area to engine size that gets you right into the ball park.

For your engine a venturi of about .290 bore with a spray bar that's .156" diameter would be perfect. Letter drill size of either L or M or a 19/64" drill will all do the job. If you use a smaller diameter spray bar you'll have to reduce the drill size a little because the final effective area you want will be in the range of .02-.023 sq inches. If you're thinking about running without a muffler then you'll definitely need to use a small venturi size.

I have 3 thoughts on this.

1 = I was amazed at the weight of the R/C carb on my Irvine.
I didn't actually wiegh it ( should do !! ) but the difference in balance on my
Lil T Bird after fitting it with a C/L venturi was very noticeable, as I was able
to remove a chunk of lead off the tail !!

2 = Though the same applies to removing silencers, I reckon anything over a .15
spounds just horrid without one. Suggest finding a lightwieght item instead.
These are plenty of ones that will fit, or get one of those "tongue" mufflers.

3 = If you need more power (speed) you have a few choices...
A = Use more pitch ( with some more Nitro if it bogs down on the uphill bits )
B = Shave off some wieght = less angle of attack = less drag = more speed.
C = Get a bigger motor !!