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Monday, November 17, 2008

A Story about Pre-Flight Checks

Had to take a break from building the P-51D - birthdays, family stuff and such. In the meantime, here's a little tale.

When flying radio control, I try to be diligent about pre-flight checks. However, a month or so ago, I came a cropper while flying the STARLITE (see photos).

Picture this: after changing the prop and replacing the battery with a more powerful plant, she was flying beautifully, save for a noisy (definitely broken) rudder servo. I replaced the servo, and while testing on the dining room table, was delighted that the rudder operated as quietly as the elevator. Charged her up and excitedly, went off to the field. Did my checks and launched from a throw. She climbed a bit then - spiral dived to the ground! I checked rudder centre trim setting, it seemed ok, so I launched again.


Painfully, she spiraled in once more, this time losing a leg and a suffering a bit of minor damage to the fuselage.

What to do? I checked alignment of all surfaces. Nothing except an ever so slight warp on the rudder. Surely the spiralling could not be from that? With the plane pointing ahead of me, I waggled the stick.

Then I saw it. The
rudder was moving in the wrong sense! I had done my checks the first time with the plane pointing towards me (and without engaging my brain!). It took 5 seconds to reverse the new servo from the TX switch, after which she flew beautifully (although now with one leg - fine practice for holding off on landings!).

When I first heard the story of the pilot who chucked his radio control glider off a ridge, only to realise he hadn't turned the receiver on and then watched it fly off into the distance out of sight, I used to wonder "how could that happen?". Now I understand! For me, repairs were cheap and easy but I hope the valuable lessons learned last forever
:

- Always take care over pre-flight checks. Do them PROPERLY, especially when excited about the flight.

- Never assume that a replacement servo operates in the same direction as the previous one. Check it!

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