Electric Twin

[Ashnook]

Is there an article or discussion somewhere that goes into detail about how to connect up a twin brushless system? I am well used to single electric and want to build a twin.

 

Thanks.

[John Lee]

4-max do a guide:

https://www.4-max.co.uk/pdf/How-to-wire-up-a-twin-Brushless-aircraft-rev2.pdf

[Chris Walby]

Unfortunately there is a divided opinion regarding location of ESC's in relation to battery and motors.

 

Some manufacturers state ESC to battery leads should not be lengthened or that additional capacitors need to be added

 

Other Suppliers/manufacturers (including 4max) say the problem was designed out years ago and its not an issue, if in doubt contact George and discuss your application.

My TN DC3, Grumpy Tiger Cub, WooHoo and Focke Stick all have extended ESC leads (ok by George) and have not and any failures.

 

George sometimes recommends the use of a UBEC and the ESC red wires removed as it removes issues with ESC power up problems

 

[Allan Bennett]

George may well be right about problems having been designed out 'years ago', and that may be true for the brands that he sells.  But for all other brands I would check with the manufacturer if in doubt (Castle Creations, for instance, supply extra capacitor packs for use with long battery-to-ESC connections), or simply follow the general recommendations to keep battery leads as short as possible and not connect switching BEC +ve leads together.

[Ashnook]

Many thanks for your inputs, the 4-Max sheets look interesting. I think I will go for a separate battery for the receiver/servo's rather than tie off the LiPo's. Interesting throttle connections Chris, I assume your transmitter can configure this arrangement!.

 

Thanks for the help, Brian

[Chris Walby]

Ashbrook,

I kept throttles separate for my GTC as I wanted to practice spin recovery techniques. Having said that you don't need to do that then just Y lead them together, but remember if no separate UBEC is used leave one red wire off an ESC on one.

 

Really can't the point of a separate battery for RX and servos, just another point of failure 9connector), another battery that needs to be checked and probably another switch to fail at some point.

 

Some people use differential throttle for taxing assistance, all I can say that in flight differential throttle can produce a very odd yaw effect (as one motor tries to over come the vertical stabilizer) and at worse will induce a spin! The WooHoo uses 100% mix rudder to throttle and it produces a superb dinner plating spin, but its spin recover only takes a few feet!

 

[Chris Walby]

58 minutes ago, Allan Bennett said:

George may well be right about problems having been designed out 'years ago', and that may be true for the brands that he sells.  But for all other brands I would check with the manufacturer if in doubt (Castle Creations, for instance, supply extra capacitor packs for use with long battery-to-ESC connections), or simply follow the general recommendations to keep battery leads as short as possible and not connect switching BEC +ve leads together.

 

I have to disagree as its just a cop out to generalise. I was clear to say what other manufacturers recommend or not. All of the models I listed benefit from ESC's being located in the nacelles for cooling and ease of installation.

 

Can't be bothered to argue, go use ESC's with long motor leads and separate RX battery, bye

 

[Ron Gray]

I do use differential throttle on my BF110 but it is for taxiing out , take off, landing then taxi back. But then I don’t have a steerable tail wheel!

[Ron Gray]

1 minute ago, Chris Walby said:

 

I have to disagree as its just a cop out to generalise. I was clear to say what other manufacturers recommend or not. All of the models I listed benefit from ESC's being located in the nacelles for cooling and ease of installation.

 

Can't be bothered to argue, go use ESC's with long motor leads and separate RX battery, bye

 

I’m with you Chris, esc and batteries in nacelles wherever possible. 

[Ashnook]

Good points! Need to do more thinking. Model has yet to be started building so plenty of time to get my mind round things - one motor is SO much easier???

 

Brian

[Ron Gray]

13 minutes ago, Ashnook said:

one motor is SO much easier

But 2 are twice the fun 🤩 

[Ashnook]

I am looking at a 2 fuse twin with a battery in each (2200ma 4s) and linking them as parallel. Should be ok ?

[john davidson 1]

With a battery for each ESC one way is to slave one throttle to the other, simple and avoids unusual effects which can crop up. From personal experience !