This ratio also means that an unpowered hang-glider flying at a constant speed moves 15 metres forward for every one metre it descends .
这个比例也意味着一架无动力悬挂式滑翔机以恒定速率飞行时高度每下降1米，可以向前滑翔15米。
On a single charge it is capable of taking off and soaring to 3000 metres , though the same amount of energy could also be used for multiple launches to a lower altitude , or for range-extension during a mostly unpowered flight .
