A throttle mix will be used to adjust your vertical down-line so it tracks perfectly straight. Every plane I have ever
flown (that was not grossly tail-heavy) will tend to pitch towards the canopy when the power is off and you are flying straight
down. You must use a multi-point mix for this. If you do not have a multi-point mix available, you will normally be better
off just holding a little down elevator on your down lines, as a linear mix will mess up your level lines.
Your vertical up-line is normally adjusted by setting your engine thrust line, as described earlier. You do have the option
of using a mix from the throttle to the elevator, to accomplish the same thing.
Make a few level passes to adjust your elevator trim to neutral. Once satisfied, fly some nice long power off down-lines
to see if your plane pitches. If it does, land and set up your throttle mix.
Start by selecting a program-mix and setting the throttle as master and the elevator as slave. Activate the mix so it is
always on. If you are using dual channels for your elevators, also select the “link” function. Set all of the
points to zero, with the exception of the one at the idle position. Set the idle point to 50% rate to check for the correct
direction. If the plane pitched to the canopy in the test flight, then make sure the elevator deflects downward when the throttle
is brought to idle. Once the direction is correct, reduce the rate to 1% for starters. Retest and adjust a percent at a time
until the plane flies perfectly vertical down lines.
If you plan to use the up-line throttle mix, follow the steps described earlier for setting thrust-lines. Instead of setting
the thrust angle, set the above ½ throttle mix to accomplish the same thing. A single point mix here is preferred.
Note: Using throttle mixes does have some side effects, namely, the aircraft will pitch slightly whenever the throttle
is brought to idle. The only pattern maneuver this is annoying is when slowing for a spin. Learn to use slow/smooth throttle
motions and the mix will not be a problem. Overall, the benefits it gives on the down-lines overshadows the negative side
effects. Also, if you have a radio that has “flight modes” or “conditions”, do not set the throttle
mixes on your landing mode. You will not need them there. If you do not have flight modes and the mix bothers you for landing,
you can set it to deactivate with a switch. Personally, I don’t, simply because if a switch can be misplaced, I will
do it…and the minor pitching the mix causes isn’t that big of a deal.