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Old Jun 01, 2010, 04:45 AM
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Joined Sep 2006
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Hey Metroid, Allready a while ago I finished the Spasatel for the first test runs. First I added the Brushless:



I placed two rate Gyro's, both lying on it's side, angled 90 degrees to each other:

(kinda hard to see:P)
By placing them like this they are both stabilising roll & pitch, both beeing connected to one of the elevons on the tail!

Servo's...


Then..it was ready for the first tests! They quickly revealed a design flaw, When the craft starts aquaplaning, the front Hull step also touches the water, which means the craft has two water contact points during planing, allthough the CG is located very near to the rear hull step.
Alltogether this means that as soon as the model starts aquaplaning, it is directionally unstable and does it's best to go anything but straight forward!

I changed this by adding a lager Hull step which also was located nearer to the CG, to reduce the nosedown attitude during aquaplaning, Plus by adding a small Aluminium fin below the tail:





The final model:


And...the next test run was higly succesfull. The model starts aquaplaning after a few meters and quickly accelerates. Without rudder input it keeps track and after 50-100 meters it starts to completely unstick from the water, no instability issues sofar!

After the second high speed pass, during "landing", the model started to slip sideways. I tried to prevent this by using opposite rudder input, but the model tripped over it's left sponson(float) and rolled over completely, ripping of its rear stabiliser.

Now I actually did pull of my clothes and jumped into the water, but it was kinda "too late".

Back on the dry I found the brushless outrunner beeing completely stuck, I couldn't turn it any way, probably some loose magnets! I then opened the electronics hatch and found that the broken Brushless motor had shorted out my ESC, which had burned out.

The Lipo was fine, the ESC and Brushless are trash!

The model is now standing in my room, at the moment I don't have the financial capabilities and the motivation to continue testing

Greets,

Marijn van de Ruit
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