Brushless like-for-like replacement for brushed 380 motor?

[aesmith]

Hi,

My plane (a cheap electric glider) uses a 380 brushed motor. What would be an equivalent in brushless? I would like to replace it not specially for more power but because I need a new ESC in any case and it doesn't seem that sensible to put more cash into old technology. The existing motor turns a 6x3 folding prop and runs off a 9.6v NiMH pack. The plane's flying weight is around 650g.

I'm hoping that a "380 motor" is pretty standard, and someone can tell me what that would mean in terms of Kv, amp and watt ratings that brushless motors use. With that info I can see what looks suitable from my favourite budget supplier (Giant Cod).

Originally I hoped I could retain the existing prop, but I guess the shaft size is unlikely to match so I might have to replace the hub anyway. Even if that's the case, the plane really suits a small prop for low drag when folded and to minimise chances of damage on landing, so I guess that means a high-speed motor.

Thanks in advance, Tony S

[Roger]

380 or 400 sized motors are still around, unfortunately from what I am aware, there were more than one type. If you do a google search for speed 400 motors you should find a fair bit of information around. If you have blown your speed controller, then you might be surprized to find that you can very easily pull a lot of current with such a small motor, however you want to be careful as they will konk out if you pull much over 20 amps with them.
From my understanding of your model I would guess that you have the 7.2V version of the 380 (more or less the same as the 400) - these motors are all 28mm diameter, and on 8 cells turning such a small prop, you would probably be getting close to 19000rpm at full power. Have a look for a Brushless motor of the same diameter and a good suggestion is to get a speed controller with at least twice the amperage rating that you think you will need...
Good luck!
PS, I fly gliders (I've had electric ones too ) so take what I say with a dose of salt...!
Roger

[aesmith]

Cheers. As I say I need to replace the ESC, but its not because its blown up .... its because I want spoilers!

Spoilers means separate aileron servos, which means a different receiver, and my existing ESC doesn't work with normal standard receivers. Amazing how it all escalates, at this rate I'll end up having replaced all the electronics and power train.

[matwelli]

Whats your options for mounting the motor, there are many available and I am sure we can narrow down the selection. Do you intend swapping to Lipos at the same time ? or staying with NIMH batts ? it will make a diference in which motor will work best
Once we have nailed a suitable motor, then need to look at the size ESC needed

Intial guess would be a high kv inrunner such as an emax from Canebury Sailplanes http://www.flycs.co.nz/index.php?page=s ... &Itemid=55

[aesmith]

Hi, thanks for chipping in. The motor needs to mount inside the nose, screwed to a flat plate at the front, with the motor behind the plate inside and the prop shaft sticking out through the front. ie the opposite way round to most Outrunners that want to mount in front of a firewall. A photo of the existing nose should clarify what I mean ....

http://i42.photobucket.com/albums/e320/ ... edited.jpg
http://i42.photobucket.com/albums/e320/ ... edited.jpg

Ideally I'd stay with NiMH at the moment, but make sure the new ESC is LIPO compatible.

[matwelli]

Ahh, now I see what you are doing

This motor http://www.hobbyking.com/hobbyking/stor ... 2040_(130L)_2080kv_Brushless_Inrunner&aff=95764

This ESC http://www.hobbycity.com/hobbyking/stor ... Controller

and a 6 by 4 apc E prop and prop adaptor should see you going in the right direction.

Some outrunners can have the shaft reversed to mount the way that you need, but then you have a rotating can inside the nose of your plane that you need to keep the wires away from