skycom

How are you guys setting the throttles up on your twins. 2 channels on the radio, each independently adjustable? Anyone using governors to get engine running at the same speed? Just curious as I'm starting the install on my Dual Ace

TCBLightning

My Feedback: (5)

I've always used two servos on a Y-harness. With good motors (broke in) it might take 2-3 flights of adjusting the throttle linkage but once it is set they are good to go.

cyclops2

2 servos BEAT all others for accuracy, cost and repeatability after any repairs.

They are TOO simple not to try the first time. [sm=thumbup.gif]

Wayne22

My Feedback: (2)

I'm using 2 servos. With my 9303, I can trim them independently, and set endpoints etc.

Build-n-flyer-RCU

My Feedback: (4)

Just about everyone here will agree that two servos is the way to go.

I prefer going with independent channels for each engine. I also fly the new 9303 which comes with twin engine support built in- two independent throttle curves for each engine.

But if you have two well-broken in engines it is not that hard to get them in synch using a single channel and a Y cable. Using a matchbox on a single channel to make minor adjustments is also an option.

Engine synch really doesn't affect flight performance noticably, it just sounds better- especially if you are running 2-stroke engines.

Walt

Ed_Moorman

My Feedback: (1)

I fly a JR 8103 and I also use 2 servos. I have mixed 2 channels and also use a JR Matchbox or an Equalizer on 1 channel. The gadgets (Matchbox or Equalizer) are quick and easy, but an additional cost. If you mix 2 channels you can also mix a throttle curve, if necessary.

There are going to be guys who will tell you that you can use 1 servo or a Y, but for ease of installation so you can fly instead of fiddle with your set-up, you can't beat 2 servos. I mean what do you have a computer radios for if you are going to "stone age" it with 1 servo.

KidEpoxy

Live from the Stone Age-
Heythere, I used my finest stone hammer to get both on one servo, and tweaked the needle to get the stronger engine down to the same rmp as the weaker at full throttle. Sure it's not perfect, and I go a bigtime right yaw at lower throtle... but I'm a cheapbasserd and saved few $ on a servo to get the bird up under budget.

To each their own, just saying you can still fly & have a good time with 1 servo.... just get good enough at approach to deadstick it in to beat the yaw.

MaJ. Woody

My Feedback: (28)

Two servos....one channel. A bit of setup work involved (there always is getting two engines to run perfectly together) but after that your done.

Dom

ehfleming

My Feedback: (5)

2s+2c, 2s+1c+y; both = [8D]
1s+1c=#@&[:@]#@!!

clscale-RCU

My Feedback: (7)

I have always used 2 servos with one channel hooked together with a Y-harness. The pushrod and setup is so much easier.

to get the engines scyned I do the following:

1) run #1 engine, adjust the high speed needle valve until it runs good and idles

2) Run #2 engine, adjust the high speed needle valve until it runs good and idles

3) DO NOT adjust the needle valves after this point....

4) Run both motors at the same time, throttle back and figure out which one shuts down first

5) Shorten or lengthen one throttle pushrod to speed up or slow down one of the engines. I accomplish this by turning one of the clevis on a threaded pushrod (notice the needle valve is not touched)

6) Run both engines again, throttle back and see if the engines shuts down at the same time

7) Repeat step #5 and #6 as needed until the engines idle and shut down at the same time

My twins work great with this system, the RPM of each engine may be off by a few hundred RPM but that is about it.


Good luck.

BillS

I would like to see a photograph of the single servo set up.

Bill

William Robison

My Feedback: (3)

BillS:

I like individual servos also, but only because rigging the linkage to a single is a royal pain. All my twins except the Tiggerkitty have dual servos, I didn't have room in the TK for minis, and at the time I built it the micros were in the $70 range. Even the HS-205BB servos that I used were around $50 then.

In the first picture the servo on the left front is the throttle. It drives Sullivan cables to each nacelle, nd a ball end connects the cables to the throttles.

Bill.

desmobob

I just broke in the engines on my first twin, a Hobbico TwinStar with Super Tigre G34 Heli engines. I used individual servos on seperate channels mixed together on my Futaba 8 Super Tx. It worked perfectly. In hindsight, I don't think it would have been any more difficult or time-consuming to use a Y-harness and make the adjustments mechanically.

Good flying,
desmobob

KidEpoxy

BillS-
If you ever used a single servo to work both ailerons, it's the same deal, but the outer leg goes down into the nacelle to a forward link instead of to the rear into the aileron. You put both inner legs on the same side of the servo horn lest they throttle opposite eachother. I was just bashing a glider and looks were far behind budget, but here's a pic with the servo sticking out the top of the wing rather than down into the fuse... and the torquerod ends sticking up at the back of the wing. If looks are important to you, you can do it far more internally. But I didn't have my Stone Age Club set to Internal when I bashed this out

Or you cable it like TigerKitty

helipal

Guy's with futaba 8U's & 9 C's - Try using the needle valve channel to control the second engine. You can use the throttle curve on the primary to sync (after optimal engine needle setting), and with the needle channel set up correctly to dive the 2nd throttle servo, you still have throttle cut of both engines - Been working well for me on a couple palnes now

Terror Dactyl

I can also suggest that there is another feature that using two servos will help with. When you mix the throttles to the rudder (switchable hopefully) you can get help in turns and if you are really wanting to play it will also help with spins.

Beware when you set up the mix. Twinman found out what not to do luckily without damage to plane or people. You have to set it so that which ever side you turn the rudder to that motor will be slowed down. As it is ithe insde motor then the other motor will help the plane to turn.

Make sure if you are going to use the bird for high speed spins that you keep a little throttle in the inboard motor or it will die from fuel starvation, again Twinman found that out as well.

If it si not switchable then I believe that you can work the mix so that at the landing throttle setting there will not be any noticable engine drop.