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Electric. Twin engines how to adjust to operate at the same speed ?

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Old 03-21-2014, 12:57 AM
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Boormans
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Exclamation Electric. Twin engines how to adjust to operate at the same speed ?

Have a futarba t8fg and want to trim two electric motor so they run close to each others speed . Running separate speed controllers and dual batteries connect in parallel . Have tried the master and slave 3and 7 , trim to ld and rd knows I must be missing something in the set up procedure ? need step by step instruction please if anyone can help
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Old 03-21-2014, 05:52 AM
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any reason not to use a Y cord and simply plug both ESC's into the throttle channel?
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Old 03-21-2014, 08:37 AM
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Jim's answer is the usual way it's done and provided your using two each of the exact same ESCs , motors , and props the motor's speeds will be close enough to fly fine . Any slight difference will be well within the control surface's trim tab range of correction .

Now with that said , If I had some need to verify the speeds are as close as possible , without blowing a bunch of $$ on fancy electronics , I would use two channels mixed to the throttle stick (using the 2 channels to allow for each to have it's own trim) and then connect a wattmeter between each ESC and battery . When it's trimmed to the point where the power draw of each is as close as possible , at various throttle positions , well that's about as close as you'd get .
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Old 03-21-2014, 09:02 AM
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Y the esc's. Take the props off and do the esc calibration so that both escs know where full and off are. Using the same batteries/ motors/props will yield similar rpm.

You don't need the exact.. even nitro's did not need to match.

Despite what I was told: having owned:
Nitro:
b-17
mosquito
p-38
twinstar
f-22(nitro d/f)

Electric....(these were all conversions)
p-61
80" widgeon
PBN Nomad
p-38
mosquito
me262

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Old 03-21-2014, 09:05 AM
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now it you are going to use differential steering: you can put them on different channels. but even on my seaplanes.. I used a switch to disable that as I started my take off runs. I only used it for taxing.

And I would still y them first so they are set up the same. then plug on into another channel and mix. you could sub trim the slave channel so that they start at the same time.
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Old 03-21-2014, 11:06 PM
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Yep tried this the electric engines still run at 3000 rpm apart . The only way I thought was to use the transmitter and master and slave channels futaba T8 fg but my set up must be wrong still hoping someone can tell me how to set the transmitter up
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Old 03-22-2014, 02:40 PM
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Quote:
Originally Posted by Boormans View Post
Yep tried this the electric engines still run at 3000 rpm apart . The only way I thought was to use the transmitter and master and slave channels futaba T8 fg but my set up must be wrong still hoping someone can tell me how to set the transmitter up
If you are using a Y connector try cutting the Red wire to one ESC ( it doesn't matter which one) if have not already done so. That way only one determines the speed of both motors. They should be within 20 RPM of one another, electrics are way easier to sync than glow engines ever were.
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