PP: Hitec Servo Programming Fixture and Motor Thrust Shims

Hitec Servo Programming Fixture and Motor Thrust Shims

[bob_nj]

This is a great idea!
After reading about it, I immediately emailed Lathem and asked if there is any way
to make a similar gizmo for the giant scale 3D crowd that can be easily used if the
servos are installed in the plane.

It would have to be easily moved around on a wing for example, while being able to keep center on the output shaft.

I'm tapping my foot waiting for an answer ( dada da da, da da da Theme from Jeopardy playing in the background )

[757Driver]

I have used mine to setup two 35%'ers and I can say with out any doubt that this jig takes all the guesswork and fiddle f&^%ing around out of the equation. If you don't have one yet, you have no idea what your missing. This is by far the best complement to the Hitec 5955TG and the Hitec Servo Programmer. Totally awsome.

[bob_nj]

Can you elaborate a little on your method of setting up a wing let's say, with multiple ( 2 or more ) servos? I've always used the DOD method where you use about 55° of throw each way, but the neutral moves around as you adjust linkages and horns to eliminate binding and fighting of servos.

[ddlstang]

Bobnj ;

First thing is to program your servos. You can set whatever end points you want ( 45' or 65' ) or wahtever you like. The longer the throw on the servo the more resolution you will gain out of it also - so I like to run it up to 65'. You dont get that much more actual throw advantage after a certain point but you gain resolution. When I set up the servos I will set each set together ( ie: left wing , rt wing, rudder ). I will set the "master" servo deadband width at "1" and the other servos on that wing at "2". This allows the #2 and #3 servos to have a little more "digital" play in them so they are not fighting.

After the servos are set up set up your control surfaces. Set the control horns up evenly, I measure from the hinge line to the control horn pivot point and make them all the same. I usally just square them for general use - 1" servo arm = 1" horn, or if you are IMAC only you may want to under drive it for more resolution.

After that I install the servos, trying to make sure they are as square to the hinge line as possible. next put in the control rod and plug in the #1 servo and adjust the rod until the control surface is flush or neutral ( remember the servo center is EXACTLY 90' ). Next put in the #2 servo and adjust the rod until it stops humming, and repeat for the other servos.

Hangar 9 makes servo amp meter that you plug in which works well on finding centers and can be used in conjunction with this. So I hav'nt had to make any other adjustments after the initial set-up.

If anyone has any other inputs please respond.
Thanks
Dale Lathem

[bob_nj]

"( remember the servo center is EXACTLY 90°)"" Next put in the #2 servo and adjust the rod until it stops humming, and repeat for the other servos"Hangar 9 makes servo amp meter that you plug in which works well on finding centers"Are you saying that once you set your center, the ammeter shows no draw or fighting from center to full deflection in either direction?Sorry, but I can't keep my text from running together...

[ddlstang]

At center with no weight on the control surface there will be little or no draw on the servo ( no humming ). There will definitely be a draw of power if the servo is working at all - which just the weight of the control surface will make it work. If the servos are fighting each other you will notice that in the sound or the amp draw during deflection. You can hook up the amp meter and do a baseline on the master servo and then check the others to see how muc hof a difference there is and if they are fighting each other.

You shouldn't have any problems at all if your horns are adjusted out correctly.

[757Driver]

The really great thing about this fixture is that it garuntees perfect geometry between paired servos. A common issue when using a Futaba radio with these servos is that the end points "Shift" from where you set them with the programmer. The GREAT news is that with this degree setting fixture you can tweak the endpoints (by changing the exact point with the Hitec programmer) and then check the end result with the radio while the servo is in the fixture. ALL servos will have exactly identical throws and thus eliminating any binding between groups of servos (given the distance from the horn to hinge CL is identical).

[bob_nj]

It would be excellent if someone could figure out how to make it work with more than just the servo the modeller cuts it out for.

[JPrc]

I have one of Dale's first prototypes he sent me and it is an awesome product! It is so much quicker and more accurate than any other method I've used to program servos. I have let a few guys at the field use it and the love it! Sign me up for one when the new ones go into production. See you at some contest this year Dale.

Jonas

[ddlstang]

Thanks for the good words Jonus, I appreciated some of the feedback on these. I will have one with your name on it.

I will see you in New Iberia if your going.

[JPrc]

Definately going to New Iberia. Look forward to seeing you there. Bring me a new tray and I'll bring you some cash! What happened to your 260?