TQ - Motor mounting options

[srisim]

For mounting thrust lever motors, I see these two (see attachments) options as popular among many here. 

In comparision, Option #1 is taking up less space horizontally, but needs extra right angle drive component. Also, in option #1, there is no additional bearing support at the sprocket end.

I am leaning towards option #1 due to its' compact nature. However, I am concerned with:

a) extra right angle drive (extra point of failure?)
b) lack of support at the sprocket end (any stability issues?)

Which one do you prefer/recommend?

Also, appreciate if someone please tell me the model/part #s for items marked as A1 (right angle drive) and A2 (sprocket) in Option #1 and where to purchase?

Thanks
Srini

P.S. To illustrate my question, I am re-using the photos posted earlier on this forum without prior permission from their original owners. Nick/Flying_Fox and Fred/FredK, hope that is ok and thank you.

[mickc]

Just a note before my reply, there are a lot of different ways to "skin a cat" as they say, and people have various ideas and build methods that work well for them.  My build was based on what I wanted to achieve, and the design I chose was based on my engineering experience.  my preferences are not in any way implying that other ideas or methods are inferior 


I use something similar to the second option, but with the motors overlapping to save space.  This way the ends of the motors to not go outside the outline of the TQ frame.

The motors and end support bearings are mounted on 3mm Aluminium brackets, and everything is bolted to a steel plate.
The brass shaft that goes through the end support bearing mounts inside the clutch and butts up against the motor shaft. 
Clutches are Polyclutch 16 plate, 6mm bore models, with the drive sprocket machines and pressed onto the outer case.

I would say the end support is essential in this configuration, as the clutches can flex quite a bit when the cables/chains are tightened.

The only slight downside with this option is that there is some inherent backlash in the gearboxes of these style of motors, which leads to a few mm of free play back at the handles (although the real aircraft also has a small amount of free play).

The right angled motors would likely have less backlash as they are a simple worm drive, not multiple spur gears.
Although the motors in option 1 have no end support, these clutches could be self supporting, as the motor shaft is quite thick compared to the Option 2 ones.

Also my pedestal is quite packed inside (build progress photo included below), and i have limited room available, so this method works great for me. 

In my opinion you don't need an overly large motor to drive the throttles.  They only have to provide a slightly higher torque than the slip clutch is set to.   I have measure the throttle handle tension in the real NG with a tension scale, and they need roughly 1.5kg of force to move.  I have this replicated in my setup and even these small motors only run at a 20% duty cycle during full clutch slip.

[FredK]

Srini -

I have a surplus pair of the exact motors in option "A".  Model is Crouzet #82048029.  They are rated at 42rpm running @ 24v, 21rpm @ 12v, and 10rpm @ 6v.  The right angle drive is integral with the motor.  You do not need to purchase that separately.

These are heavy duty motors (they weigh over 2 lbs. each) and the shaft assembly is very sturdy.  You would not need the shaft bearing support for this design.

However there is actually more shaft "free playback" with these than the motors in Option "B".

If you want to go in this direction or to experiment with you can have them for $25 each plus shipping.

But based on my experience with both of these motor types you do not need anything this heavy...the smaller 12v robotics motors work perfectly fine.  You could couple those with a separate right angle gear drive (readily available at Servo City etc.) if you wanted to go in the direction of a more compact footprint design.  I would venture you would need to have the bearing pillow support for the shaft though.

Fred

[Flying_Fox]

P.S. To illustrate my question, I am re-using the photos posted earlier on this forum without prior permission from their original owners. Nick/Flying_Fox and Fred/FredK, hope that is ok and thank you.

Hi srini,

No problem whatsoever!

A1
42-rpm @ 24VDC, 7 ft/lbs torque. Running at 12 V.   
Crouzet reversible high torque gearhead motor.
http://www.wisconsinpartsdatabase.com/INDIANA/Electrical-Components/Remove/New/Without-Warranty/Crouzet-reversible-high-torque-gearhead-motor.pl

A2
http://www.dynatect.com/mechanical-motion-control/slip-clutches/mechanical/slipper-clutch
SAS20 or SAO20 as far as I know.

Not sure where it's better to buy now, since it was 4 years ago and Rob aka 727737Nut was installing them.

Nick

[srisim]

All - Thank you so much for your detailed, helpful explanations..


MICK

I am quite inspired by your top-notch build quality. Wish I had the same skills/resources. I like how you solved the space issue and fitted both motors inside the frame.  I notice both you and Fred made the same observations about the motor rating/size. I am not sure what your motors are, but I am thinking of start experimenting with a 6 RPM motor that Fred suggested in this thread and copy your mounting solution (with your permission  ). I have already grabbed two of these 6 mm bore polyclutches on ebay.

I too realized early that in the option #2 design, extra 8mm to 6mm coupler can be eliminated by using sprocket with the same bore dia as motor (6mm) on the other end.

Could you share specs/source for your SPROCKET and the SPROCKET END BEARING please?

Btw, those simstacks boards and connectors arrangement looks like beautiful lego construction

FRED

Fred, thanks for the offer of the motors, much appreciate. However, based on your earlier recommendation, I am thinking of starting with the 6 RPM servocity motor (part #638210) unless you advise me otherwise. And will try avoid introducing extra right angle drive (as well as the 8mm/6mm coupler) if I could.

NICK

Thanks for the part details and your forgiveness for using your pic 

For A2, it wasn't' the slip clutch, I already bought the clutch. I was asking about the details of the SPROCKET attached to the right of the poly clutch. 


P.S. Here is the (work in progress) google docs file that I am putting together with all the info I am gathering for others benefit.

[mickc]

MICK

I am quite inspired by your top-notch build quality. Wish I had the same skills/resources. I like how you solved the space issue and fitted both motors inside the frame.  I notice both you and Fred made the same observations about the motor rating/size. I am not sure what your motors are, but I am thinking of start experimenting with a 6 RPM motor that Fred suggested in this thread and copy your mounting solution (with your permission  ). I have already grabbed two of these 6 mm bore polyclutches on ebay.

I too realized early that in the option #2 design, extra 8mm to 6mm coupler can be eliminated by using sprocket with the same bore dia as motor (6mm) on the other end.

Could you share specs/source for your SPROCKET and the SPROCKET END BEARING please?

Hi Srini,

Sorry i just caught the reply to this.

I use 5 rpm motors with a 19 tooth size 06B chain plate sprocket, and the same Polyclutches as you have purchased.
The plate sprocket bore is machined out to be slightly smaller than the stepped down hub at the end of the clutch.

The sprocket & clutch hub are shrink fitted together :-

The clutch hub is then removed from the clutch and frozen for a few hours, and the sprocket is heated up in a small sandwich oven.

The hub is then pressed into the bore of the sprocket with a wooded drift, and both are left to return to room temp.

The sprocket shrinks and the hub expands as they cool/warm up which locks the 2 together as a single unit.

The end of the clutch hub is drilled out to 6mm.

Doing it this way saves a lot of space and allows the motors to be closer together.


Support bearings are just generic single roller bearings with a 6mm inside diameter and a 20mm outside diameter. 
These sit in machined housings and have a 6mm brass rod through them into the clutch hub.   Stop collars are clamped either side of the bearing to prevent axial movement.

The housings pictured were 3D printed, but i ended up machining some out of aluminium instead.
Also there is a pic attached of the bearing and shaft without the clutch /sprocket installed.

[kurt-olsson]

I am still searching and hope to find a low rpm engine with clutch built in, that would be the best. But i havent found any.