Easy tips for making a solid connection on multiple motor setups
THIS MONTH I’ll be explaining how to go about setting up planes that have more than one electric motor. It is no secret that I am a big fan of using E-power for planes with multiple motors. To me, the advantages far outweigh the disadvantages when compared to glow power. First there is the clean factor; you never have to wipe oil off of your plane when using electric power, unless of course you flew too close to the overly rich glow plane or landed in an oil spill. The other thing is reliability; you never have to worry about getting both motors started and there is only a very rare chance of a motor quitting during the flight. Glow-power twins do have one great feature, though: that fantastic sound they make as they fly by. There is nothing else like it, but I would still give up great sound over reliability any day. So, let’s see what we need to do to properly set up a good running electric multi-motor plane.
WHAT TO LOOK FOR IN A TWIN
The first thing you need to consider is having an easy-to-reach compartment for the battery pack(s). As with all electric planes, you want to be able to easily remove and install battery packs for changing. The plane just has to have an open area that would be able to fit the packs; you may or may not need to make some type of removable hatch for easy access to this area. It would be a good idea to have the battery compartment somewhere near the CG so the additional weight of the batteries will not need to be compensated by more weight to balance out the plane. Many twin planes will have a center fuselage that will be perfect for this. If the plane you are considering for E-conversion only has space for the batteries near the rear of the fuselage, you may want to consider using a different model.
The second thing to think about is easy access to the motor location or nacelles, especially for ESC placement, which should have some type of airflow going through it. There should also be some easy pathway through the wing for all the wiring you will need to run to the battery and receiver. Once your plane has met these requirements you are ready to install the E-power system.
FIGURING OUT WHAT TO USE
One of the hardest parts of doing an electric setup is just trying to figure out what motor combination to use for your plane. Fortunately for us modelers, many manufacturers are more than willing to help you out. A simple phone call is all you need to make to find just the right motor for your conversion. Many hobby shops and manufacturers can tell you what motor will be right for your plane if you let them know what size gas or glow motor the plane is made for. You will generally have a couple of equivalent motors that would work well for your application. For me, I like to use the stronger of the selections just to make sure the motors are never over-stressed, which could happen if you pick the weaker motors and rely on their maximum performance all the time just to fly the aircraft.
Once you have the motors selected the rest falls into place. The ESC needs to be the right type for the motor (brushed or brushless) and be able to handle the maximum about of current the motor will require. For example, let’s say you have a motor that normally runs at about 30 to 40 amps but has a maximum limit of 50 amps; you should get an ESC that can handle 50 amps.
I have an old Pica Deullist 240 kit that i am finally getting started on. I had originally planned on 2 x .45 glow, but with the improvements in electrics since I bought it, I am now looking to electric. I have no experience with electric, so it is a very ambitious project. Your article is helpful, but I need to learn a lot more before powering the plane. From what I see, the build is normal, but most of the changes need to be made at the addition of the motors, correct?
I am a Offshore Electrician and for those who may not understand series, parallel or series/parallel .. Maybe you could but a wiring diagram in the article. DC voltage is as dangerous as AC voltage. Don’t forget battires are stored energy. Be safe and have fun.
I have a Beaufighter scratch built in gestation, ⅛ scale, wing span approximately 87 inches, wing area 7.86 ft², frame weight (no engines or undercarriage) 12 lbs. I originally intended to power it with a pair of .60 two strokes however I am now investigating the practicality of using electric power. I can see the advantages of electric and having flown twin 2 and 4 strokes in the past and experienced the difficulties and frustrations therein I am interested in the alternative.
I have been searching the forums for relevant information on twin electric set ups for a model this size and have so far been unsuccessful. Your article is the most informative I have found.
I am particularly interested in:-
1. Motor/prop choice. My experience with twins is that two .40 four strokes do not provide equivalent power to one .80 four stroke (I built two almost identical sport models, a twin and a single, the single .80 would climb vertically to around 500 feet, the twin .40 would quickly run out of speed and fall over at around 150 feet. Does that experience hold true for electric? What I have found so far leads me to believe that I would need around 1200 – 1600 watts (depending on finished weight) so would two 600 – 800 watt motors do the job?
2. I would like to run scale size (or near to ) propeller which would be around 19 inch however none of the threads that I have followed so far really explain in terms that make sense to me the motor/battery requirements for swinging a large prop. My experience with electric motors is that the larger the load the more current they will consume up to the limit of current available or until the smoke comes out. Manufacturers charts that I have found for .60 or .80 electric motors do not give information for props this size. Is there some attribute of outrunner motors that will let them labour at low revs with a big prop without overheating?
3. What would be the alternatives for battery power? Single large capacity battery supplying both motors in parallel, twin battery/ESC fully independent set up, twin batteries with an equalisation strap or something else? What are the pro’s and con’s? Your article answers some of the questions but I’d love to know more.
4. Can two ESC’s be controlled from a single (throttle) channel via a Y lead or would it be advantageous to slave another channel to the throttle and have the two motor/ESC’s completely separate?
5. Is there a way to adjust (balance) the out put of a twin set up or is the quality of modern motors/ESC’s such that this is unnecessary?
There is plenty of space in the nacelles of the Beau for motors and batteries, there would be good airflow and the positioning of the weightier bits well forward is attractive in a snub nosed design so that’s the way I’m leaning at the moment,.
Any advice welcome.
Good basic info, Thanks.
why do I have to cut one of the red wires from.
the esc when setting up a twin rc model.I keep reading about this but nobody will explain why
I AM STILL AWAITING AN ANSWER TO MY QUESTION ON CUTTING THE RED WIRE OF ONE OF THE ESC WHEN USING DUAL MOTORS
you cut the red wire so you don’t have voltage going from both BEC on the ESCs going back to the receiver. it is best to only have one BEC voltage coming back to the receiver to prevent any conflicts and issues.
JOHN- THANKS SO MUCH FOR THE INFO. I WILL CUT ONE OF THE RE LEADS
I installed 2 motors on my DC 3: one regular and one counter rotating because I thought it would be great to cancel the torque. Unfortunately, the counter rotating motor is pulling more. (props are the same, of course one is R) How can I balance these 2 motors?
Photograph seems to be of an OV-10 Bronco, and not an A-26 Invader!!
Hello, I am planning on building an RC b 25 Mitchell. I have flown RC planes but this will be the first I have built. Do you have any advice?
Hy! Im planing to upgrade my EPP Trainer to a twin engined plane.
The Config would be: 2x MultiStar 2213 980Kv motor (Max.current(10s):15 amps
2x 30A Esc
1x Turnigy nano-tech 3S 2200mAh 25C-50C
My question is, can this battery handle these two motors in one time?
Comments are closed.