Clutches are in

[jackpilot]

Picked them up today at USPS
They look real good. The flange to which each lever will be attached is one solid nice piece of aluminum, mounted on six pins and fitted with a roller bearing.
Axle is 5/8 , flange is 2"diam, torque adj up to 12 pounds.
Happy camper

[Boeing Skunk Works]

Cool stuff! I can't wait to see them installed.

[jackpilot]

Me 2

[Trevor Hale]

Ok Guys,

I am no mechanical engineer, this is why I couldn't build my own throttle, because I need to have the feel behind the throttle.  I gather these clutches will allow you to "Feel" Some resistance in the levers, but my questions are...

#1. The clutch allows the servo to move the throttle lever, but also allows you to interrupt the movement by holding the throttle in one place without damaging anything?  Is this correct? 

#2. Will you be doing this Jack?

#3. How big would these clutches be?

#4. I like the drawing, it shows me how it is attached to the levers, but I guess I don't understand how it works. Would the rod that goes through "Both" levers be split to allow independent movement, or is it one solid rod? and if so, how does one clutch not interfere with the other for independent movement of the levers?

Just looking for an understanding here..  If anyone has the patience to show me LOL.

Trev

[jackpilot]

OK
First of all' I could not figure it out either until David C. Allen enlightened me on the subject..

1) these clutches could be used for a motorized unit and solve the problem of taking over the servos. I'm not going that way as it is not a 737TQ and I am not a great fan of automated flight. I use them as a "brake" for friction, not as a clutch. In other words I start moving them at the point where they slip, and that point is selectable up to 12 lbs/inch on this model.
2) these are 2" outside diam and 1"3/4 thick on a 5/8 axle. They appear a tad bigger than life size if you click on their pic.
3) The axle is fix, does not turn, the cartridge is "screwed" to it and does not rotate either.
The lever is attached to the housing and the friction plate and this assembly (housing, friction plate and lever) can rotate if the slippage torque is reached, as it is not linked to the axle.
In other words , on the drawing the right part of the axle that goes through the housing and lever could well be eliminated and has the sole purpose of making the lever more rigid laterally To that effect the housing has a roller bearing which allows it to turn "freely" on the axle as soon as the slipping torque ( hand effort) is reached.

Actually it is very simple when you hold the darn thing in your hand....

[Trevor Hale]

Thanks Jack,  that really clearly explains it.  Sounds like neat little devices.

[Aerosim Solutions]

Hi gang,
I just had to put in my two cent's worth because I believe really good throttle friction can be achieved in a much simpler way. When I produce TQs I have all the levers together on an axle with the spacers etc and this gives me a measurement for the spacing of the outer plates or chassis. In this pic of my A340 design, you can see the grey 'cotton reel' spacers at the ends of the sideplates. They are the same length as the levers held together so they fit snug in the chassis but they don't yet have any friction. The solution is fitting two long bolts through the casing, one plate is tapped and these bolts screw into these tapped holes. The bolts squeeze the casing slightly and the friction achieved is totally adjustable, it works brilliantly Lock nuts on the outside prevent the friction bolts from coming undone. These bolts are dual use, they are also the travel stops for the lever movement.



No offence Jack but I think my two quarter bolts would be cheaper than your metal clutches! I don't want to deter you from using them but a simple solution is available for this requirement and it isn't always that obvious to all!

Cheers, Gwyn

[Pegger]

As with Jack, I am not a big fan of fully automated flight. Auto-throttle is a function I never use, so servo slip won't be an issue in my TQ. (PS...love the sqeezebox idea Gwyn!) But the idea got me to thinking. Does the clutch have a return-to-center feature? If the servo continues to drive the trottle pot round and round, and then you grab the handles and restrict the movement, would that not put your throttle levers out of position, and thus possibly lead to a situation where the max and min power positions no longer coincide with the electrical input being put out by the potentiometer? This situation could cost you a sucsessful landing.

Sorry if my question seem noobish, but my focus will be on learning the electrical input and programming aspect until I am comfortable enough to put iron to solder, an my curiosity is peaked at the moment.

[Trevor Hale]

Thats a good question, I would like to hear the others answers regarding this as well.  I would think that your potentiometers would be attached to the levers themselves.  so they would never be out of synch.  the position of the servo's though would be, although I am sure when the throttle was brought back to idol the servo position would reset. 

Looking forward to hear how this could be corrected.

Trev

[Bob Reed]

As with Jack, I am not a big fan of fully automated flight. Auto-throttle is a function I never use, so servo slip won't be an issue in my TQ. (PS...love the sqeezebox idea Gwyn!) But the idea got me to thinking. Does the clutch have a return-to-center feature? If the servo continues to drive the trottle pot round and round, and then you grab the handles and restrict the movement, would that not put your throttle levers out of position, and thus possibly lead to a situation where the max and min power positions no longer coincide with the electrical input being put out by the potentiometer? This situation could cost you a sucsessful landing.

Sorry if my question seem noobish, but my focus will be on learning the electrical input and programming aspect until I am comfortable enough to put iron to solder, an my curiosity is peaked at the moment.

The answer is no. The pots are actually driven off the throttle arms at least in mine. So stop the arms from moving and you stop the pots. Throttles stay in sync.  AT may be calling for more throttle but if the throttle is not moving, it is not getting it.

[Trevor Hale]

I also gather that if you used 360 degree servo's that would also solve the "Servo issue" just my tidbit.

[jackpilot]

Hi Gwyn,
You are right, I am probably making it more complicated than needed.
But the secret of your system is the very shape of the lower part of your levers ? right?
A big fat disk, as far as I remember.
I tried that on a small prototype in aluminum, but  because I do not have the right tooling to make it good, the friction of the alu plates was not linear at all.
Putting a plastic washer in between helped a bit but after a while friction needed to be readjusted  again and again.
On the present TQ, I am working with 3/8 alu bars, to shape it like yours I would have to work from a 3/8 thick aluminum plate and cut it properly (hence the magic of the CNC which I do not have).
The clutches offer a very smooth friction feeling,  when you move the lever it feels like their is something big at the end, probably because there is an initial very very minute backlash for the clutch to engage. It is just a feeling, hard to put into words.

Your TQs are pro work and must be a joy to use  for sure, and your system is bulletproof and simple. I basically do everything by hand, and constantly run into roadblocks doing it. But it is fun.

For those interested in using clutches for an autothrottle, give credit to the original  builder:
http://www.737flightsim.com/AutoThrottle/AutoThrottle.html
http://www.737flightsim.com/AutoThrottle/ClutchBrake.html
http://www.737flightsim.com/AutoThrottle/200TQInstall.html   

The best part of the fun is that we learn constantly from each other and manage to create very nice gizmos.
TBC...

[Maurice]

I also gather that if you used 360 degree servo's that would also solve the "Servo issue" just my tidbit.

Any servo can be made into a 360 degree servo, but that is not really necessary in a TQ.

Maurice

[Maurice]

From my understanding of a real TQ operation, if the pilot tries to move the throttle when in AT mode, the AT would automatically disconnect and the throttle would revert to manual mode only (I could be wrong). At any rate, the main attraction for me for having servo motors was so that the throttle handles would be approximately where they are supposed to be when disconnecting the AT function.

By that I mean if you are on short final and still on AT and you disconnect the AT, but the throttle handles are still in the cruise position, then there would be an immediate surge of power. That’s not a huge problem but it is much nicer to have the handles where they are supposed to be at any time.

As far as clutching is concerned, the real  limitation for most simple setups like mine is how much power can the servos produce to overcome the static friction and that could easily be achieved with a setup like Gwinn’s. The real attraction of a mechanical clutch would be if the friction could be reduced or eliminated when in AT mode and increased at other times and that means some sort of electrical control of the clutch with an electro magnet or something like that.

Bottom line I think is that it is very easy to overcomplicate things. Nobody here is building a CAE simulator as far a I can see and compromises have to be made somewhere depending on what you want to achieve.

Maurice

[jackpilot]

By that I mean if you are on short final and still on AT and you disconnect the AT, but the throttle handles are still in the cruise position, then there would be an immediate surge of power. That’s not a huge problem but it is much nicer to have the handles where they are supposed to be at any time.

Maurice

On FS when you disconnect the AT, the power stays at the same level as long as you do not touch the throttle.Whatever their position which gives you time (if avail) to look at the N1 and be ready to move the trottle at approx the right position, usually around 50% on a stabilized approach. Not realistic but manageable.
Not CAE like. U are right!!lol

[jackpilot]

Gwyn is right, it is probably an overkill, but...Boy, does it look good!
Two independent levers on the same axle.

[Trevor Hale]

Man that does look sharp.  Holy crap

[when acting as a wave]

BEAUTIFUL!

[Boeing Skunk Works]

That's a great job and they look good installed. Very pro looking.

[jackpilot]

Thank you guys.

[Maurice]

After much thought & observation, I have to say this looks definitely more professional & beautiful than nylon washers and a bolt

Maurice

[Trevor Hale]

Nobody would ever argue that Mau.  (Jack will be conducting the class as soon as he is finished) LOL.  Think he is taking us all to school.

Trev

[jackpilot]

Not sure about that!!!
The darn thing is still far from its "Simworthiness" ticket!!  lol

[scorpioflyer]

Jack

You really have to let me know if you are still planning on coming to Montreal........

Antonio

[jackpilot]

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