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Author Topic: info about twin and electrics  (Read 1104 times)

Offline paul winter

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info about twin and electrics
« on: November 25, 2012, 11:22:06 AM »
it is long but worth watching



Offline jjorgensen

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Re: info about twin and electrics
« Reply #1 on: November 25, 2012, 03:02:27 PM »
Great video Paul. When you use a single battery with two motors does each motor get the same voltage or is it one-half the voltage? In other words, if you use motors that are limited to 3 cells, can you use a 4 or 5 cell battery, or are you still limited to 3 cells but you just double the mah?
Jim Jorgensen

Offline John Cralley

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Re: info about twin and electrics
« Reply #2 on: November 25, 2012, 03:06:51 PM »
Nice job showing how it is done!!!
John Cralley
Scratch Built - Often Re-kitted!!!
AMA 52183
Central Illinois

Offline John Cralley

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Re: info about twin and electrics
« Reply #3 on: November 25, 2012, 03:08:32 PM »
Jim,  Each motor gets the full battery voltage.
John Cralley
Scratch Built - Often Re-kitted!!!
AMA 52183
Central Illinois

Offline Igor Burger

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Re: info about twin and electrics
« Reply #4 on: November 26, 2012, 01:13:45 AM »
Be carefull with that paralel run 2 esc on one battery. In case that battery dischrges during flight (should not happen, but I saw guy who started and forgot to charge battery) one ESC will cut the power and the second will see "enough" because the other does not take any current. The result is long flight with only one motor running waht can cause "troubles"  ;D

... btw how you controll landing gears in such emergency?  ;D

Offline paul winter

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Re: info about twin and electrics
« Reply #5 on: November 26, 2012, 03:02:11 PM »
hi there
the escs have a 10% cut off built in i think !!!!

also when you loose any power the eflight retracts come down
pw

Offline Tim Wescott

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Re: info about twin and electrics
« Reply #6 on: November 26, 2012, 03:41:55 PM »
hi there
the escs have a 10% cut off built in i think !!!!

also when you loose any power the eflight retracts come down
pw

Ahhh, but:

The ESCs have to measure the voltage, and no two devices are going to measure the voltage the same way.  So one ESC will always cut out first.  When that happens then the current drain on the battery will drop to 1/2, the battery voltage will recover somewhat, and the other motor will just keep on truckin'.

And the eFlight retracts may come down when you lose all power, but probably not when you lose some.

This is an interesting problem.  You could make a timer that would account for all of this, but I don't think there are any that currently do.  You'd pretty much need a special timer; one that monitors voltage like Kieth Renicle's does, but that controls rectracts based on both time and voltage.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline paul winter

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Re: info about twin and electrics
« Reply #7 on: November 27, 2012, 06:05:20 AM »
hi Tim
it like crashing lets hope it never happens  lol

paul

Offline Howard Rush

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Re: info about twin and electrics
« Reply #8 on: November 28, 2012, 01:05:21 AM »
That's one way.  Reckon there's a market for a monitor that puts the gear down and stops the second motor and maybe stomps on the rudder? 
The Jive Combat Team
Making combat and stunt great again

Offline paul winter

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Re: info about twin and electrics
« Reply #9 on: November 28, 2012, 03:54:26 AM »
hi Howard
how r u ?

miss flying in the US but theres always next year

i have had 20 flights with a test bed plane with retracts and  a twin electrics ,no problems SO FAR

The thing i find when the horizontal cg is almost perfect ,as there is no u/c hanging down or a heavy motor ,is that the model turns so much better and trimming is almost non existent .

the only thing will add  is don't get complacent with the electrics otherwise something will come back and bite you .
PW


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