Mini Heli - a marvel of micro engineering

About 3 months ago one of the engineers from work brought in his miniature helicopter and drew quite a crowd in the office. A couple of weeks later we each had our own (thanks to eBay ~$20) and have had heaps of fun. They are quite resilient and simple to repair (I've been doing a fair bit of that). This week another engineer brought his 'combat helicopters' in. These each have an infrared transmitter and reciever, where the goal is to 'shoot' the other chopper out of the sky. When a chopper registers a 'hit' the engine stops and it falls to the ground. So far I have 3 kills and have only been shot down once. This was originally an idea we had for our final year engineering project - using planes. We had a couple of things working against us - only one plane, and only one pilot - the UAV project turned out to be somewhat more practical.