Being a Good Test Pilot: Part 4, Trim Pre Flight – Flight Plan

Our series about becoming a solid test pilot continues…..

Make sure every surface is perfectly nuetral. No slight rudder, or aileron inputs. Check the elevator for “slight up”. I would define this as the elevator being set dead nuetral then putting in about 1/32″ up or about 3 clicks of up trim. It’s always easier to control a model that is climbing too much than to fight on that is diving for the earth.

If we’ve done our job correctly, the model should fly well without any big surprises. We need a flight plan. First, how do we deal with an out of trim condition? If the model is badly out of trim, the two most important things to you are altitude and hang time to make the adjustments. You gain altitude by powering up to 100 feet at a minimum before you start trimming. I like to deal with the elevator first, then the ailerons. I am thinking of giving myself the best possible time to deal with the model. If it’s trying to pitch into the earth, constantly, you want to deal with this first. Be ready for it to climb too much as we started the flight out of trim to the upside on purpose. If it’s only a few clicks off, put the clicks in. If it’s a bunch more than that, slow down a bit, this will give you more time to input the elevator trim. Likewise, if the model is rolling to the right or left, start clicking in trim until it’s neutral. If by chance it’s rolling aggressively, to one side and you fell under pressure to get the adjustment in quickly before the model rolls over on you, try slowing down a bit, putting the model in a slight climb and rolling to about 45 degrees opposite the direction it’s out of trim. By doing so, you give your self a little hang time to get the adjustment in. I’ve seen models crashed because the pilot was a bit over his head with the model badly out of adjustment and they just kept fighting it without ever thinking to slow the model down.

Once we get the model in trim, the first act of business is to climb higher, perhaps to 200 or 300 feet. Do a couple of transitions into a stall, in effect a simulated landing 2 or 3 mistakes high. We want to get a fell for what speed the model is going to stall at and if it has any nasty snap tendency to one side or the other. Do this high just in case. Once you feel comfortable you can land it, fly a few figure 8’s to get a feel for control balance and rates.

By now we should be at around the 2 minute point in the flight. Land it and inspect for excessive motor/esc/battery heat, fuel leaks, jittering servos, loose control horns and the works. A general inspection is in order prior to flying again. If all is well go for it again.

Special notes for electric models: I like to spend 3 to 5 flights working my way up to a full power full aggression full length flight. If something is going to overheat and be damaged. Slowly working up my flight duration and aggressiveness gives me a chance to pinpoint any heat problems in the power system before damaging a major component. Maybe something needs more airflow or perhaps a propeller adjustment is in order.

Pay attention to how many mah your charger is putting back in the pack after each flight. This way you can get a good idea of your maximum safe flight time without ever hitting BEC cut off.

Take a minute to explain any improvements or adjustments you think the model needs. Perhaps if you have too much aileron trim in, you can look at taking a warp out of the wing if it exists or put in some sub trim so you can neutralize your radio trims.

It’s always a good idea if the owner makes these changes to put it up and reset it to good trims for them.

For my own models, I don’t really consider them ready to sport fly until I’ve put on a number of flights and gotten the throws just right. It’s always a good idea to look at any model as a work in progress for a while. Any model can be made to fly and handle better. Your worth the effort.

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