cbedwell

My Feedback: (9)

I'm not really new in R/C planes, but have been out of the hobby for a few years because of some physical problems. Now, I'd like to get back into action, and the project I'd like to undertake is a multi-engine 1930's bomber. My question is "how do I synchronize the two engines?" Do I use a separate throttle servo for each, or somehow hook them together on a single servo? Any help will be appreciated.

BillS

Someone else will provide better answers but I always use two servos.

Bill

Ed_Moorman

My Feedback: (1)

You can do it any way you like and there are proponents of each who have good flying twins.

1 servo: a pain to do unless you like to tinker. Hard to get idles together and make adjustments.

2 servos on a Y: Easier, but mechanical adjustments needed to get throttles together.

2 servos, single channel with a JR Matchbox or Equalizer: Very quick and easy to set-up. Allows individual adjustment of direction, center and both end points. High priced $40-$70.

2 servos, 2 channels, mixed: Easy to do with a computer radio. Allows all individual adjustment. With a 6-channel receiver, you can run out of channels. You also need to use a trimmable mix, 5 & 6 on JR radios so you can have throttle trim on your second engine. The advantage of mixing is you can adjust one throttle or the other without taking the wing off.

I use both of the latter two on my twins. Call me lazy or that I just like gadgets. I am used to using mixing so it's easy for me.

Bear in mind there is 1. synchronize throttles: getting the 2 engines to throttle together, and there is 2. synchronize rpms: getting the 2 engines running the same rpm. I do the first and ignore the second. To me, it is a big pain to sit there with a tach playing with the engines when I could be flying. I did some testing and found 1,000 rpm didn't make any difference in how the plane flew. I also ran a twin with a TT .46 in one nacelle and a TT .42GP in the other. Couldn't tell the difference.

jaka

Hi!
Separate throttle servos mixed together is good to have but surely not necessary.
I'm a firm believer in the KISS principle (Keep everything simple stupid).
Otherwise it's simply choose good reliable engines and learn how to set them properly.
Always build light! and always question whether or not a part is needed or not and if needed ...if it couldn't be built lighter or substituted with a lighter part
It is also good to be a good flier so practice aerobatics a lot and if possible start flying pylon racing as those guys are the best fliers around and you learn how to set engines, trim airplanes and learn how to cope with fast airplanes, flying low and tight in a stressing environment.

Regards!
Jan K
Sweden

emspilot

Hmmm..."Matchbox or Equalizer". Is there such a device compatable with Futaba equipment, or is this purely JR?

The other problem I have is that I don't have a trimable channel to slave the other engine to. Am I stuck with using a y harness and going off of one channel?

archyroof

It depends what radio you have i think. If you have a good computer radio, it would be easy to mix two seperate servos for the throttle. If you dont have a computer radio you could use bell cranks.

Dean

WA Flyer

I don't know about the matchbox or equalizer, but I use a Futaba MSA-10 Servo Synchronizer on my Twin Otter. I have heard that it is similar to the JR Matchbox.

Paul