David
New Member
Posts: 5
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Post by David on Jan 3, 2017 4:48:13 GMT
Im new to the site and have looked over several builds that were really helpful and informative, Id like to get some input on motor and gear sizing, Im planning a C172 flight build with partial cockpit and have noticed some people here are using 3/4 HP to 1.5 HP motors with 80:1 to 50:1 gear boxes, just curious if anyone has a recommendation of what would be best in my case,Ill be building a steel welded frame similar to Ga-Dawg if it can house a enclosed cockpit area (made of aluminum) Im planning to post pics along the way, I just purchased the boards from Thanos and will need tons of help from all you pros at this, I'm located in Charleston SC so Ill b working withing the power and wiring requirements of the US. Thank you in advance for any input.
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johann
Junior Member
Posts: 57
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Post by johann on Jan 3, 2017 9:32:01 GMT
Hi David, I'm also new here. And my questions are the same as your ones. There are a couple of threads who gives small answers. But at the end you don’t know what kind of equipment you really need, because it depends on so many parameters. In this case I made an excel list to calculate the torque for the motor you need, see this thread: motionsim.freeforums.net/thread/93/torque-requirement?page=3The problem is, this list seams is not ok. Thanos promised he’ll rework it when he has time. If this is done I’m sure we can calculate the right motors for our simulators. If this is done we can look for the VFD inverters. There is also a thread for it, look here: motionsim.freeforums.net/thread/9/faq-inverters-vfd?page=2Best Regards and successfulness Johann
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Post by tronicgr on Jan 3, 2017 12:27:55 GMT
I'm working on it. I found some equations that I'm adapting to the excel sheet and about to feed some motor specs to see if I get correct results
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Post by tronicgr on Jan 3, 2017 14:34:38 GMT
AC_Motor_torque_speed_calculation.xlsx (11.04 KB) OK, here it is. I calculate the max rpm of the motor as this is when the motor gives the worst case power scenario. It actually has more torque in lower rpm (but also draws more current). You can use this as template to calculate a motor size for the load you plan to place on the platform. Mind that the load is shared between the motors so a average approach would be 6 times the torque divided by three, to cover cases when only some of the motors move the load. Thanks Thanos
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Post by tronicgr on Jan 3, 2017 15:13:50 GMT
I'll add a few more calculations in that excel, like efficiency of the gearboxes and total estimate load capacity of the platform.
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Post by tronicgr on Jan 3, 2017 15:59:05 GMT
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David
New Member
Posts: 5
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Post by David on Jan 3, 2017 17:49:10 GMT
Thanks Tronicgr for the sheet,I'll be on a cpu tonight and can start laying out the loads, I've got to consider my base size also in the event I'm slinging around a cockpit so it doesn't flip over, I appreciate your input and look forward to starting the build in a couple weeks.
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johann
Junior Member
Posts: 57
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Post by johann on Jan 3, 2017 18:02:31 GMT
Hi Thanos,
thank you very much for the new list. I've some questions to columns “A”, “C” and “L”.
“A” HP stands for horse power it isn’t KW right? “C” What is constant value 5252? Where does it come from? “L” What is “kg constant” value 2.2046? Where does it come from?
The rest is clear to me and I can set in my one values.
Thanks a lot
Best Regards Johann
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Post by tronicgr on Jan 3, 2017 18:20:55 GMT
Hi Thanos, thank you very much for the new list. I've some questions to columns “A”, “C” and “L”. “A” HP stands for horse power it isn’t KW right? “C” What is constant value 5252? Where does it come from? “L” What is “kg constant” value 2.2046? Where does it come from? The rest is clear to me and I can set in my one values. Thanks a lot Best Regards Johann HP stands for horsepower. It's not KW (kilowatt) The constant 5252 is used to calculate the torque from horsepower as: T=(HP*5252)/RPM The 2.2046 constant it used to convert the Lbs to Kg: Kg=Lb/2.2046 Thanks Thanos
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johann
Junior Member
Posts: 57
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Post by johann on Jan 3, 2017 18:47:01 GMT
Hi Thanos,
now every thing is clear and I can go on. I'll swich your list to KW (kilowatt) and change the arm length inches to mm (millimeter). The rest is ok and helpfull for an european man like me.
Thanks Johann
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David
New Member
Posts: 5
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Post by David on Jan 4, 2017 0:30:10 GMT
So another quick question on this design , whats your thoughts if I have a weight of about 600 lbs on the platform me 200 lbs, frame,equipment 400 lbs, do you think Id need .75 hp, 1 hp, or 1.5 hp motors and 100:1, 80:1,or 60:1 gearbox's, figured since you all have done this Id ask. Thanos Thanks for the spreadsheet also, I understand some of it but then some is still foreign to me til I start getting deeper in this project. Should I be looking at other calculations or thinking about something else in this design that I may be missing,only asking because seems like everyone has made theirs work so far with different solutions.
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Post by tronicgr on Jan 4, 2017 2:19:35 GMT
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Post by tronicgr on Jan 4, 2017 12:13:00 GMT
So another quick question on this design , whats your thoughts if I have a weight of about 600 lbs on the platform me 200 lbs, frame,equipment 400 lbs, do you think Id need .75 hp, 1 hp, or 1.5 hp motors and 100:1, 80:1,or 60:1 gearbox's, figured since you all have done this Id ask. Thanos Thanks for the spreadsheet also, I understand some of it but then some is still foreign to me til I start getting deeper in this project. Should I be looking at other calculations or thinking about something else in this design that I may be missing,only asking because seems like everyone has made theirs work so far with different solutions. Hi David, For 600lbs load you will need 1.5HP motors with 100:1 reduction gearboxes and VFD inverters 2HP (oversized to handle inertia of load) I keep seeing new things that I need to add on the calculation sheet AC_Motor_torque_speed_calculation_updated_.xlsx (12.58 KB)
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David
New Member
Posts: 5
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Post by David on Jan 4, 2017 12:54:50 GMT
Thanks Thanos I'll now start my quest to find the motors and gearboxes. I'll take pics and videos as I go forward.
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johann
Junior Member
Posts: 57
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Post by johann on Jan 4, 2017 16:02:48 GMT
Hi Thanos and David, @ Thanos Is the last excel with all your changes (output RPM and load capacity in lbs) the last one or will you do some other ones? If so I’ll wait for your last version. If it’s completed I’ll do the changes I wrote before. Thanks @ David I’ll build my 6DOF FSX Simulator completely with aluminum profiles. It’s easy to create it and flexible at all. I’ve finished the Cockpit and also the basic platform, see pictures. I think I’ll use springs to save power at motor side. In this case look to this thread: motionsim.freeforums.net/thread/101/payload-compensation?page=2Best Regards Johann
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