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You will not believe what builders are doing!

A.C.E.S. ­ Aerial Combat Engagement Simulator featuring the JOYRIDER Project

JoyRider with CH Flightstick Pro, Throttle and Rudder Pedals Installed

If you want to experience true virtual flight then you need motion. The following how­to articles represent my efforts into perfecting the least expensive, easiest to build, most versatile motion simulator for home use.

The JoyRider is a two axis center stick flight motion simulator you can build without the use of expensive hardware. It's VERY fast, and SMOOTH and best of all it can be affordably constructed from readily available supplies with simple hand tools.

The "JOYRIDER"s design specs include;

* REAL FEEL responsiveness and balance * Maximum motion range (positive G's only for now)

* Progressive stick resistance and stability * Simple low­tech mechanical control activation

* Smooth ball­bearing suspension * Full motion range, figure "8" stick stir ­ 2 SECONDS

* 24 degrees (12+12) of pitch and roll range * Hands off stability with one finger sensitivity

* Weight range ­ fully motion tested with a 210 pound pilot * Can use a variety of display and controller options

With your favorite flight sim program loaded, the lights out under the hood, and the sound system cranked up, total immersion occurs. The stick input induced inertia fools your inner ear into thinking that you are continuing to move in the direction you started even though you really don't. Instrument pilots know the feeling. What they see on their artificial horizon is not necessarily what they feel in their head. They have to trust their instruments or risk spinning in from following possible false sensations. These same false sensations allow you to now "feel" everything from snap rolls to loops to any other flight maneuver you can think of!

How (and why) to design a flight motion simulator ­ chapters 1­4

See what our customers are building !

Complete step­by­step plans are still available!

(click pic to find out more about the plans) PDF format E­PLANS you can download at a reduced price!

Also check out the production model development site for the prebuilt aluminum "Ultimate" JoyRider:

www.flightcontrolsimulator.com

ULTIMATE JOYRIDER VIDEO

AND IF YOU DON'T WANT TO BUILD ­ SEE THEIR NEW "DREAMFLYER" PRODUCTION MODEL HERE:

http://mydreamflyer.com/

Copyright © 1997­2007 ­ Ace Sim RC ­ All Rights Reserved

HOME INTRODUCTION CHAPTERS 1­4 FAQ READY ROOM PLANS

YOU ARE HERE

HOW IT ALL STARTED

DESIGN YOUR OWN MOTION

PLATFORM

QUESTION &

ANSWERS

CUSTOMER JOYRIDER

COMPLETIONS

STEP­ BY­ STEP PLANS

The Laymens Guide To

Virtual Reality Motion Flight Simulators

Copyright © 1997 ‐ 2006 Ken Hill

CHAPTER ONE ‐ INTRODUCTION TO FLIGHT SIMULATORS

If you're a pilot, you may have used an instrument simulator during flight training. If you're a computer owner, you may have a few flight games or simulators for it. If you

watch TV you may have seen the full blown mega dollar NASA or Airline simulators that move with the yoke (or stick) input from the pilot and fully immerse one into the sense of flight or have seen or experienced rides at theme parks that move you along with the film you're watching.

Other simulators that let you experience the motion of flight include some arcade games and the new generation of location based flight simulators that allow you to dogfight against other players in a very realistic environment. These are rather expensive to enjoy even if you live near one as they charge by the minute.

Flight motion simulations are either active or passive. The active type needs servo drive motors and/or hydraulics or pneumatics to supply the motion to the "platform", (read cockpit). The passive type moves directly in response to stick motions through mechanical leverage and needs no external power. We'll deal with the passive type here as it's the least technical and least expensive to build.

To truly experience the motions and sensations of flight here's what you'll need for home use.

VISUAL ­ The more you see the better, so use the biggest monitor possible with the highest resolution or better still get a virtual reality head mounted display with head tracking.

AUDIO ­ Surround sound 3D sources and possibly transducers in the seat so you feel the thunder as you explode from that heat seeking missile.

MOTION ­ A platform you get in and ride that interacts to the stick or yoke inputs that you use to fly an aircraft.

An aircraft controls operate in 3 dimensions (six degrees of freedom) so the ultimate simulator would allow;

1) Pitch (tilt forward/backward) 2) Roll (tilt left/right) 3) Yaw (rotate left/right)

Others motions acting on an aircraft include;

4) Move vertically up/down 5) Move horizontally left/right 6) Move longitudinally forward/backward

In general, an airplane pilot doesn't directly control these last motions, but reacts to them with the first three based on throttle setting, lift, sink and turbulence. (However, new thrust vectoring jets and 'copters do allow control of these.)

If you want all 6 motions, see NASA. For a much more cost effective motion platform that you can build yourself that will allow you to fly anything from Cessnas to F­18s, we'll limit ourselves to 2 axis; Pitch and Roll. These are the most sensory convincing motions of flight and your mind will add the others based on visual cues.

COMPUTER SIMS ­ If you're already an avid computer flight sim pilot and just want to add motion to your set­up, you can skip ahead. But if you've always wanted to fly, but for whatever reason can't or if you are a pilot and want more air time and other aircraft to fly, then stay tuned.

BACKGROUND ­ The first computer flying programs were little more than a moving horizon line with a crosshair to fire your gun at the enemy. On a monochrome display it was choppy and hardly a "simulator" by any stretch of the imagination. They did give the computer 'pilot' a taste of the power of PC's for flight simulations to come. It's been said that flight simulations are the one good reason to own a personal computer.

SOFTWARE ­ Todays sim programs rival state of the art military programs of only a few years ago. Now for about $50 a pop you can fly into combat in the worlds newest and fastest fighters, buzz Manhattan in a Lear jet, battle it out over Europe in a Spitfire, or even refine your aerobatics in a Pitt Special. Best of all, all this can be obtained in most cases with near photo realistic graphics, physics modeled flight envelopes, CD quality 3D sound and with realistic aircraft controls.

COMPUTER ­ With leading edge software pushing the envelope of hardware demands, get the most powerful computer you can afford. For the current crop of hot sims, get at least a 133 Pentium with multi­speed CD ROM and 16 bit sound card. For your monitor, there is currently some good deals on 17 inchers. Some video cards allow output to your TV but resolution is limited. If you don't mind the blockyness of the picture you can sit in front of a big screen or projector TV and really immerse yourself.

INPUT DEVICES ­ Controls on the market today include everything from force feedback, realistic jet joysticks with programmable throttle/controls, rudder pedals with toe brakes, to flight yokes for you Cessna drivers. Prices range from $10 for a cheap 2 button joystick to hundreds for the top­of­the­line controllers. You may not need the best, but don't scrimp on your controls. They are you only 'physical' link with your sims and there's alot of cheap junk out there. When shopping for one, look for good feel, comfort, heft and durability. When you've got a missile aimed at your behind, you WILL abuse the controller in an attempt to avoid destruction.

ALL TOGETHER NOW ­ Don't just think you can run right out, buy the hottest computer, a truck load of sim programs, the trickest controllers, plug it all in and take off. Unfortunately, it doesn't always work that way. True, the Windows 95 OS makes hardware configurations easier, and programs designed to run on this system for the most part do set up properly. However, there are many older DOS sims that are not only very good programs, but can be found for next to nothing. These can be a real bear to get operating properly, but with patience and maybe some tech support, you'll be able to enjoy many hours of flying variety.

Another problem is simulator control consistency. For example, one manufacturer will assign the 'G' key to 'GEAR' while another may make it 'GUN'. The programmable throttles and joysticks help here as you can assign each programs functions to the same control buttons. Since most modern simulators have a steep learning curve for all the high­tech systems on board, the last thing you want to do is memorize a different set of controls for each program.

OK, you've paid your pilots dues, gone through the hoops and are ready to add the magic missing sense; MOTION.

NEXT ‐ Chapter 2 ‐ The Motion Platform

The Laymens Guide To

Virtual Reality Motion Flight Simulators Copyright © 1997 ‐ 2006 Ken Hill

CHAPTER TWO ‐ THE MOTION PLATFORM

WHY A MOTION PLATFORM

The first time you dodge some incoming triple A fire and darn near fall off your office chair, you'll see the need for a motion platform.

Once you attempt your first carrier landing in a moving platform and experience the adrenaline rush of excitement, and a load of other emotions that give you the famed "pucker factor" of real flight, you'll realize that you've now found the missing link to pure immersion flight simulation.

OK, it's big, bulky, ugly and hard to get into. But being able to fool your mind into thinking you're really doing those snap rolls makes it all worth it. After all you've always wanted your own personal 'ride' ever since you were a kid, right?

If you only want beauty, set up a static replica cockpit with blinky lights, slick decals

and such and impress your friends with your good taste. "STIMBOX"

For the real flight experience, turn out the lights, hop into a JoyRider, crank up the

volume, and let the vertigo begin. "JOYRIDER"

DESIGN CONSIDERATIONS ‐ HOW IT WORKS

Based on a balanced gimbal system along the center of gravity axis for pitch and roll, the JoyRider suspends the pilot and cockpit high enough to clear the stand, and allow enough room for the ranges of motion.

You may be saying; "Hey I already have an office chair that tilts forward and backward and have even mounted my joystick and throttle to the arms so it all moves together. It even rotates for yaw. Can't I just make it rock side to side and not have it be so big?"

Yes you can but not without lots of design problems. What you would be trying to do is put your mass OVER a pivot. This makes you want to tip over. That's why office chairs have that big spring underneath. To make this type of design you need to add a floor with heavy counterweights to balance the pilots top­heaviness. See "FLYIT"

for this type of platform, and even it has it's pivots above the base.

More weight increases mass so to have a responsive platform, one must design it as light as possible. To support the human body plus any additional hardware requires certain structural considerations. Learning from aircraft design which requires light weight and strength, one could come up with a molded composite structure, but this isn't simple or inexpensive for the homebuilder, nor can it be easily torn down to a reasonable size for transport or storage.

MATERIALS

PVC CONSTRUCTION

Our prototype is made of PVC pipe that's relativity light, cheap and available. Fittings are numerous so little custom fabrication is required. To easily make design changes, we used screws and bolts to hold it all together. A finalized design could be glued except for disassembly points and would look a little cleaner. For strength only use schedule 40 thickness tubing in large enough diameters that will support the required weight.

WOOD CONSTRUCTION

If you are a woodworker, you may wish to make your platform out of wood. We toyed with this idea but realized that to adjust the design we'd have to remake a lot of parts. Try to use box structures where possible for weight reduction, and think adjustable and expandable in your design.

METAL CONSTRUCTION

Metalworkers may choose steel or aluminum. Use thin wall tubing if steel, and choose large enough diameters that won't deflect much when you get excited and start bouncing around in the seat. A little flex adds to the excitement however!

COMPONENTS‐ Minimum Requirements

COCKPIT­ You should design it from the inside out. Start with a seat, aluminum lawn chair, go­cart, PVC yard chair, etc. Think LIGHT and WIDE! You want enough room between your legs for control stick movement range.

Figure out appropriate attach points for the seat frame side rails. The rails must support your weight from the pitch pivot points without much deflection. Remember that not only must the rails support your weight downward but also at the different angles of motion. To test material strength, place both rails between saw horses at the seat attach points and put all your weight at the estimated distance for the pitch pivot point. You can generally figure that the human body's center of gravity (CG) is about at the navel if viewed from the side. The seat frame should at least be attached to the seat in four places and have a footrest.

GIMBAL FRAME‐ The gimbal frame consists of a rectangular frame, outside of the cockpit frame that attaches to it at the pitch pivot points. It also connects to the base at the roll pivot points. Leave enough room on the inside for the bearings (see hardware below) to be attached to the outside of the cockpit.

To test your choice of materials for strength, support the ends of one of the long members on sawhorses and put all your weight in the middle. Some flex is OK since you will be dividing the load between two lengths. Remember that in reality the gimbal frame must support the entire cockpit, all its accessories like throttle, rudder pedals, display, etc. PLUS yourself.

BASE‐ Possible layouts depending on materials and tools.

To test your base design for strength, put all your weight on one end post or end panel with the base flat on the floor and unsupported. There should be no flex or

play in any direction.

HARDWARE‐ Ball bearing pivots are highly recommended but metal bushings could work if designed right. We used heavy duty caster bearings by removing the wheels and opening the forks in a vice. NOTE ‐ Only get casters that have a torsion race for

this use. Since you will be using them vertically instead of horizontally as they were designed, the extra torsion bearing race takes the twisting load you'll be applying. Do NOT even TRY the single race type. They'll wear out overnight!

The correct type to find have the normal bearings sandwiched between the mounting flange and the wheel fork bracket plus a second race between the wheel fork bracket and another plate on the wheel side of the bracket. Just look up under the wheel. If you only see a rivet, then don't get it. The type you need has what looks like a large, fat washer under the rivet that's slightly concaved. You can't see them, but the second set of bearings are in there.

The trick setup would be to attach bearing races into the gimbal and cockpit frames and use jack shaft type roller or ball bearings specifically designed for this type of loading. Much more spendy and complicated, and really not necessary as we've logged hundreds of hours on our JoyRider with the above described type of caster bearings with no noticeable wear. Just be sure to get the correct kind!

MOTION LIMITS‐ The cockpit will only be able to move side‐to‐side as far as you have room between your legs for the stick to move. Forward and back stick movement should be limited with mechanical stops on the cockpit frame to gimbal frame. Don't try to place limits on the stick as the leverage can get great enough to bend it under the right conditions.

The down stop is needed for the cockpit when it is unoccupied as most of it's weight is forward when empty. The up stop is needed so that at full aft stick, it doesn't hit the seat front (or worse if you have a really short seat!) We accomplished both needs by

putting a foam padded U shaped bar around the outside of the gimbal frame sides and connected them to the cockpit frame.

CONTROLS‐ If you are an electronics, hydraulics, and or pneumatic engineer and have access to parts, by all means consider a powered platform. Driver boards can be used to drive stepper motors or hydraulics to move the cockpit from stick inputs just like the big boys.

For our cheap and easy passive platform however, we'll simply attach one end of the center stick to the cockpit, pivot the center of the stick on the stationary base frame, and move it all around by hand from the top of the stick.

Having a nicely balanced platform is a MUST as too much self centering causes excessive stick pressure. The location of the sticks pivot point and section length can be adjusted to supply some leverage to help this condition, but the space shortage between your legs limits how much you can get.

To compensate for the sticks offset forward from the center of the pitch axis, it's necessary to allow the sticks center pivot to change location relative to stick position. Simply put, the sticks center pivot support frame that connects it to the base needs to rock up and down slightly. Hinge or bearing it to the base frame at both sides. This support needs to be as solid as possible in side to side strength.

CONTROL STICK­ Aluminum tubing is a minimum here as leverage bending loads are high. Use 7/8" .049 wall or better. Use aluminum or steel channel that fits the exterior of the tubing for fittings. You'll need one for the cockpit connection (stick bottom) and one for the center pivot (middle connection to base).

We oversized the brackets a bit to allow room for washers between the channel inside and tubing outside to prevent wear. Drill very precise holes to prevent binding and don't allow the bit to oval the holes. You want a slop free pivot that'll move freely but with no excess play in any direction. Bushings in the tubing will increase longevity as this seems to be the platforms weak link if using too thin a wall tubing.

NEXT ‐ Chapter 3 ‐ The Computer Connection

The Laymens Guide To

Virtual Reality Motion Flight Simulators Copyright © 1997 ‐ 2006 Ken Hill

CHAPTER THREE ‐ THE COMPUTER CONNECTION

COMPONENTS

The components needed to effectively integrate your JoyRider motion platform with your computer flight simulations are as follows:

Joystick Motion

Integrate joystick potentiometers with motion of cockpit to send data stream to computer.

Joystick buttons/controls

Integrate the grip of your joystick onto the control stick of the platform and extend wires to reconnect to joystick base and then on to the computer connections.

Rudder pedals

Mount off­the­shelf unit to foot rest of platform ­ extend cockpit framing for support if necessary.

Throttle

Mount to cockpit side ­ Be sure to allow maximum width between knees for stick roll movement.

CONTROL CONNECTION

To avoid confusion, we'll refer to a joystick as joystick and the control stick in the JoyRider cockpit as the control stick. Joystick base is a joystick without it's handle, and handle is the joysticks grip complete with buttons, triggers, etc. removed from the joystick. "Pot" is short for potentiometer, a volume control type electronic component inside a joysticks base that changes its electronic signal to the computer to determine joystick position. You will also hear them called variometers.

The idea for the pitch and roll controls is to have the cockpit motion move joystick pots in the same way as the stick on your standard joystick does to the pots in its joysticks base.

If you are a mechanical wiz, you could rig pots directly to mechanical linkage to a number of locations on the platform; at the bearings, at the control stick, to the seat, etc. For that matter, you could make your own rudder pedals and throttle the same way. Plans are available on our host site FINAL APPROACH (Note: Don't use the link to this site from Final Approach as it has long ago been abandoned.)

If you want to keep it simple, either find an old joystick that works good or buy a decent one just for the base. We adapted two old sticks. We used one that was shot just for the grip, and one that worked but was only a one button model with a stubby stick for the base. Don't just cut off the handle, disassemble it and keep the parts intact. Each joystick is different in construction, but generally the handle comes off in two halves. These can be carved out if needed to accept a larger post which can then fit in the control tube and be secured.

The logical place to mount the joystick base seemed at first near the control stick center where it pivots. This posed a number of problems with shortage of space, necessary linkages, etc.

We found that it was MUCH easier to mount the joystick base backward under the seat on the control stick support frame and connect it with light weight bungees or heavy elastic cord to the bottom of the seat bottom in four opposing directions. This type connection takes care of any excessive movement the cockpit does that the joystick mechanism can't follow without maxing out. It also has the advantage of compensating for the swing arc of the seat away from the stick base plane. This also reduces stick sensitivity at the extremes making for a well mannered control while still letting you get wild with the control stick. Actually, with the right tension bungee or elastic cord, you can just use two directions, side to side, with extension posts extending down from the sides of the seat. This allows up/down movement from the equal pulling of the side elastics on the stick post.

With the correct joystick base location, you can set trim, center and even a null zone by just adjusting the bungee tensions. You will need to extend the joystick base control post (if you've removed the handle). Experiment with its length to achieve full throw just before full movement of the platform. Adjust the bungees tight enough so at center all are even with just very slight tension.

WIRING

If you started with only one joystick and removed the handle, you can lengthen the wires from the buttons, triggers, etc. and run them down through the control stick tube and out the bottom. Leave extra slack for control stick movement and bundle and route them back to the joystick base under the seat. Reconnect them to the same locations they came from and you're in business. You may need to get a joystick extension cable to make it reach the computer.

If you used the handle from one stick and another joystick for the base, then another option is to wire an adaptor plug that connects to the base joystick and intercepts the control button connections and exits to a standard joystick plug. No modifications are necessary to this joystick at all except the bungee connection and hold down straps or attachments.

DISPLAYS AND SUCH

Our prototype cockpit had additional framework for a monitor and keyboard.

Monitor

Advantages ­

• Put extra old monitor to use. • Keyboard handy for systems functions, set‐ups and calibration.

Disadvantages ‐

• 30 plus pound monitor swinging around at break‐neck speeds. • Not much immersion factor from small screen. • Best with lights out.

Head Mounted Display (HMD)

Advantages ­

• VR headset is best choice for immersion. • Blocks out all outside stimulus. • 3D display with right software running. • Head tracking.

Disadvantages ‐

• Expensive. • Can't use a keyboard without lifting visor. • Low res display. • Program incompatibilities. • May need additional drivers to be loaded.

Forte makes a reasonably priced HMD that has many supported programs.

Projection

Advantages ­

• Big screen with high res display. • Can still use keyboard if needed. • Projector can be mounted above and behind pilots head to help CG problems.

Disadvantages ‐

• Expensive. • Needs large blank wall since projector moves with cockpit. • Or screen needs to be mounted on cockpit. • Needs light out. • Needs VGA to TV convertor unless using LCD computer projector then VERY

expensive.

Sony makes a lightweight TV projector that looks perfect. ATI makes video cards that have TV output (no SVGA though). It's not known how bright the projector's output is however.

NEXT : Chapter 4 ‐ Conclusion

The Laymens Guide To Virtual Reality Motion Flight

Simulators Copyright © 1997 ‐ 2006 Ken Hill

CHAPTER FOUR ‐ CONCLUSION

OK, everyone got their JoyRider flying? If not go back and get busy. The next sections are devoted to fine­tuning the platform and optimizing it for your sims.

BALANCE

Without the pilot in the seat and with all accessories installed, the cockpit ideally will balance itself neutrally at the center of the pitch range. With the pilot in the seat, balance should be unchanged. This way different weight pilots will not affect the trim of the cockpit as the pilots center of gravity is right at the cockpits CG and also at the pitch pivot point. Without counterweights at the rear of the cockpit, this becomes hard to achieve as the majority of our cockpits mass is in front of the balance point. With rudder pedals, throttle, keyboard and especially a monitor, it gets worse fast.

We elected to add bungees to hold down the rear instead of weights when we originally had a monitor mounted. This effectively helped counter balance the cockpits' nose heaviness when empty but added some pitch pressure to the pilot in flight. Without the monitor, the pitch pivot points can be located almost at the pilots CG so any weight pilot can fly without having to change the trim. We used brackets that clamped the pitch bearings to the cockpit tubes so they could be loosened and slid to different balance points easily.

FLIGHT REALISM

It's all in the program. Each flight sim handles differently. Not just different planes, but the same planes from different programmers. Some good programs allow custom modifications to joystick response, null zones, etc. This helps when fine tuning your JoyRider to fly in harmony with the visual "feel" of the planes handling characteristics. Some sims fly more like an arcade game and others like a real plane. Most of the rest of the sims are somewhere in between. One program has so little control damping that it causes so much overcontrol that it's nearly impossible to fly in the 'Rider. Lag time can also be a problem, but these sims are rare. The only time the screen shouldn't match what the 'Rider is doing is during a stall or spin and then as in real life, once you regain control of the craft, everything's back to normal. Of course, in a loop or roll, the screen will continue in the direction the platform is moving but won't match again until you cancel the maneuver.

CALIBRATION

To calibrate the cockpit, just think of it as another joystick. Be sure you are relaxed and centered in the pitch and roll range, and the joystick in the base is centered as well. It may be hard to see it, so get a helper to look for the first time. Be sure it's trims are centered as well, since you won't be able to reach them in flight. Next just follow the "move stick to ***** and click button" instructions in the program and you're set.

FLIGHT

Most pilots go crazy the first time in the cockpit. They overcontrol, complaining that it won't react as fast as they are used to. Actually, once you get used to it and stop trying to slam the stick like you unrealistically did on your desktop joystick, you'll settle in and relax and find that suddenly you're really just starting to learn to fly. Let's face it, could you physically really pull those 10+G turns in that F­16? You won't pull any down Gs in the JoyRider, but you will experience pitch and roll inertia loads and you'll have to adapt.

ALTERNATE CONTROL METHOD

Besides the control method described in the last chapter, we also tried another option you should know about. There are a couple of wireless joysticks on the market that can be attached to the control stick directly so that no other connections need to be made! If you happen to have one of these sticks, by all means use it. The catch is that the control range of the wireless stick may be limited by the motion range of the control stick. The up side is that they (at least the VIR­1 model we have) allows response programming. This lets you increase the joysticks response to max out sooner so the limited range is minimized. It takes some tweaking and fiddling, but it

does work. These digital controllers seem too unfeeling for my taste, but hey, give it a try!

CONCLUSION

Just as in the general aircraft market as pilots became designers in the home­built movement, sim pilots can also hand craft their "flying" machine. This way they can balance the flight characteristics they prefer and not be forced to fly a platform that is too expensive or something that someone else thinks is the best design. You've seen some of the store bought models available from the picture links in the other pages. We don't say we have the best design. It's sure not the best looking, but so far it's the least expensive we've found, works well, and is adaptable to multiple configurations.

AVAILABLE NOW ‐ COMPLETE STEP‐BY‐STEP PLANS