What motor for a GWS F-15

[eran_k]

I'm looking for a powefull setup for the GWS F-15 (twin 64mm fans)
what motor from the wicked range will be good for a 4s setup?
how about the cool wind 4000kv? are there adapters to fit it in the GWS fan?

Thanks
Eran

[The Don]

I flew mine on the Wicked 4800s with two 3S2200 lipos. That is about 650-700 watts on that setup, it is over 1:1 thrust to weight and is a good flying model. I actually clipped my wings 2" at the root on each side.

Here is a photo in the GWS thread I posted:

http://www.rcgroups.com/forums/showpost.php?p=8869466&postcount=657

I used the stock 3mm GWS rotor adapters.

Don

[eran_k]

Thanks,
But say i want a 4S setup,would the 4000kv work better?
and does the motor fit direcltly to the fan adapter? dont you need some kind of |-| adapter to hold the outrunner?

Eran

[The Don]

For 4S you want the Wicked 4000 motors with the standoff adapters. However, the problem is that the GWS EDF64 rotors will blow apart at the higher rpm of 4S. That is why I only went 3S on mine with the stock GWS EDF64 fans. For 4S you will want to go to a different fan like the Eflite 64mm fans that they include in their version of the F15. Then you would order the "Wicked 4000 motor with standoff adapter and XF plug" option on my website.

Here is the fan I am talking about:
http://www.horizonhobby.com/Products/Default.aspx?ProdID=EFL7007

This is a 3 blade fan and will be about 950-1000 watts for the two together on 4S.

You can also order one of each of these:
http://www.horizonhobby.com/Products/Default.aspx?ProdID=EFL7062R
http://www.horizonhobby.com/Products/Default.aspx?ProdID=EFL7062L

You will have to break off every other blade to make a 3 blade rotor.

Don

[cray2602]

I have decided on using your 4800kv motors in my GWS F-15. The stock GWS motors just arent enough oomph for me and i allready have one of your 4800kv motors on the shelf. From watching your vid it looks like it runs pretty good with this setup.

[eran_k]

I think maybe i'll give the 4800 a try too,how many amps will they draw on 3S in that fan?
do i need the standoff?
what's the biggest battery that can fit in the f-15?

Eran

[cray2602]

I use a 3300mah 25c in my F-15. You will have to hog some foam, but it will fit and it balances perfect. Don can tell you better than i but amp draw on the 4800 motors should be around 30~35amps per motor, or 60~70 amps combined. You do need the standoff adapter, and the GWS fans i believe use a 3mm shaft adapter which will fit the 4800 motors.

[The Don]

You beat me to it :) Yep amps will be about 30-35 depending on the lipo and for the GWS you need the standoff as the motor diameter is too large to fit into the housing. The only fan that will not use the standoff adapter is the SF fan.

Don

[cray2602]

I swapped my stock GWS motors for a pair of your 4800kv motors in the F-15. Im pulling 54amps combined. Seems a little low compared to your numbers. Fans are balanced and my battery is holding up fine but i do have some cheapo Towerpro ESC's installed. Could junk ESC's make that much of a difference in performance? I didnt want to change ESC's out cause it will take some serious work to get them out and install new ones. But if thats what the problem is ill try it.
Any thoughts on this?

[The Don]

I swapped my stock GWS motors for a pair of your 4800kv motors in the F-15. Im pulling 54amps combined. Seems a little low compared to your numbers. Fans are balanced and my battery is holding up fine but i do have some cheapo Towerpro ESC's installed. Could junk ESC's make that much of a difference in performance? I didnt want to change ESC's out cause it will take some serious work to get them out and install new ones. But if thats what the problem is ill try it.
Any thoughts on this?

The ESCs can be a cause as they eat some of the power. Cheaper ESCs have more resistance so less power goes to the motors. What voltage are you getting under load?

Don

[cray2602]

My battery settles in about 9.5volts under a 30 second WOT run. Thats lower than i remember from the initial runup, so that could be part of the reason. Would one more volt from the lipo and higher quality speed controllers make that much difference?

[The Don]

9.5 volts is definitely the culprit. An average 3S lipo under load should be around 10.8 volts or so. That extra 1.3 volt is a big difference. I would change lipo before messing with the ESCs. You may be perfectly fine. I ran two 3S2200 lipos on my GWS F-15.

Don

[cray2602]

I have a pair of 3s 2200 25c lipos but i couldnt find a way to mount them without getting very creative. I will parallel them and see what results i get.

[The Don]

I had both lipos in the cockpit, one after the other. I remember hogging out foam to do it.

Don

[cray2602]

Hey Don.
Something else i thought of, i am using the GWS extension wires that run from the motors all the way up front to the back of the cockpit where my ESC's are located. Those extensions are rather small gauge wire and really long. Is there a chance that i am trying to pull too much current through those wires and loseing some oomph there too? I have read that it is better to have long motor wires rather than long battery wires, is that correct? I hate to gut and rewire this plane completely but that may be what it needs.

[cray2602]

Well i tried the motors out in my SU-27 with GWS64 fans and CC Phoenix 35 ESC's. Holy *****. My lipo hit LVC at 60amps, on one motor it peaked at 40amps. I got 1000 grams thrust before LVC, and that was with my exhaust ducts not even sealed off. With a good Lipo this thing will be killer. I think the junk ESC's in combonation with long battery and motor wires was chokeing the motors on my F-15.