Cox throttle sleeve port sizes question.
 

Well, I feel kind of stupid for not noticing before, but I just realized that the throttle sleeve I have on my baby bee has ports that are only about 70% of the head ports. I'm assuming the port sizes must vary or is this normal?

Also, any suggestions on opening the ports on the sleeve to match the head? Want to use the throttle on my just finished LS150 (looks to come in at 10.5 ounces AUW) but don't want to choke the power with too small ports.

Duke

RE: Cox throttle sleeve port sizes question.
 

It's normal.
I think that you'll find that the throttle robs very little power. From playing with a few exhaust throttles, and a couple I tried making myself, I've found that half open gives you 90% of the power. If you try to enlarge the ports you'll end up with a an idle of 10,000+ rpms.

RE: Cox throttle sleeve port sizes question.
 

It's a trade off... I have found as you make the ports smaller the more linear your throttle response.

RE: Cox throttle sleeve port sizes question.
 

You'll find that the ports are sized that way so that they match the width of the bypass flute pillars. Any opening at all when closed will be way too much. You'll find that the gap between the sleeve and the ports is all the leakage they need for idle operation.

RE: Cox throttle sleeve port sizes question.
 

Thanks guys, I guess I won't worry about it. With the ports closed 100% it has a rock solid idle that I don't want to mess with.

On the last plane I had it on, I landed at the end of the runway at idle and it was so quiet you couldn't hear it at all at the flight line. One of the guys told me to hurry up and go get it since he needed to land. I was able to just tell him that there was no need to go out and get it and just blipped the throttle to taxi back to the line :D. Got a good laugh out of the look on his face that time. He's the one that always tells me how bad small models fly and how useless the small engines are.

Thanks,
Duke