UAG,
laudable goal to upgrade this engine, but lets look at what it would take for you to pick out your next motor so you know "why" and maybe even "how", for the next plane.
- Find your limits:
What are your limitations? Since the A5 airframe is picked, the motor mount is limited and the airframe dictates the prop can't lengthen by much (or at all).
- Use the limits to define a plan:
unfortunatly, since the prop is the more significant limiting factor, you'll need to consider that first. To get more power into the air, from the prop side, you need to either:
1. lengthen the prop
2. slow down the pitch (more pull, less max speed)
3. turn the prop faster (as long as you don't turn it too fast).
well the first two are out -- you can't make it longer and you want both more pull and faster.
Now option 3 makes things tricky. If the A5 was using a 2 bladed prop, it would be easier . . . but it's not. Spin it too much faster and the 3 blades will be eating the prop wash of their nearest neighbor -- robbing you of power. that means we need to switch to a 2-bladed prop spinning *MUCH* faster.
- Use the plan to define your search
What you have is a low KV motor swingin a 9" prop, So, what you are looking for is a medium-to-high KV motor capapble of higher wattage/amps. It'll also need to swing a standard 9" prop or smaller (at max wattage), with a similar motor diameter.
Specs for the park 480 1026kv (no specs for the 960) show a *burst* current of 28v, which gives you a rough guess for absolute max wattage on a 3S -- around 350W max. So you're looking for something in the 1300-1700 kv range, that can pull between 350-400w or 28-32A continiuos, has a 35mm diameter, and works well swinging a prop smaller than 9".
Quick glance at hk's site popped up:
http://www.hobbyking.com/hobbyking/store/__18157__Turnigy_Aerodrive_SK3_2836_1500_Brushless_Outrunner_Motor.html
Dead center of medium Kv, a bit smaller diameter, but higher wattage. I've bought a smaller aerodrive before, and liked it, but YMMV. Don't like that choice, you know what you're looking for!
BTW, keep in mind, you swing a prop faster and the same pitch will yield a higher speed (proportionally). So at 1300kv, a 9x6 will give you the same speed as the 9x8 at 960kv -- a 1500kv motor will give you more on 9x6!
I blazed through that pretty fast -- if something doesn't make sense or doesn't look right, feel free to ask (I've been wrong befo . . . actually, frequently.)