User Manual

JR XP9303 Sailplane Setup Addendum

By Joe Wurts

The write-up in the manual (by John Adams) on setting up a sailplane for the 9303 is a pretty

good one. I'm going to use that as a baseline, but note any differences. This write-up starts on

page 42.

My first difference is on step #8, Establishing Flight Modes.

I use four flight modes: Launch, Speed, Cruise, and Thermal. I also set up my radio so that the

Launch is on a two-position switch (On or Off), and the remaining three modes are on a three-

position switch. When the Launch mode is activated (On), it overrides whatever is selected on

the three-position mode switch. I assign the launch switch to the Elev D/R switch (ELE D/R), and

the three-position mode switch, denoted in the menu as SPEED, is assigned to the left three-

position switch (L3P), just to the right of the Elev D/R switch.

One other thing, I'm hardwired for having the switches be as physically representative as

possible, so when I want to pull down the trailing edge for launch, I want to pull the switch down.

The default is that the launch switch is activated when the switch is up. The way that I fixed mine

was to take off the back of the Tx and swap the two end wires going to the Elev D/R switch.

Leave the middle wire where it is, and swap the two outer wires, and you have reversed the

switch!

Minor note on Step #14

For clarity, the "crow" (aileron reflex with flap deflection) is governed by the SPOI FPRN 0 value.

I typically run about a 15% to 20% value here, just enough aileron reflex to preserve good roll

authority, along with no adverse yaw. If the plane has adverse yaw with full flaps, use a little bit

more reflex, and vice versa. I tend to want just a shade of proverse yaw to assist in last second

corrections for landing.

Also, note that the default SPOI offset of +170 results in no deadband in the flap stick. I am using

a value of +156 for the SPOI offset, so that when I am putting in rudder inputs, I don't accidentally

get a little flap deflection.

Step #16

Make sure that you have full-span camber for launch. I've had very few planes that launched

better with the ailerons deflected less than the flaps. Get the optimal TE setting and use it for the

whole wing, flaps and ailerons. Also, most people use too much reflex for speed. The most

needed (dependent on the airfoil) is typically about two degrees. A sanity check is to use a

straightedge on the lower surface. The ideal is that the straight- edge contacts at the trailing

edge, the hinge line, and another point in front of the hinge line. If the straightedge can rest on

the hinge line in the reflex position and rock back to touch the TE, or forward to touch the forward

part of the airfoil, there is too much reflex. For reference, my thermal ship has 14 degrees of

launch camber, -1.5 degree reflex for speed, and 3 degrees of camber for thermal mode.

Step #17

I do something unconventional here. For the thermal flight mode, I use a significant reduction in

the throw for both elevator and aileron. Also, it is the only time that I use exponential. Typical

values are about 50% for the D/R in thermal, along with about 30% of exponential. As will be

noted later, there are a few other things that I do in the thermal mode as well that are not typical.

Note: This is where you "orient" your 3-position flight mode switch. Scroll through the gain

values, until you get the AUTO to pop up (maybe insert a pretty picture here?). I set the Cruise

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JR XP9303 Sailplane Setup Addendum By Joe Wurts The write-up in the manual (by John Adams) on setting up a sailplane for the 9303 is a pretty good one. I'm going to use that as a baseline, but note any differences. This write-up starts on page 42. My first difference is on step #8, Establishing Flight Modes. I use four flight modes: Launch, Speed, Cruise, and Thermal.
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(CRUI) to Pos1, Speed (SPEE) to Pos0, which leaves Pos2 for Thermal. This should match the results from Step #8. Step #19 I put all switches at Pos 0, which makes the aileron>flap mix active all of the time. Again, not normal, but something that works for me. Step #20 One thing that should be typical for most fliers is in using a large amount of differential for launch. I typically use 75% to 90% aileron and flap differential for the launch mode.