The evolution of JR's computerized radios continues with the introduction of the new XP9303. This new radio adds some exciting features. The most interesting software upgrades are: 1. The multipoint programmable mixing has increased from 5 points to 7. The XP8103 added groundbreaking multipoint programmable mixing which completely eliminates that annoying bump the model takes when you first pull the flap stick down. Landing approaches become extremely smooth. The XP9303 increases the mix from 5 points to 7, making the approach even smoother. If you don't have this feature on your current radio, this feature alone is well worth the investment. If you've owned the JR347, the 388, or the XP8103, you will find some similarity in the programming, but the layout and location are quite a bit different. The switches are generally in the same place but the knobs have been replaced with digital trim switches. There are three versions of the XP9303: helicopter, airplane, and sailplane. The switches are in the same place, but you now only get one manual, where you used to get all three. Fortunately, all three manuals are available online at horizonhobby.com for you to download. In addition, there is a postage prepaid request form in the box for ordering the other two manuals from JR, free of charge. The XP9303 also sports a new and much larger screen. The new screen is nearly three times larger than that found on the XP8103 and has been moved from the top to the bottom of the radio. The screen is pixilated, allowing the computer to place a significant amount of information on the screen at one time. The larger screen also contains an X\Y axis graph that is designed to visually represent dual rates, exponential rates, and the multipoint programmable mixing. The new XP9303 supports a case significantly different than prior radios. The new radio still fits my hands better than any radio I have ever held. Some of the additional changes to the case include: 1. Only four buttons instead of eight. A new scroll wheel has been added to make scrolling through all the possible selections even easier. When you find the correct selection, just push to click the scroll wheel. The XP9303's transmitter modules are interchangeable with all other JR® radio modules. Flash memory is used for saving all the settings. No more internal battery to be replaced every few years or so. The sailplane version comes with three digital 386 servos (I have been using these servos for about a year and they are hot!) and the new slim line seven-channel receiver. The new R770 receiver is a high performance PCM single conversion receiver with the new 10KHz narrow band ABC&W circuitry. This new receiver is half the size and weight of the previous credit card style receiver. Digital trims were introduced with the 8103 and when you have a radio with multiple model memory, it is the only way to go. You no longer have to save your trim settings before you switch to a different model in the radio. As you switch from model to model, the radio automatically remembers the last trim setting of each model. If you fly two classes in your local competitions, you no longer have to swear at yourself for forgetting to save your last trim locations. No more sub-par launches when you forget to reset the trim lever to neutral before launching a different model. To change the trims, you simply bump the trim lever. Each time you bump the trim lever there is a corresponding change in the position of the control surface on the aircraft. A black dot moves along the graphic bar on the display screen and the radio makes a beep each time you bump the lever. If you bump the lever and hold it down, the trim will make rapid advancement in the direction the lever is held. As the trim is changed to the top or to the right, the beeps become come higher in pitch. As the trim is changed to the left or bottom, the beeps become lower in pitch. As the trim passes through the center position, a louder, more easily recognizable beep occurs. On the surface, digital trims do not sound like much of an improvement. Boy, what a surprise! The resolution of the digital trims is adjustable in the TRIM STEP mode. In its default mode, one click of the digital trim is approximately the same as the old style trims. The default can be changed so that it takes 3 or 4 clicks of the digital trim to equal one click with the old style trims. With the digital trim's finer resolution, the elevator "sweet spot" is much easier to find. Whether the resolution is fine or coarse, the total amount of trim adjustment remains the same (approximately 15 degrees each way from center). Over the last ten years or so, there has been a significant amount of discussion concerning elevator "dead band." "Dead band" may appear in several forms or any combination of forms. The most common is lack of pitch change with small stick changes near center. Another is a plane that cannot hunt. In other words, upon moving to level flight, the aircraft feels like it's mushing along (nose high). The next time the aircraft moves to level flight, it feels like it will not slow down (nose down). It seems to occur most often on aircraft with full flying stabs. There are many items that can contribute to "dead band." The ones most often discussed are sloppy linkages, poor choice of stabilizer airfoil cross-section, and worn out servo pots. Lack of trim resolution in the radio adds a new "dead band" contributor to the discussion. With a trim step resolution of only 1 or 2, dead band has all but disappeared. JR® has brought flexibility to a new level on the XP9303 by adding assignable switches, slides and sticks. For all you guys that have been demanding assignable switch locations, we hope you won't complain about the added complexity of radio programming. Flight Modes are the newest wrinkle in computer radios. Another manufacturer has a radio that allows an alternative setup that can be changed in flight. The XP9303 has five Flight Modes that can be changed in flight with the simple flip of a switch. Cruise is the default flight mode. The other flight modes are inhibited when the radio is first turned on. The XP9303 in this form has more power (side slides) than the XP8103, but not much. It is the power of the Flight Modes that make this radio really something. Each of the 5 flight modes (Launch, Cruise, Land, Speed and Thermal) can be easily selected in flight. Each Flight Mode allows you to program each of the following mixes separately: Dual Rate and Expo, Elevator-to-Flap, Aileron-to-Flap, Differential, FM Delay, Flaperon Mix, Aileron-to-Rudder mix, Butterfly, Flap Rate, and each of the non-dedicated mixes. In addition, you can set the radio so that each trim (Aileron, Elevator, Rudder, Flap and Flaperon) is the same for each Flight Mode or separate for each Flight Mode. As an example, elevator trim can be set so changing the trim in one flight mode will change it in all the remaining modes also. Alternatively, you can set the radio so that the trim settings for each flight mode have no effect on other flight modes. A practical application would be for different elevator trims in different flight modes. Start by flying and trimming the plane in COM (common) mode. In COM mode, elevator trim for all five flight modes has a common starting point. Once accomplished, switch to FM (Flight Mode) mode. You might want a couple click of up trim in launch and thermal mode, and a couple of clicks of down trim in speed and landing. Now, when you switch from Flight Mode to Flight Mode, the trims change automatically. Pretty cool. (In the following instruction sets, there is no reminder to switch to FM mode AFTER the initial trims have been established.) In addition, the radio can be set to transition slowly from one mode to another to reduce the suddenness of changing from one flight mode to another if there are significant trim differences. The trainer function instructions are now written right into the radio screen. The trainer function allows you to select the servos in the airplane that the trainee is controlling. In other words, you can selectively allow them to learn elevator first, then add rudder second, etc. One feature that you are not going to discover is an adjustable screen contrast. Although available on the XP8103, it is not present on the XP9303. The XP9303 allows you to transfer all the trim settings directly into another XP9303 through a trainer cord. You may not transfer trim settings from any radio other than another XP9303. Several mix values changed in the radio, making them incompatible for transfer through the trainer cord. A good description of how to make this function work can be found in the airplane manual. Over the years, there have been a lot of complaints about the lack of an "OFF" setting in computer radios. Most computer radios do not contain a setting called "OFF." Why? Because every function is "ON" all the time. As long as the mix value is set to -0-, nothing will happen. In other words, "OFF" and "-0-" are the same thing. The sailplane channel assignments with the 9303 have changed from prior radios. These new assignments are for all receivers (prior JR® and other brands). The new servo assignments are: Channel Assignments
JR claims this new channel assignment allows for better communication between the radio and the sailplane. What it really means is that a six-channel receiver will now work with a six-servo sailplane. All prior radios with JR setups would have required a seven-channel receiver. The motor assignment for a four-servo setup defaults to channel #5. When dual flaps are activated, the motor assignment defaults to channel #7 (AUX2). However, these defaults are easily changed. The battery may be plugged into any empty slot on the receiver or Y-harnessed if necessary. The new 770 receiver packaged with the radio is a seven-channel receiver with an eighth dedicated battery slot. Programming Review This article also assumes that you own an XP9303, have the manual handy and are familiar with the four programming buttons across the face of the radio and the selector wheel. The page numbers referenced in the article are the page numbers found in the manual. This manual provides the setup for several different types of sailplanes. The purpose is to show just how similar the programming is for each type of sailplane. You don't have to relearn the programming for a different model. The transmitter has two separate programming modes. These are the system setup mode and the function mode. The system setup mode comes at the beginning of the instruction manual (Page S2) and must be completed before you perform any of the function modes. (Page S15) If you program the function settings first, and then revise the system setup settings second, it may result in wiping out your programming and returning to the system defaults. Recommended Changes to the Manual
The following receiver channels can be assigned to any one of following switches, levers or sticks. This explains why the image of the radio seems to be missing some information:
Switch Assignments The following actions can be assigned to any one of the following switches, levers or sticks. Timer can be assigned to any of the following: Launch, Cruise, and Land Flight Mode can be assigned to any of the following switches. To put Launch, Cruise and Land on one switch would require a three-position switch. There are only two three-position switches and they are labeled R3P SW and L3P SW. (right and left three-position switch). If you choose to assign a flight mode to a two-position switch, the radio automatically selects the middle and upper positions and discards the lower position. As an example, if you choose the AIL D/R for your Launch, Cruise, Land Flight Mode, only Launch and Cruise are available as Flight Modes. The radio will automatically recognize this and whenever you come to a screen showing the available Flight Modes for mixing, Land will be missing. Speed, Thermal Flight Mode can be assigned to any of the following: The non-dedicated mixes can be turned on or off by selecting a flight mode or switch on the radio. Also, a non-dedicated mix can be activated by more than one switch or any combination of switches. This may look simple, but it can become complicated. AX4 and BTF are fixed switches. However, CRU, LAU, LAN, SPD, and THM are Flight Modes that can be assigned to any switch identified above. Non-dedicated mixes 3 through 6 are activated by the following switches: The following switches activate non-dedicated mixes 1 and 2: More Recommended Manual Changes Now that you have all the flexibility figured out, the following modifications to the manual are still recommended: 1. Page S2. On the diagram for [Device. SEL] insert the following under SPEED INH "TRIM:COM". TRIM:COM only appears on the screen when either or both of the flight modes are activated. COM (Common Mode) can be changed to FM (Flight Mode). This same change should be made on page S9, S11, S12, S13 and page S46. This allows trim to remain unchanged from Flight Mode to Flight Mode. Switching to FM means that each Flight Mode has its own trim settings. If trims are set to FM mode, be especially careful during the first flight to remember that the aircraft will need to be trimmed using the digital trims for Aileron, Elevator and Rudder for each Flight Mode selected during flight. If the aircraft is badly out of trim in one Flight Mode, it will probably be badly out of trim for each Flight Mode selected. Leave this condition set to COM for the first flight so trims are set for each Flight Mode. Only after trimming the aircraft, then go back into [Device. SEL] and change COM to FM. Now you can change trims for each Flight Mode with each Flight Mode starting from the same base line. By now, you are probably wondering what you have gotten yourself into. Don't worry, you're going to love it. |
| System Setup Mode You enter the system setup mode by pressing and holding down the ENT button on the face of the transmitter while turning the transmitter on. You will then see the screen entitled System M. (Page S2). Model SEL On the left-hand side of the display you will see Model SEL surrounded in dark. This dark area will be referred to throughout the article as the cursor. The cursor can be moved around the screen by scrolling the ROLLING SELECTOR. After you have selected the area you wish to enter, press the ROLLING SELECTOR until it clicks. 1. Start the programming by scrolling the cursor over Model SEL. (Page S3) Press the ROLLING SELECTOR. COPY Although not discussed in the manual, if you place the cursor over SELECT and press the ROLLING SELECTOR, COPY will appear. This allows you to copy a model from one of the 30 possible selections to another. If you select an already full location, the original programming will be lost. Once you get the from and to models selected, press the CLR button right next to where it says COPY on the screen. Pushing this button is what actually performs the copying. Exit. MDL Reset If you are setting up a plane in a template that has already been used, YOU MUST DELETE ALL THE PROGRAMMING IN THAT TEMPLATE FIRST. Scroll the cursor over MDL Reset and press the ROLLING SELECTOR. Press the CLR button. Exit. MDL Name Scroll the cursor over MDL Name and press the ROLLING SELECTOR. (Page S3) Scroll the ROLLING SELECTOR until an up-pointer appears under the < > brackets. Press the ROLLING SELECTOR. A screen appears with all the possible letters and characters. Scroll the cursor over the selected letter and press the ROLLING SELECTOR. Repeat until the name is filled in (limited to eight characters). Exit. Type SEL Scroll to Type SEL and press the ROLLING SELECTOR. Scroll to GLID and press the ROLLING SELECTOR. Exit (Page S4) MODULAT Scroll the cursor over MODULAT. and press the ROLLING SELECTOR (page S5). The cursor will be over Modulation. Press the ROLLING SELECTOR. Scroll the cursor over the type of receiver you have. The R770S receiver that comes with the radio is SPCM. Most of JR's older credit card receivers are SPCM. Some old JR ZPCM receivers will not work with this radio. Exit. TRIM STEP 1. Scroll the cursor over TRIM STEP and press the ROLLING SELECTOR. (Page S8) Wing TYPE Scroll the cursor over Wing TYPE and push the ROLLING SELECTOR. If you have a V-tail or DUAL FLAP scroll the cursor over INH and push the ROLLING SELECTOR to change it to ACT. If DUAL FLAP is INH, an ESC may be plugged into servo slot number 5 and the radio will default to the throttle stick working at this location. If DUAL FLAP is selected, an ESC may be plugged into servo slot number 7 and the radio will default to the throttle stick working at this location. Some RC Forum groups have alleged, "This means that no matter where you assign the MOTO function menu, the motor will be effected by the spoiler stick. For a 6-servo plane, this isn't workable." Fortunately, this belief is untrue. In the DeviceSEL menu, if AUX2 is inhibited, the spoiler stick no longer affects this channel and AUX2 may become a slave to any Mix. This option is discussed in more detail in the chapter on a 6-servo sailplane with a motor. Device SEL Scroll the cursor over DeviceSEL and push the ROLLING SELECTOR. This is the screen where magic happens. Below are setups for various types of sailplanes. For each of the sections identified below, go to the appropriate chapter. For each subsequent chapter, pick up with DeviceSEL and go from there. Types of Sailplanes Discussed in Detail in this Manual RUDDER, ELEVATOR AND SPOILER SETUP FOUR-SERVO AIRCRAFT FOUR-SERVO AIRCRAFT WITH FULL SPAN AILERONS FOR CAMBER CHANGE FOUR-SERVO AIRCRAFT WITH A MOTOR |
| RES (Rudder, Elevator, Spoiler) The goal here is to put the elevator and rudder on the right stick and put the spoiler on the left stick. You don't need to worry about switch locations, because you are not going to use any of them. If you have a Plug the elevator in to slot 3, the rudder into slot 4 and the spoiler into slot 5. This section assumes that you have read the beginning of the article concerning System Mode and have performed the setup described. The setup instructions below continue with DeviceSEL found in the System Mode. Return to System Mode 1. Scroll the cursor over DeviceSEL and push the ROLLING SELECTOR. After turning the radio on you will see the general information display. To enter the function mode, simply touch the LIST button. Servo Reversing Scroll the cursor over REV.SW and push the ROLLING SELECTOR. Slowly operate the rudder (left-hand stick), the elevator (right-hand stick) and the spoiler (identified on the REV.SW screen as MOT). Make sure that all of the control surfaces move in the correct direction. To reverse a servo, Scroll the cursor over the correct servo and push the ROLLING SELECTOR to change the servo from normal to reverse. Don't worry that the Rudder and Elevator are on different sticks. Later we will move the rudder to the right stick with a mixing function. Exit. Sub Trim Sub trim allows you to electronically center all of your control surfaces. Now that the servo direction is correct (the primary control surfaces all move in the right direction), it is time to align all of the control surfaces. All of the control surfaces must be aligned mechanically first. It's important to perform this function with the transmitter and receiver turned on and all trims set at neutral. Adjust the linkages and servo arms for the elevator and the rudder so that they are as close to neutral as possible. A computer radio will not make up for sloppy building. Scroll the cursor over Sub Trim and push the ROLLING SELECTOR. All of your sub trim values should read 0%. Scroll the cursor over the servo you need to align and push the ROLLING SELECTOR. Scroll the ROLLING SELECTOR left or right until the control surface is centered (elevator and rudder). You should not need to do this for the spoiler. Dual Rates Dual Rate functions are available for elevator and rudder. Now move the elevator stick in the other direction. As you can see, the dual rate function should have affected both the up and down elevator. (However, if your mechanical linkages are not symmetrical you still have more deflection in one direction than the other.) Perform the same function for rudder throw by fully deflecting the rudder stick (left stick) and adjusting the rudder dual rate appropriately. These instructions will only get you in the general area for the particular type, style and trim of your airplane. Use the dual rate function to modify the pitch (elevator) or roll (rudder) sensitivity of the aircraft to satisfy your personal taste. Once you have determined the optimum setting, you should program both switch positions for dual rate and exponential to be exactly the same. This prevents you from accidentally bumping a switch in flight and suddenly having an aircraft with different flying characteristics. Exit. Travel Adjustment Now that you have the two basic control surfaces (elevator and rudder) adjusted to the appropriate amount of control throw, it is now time for the final control throw adjustments. (The final adjustment of these control surfaces should be done at home on your workbench and not at the field.) The goal is to obtain equal travel adjustment for each of the servos. Unless you are an expert builder, or extremely lucky, the control surfaces will not move equally. As an example, the elevator will most likely move further in one direction than another. The fine-tuning of these control throws is now done using travel adjustment. 1. Scroll the cursor over TRVL ADJ. and push down the ROLLING SELECTOR. The same travel adjustments should be made to make sure that the rudder deflects the same both left and right. Move the spoiler stick to the top. Connect the spoiler linkage so the spoiler is closed. Slowly pull the spoiler stick down. Change the TRVL ADJ of the MOTO section so that you obtain full open spoiler at full down spoiler stick. Exit. Mixing Rudder on the Left Stick The goal for this type of airplane setup is to place ALL the directional controls on one stick. Elevator (up and down) and rudder (left and right) also on the right stick. 1. Scroll the cursor over Ail to Rud M and push the ROLLING SELECTOR. |
| FOUR-SERVO AIRCRAFT For a four-servo sailplane (two ailerons, elevator and rudder) The goal here is to put the aileron and elevator on the right stick and mix some rudder to the aileron stick also. Aircraft with roll controlled by ailerons may experience "adverse yaw." This occurs when there is insufficient differential in the ailerons. This adverse yaw is countered with rudder or differential in the ailerons. Some of that adverse yaw can be countered by mixing some aileron to the rudder. You don't need to worry about switch locations, because you are not going to use any of them. If you have a V-tail, perform the V-tail mixing found at the end of this article first. Plug the left aileron into slot 1, the right aileron into slot 2, the elevator in to slot 3, and the rudder into slot 4. This section assumes that you have read the beginning of the article concerning System Mode and have performed the setup described. The setup instructions below continue with DeviceSEL found in the System Mode. Return to System Mode 1. Scroll the cursor over DeviceSEL and push the ROLLING SELECTOR. After turning the radio on you will see the general information display. To enter the function mode simply touch the LIST button. Servo Reversing Slowly operate the rudder (left hand stick), the elevator (right hand stick) and the ailerons (right hand stick) Make sure that all of the control surfaces move in the correct direction. 1. Scroll the cursor over REV.SW and push the ROLLING SELECTOR. Sub Trim Sub trim allows you to electronically center all of your control surfaces. Now that the servos are all moving in the correct direction, it is time to align all of the control surfaces. All of the control surfaces must be aligned mechanically first. It's important to perform this function with the transmitter and receiver turned on. Adjust the linkages and servo arms for the ailerons, elevator and the rudder so that they are as close to neutral as possible. A computer radio will not make up for sloppy building. 1. Scroll the cursor over Sub Trim and push the ROLLING SELECTOR. All of your sub trim values should read 0%. Dual Rates Dual Rate functions are available for ailerons, elevator and rudder. 1. Scroll the cursor over D/R & EXP and push the ROLLING SELECTOR. Aileron Differential Aileron Differential is a critical component of trimming a sailplane with ailerons. If the ailerons travel the same amount both up and down, the aircraft is likely to develop "adverse yaw." In other words, when you roll the aircraft left (with aileron) the nose of the aircraft wants to go right. Lift creates drag so an aileron moving down creates more lift and more drag at the same time. An aileron moving up creates less lift and at the same time less drag. So, for a sailplane to roll to the left and have the nose of the aircraft go straight or left requires aileron differential. Less down than up. An aileron that goes up ¾ inch and only ¼ inch down has a 3 to 1 ratio. Slow flying, under cambered airfoils may require a ratio as high as 5 to 1. A faster flying, symmetrical airfoil may require a 1 to 1 ratio. To get the correct amount of aileron differential depends on the aircraft, the type of flying you line to do, pilot preference and how much rudder you use to coordinate your turn. 1. Scroll the cursor over DIFFEREN and push the ROLLING SELECTOR. Mixing Rudder to the Right Stick Another way to combat "adverse yaw" is to "coordinate" the turn with rudder input. You can still fly the rudder with your left stick. You can also use the Aileron to Rudder Mix so that the rudder is input with your right stick. 1. Scroll the cursor over Ail to Rud M. and push the ROLLING SELECTOR.
ADDITIONAL FOUR SERVO AIRCRAFT OPTIONS Camber Adjusting Full Span Ailerons Please read the section on adding camber to a six servo sailplane. The programming is the same even if DUAL FLAP is inhibited in the System Menu. You must still adjust FLAP RATE even if there are no flaps. You may have to experiment, but start with a FLAP RATE setting of around 50% DN. Make the same offset changes in Flaprn MX and input a percentage under FPRN DN until you get the amount of camber you want when the Left Side Slide is full down. Turning Full Span Ailerons into Spoilers or Flaps Please read the section on adding landing flaps to a six servo sailplane. You use the same Butterfly programming. Instead of mixing SPOI to FLAP, you simply mix SPOI to FPRN instead. Adding a Motor Please read the section on adding a motor to a six servo sailplane. If you have a 7 channel receiver all the programming will work here also. If SPOI ST is selected in the DeviceSEL/MOTO menu, even the MOTO HOLD function is available. If you only have a six channel receiver, simply mix MOTO to any available channel (5 or 6). The Right Side Slider is only available as a direct mix to channel 7 in the DeviceSEL menu under AUX2. If you want to put the motor on the Right Side Slider, you will have to mix AUX2 to Channel 5 (gear) or Channel 6 (AUX1). |
| SIX SERVO AIRCRAFT SIMPLE SETUP. ONLY ONE SWITCH AT THE TOP OF LAUNCH The goal here is to: 1. Put the aileron and elevator on the right stick and mix some rudder to the aileron stick. Before you begin, make sure the servos in the wings are inserted so that the arm side of the servo faces the wing tip and closest to the leading edge of the wing. I further recommend, that during normal flight mode, you set up your radio so that all of the switches are in the same direction. I prefer starting at the top, back of the radio and pulling my hand forward and down and move all the switches in that direction. This further simplifies flying and allows you to quickly check your radio without looking down at it by simply passing your hands over all the switches. Plug the left aileron in to slot 1, the right aileron into slot 2, the elevator in to slot 3, the rudder into slot 4, right flap into slot 5 and left flap into slot 6. This section assumes that you have read the beginning of the article concerning System Mode and have performed the setup described. The setup instructions below continue with DeviceSEL found in the System Mode. Return to System Mode 1. You enter the system setup mode by pressing and holding down the ENT button on the face of the transmitter while turning the transmitter on. You will then be confronted with the screen entitled [System M]. (Page S2). Function Mode After turning the radio on you will see the general information display. To enter the function mode simply touch the LIST button. If you have a V-tail, perform the V-tail mixing found at the end of this article first. Servo Reversing Slowly operate the rudder (left hand stick), the elevator (right hand stick) and the ailerons (right hand stick) Make sure that all of the control surfaces move in the correct direction. 1. Scroll the cursor over REV.SW and push the ROLLING SELECTOR. Sub Trim Sub trim allows you to electronically center all of your control surfaces. Now that the servos are all moving in the correct direction, it is time to align all of the control surfaces. All of the control surfaces must be aligned mechanically first. It's important to perform this function with the transmitter and receiver turned on and all trims set to neutral. Adjust the linkages and servo arms for the ailerons, elevator and the rudder so that they are as close to neutral as possible. A computer radio will not make up for sloppy building. 1. Scroll the cursor over Sub Trim and push the ROLLING SELECTOR. All of your sub trim values should read 0%. Dual Rates Dual Rate functions are available for ailerons, elevator and rudder. 1. Scroll the cursor over D/R & EXP and push the ROLLING SELECTOR. These instructions will only get you in the general area for the particular type, style and trim of your airplane. Use the dual rate function to modify the pitch or roll sensitivity of the aircraft to satisfy your personal taste. I highly recommend, that once you have determined the optimum setting, that you program both switch positions (Pos-0 and Pos-1) for dual rate and exponential to be exactly the same. This alleviates you from accidentally bumping a switch in flight and suddenly having an aircraft with different flying characteristics. Exponential rates are another way to adjust sensitivity of the sticks on your radio. The servos are a rotary output device. Although the line on the EXP screen may start out as what appears to be a linear output, it is rather misleading. Because the servos are a rotary output device, there is a built in negative exponential rate in you servos to begin with. In other words, the stick is naturally more sensitive near the center than it is at the extremes. A servo that uses full servo arm deflection each way from center has a negative exponential of a little more than 30 percent. Obviously, if the D/R is reduced so that the servo arm deflection is less than full deflection, the amount of negative EXP is reduced. If this is your first chance to EXP, you might want to try a EXP rate of around positive 20 to 25 percent. This will give you a more linear output at the servo. This is a personal choice issue. There is no right or wrong amount of EXP. Exit. Travel Adjustment Now that you have four basic control surfaces (aileron, elevator and rudder) adjusted to appropriate amount of control throw, it is now time for the final adjustments. (The final adjustment of these control surfaces should be done at home on your work bench and not in the field.) The goal is to obtain travel adjustment as close to 100% as possible for the four servos. Unless you are an expert builder or awful darn lucky the control surfaces will not move equally. As an example, the elevator will move further up than it does down. The fine tuning of these control throws is now done using travel adjustment. 1. Scroll the cursor over TRVL ADJ. and push down the ROLLING SELECTOR. Aileron Differential Aileron Differential is a critical component of trimming a sailplane with ailerons. If the ailerons travel the same amount both up and down, the aircraft is likely to develop "adverse yaw." In other words, when you roll the aircraft left (with aileron) the nose of the aircraft wants to go right. Lift creates drag so an aileron moving down creates more lift and more drag at the same time. An aileron moving up creates less lift and at the same time less drag. So, for a sailplane to roll to the left and have the nose of the aircraft go straight or left requires aileron differential. Less down than up. An aileron that goes up ¾ inch and only ¼ inch down has a 3 to 1 ratio. Slow flying, under cambered airfoils may require a ratio as high as 5 to 1. A faster flying, symmetrical airfoil may require a 1 to 1 ratio. To get the correct amount of aileron differential depends on the aircraft, the type of flying you line to do, pilot preference and how much rudder you use to coordinate your turn. 1. Scroll the cursor over DIFFEREN and push the ROLLING SELECTOR. Mixing the Rudder to the Right Stick Another way to combat "adverse yaw" is to "coordinate" the turn with rudder input. You can fly the rudder with your right stick. You can also use the Aileron to Rudder Mix so that the rudder is input with your right stick. 1. Scroll the cursor over Ail to Rud M. and push the ROLLING SELECTOR. You now have control sufficient for the flying of the aircraft. You just don't have any landing or lift control devises yet. Flaps and Landing Mode Now that the basic control surfaces of the aircraft have been completed, the remainder of this section will focus on various flight modes which involve the use of flaps. These will include launch, cruise and land Flight Modes as will as full span camber changing. Flaps and Their Connection View page S48 of the manual. The setting of the servo arm and the correct Sub Trim is critical to the operation of the flaps. Because the flap move through as much a 90 degrees, the Sub Trim of the flap servos requires a large offset. 1. Remove the Flap control rods from either the servo arm or the flap horn. Flap Control on the Left Stick 1. Scroll the cursor over Butterfly and push the ROLLING SELECTOR. The XP9303 also provides for a specialized mix function which will completely eliminate that annoying bump that the airplane makes when you first pull the flaps down. That specialized mixing function is discussed later under Multi-Point Programmable Mixing. Launch Flap Preset This is the first time you will use flight modes. Earlier we activated the Launch, Cruise, Land mode and placed it on the L3P SW. There are three flight modes on this switch. Although they are labeled Launch, Cruise and Land, you can actually use them for anything you want. 1. Move the L3P SW to the launch position. (up on the radio.) Full Span Camber Adjustment Full span camber changing allows you to change the shape of the wing during flight. This function allows you to change the entire trailing edge of the wing. There is quite a current discussion concerning trailing edge camber and how it should be employed. Some argue that camber should be adjustable, from none to as much a ¼ inch. Others argue that there is only one setting for each airfoil that provides the greatest lift and that camber should just be on a switch. Simply on or off. This section will show you how to put camber changing on the left side slide. 1. Scroll the cursor over FLAP RATE and push the ROLLING SELECTOR. So far we have flaps moving down from the center position of the Left Side Slide. Now we have to make a decision. That decision is about reflex. Reflex is lowering the drag of the wing by raising the trailing edge. It does not take much. Put a straight edge across the bottom the wing. The straight edge should contact the bottom of the wing at the thickest portion and at the trailing edge. Start raising the trailing edge. As soon as the straight edge touches the wing in three locations, (at the hinge line) you have all the reflex you need. Reflex is for going fast. The question is, do you want to deploy reflex or not? Recall, the goal of this version of the programming is to perform the entire flight mode and only flip one switch, at the top of the zoom. The only real option with this programming restriction is to use the upper half of the side slide for Reflex. In a later programming version, with more than one switch to be thrown in flight, we put reflex on a switch. You can do one or the other, YOU CANNOT DO BOTH. Only Camber Adjustment on the Left Side Slide 1. Scroll the cursor over FLAP RATE and push the ROLLING SELECTOR. Reflex on the Side Slide Using the Upper Half of the Side Slide Movement 1. Scroll the cursor over FLAP RATE and push the ROLLING SELECTOR. So here are the things you do in a flight with this programming 1. If you have reflex on the Left Side Slide, move the slide all the way to the top. Multi-Point Programmable Mixing Traditionally, mixing functions in computer radios only allow a linear mix between the master and the slave channels. As an example, when the aileron to rudder mix is activated, and you push the aileron stick all the way to the stop, it mixes in a pre-programmed amount of rudder deflection. With multi-point programmable mixing, the XP9303 radio allows you to insert up to seven different mix points anywhere on the curve. In other words, as you slowly push the aileron stick all the way to the stop, you could literally make the rudder waggle back and forth. In the case of model sailplanes, this allows you to mix a larger percentage of elevator compensation during the initial part of flap movement and less elevator compensation as flaps approach 90°. This completely eliminates that bump your airplane takes on approach as you pull the flap stick down. The XP9303 radio provides six extra programming functions that allow you to assign any slave to any master channel. The first of these additional mix functions allow the multi-point programmable mixing and is defaulted to mix Flap to Elevator. The remaining four provide the ability to do things like add additional aileron/rudder mix during launch, and automatically eliminate the aileron/rudder mix in reflex mode. To eliminate that annoying bump on approach when you pull down the flap stick, there is a very deliberate sequence of steps that you should follow. First, program the radio as indicated above for flap and elevator compensation on approach. Launch the airplane and adjust the elevator compensation until you achieve the proper glide path at full flap. Ignore the bump for now. Some individuals want the airplane, at full flap to continue on the same flight path before the flaps were lowered. Other individuals like the airplane to take a decidedly strong downward pitch when the flaps are lowered. This insures that you don't lose flying speed and stall your airplane. However, there is no situation where after pulling the flaps all the way down, the plane should pitch upward. This situation is unacceptable and should be avoided. The steps below will be used to determine the amount of Elevator compensation at full flap using the Butterfly Mix. At mid Flap stick, the sailplane will want to float up. Full Elevator compensation at full flap needs to be determined and marked on the fin/Rudder. Once the fin is marked, the elevator compensation in the Butterfly mode is reduced to zero and PROG. Mix1 will be used instead. 1. Scroll the curser over Butterfly in the program mode and push the ROLLING SELECTOR. After all of that work, you have now accomplished exactly what the elevator compensation section in the butterfly mixing was able to perform with a single button. Now, let the magic begin. Launch your aircraft and verify, at least three or four mistakes high, that the elevator compensation is correct at full flap. If it is not, land and adjust Point-0 until you have achieved the proper amount of elevator compensation with full flaps. Launch the aircraft again. Three or four mistakes high pull the flap stick down to mid flap and add or subtract Elevator Compensation until the flight path at mid Flap stick (Point-3) is also neutral. It takes a while to get this right. You are not going to get it on your first try. You may have to increase or decrease the mixing at POINT-3 until it is perfect. You may also need to adjust Point-5 and Point-4. Variations in the size of flaps and effectiveness of different elevators will require experimentation. Two meter aircraft respond well to a single but strong bump on the curve at POINT-4 and 5. Unlimited aircraft respond to a more gentle curve by adding additional compensation at POINT-2 and 1. When it is perfect, its sweet. Worth the price of admission. I recommend having a buddy pull the flap stick down while you are flying. By setting up the radio so that it is in PROG.Mix1 before launch, your buddy can pull the stick down until the vertical line on the graph is right above point 1 through 5. Because the mixing only works on one of these points, your adjustments upon landing will be MUCH more appropriate and you will nail this portion of the programming just that much quicker. Increasing Aileron to Rudder Mix During Launch I trim my models to fly with little aileron/rudder mixing during normal flight modes. However, this means at launch, I have little if any rudder to recover from a bad throw. (Recall aileron controls roll, making it virtually worthless in this situation. Rudder controls yaw, like a rudder in the back of a boat, and is MUCH more important on launch) It's easy to increase the aileron/rudder mix during launch with the Launch Mode Switch. 1. Scroll the cursor over Ail to Rud M. and push the ROLLING SELECTOR. |
| SIX SERVO AIRCRAFT WITH FULL TRAILING EDGE CAMBER, REFLEX ON A SWITCH WITH ALL FIVE FLIGHT MODES TURNED ON The goal here is to: 1. Put the aileron and elevator on the right stick and mix some rudder to the aileron stick. Before you begin, make sure the servos in the wings are inserted so that the arm side of the servo faces the wing tip and is closest to the leading edge of the wing. I further recommend, that during normal flight mode, you set up your radio so that most of the switches are in the same direction. I prefer starting at the top back of the radio and pulling my hand forward and down and move all the switches in that direction. This further simplifies flying and allows you to quickly check your radio without looking down at it by simply passing your hands over all the switches. Plug the left aileron in to slot 1, the right aileron into slot 2, the elevator in to slot 3, and the rudder into slot 4, right flap into slot 5 and left flap into slot 6. This section assumes that you have read the beginning of the article concerning System Mode and have performed the setup described. The setup instructions below continue with DeviceSEL found in the System Mode. Return to System Mode 1. You enter the system setup mode by pressing and holding down the ENT button on the face of the transmitter while turning the transmitter on. You will then be confronted with the screen entitled System M. (Page S2). The Flight Mode Switches have a series of default positions. If Launch or Land are selected, either will override Speed or Thermal. For Speed or Thermal to work, the Left Three Position Switch must be in the middle position. (Cruise) Return to Function Mode After turning the radio on you will see the general information display. To enter the function mode simply touch the LIST button. If you have a V-tail, perform the V-tail mixing found at the end of this article first. Servo Reversing Slowly operate the rudder (left hand stick), the elevator (right hand stick) and the ailerons (right hand stick) Make sure that all of the control surfaces move in the correct direction. 1. Scroll the cursor over REV.SW and push the ROLLING SELECTOR. Sub Trim Sub trim allows you to electronically center all of your control surfaces. Now that the servos are all moving in the correct direction, it is time to align all of the control surfaces. All of the control surfaces must be aligned mechanically first. It's important to perform this function with the transmitter and receiver turned on. Adjust the linkages and servo arms for the ailerons, elevator and the rudder so that they are as close to neutral as possible. A computer radio will not make up for sloppy building. 1. Scroll the cursor over Sub Trim and push the ROLLING SELECTOR. All of your sub trim values should read 0%. Dual Rates You are about to experience the power of flight modes. Dual Rate functions are available for ailerons, elevator and rudder. The first portion of this section is to obtain a D/R setting that is close to the rates specified for the particular aircraft. The second portion will then discuss how to assign particular D/R to a particular flight mode. 1. Scroll the cursor over D/R & EXP and push the ROLLING SELECTOR. Travel Adjustment Now that you have four basic control surfaces (aileron, elevator and rudder) adjusted to appropriate amount of control throw, it is now time for the final adjustments. (The final adjustment of these control surfaces should be done at home on your work bench and not in the field.) The goal is to obtain travel adjustment as close to 100% as possible for the four servos. Unless you are an expert builder or awful darn lucky the control surfaces will not move equally. As an example, the elevator will move further up than it does down. The fine tuning of these control throws is now done using travel adjustment. 1. Scroll the cursor over TRVL ADJ. and push down the ROLLING SELECTOR. Back to Dual Rates The power of flight modes is here! 1. Scroll the cursor over D/R & EXP and push the ROLLING SELECTOR. It is up to you and your airplane to determine how best to use Dual Rates. Some other areas where it might come in useful: 1. Rudder: Launch - more, Land - more, Speed - less Exponential rates are another way to adjust sensitivity of the sticks on your radio. The servos are a rotary output device. Although the line on the EXP screen may start out as what appears to be a linear output, it is rather misleading. Because the servos are a rotary output device, there is a built in negative exponential rate in you servos to begin with. In other words, the stick is naturally more sensitive near the center than it is at the extremes. A servo that uses full servo arm deflection each way from center has a negative exponential of a little more than 30 percent. Obviously, if the D/R is reduced so that the servo arm deflection is less than full deflection, the amount of negative EXP is reduced. If this is your first chance to EXP, you might want to try a EXP rate of around positive 20 to 25 percent. This will give you a more linear output at the servo. This is a personal choice issue. There is no right or wrong amount of EXP. Exit. Aileron Differential Aileron Differential is a critical component of trimming a sailplane with ailerons. If the ailerons travel the same amount both up and down, the aircraft is likely to develop "adverse yaw." In other words, when you roll the aircraft left (with aileron) the nose of the aircraft wants to go right. Lift creates drag so an aileron moving down creates more lift and more drag at the same time. An aileron moving up creates less lift and at the same time less drag. So, for a sailplane to roll to the left and have the nose of the aircraft go the same way requires aileron differential. Less down than up. An aileron that goes up ¾ inch and only ¼ inch down has a 3 to 1 ratio. Slow flying, under cambered airfoils may require a ratio as high as 6 to 1. A faster flying, symmetrical airfoil may require a 1 to 1 ratio. To get the correct amount of aileron differential depends on the aircraft, the type of flying you like to do, pilot preference and how much rudder you use to coordinate your turn. 1. Scroll the cursor over DIFFEREN and push the ROLLING SELECTOR. Mixing the Rudder to the Right Stick Another way to combat "adverse yaw" is to "coordinate" the turn with rudder input. You can fly the rudder with your right stick. You can also use the Aileron to Rudder Mix so that the rudder is input with your right stick. 1. Scroll the cursor over Ail to Rud M. and push the ROLLING SELECTOR. Now go back and mix Aileron to Rudder in the other Flight Modes you have activated. In general, Launch, Land and Thermal may require more mix. Speed usually takes less. Aileron to Rudder Mix is a personal thing and depends on your ability to fly the Rudder Stick on the radio. So far, you have programmed the radio so that you can make the sailplane pitch up or down, yaw let or right and roll like a cork screw. Cool, but can you land on a dime? Landing Flaps and Landing Mode Now that the basic control surfaces of the aircraft have been completed, the remainder of this section will focus on various flight modes which involve the use of flaps. These will include launch, cruise and land Flight Modes as will as full span camber changing. Landing Flaps and Their Connection View page S48 of the manual. The setting of the servo arm and the correct Sub Trim is critical to the operation of the flaps. Because the flaps move through as much a 90 degrees, the Sub Trim of the flap servos requires a large offset. 1. Remove the Flap control rods from either the servo arm or the flap horn. Landing Flaps on the Left Stick 1. Scroll the cursor over Butterfly and push the ROLLING SELECTOR. The XP9303 also provides for a specialized mix function which will completely eliminate that annoying bump that the airplane makes when you first pull the flaps down. That specialized mixing function is discussed later under Multi-Point Programmable Mixing. Launch Flap Preset Flight Modes, here we go again. Earlier we activated the Launch, Cruise, Land mode and placed it on the L3P SW. There are three flight modes on this switch. Although they are labeled Launch, Cruise and Land, you can actually use them for anything you want. 1. Move the L3P SW to the launch position. (up on the radio.) Full Span Camber Adjustment Full span camber changing allows you to change the shape of the wing during flight. This function allows you to change the entire trailing edge of the wing. There is quite a current discussion concerning trailing edge camber and how it should be employed. Some argue that camber should be adjustable, from none to as much a ¼ inch. Others argue that there is only one setting for each airfoil that provides the greatest lift and that camber should just be on a switch. Simply on or off. This section will show you how to put camber changing on the left side slide. 1. Scroll the cursor over FLAP RATE and push the ROLLING SELECTOR. This section will mix the Ailerons to the Flap on the Left Side Slide and use the entire side slide (top to bottom) for Camber changing. 1. Move the Left Side Slide all the way to the top. Reflex Reflex is Latin for "go fast, go very fast." And there is a way to help you sailplane move across the sky. Reflex is lowering the drag of the wing by raising the trailing edge. It does not take much. Put a straight edge across the bottom the wing. The straight edge should contact the bottom of the wing at the thickest portion and at the trailing edge. Start raising the trailing edge. As soon as the straight edge touches the wing in three locations, (at the hinge line) you have all the reflex you need. Reflex is for going fast. 1. Place the L3P SW in Cruise Mode (Middle position). Multi-Point Programmable Mixing Traditionally, mixing functions in computer radios only allow a linear mix between the master and the slave channels. As an example, when the aileron to rudder mix is activated, and you push the aileron stick all the way to the stop, it mixes in a pre-programmed amount of rudder deflection. With multi-point programmable mixing, the XP8103 radio allows you to insert up to seven different mix points anywhere on the curve. In other words, as you slowly push the aileron stick all the way to the stop, you could literally make the rudder waggle back and forth. In the case of model sailplanes, this allows you to mix a larger percentage of elevator compensation during the initial part of flap movement and less elevator compensation as flaps approach 90°. This completely eliminates that bump your airplane takes on approach as you pull the flap stick down. The XP9303 radio provides six extra programming functions that allow you to assign any slave to any master channel. The first of these additional mix functions allow the multi-point programmable mixing and is defaulted to mix Flap to Elevator. The remaining four provide the ability to do things like add additional aileron/rudder mix during launch, and automatically eliminate the aileron/rudder mix in reflex mode. To eliminate that annoying bump on approach when you pull down the flap stick, there is a very deliberate sequence of steps that you should follow. First, program the radio as indicated above for flap and elevator compensation on approach. Launch the airplane and adjust the elevator compensation until you achieve the proper glide path at full flap. Ignore the bump for now. Some individuals want the airplane, at full flap to continue on the same flight path before the flaps were lowered. Other individuals like the airplane to take a decidedly strong downward pitch when the flaps are lowered. This insures that you don't lose flying speed and stall your airplane. However, there is no situation where after pulling the flaps all the way down, the plane should pitch upward. This situation is unacceptable and should be avoided. The steps below will be used to determine the amount of Elevator compensation at full flap using the Butterfly Mix. At mid Flap stick, the sailplane will want to float up. Full Elevator compensation at full flap needs to be determined and marked on the fin/Rudder. Once the fin is marked, the elevator compensation in the Butterfly mode is reduced to zero and PROG. Mix1 will be used instead. 1. Scroll the curser over Butterfly in the program mode and push the ROLLING SELECTOR. Launch your aircraft and verify, at least three or four mistakes high, that the elevator compensation is correct at full flap. If it is not, land and adjust Point-0 until you have achieved the proper amount of elevator compensation with full flaps. Launch the aircraft again. Three or four mistakes high pull the flap stick down to mid flap and add or subtract Elevator Compensation until the flight path at mid Flap stick (Point-3) is also neutral. It takes a while to get this right. You are not going to get it on your first try. You may have to increase or decrease the mixing at POINT-3 until it is perfect. You may also need to adjust Point-5 and Point-4. Variations in the size of flaps and effectiveness of different elevators will require experimentation. Two meter aircraft respond well to a single but strong bump on the curve at POINT-4 and 5. Unlimited aircraft respond to a more gentle curve by adding additional compensation at POINT-2 and 1. When it is perfect, its sweet. Worth the price of admission. I recommend having a buddy pull the flap stick down while you are flying. By setting up the radio so that it is in PROG.Mix1 before launch, your buddy can pull the stick down until the vertical line on the graph is right above point 1 through 5. Because the mixing only works on one of these points, your adjustments upon landing will be MUCH more appropriate and you will nail this portion of the programming just that much quicker. Increasing Aileron to Rudder Mix During Different Flight Modes I trim my models to fly with little aileron/rudder mixing during normal flight modes. However, this means at launch, I have little if any rudder to recover from a bad throw. (Recall aileron controls roll, making it virtually worthless in this situation. Rudder controls yaw, like a rudder in the back of a boat, and is MUCH more important on launch) Its easy to increase the aileron/rudder mix during launch with the Launch Mode Switch. On the other hand, Aileron to Rudder Mix may need to be reduced in the Speed Mode. 1. Scroll the cursor over Ail to Rud M. and push the ROLLING SELECTOR. How to Use This Programming 1. Flip the R3P SW to SPEED. (switch up) Other Things You Might Want to Try With This Programming In Cruise Mode: In Launch Mode: In Speed Mode: In Thermal Mode: In Landing Mode: |
| SIX SERVO AIRCRAFT WITH FULL TRAILING EDGE CAMBER, TURNING ON THE LAUNCH, CRUISE, CAMBER FLIGHT MODE AND A MOTOR We have reached the difficult one. So far, the Throttle Stick is used for landing flaps. The Left Slider is used for trailing edge camber. Where do we put the throttle control for the electric motor? Well, if you have soft start on you speed control, it can use any one of many switches. If you don't, you need something that is adjustable. You are limited to the throttle stick or the right side slider. The throttle stick is a problem. Motor control is usually off at the bottom and full power at the top. Flap control is usually up flap at the top and 90 degree flap at the bottom. The use of the throttle stick for both throttle and flap control is possible, but requires a switch to be flipped and the stick has to be in the correct place. As an example, you are on approach, half flap, and you decide to go around. If you raise the flaps first and when you switch the stick from flap to motor, the motor will instantly go to full throttle. Flight modes again come to the rescue. The goal here is to: 1. Put the aileron and elevator on the right stick and mix some rudder to the aileron stick to help adverse yaw. Before you begin, make sure the servos in the wings are inserted so that the arm side of the servo faces the wing tip and is closest to the leading edge of the wing. I further recommend, that during normal flight mode, you set up your radio so that most of the switches are in the same direction. I prefer starting at the top back of the radio and pulling my hand forward and down and move all the switches in that direction. This further simplifies flying and allows you to quickly check your radio without looking down at it by simply passing your hands over all the switches. Plug the left aileron in to slot 1, the right aileron into slot 2, the elevator in to slot 3, and the rudder into slot 4, right flap into slot 5 and left flap into slot 6 and the ESC for the motor into slot 7. This section assumes that you have read the beginning of the article concerning System Mode and have performed the setup described. The setup instructions below continue with DeviceSEL found in the System Mode. Return to System Mode 1. You enter the system setup mode by pressing and holding down the ENT button on the face of the transmitter while turning the transmitter on. You will then be confronted with the screen entitled System M. (Page S2). The Flight Mode Switches have a series of default positions. If Launch or Land are selected, either will override Speed or Thermal. For Speed or Thermal to work, the Left Three Position Switch must be in the middle position. (Cruise) Return to Function Mode After turning the radio on you will see the general information display. To enter the function mode simply touch the LIST button. If you have a V-tail, perform the V-tail mixing found at the end of this article first. Servo Reversing Slowly operate the rudder (left hand stick), the elevator (right hand stick) and the ailerons (right hand stick) Make sure that all of the control surfaces move in the correct direction. 1. Scroll the cursor over REV.SW and push the ROLLING SELECTOR. Sub Trim Sub trim allows you to electronically center all of your control surfaces. Now that the servos are all moving in the correct direction, it is time to align all of the control surfaces. All of the control surfaces must be aligned mechanically first. It's important to perform this function with the transmitter and receiver turned on. Adjust the linkages and servo arms for the ailerons, elevator and the rudder so that they are as close to neutral as possible. A computer radio will not make up for sloppy building. 1. Scroll the cursor over Sub Trim and push the ROLLING SELECTOR. All of your sub trim values should read 0%. Dual Rates You are about to experience the power of flight modes. Dual Rate functions are available for ailerons, elevator and rudder. The first portion of this section is to obtain a D/R setting that is close to the rates specified for the particular aircraft. The second portion will then discuss how to assign particular D/R to a particular flight mode. 1. Scroll the cursor over D/R & EXP and push the ROLLING SELECTOR. Travel Adjustment Now that you have four basic control surfaces (aileron, elevator and rudder) adjusted to appropriate amount of control throw, it is now time for the final adjustments. (The final adjustment of these control surfaces should be done at home on your work bench and not in the field.) The goal is to obtain travel each way from center that is as equal as possible. Unless you are an expert builder or awful darn lucky the control surfaces will not move equally. As an example, the elevator will move further up than it does down. The fine tuning of these control throws is now done using travel adjustment. 1. Scroll the cursor over TRVL ADJ. and push down the ROLLING SELECTOR. Back to Dual Rates The power of flight modes is here! 1. Scroll the cursor over D/R & EXP and push the ROLLING SELECTOR. It is up to you and your airplane to determine how best to use Dual Rates. Some other areas where it might come in useful: 1. Rudder: Launch - more, Land - more, Speed - less Exponential rates are another way to adjust sensitivity of the sticks on your radio. The servos are a rotary output device. Although the line on the EXP screen may start out as what appears to be a linear output, it is rather misleading. Because the servos are a rotary output device, there is a built in negative exponential rate in you servos to begin with. In other words, the stick is naturally more sensitive near the center than it is at the extremes. A servo that uses full servo arm deflection each way from center has a negative exponential of a little more than 30 percent. Obviously, if the D/R is reduced so that the servo arm deflection is less than full deflection, the amount of negative EXP is reduced. If this is your first chance to EXP, you might want to try a EXP rate of around positive 20 to 25 percent. This will give you a more linear output at the servo. This is a personal choice issue. There is no right or wrong amount of EXP. Exit. Aileron Differential Aileron Differential is a critical component of trimming a sailplane with ailerons. If the ailerons travel the same amount both up and down, the aircraft is likely to develop "adverse yaw." In other words, when you roll the aircraft left (with aileron) the nose of the aircraft wants to go right. Lift creates drag so an aileron moving down creates more lift and more drag at the same time. An aileron moving up creates less lift and at the same time less drag. So, for a sailplane to roll to the left and have the nose of the aircraft go the same way requires aileron differential. Less down than up. An aileron that goes up ¾ inch and only ¼ inch down has a 3 to 1 ratio. Slow flying, under cambered airfoils may require a ratio as high as 6 to 1. A faster flying, symmetrical airfoil may require a 1 to 1 ratio. To get the correct amount of aileron differential depends on the aircraft, the type of flying you like to do, pilot preference and how much rudder you use to coordinate your turn. 1. Scroll the cursor over DIFFEREN and push the ROLLING SELECTOR. Mixing the Rudder to the Right Stick Another way to combat "adverse yaw" is to "coordinate" the turn with rudder input. You can fly the rudder with your right stick. You can also use the Aileron to Rudder Mix so that the rudder is input with your right stick. 1. Scroll the cursor over Ail to Rud M. and push the ROLLING SELECTOR. Now go back and mix Aileron to Rudder in the other Flight Modes you have activated. In general, Launch, Land and Thermal may require more mix. Speed usually takes less. Aileron to Rudder Mix is a personal thing and depends on your ability to fly the Rudder Stick on the radio. So far, you have programmed the radio so that you can make the sailplane pitch up or down, yaw let or right and roll like a cork screw. Cool, but can you land on a dime? Landing Flaps and Landing Mode Now that the basic control surfaces of the aircraft have been completed, the remainder of this section will focus on various flight modes which involve the use of flaps. This will include all five Flight Modes as well as full span camber changing. Landing Flaps and Their Connection View page S48 of the manual. The setting of the servo arm and the correct Sub Trim is critical to the operation of the flaps. Because the flaps move through as much a 90 degrees, the Sub Trim of the flap servos requires a large offset. 1. Remove the Flap control rods from either the servo arm or the flap horn. Landing Flaps on the Left Stick 1. Scroll the cursor over Butterfly and push the ROLLING SELECTOR. The XP9303 also provides for a specialized mix function which will completely eliminate that annoying bump that the airplane makes when you first pull the flaps down. That specialized mixing function is discussed later under Multi-Point Programmable Mixing. Motor Active with a Launch Flap and Elevator Preset Flight Modes, here we go again. Earlier we activated the Launch, Cruise, Land mode and placed them on the L3P SW. There are three flight modes on this switch. Although they are labeled Launch, Cruise and Land, you can actually use them for anything you want. 1. Move the Flap/Throttle stick to the bottom. Full Span Camber Adjustment Full span camber changing allows you to change the shape of the wing during flight. This function allows you to change the entire trailing edge of the wing. There is quite a current discussion concerning trailing edge camber and how it should be employed. Some argue that camber should be adjustable, from none to as much a ¼ inch. Others argue that there is only one setting for each airfoil that provides the greatest lift and that camber should just be on a switch. Simply on or off. This section will show you how to put camber changing on the left side slide. 1. Scroll the cursor over FLAP RATE and push the ROLLING SELECTOR. This section will mix the Ailerons to the Flap on the Left Side Slide and use the entire side slide (top to bottom) for Camber changing. 1. Move the Left Side Slide all the way to the top. Reflex Reflex is Latin for "go fast, go very fast." Reflex is lowering the drag of the wing by raising the trailing edge. It does not take much. Put a straight edge across the bottom the wing. The straight edge should contact the bottom of the wing at the thickest portion and at the trailing edge. Start raising the trailing edge. As soon as the straight edge touches the wing in three locations, (at the hinge line) you have all the reflex you need. Reflex is for going fast. Under cambered wings will benefit more from this than an airfoil with under camber. 1. Place the L3P SW in Cruise Mode (Middle position). Multi-Point Programmable Mixing Traditionally, mixing functions in computer radios only allow a linear mix between the master and the slave channels. As an example, when the aileron to rudder mix is activated, and you push the aileron stick all the way to the stop, it mixes in a pre-programmed amount of rudder deflection. With multi-point programmable mixing, the XP8103 radio allows you to insert up to seven different mix points anywhere on the curve. In other words, as you slowly push the aileron stick all the way to the stop, you could literally make the rudder waggle back and forth. In the case of model sailplanes, this allows you to mix a larger percentage of elevator compensation during the initial part of flap movement and less elevator compensation as flaps approach 90°. This completely eliminates that bump your airplane takes on approach as you pull the flap stick down. The XP9303 radio provides six extra programming functions that allow you to assign any slave to any master channel. The first of these additional mix functions allow the multi-point programmable mixing and is defaulted to mix Flap to Elevator. The remaining four provide the ability to do things like add additional aileron/rudder mix during launch, and automatically eliminate the aileron/rudder mix in reflex mode. To eliminate that annoying bump on approach when you pull down the flap stick, there is a very deliberate sequence of steps that you should follow. First, program the radio as indicated above for flap and elevator compensation on approach. Launch the airplane and adjust the elevator compensation until you achieve the proper glide path at full flap. Ignore the bump for now. Some individuals want the airplane, at full flap to continue on the same flight path before the flaps were lowered. Other individuals like the airplane to take a decidedly strong downward pitch when the flaps are lowered. This insures that you don't lose flying speed and stall your airplane. However, there is no situation where after pulling the flaps all the way down, the plane should pitch upward. This situation is unacceptable and should be avoided. The steps below will be used to determine the amount of Elevator compensation at full flap using the Butterfly Mix. At mid Flap stick, the sailplane will want to float up. Full Elevator compensation at full flap needs to be determined and marked on the fin/Rudder. Once the fin is marked, the elevator compensation in the Butterfly mode is reduced to zero and PROG. Mix1 will be used instead. 1. Scroll the curser over Butterfly in the program mode and push the ROLLING SELECTOR. Launch your aircraft and verify, at least three or four mistakes high, that the elevator compensation is correct at full flap. If it is not, land and adjust Point-0 until you have achieved the proper amount of elevator compensation with full flaps. Launch the aircraft again. Three or four mistakes high pull the flap stick down to mid flap and add or subtract Elevator Compensation until the flight path at mid Flap stick (Point-3) is also neutral. It takes a while to get this right. You are not going to get it on your first try. You may have to increase or decrease the mixing at POINT-3 until it is perfect. You may also need to adjust Point-5 and Point-4. Variations in the size of flaps and effectiveness of different elevators will require experimentation. Two meter aircraft respond well to a single but strong bump on the curve at POINT-4 and 5. Unlimited aircraft respond to a more gentle curve by adding additional compensation at POINT-2 and 1. When it is perfect, its sweet. Worth the price of admission. I recommend having a buddy pull the flap stick down while you are flying. By setting up the radio so that it is in PROG.Mix1 before launch, your buddy can pull the stick down until the vertical line on the graph is right above point 1 through 5. Because the mixing only works on one of these points, your adjustments upon landing will be MUCH more appropriate and you will nail this portion of the programming just that much quicker. Increasing (or Decreasing) Aileron to Rudder Mix During Different Flight Modes I trim my models to fly with little aileron/rudder mixing during normal flight modes. However, this means at launch, I have little if any rudder to recover from a bad throw. (Recall aileron controls roll, making it virtually worthless in this situation. Rudder controls yaw, like a rudder in the back of a boat, and is MUCH more important on launch) Its easy to increase the aileron/rudder mix during launch with the Launch Mode Switch. On the other hand, Aileron to Rudder Mix may need to be reduced in the Speed Mode. 1. Scroll the cursor over Ail to Rud M. and push the ROLLING SELECTOR. Programming the Motor So far, you have programmed the flight control surfaces using the Flight Modes. This next section will add control of the motor. There are two types of control available. Adjustable speed control with the Spoiler stick or Right Side Slider and ON/OFF speed control with a switch. If a switch is selected for speed control, the switch will control the motor an all flight modes. The same is true for the Right Side Slider. On the other hand, the spoiler stick can be used to control different things in different flight modes. Besides showing you how to program motor control on a switch or the Right Side Slide, this next section will show you how to change the Throttle stick during launch to a Flap stick during landing. Return to System Mode 1. Turn the radio off. Hold down the ENT button and switch the radio back down. Placing the Motor Control on the Right Side Slider 1. Turn the radio off. Hold down the ENT button and switch the radio back down. Placing the Motor Control on a Switch (In this example the Timer Button is used) 1. Turn the radio off. Hold down the ENT button and switch the radio back down. Placing the Motor Control on the Spoiler Stick when in Launch and Still Using the Spoiler Stick for Landing Flaps in Landing Mode 1. Turn the radio off. Hold down the ENT button and switch the radio back down. The Flap/Spoiler Stick works the motor in Launch Mode and the Flaps in Landing Mode. In all other modes, the Flap/Spoiler Stick is inhibited. How to Use This Programming 1. Flip the R3P SW to Neutral. (middle position) Other Things You Might Want to Try With This Programming In Cruise Mode: In Launch Mode (Motor available): In Speed Mode: In Thermal Mode: In Landing Mode: |
| V-tail Mixing V-Tail Mixing is no more difficult that a standard tail setup as far as the radio is concerned. In both setup's, you have to program and mix two control systems. The Rudder stick on both setups is the same. The Elevator stick on both setups is the same. The mixing of Aileron to Rudder is accomplished the same way. There is no magic here, but it does help to think in terms of controls systems instead of left and right ruddervator. What usually causes a poorly flying V-Tail is one that has been built out of square, a twist in the fuselage, or construction of control linkages that are not identical. The magic of a programmable radio is the ability to compensate for many of these type of construction deficiencies. The two tail servos are connected to the receiver as follows: elevator servo to left ruddervator and the rudder servo to the right ruddervator. (Check to make sure that each servo is operating in the correct direction.) 1. Return to the System Setup Mode by turning the radio off, pressing the ENT button, while simultaneously turning the radio back on. At this stage, the rudder stick (left) on your transmitter should move both ruddervators as rudders. The elevator stick (right) on your transmitter should move both rudder ruddervators as elevators. Make sure both control surfaces are moving in the proper direction in relationship to the transmitter sticks. If they are not, scroll the cursor over REV.SW and push the ROLLING SELECTOR. Reverse whatever servos are necessary to make sure that they move in the proper direction. (that would be limited to Rudder on the right and Elevator on the left. Control Throw Adjustments 1. Scroll the cursor over D/R & EXP and push the ROLLING SELECTOR. Travel Adjustment Now that you have the V-Tail control surfaces adjusted to appropriate amount of control throw, it is now time for their final adjustments. (The final adjustment of these control surfaces should be done at home on your work bench and not in the field.) The goal is to obtain travel each way from center that is as equal as possible. Unless you are an expert builder or awful darn lucky the control surfaces will not move equally. As an example, the elevator will move further up than it does down. The fine tuning of these control throws is now done using travel adjustment. For V-Tails, this is a critical adjustment. 1. Scroll the cursor over TRVL ADJ. and push down the ROLLING SELECTOR. Accurate adjustment of control surface deflection in both directions is critical to a good flying V-Tail. Adjust the amount of rudder to be mixed into the aileron stick (the right stick) by using aileron rudder mix described above. These instructions will only get you in the general area for the particular type, style and trim of your airplane. Use the dual rate function to modify the pitch or roll sensitivity of the aircraft to satisfy your personal taste. I highly recommend, that once you have determined the optimum setting, that you program both switch positions for dual rate and exponential to be exactly the same. This alleviates you from accidentally bumping a switch in flight and suddenly having an aircraft with different flying characteristics. Placing both the rudder and elevator controls in the right transmitter stick Perform the same mixing as discussed in any of the sections concerning Aileron to Rudder Mix. . V-tail Differential To enhance the turning performance of your aircraft, you can now change the difference between the UP and DN deflection of the control servos on either side of the V-tail. This is performed by changing the end point adjustments That we just spent so much time trying to make identical. To determine if your aircraft will benefit from differential, launch the aircraft and in slow level flight, level with the ground, move the left control stick (rudder only) on the transmitter. If the aircraft begins pitch up or down, you may wish to experiment with modifying the end point adjustments to compensate for that pitching motion. If the airplane pitches up with rudder only input both left and right, then you need to change the end point adjustments on both sides of the ruddervator to increase the amount of down movement of the control surface. (In the alternative, try less up movement.) The opposite is true if the aircraft pitches down. The need for V-tail differential is a byproduct of not understanding the exact ducalage between the V-tail and the wing. Ducalage is the difference in angle between the tail control surfaces and the wings. Even if the ducalage perfect, changes in the CG, area and aspect ratio of the v-tail and the angle between the v-tails may result in an aircraft that requires differential in the tail. Rudder deflection will not only cause the aircraft to yaw, it may also cause the aircraft to pitch up or down. This same effect may occur if your rudder or servo control horns are not perfectly placed over the center hinge line (creating a built in mechanical differential) or if you have other mechanical differences between the left and right ruddervator. Dual Rates adjust elevator or rudder throws, and both left and right ruddervators act in unison. End point adjustments now adjust the left and right ruddervators separately. For example with a Rudder turn only, the nose of your aircraft may pitch up. By modifying the end point to increase the amount of down throw of each ruddervator, up pitch can be eliminated. Different from Dual Rates, adjusting end points requires that you adjust the throw of both the left (elevator servo) and right (rudder servo) ruddervators separately. Re-enter the End Point adjustments discussed above. If the aircraft pitches up with a rudder turn, input more down deflection. The most likely result is that the aircraft will pitch differently with a rudder turn in each direction. It may pitch up in a left turn and pitch down in a right turn. If this is the case, it is relatively easy to fix. If the aircraft pitches down in a left Rudder turn, once on the ground input left rudder and increase the throw of the ruddervater that is in the up direction. If the aircraft pitches up in a left Rudder turn, once on the ground input left rudder and increase the throw of the ruddervater that is in the down direction. When individuals complain about the flight character of their V-Tail, the majority of the time is a V-Tail that needs some differential and different amounts of differential when turning in different directions. An aircraft that pitches up in a rudder turn is a real handful for any pilot. |
| The End What I found was rather interesting. The number one complaint was that the radio was still not flexible enough. (ie claims that not all switches could be assigned or that motor defaults could not be changed.) The number two complaint is that the radio is too complicated. Flexibility breeds complexity. There may not be any way around it. Because of the flexibility of the radio, a simple instruction sheet was just simply not possible. This manual is not the final say. It is just my way of giving something back to the hobby that has given me so much. It is just several ways to program the XP9303 for various types of sailplanes. There are other ways and I hope someone finds simpler means to accomplish the same results. If you have something different, please e-mail me or call me by phone. This document will be modified as something new comes up. If you provide a new concept, you will get credit for the idea in future versions. If you have any questions, please don't be afraid to call. Sherman Knight |
