It is in the nature of R&D that sometimes things don’t go according to plan. Sometimes they fail pretty spectacular. Last weekend was one of those times, when we lost control of our main airframe (the Bushmaster) during a normal flight and it subsequently crashed into the ground nearby.
Fortunately, our flight logs survived the crash (though microSD cards are a pain to find in a 25x25m patch of grass!) so we were able to look for a cause of the crash. It was found that the battery supply power to our servos rapidly went flat during the flight, leading to zero control of any our the flight control surfaces and throttle.
There are two possible reasons for this:
- A short circuit in one of the servos rapidly draining the battery
- The battery (being of the NiMH type) not being able to hold enough charge for the flight
Over the next couple of weeks we are going to make a number of changes to our hardware, software and procedures to reduce the chance of this happening again, whilst not introducing any extra points of failure in the airframe.
We will be busy building up a new airframe too!