destined2nate

i've just finished covering my herr breezy day cub and i want to go brushless but this is my first plane and i have no idea how to approach powering it.the plans call for a 280 direct drive but i want to go brushless...any advice is appreciated.


here's a few pics of the plane

Matt Kirsch

My Feedback: (21)

The Eflite brand is great for newcomers in situations like this: A Park 280 outrunner is intended to be the brushless upgrade to a 280 brushed.

Dr Kiwi

Does a Park 280 exist?

Since a wimpy but heavy (41g) 280 brushed motor in direct drive can only manage <20W on 6v with a 6x4, for <$6, something like this will weigh less (37g) and generate a lot more power (60W-100W): http://www.hobbycity.com/hobbycity/s...idProduct=5427

There are probably several HobbyCity motors which weigh under 25g which would do the job too.

destined2nate

thanks for that link!

gboy333

PLease - how do you manage picking a brushless out runner amongst all the package data?...numbers letters , ect. I am trying to up grade a p51 currently with a 370 brushed..
the choices just look , like too many to dijest. Yes I am new to rc flying, but have got the bug!
thanks to all!

gboy333

To all - I am trying to up grade a 370 brushed in a p51 +- 14oz. I am new to rc flight but have the bug. The letters and numbers associated with brushless motors are tough to dijest. How can I pick a brushless replacement/upgrade without a voteck course?
thanks

Dr Kiwi

Take a look at the power requirements - at 14oz 80W-100W would be plenty (~100W/lb). You need a relatively small prop for a fast plane of that size, so you need a reasonable Kv (say, 1300-1500) to spin a 7" prop. The motor I linked to above would be okay, though a slightly higher Kv, lighter motor might be better. Something like this well-regarded Blue Wonder (1500Kv version) with maybe a 7x5 APC E: http://www.hobbycity.com/hobbycity/s...idProduct=4859

gboy333

Dr Kiwi - Thanks a mill for the info. Im hearing 100w requirement per lb of plane weight. Got that.
Im flying a Parkflyer p51 (actualy 16-17oz) and its a challenge but quite rewarding. The props that came with it are a 10-4.7, and a 9070. The latter seems to provide more speed which keeps the plane from squashing out and "rolling off the ball". I was told the 10-4.7 was a "tractor" prop, which is slower and not as smooth, harder to fly. This model needs more touch the slower it goes, so I am looking for smoother and faster.
Now the kv factor 1300-1500, what does that refer to in the mix, and why higher?
APC E, whats that ? and 7x5 is your sugestion for matching prop size.
So...today I replaced the original brushed motor with a Chinise 370 brushed replacement. Ran great for 12 seconds, surged a few times,then quit. All other servos are still OK. Your thoughts?
Thanks again.

Dr Kiwi

Okay, so we need a larger prop than I had first thought, so lower Kv - it shouldn't be to hard to get 150W with a 9"-10" prop, to get you plenty of power.

A 70g Suppo A2217K/9 (950Kv) on 3s gets you this:

9x5 GWS HD: 10.9v, 11.95A, 130W, 9000rpm, 42.6mph, 808g, 28.45oz, 6.22g/W

10x6 GWS HD: 10.8v, 15.10A, 162W, 8340rpm, 47.4mph, 938g, 33.03oz, 5.79g/W

You could certainly try a 9x6 to get a bit more speed. Of course whatever you choose you need a pack which can deliver the amps your motor/prop requires.

Check with Dave at www.lightflightrc.com.

Cheers, Phil