Had again a really nice saturday flying with my Hashcopter. Took first images from the copter with my 800 gram camera. Pictures didn't turn up to be anything spectacular but copter flew nicely at high altitude and was very controllable. I'm still waiting for parts to arrive for my camera stand and FPV equipment. For that reason camera stand was just taped to nice position and images shot by feeling.
I actually had some difficulties with cheap ESCs not arming the motors properly. This was due to it being -25 degrees Celsius temperatures and electronics just needed some warming up occasionally. Actually so did the pilot. Eventually one of the ESCs broke down and flying was over for the day.
Because ESCs did some tricks on me I accientally ended up testing what happens when one of the motors shuts down. I was landing the copter still hovering at around 20-30 meter height when one of the motors just stopped. It was nice to realise everything was still controllable and I was able to land to copter nicely to a snowy field. It could have been flown with just 7 motors despite the heavy camera hanging under the copter.
All saturdays pictures with better resolution:
http://www.markusjahn.net/gallery2/main.php?g2_itemId=47419
Previous two parts of the story:
http://www.diydrones.com/profiles/blogs/weight-testing-of-8-motor
http://www.diydrones.com/profiles/blogs/arducopter-quad-with-eight
Comments
There is also one positive side more on twin battery setup. Even when flying with 25C battery current with eight motors is so big that when flying the battery down to 3.7 volts it warms up. With two batteries you might avoid this phenomenom which wears down batteries.
About saving a falling copter I wouldnt count much. Hashcopter can survive a motor failure and ESC failure and I don't believe batteries ever fail suddenly and totally... Of course learned that anything can happen when you are flying. :)
http://www.markusjahn.net/gallery2/main.php?g2_itemId=47664
I too consider this to be best way to make eight motor frame. It is a bit heavier than the type with arms attached to each other with two center plates. It is also little stronger and that pleases me when flying with heavy camera.
About the evenly spaced motors in a circle shape I would say don't change it. For some reason it makes the copter more stable than any other shape. The 83cm diameter comes mostly from the fact that it is still fits to my car and can be transported more easily.
My ESCs and motors are from RCTimer and I am quite happy with them despite one ESC is broken right now. They are 11$ ESCs and 10$ motors so if one breaks I'll fit another. No trouble...
Running 4S 5000mAh 25C batteries. Frame is bolted through the lower bar and top bar has access holes on top bar(it just looks better). Same bolts also attach the "legs" to the frame. I put couple more pictures on the build page where you can see middle part of copter:
http://www.markusjahn.net/gallery2/main.php?g2_itemId=47667
http://www.markusjahn.net/gallery2/main.php?g2_itemId=47658
http://www.markusjahn.net/gallery2/main.php?g2_itemId=47661
There are no hidden spacers inside tubes, just bolted through. The top bars bottomface and leg work as washers keeping the lower bar in shape when tightening the bolt.
My props are Graupner E-Prop 10x5. They are strong props but propably bit less economical that Arducopter standard/Maxxprod/APC propellers. As you can see my prop savers are quite rough. But that is how I want to make my copter. If simple things work there is no need to change them:
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