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Guest Ferdie

Video of cockpit motion prototype

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Looks like a nice start....The only thing I noticed was that the model seemed to bank and pitch the same amount as the plane in the screen shot. Are you just feeding the actual aircraft attitude to the platform? If so, that will feel wrong. The angle of bank on the sim platform should be not the aircraft angle of bank, but the perceived angle of bank. This is easy to obtain, though - the bubble in a traditional turn and slip shows perceived bank.Perceived angle of pitch is trickier as it's a combination of actual pitch angle and acceleration - in other words, as you accelerate down the runway you need to pitch up the platform to simulate the g-force pressing the pilot back into his seat, even though the actual pitch angle remains zero.Richard

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Yes. I know.This is only a example of IOCards and SIOC.With some lines of SIOC you can easy to program a mixed movement of 3 servo-motors and can move your cockpits in 2'5 axes.If you want simulate g-force you need to apply your algorithms.

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How are you thinking of moving the platform once you move to full size? Can you get big enough servos, or are you thinking of rams with servos operating the switches?Richard

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Very interesting indeed.But i think this is not suitable for a cockpit: you need to produce the impression of the forces, by simply moving the cabin like the real one does, you won't achieve this result.Strangely enough, there is practically no material about this matter: reproduction of accelerations in a fixed environment.Maybe you can have a go at google.

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Well, I thought there was an offset in FSUIPC that details the X-Y-Z accelerations? If that is so, then it would be simple enough to use those offsets to control instead of actual bank, pitch and movement. Anyone thought of offsets being the key?

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Get axes is easy... Only need to process information of pith and bank.But apply G-force algorythm if very complex.Rafael Carmona send me this information from NASA and a good simulations of sense not is easy.We have technology for mechanical and electronical systems for this cockpit motion, but complete simulation software need a large study.

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I have flown both a military two-axis simulator (Just bank and pitch)and a commercial full motion simulator and I can tell you the difference between even the 2-axis and a fixed platform is night and day.A full 6DoF is even better of course, but the difference between a 2-axis and a full motion is actually far less than between a fixed and a 2-axis. It's also far, far easier to simulate. As I mentioned above, the perceived bank is already given to us in MSFS - it's simply the ball angle in the turn and slip - and the perceived pitch requires only a simple trig calculation using aircraft acceleration and downwards g to give the perceived bank. (I'll look in FSUIPC - maybe it's even already there)Additionally, both of those axes are held to maintain the correct feeling, unlike heave or yaw which require some system to washout the movements without the pilot being aware of it.Richard

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Anyone thought about implementing a motion platform in their home-pit?I have thought about it as a possible step 2 option (whenever everything else is done :-)But i've probably will restrict it ti 1-degree of freedom, acceleration and redardation that is... engine thrust will tilt the cockpit backwards and retardation as of flaps, gear drag, reversers and brakes will tilt the cockpit forwards.This is, as i think of it, the most affordable and most "immersion-gaining" configuration.I will accomplish this by mounting the pit on a robust frame with an axle athe the center of gravity, preferrably at the position of the pilot, with a hydraulic piston to actuate the tilt.Picture of my thoughts:http://forums.avsim.net/user_files/97155.jpgStep 1 is the full cockpit in place.Step 2 is the same cockpit mounted on a frame (3) lifted by the two axles on each side of the cockpit. (2) is the hydraulics that drives the piston (pink) to tilt the cockpit back and forth...Hehe, ill tell you how it goes.... in a few years...What i'd lite to say, or take up to discussion:Is it worth, for a home pit to make a more complicated solution to get the tilt axle just to tilt you a little when you do a bad turn? A correct turn with rudder compensation for aileron brake effect will not cause any forces to the sides. But the accel and retardation of the airplane is a very common thing, and is really felt by all onboard.WHat do you think?/ Olle

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FYI -- ALL of the BELOW is rambling and thinking out loud --- like sketching on a napkin in bar after 4 drinks of conversation lubricant.:-)Yes indeed, a kewl topic to discuss.I have been thinking along the lines of a small turbo prop trainer that is replacing the Tweet. The energy required will be a lot less then those of you who would try pitching and rolling a 737 cockpit.I will not use an oil system. Just to much chance of making a BIG mess that will never clean-up. Plus chance of fire and having a hole drill through you.Air is probably too soft for the needed response rate to simulate the jerk and g loading. Heave ho! knock your head again the canopy. How about electric servos, I was in a 3 dof NASCAR stock car siimulator recently and it was powered by servo motors. It was able to roll and pitch +/- 25 degrees and "heave" about 18 inches. Itr would also sneak back to a neutral position to allow for the next force clue. The Stockcar mass problably was close to what I would be thinking of for my project. Big motors/big controllers, big peak electrical power demand, and big bucks. Too big for me.Back to a safe, cost effective, responsive system. How about water? High pressure pumps are now available in high pressure washers. They don't have the needed displacement, but that is what accumulators and pressure tanks solve. Run the system for several minutes before t/o, accumulate energy, and then emulate. Use a high pressure tank and accumulator, but regulate the pressure to 100 to 200 psi to the displacment cylinders and control valves. Could possibly use lawn sprinkler control valves at this lower pressure. 150 psi for sure.With a closed loop we probably would have to put in a heat exchanger to keep from boiling the water on long flights. But, if we bleed water down the drain, and made up water with cool tap water, maybe a heat exchanger would not be need.I don't think one needs to simulate the full loading, just enough to trick the mind into thinking something is going on. Having been there before, and having expectations, the mind will fill in the needed details.FYI -- ALL of the above is rambling and thinking out loud --- like sketching on a napkin in bar after 4 drinks of conversation lubricant.:-)Regards,BobShttp://s95171098.onlinehome.us/junk/aopa.jpgSeems the rage to talk about the "size and speed" of each others computer. Beat this if you can for solving novel/unique problem anywhere in the cosmos. ..Have K&E and know how to use it!

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I love that video. There are multiple people who have tried these motion platforms. I think (IMHO) that the most workable ones for us simmers are those which use something like high-torque DC motors. An example can be found here http://www.inmotionsimulation.com/2DOF.htmlThese motors can be combined with a feedback variable resistor to create a servo (this is my understanding of what a servo is). Another example can be found herehttp://www.simw.com/index.cfm?fuseaction=d...etails&pid=1299I especially like the idea of paired pillow blocks (the bearing surfaces for the platform.) Finally the idea of washout and preception. This is definately "code"-able...maybe even in a larger type PIC...I would have to read the thesis (some good bed time reading!) I guess the mose expensive pieces are the motors.- Mike

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