Four Engine electric setup

[Den Moran]

H!

I have given up searching through the tortuous search engine - yes, it still only has 'Electric for beginners' as a title, as apparently there are NO experienced flyers who use electric-motor driven aircraft in the UK. News to me. Also, whatever you do, don't expect the search engine to deal with a multi-word enquiry, such as 'multi engines', unless, of course, you want to get into i/c!

That's the beef off my chest, and my apologies to those of us who already know all that.

I will be building a replica of the Short Solent that was used on the 'Coral Route' from NZ to Fiji, (I think), and am starting to look into how to set up the wiring for a four engined aircraft. I have actually visited the aircraft I'm talking about, it's in the Museum of Science and Technology in Auckland (which has Keith Park's Hurricane on a pedestal outside!), along with a Short Sunderland (the last pilot of which I spoke to. Oddly enough, he was stationed just down the coast from me at Pembroke Dock!) .

I understand how to set up twin electric-motored aircraft, but would like any information on setting up three or four-engined (I also have a Graupner Ju 52 waiting in the wings!) aircraft. Thanks very much in anticipation of your replies - an enquiry with the brilliant membership here never fails to get help when needed. It's much appreciated.

Hope everyone is keeping safe, happy plaguing, Den, Abertawe.

[David Hall 9]

I had once considered how i would set up a four engine model for electric. The problems for me were, where to put the battery and how to control the motors.

The battery position was easier, I guess. One battery for each side.

The motor control, without being too techy, was to put the inner and outer motor pairs onto their own channel and to apply a curve to the outer motors to delay their power-up slightly behind the inners.

Never got past any planning and now other projects got in the way.

[Bob Cotsford]

Den, your best bet for searching would be to use Google or similar, if you want to restrict the search to this site add 'site:modelflying.co.uk' to your search terms.

Personally, I've only gone up to two motors. Smaller models I've used one central battery, larger one battery per motor. For a 4 I'd pair inners on one battery, outers on another but that's just my theory.

[Simon Chaddock]

Den

Is your problem the actual wiring of a 4 motor setup (really no different just more parallel paths) or how best to set up battery(s)?

I have done fours with one battery and 2 independent batteries (1 for inboard ,1 for outboard) and I am even thinking about a six with 3 batteries.

For me the issue, particularly with a four, is what happens if a single outboard fails for some reason. With props the outboard is likely to be a long way out. Such a failure is bad enough in full size at critical flight stages but as RC models tend to fly at critic flight stages (2 seconds from the ground?) much of the time and they use significantly more power to fly the effect of a motor loss is more pronounced.

It really comes down to what type of failure you consider the most likely.

For a motor failure, particularly outboard, with a single throttle unless you have the height to test if the rudder has sufficient authority the best course of action is to cut the power completely to regain control and dead stick. This of course assumes you recognise the fault before control is completely lost.

For a battery failure it does make sense to use a separate battery for the inboard and outboard pairs as the failure will only effect the power level not the control. Protecting against a battery failure does bring in the issue of battery redundancy for the plane's control system and the means to achieve it.

My own preference is to ensure the motor/ESC/battery combinations are kept well within their specifications and to rely on the inherent reliability of electric power and just accept a failure should it happen. Crashed a four a few times but not from an electrical power failure.

I hope this helps.

[Ron Gray]

What about multi rotor ESC / Flight controllers?

[Cliff Bastow]

Den,

If its wiring setup you need  you can go to 4 max website they have diagrams of various wiring options which you can download for free.

On my Connie I used one battery driving all 4 motors and experienced no  issues. I did use a separate flight battery for the radio.

Indeed on one flight I lost a prop in flight and did not notice any difference in performance!

My Hobbyking lanc also uses one battery for all 4 motors

Edited By Cliff Bastow on 11/05/2020 12:51:13

[stu knowles]

Have you seen the Short Solent in the plan range from Ivan Pettigrew??

[Glenn Philbrick]

This is a pic of my first lanc that I lost when one motor came loose. I have since built another one still in existence and flown regularly. There is a lot of chat about where to put batteries on multi models, I have always had a single power source in the fuselage and powered the motors with long leads from there with out any problems. All motors are powered together through Y leads with just one red wire to power the RX. The only thing I have done is to use a small lipo for the retracts. There is an interesting article that I have posted the link for ( if it works) about putting extra capacitor in the ESCs and this I have actually done on my last Lanc. Castle creations actually make a pack for this but I used capacitors from RS.

The link to the article is http://www.schulze-elektronic-gmbh.de

I'm not confident the link will work as I downloaded it a long time ago. If you are interested and cannot get the link to work I could try scanning it

Good Luck

Glenn

[eflightray]

It could be one of those, it depends, questions.

What sort of set up is required, how many batteries, where are the batteries in relation to the ESCs, using BEC or Nimh for the Rx, etc.

I currently have a B-17, Lancaster, and Sunderland, all also have differential throttle, (which will depend on the Tx having mixers). It's handy on the Sunderland as flying boats tend to weathercock easily when turning down and across wind.

Ray. (Neath).

[SR 71]

Im doing a 6 engine model and i intended to use 6 lipos and ESCsall in the fuselage, controled by the throttle and a slide switch

[Den Moran]

Thanks, everyone! A lot to consider, but I will probably set up a two 'twins system', inner and outer, I have an example, with a Coronado seaplane being built on youtube in Australia, and will revisit that video whe I get the chance

Keep safe, and diolch yn fawr 'to, Den, Abertawe.

[Tony Richardson]

Den do a google search for "Rays models" Ray McDougal is the guys name, he is a Canadian and has built several multi engine electric models, and i am sure he would answer any questions you have, take a look at his website and checkout his builds, some really good models there a few of them from Ivan Pettigrew plans..

[eflightray]

Another Ray's models, mine -- my model web site

Ray, (Neath).

[Den Moran]

That's great, everyone - I followed Tony Richardson's advice and contacted Ray McDougal in B.C., Canada, and had a very informative, courteous reply from him.I feel I can now move forward to build the aircraft, especially given the member's great pics of their aircraft. Diolch yn fawr, pawb, Den.

[Tony Richardson]

Glad it worked for you Den, Ray is an old clubmate and I have had a lot of help from him over the years, his builds are amazing.