Travel sickness

I took Phoebe to Cheltenham on Wednesday to check out the new location for the Cotswold Raspberry Jam (tickets still available but going fast).

Yesterday (Thursday), I took her out for a few more ‘confidence building’ test flights, and she was a changed quad – she climbed too fast and continued to climb during hover and she drifted significantly.  Oh sh1t – we have the perfect location to show her off, but somehow she was no longer fit to be shown.

Today (Friday), she’s back to behaving normally again so I’m concerned her accelerometer had drifted in transit to Cheltenham – while carrying the case, her Y axis was pointing down, sensing gravity and her Z axis was not unlike normal – that matches the drift I was seeing.  I hope that’s not the problem as that would ruin the chance of an indoor flight at the Jam – hopefully the weather will be good on the day, so at least an outdoor flight should still be possible.

Anyway, while trying to work out what was going wrong, I reviewed a couple of things I’d not done for a while.

The first is prop balancing – using my Dremel to lightly strim the underside of the props so that they have a matt surface, and they balance well on one of the maglev prop balancers.  The matt surface allows the air to flow over the props smoother which leads to better more efficient air-flow, and reduced turbulence resulting is greater lift.  For that reason, I used P1000 wet and dry sandpaper to matt and smooth both top and underside of the props.

Balanced blade

Balanced blade

The other is (controversially) to re-add 0g calibration but only on the X and Y axis – the primary directions of drift – in such a way it can be done indoors from a relatively flat surface prior to demo flights, but also can be disabled easily without the risk of coding errors with a destructive resultant flight.  Calibration takes half a second, and results are stored to file, and reloaded each flight; if the calibration is not possible, then the calibration file settings can be set to 0 to disable it, thus dropping back to Phoebe’s performance from the last few days.

I don’t think either of these were related to her travel sickness, though now done, there’s no point in undoing them again!

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