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Thread: cessna platform

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    cessna platform

    Hi, I have started to build a platform for my real Cessna 172 cockpitsection.
    totalweight including pilot approx 300-350kgs cg will be nearly zero(-/+ 7%) balanced when horizontal)at 30 cm from ground
    For now I have a platform thats made out
    2 rectangular constructions 1600x1200mm made out steeltubes 50x50x4mm
    and connected to each other with a crosslink to have bank and roll-movement(maybe in future I want to have Heave).
    I have obtained 2 liniar actuators each with the following data
    12volts 20 amp
    speed 10mm/sec stroke 300mm 2200newtonmeters.
    I can build a controll box with sufficient power for the actuators.
    I`m looking for a PLC and motorcontrollers for the above, wich doesn`t cost me an arm and a leg.
    Looking for a pricetag off around 400 euro max(800 $).
    any ideas?
    greetz Henk (Netherlands)

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    Re: cessna platform

    Hi Kermit, I am starting mine (C172) next week. Absolutely no idea on how to or what type of motors to use.
    Talking to a electrical guy who has no idea what's a flight sim. Could you PM me some pictures.
    I am trying out a pitch and roll motion initially. I also intend to make a wooden cockpit to cover the platform
    but unable to get a jig diagram of either a C152 or C172. I am only seeing pictures but no measurements as
    to exact jig.Replies appreciated.This is one of the best Sim forums where the 'family' is so helpful.
    Thanks to all.

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    Re: cessna platform

    As soon as I have found my camera , I will make some pictures.
    the best way to start is knowing how big your platform will be ,
    If you surf this site you will find all sorts of measurements(If you own a real cockpit you already know)
    during the build you can note all the weights you using or you can weigh when finished.
    To know the CG the simplest way to do so, is to put the platform on a little steel profile and shift the platform until it tumbles and finetune shifting
    until you reach a horizontal point .
    When You found the first mark then this is the place for mounting the crosslink in that direction,
    you can now find the mark for the other side left or right
    You have to be seated during the steps on shifting.
    If you make a cross with the found marks you now have the correct spot for mounting the crosslink.
    Yes its crude but its the quickest way.
    Then you need to know the forces to turn your platform.
    But you can figure them out ,if you know the above.
    Please contact me ,when you have all the date.
    I then can calculate the motors you need.
    greetz

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    Re: cessna platform

    Hi Henk,

    Before buying motor controllers and PLC, I'd think you first need to check how you will do your interfacing from FS to your controlller.
    If you are using Ian's BFF driver, there are some options, check his site. http://buggies.builtforfun.co.uk/Sim/hardware.php. I think his MD03 drivers should be able to drive your actuators.
    Note that 10mm/sec is rather slow: for 300mm it would take 30 sec from one extreme to the other. I'd say that for pitch and roll, 2~3 sec from on extreme to the other would be OK. For nice dynamic heave motion, the faster the better: My #III actuators speed is about 600mm/sec during a fast step.

    Roland
    RR

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    Re: cessna platform

    Hi Roland,
    Yes ,I was(still) thinking of Ian`s controller,
    But the motorcontrollers are asking 24 to 36 volts current, can I use 12 volts instead or do I use a 24>12 volt 20 amp converter directly after the motorcontroller.
    The speed is a bit slow , but because they are 224 kgf ,
    Your calculation is based on mounting the actuator on the outsideparimeter of the platform
    But placed nearer to the crosslinkcolum,so therefore the angle(smaller travel needed) will be greater thus faster from the(offset) point I`m sitting.
    I have to consider the lesser force it can hold/travel then,but I have more then enough force.
    and because I`m flying a Cessna not a F16 bank and roll doesn`t have to be at great speeds .
    Until I reach a desired speed I can shift the actuator around for trial and error , after wich I weld them to the contruction.

    Also I have talked to our manager, I can play with gearboxes and motors /frequentie inverters.

    I was thinking of 230volt 1,5-2 kw 1500 rpm 1ph with a MVF 63 or 86 gearbox i=100 ratio
    It will give a output speed of around 115 mm/sec at 500/550kgf (MVF 63= 350 kgf),

    If I change the i or put on a second stage gear it can go much faster but with lesser force,(speed for force), but that would be no probleem as the unit will have an overcapacity for now, I could drop more then 40 % without any problem.
    I Can/have to place the unit directly under or near the crosslink colum and then connect with a torque arm(250mm).

    But I can`t find motorcontrollers and a plc that could handle the data for now,
    I have looked for a commercial package but that would set me about 3000 euro back.

    I know you used 110 volt motors ,how did you overcome the motorcontroller data.
    Could you built something for the above motor/gearbox systeem or for the motor alone or could I use a commercial(not to expensive)unit.
    If so I could use the motor and mount a splindle actuator.

    For the future I was thinking of a springloaded or rubberised heave construction within the crosslinkcolum to have a sort of slew in the movement and not a cold up down movement.

    But first I have to sort out the bank and roll,
    Now I know why it takes time to make a reliable platform/simpit

    As said earlier I`m more a mechanical then a electrical guy.
    greetz

    Note my platform has been calculated for up to a loadweight of 1200 kilogram or about 2900lbs enough for a B737

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    Re: cessna platform

    Quote Originally Posted by kermit View Post
    But the motorcontrollers are asking 24 to 36 volts current, can I use 12 volts instead or do I use a 24>12 volt 20 amp converter directly after the motorcontroller.
    In this thread http://www.mycockpit.org/forums/show...m-construction Ian says that his motor controllers work correct with 12V input, so I think that should be OK for your actuators, provided they are permanent magnet DC motors. That would be by far the cheapest solution.

    If you are going for 230V ac motors, (that require dedicated motor controllers) you may end up with incompatible BFF data to motor controller link.

    My system uses 50V DC motors, but I run them from 36V, at which the forces are already scary enough. I use Ian's data with a home-build serial to DAC system.
    RR

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    Re: cessna platform

    Hi Roland they are indeed permanent magnet DC motors,

    I use Ian's data with a home-build serial to DAC system, well thats beyond my understanding about electronics.
    As for forces , I`m used to play around with forces up to tonnes of pulling and hoisting.
    So 500 kgf is only childsplay just kidding.
    I`m of an age that has experienced the old kick in the butt, when playing with safety during mechanical lessons at school,
    without even thinking of complaning to my parents or head of school .
    So safety to me, its like breathing air.
    I have looked on the Phidgets site but again only stuff for up to 12 volts.

    greetz

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    Re: cessna platform

    Hi Kermit,

    Sorry gents - I managed to miss this post somehow - must be the new site layout!

    Got your email Kermit.

    The MD03 motor controller will work with 12V, the problem is it is limited to 20 Amps and I doubt if 12x24=240 Watts will be big enough for what you are describing.

    You asked about the command format I use. The 40SPU-1 card communicates with the MD03's using the I2C protocol and it writes data specific to the data registers on the MD03 that control speed and direction, so I doubt if it could be used to instruct other motor controllers as it stands. However the I2C specs for the MD03's are published by the manufacturer if your controlls colleague is able to mimic its I2C setup.

    If your colleague had a particular data format in mind for his inverters I might be able to add an additional output to the card that he can read. Perhaps a simple TTL level serial output? Although this kind of mod often needs to be tested and debugged to get right.

    I have been doing some experimenting recently with a new Dimension Engineering controller - the Sabertooth 2x50 see -

    http://www.dimensionengineering.com/...ooth2x50HV.htm

    This looks quite interesting as it is a 50Amp 48V 2 channel unit with peaks up to 100Amp per channel so it should handle bigger platform loads. My hope is to add comms for it to the 40PSU-1 card but I've a bit of work to do on that yet.

    Ian

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    Re: cessna platform

    Thank you Ian
    For your quick reply, I will put your comments thru
    Please note, we are using Bonfiglioli Vectron inverters and drive units,
    Thankfully I will get it at costprice(yes I`m still a Dutchman)
    and hoping it will get my platform started.
    The only parameter I have to consider then ,
    will be our house current wich is 220 volts 50Hz 16 Amp and our house sockets can handle up to 3200watts.
    kind regards Kermit

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    Re: cessna platform

    Hi ,
    I have done some major investigation about gearing and motor,

    Decided to go with 3 dof using 24volt 900watt industrial dc motors linked with a gearbox (and prob an extra stage gearbox) with a ratio of I=35 and specialized electrics all regulated for a maxium of 18 amp per motor ,
    I know I will have less power but no burn out I hope .

    I will build the moving parts like the set up used by Roland (triangle mounted drive units) but with normal gearboxes instead of bungee cords.
    And Ian`s interface and controllers.
    I have given the actuators back to my work,and ordered several other parts.
    I also purchase a new crosscoupling with spline for Heave movement,
    Roland,please can you tell me what is the total movement height of your setup near the stabilization rod in the middle of your setup,
    I need to cut the spine to height and mount a limitswitch.
    This decision hopefully will end some sleepless nights over what to do, I know I will encounter other problems but hey, it`s a hobby
    greetz

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