F5J rules

No limit on size or control functions.

Power System
Direct drive motor (of any type) with a published weight of no more than 68 grams.

3 or fewer LiPo cells (any capacity)
9 or fewer NiCd or NiMHy cells (any capacity)
3 or fewer LiFePO (a.k.a. LiFe or M1) (A123 or other manufacture)

Man on Man in a 10 minute round (Working Time 10 minutes)
One unlimited continuous motor run
Flight time starts when you stop the motor
Landing in a 15 meter diameter circle yields 30 points
Landing after the 10 minute working time ends yields no landing points.
The power system will work well in sailplanes from 1.5 to 2 meter, or even larger if built light.
Suitable power systems for this class (motor, ESC and battery) are now very inexpensive.

Some motor suggestions

Good Quality
** Hyperion GS2213-16 http://aircraft-world.com/shopexd.asp?id=5166
Scorpion 2215-18 http://www.innov8tivedesigns.com/product_info.php?

KDA 2215M http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?
Add a 25amp or more speed control and a 1000 to 1500 mah high C rated (30C +) battery

** Note: Motor and link changed