3D flight is in a different speed regime than pattern flight, so it will necessarily have a few differences
in setup. These are:
Your CG can be slightly farther aft for a 3D only plane, and in almost every case this will make 3D maneuvers easier. It
sensitizes the rudder and elevator, making the plane react more quickly…at the cost of smooth straight and level flight.
Stop moving the CG aft when the plane gets hard to land. I would not go to the trouble of adding tail weight to my pattern
plane just for 3D flying. The amount of benefit of an aft CG is just not that great, so set the CG on a dual use plane to
optimize the pattern flying…the 3D flight will be fine. The one thing you do not want is an excessively nose heavy airplane.
A nose heavy plane will never fly decent 3D. The most common mistake here is putting a larger engine than your kit calls for.
The result is that you will either be too nose heavy, or have to add a ton of weight to the tail. Neither choice is desirable.
- Set your control throws to the maximum possible without binding (at least 45 degrees elevator and rudder - aileron is
not as critical)
- Use 60% to 70% exponential. Much more and the control will act like a switch…all on or all off…not good.
- The larger the diameter of your prop and lower the pitch, the more thrust you get. But, do not go so large that the throttle
sags. Throttle response is critical - and that comes from turning a smaller prop.
- Make sure your throttle curve is in a usable range. At a steady hover, you should be near the middle of stick travel.
If it is much off, adjust your curve to get the stick back to center in a hover.
- Never forget…wing loading is king when it comes to 3D. No extra weight!
In pattern we adjust our stick trims for high speed flight. In 3D we will readjust the trims for hovering flight, where
there is little or no free stream airflow over the model. Start with the elevator. Hover or torque roll your plane and see
if you find yourself holding elevator continuously in one direction. Adjust the trim until you are not holding the same elevator
direction all the time. If you are not yet able hold a hover, then just keep trying…note which way the plane falls out
each time and make small adjustments to correct. When set, you will find the plane no longer tracks straight and level with
hands off. That’s alright, because straight and level is a sin in 3D!
Rudder trim is a bit trickier. Fly level at 1/3 to ½ throttle and slam a few walls (rapidly pull the elevator all the way
straight back to the stop, so the plane pitches 90 degrees up). In all likelihood, the plane will snap off in one direction
or the other when you hit the wall. Note the direction. Fly several to make sure the plane reacts the same each time, and
make sure not to inadvertently add aileron when you pull back. Now add a unit of rudder trim opposite the direction the plane
snapped, and try it again. Remember to adjust your aileron trim every time you alter the rudder trim. When you are done, the
plane should slam a wall without snapping. How long it stays, is up to your flying abilities.
Your trims are now set for 3D.
Since you have changed your trim settings, your mixes will now be a little off. This is because we have altered the neutral
point from which they take affect. In addition, we are going to set the mixes way past the point we stopped in the pattern
discussions. Let’s get started…
As mentioned before, you should be using the multipoint or curve programmed mixes for 3D. The canned single point mixes
are normally inadequate. You will probably need to mix the rudder into the aileron and elevator. If you are running any throttle
mixes, just leave them alone…we aren’t worried about our vertical line drawing any more than we are about our
straight and level. That’s for sissies.
First, you need to see how many points of mix are available on your radio, and figure the space between each point. For
example, the Futaba 9C has 5 point mixes. There is one point in the center, and one each at both stick stops. That leaves
two points in each direction, so 50% throw between each point. The 9Z has 7 points of mix, with 3 on each side and one in
the middle, so it has 33% travel between points.
With that information, use the dual rate function of your radio to set your max rudder travel to the first mix point. On
the 9C that would be 50% total travel, on the 9Z - 33%. Now fly some knife edges with the rudder stick against the stop. Set
your elevator and aileron mixes as described in the basic setup section. Once satisfied at the first point, land and reset
your rudder rate to the next point…100% for the 9C, or 66% for the 9Z radio. Set that point, and keep moving to the
next until you are done.
If you are new to 3D, you are probably having a fit by now. In normal knife edge you are flying fast and control your flight
path using the rudder. We are going to change your technique…a lot! In 3D knife edge you hold the rudder against the
stop and use the power to control the flight path. More power and you climb, less and you descend. In all cases, you will
be flying knife edge considerably slower than you are used to, with the nose at a much higher angle. In all likelihood, the
plane will snap roll long before your rudder stick reaches the stop. Not to worry. Just note the direction the snap occurs…to
the gear or the canopy…to the left or the right? Land and adjust your elevator and aileron mixes a percent or two opposite
the direction of the snaps. Remember that the elevator is usually the cause of the snaps, more than the aileron.
When done, you should be able to hold high alpha knife edge with little or no input other than rudder.
There are some mixes available that can provide some benefit in 3D flight.
Ailevator. This allows you to mix your aileron inputs into your elevator halves.
It is a real help in maintaining roll control, even with no airflow over the wings.
Elevon. This allows you to move the ailerons with the elevator. It can be helpful
in tightening your waterfalls, or reduce the tendency to wing-rock while hovering. You can make the ailerons go up with
the elevator, or make them go down with the elevator. Each direction may have a desirable affect, depending on your
plane and the maneuver at hand. Experimentation is the name of the game. This is one mix that it is advisable
to have a switch to be able to turn it off.
Airbrake. On biplanes, you can program the ailerons on the top wing to deflect down, while
the bottom wing ailerons deflect up - and set the throttle position where it triggers. You are even offered an elevator
trim to compensate for any pitching affect. Talk about low speed down lines! Once again, turn it on with a switch
- or it could surprise you when you reduce the power for landing.
We need to talk a little more about your radio at this point. As you have probably noted, the majority of the difference
between 3D and pattern setup is in the software. Here is where the radio makes worlds of difference.
The JR 10X and Futaba 9Z or 14MX have flight modes and flight conditions. This nifty feature allows you to set your pattern
settings on one mode, and then flip a switch to another mode which is your 3D setup. Everything, even the stick trims can
be different between the modes! The beauty of these radios is that at the flip of a switch you completely change your plane’s
If you are working with a radio that does not have conditions or flight modes, you will have to be a bit more creative
to use the same plane to fly 3D and pattern. The easiest method is to copy your pattern settings to a second model in the
radio. Call this model 3D, and adjust the settings to optimize 3D as described above. You now have your 3D and pattern settings
ready to go. You will have to decide which you want before you fly, though.
If you are serious about flying pattern and 3D with the same plane, you should budget for one of these top line radios
early in your flying career. Their many additional features will make flying much easier.
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