Part 2 in an ongoing series about being a good test pilot. These articals are less about step by step hand holding instructions and more about how to think. We continue….
I always conduct an interview of sorts to fill in the blanks of things I may not be aware of such as level of experience, how long the project took, what the MFG says about CG location, suggested weight, what does it actually weigh and etc…. What your fishing for anything that could be a surprise. After the crash, you don’t want to hear the builder say “I thought 1/2″ behind reccomended CG was close enough?!?!”. Your looking for any shortcuts or oversights in the model. Did they use the reccommended servo’s or at least close? Is the battery large enough? How old is it? If the RX is new, has it been run a while? If the RX has come from another model, was it flying fine or did it’s last flight end in a crash? Has the TX been performing well? Are there any used or harvested components in the systems?
Always check the CG against common sense and what the builder says it should be. NEVER trust that it is right. Hold the model up in the air and check it yourself. Measure if you must. There is NO excuse for crashing over a missed CG check.
Control surface throws: I’ve run into many first time builders that started with a few foamy’s, have built their first sport or scale model and they put throws in the model that look like the 3d foamy they’ve most recently been flying. Not realizing the throws apropriate for a 25-30mph ship will be grossly excessive in a 70mph aircraft. Besides asking about suggested throws, apply your own stink test. If it doesn’t look right, it probably isn’t right. I like throws for a test flight just a tad on the high side of suggested first setups. However, you can take this way too far and end up with an over sensitive model. A model that is way out of trim and also way too sensitive is a real handful. Don’t walk into any such traps. Also, if a throw such as the elevator is too low and the model turns out to have an incidence or nose heavy problem, you might not be able to land at a reasonable speed and hold the nose up. Too little therefor can be just as bad a mistake. Try to be reasonable about what’s correct for “this” model. Generally, the faster it flys, the lower the throws should be. Something else to aid here is look for similar level of throws. If the ailerons are deflecting 30 degrees and the elevator only 15 degree’s perhaps the throws will be “out of balance”. Out of balance controls would be one control being sensitive and antoher being soft. This is more difficult to process in your brain when your under pressure trimming out a difficult model. Consider it before proceding.
To Be Continued……..