Rhilluk

anyone had any experience of these motors. Or should I buy an Axi or Hyperion

tIANci

Foody ... I bought a few and used one and it was not a good experience. Firstly, the prop adapter was not drilled deep enough, so the bolts will not sit flush, your prop will not be level. I had that on 2 motors. One of the motors had its magnet detached when I powered her up. Many complained about such problems when the motor is pushed hard but of late some feedback is that the motor is muach better. I have read reports that some users drip CA onto the sides of the magnets to keep it in place. If you will be pushing the motor hard then get a branded on like Hyperion or AXI etc. DualSky motors in the 42XX range or below are pretty good, I used quite a few.

Velco

My experience with the regular "golden" series is better than with the SK series. I have (had) 5 smaller ones and 2 larger ones. The larger ones I have replaced with Hacker, sorry I don't trust the magnets even after putting CA glue.

On the smaller ones no problems with magnets but shaft is relatively soft. The bearings are not of the highest quality either and if the prop is not absolutely  perfectly balanced u will have problems with them.

On the other side 4250-700 and 4240-1050 are performing very good in Element 30 and Acromaster.

Just don't push it to the max power suggested by HK, up to 70% is fine.

Where do you plan to use this motor, may be I can help you choosing a better one?

Rhilluk

I've got 40 size aerobatic model I was looking to put it in. Weight without motor - battery and esc should be 1.5lbs - 2lbs

Velco

OK,

lets presume it is 2lbs = 900g empty, just to be on the safe side. We can now presume a total weight of 1400-1500g =3.3lbs ready to fly

To determine my initial setup I always first visit AXI site http://www.modelmotors.cz/ as there is a very nice tool: FAST AXI SETUP , you can find it on the right hand side of the home page.

In that tool you can now choose type of model (in this case aerobatic) and the total weight on take off (in our case 1500g). Lets click on FIND SETUP, the tool now suggests various AXI motors, and as I always prefer to have more reserve of power than AXI suggests I would take 2820/12 which is good up to 2000g aerobatic. The suggested battery in this case is 3S, 40A ESC and 12x6 prop. I do agree with bat, but would take a larger ESC (60A) and the prop is OK. Also by selecting a slightly larger motor you do not need to push it to the max all the time, a lot of benefits for only very small gain in weight.

Now If we want to get an AXI motor we are fine, but if we don't want an AXI what have we learned from this? Any other motor of this size (equal diameter and weight) with this or a kV within 5% difference will be OK. So now we can go and choose whatever we want, Hacker, Scorpion, Turnigy, Hyperion ...

And what battery size: well, the weight is really of big importance only if you plan serious 3D, otherwise some grams extra do not hurt that much, so I would go for something like 3000-3500mAh and at least 25C. Always buy 2 at the same time as may be tomorrow you might need these bats to be used as 6S, but about this at some other occasion .

tIANci

Foody ... decide what size packs you want to work with ... 3S 4S or 5S. That makes a difference. Think of medium term too. Do not get it just for the current plane, if the plane is gone where will the power system go into net. With that in mind it helps you decide what you may want to own.

Rhilluk

3 series seems a bit low. I think once I have finished the model and can get an acurrate weight I will decide then.

Currently with the wings and fuse all together it is weighing 1lb. Thats without the covering and radio etc.

Velco

tIANci is absolutely right, we should always think at least one step ahead concerning batteries.

For this application (F3A type of flying at 3,3lbs) 3S is more than enough, or better said 500W is more than enough and that is 50A on 3S bat. If you get 3S with 3000-3500mAh capacity you will be able to easily connect 2 of these batteries into 6S for a plane of up to 6,5lbs without any problem.

I like to overpower my planes and on a very similar model you plan I have a 4250-700 on 4S 30C 2650mah spinning a TGS 12x8 prop up to 9000rpm (2,5kg thrust and 110km/h max speed) at 53A, and it is a rocket! i do not know your skill level, and if you are not at least intermediate it will be too much. The only problem is that these batteries can not be used on any other of my planes.