Electric conversion ?

Here is the accu/battery ; http://www.hobbyking.com/hobbyking/store/__8586__ZIPPY_Flightmax_5000mAh_6S1P_25C_.html I have no idea how it takes to stay airborne as for now. Here is the engine; http://www.hobbyking.com/hobbyking/store/__14427__Turnigy_CA120_70_Brushless_Outrunner_100cc_eq_.html It won't quite beat the Fournier Fr-4 in power to weight ratio; http://en.wikipedia.org/wiki/Fournier_RF-4 But is level with ASK-14 ; http://www.sailplanedirectory.com/PlaneDetails.cfm?planeID=17