Large Scale Central

Thin Servo

Electronics Live Steam
#1

I got an email newsletter from Servocity today, and the Hitec HS-7115TH Servo caught my eye. Designed for aircraft wings, it is only 0.3" wide but has more torque than the HI-65s that I’ve been using. And it includes moulded mounting lugs. Dimensions are 1.02” x 0.31” x 1.50” (26 x 8 x 38mm) http://www.servocity.com/html/hs-7115th_servo.html

#2

That’s pretty cool (and small) :slight_smile:

#3

Yeah - it looks like a good candidate for roof or side wall mounting. I’m thinking of trying one on my C-19.

#4

Don’t forget for $ 10.00 bucks more instead of 90deg you get an 180degree rotation!!!

#5
MANFRED Diel said:
Don't forget for $ 10.00 bucks more instead of 90deg you get an 180degree rotation!!!
Yes, that's the problem. $10 more than $85 for the servo !!
#6

I am a little confused as to the advantage of the digital vs analog.
Digital always costs more.

I have an HS-125 that is nearly the same thing, except it does not come with the neat cradle.
It is not installed yet so I have yet to fabricate or figure out a mount for it.

The Hitec HS-7115TH Servo has the SMALLEST spline of all the Hitec splines and has very few arms available.
Servocity call the spline their type A1
Hitec calls it a Feather Horn

Beware in the diagram I linked to below as there are TWO #34s.

In live steam I would want just about anything else but the A1/Feather Horn

http://www.hitecrcd.com/products/accessories/servo-parts-and-accessories/servo-horns-and-hardware.html

#7

I will go out on a limb and say that a digital servo will have little benefit for an R/C train. I use them all the time in my high-speed R/C aircraft where precise “centering” and consistent position is critical…For a train I’m thinking not. If you want to avoid the appearance of the control arm hanging down you could consider a linear servo, but the Hitec shown is one of the thinnest I have seen. Price is a factor but if you only need one or two it’s not that bad. My last B-25 took 17.

Slick.

#8
Don Howard said:
I am a little confused as to the advantage of the digital vs analog. Digital always costs more.

I have an HS-125 that is nearly the same thing, except it does not come with the neat cradle.
It is not installed yet so I have yet to fabricate or figure out a mount for it.

The Hitec HS-7115TH Servo has the SMALLEST spline of all the Hitec splines and has very few arms available.
Servocity call the spline their type A1
Hitec calls it a Feather Horn

Beware in the diagram I linked to below as there are TWO #34s.

In live steam I would want just about anything else but the A1/Feather Horn

http://www.hitecrcd.com/products/accessories/servo-parts-and-accessories/servo-horns-and-hardware.html


Don,

I think the ‘digital’ versions have more electronics inside so they can do things like better centering, or 180 degree operation. Not too valuable for a railroad, though the 180 degrees is nice. [Servocity sells a ‘programmer’ so you can set up the servo yourself - maybe 145 degrees this week?]

I don’t think the A1 horns are a problem. Clearly a thin servo needs a small drive spline, or it won’t be thin. The two arms that come with the servo look adequate for a reversing lever, and I use chain drive on my throttles, so a bush would be needed anyway.