8: Expert Essays

8: Expert Essays

Tuning the Handling in X-Plane

OK so you have X-Plane set up and flying, but it seems to be too sensitive in pitch or pulls to one side. How do you tune this?

OK first let's get the obvious out of the way: You should have your joystick calibration done. See the setup chapters of this manual for instructions on this. Want to see if you really are properly calibrated or not? OK. Go to the 'Settings' menu, 'Data Input and Output' window, and select the 'Joystick ail-elv-rud', right-most check-box. This will send the aileron, elevator, and rudder input from your joystick to the cockpit text display. Once you do this, you will be able to see the various stick deflections at the top-left of the screen. When you center the stick and pedals, do the aileron, elevator, and rudder joystick inputs read around 0.0? When you go full left and forward, do they read around -1.0? When you go full aft and right, do they read around 1.0? If so, then your joystick is calibrated. If not, then your joystick is NOT calibrated! No wonder the plane is not flying right!!!! So, the FIRST thing to do is be sure your stick is calibrated properly. If it is, and the plane is still not flying like you want, then read on!

OK, once you have the stick calibrated and can prove it with the data output as indicate above, then see if the plane flies the way you like it. No? OK, then let's look at the first level of control-response tuning. Go to the 'Settings' menu, 'Joystick and Equipment' window. There, you should look at the CENTER of that window. Move the stick around. Moving the stick and pedals around should move little rectangles around, and if you center the stick, then the rectangles should go to zero size, if your hardware is perfect. Since no hardware on earth really IS perfect, though, simply CENTER your hardware and hit the 'Center the Yoke and Pedals and Hit This Button' button. This will mark the hardware as centered. If you have PFC hardware, you will have little buttons across the bottom of the window that you can hit to set the center position of each axis. So, now you have the ability to set the center position of each axis. Did you do it right? Quit guessing and out! Close the joystick window and move your flight controls to the centered position and see if the data output is around 0.000 when the controls are centered. Is the data output around 0.000 when the controls are centered? If so, then your hardware works decently and you set the center-point successfully. If not, then your hardware is not too good or you did not properly set the center point. So, now fly the plane. Does it handle ok? No? OK, then read on while we go to the next level.

OK, if you are still not happy with flight-handling, then look at the 'Settings' menu, 'Joystick and Equipment' window, 'Center' tab, and go to the 'Control Response' sliders on the left. If the left-most 3 sliders are fully left, then the control response is linear. 50% stick deflection in your hand will give 50% control-deflection in the sim. Perfectly linear. 100% stick deflection in your hand will give 100% control-deflection in the sim. Now, perhaps you think the plane feels too responsive in the simulator. If so, then drag the sliders all the way to the right. This will be a non-linear response. 0% stick deflection will still give 0% control deflection, 100% stick deflection will still give 100% control deflection in the sim, but now with a difference: 50% stick deflection in your hand might only give 15% control deflection in the sim. In other words, while the HARD-OVER ROLL RATE in the sim will remain UN-CHANGED no matter what these sliders are set to, you will be able to get fine control for smaller, partial deflections, since the flight controls will move LESS for the small-to-moderate stick deflections in your hand. This will give you nice fine pitch control, and nice slow, detailed, rolled control. So, set those sliders and see how it feels. Is it OK now? No? OK, then read on:

OK, the next level is Stability Augmentation. If you still think the plane is too squirrely or over-sensitive, then drag those sliders all the way to the right. What will happen? Now, X-Plane will automatically counter-act any stick input you give to some degree, resisting rapid or large deflections in pitch, heading, and roll. Basically, it is like always having an autopilot on that smooths things out for you. It's fake and stupid, so I don't like it, but in the absence of a perfect flight-control system and g-load and peripheral-vision feedback, this can help smooth the airplane out for you. So, try flying with those sliders at various different places, but full-LEFT should be most realistic: No artificial stability added.

So, does it fly just right now? Still pulling to one side or the other? OK, we have done everything we can in the sim, now it's time to tweak the airplane. If the REAL plane is pulling to one side or the other, you bend the little trim tab on the aileron one way or another. This bending of the aileron trim tab counter-acts any imperfections in the shape of the airplane or dynamics of the propwash or mass-distribution inside the plane. Well, you can do exactly the same thing in X-Plane: Bend a trim tab a bit one way or the other to make the plane fly true. How do you do it? Still pretty easy. Exit X-Plane. Open Plane-Maker. Go to the 'File' menu and open the plane that is pulling left or right. Go to the 'Standard' menu and then to the 'Control Geometry' screen. Go to the 'Trim and Speed' tab. Go to the very RIGHT-HAND column of numbers in the top box of the screen: 'Trim Tab Adjust'. This is simply how much the trim tabs are bent on each axis. Top is elevator. Middle is aileron. Bottom is Rudder. (look on the left side of the screen). A value of 0.00 means the trim tab is not bent at all. A value of 1.00 means the tab is bent so far that the control is FULLY-DEFLECTED by the trim tab (!) way too much I am sure. So, you want to bend the trim tab A LITTLE BIT. Maybe 0.05 or at most 0.10. This would correspond to being enough to deflect the controls 5% or 10% due to the trim tab. Now, which WAY do you bend it? Positive or negative? Well, positive is up and right. So, if you want the plane to roll RIGHT a bit more (or STOP rolling left!), then enter a POSITIVE number for the aileron. Ditto that with rudder if you want the plane to pull RIGHT a bit more, and ditto that with elevator if you want the plane to pull UP a bit more. Tweak the trim tabs, save the plane, exit Plane-Maker, run X-Plane, go flying, and you should notice the plane pulls one way or another based on how you bent the trim tabs. Tune as needed to get the plane to fly as straight as you want.

Tuning the Frame-Rate in X-Plane

Two of the emails I often get are as follows:

"WOW! X-Plane is so fast! I get 100 fps on my computer! Amazing! This is so much smoother than other flight sims!"and"WOW! X-Plane is so slow on my computer! What should I do?"

Why does this happen?

Well, of course many people today run 1-ghz Pentiums with 512 meg of RAM and 64 meg of VRAM, while others run dual-processor 3,000 mhz machines with 256 meg of VRAM and 4 GIG of RAM... and there can be MORE than a 10x difference between them in speed, since the RAM speed and quantity, motherboard speed, video card speed, bus speed (very important!) and many other things cause performance differences between computers.

Now, here is what so many people seem to NOT know, even though it is fundamental to understanding computer performance:

ONE limit is how much RAM you have (video, and system!)the other limit is how much SPEED you have (CPU, and video card, and BUS!)

Which of these matters to you? Well, coming up short in EITHER category will slow you down.

So, the way to get maximum speed is to have:-Enough VIDEO RAM to keep all the textures and geometry on the video card (the more you have, the higher rendering options you can select)-Enough SYSTEM RAM to hold X-Plane (1 gig is OK, 2 gig is better)-All the speed you can afford.

So, if you do not have enough VIDEO RAM on your video card to handle X-Plane at the Rendering Options you have set, then you are GOING TO RUN SUPER-SLOW, NO MATTER HOW MUCH CPU YOU HAVE.

So, if you do not have enough SYSTEM RAM to handle X-Plane at the Rendering Options you have set, then you are GOING TO RUN SUPER-SLOW, NO MATTER HOW MUCH CPU YOU HAVE.

Conversely, if you have all the RAM in the world, but if your computer CPU is slow or your video card speed is low, then you will of course get low performance.

So, given whatever machine YOU have, how can you get the most from X-Plane?

That is the question to ask, and here are the answers:

First the basics: YOU HAVE TO BE ABLE TO TELL HOW FAST X-PLANE IS RUNNING. Run X-Plane and go to the SETTINGS menu, then DATA INPUT & OUTPUT window, and check the right-hand box in front of "FRAME-RATE", thus sending the frame-rate to the screen in flight. Now you can see how fast you are running, in the "freq /sec" output on the far left. This is called "frames per second" or "fps".

15 fps is poor.100 fps is insanely high.30 fps looks fine.

Studies show that at 60 fps or above, your SUB-CONCIOUS MIND forgets that you are looking at a simulator, and thinks you are flying.

What frame-rate are you seeing on YOUR computer?Not high enough?OK, lets see how to make it faster!

First the easy one, hat is sort of cheating: Let's set the WEATHER to an easy condition to render. Go to the ENVIRONMENT menu, SET WEATHER screen. Set the cloud types to CLEAR LAYER for max speed, or HIGH CIRRUS or LOW STRATUS for good speed. SCATTERED OR BROKEN OR OVERCAST take a TON of CPU time to run.

Set the visibility to about 5 miles or so. Higher visibility takes MORE CPU to run, because you see more stuff!

Nothing else in the weather screen will affect frame-rate, but clouds and visibility affect it a LOT.

So, setting NO clouds and NO precipitation and LOW visibility will make the sim run faster, but of course this is totally cheating because you might want the sim to run faster WITH clouds and good visibility, because that is when flying is most fun!

So now let's get to the GOOD stuff:

Go to the SETTINGS menu, RENDERING OPTIONS screen. We will work this windows from top to bottom.

Look at your TEXTURE RESOLUTION. This setting determines how detailed all the thousands of textures in X-Plane are, and therefore much VIDEO RAM you will use. As long as you have plenty of VIDEO RAM, you can set this as high as you want with NO LOSS IN FRAME-RATE, but as soon as you set the texture resolution to require more VRAM than you have, YOUR FRAME-RATE WILL DIE! How do you tell how much VRAM X-Plane uses? Easy. Look at the BOTTOM of the rendering options screen and X-Plane tells you how much VRAM is required at it's current settings. If this number is greater than the RAM on your video card, then you are asking to get slow performance. How much RAM is on your video card? You need to go to your operating system to find out, and of course this will be a bit different for all the various Mac, Windows, and Linux OS's out there. Use Google as needed if you don't already know how to find the VRAM available on your particular computer. Once you know the VRAM on your computer, lower the texture resolution in X-Plane until X-Plane uses about what you have, not too much more

NOTE! X-Plane can use MORE VRAM for the buildings and roads and forests! So you should really set the texture resolution so that the VRAM report at the bottom of the screen is a bit LOWER than your actual VRAM!

NOTE! You can, in some cases, use MORE VRAM than your video card has, and X-Plane will still run fast, because a lot of the RAM can be "cached away" in the system with no speed penalty if it is not often accessed by the computer! For example, it is OK to have the texture of desert sand cached away off the video card, for example, if no desert sand is visible to you because you are not flying over the desert! But, if you have only 128 meg of VRAM on your vide card, but the texture res is set such that you need 256 meg of VRAM, then the computer will constantly be moving RAM on and off the video card (between the video card RAM and the system RAM) to draw each frame of scenery. THIS IS VERY VERY SLOW. Thus, you must set the texture res LOW ENOUGH TO AVOID THIS.

NOTE: After you change the texture resolution, you should re-start X-Plane for all the changes to take effect!

NOTE: Just put the texture resolution on it's lowest setting, exit the sim, re-start it, and note the frame-rate. Then raise the texture detail up one level and repeat. Keep doing this until the frame-rate decreases. This is the point where you are using up all your VRAM! Back the texture resolution off to one level lower than that and restart to fly.

Now look at the screen resolution in the rendering options screen. It uses up some VRAM, but not much. It uses up some video card processing power as well, but not too much. Set the resolution as you see fit. Probably 1024x768 or whatever it takes to fill your monitor.

Now look at the anti-alias level: This can make things VERY slow since it draws the scenery many times to average the result. You should turn this down to NONE, if you are not happy with your frame-rate.

Now look at the all-important "forest density", "number of objects", and "number of roads" settings. These have a HUGE impact on frame-rate. Set these to NONE for speed. Dialing any of these things up will take BIG hits on performance, because they draw thousands of objects, and gobble RAM and CPU in the process. Forests and objects just draw SOOOOOOOO many objects at their maximum level, that you really will want a TOP-end machine to handle these settings at their maximum.

Dial down the 'world detail distance' if you want. This is sort of a last-ditch effort to save CPU. Though it will cause objects to 'pop' into place in front of you, which is not very nice to look at! So I never move that setting away from it's default.

UN-CHECK the cars/birds/hi-res-planet textures/hi-detail-runway-environment for speed. Most of these do NOT make too much of a difference in speed, but they make a little difference, so you can turn them off.

Now for some big ones: USE PIXEL SHADERS. This one can really hurt your frame-rate, because your video card might not be new enough to really handle this well. If you turn this on, check your framerate after closing the RENDERING OPTIONS window. It might be hurt! A new video card is called for in that case, since your video card just does not have the power to handle the new graphics technologies very well.

Now, below that, you have the 'volumetric fog' and 'reflective water'. These options can have HUGE impact on frame-rate, because the fog is computed every pixel, and the water-reflections require the whole world to be rendered TWICE! So use these option with care. The higher you set your reflective-water level, the more detailed the reflections, and the slower the sim will run!

"Number of cloud puffs" has a HUGE impact on frame-rate when you have scattered, broken, or overcast clouds, but you already know to avoid those if you are not getting good frame-rate!

The other settings in this window don't really effect speed too much, as long as you leave the EXPERT RENDERING OPTIONS alone, as you should.

So there you have it. Follow all the instructions above and you can get good frame-rate with X-Plane even on a slower, older computer, as long as you have proper OpenGL drivers installed on it! See the web page of your vide card manufacturer for instructions on that.

How to Set Up Advanced Networks

Lets say that you want to have 2 computers running X-Plane, one with the instrument panel on the pilot's side, and one with a panel on the copilots side. (we call this a master machine and a copilot's machine setup)Or maybe 2 extra panels.. you have a center radio-panel as well.Or maybe an Instructor Operator's Station to control weather and time and failures. (we call this an IOS)Or maybe a separate computer for an out-the-window view. (we call this an external visual)Or maybe a multiplayer session to fly formation with your friends.or maybe a copy of EFIS-App (instead of X-Plane) to show Avidyne displays.Or maybe all of the above, all at once!

How do you do it?

Well, if you have multiple computers, simply assign each of them an IP address that has the first 3 numbers the same, a unique number for the last quadrant of the IP address, and a subnet mask of 255.255.255.0. Once each of your computers has an IP address that meets this requirement, your computers may be set up something like this, for example:

192.168.0.1 master machine (joysticks plugged in here)192.168.0.2 Copilot's machine (acf with copilots instrument panel used here)192.168.0.3 IOS (instructor station to initiate failures, set weather, move the plane, etc. GREAT for training!)192.168.0.4 external visual, left view192.168.0.5 external visual, center view192.168.0.6 external visual, right view192.168.0.7 EFIS-App, which has an Avidyne PFD and MFD.

Get your LAN set up so that the computers can talk to each other and you have a network that is ready for an X-Plane multi-computer setup. Install X-Plane on each computer. (Scenery and everything!) Install EFIS-App on any computer that shall be used to show high-accuracy Avidyne displays.

Now, on each of these computers, go to the 'Settings' menu, 'Net Connections' window. Select it and look at the various 'Inet' tabs. These screens allow you to configure a multi-computer X-Plane system. On each computer, simply check the box describing the job of each computer, and enter the IP address of whatever OTHER computers are called for by the text description, and you should be ready to fly!

NOTE: SET UP THE MASTER MACHINE FIRST. The master machine is the one with the controls plugged into it that runs the flight model. Do the master machine first, because it will AUTO-CONFIGURE some stuff in the external visuals and stuff, saving you a little time, as the master machine gets the various other computers on the network into line. Once you have done that, THEN configure the external visuals, cockpits, and IOS... just check each of the 3 tabs in the 'Net Connections' window to check all the available settings.

NOTE: ONCE THE NET CONNECTIONS ARE CONFIGURED, MAKE THE RENDERING OPTIONS CHOICES FROM THE IOS IF YOU HAVE ONE, MASTER MACHINE IF NOT. All the rendering options will go from the IOS to the MASTER to the EXTERNAL VISUALS AND COCKPITS automatically, which is kind of convenient since it keeps all the machines in sync... just think of it this way: Just like the IOS controls the weather and time of day, it also controls the rendering options to control how the world looks. This stuff is all set in the RENDERING OPTIONS window in the SETTINGS menu.

Now, a commonly-asked question by people that are really pushing for a thorough simulation is: "How do I set up a co-pilots instrument panel in X-Plane?" It's easy. Here's how:

Get TWO monitors for the computer showing your instrument panels, make BOTH monitors appear as ONE EXTENDED DESKTOP IN WINDOWS. (This is important for speed! Go to the desktop properties and then to the ADVANCED tab and then to the NVIDIA control panel and then be sure that BOTH monitors appear as ONE extended Windows desktop! If you don't do this, the sim will run SLOOOOW!) Once you have set both monitors to one extended desktop (2048 x 768, prolly) then launch X-Plane on that machine and set it's res to 2048 x 768 on that computer and load an airplane with a cockpit that is 2048x768 pixels... with different instruments on the right side to be the copilot's panel! Cool! Now, if you do NOT have any big 2048x768 panels with different copilots-side instruments handy, or time to make such a panel, then just say the second monitor is a clone of the first in Windows. Sigh. This is not as good as a real copilot-side display with different HSI OBS settings and the like, but it is 95% as good for almost no effort.

Now, if you do NOT want to run ONE copy of X-Plane at 2048x768 with TWO monitors sprouting out of that one computer to do your copilot panel, you can use a DIFFERENT computer for the copilot-side panel.

Do it this way:

Get 2 computers and 2 copies of X-Plane, and a single crossover Ethernet cable, or a pair of Ethernet cables and an Ethernet hub.

Install X-Plane on each computer.

Connect the computers to form a simple LAN, as you always would in Mac or Windows, as the case may be.

Make a cool airplane, with the PILOTS SIDE INSTRUMENT PANEL just the way you like it. Save it with a name like: "coolplane.acf"when you are done, simply make a copy of the airplane, and name the copy "coolplane_copilot.acf". Notice you just added the "_copilot.acf" on the end.

Save that copilot's-side airplane in the same folder as the pilot's-side plane.

Open the "coolplane_copilot.acf" in Plane-Maker, and tweak the instrument panel all out to be perfect for the co-pilots side.

Now you have 2 copies of the same plane, each with its own instrument panel, and the names "coolplane.acf" and "coolplane_copilot.acf".The .acf files are in the same folder, right beside each other.

Now simply copy that whole aircraft folder from one of your computers over to the other, putting the aircraft folder in the same place in the second (copilots) copy of X-Plane.

Now simply fire up X-Plane on each computer, go to the SETTINGS menu, and then to the DATA INPUT OUTPUT window on each computer, and select INET 2 tab.

Check the IP ADDRESS OF EXTRA VISUAL/COCKPIT #1 (THIS IS MASTER) button on that computer, and enter the IP address of the copilot's machine.

On the COPILOT'S machine, check the IP ADDRESS OF MASTER MACHINE (THIS IS EXTRA COCKPIT), and enter the IP address of the pilot's machine.

Now, on the lower left, click on the 'aircraft name reading suffix' and enter (can you guess it? if you are smart, you should) "_copilot".That means that NO MATTER WHAT PLANE YOU OPEN ON THE PILOTS MACHINE, this computer will add "_copilot" to the name of the plane that it tries to open!

Now, on the PILOTS machine, open the "coolplane.acf"... if you set everything up right, then the pilots machine will send all the appropriate data to the copilot's machine (because you checked the "ip address of external..." box), the copilots machine will get the message (because you checked the "ip address of master..." box) and the copilot's machine will apply the name "_copilot" to the aircraft name (because of the name suffix you entered), and open the copilots plane on the copilots machine. A plane that has a copilot's instrument panel, if you did your job in Plane-Maker.

OK that was a GENERAL description of how to set this stuff up, now how about a few checklists for you to run off as you set up your multi-machine sims:

One-Machine, One-monitor setup:Install X-Plane and run it.Done.

One-Machine, Two-monitor setup, second monitor is IOS:This is the case where you have an IOS on one screen, panel on the other. WARNING: THIS MAY RUN POORLY, SINCE THE IOS WILL SUCK UP VALUABLE CPU POWER FROM THE SIMULATOR! BE SURE TO LEAVE THE IOS MAP IN THE 'HI-SPEED' TAB TO MINIMIZE THIS NEGATIVE EFFECT!SETTINGS menu:RENDERING options screen.DRAW COCKPIT ON SECOND MONITOR: check ON.

Two-Machine: One master machine, one IOS:Fire up each copy of X-Plane

IOS machine: SETTINGS:NET CONNECTIONS:INET-2:IP OF MASTER (THIS IS IOS):enter IP addy of master machine.

master machine: SETTINGS:NET CONNECTIONS:INET-2:IP OF SINGLE-STUDENT IOS (THIS IS MASTER):enter IP addy of IOS machine.

Two-Machine: One master machine, one external visual:Fire up each copy of X-Plane

master machine: SETTINGS:NET CONNECTIONS:INET-1:IP OF EXTRA VISUAL (THIS IS MASTER):enter IP addy of extra visual machine.

extra visual machine: SETTINGS:NET CONNECTIONS:INET-2:IP OF MASTER (THIS IS EXTRA VISUAL):enter IP addy of master machine.

Two-Machine: One master machine, one external cockpit:Fire up each copy of X-Plane

master machine: SETTINGS:NET CONNECTIONS:INET-1:IP OF EXTRA VISUAL/COCKPIT (THIS IS MASTER):enter IP addy of extra cockpit machine.

extra cockpit machine: SETTINGS:NET CONNECTIONS:INET-2:IP OF MASTER (THIS IS EXTRA COCKPIT):enter IP addy of master machine.

Three-Machine: One master, one IOS, one external visual:Follow items from various checklists above.

Four-Machine: One master, one IOS, one external cockpit:Follow items from various checklists above.

Four-Machine: One master, one IOS, one EFIS-App:Follow items from various checklists above, only check INET-3:IP OF EFIS-APP on the master machine instead of IP of external cockpit.

NOTE: IF YOU HAVE A SIM WHERE YOU ARE DRIVING A COPY OF EFIS-APP, then the MASTER machine should probably be the front and center VISUAL. This will give the most responsive visual to the pilots, and let you drive either EFIS-App or an External Cockpit for the instruments, letting you show Avidyne displays or standard-siz instruments.

ULTIMATE SETUP: MANY VISUALS, IOS, EXTERNAL COCKPIT, AND EFIS-APP:And now, finally, the checklist for the ultimate X-Plane sim: One master machine, one external cockpit for standard-6 instruments with dual-monitors to show copilot instruments or one copy of EFIS-App to show Avidyne displays, one IOS, and 5 visuals. I recommend a setup like this:

Machine #1: 192.168.0.1, IOSMachine #2: 192.168.0.2, far-left external visualMachine #3: 192.168.0.3, medium-left external visualMachine #4: 192.168.0.5, center visual, is master machineMachine #5: 192.168.0.6, medium-right external visualMachine #6: 192.168.0.7, far-right external visualMachine #8: 192.168.0.8, cockpit: can run either X-Plane or EFIS-App

You can tell from the checklists above how to set these up, but I make one important note: By having your CENTER VISUAL BE THE MASTER MACHINE (with controls hooked up and flight-model run), on that master machine you can check the box for external cockpit and/or EFIS-App and enter 192.168.0.8, and on machine 192.168.0.8 you can run either X-Plane for a standard-6 cockpit, or EFIS-App for an Avidyne cockpit. This lets you build ONE sim that can run BOTH configurations.In each of the EXTRA VISUAL machines, go to the SETTINGS menu, RENDERING OPTIONS screen and enter a lateral offset in degrees... negative on the left side, positive on the right. If each screen has a field of view of 45 degrees, then enter -90 for the far-left lateral offset in degrees, -45 for the medium-left, 45 for the medium-right, and 90 for the far-right.

Flying Helicopters

An oft-wondered question is: How do I fly helicopters?

Well, let's start by addressing how we fly them in the real world, and then move to how we do that in X-Plane.

You can find all manner of different helicopter layouts in reality, but let's talk about the standard configuration here: A single overhead rotor with a tail rotor in the back. Here's how it works: First, the main rotor provide the lift needed to lift the heilo. How does it do this? Well, the helicopter ALWAYS MAINTAINS THE SAME ROTOR RPM for the entire flight! The lift from the main rotor is only varied by ADJUSTING THE BLADE PITCH OF THE MAIN ROTOR BLADES. So, let's say that the one-and-only operational rpm of a heilo is 400 rpm. When the plane is sitting on the ground, the rotor is turning 400 rpm, and the pitch of the blades of the rotor is about ZERO. This means that the rotor is putting out about ZERO lift! Because the blades have zero pitch, they have very little drag, so it is very easy to move them through the air. In other words, the power required to turn the rotor at its operational RPM is pretty minimal. Now let's say you are ready to go flying. You do this by pulling UP on a handle in the cockpit called the "collective". When you do this, the blades on the rotor go UP TO A POSITIVE PITCH. (all the blades on the main rotor do this together at once, "collectively"). Of course, they are putting out a lot of lift now, since they have a positive pitch. But, equally obviously, they are harder to drag through the air now, since they are doing a lot more work! Of course, since it is a lot harder to turn the blades now, so they start to slow down... THIS WOULD BE CATASTROPHIC SINCE YOU CAN'T FLY WHEN YOUR ROTOR IS NOT TURNING, so at that point any modern heilo will AUTOMATICALLY increase the throttle however much it has to, to maintain the desired 400 rotor rpm. So, to summarize, this is the sequence for getting a heilo in the air, which will be an important first step in your crash:

1: You are on the ground, the collective handle is FLAT ON THE GROUND. This means the rotor pitch is flat, with minimum drag and zero lift. IN X-PLANE, FLAT COLLECTIVE CORRESPONDS TO THE THROTTLE BEING FULL FORWARD, OR FARTHEST FROM YOU.

2: The automatic throttle in the heilo is obsessively watching that rpm, adjusting the throttle as needed to hold exactly 400 rpm. Since you are on the ground, and the collective pitch is flat, there is little drag on the blades, so the power required to hold this 400 rpm is pretty low.

3: You decide to start crashing. You do this by RAISING THE COLLECTIVE UP BY PULLING IT UP FROM THE FLOOR OF THE HELO. IN X-PANE, THIS MEANS YOU START EASING THE THROTTLE ON YOUR JOYSTICK BACK DOWN TOWARDS YOU. This increases the blade pitch on the main rotor and therefore increases the lift... but also increases the DRAG on the rotor a LOT! The rotor RPM begins to fall below 400 rpm (OOPS!), but the auto-throttle senses this and loads in however much engine power it has to, to keep that rotor rpm at exactly 400 rpm.

4: You keep pulling in MORE collective until the blades are creating enough lift to raise the heilo from the ground! The auto-throttle keeps adding power to keep the rotor turning at 400 rpm no matter how much you raise or lower the collective in your attempts to fly the heilo.

OK, so now we are in the air, and your first crash is beginning.. how can you delay this inevitability for a few moments? Well, the answer is: ANTI-TORQUE PEDALS. The main rotor is of course putting a lot of torque on the heilo, causing it to spin in the opposite direction (for every action there is an equal and opposite reaction. Twist the ROTOR one way, the heilo will twist the other way). This rotational torque on the heilo is countered with thrust from the tail rotor. Just push the left or right rudder pedal on your CH-Products Prop Pedals that you hopefully bought to get more or less thrust from the tail rotor. If you don't have rudder pedals, then twist your joystick for anti-torque control. If your stick does not twist for yaw-control, then X-Plane will do a decent job of adjusting the tail-rotor lift to counter the main-rotor torque in flight. Incidentally, the tail rotor is geared to the main rotor SO THEY ALWAYS TURN IN UNISON. If the main rotor loses 10% rpm, then tail rotor loses 10% rpm. They are geared together. So how does the tail rotor adjust its thrust if it cannot change its speed? Same as the main rotor: by adjusting its pitch, and it is that tail-rotor pitch that you are controlling with your rudder pedals or twisty joystick.

OK, so you are in the air and adjusting the COLLECTIVE PITCH of the main rotor (with your joystick throttle) to hold 10 feet in the air and adjusting the tail-rotor pitch with anti-torque pedals (with your rudder pedals or twisty stick) to keep the nose pointed right down the runway. Now what? Well, you now need to wiggle the joystick left, right, fore, and aft to steer the heilo around. How does this work? Well, if you move the stick to the RIGHT, then the rotor blade will INCREASE its pitch when it is in the FRONT of the heilo, and DECREASE its pitch when it is BEHIND the heilo. In other words, the rotor blade will change it's pitch trough a full cycle every time it runs around the heilo once. In other words, it changes it's pitch from one extreme to the other 400 times per minute (7 times per second) if the rotor is turning at 400 rpm. No, I don't know how it does this without flying to pieces either. Now, while it SEEMS that the right name for this might be the "helicopter-destroyer", the fact that moving the stick sends the blade pitch through one CYCLE every rotation of the rotor blades means we call the control stick the CYCLIC stick. So you have your collective, cyclic, and anti-torque controls. Now, let's talk about the cyclic a bit more. When you move the stick to the right, the rotor increases pitch when it is in the part of its travel that is in FRONT of the heilo. Why? Well, because that will increase the lift on the FRONT of the rotor disc. This will cause the rotor disc to TILT to the RIGHT. (remember: gyroscopic forces are applied 90 degrees along the direction of rotation of the gyroscope). Now that the rotor is tilted to the RIGHT, it will of course drag the heilo off to the right as long as it is producing lift. So here is the fascinating thing: the rotor on many heilos is totally free-teetering. It has a completely "loose and floppy" connection to the heilo. It can conduct ZERO TORQUE (left, right, fore, and aft) to the body of the heilo. Maneuvering is only achieved by the rotor tilting left, right, fore, and aft, dragging the top of the heilo underneath it in that direction. So the heilo body is dragged along under the rotor like livestock by a nose-ring, blindly following wherever the rotor leads.

So, now that you are using this information to hover perfectly, push the nose down to tilt the rotor forwards. The lift from the rotor acting above the center of gravity of the heilo will lower the nose of the heilo, and the forwards component of lift from the rotor will drag the heilo forwards as you fly along.

So that's how you fly heilos. Pray that nothing breaks, if you want to live.

Flying in Space

OK we have covered how to go low and slow. Now let's go high and fast. If you hop in the 'Japanese Anime' in the 'Science Fiction' folder, you can hit the gas, pull up, and find yourself in space quickly, and if you are good, you will be able to level off at 500,000 feet at 15,186 knots orbit! The speed is labeled as 'V', in green, below the attitude indicator. Now, you may notice that you ARE able to control the plane in pitch, heading, and roll. Now, given that there is no air over the flight control surfaces, how is that possible? The answer is: Maneuvering rockets. Often called RCS (or Reaction Control System) rockets, these are small rockets placed at the extremities of the spacecraft that fire in opposition to each other to rotate the craft about all axis. With these rockets, you can maneuver in space, and without them, you simply tumble. Obviously, the Japanese Anime has such rockets, and many other planes do not. So, how do you ADD such rockets to some spacecraft of your OWN design? Pretty easy! Go into Plane-Maker and open the craft you want to put in space. Now go to the 'VTOL or Helo Controls' window in the 'Expert' menu. Look in the lower-left corner of the window for the 'Extra Inputs for Jets' section. Notice that you see spaces for PUFFERS. What are Puffers? Well, the AV-8B Harrier has little hair-dryers at it's extremities that puff air in one direction or another to maneuver the plane while in hover. This is really exactly the same thing as the RCS on space-ships, so it is what we use in X-Plane to maneuver craft in space as well. (Of course, in the Harrier, these puffers are driven by air pulled off the compressor of the jet engine, and in spacecraft, the RCS is driven by the combination of volatile fluids or gases. So the METHOD by which puffers work is radically different between a Harrier and spacecraft, but the end result is the same (little jets of gas that spurt one way or another to rotate the craft about each axis). So, enter the maximum pitch-moment that your RCS system can generate in pitch, roll, and yaw to get the RCS system for your spacecraft simulated. The moment is equal to the force times the distance from the center of gravity. So, if the rocket puts out 200 pounds of force, and is located 10 feet from the center of the spaceship, then that rocket provides a MOMENT of 200 x 10 = 2,000 foot-pounds. If you have TWO such rockets to maneuver the craft in pitch, then enter 4,000 foot-pounds, of course. If you do not know how much to enter, try entering an amount equal to the WEIGHT of your vehicle. This is the same as saying that the rockets are EQUIVALENT to putting the entire weight of the ship on a 1-foot lever arm, or 1/20 th the weight of the ship on a 20-foot lever arm an amount that should be just fine for maneuvering!

As well, you can input longitudinal, lateral, and vertical rockets, which are used to push the craft fore and aft, left and right, and up and down.

Now, once you have entered all these stats on the rockets to get the craft to pitch, roll, yaw, and translate up/down, left/right, and fore/aft, close the window and save the craft and exit Plane-maker and try it out in X-Plane. Can you maneuver in space now?

One problem you may still have is that it is simply pretty hard to maneuver the craft in space because there is no damping of any sort. The plane may tend to tumble out of control. In that case, you need a fly-by-wire system! Full instructions for designing fly-by-wire systems are included elsewhere in this manual.

Flying the Space Shuttle

Read this chapter before attempting Space Shuttle landings in X-Plane if you want to live!

What do you think the first rule of flying a glider is?Think about it.

The first rule of flying a glider is: "Never come up short".When you are bringing a powered plane in for landing, if you think you are not quite going to make it to the runway, it is no big deal just add a bit of power to cover the extra distance! Need a little more speed maybe? Again no problem: Just add power.Gliders play by a different set of rules, though: There is no engine to provide power, so when setting up your landing, you must always have enough altitude and speed to be able to coast to the airport, because if you guess low by even one foot, you will hit the ground short of the runway, crashing. You must NEVER be low on speed or altitude, because if you EVER are, you have NO WAY of getting it back: a crash is assured. (The exception is thermals, or rising currents of air, which can give efficient gliders enough boost to get the job done, but thermals will typically provide less than 500 feet per minute of vertical speed, not enough to even keep a lightweight Cessna in the air!)Now with the Space Shuttle, it is certainly true beyond doubt that it has engines. Three liquid-fuel rockets putting out 375,000 pounds of thrust EACH, to be exact. (To put this in perspective, a fully-loaded Boeing 737 tips that scales around 130,000 pounds or so, so EACH ENGINE of the orbiter could punch the Boeing straight up at 3 G's indefinitely and that is not even considering the solid rocket boosters attached to the Shuttle's fuel tank that provide MILLIONS of pounds of thrust!)

I think this safely establishes that the Space Shuttle has engines.The problem is FUEL. The orbiter exhausts everything it's got getting up INTO orbit, and there is nothing left for the trip down: Thus the ship is a glider all the way from orbit to touch-down on Earth. With the final bit of fuel that is left after the mission, the orbiter fires its smaller de-orbit engines to slow it down to a bit over 15,000 miles per hour (I love saying that!! SLOWING DOWN TO A BIT OVER 15,000 MILES PER HOUR) and begins its descent into the atmosphere.

Now we have to remember the cardinal rule of gliding: ALWAYS AIM LONG (PAST your landing point, not short), BECAUSE IF YOU EVER AIM SHORT YOU ARE DEAD SINCE YOU CAN NEVER MAKE UP LOST SPEED OR ALTITUDE WITH NO ENGINES. Aim LONG since you can always dissipate the extra speed and altitude with turns or speedbrakes if you wind up being too HIGH, but you are SCREWED if you come up SHORT. Following this rule, the orbiter intentionally flies its glide from orbit EXTRA HIGH TO BE ON THE SAFE SIDE.

But there is one problem: If the orbiter flies its entire approach too high, won't it glide right past Edwards? No. And here is why: For most of the re-entry, the shuttle flies with the nose WWWAAYYY up for EXTRA drag, and making steep turns to intentionally dissipate the extra energy. The nose-up attitude and steep turns are very inefficient, causing the shuttle to slow down and come down to earth in a steeper glide-angle, and if it ever looks like the orbiter might not quite be able to make it to the landing zone, they simply lower the nose to be more efficient and level it out in roll to quit flying the steep turns. The orbiter then glides better, and they can stretch the glide to Edwards for sure. The extra speed and altitude is the ace up their sleeve, but the drawback is they have to constantly bleed the energy off through steep turns (up to 70 degrees bank angle!) and drag the nose up (up to 40 degrees!) to keep from overshooting the field!!! OK, I will now walk you through the re-entry process from the beginning, as it is done in the real shuttle, and all of this carries over perfectly to the shuttle landing in X-Plane, which you will fly after reading this chapter.

After de-orbit burn, the shuttle heads for the atmosphere at 400,000 feet, 17,000 miles per hour, and 5,300 miles away from Edwards. (Yes, you are landing in the Mojave Desert and you are starting your landing approach West of Hawaii). Not a bad pattern entry, huh? In reality, the autopilot flies the entire 30-minute re-entry, and the astronauts do not take over the controls of the shuttle until the final 2 minutes of the glide. The astronauts COULD fly the entire re-entry by hand, but it is officially discouraged by NASA. The reason is obvious. These speeds and altitudes are way outside of normal human conception, so our ability to "hand-fly" these approaches is next to nil.In the history of Shuttle missions (the 100th mission has just come to a close as I write this), the real space shuttle has been hand-flown for the entire re-entry only ONCE, by an ex-marine pilot, as I understand it, who was ready for the ultimate risk and challenge.

Oh yes, did I mention you will be hand-flying the entire mission in X-Plane, a well?I have not gotten around to writing an autopilot for the Space Shuttle in X-Plane yet. I will have to do that some day, maybe after I sort my sock drawer.

Anyway, you start in X-Plane around 400,000+ feet, in space, coming down to eat air like a bag of bricks at Mach-20. Your control will be limited in space (you are operating off of small reaction jets on the Orbiter, set up as "Puffers" in Plane-Maker), but once the shuttle hits atmosphere, there will be some air for the flight controls to get a grip on and you will actually start to be able to fly the thing. You will first hit air at about 400,000 feet, but it will be so thin it will have almost no effect at all. Your airspeed indicator will read around ZERO. Kind of odd since you are actually doing over 17,000, huh? Not really. The airspeed indicator works just like the wings of the orbiter: based on HOW MUCH AIR IS HITTING IT! And in space, that is not much! It will build gradually as you descend. The odd thing is that even though you are actually SLOWING DOWN, the airspeed indicator will RISE as you descend into thicker air that puts more pressure on the airspeed indicator! You LIKE this oddity of the airspeed indicator, though, since the air is also putting more pressure on the WINGS, so the airspeed indicator is really measuring how much force the WINGS can put out for you, which is really what you are interested in!

Bottom line: THE AIRSPEED INDICATOR INDICATES YOUR TRUE AIRSPEED TIMES THE SQUARE ROOT OF THE AIR DENSITY, SO IT INDICATES LOWER IN THIN AIR, BUT THE WINGS PUT OUT LESS LIFT IN THIN AIR AS WELL, SO THE AIRSPEED INDICATOR WORKS VERY WELL TO TELL YOU HOW MUCH LIFT YOU CAN GET OUT OF THE WINGS.

A word to the wise: If the airspeed indicator is putting out MORE than about 250 knots, your wings can have plenty of lift to carry you. If the airspeed indicator is indicating LESS than about 250 knots, then the wings do not have enough air hitting them to lift you, and you are still more or less coasting in the thin upper atmosphere where the air is too thin to do much for you.

So as the airspeed indicator on the HUD gradually starts to indicate a value (as you descend into thicker air), you know it means you are starting to ease down into the atmosphere at 15,000 mph like a sunburned baby trying to ease into a boiling-hot Jacuzzi: VERY CAREFULLY AND SLOWLY. Remember, if you were going 15,000 mph in the thick air of sea level, you would break up into a million tiny pieces in a microsecond. The only reason you can survive 15,000 mph up here is the air is so thin it has almost no impact on the ship. (And again, the airspeed indicator tells you how much the air is really impacting the Orbiter. 250 is a "comfortable" amount). The trick is for you to be going a lot slower than 15,000 mph by the time you get down to the thick air of sea level. And be at Edwards Air Force Base. And that is what the re-entry is for, dissipating speed as you descend so that you are never going too fast for the thickness of the air that you are in, you only descend into the thicker air once you have lost some speed in the thinner air up higher. The whole thing is a smooth process where you never ram the ship into thick heavy air at too high a speed.

Now as you begin to feel the out tinges of the earth's atmosphere, you will notice a slight ability to fly the ship as you get some air over the wings and speed on the HUD. Now look at the picture of the orbiter on the right-hand EFIS display. The Atlantis already has this display retrofitted over it's old steam gauges (the EFISs from the Atlantis are modeled very accurately in X-Plane. Astronauts could use it for familiarization for sure). You see yourself and the path down to Edwards. Your goal is to stay on the center path. If you get above it, you are too fast or too high, you might overshoot! If you get below it, you are too slow or too low: You might not make it! (Remember ,the line is drawn with a large margin for error, so if you stay on the line, you have plenty of extra energy, getting BELOW the line a LITTLE will only tap into your speed/altitude reserve, getting BELOW the line a LOT will keep you from making it to Edwards) You must stay right near the center green line. The green line represents the desired SPEED for the early part of the re-entry, the desired TOTAL ENERGY for the middle part of the re-entry, and the ALTITUDE for the final phase of the re-entry. Don't blame me, that's the way NASA set it up. If you are too FAST OR HIGH (above the center line) then it is time to dissipate some energy: put the thing in a steep bank, pull that nose up and hang on!

The REAL orbiter will be about 40 degrees nose up, in a 70 degree bank to try to lose energy, going 14,000 mph, glowing red hot, hurtling through the upper atmosphere on autopilot leaving a 10-mile long trail of ionized gas behind it while the astronauts just watch. So how was YOUR day?

Anyway, you will do steep turns to dissipate energy as needed to keep the orbiter from going above the center green line. Look at the little blue pointer on the far left-hand side of that right-hand display. That indicates how high the nose is supposed to be. The green pointer is where the nose is now. Get that nose up. The pointers just to the right indicate the desired and current deceleration. You will not fly those, though. Look at the little pointer up top on the horizontal scale. That is the computer's estimation of how much bank angle you probably need to stay on the center green line. Follow the computer's recommendation or your own intuition for how much bank to fly, but keep that nose up for sure to keep you in the upper atmosphere and fly STEEP BANKS to dissipate the extra speed and altitude. You might be tempted to just push the nose down if you are high. Don't. You will drop down into the thick air and come to an abrupt stop from the tremendous drag, and then you will never make it to Edwards. You will wind up swimming in the Pacific somewhere around Hawaii.

Now, as you make your steep turns, you will be pulled gradually off course. Switch your turn direction from time to time to stay on course: turn left a while, then right, then back to the left again. That is what they do in the real Orbiter. You are slalom-skiing through the upper atmosphere at Mach-20. Not too shabby. Watch Edwards on your center EFIS display. You want to go there. Hit the "@" key to see yourself on a flyby. Fast enough for you? Hit the "w" key to get back in the cockpit. Caps lock off! Caps lock off! As you approach Edwards, right on your center green line on the right-hand display, you will notice there is sort of a circle or something out past Edwards. This is your Heading Alignment Cylinder, or H.A.C. You will fly PAST Edwards at about 80,000 feet or so, fly AROUND THE OUTSIDE OF THE H.A.C. like you are running around a dining-room table or something, and then after you come around you will be pointed right at Edwards. And if you are on the green line still, your altitude will be just right for landing as well. This is usually where they turn off the autopilot and hand-fly the real Shuttle.

Now you are doing about 250 or 300 knots, coming down at about 15,000 feet per minute or so... about 125 miles per hour of descent rate. Do I really need to tell you what will happen if you hit the ground with that 125 miles per hour descent rate? Do not aim for the runway or you will wind up smeared along it in a thin buttery paste. Aim for the flashing glide slope lights 2 miles SHORT of the runway that I (and NASA) have thoughtfully provided for you. If they are all red, you are too low. (oops) If they are all white, you are too high (hit your speed brakes, key "6" or use the mouse). If the lights are half red and half white, you are right on your glide slope. (about 20 degrees... airliners fly their approach at 125 knots, 3 degrees descent angle. We use 250 knots, 20 degrees descent angle... not too unusual when you consider pattern-entry started West of Hawaii, actually).

OK so you are at 250 knots, on the green line, lined up with the runway, looking at half red, half white glide slope lights with the flashing strobes by them. Hold that approach configuration until you are pretty close to the ground (3-degree glide slope to the runway), then level the descent and get your gear down. ("g"-key or mouse) Get the nose up for a flare as you approach, and touch down smoothly. Now lower the nose. Now hit the parachute and even the brakes if you want and let it roll out. Now do it 100 times in a row without a single hitch and you are as good as NASA.

PS: Special thanks to Sandy Padilla for most Shuttle re-entry information!

Flying on Mars

NASA has very exact data on the atmospheric pressure, density, and temperature on Mars. NASA has very exact data on the gravity of Mars. NASA has rough topographic maps for the entire planet of Mars, and very detailed data for some areas. The laws of physics, which are programmed into X-Plane, are exactly the same on Earth as on Mars. X-Plane needs atmospheric pressure, density, temperature, gravity, and topographic maps to deliver an engineering-accurate flight simulation. Enter a new level of flight simulation. X-Plane can simulate Mars.The following is an email sent by Austin Meyer, author of X-Plane, to the X-Plane community, at 4:35 AM, February 24, 2000:

"I DID POSSIBLY THE MOST EXCITING THING I HAVE EVER DONE TONIGHT. (OK, technically I finished it THIS MORNING). As some of you may know, I have been gathering data on Martian atmosphere, gravity, surface "texture", and topography for X-Plane from various NASA sites (http://ltpwww.gsfc.nasa.gov/tharsis/mola.html, for example) I do NOT yet have the TOPOGRAPHY for Mars, but I DO have everything else, and I have gotten it all entered into X-Plane and designed two planes to fly on Mars as well, and have been experimenting with design and flight on Mars for the last 6 hours or so. (Could I be the first human to fly a real-time flight simulation of Mars? I have seen many "movies" of "flying" over Mars terrain, but NONE have been hooked to an actual realistic FLIGHT MODEL. Has NASA done a REAL-TIME simulation of Mars flight in a PILOTED aircraft? Has ANYONE?) Well, I have for the last 6 hours, AND IT IS EXTREMELY FASCINATING.

First of all, the atmosphere is ONE PERCENT as thick on Mars as it is on earth... INDICATED airspeed is proportional the square root of the air density, so the INDICATED airspeed is ONE TENTH the true airspeed. The result? If you take off with 60 knots on the airspeed indicator, your REAL speed is SIX HUNDRED KNOTS! (about Mach 1) Take it from me, Mach-1 takeoffs are quite a thing to behold, when the plane will barely leave the runway at that speed. While there is almost no AIR for you, you do have the (sort of) advantage of only about ONE THIRD the GRAVITY, so it is three times easier to get airborne!Result? A take-off in a well-designed airplane can occur at a "mere" 400 knots or so, indicating all of 40 knots on the airspeed indicator!

Sound easy? IT ISN'T, BECAUSE WHILE YOUR GRAVITY (WEIGHT) IS ONLY ONE-THIRD OF EARTH'S, YOUR ==>INERTIAPARACHUTE? NOPE!!!! 400 mph is only 40 mph worth of drag due to the thin air. You will run off the end of the runway going 100 mph with the chute only "seeing" 10 mph: USELESS for slowing down,

->BRAKES? NOPE!!! You only have one-third gravity, so only 1/3 of your weight on the wheels. NO TRACTION!

->Reverse thrust? NOPE!!!! With only 1% atmosphere, jet or prop engines can put out basically no thrust. Just barely enough to keep the airplane in flight at mach-0.85. The jet plane needs a JATO to take off!

So how do you stop? I finally went with ARRESTING GEAR. I know of no other way to avoid blasting off the end of the runway at 200 knots with the chute uselessly deployed and brakes uselessly locked.

Speaking of which, CRASHES are interesting. No air drag to slow the tumbling planes down, and little gravity to drag them to a stop against the ground! Crashes look like "the Agony of Defeat" from the Olympics where the guy on the downhill ski-jump bites it near the top of the ramp and tumbles on and on and on, powerless to stop an accident that started hundreds of yards earlier! (though on mars, at 400 mph, your plane will tumble across the plains for MILES!)

CRUISING ALONG OVER MARS is SPECTACULAR, with the scary red-orange Martian sky, new Martian rocky-red terrain textures, VISIBLY thinner air(!) (due to modified lighting in OpenGL, modified fog in OpenGL, and visibility of stars).. you really can tell you are halfway between air and space! Returning to Earth, you feel like you are flying in soupy water! Yuk!

So what sort of planes can fly on Mars? Not anything from Earth, that's for sure. Not enough lift or thrust. A Cessna or Boeing will just sit there on the ground without even moving. Put them in the air and they drop like beveled bricks with no wings. Both of my Mars-plane concepts are much like the U-2 Spy plane (designed to operate at around 100,000 ft, in similar density air) one with a HUGE high-bypass jet engine built AROUND THE FUSELAGE, and another with a smaller rocket engine in the tail, like the X-15. The rocket plane has a lower-thrust engine, with plenty of fuel, for about 30 minutes of flight or so. The JET plane can fly for hours!

My designs are realistic (again, based on the U-2, with reduced weight for the lower structural needs (lower gravity) and modern (composite) materials). The rocket-plane is pretty much guaranteed feasible (known technology across the board), but the jet-powered one I am not sure about since Mars has so little OXYGEN in the atmosphere it may be impossible to keep a turbofan engine running. (My Mars jet-plane has twice the average fuel-consumption, though, to simulate injection of liquid oxygen or nitrous oxide). Bottom line, I now know it IS possible to build and fly a piloted plane on Mars and I now know what it would be like. (though I used a 10,000 ft runway with arresting wires... none of those on Mars now I admit)."

AND HERE IS INFO ON TOURING THE MARTIN TERRAIN, ALL OF WHICH IS AVAILABLE WITH X-PLANE NOW:

Thanks to newly-released PLANET-WIDE Mars elevation data from NASA's Mars Orbiting Laser Altimeter (or MOLA a satellite orbiting Mars that recently gathered terrain elevation data on the entire planet), we now have planet-wide elevation data for Mars. I have recently gridded all of this scenery for X-Plane, and have been flying over various parts of the planet in the Mars-Planes that come with X-Plane (download X-Plane 6.30 to fly the Mars-Planes on Mars if you have not already).

It is amazing! Is Mars flat, with a few meteor impacts here and there? NOT EVEN CLOSE!

Let me give you some examples: Even though Mars is one half the radius of Earth (one quarter the surface area) it has canyons that make our grand canyon look like a fish-pond (30,000 feet deep!). It has a volcano 65,000 feet tall. The atmosphere is gone to basically pure vacuum at 155,000 feet, so if you climb the volcano you are about halfway to SPACE! Mars has FAR MORE topographic variety than Earth, on a planet with only 1/4 the surface area. So, the sight-seeing by air is INTENSE. I have raised the max allowable visibility of X-Plane to 60 miles when on Mars so you can take in the grand vistas.Taking off and landing is interesting. You are tempted to pick a nice hi-spot to make your airport so you have no obstructions on your landing approach, but the air is so thin up there you can hardly fly! So maybe you want an airport at the bottom of a canyon or meteor crater where the air is thicker? OK, but watch out for the canyon or crater wall as you approach and depart, or impact the crater wall at the speed of sound! (The speed of sound is around the minimum speed needed to fly on Mars).

Below, see the elevation map of Mars that was generated by plotting all 64,800 ENV files that X-Plane uses for scenery on Mars. While this image was generated from actual X-Plane Mars scenery, that Mars scenery was generated from raw data from the Mars Orbiting Laser Altimeter. Look around and find your favorite place on the planet to fly, low spots provide thicker air, but you must climb out of them to go far!

This is Mars from orbit as seen in X-Plane: mars orbit sm.jpg X-Plane has a "demo area" of Mars included (just like Earth) with the rest of the planet available with your X-Plane purchase.