How about some info on how to set up twin engines. Mechanically as well as mixings with a computor radio. Need to see if I'm doing it right. JG

OK, my two cents.
ALWAYS use two servos, never one and linkage. If you have a computer radio, mix the second to the throttle as master. Makes much easier adjustment of idle through full. Can use exponentia to sync the engines by controling and matching one to the other. OK, more? Now mix the engines to the rudder, but never allow this mix to work below 50% throttle position. Is dangerous for taxiing if you do.
This makes knife edge and spins much easier. To get out of a spin, simply reverse the rudder and the single engine guys wonder, how do you do that.
I have even put the Hobbico Aero gyro in between the receiver and the two throttle servos to stabilize a hover, but I am nuts too!!
There have been numerous posts in the past on this subject, and you can use the search to find more,but have fun.
Good Luck,
Twinman

Jim:

I will agree with TM on using two servos. If you have room. The Tiggerkitty has a lot stuffed into a small fuselage, I used one servo for both engines. Using the Sullivan flex cable I can adjust the sync at the E-Z connector at the servo end. No, there was no room left in the nacelles for servos.

Picture attached.

Top left is rudder/nose wheel steering, elevator servo beside it. The lower right servo is the ailerons, and beside it you see the throttle servo with the two cables for its operation. The thing that says "PGM 4" is an 850mah battery, the switch is behind it with the knob outside on the bottom with the charging jack. The Hitec 555 rx is pulled off its Velcro, sitting on the wing for the picture.

And it has worked well for a bit more than ten years now.

Bill.

Bil, it might be me, but it looks like your ailerons are not getting the same throw ... the angle in which the left nirod is connected to the servo will give it more pull and less push then the right one ...

But if you say this works for 10 years ...
Maybe the servo is not at center position when the pic was taken ...
It will still give you an amount of aileron differential ...

Am I wrong?

Yakir

Yakir:

That uneven angularity is corrected by having the horns at the rear ends, on the aileron torque rods, at different angles. The resultant travel is the same.

Bill.

Thanks guys, The throttles are one servo each and mixed throttle to aux 3. I got two flites on today with both engines running about 100 rpm's apart. Mid range was alittle further apart but not bad. They sounded pretty close in the air though. I thought I might have to put some point mixes in but I have not done too much with that,so I am opting out right now. Thanks Jim G

I have had good successs using one servo for both engines and mechanically getting the throttle set-up on each carb for each engine.....it sounds wonderful if both engines turn the same RPM.....but if they're a hundred or two off, not a big deal....... .If one servo fails in a mid to high power setting...makes for an interesting flight to say the least......also have a remote ignition kill for both engines as an extra failsafe .......so one way or another ...I can land with both engines shut down if needed.....most important to have identical or nearly identical RPM on approach and landing.........it takes alittle extra effort to get the geometry correct for both engines.....but has worked well for me.....regards...........Bill....

I guess I am the odd ball. I fly both my P38 and my 102 " C130 on one servo for the engines, everything is bellcranked, I use an EZ connoctor on the throttle arm and adjsust the throws, it has not let me down yet, ask Twinman about my birds MIke

Yes, MultiMike is one of those premiere builders that make the rest of us feel bad. He builds a 80" P-38 with engines at 9 pounds or a C-130 at 102", with engines at 15#.
Wish I could have the time or patience to do that.
Thanks for the input Mike,
Twinman

Hello:

I used one servo for each pair of engines in my Lancaster. I used Nyrods to each engine and have not had a problem with engines running smooth. Both servo's were connected using a Y connector and all four engines were running very reliable, when increasing and decreasing the throttles. In my opinion any method will work as long as your engines are running reliable. I checked the RPM setting out of curiousity and found only a difference of about 300 RPM's which was not an issue while in flight.
Multi engines is the way to go!!!!!

Craig

Well, I have about 8 flites now. I set the servos on my point mix and matched the top, middle and bottom. Rpm's stay about 100 apart all the way to the top. The sound is great. I don't think I will need to mix any more points? Things seem pretty smooth.