Practical difference?
 

what is the practical difference between these 2 motors?

http://www.aircraft-world.com/prod_d.../z3019spec.htm

it's for a sailplane (CMPro Discus 1.6m)

thanks

RE: Practical difference?
 

The practical difference? Hmmm ... let's try this. We assume that you will use a fixed amount of cells for the motor. For this reason we say its perhaps 10 cells.

1. The 3019-12 will turn a bigger prop than the 3019-10.

2. On the other hand, you can always use the 3019-10 with less cells to turn a certain prop compared with the 3019-12.

3. If you want some speed then take the 3019-10 to turn a smaller prop at a higher RPM. Whilst the 3019-12 will give you more thrust with a bigger prop.

I hope this helps. :)

RE: Practical difference?
 

The practical difference is the number of windings on the stators. The more windings, the lower the KV, the slower the RPM, the bigger the prop for the same amperage draw.

I'd estimate the AUX with power system to be about 3lbs... to shoot for 100W/lbs should pull it nicely.

the -10 model charts out with a 14x7 prop using a 2S LiPO (Thunderpower Prolite 2100 w/ a 40A speed controller - don't spend much time over 1/2 throttle or you'll need to goto a bigger battery)

the -12 model charts out with a 10x5 prop using a 3S LiPO (Thunderpower Prolite 2100 w/ a 30A speed controller - this setup you can fly full power the entire flight if you'd like... still check and see if things are getting warm)

I don't know anything about folding props, but you may need to experiment to get the 300W draw. I think for such a large plane, I'd favor the bigger prop, but I think either would work.

RE: Practical difference?
 

Philosophy. I'm in the more volts less amps camp myself. The 900 Kv motor should turn a 10 inch prop with 5 cells very nicely, peak at about 400 watts. You have to think about things like: prop size, how many cells will fit, flying style, desired flight time.

RE: Practical difference?
 

so would HP-Z3019-13 be even better than HP-Z3019-12?

I don't have info on the -13 but it is available to me.

RE: Practical difference?
 

Vasek ... you cannnot say which is better, they are made for different applications. Example, I got the AXI 2826/12 ... most will use the 2826/10, I chose the 12 turn because I wanted to use 4S and turn a bigger prop for a 40 sized plane. So that works out for me. Others may fly something slightly smaller and they wanna go fast on only 3S so they will go with the 2826/10. Some of my motors are with a higher number of turns so I can use a bigger prop or more cells and some less turns so I can push it hard for speed on less cells.

You need to see what your application is. Are you going to go with lipo? What sort of packs do you want, i.e. how many cells 3 or 4? I seen those DLG type of gliders flown on 2S but the motor is a really high KV one.

From what I can remember the CMP Discus will carry 4S packs of up to 3,700 mAh with ease. Like what Dave has posted you have to decide what sized packs, does it fit, flight duration etc.

RE: Practical difference?
 

so would a 3s (1800) and the HP-Z3019-12 & a 12x6 be a good combo?

I do not understand the various numbers for specific props[:o]

Thanks

RE: Practical difference?
 

Vasek ... I may be wrong but I doubt that the 3S 1,800 packs will be enough for the Discus. The plane is 2.6M and should be no less than 5 lbs. If you wanna cruise around you will want a system that pulls 100W/lb. That means you want to push the packs to 50A for the lift off. Your packs will die fast. I would go with 3,000 mAh packs or run on 3s2p, giving you 3,600 mAh. for me I will want to turn a nice big folding prop of about say 14" for that plane.

Are we talking about the same CMPro Discus?

RE: Practical difference?
 

yes same Discus...

there is a Japanese guy flying this setup wit the HP-Z3019-12:

prop; Aeronaut 11 × 8 Folding

power; Polyquest XP 2500-3S
(Or, enLipo BLACK 2100-3S, Hyperion LVX-3300-3S)

RE: Practical difference?
 

If that setup works well for him, then copy it. With a glider, I'd assume you'd rather spin a larger prop to get more vertical performance for an easy hand launch and good climb rate. The lower Kv motor (the -12) will spin larger props. The only reason to get the higher Kv motor is to spin smaller props and get more speed.

RE: Practical difference?
 

Vasek ... well like what pkh says, if you like how the Japanese dude's plane flies then go with the same set up. We have one at our field, its a twin 70mm EDF, a 3S set up ...

RE: Practical difference?
 

Thanks for the info guys!

V.