Plane-Maker:

What Plane-Maker Does:A program called Plane-Maker comes with X-Plane that lets you enter your own aircraft design... any design you can imagine! Then, once you have entered all the physical specs of the airplane (weight, wing span, control deflections, engine power, airfoil sections, the works) X-Plane will predict how that plane will fly! Simply save the airplane in Plane-Maker like you would save a word-processing file and then openit in X-Plane to fly it! You can compress the airplane package and distribute it on the net for others to fly, or download planes that others have made as well. www.X-Plane.org is currently a good place to upload and download these planes.

What You Can Do With Planes You Make:ANYTHING YOU WANT!The EULA of X-Plane is pretty simple. It starts: "You can use X-Plane for anything you want!" One excellent use of Plane-Maker is to make the airplane of your dreams, fly it in X-Plane, and then upload it to the net for others to fly! Or, if your COMPANY has an exciting airplane, enter it into Plane-Maker, be sure it flies properly in X-Plane, and then put the .acf file on your web-site for customers or potential customers to download! Anyone that has X-Plane will be able grab the virtual version of your airplane and fly it in X-Plane! This is great because it will teach more people to fly your airplane (new customers?) and improve the currency of those that already fly it (safer customers?). Of course, you can also just use Plane-Maker to enter some plane that you already have and fly every day, simply for the purpose of keeping up your and stick-n-rudder and instrument skills.

Anyway, this chapter will give you the basics of entering an airplane in Plane-Maker, customizing it, and then releasing it on the net (either www.X-Plane.org or your own web site), for others to enjoy, possibly for the purpose of marketing your companies' design.

Using Plane-Maker to Make a Plane:We may, at some point, write the 200-page book needed to explain every detail of entering your own design in Plane-Maker, but here are the basics, with a good explanation on some of the common sticking-points, which is enough to get you started and working on your own. First, run Plane-Maker by double-clicking on it. Once it is running, go to the FILE menu and select OPEN AIRCRAFT. Select the INSTRUCTIONS folder and then select one of the EXAMPLE PLANE airplanes. (One of them has a 2-D instrument panel which is easiest tocustomize, and one of them has a 3-D cockpit which is harder to customize but gives you a 3-D virtual cockpit if you decide to make one). Once you have opened an airplane in Plane-Maker, simply go to every menu item in Plane-Maker, noting the hundreds of parameters ofthe airplane that you can change. Change any of these parameters that you like. (Want to try flying with twice the power? Twice the weight? Half the wing-area? Try it!)

Once you have changed a few parameters, it is time to save the plane and fly it. To do this, go to the FILE menu and select SAVE AIRCRAFT.

Now, launch X-Plane and select FILE:OPEN AIRCRAFT. Select the airplane you just saved in Plane-Maker and voila! You are flying your newly-modified airplane! This is the process for creating your own

aircraft and flying them in X-Plane.

Common Points Where help Is Needed:OK let's say you just opened an airplane and you want to check it for accuracy or modify it to be YOUR plane. Go to the STANDARD menu, VIEWPOINT item. Run down all the speed on the left and check them all against the POH (Pilot's Operating Handbook). These speeds are only used for marking up the airspeed indicator, NOT determining performance. You DO need to enter a valid Vne (Never Exceed speed)... and the more you enter accurately, the better, because while X-Plane does NOT use these speeds for PERFORMANCE prediction, it may use them for niceties like the STARTING speed for you when you select approaches and the like.

The Viewpoint location in the upper sort-of-left is the location of the pilot's viewpoint with respect to the reference-point on the craft. The reference point can be anything you like, just make sure you use that one point to measure ALL the locations on the plane. Long arm is feet aft of reference, lat arm is feet right of reference, and vert arm is feet above reference. Again: Choose any reference-point you like, as long as you use it to reference EVERYTHING on the plane.

Go to the PANEL-2D menu item. This is where you will design the 2-D panel for X-Plane, which is all you will use until you are really expert. Drag any instrument in that you want, and then click on the instrument to select it. Check the little box called 'COPILOT-SIDE SELECTION' for any instrument that you want to apply to the copilot panel. These instruments will drive on the second electrical bus, powered by the second battery and generator, and be given information by the secondpitot-static system as well. This lets you have pilot-side-only or copilot-

side-only failures.

NOTE: The plane will have one battery for every battery BUTTON you drag onto the panel. Drag in buttons appropriately.

NOTE: The plane will have one generator for every generator BUTTON you drag onto the panel. Drag in buttons appropriately.

OK now got to the SYSTEMS item. Enter the voltage of the LAST battery. Huh? Well, the last battery might have a different voltage than the others. This could be the case if you have a 28-V battery on the left bus, and only a 24-V battery on the right (essentials) bus.

Note that you can set a hanful of different hydraulic-pressure sources (engine-driven pumps, electric pump, ram-air-turbines) and what systems are powered by those systems, if any (flight controls, flaps, gear, etc).

Now go to the LIMITS-1 tab and LIMITS-2 tab. This is where you enterthe operational and limiting oil temperatures, pressures, battery and generator voltages and amperages, etc. Enter all these numbers carefully, and check them all against the POH.. this is what will make the plane be accurate in X-Plane!

Now go to the BUS tab. This lists a bunch of electrical systems, and the amperage they each draw, and the bus they each live on. If the bus that powers any of these guys goes down in X-Plane (battery and generator for that bus off, cross-tie off, no APU running for that bus) then you will lose that system. As well, your generator loads will be effected by the bus you attach each system to, and the amperage you

get it to draw.

If you are actually to do the airplane right, then you will need to research the current draw on each system in your plane, and the bus that each system lives on.

Now go to the FUSELAGE screen, SECTION tab.Enter the "fuselage body coefficient of drag" here.What do you enter?Ideally, the results of wind-tunnel testing or CFD.Don't got it? Try 0.025 for a decently-sleek plane.Make the number bigger, to add drag, if you are matching a known plane and find that your model is going too fast, and vide-versa.If you enter 0.00, then your fuselage has ZERO drag.If you enter 1.00, then your fuselage has the same drag as a theoretical big flat piece of plywood of the exact same frontal area as the frontal area of your plane. (No plane that draggy has ever been made.. thus the 0.025 starting-point).

Now go to the CONTROLS window.Check all those chord ratios (fraction of the total chord of the wing taken up by the control-surface) and deflections (how much do the controls deflect in the real plane?)

Once you enter your flap chord in fraction of total (what fraction of the total wing chord is taken up by the flaps) and type of flap, X-Plane will make a decent guess at the coefficient of lift, drag, and moment of the flaps.

If you find that the REAL plane slows down more than X-Plane

predicts when flaps are lowered, then maybe you need to increase theflap drag coefficient a bit. (Increase Flap Cd from maybe 0.07 to 0.08).

If you find that the REAL plane gives a lower stall speed than X-Plane predicts when flaps are lowered, then maybe you need to increase theflap lift coefficient a bit. (Increase Flap Cl from maybe 0.4 to 0.5).

If you find that the REAL plane does not pitch up or down like X-Plane does when the flaps are lowered, then maybe you need to increase or decrease the coefficient of moment. (Change Flap Cm from maybe -0.1 to -0.2 to pitch down more, or not pitch up as much, as the case may be).

Note the 'Flap Def Time, seconds'. This is critical to getting proper pitch-characteristics when the flaps are lowered. Measure off the real plane to get it right in the sim.

Now go to the TRIM SPEED tab. The 'trim up and down, relative to fullelevator deflection'. If the elevator goes up and down 30 degrees, and trim can run the elevator up and down 10 degrees, then you would enter 0.33 here. For "trim speed-ratio", you enter how fast the trim moves. For "trim tab adjust", you enter the controls deflection, in fraction of maximum, when the yoke is centered. This is, effectively, the built-in twist of the wing, or trim-tab on the airplane to get it to not roll or yaw in cruise.

Go to the LANDING GEAR item, GEAR DATA tab.Here, you will see something called "additional gear flat-plate area". X-Plane already looks at the frontal area of the struts and tires when the landing gear is extended and adds drag appropriately. But X-Plane

does not really know how much drag to add from the gear doors opening and disrupting the airflow over the no-longer-streamlied aircraft body. Enter that number here. Enter 0.00 if the gear doors close up once the gear is extended, and 1.00 if the additional drag from the gear doors opening is equivalent to putting a 1-square foot piece of plywood out there blocking the wind.

Now go to the Weight and Balance screen, TANKS tab.However many tanks you have, specify the ratio of fuel that each tank contains, and it's physical location. You better get the physical locationof the tank right, because X-Plane needs to know who is on the left and right sides to get the fuel-tank-selection right when you twiddle thefuel-tank-selection to left or right, and also X-Plane considers the inertial properties of slinging around fuel at various moment-arms fromthe CG, so be sure to get the fuel tank locations correct so that the airplane handles correctly!

Adding Airfoils to Your Plane in Plane-Maker:OK it should be pretty self-explanitory how to enter all the data into Plane-Maker... all the buttons are clearly labeled, but one question thatcomes up a lot is: How do I attach various AIRFOILS to my aircraft? Particularly at various DIFFERENT Reynolds numbers?

Well, like everything in X-Plane, this is pretty easy once you get the basics, and here they are:

First of all, X-Plane does =>NOT<= look at the =>SHAPE<= of the wing and then decide how much lift, drag, etc the foil will put out. X-Plane is NOT a computational fluid dynamics program. Instead, X-

Plane uses pre-defined airfoils that list the PERFORMANCE of any airfoil (lift, drag, moment) to predict how the plane will fly with that foil. So, how do you enter that performance? Pretty easy. Read the chapterin this manual on Airfoil-Maker, as it shows you how to enter the lift, drag, and moment of any given airfoil at any given Reynolds numbers.

Now, let's say that you have just create TWO foils in Airfoil-Maker, one for a NACA-2412 at Re=3 million, and one at Re=9 million. You might save the foils with names like "NACA 2412-Re3.afl" and "NACA 2412-Re9.afl". The Airfoil-Maker manual explains how to do this.

Now once you have done this, launch Plane-Maker and open your airplane. Then go to the "Expert" menu and then to the "Airfoils" item.Once in that window, tab over to the area containing the various different wings that your particular airplane has. Let's take the "Wings" tab, for example. You will notice that there are 4 airfoils listed for the "Wing 1" box. How could ONE wing have FOUR airfoils? Easy! You could have one type of wing at the tip, another at the root, with linear interpolation in between! You could also have one airfoil file for LO Reynolds numbers, and another for HIGH Reynolds numbers, with X-Plane interpolating in between! So that is FOUR airfoil files: Two Reynolds numbers at the ROOT (on the left) and two Reynolds numbers at the TIP (at the right). The lower Reynolds numbers go at the TOP of the box, the higher Reynolds numbers go at the BOTTOM. Just hold the mouse over the gray box to the left of each airfoil name to get a reminder of this if needed.

Now, for an example of your hypothetical plane, you would select (by clicking on the little gray box to the left of the airfoil names)"NACA 2412-Re3.afl" for the upper left, and

"NACA 2412-Re9.afl" for the lower left, if your wing uses a NACA 2412 at it's root, and you want X-Plane to give you accurate performance at Reynolds numbers of 3 and 9 million, with linear interpolation in between.

Ditto that, of course, for the wing TIP, and all the other foils on the plane.

How to Tune the Autopilot

OK, let's say that the autopilot in X-Plane is just not really doing exactly what you want. Maybe it is sort of wandering down the localizer, or wandering around in pitch when you want it to hold altitude. Maybe it is wandering around in heading, or perhaps flickering it's wings left and right madly as it tries TOO HARD to hold heading. Whatever the problem, you should be able to adjust the autopilot constants to get the plane to hold it's desired path more tightly.

How do you do this? By adjusting the autopilot constants in Plane-Maker. How do you do this? Read on!

First, load an airplane in Plane-Maker you want to adjust.Go to the EXPERT menu, ARTIFICIAL STABILITY screen.Go to the AUTOPILOT tab.Check the button called 'USE CUSTOM AUTOPILOT CONSTANTS'.When you do this, a set of numbers come up that specify the autopilot constants for your airplane. Here is what they mean, and how to adjustthem!

First, let's talk about HEADING. Look at the SECOND screen down.

ROLL ERROR FOR FULL AILERON:

When you fly a REAL plane, you decide on a roll angle to make aturn, yes? You then decide to deflect the ailerons a certain amount to ACHIVE the bank angle you want, right? Question: Let's say that you WANT 45 degrees of bank, and the plane is currently at 0 degrees of bank. Do you put in ALMOST NO AILERON AT ALL? NO WAY! You put in a GOOD HEALTHY DOSE of aileron! Why? Because you are a big fat 45 degrees away from your desired roll angle! Conversely, if you are at 29 degrees of roll, and you WANT 30 degrees of roll, so youonly need ONE MORE DEGREE OF ROLL, do you put in FULL AILERON to get to 30 degrees? NO WAY! YOU WOULD OVERSHOOT FOR SURE! You look at the controls and say 'gee, I amonly a LITTLE off of my desired bank angle, so I will only put in a LITTLE BIT of aileron. Now, how many degrees off of your desired bank angle do you have to be to put in FULL aileron? 1? 10? 100? However many degrees you must be off from your DESIRED roll angleto put in FULL aileron, THAT is the number you should enter in the 'rollerror for full aileron' button. If you put in a really SMALL number, then the autopilot will put in FULL aileron for even the TINIEST of roll errors! This is no good! This will cause the plane to over-control and flutter madly left and right like an over-caffineted pilot! On the other hand, if you enter a really HUGE number here, like 100 degrees, then the autopilot will hardly put in any aileron input at all! In that case, the plane will always wander along off course a bit, because it will never care enough to GET BACK ON COURSE. Now, any smart pilot might

say: "I WOULD NEVER ENTER FULL AILERON, EVER". Fair enough. But realize that the autopilot WILL be limited to about 50% travel or so, and will AUTOMATICALLY back OFF of the controls as the airplane speeds up, just like you would. So what you are really entering here is how aggressive the ailerons are. If you find the plane really does NOT steer aggressively to the command bars, then you probably need a SMALLER number here, because you are telling the autopilot: "You should only require a SMALLER deflection to really crank in the ailerons!" Conversely, if the plane flutters left and right likea plastic bag in a 50-knot wind, then you need to tell the autopilot to NOT crank in so much aileron! To do that, enter a LARGER number here, so the autopilot waits for a LARGER error to develop before responding with so much force. 30 degrees might be a decent numberto enter here. It says that if the roll angle is off by 10 degrees, the plane will apply one-third aileron to correct when at low speed. Not a bad idea.

ROLL PREDICTION:

When YOU fly, you look INTO THE FUTURE to decide when to add, and back off, of the flight controls. This is simply anticipation. How far into the future should the autopilot anticipate? If the plane is wandering left and right slowly, always behind the game, overshooting and then wandering slowly off in the wrong direction like a tired drunk driver, then clearly it is NOT anticipating enough. In that case, you need to INCREASE the the roll prediction, so that the autopilot ANTICIPATES more. If, however, the airplane starts flopping back and forth hysterically every frame, then you have clearly told it to anticipateTOO much! You need to enter a SMALLER roll prediction! 1 second is a decent roll prediction... after all, when I fly a plane, I would say I

really enter my controls based on WHERE THE PLANE WILL BE IN ONE SECOND, not where it is right now.

ROLL TUNE TIME:

In the real plane, you TRIM OUT any loads with trim if you have it. How long do you take to run the trim? Probably more than just a fewseconds! But, if you let the autopilot wait TOO long to trim out the loads, then it is often kind of slow and late to give you what you want. Enter maybe 5 seconds here.

LOCALIZER CDI GAIN:

OK this should seem familiar. Let's say that you are ONE DEGREE off the localizer as you fly an ILS. How many degrees of HEADING CORRECTION are called for to correct for that? If you correct only ONE degree, then you will just be flying right towards the airport, never intercepting the localizer until you get to the transmitter on the ground! If you see a ONE DEGREE error in your localize (what is that, one dot on the CDI?), then I would enter about 10 degrees of heading correction to go ahead and nail that HSI NOW. So, enter a number here that is the number of degrees of heading change that you want the autopilot to pull for each degree of error on the localizer (which is the same as saying for each dot of CDI deflection). I think that 10 works fine.

LOCALIZER CDI PREDICTION:

If you are a good pilot, you do NOT fly an ILS based on where the CDI IS. When pilots fly so lamely as that, they wander around in S-turns all the way down the localizer! We see it all the time. If you are

any GOOD, then you fly the plane based on where the HSI CDI WILL BE IN THE NEAR FUTURE! How far in the future? Well, a few seconds at least. The MORE you want the autopilot to ANTICIPATE, the BIGGER the number you enter here, since this is the CDI anticipation. If your plane is wandering back and forth slowly across the localizer, always S-turning, then I bet that you need to enter a bigger number here! More anticipation to prevent endless S-turning from always being behind the game! But, if you enter TOO big a number, then the plane might NEVER JOIN THE LOCALIZER, because it is anticipating SO FAR AHEAD that it turns away from the localizer AS SOON AS THE NEEDLES COME ALIVE, since it is shying away to avoid an over-shoot.. that is TOO MUCH ANTICIPATION! About 2 or 4 seconds should be reasonable numbers here.

So, in summary, enter the number of degrees of bank error that should give very strong aileron response in the ROLL ERROR FOR FULL AILERON. Enter the number of seconds the system should anticipate in the ROLL PREDICTION, the number of seconds requiredto trim out the load in the ROLL TUNE TIME, the number of degrees of heading change per degree localizer error in the LOCALIZER CDI GAIN, and the number of seconds of anticipation of HSI CDI deflectionin the localizer CDI prediction.

FIRST, FORGET ABOUT THE ILS AND JUST SEE IF YOU CANGET THE THING TO PERFECTLY HOLD HEADING. Tweak the ROLL ERROR FOR FULL AILERON to give as strong a response as you like, and the ROLL PREDICTION to give the anticipation that you want. Fly the plane around IN HEADING MODE, snapping your heading bug left and right and tweaking those constants until the

plane follows the heading bug PERFECTLY. THEN, AFTER THE HEADING MODE IS PERFECT, adjust the localizer values while flyingILS's to get the localizer down. If you get S-turns across the localizer, you need MORE localizer prediction. If the thing never even grabs the localizer, always turning away from it, then you need LESS localizer prediction. The thing is clearly over-anticipating.

OK Now let's talk about PITCH. This discussion will be exactly the same as roll, really.

PITCH ERROR FOR FULL ELEVATOR:

Well, you can guess what this is. This is how much error between desired and actual pitch is required for full elevator deflection.Now, remember that the autopilot will automatically reduce the control deflections as the plane speeds up, and will limit to maybe 50% control deflection, so you do not need to worry about the system REALLY going to FULL deflection. Now, FORGET ABOUT THE ILS FOR A MINUTE and JUST FLY VERTICAL SPEED OR PITCH-SYNC MODE. If the plane is really sloppy about getting the nose up to track a new vertical speed and just takes too long to get there, then you need to enter a SMALLER 'pitch error for full elevator', so the plane will be more aggressive with the elevator. But, of course, if the plane starts flapping about madly, then you need to enter a LARGER 'pitch error for full elevator', so you are telling the plane 'do NOT deflect the elevator so much unless you have a LARGER error between the actual and desired pitch'. You should put the autopilot in PITCH SYNC MODE and then hold the CWS button down and quickly pitch the noseand then let go of the CWS button. How quickly does the autopilot work to hold that new pitch? If it is slow and sloppy, then you need to

enter a smaller number here to make the thing more aggressive, and the reverse is true as well.

PITCH PREDICTION:

Now, if you are a good pilot, then you will PREDICT where the plane WILL BE SOON and enter flight control accordingly. Maybe 1 second of anticipation is good. Try that. If the plane is always wandering up and down when trying to hold a given vertical speed, always a few steps behind the game, then more anticipation is clearly called for, (a larger number) and if the plane is always afraid to GET where it needs to be, always resisting motion towards the desired pitch, then it is probably anticipating TOO much, and a smaller numberis called for! You really need to tune these numbers in pitch and roll modes, or maybe heading and vertical speed modes, to get them all perfect, with nice, snappy, precise autopilot response, BEFORE you take the thing down the ILS. One second might be an OK value to enter here.

PITCH TUNE TIME:

This is the time require to trim, clearly.

5 seconds may be fine.

If you enter too SMALL a number here, then the plane will constantly be wandering up and down as it plays with the trim, because it will always be TOO QUICK TO HIT THAT TRIM! In the real plane, you wait until you are SURE before you roll in the trim. So entera pretty large number here, like 5 or 10 seconds.

GLIDESLOPE CDI GAIN:

For each degree of glideslope error, correct with this much change in pitch. If you enter 5 here (a reasonable value) then the autopilot will pitch up 5 degrees for each degree it is low on the glideslope. The greater the number you enter here, the more the command bars will move to grab that glideslope!

GLIDESLOPE CDI PREDICTION:

If you are a good pilot, then you anticipate where the glideslope WILL BE IN THE NEAR FUTURE as you make your pitch commands. If you do NOT anticipate enough, then you will always be going up anddown all the way down the glideslope. If you anticipate TOO much, then you will never GET to the glideslope, because you will always be shying away from it as soon as the needle starts to close in. 8 secondsmight be a decent prediction.

PITCH DEGREES PER KNOT:

In flight level change mode, if your plane is 1 knot slow, how much will you pitch down to get that knot back? Enter that number here. I use 0.2.

SUMMARY:

OK here is the summary. Remember that there are 2 distinct things here: The amount you MOVE THE COMMANDS BARS, and

the amount you MOVE THE CONTROLS TO CAPTURE THOSE COMMAND BARS. So, if you see the COMMAND BARS are not beingtoo smart, you can see what variables to set below.But, on the other hand, if you see that the COMMAND BARS are just fine, but the AIRPLANE JUST ISN'T TRACKING THE BARS, then youneed to set the variables listed below to grab the bars. Just remember that there are 2 steps:

Step 1: Decide how to move the bars (CDI gain, CDI prediction)Step 2: Decide how to move the controls (pitch & roll error,

prediction)

And remember that there is one number that controls how HARDwe try to GET to our target (CDI gain, roll and pitch error for full deflection... think of it as a SPRING CONSTANT) and one number thatcontrols our ANTICIPATION (CDI prediction, roll and pitch prediction... think of it as a damping constant).

OK here is the little table:

AMOUNT TO MOVE THE COMMAND BARS ON THE ILS:localizer CDI gain, glideslope CDI gain

AMOUNT TO ANTICIPATE THE COMMAND BARS ON THE ILS:localizer CDI prediction, glideslope CDI prediction

AMOUNT TO MOVE THE CONTROLS TO GRAB THE BARS:roll error for full aileron, pitch error for full aileron

AMOUNT TO ANTICIPATE THE ATTITUDE TO GRAB THE

BARS:roll prediction, pitch prediction

TIME TO TRIM THE FORCES:pitch tune time, roll tune time

OK, so now that you see what each number DOES, let's show you how to set these things up quickly. First, launch X-Plane. Now open your plane. Now go to the SPECIAL menu. Now go to the SET AUTOPILOT CONSTANTS menu item. You will notice that a window comes up with (you guessed it) all the numbers we just talked about! Now here is where it gets really fun: You can change these numbers AS YOU FLY to get the autopilot constants just right for each individualplane. Just be ware: These numbers will be LOST the second you exit X-Plane or open some different plane! These numbers are for experimentation only! Once you have the numbers you want, you better write them down on a piece of paper and enter them into Plane-Maker where you can actually SAVE them!

Another note: You might enter a really aggressive autopilot system that has HUGE anticipation and HUGE gains and TINY maximum pitch and roll errors for full deflections. That would be a verystrong, very aggressive autopilot that may SEEM to work perfectly. Buthere is the problem: As soon as you start flying with a LOW FRAME RATE, the plane will start shaking violently on autopilot because that autopilot is not running FAST ENOUGH to see the very-rapid RESULTS of it's overly-strong inputs! SO, if you want the autopilot to actually work ALL THE TIME, you need to load up the scenery or weather to really slow the machine down to it's minimum frame-rate while you tune the autopilot! Only then can you enter constants that

will ALWAYS work, because the EXTRA frame-rate people may get later could never hurt. I recommend just setting 3 broken layers of clouds and plenty of buildings in the rendering options screen to get a low frame-rate.

How to Design an Artificial Stability System

Let's say you are doing a VTOL or fighter that needs an artificial stability system. You can design a simple such system in Plane-Maker pretty easily. How? Read on!

Load an airplane in Plane-Maker.Go to the EXPERT menu, ARTIFICIAL STABILITY screen.This is where you can enter control-system constants to make your plane feel stable even though, in reality, it isn't.This is especially common in fighter jets and helicopters... fighters are most maneuverable if unstable, and heilos just have nothing to naturally MAKE them stable!

So we design control systems to MAKE THEM SEEM STABLE. These control systems typically do this by ADDING SOME INPUT IN ADDITION TO YOUR STICK INPUT to make the plane do what you want. A common case of this in the civilian world is the yaw damper... your feet still move the rudders, there's no doubt about that, but the yaw-damper system ADDS SOME ADDITIONAL RUDDER DEFLECTION FOR YOU TO DMAP OUT THE ROATION RATES OF

THE PLANE. How much rudder does it add? Well, that is a decision made be the controls-system engineer... in this case known as: "YOU".Let's imagine a yaw damper. The goal is to add some rudder deflection to whatever the pilot hammers in with his feet to stop aircraftrotation... this is seen in high-end Mooneys and most jets. So ask yourself this: How much rudder do you WANT to add to stop rotation? FULL rudder? Just 1/10 of the max rudder deflection? Obviously, if theplane is only wagging its little booty a LITTLE BIT, you only want to add a LITTLE rudder to stop it. But, if the plane is shaking at a high rate, then you better put in a LOT of rudder to put a stop to it NOW. So how do we decide how much rudder to put in? Well, there are plenty ofways, but in X-Plane, we say that we enter some fraction of the rudder input PER DEGREE PER SECOND OF ROTATION RATE. So, imagine the plane is wagging its little tail (from turbulence, varying crosswind, the pilot stepping on the rudder, WHATEVER) at 90 degrees per second. (Now let's THINK about that for a second!!!!! HOLD YOUR HAND IN FRONT OF YOUR FACE AND PRETEND IT IS AN AIRPLANE. NOW ROTATE YOUR HAND THRU 90 DEGREES OF HEADING CHANGE IN 1 SECOND. THAT IS 90 DEGREES PER SECOND. As you see, it is a moderate rotation rate, but not a really huge rotation rate. However, when you are in the real airplane, 90 degrees per second of tail-wagging will feel like a LOT. (Kicking the rudders a bit in a Cessna 172, for example, will shake its little booty at about 35 degrees per second). So, let’s say that 90 degrees per second is so much rotation rate that we are willing for the control-system to put in FULL RUDDER to oppose it. That means that if the plane is rotating at 90 degrees per second, we want to put in FULL rudder to oppose that motion, and at 45 degrees per second we want to put in HALF rudder to oppose that motion, and at a measly 9 degrees per second we want to only put in 1/10 rudder to oppose that

motion. At the 35 degree-per-second tail-wag of a 172, the control system would put in as much as about 35% rudder deflection to oppose tail-wagging and yaw-stabilize the plane. This does not sound like an unreasonable constant. So what do you enter in Plane-Maker to make it happen? Well, for the "heading: target sideslip" you might just enter "0" (the plane always tries to stabilize at 0 sideslip) and for "fraction deflection per degree difference" simply enter "0" (the system is not trying to achieve a desired sideslip, only DAMP OUT the tail-wagging by opposing ROTATION RATES) and for "fraction deflection per degree per second" enter "0.0111". Why 0.0111? Well, take that 0.0111 and multiply it by 90 (the rotation rate that we would apply FULL rudder at) and you get 1.00.. or, translated: "FULL rudder deflection". Put another way, if you want full rudder at 90 degrees per second yaw rate, simply take 1.0/max yaw rate and you will get 1/90 or0.011. This is a reasonable yaw-damper constant. Try entering it for the 172, save the plane in Plane-Maker, load it again in X-Plane, and pop the rudders left and right: you should see the plane damps out faster, as would a real one if such a yaw damper were installed in reality.

Now, maybe you want even MORE stabilization... try entering 0.1in the "fraction deflection per degree per second". Now, THINK about what that means. That means that if the plane is rotating thru 10 degrees per second, the rudder will move fully to oppose it. (10 degrees per second times 0.1 control per degree per second = 1.00, which is FULL DEFLECTION. Move your hand at a rotation rate of 10 degrees per second. This means it should take 9 seconds to move your hand thru 90 degrees. That is a SLOW rotation rate. Yes, with a constant of 0.1, even this SLOW rotation rate will be opposed by FULLrudder. YIKES!!!!!!!!! If you just BREATHE on this airplane now it will

kick FULL rudder to oppose it! Yikes! This is scary, because IF YOU TAKE THIS THING INTO TURBULENCE I GUARANTEE THE AIR WILL KICK YOU AROUND AT WELL OVER 10 DEGREES PER SECOND ROATION RATES, SO I GUARANTEE YOU WILL SEE =>FULL<= RUDDER DEFLECTION FIRST ONE WAY, AND THEN THE OTHER, AS THE PLANE WAY OVER-REACTS TO EACH ANGULAR ROTATION INDUCED BY THE TURBULENCE BY KICKING FULL RUDDER TRYING TO OPPOSE THAT ROTATION! So, as you can see, a constant of 0.1 is really pretty high. Now, to giveyou an idea of how bad it can get, I have actually seen a plane where someone entered a constant of 3.0. THIRTY TIMES HIGHER than thishypothetical case. Think about what this means: For a rotation rate of 1/3 degree per second (in other words, it takes 270 seconds (4.5 minutes) to move thru 90 degrees of heading, an EXTREMELY LOW ROTATION RATE, the system would put in FULL OPPOSITE RUDDER! HOLY COW! That means that the plane has even the tiniest, slowest-imaginable HINT of rotation in a given direction, THE RUDDER SLAMS HARD OVER TO THE STOP TO COUNTER IT. Needless to say, any time this plane entered even the slightest hint of turbulence, the rudder would slam from one stop to the other in a wildly exaggerated effort to counter the turbulence. Ugh! If you must kill a fly buzzing around you in a china-shop, don't go after it with a chainsaw. The results won't be pretty. This particular plane handled OK if there was no turbulence: Since nothing ever came along to ROTATE the plane, the flight controls never had to move to OPPOSE THAT ROTATION, but as soon as the slightest imperfection came along to move the plane (in this case turbulence, though it could easilybe the pilot kicking a flight control, a bird-strike, an engine-failure, a bumpy landing, flying into changing winds.. ANYTHING. One thing that you can ONLY learn by actually getting your pilots license and

getting your butt in the sky is that it is a VERY IMPERFECT WORLD UP THERE. The plane is constantly barraged by all manner of imperfections, perturbations, and external winds and forces, and this must be EXPECTED and anticipated in the design much like with a BOAT.

Now let's apply what we have learned to PITCH stability: Say your plane is not very stable in pitch and you want to lock it down a bit.(First of all, in X-Plane 8.30 RC-2 and later you can slide the "control addition" sliders in the "Joystick" screen second tab to the right a bit toadd some artificial stability to help stabilize the plane a bit. This simplyengages a system that I designed for you to help stabilize the plane). But let's say you DON'T want to use my system to stabilize the plane, but really design your own to mimic the one actually installed in the real plane! Well, enter maybe 20 degrees for the target angles of attack (enough to stall the plane) enter 0.1 for the fraction deflection per degree difference (if the angle of attack is 10 degrees off, then the plane applies full elevator to capture the desired angle of attack.. a very aggressive but not insane constant) and enter 0.05 for the "fraction deflection per degree per second" (if the nose is coming up at20 degrees per second, then the system will apply full elevator to stop it). These are some pretty aggressive constants (a lot of elevator is brought in to counteract a small amount of motion) but I have my reasons:

1: The plane needs to have lower rates in pitch than in yaw. Why? Because if you yaw a plane a bit, not that much will change: the vertical stabilizer, which is being broadcast to the air, is small! But, if you PITCH the plane a bit, then the WHOLE WING AND HORIZONTAL STAB is shown to the air... the effect will be a lot greater

than in yaw where only the vertical stab is offset, because the wing is so much bigger!!!! So, we got a lot more effect for each degree of angle of attack than we do of sideslip, so we need lower pitch rates than yaw rates to keep within comfortable (safe) G-loads, so we enter HIGHER constants in pitch than yaw to really work hard to counter those pitch rates. Also, there is another reason we can enter higher constants than you think:

2: I cheat. X-Plane will automatically REDUCE THE CONSTANTS as you speed up, because it knows that at high speed it is better to enter smaller control deflections to keep from busting anything! So the constants you enter here are only fully applied down near the stall where control authority is mushy. The controls relax and phase out as the indicated airspeed (air pressure on the controls) builds up.

Now, are you ready to see this scheme in practice? Open up my VTOL in Plane-Maker ("File" menu, "Open Aircraft", "Austin's Designs : Austin's Personal VTOL" and look in the "Expert" menu : "Artificial Stability" screen. Notice that I have only LOW-SPEED constants here, designed to phase out rotation rates to make the thing easy to fly. Look at the rotations I shoot for with full-scale stick deflections in hover: Max of 30 degrees pitch, 45 degrees roll, and 45 degrees PER SECOND ROATION RATE in yaw. And now you know what the 0.02 and 0.01 do as well. Now get into X-Plane and load up this little bird (it starts off with thrust vector at 90 degrees, straight up). Add power and rise up off the ground and work on your hovering. Slideleft and right. Fore and aft. Up and down. Do it with small control deflections.Now, see that little switch on the panel called "ART STAB"?

Turn it OFF to fly WITHOUT stability augmentation.VIVA LA DIFFERENCE! (for a more extreme case, try turning off the art stab in my "Death Trap" at 300 knots)

Finishing the Plane: Custom Cockpits, Paint, and Sounds:OK, you now know that you can create, modify, upload, and download airplanes for X-Plane, but once you make an airplane in Plane-Maker, you will notice that the instruments are all X-Plane standard, the sounds are all X-Plane standard, and the airplane is simply grey.

What do you do to take your plane to the net level of customization, with custom paint, instruments, and sounds?

Well, it's pretty easy!

Exit X-Plane.

Now, in your operating system, go into the INSTRUCTIONS folder andfind the EXAMPLE PLANE folders.

Open the 'Example plane 3-D' folder. We will look in there to see what sorts of things you can customize on your custom plane.

First you see the EXAMPLE.ACF... that is the actual aircraft file that contains all the data that defines the airplane. You can email this file tofriends or whatever for them to try flying your design. This is what you save in Plane-Maker.

Custom Paint for Your Plane:But now let's take it to the next level: Look at the various _paint.bmp files. These are the paint-jobs for the plane. Simply paint them any way you like in Photoshop to make them perfect for your particular design. You may save the files as either BMP or PNG. Notice the_prop.png file. You should be able to guess what that is when you open it up and look at it. Of course you can modify that as well. For any plane you make, simply follow the naming convention you see here in the instructions folder: name your paint-jobs xxxx_paint.bmp and xxxx_paint2.bmp, where 'xxxx' is clearly the name of your aircraft.Each bitmap may currently be up to 1024x1024 in size. All bitmaps must be powers of 2 in size. (2, 4, 8, 16, 32, 64, 128, 256, 512, 1024). To control what part of the plane lives in what bitmap 9siunce you have up to 2 bitmaps), go to the EXPERT menu in Plane-Maker, TEXTURE REGION SELECTOR window.

Custom Panels and Instruments for Your Plane:Now look in the INSTRUCTIONS:EXAMPLE PLANE-BASIC:COCKPITfolder. In there you have just a few custom panel and altimeter files. Needless to say, these particular custom files are just the tip of the iceberg. Look in the RESOURCES:BITMAPS:COCKPIT folder to see the approx 750 instruments you can customize for your airplane. Each of the instruments you see there may be copied to your aircraft folder and customized just like the few sample cases you see in the EXAMPLE PLANE 3D folder! If you fly X-Plane and open this aircraft, you will see the instrument panel and altimeter are stunningly ugly... that is just to make it obvious at a glance they are custom, non-standard instruments. So, simply follow the model you see here, but using the instrument names and folders in RESOURCES:BITMAPS:COCKPIT, and you can customize ALL of X-

Plane's instruments for your plane! Easy!

Now, let's do an example. Let's say you have a plane and you are not happy with the autopilot annunciator on your airplane. Maybe it is too small, or does not have quite the right look and feel, or maybe you have an aircraft with an older annunciator panel that does not look the way you want. In this case, you must start off by copying the instrument you want to modify from the X-Plane default instruments over to your aircraft. To do this, look for the following files in the following folders: "resources:bitmaps:cockpit:autopilot:console_filled_GA.png" and "resources:bitmaps:cockpit:autopilot:console_filled_GA-1.png". Those are the autopilot annunciator consoles. You can open the PNG files in Photoshop to look at them. Now, make a folder called "cockpit:autopilot:" in your own aircraft folder, just like we did for the Example airplane in the instructions folder. Now, in your operating system, copy the files "console_filled_GA.png" and "console_filled_GA-1.png" from "resources:bitmaps:cockpit:autopilot:" to "cockpit:autopilot:" in the aircraft folder.

Do you see what you are doing? X-Plane will now see these files in the aircraft folder, and use THEM INSTEAD of the default instruments whenever it tries to draw an autopilot annunciator panel for general aviation airplanes. Now, you can simply modify these files in photoshop (the ones in the "cockpit:autopilot:" in the aircraft folder!) tomake the autopilot annunciator look however you like. If you have photos or other images of the REAL instruments, you could copy and paste them from your reference image files right into the "console_filled_GA.png" and "console_filled_GA-1.png" files. Of course, you may have to scale and tweak and drag to get the

reference image files you have of the instruments to fit the .png files you are editing for X-Plane.Now let's do a more complex example. Let's say you want to do a new EFIS system. First, in Plane-Maker, drag the EFIS artificial horizon, HSI, VVI indicator, localizer-deflection-indicator, glideslope-deflection-indicator, DME-indicators if desired, Mach-number indicators, and any other little instruments into place in Plane-Maker to form the EFIS system that you want to simulate. It won't look exactly like the EFIS you want to simulate, but it should be a pretty decent idea. Fly it in X-Plane to see if it works about right. Now, take note of the exact name of each instrument you selected by clicking it in the panel-editor in Plane-Maker. Now exit Plane-Maker and, in your operating system, copy all the instruments you just dragged into your EFIS into the custom instruments folder you created for your airplane, following the steps listed above, and the example shown in the 'instructions:Example-Plane-Basic:cockpit' folder in your copy of X-Plane. Once you have copied in all those files into your own aircraft folder (with all the folder hierarchies maintained, of course, just like with the sample plane!) then you can edit each of those files as you see fit with Photoshop or any other program... copying in images from photos or other graphics programs as well, if you like. Just be sure, of course, to:->keep all the proportions the same, even if the total image size changes->save as PNG or BMP, which are the formats X-Plane uses.

As well, if you like the autopilot annunciator of some OTHER aircraft you have, then of course you can simply copy the autopilot annunciator folders and images from the airplane you LIKE into the

one that you would LIKE to have the custom annunciators. In other words, if you have a BARON that has an autopilot annunciator that youlike, and KingAir that has one that you don't, then simply look inside the "cockpit:autopilot:" folder in each aircraft, and copy the "console_filled_GA.png" and "console_filled_GA-1.png" files from the baron to the KingAir... and then voila! You have the new autopilot annunciators in the KingAir, if you select that instrument for somewhere in the panel of the KingAir. Using this technique, you can copy custom instruments from one plane to another easily.

So, now you see how you can easily modify and any instrument for any airplane in X-Plane, and copy modified instruments around between airplanes.

Custom Sounds for Your Plane:Look in the EXAMPLE PLANE 3D:SOUNDS folder to see some custom SOUNDS this plane has. As you can see, all you need to do ismake your own WAV file and name it as the airplane name plus " engn1.wav" for the left engine, for example, drop it into the SOUNDS:ENGINE folder and you are ready to fly with a custom engine sound! Do you want to see a complete list of ALL the sounds your can customize? OK! Look in the RESOURCES:SOUNDS folder. Just like the RESOURCES:BITMAPS:COCKPIT folder is a list of all the INSTRUMENTS you can customize, the RESOURCES:SOUNDS folder contains a list of all the SOUNDS you can customize by putting them in your aircraft folder! Follow these simple conventions and you can have all the custom sounds you like, different for each plane!

Custom Weapons and Slung Loads for Your Plane:

Want to make your own missiles and bombs for your plane? No problem! Run Plane-Maker and go the WEAPONS window in the EXPERT menu and make and save a weapon. You will be saving a .wpn file that should go in the WEAPONS folder. Now look in the EXAMPLE PLANE 3D:WEAPONS folder. This is where you can save your own weapons... the .bmp file is simply the paint that goes on the weapon. You can have a good handful of weapons on your plane.

You can do the same for slung loads (a Jeep carried by a Black-Hawk,for example). Look at Example_slung_load.obj. This is an object that can be selected as a slung payload in the SETTINGS:WEIGHT AND BALANCE window in X-Plane. These objects can be saved in the 3-D editor AC3D. Now look at the EXAMPLE_SLUNG_LOAD.PNG... that is the custom texture for any slung load you might carry, which is specified in the OBJ file.

Custom 3-D Cockpits and Bodies for Your Plane:OK now we kick it up to the top level: Making custom 3-D cockpit and bodies for your airplane with a 3-D editor. This takes us beyond the basic 2-D cockpits and simple shapes of the standard airplanes and up into the level of total customization and accuracy.

Look at EXAMPLE PLANE 3D:EXAMPLE_COCKPIT.OBJ. This is the 3-D virtual cockpit, if you want your plane to have one. Hit control-O in X-Plane (or whatever key you have decided to use in the INSTRUCTIONS:KEYS folder) to go into virtual-3-D-cockpit mode in X-Plane, and use the a-s-d-w-r-f-arrow keys and mouse to move around in the 3-D cockpit. Look at EXAMPLE PLANE 3D:EXAMPLE_COCKPIT_TEXTURE.PNG. This is the texture that will

be used in the (totally optional) 3-D virtual cockpit, if you decide to make one.

The next question is: How do you create OBJ files? Well, OBJ files are3-d objects that X-Plane can draw. As such, you need an editor that can create 3-D objects and save them in the OBJ format. AC3D is such an editor, and you can get that at www.ac3d.org.

So, how do you do this? Well, check out scenery.x-plane.com for full documentation, but here it is in brief:

X-Plane uses the OBJ file-format, which can be saved in AC3D. (www.ac3d.org)There is a plug-in that saves AC3D files in the OBJ format, so you can simply make your objects in AC3D, then save them as X-Plane object files and they will be ready to fly!

Now, let's say that you want to use LightWave rather than AC3D.This is a little bit of a problem, because LightWave can use MORE than one texture per object (for speed, X-Plane uses only ONE texture per object!) and LightWave can NOT save in the OBJ format.But never fear! You can do all your work on the OBJ in LightWave, then save the file in 3ds format.Then, open the 3ds file in AC3D and apply the (SINGLE!) texture to the object... once you do that, simply save the file as an OBJ and that file is ready to be read as a custom cockpit object, miscellaneous object, object for scenery, or the like.

Distribution:OK, now that you have your airplane done, it's time to get it out there!

Go to www.X-Plane.org and create a free account... it takes 5 seconds. Now, make a single folder that holds your airplane, and a folder within that folder that holds any custom airfoils you may have made, if you have not already. People often upload airplanes BUT FORGET TO UPLOAD THEIR AIRFOILS. DON'T DO THAT. IT DOESN'T WORK.So, be sure to configure the acf file inside a folder with a recognizable name, put any custom airfoils you made inside a folder called 'airfoils', which lives inside the main folder for the airplane, and zip the whole thing in a zip file. Windows users can use WinZip, mac users can option-click on the folder and chose "Create Archive" and the job is done. Now, just upload your plane! Cool! This is a great way to let others see your design, especially for commercial purposes, like letting the world test-fly your companies plane virtually... at zero cost to you!

Summary:OK, you now see how to make, modify, upload, and download custom airplanes to fly in X-Plane.You know how to customize the paint, instruments, sounds, weapons, slung-loads, and even 3-D cockpits in X-Plane.NOW GET TO WORK!!!!!!