Automation - Linear Actuators with pots

[B737NG]

Evening,

Hoping I can get some insight from this group. As with most projects, a lot of up front planning and research takes place. As I continue to tear down my real 737 nose section, I've been thinking a lot about automation. Specifically the throttle quad, but also the yokes.

Through my research, I've found a lot of good information about servos, motors, string pots, etc. While these have proven as very viable options, they do require a lot of work and piecing together of numerous "independent" solutions.

One area that I've read very little on in these forums is linear actuators with built in pots. To me, this seems like a very viable option, and MAY provide numerous solutions in one single unit. For example, automation (dc motor), position information (pots), and resistance (geared dc motor when off).

I must be missing something though, as I'm sure numerous folks would have thought of this earlier. What is the limitation with linear actuators? Are they immovable (locked) when the dc motor is off? Therefore are you unable to use them in "manual" mode? Any insight is appreciated.

http://www.servocity.com/html/25_lbs__thrust_linear_actuator.html

Thanks, Steve

[Nat Crea]

GDay Steve
(How are you mate? )

I too looked hard at similar servos.
From what I gathered,  without actually buying one
I note,  is that the worm gear wont allow for manual
operation. Please double check, im not 100% sure...

Nat

[N737AG]

Hello Steve


The linear actuators work great for your trim functions of the flight controls, as these do not require manual override. I actually am using them for mine. The linear actuator also works fine for the Speed Brake, if you are using the real cluth, which is underneath the cockpit's floor.


As for the autopilot inputs, they will basically not work, unless you figure out some kind of clutch. The linear actuator can not be moved by hand, but you must always be able to manually override the autopilot. At this point I have not yet built this part. I am however thinking about DC-Motors with a Polyclutch and a chain to the control's main shaft. Even though it sounds complicated, it looks like the best solution.




Axel

[B737NG]

Thanks Nat and Axel!

[B737NG]

For those interested, I finally found a linear actuator with a clutch that allows free flow operation. Not sure I'll actually use this solution, but wanted to make others aware that it is available. Thanks...

Actus 722/723 Series ERC Actuator Clutch Test

Steve

[dc8flightdeck]

Now that, is COOL!  Thank you! 

[N737AG]

Great find Steve


The absolute "great" would be if you had a control over the force of the cloth. If you use the actuator for autopilot inputs, you should always be able to override the autopilot ... in this case the actuator


Axel

[Maurice]

It seems to me there is still a basic flaw here if you are using FSX. Unless that has changed, being able to override the controls when the autopilot is on is pretty useless unless you actually disconnect the autopilot as well since the inputs from the various pots will be ignored by FSX anyway. Does XPlane behave differently?

Bottom line I think, there has to be a means to automatically disengage the autopilot when you override the controls. The basic question here is whether the autopilot re-engages automatically in a real plane after a manual override or whether the autopilot stays on all the time even during a manual override. If the latter case is true, then duplicating this behaviour in FSX is not a trivial task since FSX innards would have to be changed to allow this function.

In FSX, it's all or nothing...autopilot or manual controls. If XPlane's autopilot behaves like the A/P  in a real plane, then XP may be required as well if you really want the ability to temporarily override the autopilot by forcing the controls.

This applies as well to the autothrottle function. If the A/T is on, being able to move the TQ handles when the A/T is on is also useless if you don't disconnect the A/T as well since the inputs will be ignored anyway. This is a basic flaw in FSX and I have no idea if anybody has been able to figure out a way to modify this behaviour.

Perhaps SimA or Prosim or ? are able to allow the real A/T & A/P functionality of a real plane, in which case my reply should just be ignored. Maybe I'm still living in the past which is quite possible and even likely 

Maurice

[727737Nut]

Not if you are using PMDG737    It disconnects fine and witht he SDK out, is fully cockpit builder friendly!

[Maurice]

Not if you are using PMDG737    It disconnects fine and witht he SDK out, is fully cockpit builder friendly!

I knew I was right to quit. Sim technology is moving much faster than I can keep up with 

Maurice

[Nat Crea]

Sorry Mau, but yes with SimA, I can manually override my TQ
with A/T engaged and the thrust will do as I command until released.
Maybe you should build another 737? Imagine the fun

Nat

[Maurice]

Sorry Mau, but yes with SimA, I can manually override my TQ
with A/T engaged and the thrust will do as I command until released.
Maybe you should build another 737? Imagine the fun

Nat

Yes, I plan to do just that...in my next life

Maurice

[herculespilot]

From where we can bet this actuator?

Iam searching long time for those.

Best Regards/ Beste Grüße
Thomas

[herculespilot]

knock knock :-)

Best Regards/ Beste Grüße
Thomas

[B737NG]

http://www.actusinc.com/

[herculespilot]

Thanks a lot

Best Regards/ Beste Grüße
Thomas