DC motors source?

[matta757]

Hey,

Anyone have a source for DC motors? I tried Servo-City but their DC motors cannot turn unless they are being powered to do so, so they really wouldn't work for my autothrottle since I couldn't move the thrust levers by hand without ruining the motors. Anyone know of any good suppliers? I prefer a motor with 10 rpm or so if possible, since I have already done the math and bought the gears!

Thanks,

Matt

[Hessel Oosten]

Matt,
Isn't that the reason people use slip-clutches on the axis of their motors ?
In that case manual moving IS possible.
Hessel

[Joe Lavery]

I'm happy for someone to correct me here but doesn't the autothrottle disengage when you move the levers by hand in a real aircraft?

Joe.

[Bob Reed]

Yes.... Pilot always overrides the AT....

[fordgt40]

Joe

Suggest you view the demo video of the Revolution powered throttle. Apparantly a lot more goes on like the throttles returning to the commanded position after manual intervention and other things happening if both throttles are out of phase by a certain amount. Probably depends on the mode, but worth watching the video. Perhaps mleavy737 could help here?

David

[MLeavy737]

Hey guys, just be clear the autothrottles dont really disengage in a sence that the switch is turned off and the autothrottle system is now out of the picture. With the autothrottle system turned on from the MCP the pilot is always able to override the system meaning you can just move them where you want them however as soon as let go of the throttles they will return to autothrottle mode.

Quick example.. On climbout and leveling at 10000 ft. Unless you change the FMC speed restriction to something else it will have a 250 kt speed restriction below 10000.  Now when approaching levrl off at 10000 ft the airplane will not accelerate until 10000 or above and not 1 ft below that. In order to make a smooth transition and level off at 10000 while the power starts to come back sometime about 9600 ft well hold the power up and override the autothrottles so the airplane continues to accelerate during the last few hundred ft until level off. Basically this makes it smoother for the passengers as now the airplane will not have to make a power reduction followed by an acceleration. But like i said before, the autothrottles will not disengage. They are still on.. Switch up and green light on

My suggestion. Use slip clutches..

Mike Leavy

[Joe Lavery]

Thanks Mike, I guessed you would know the answer, now I'll have to redesign the whole thing   

Cheers
Joe,

[MLeavy737]

Thats what makes it fun Joe redesigning and rebuilding!

The next fun step with using dc motors and slip clutches is the software to drive them its one thing using servos but a whole different story going the dc motor route.

Ill be attempting to tackle that problem shortly. There may already be solutions online somewhere but i havnt really looked too much yet. Let me know if you find anything.

Mike Leavy

[fordgt40]

Joe/Mike

I am on the same track, but converting a Symulatory throttle from crappy servos and mechanics to a dc motor version with slip clutches. Having changed the "poor" spur gears I am about to test the arrangement of toothed belt drive pulleys and high torque low rev dc motors. I will keep you posted.

David

[Joe Lavery]

Guys I've just bought an Open Cockpits DC Motor Card and already have a couple of DC motors I bought on Ebay. So now I'm dragging myself through the tortuous learning curve of mastering SIOC.  Although to be fair many of the forum members have provided links and sample code to get me started.

Nico Kaan's site is a mine of information which is just as well because I find the SIOC manual quite heavy going. The fact that it's written in a slightly offbeat flavour of English doesn't help either. I'll quickly add that I fully appreciate that the author's first language is Spanish, so what's needed is for someone who understands SIOC to write a step by step guide for idiots, (like me) 

However I'm persevering and as Ian so eloquently put it, I've asked the wife to remove all sharp objects from the kitchen. 

Cheers
Joe.

[Joe Lavery]

Jack, I see you've used slip clutches on your new (all Aluminium) throttle, would you please tell me what type they are and where you bought them?

Thanks

Joe.

[jackpilot]

http://www.polyclutch.com/polyclutch/mechanical-slip-clutches/

[matta757]

Hey guys,

Well, this slip-clutch thing is new to me, so please excuse my questions if they are silly or off-base.

Jack- is there any chance you could snap a pic of your slip-clutches attached to your throttles? I just want to get an idea of how you have it set up. I am assuming you use a chain to move the gears on the throttles? Also, which of the three slip-clutches from that website are you using?

Regards,
Matt

[Joe Lavery]

Thanks Jack, as usual a great source of information. 

Cheers

Joe

[jackpilot]

Thanks Joe

Matt:
http://www.cockpitbuilders.com/community/index.php?topic=302.0

http://www.cockpitbuilders.com/community/index.php?topic=589.0

http://www.737flightsim.com/FlapBrake/FlapBrake.html
http://www.737flightsim.com/AutoThrottle/ClutchBrake.html

[matta757]

Jack,

Can you give me a ballpark on what one of those slip clutches you used costs? You have to request a quote on that site...

Thanks,

Matt

[jackpilot]

Mine were $110 a pop.
Call them they will help the selection.
You have to figure out the torque you need, those things are adjustable, the more you screw the barrel, the tighter the torque.
Choose one with multi disks and tell them exactly what the end use is.
My rep there was Matt Ripinsky, very helpful.
JP

[Hessel Oosten]

Matt,

See e.g. www.conrad.de
search number 184121, price less then 10 euro

Hessel

[jackpilot]

Sorry
Nothing to compare with.
That clutch is a mini thing with very limited braking.

[Hessel Oosten]

Jack,

It wasn't my intension to compare with ...., that would be strange ...: 10 euro against $ 110.

In a fully working A/T I've seen this slip-clutch (3Nm, 30 Ncm) working to * full satisfaction *.

The force we need to only slip over the DC motor axis is VERY limited.
We do not need to override the power of the motor.

On the Opencockpits site there are also designs of home made (and working) slip clutches.

Hessel

[matta757]

Jack,

What's the benefit of having the multi disks?

Also, I don't intend to put them on an axis with the throttles (like I think you did) since the throttles are already on an axis using a standard 1/4-inch bolt. So would it be possible for me to take one of these clutches, attach the DC motor to it, attach the plastic gear to the other end, and then set it up so that the gear on the clutch contacts the gear on the throttle lever? I like the idea of using the torque to create the tension necessary to make the throttle push feel more realistic, you said this is adjustable? I'm just trying to decide if I want to spend $200+ for this...

Hessel,

Thanks for the tip, the price certainly catches my eye!

Regards,

Matt

[jackpilot]

Matt you should try the Conrad stuff, at that price hard to goof!
More disks make the connection  tighter  (no Backlash)

I see your point Hessel, but what I mean is that a throttle quad has to be heavy duty , even overbuilt .
For two reasons, one because like the rudders it is heavily used and takes a serious beating, and second because anything lightly built will feel light and irrealistic and will get  loose after a while.

I would not contemplate Plastic or nylon gear (bound to need dentistry !!) or mount anything on a 6mm axle.
You will be better off using  sprocket gears and chains
Check David Allen site :
http://www.737flightsim.com/AutoThrottle/ClutchBrake.html
JP

[Hessel Oosten]

As seen somewhere on the OpenCockpits site.
Don't remember the exact link.
Home made clutches.
See pics.

Hessel

[jackpilot]

Matt

Was just checking my files about the Polyclutch.
1) I was wrong with the multidisk, just go for the single disk with 6 pins.
2) Go for a slipper clutch . Can be with the shaft going through or not depending on your design.
3) I am not versed into motorized TQ operation but from what I have seen it may happen that you have to override the motor action , (hence a strong assembly and no plastic gearing). I may be wrong though. Mike L. wrote something about that recently, Doublecheck.
4) the Polyclutch are not inexpensive but they are industrial grade. Here is the ref for the one I used.

"Housing made from a carbon steel (12L14), with an oillite bearing pressed in
The clutch design is a thru-shaft design with a bore of 5/8", low backlash which is 6 holes in the plates and 6 pins on the housing. With up to 13 lbs of torque and  low backlash the new part number is PAO32-10HUL "

The 5/8 shaft and the bearings mean that there is absolutely no lateral play in the assembly. All parts are tightly working together with a rock solid feel.

Hope it can help.
Designing a TQ, and "worse" a motorized one is no small challenge . Keep us posted with your work!!

Hope it helps

[matta757]

Jack,

Thank you for the continued advice. I just returned from a vacation to Seattle, so I will start taking a look at what I want to do and keep you posted.


Matt