10 January 2014
First flight. Everything was going so well.....
This post is part of a series: Designing a Mapping Robot
In the last point I talked about assembling the quad copter and lifting off for the first time in my basement on a tether. This is all very exciting but at some point we're going to have to get it outside and flying.
I glossed over the camera we used in the last post but I think it bears some mention now since I'm going to be including a lot of footage from it.
Those of you who have spent a bit of time watching flying copter videos on youtube will not be surprised that we decided on the GoPro Hero3 Silver edition. It's a tiny low-cost, HD camera that comes with a rugged, waterproof case. At the time of writing this there are maybe 1 or two competitors but basically it's the gold standard of sports photography. The camera has a time lapse mode which we will need for our photogrammetry and mapping later (hang on, we're getting there).
The first flight was really not that exciting from some standards. I and some friends went to a park and then I turned it on. The following video shows what happened.
What you don't see is when I crashed it. BAsically it was flying too close to the sidewalk and I brought it down to avoid getting near people. The crash was tiny and the copter only fell about 2 feet but it still bent the frame and shattered one of the rotors. This would be the first clue that something was wrong with my choice of frame.
The second flight was more (and also less) successful. Philip and I went to a nice park with lots of room and nobody around.
When it came down it shattered pretty much everything carbon fiber piece in the frame, bent two of the aluminum pieces and wrecked two of the props.
I know that this wouldn't happen as often once I learned how to fly properly but our mapping robot is going to be expected to fly out in nature which has rocks and trees and water. Clearly a carbon fiber frame is not going to cut it.
The Turnigy talon 2 frame is a very light and inexpensive frame considering that it's composed almost entirely of carbon fibre but it fails in a number of important respects:
Carbon fibre is brittle. If your copter falls from more than 3 feet (and it will, trust me) then you will need to replace parts. This will get expensive fast. The aluminum pieces have a large, flat, unsupported segment that bends really quickly. This strikes me as a design flaw and I think I can do better. Too many screws in all the wrong places. To replace a shattered arm you pretty much have to take apart the whole frame. Juggling dozens of tiny screws while you're outdoors in the rain will quickly become one of your least favourite things to do. In the next post: Makerbot to the rescue!
- Building a 3D mapping Robot 24 June 2013
- Quadrotor Shopping List 28 June 2013
- Assembly and why Flying indoors is a bad idea 30 June 2013
- First flight. Everything was going so well..... 10 January 2014