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Mar 30, 2007, 02:15 AM
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Nothing sticks to balsa


The biggest problem affecting Coptershyna is the inability to stick things to balsa. We have really flimsy tape bonds between sensors and PC board, GPS and electronics table. Can't use aluminum because it's expensive and heavy. Carbon fiber is even more expensive.

The last component, the GWS gyro, requires attachment to balsa. Routing long wires from its station on the fuselage to the computer would be heavy. Drilling more holes on the electronics table would weaken it. Most likely going to need a rate gyro implementation on the Gumstix, a very risky path.

Really wanted no modulation of the flight controls unless the autopilot was enabled, but a synthetic rate gyro is required to fly it manually.

So if we record flight data on the flash in flight, it's likely to occasionally freeze up the kernel on a write, a lethal condition. Minidisc isn't fast enough to record it over wireless. All roads lead to recording to RAM and flushing RAM buffers after transmitter shutoff. Unfortunately it means only 1 recording per flight.

After a major firmware update, when the rotor is locked & loaded, and you plug in the main ESC power for the first time, your future on this planet, every experience you ever had, every limb you ever had, is in Coptershyna's hands.

No problem with the throttle this time, fortunately.

Quite a relief, after weeks of that malfunctioning GWS, to have Coptershyna back in charge of the RF, but the GWS is still malfunctioning, causing complete loss of signal with the CRC checking. Not a termination problem after all.

Full servo deflection can cause the blade to hit the GPS but this has never happened in flight. Need to reduce servo deflection anyways.

Not getting a Coptershyna greeting from the firmware during startup anymore and she doesn't flush the flight recording properly. Booting from the command line is required for nominal operation.

Synthetic tail gyro is coming along. Currently sampling for 10 seconds to get the center position and updating yaw offset at 5Hz. Suspect the GWS rate gyro had serious downsampling to overcome vibration.
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