Constellation to go electric.....
 

I have been working on this project for few years on and off, couple days ago project got re-started with full hopes of maiden flight in coming fall. This model was designed for 4x 40sz IC glow engines but now i want to convert it into electric powered model as it's best and safe way to go on multi engine models...I'm not sure how electric motor numerical terminology works in terms of how much power one motor can produce or should i say amount of thrust. I have been flying glow models for many years and it's very easy to distinguish what size model needs what size glow engine......

http://www.rcuniverse.com/forum/m_45..._1/key_/tm.htm
(Thread is 36 pages long, so it will take time to see this build)

I would appreciate all the help i can get so i can figure out what type of motor, esc and batteries do i need to get to fly my Constellation safely.

RE: Constellation to go electric.....
 

Props ... wow its a lovely project! For scale flying you want to look at the following set up as a baseline:

Batt - 5S packs (I want to see how you store them! Its going to look like an EV car ... hehehehee ...)

Motor - Rimfire 4260-800KV (12x6), China 4260 sized motors of around 680 KV (on 5S you will turn a 12x6 or 12x8 max but this is pushing the motor hard), AXI 2826/12 etc.

ESC - 80A ESC, the HobbyCity Turnigy plush are good, been using them without issues

You will want to remove the RED wires for the ESCs and power the plane with a separate supply for the RX. There is a lot of talk about keeping the wires from the battery to the ESC short, seemingly if its too long it can cause the ESC to fry, read about this before but you need someone who can explain why to give you the details. To avoid this I also read that they use some capacitor in between the battery & ESC to ensure the power supply is smooth. Maybe someone who is in the know can chip in. :)

RE: Constellation to go electric.....
 

tIANci what if i were to use 13x7 3 blade prop as that is scale prop size for my model, would i need to go bigger on motor or would adding gearbox willl do the trick on same type of motors as u mentioned?

Now i will for sure need more guidance regarding cutting wires for altering original set ups as this is not my field, now when u said capacitor, did u actually meant BEC....juss curious...

RE: Constellation to go electric.....
 

Prop, I have this setup in one of my planes. It is just a single motor, but it has all of the power of a good .46 IC engine. I use a 13X6.5 APC "E" prop.

I ran the numbers and the calc says the 13X7 prop will pull to many amps. If I used a 12X6 prop, the calc program says it is good to go. With a 12X6, it says it will pull 870 watts, with 124 ounces of thrust. That would be for each motor and prop. So you are looking at about 496 ounces of trust or 31 pounds of thrust for the (4) motors.

Not sure but if you can find a 13X5 prop, you will be at the limit of the motor. A long full throttle run and they will melt. The motor is listed as being able to handle 55 amps, with the 13X5 it say it will be at 55.06 amps.

If you use a long wires for the battery to ESC, you can increase the size of capacitors to help even the draw. I am not fully informed about why you do this, so some one else will need to help there.

You can pull the red wire from (3) ESC's and use just one to power the radio, but with a plane this size I would go with a UBEC or even a (5) cell NIMH or NICD battery and not use the lipo for anything but the motor power.

Motor
http://www.hobbypartz.com/monsterpow...ess-motor.html

ESC
http://www.hobbypartz.com/volcano-se...hless-esc.html

Battery
http://www.hobbypartz.com/83p-5000mah-5s1p-185-25c.html

With (4) of these, you should be able to pull your car around the block with out a problem.

You could set it up so you have a battery for each wing, or you could use (2) batteries to double capacity and run all (4) off the same lead.

Here is a calculator that I use.
http://www.hobbypartz.com/83p-5000mah-5s1p-185-25c.html

I will be following this thread.

Buzz.

P.S. Take some time and use the calc program. It will start to make sense after about 30 minutes or so.

RE: Constellation to go electric.....
 

Hey Buzz,

Sorry for late reply Sir, i'm thinking on getting 4x Turnigy motors with equal amount of Kv watts as Eflite 46 motors: http://www.e-fliterc.com/Products/De...odID=EFLM4046A

I also have new HK "SS" 90A-100A ESC's that i can use with those motors, i will have to get newer 5500 mah packs but not sure to get 5S or 6S lipos packs and if 1pck/ 1 motor/esc combo will be good enough or 1pck/2 motors/escs will do the job per wing......

Plus not sure to get BECs for these ESCs or not. I suppose i still have to find answers to these 2 questions before ordering these items...


Edit:

Maybe 4 of these motors: http://www.hobbyking.com/hobbyking/s...idProduct=2098

or

Even these: http://www.hobbyking.com/hobbyking/s...idProduct=4911



As for Props, ideally i want to use 3 blade props, would these MS 3 blade work with above Turnigy motors in the links provided?
http://www.hobbyking.com/hobbyking/s...idProduct=8106

RE: Constellation to go electric.....
 

I went through the calc program again. I used a 5s battery, 70 amp ESC, 13X8 3 bladed prop with the Turnigy 4260 (600) motor. I got 63 amps, 185 ounces of thrust, 8 minutes of flight time. So, I would say it is a go. I believe you will get a long flight time then what they figure.

I am not sure how the best way to wire up the (4) motor. You could go with (2) 5s 5000mah batteries. Run the inboard motors off of one battery and the out board of the other. You could wire up (4) 5s 5000 mah batteries and run all motors or, or, or ,or. I myself, and this is just my my simple idea of how I would do it. I would wire all ESC into one plug, and I would use a "Y" connector to hook up (2) 5s 5000mah batteries.

I would use a (5) cell NIMH battery to run the radio gear.

This is just me, I have no idea if any one way to wire is better then the other.


Buzz.

RE: Constellation to go electric.....
 

Buzz,

Since i already have 90A-100A Esc's on me, can i use those with these motors and batteries instead of buying newer ESCs again?

Here is another set of E 3-blade 12x8 props i found, wish they have had 13" dia props that would be perfect scale diameter...: http://www.hobbyking.com/hobbyking/s...idProduct=9018

RE: Constellation to go electric.....
 

Yes you can use the ESC's you have. As long as they are rated up to the amps you may pull. With this setup you will be around 70ish amp, the 100 amp ESC will be fine.

Looks like you will a few "Y" harness's for the ESC to Rx connections. Do not forget to pull the red wire from the ESC's if you use a separate battery to run the radio gear.

Props
http://www3.towerhobbies.com/cgi-bin...&I=LXAA39&P=ML
http://www3.towerhobbies.com/cgi-bin...?&I=LXZZZ3&P=7




Buzz.

RE: Constellation to go electric.....
 

Should i use separate batteries for powering RX to run all servos or these will do the job, not to forget adding more weight will be crtical on electric models unless being 4 engined model, its not that big of an issue...

Secondly, does pitch of prop differs amp draws from ESCs or it doesn't matter...sorry if this is stupid question but as i newbie into electrics, i asked this....

RE: Constellation to go electric.....
 

On a model this size, I am not sure a 6 ounce battery pack would make much of a difference. Could save almost that much weight by changing from rubber tires to foam tires.

I have 3 of these and they work very well.
http://www.hobbypeople.net/index.php...jr-z-conn.html

You could always use a UBEC with the lipo battery.
http://www.hobbypartz.com/ubube.html

Yes the pitch of the prop will change how many amps the motor draws. Lets say the 13X8 prop draws just a little to many amps for the motor to handle. Going with a 13X7 might bring it down to the safe range.


Buzz.

RE: Constellation to go electric.....
 

Buzz n others:

How many UBECs do i need with my set up and then will i be able to fly my model on single receiver or would 2 receivers is the way to go?

I know it's getting complicated here a bit but i need to know how i can set up my model that will be safe and i will have full authority on it while flying it.

Presently motors and Esc's are on back-order list and until i get confirmation email from HK for them available, i will not buy them till that time.

RE: Constellation to go electric.....
 

Me, I like simple so I would go with a single Rx and a Single UBEC. With the UBEC, get the highest amp rating you can.


Buzz.

RE: Constellation to go electric.....
 

Ok, thanks Buzz.

I like to keep things simple too, i wasn't sure so i asked.

So it means, 1 UBEC is used per RX on the model, so if anyone is using two RXs then they will need 2 UBECs...


Sam

RE: Constellation to go electric.....
 

That is the way I would do it. If I was really worried I would use one small 3s lipo, UBEC per Rx. That way each Rx has it's own power source. Sort of the way the giant scale guys use two of everything.

Buzz.