Centre of Gravity
Words & Images Geoff Raebel
We all know that for flight stability, the Centre of Gravity needs to be within given limits to enable a pilot who has in-inadvertently got into a spin - to recover.
It can also be important on the ground – I once found to my cost.
I had inherited my dad’s 95.10 VW powered Winton Brumby. My Dad had shown me about running the engine with the wings-off.
At The Oaks one day when it was too windy for anyone to fly, I decided to check the plugs and ignition (coil) points. Once done, I hand-started her and standing by the throttle, let the engine warm through. A Club member started walking toward me calling out something, distracted, I tried to understand what he was saying, then read in the faces of onlookers, that something was wrong. Too late, I turned to see the tail going up and over and the propeller grinding to a halt in the dirt with one splintered blade.
What went wrong? I was on a steep learning curve with my first aircraft. Without the wings or pilot the C of G was well forward. It didn’t take much of a gust to get under the tail to upset the aircraft.
How could I have avoided it? I now know the tail should have been tied down to both avoid the tail lifting and to stop it jumping the chocks. Oh, and the dangers of being distracted when operating a dangerous machine!