RC Radios, Transmitters, Receivers, Servos, gyros Discussion all about rc radios, transmitters, receivers, servos, etc.

kraft servos 4.8/6v torque

Reply

Old 10-11-2003, 02:29 PM
  #1  
pecojets
Senior Member
Thread Starter
 
Join Date: Jul 2002
Location: STO DGO , DOMINICAN REPUBLIC
Posts: 224
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default kraft servos 4.8/6v torque

hi !

i have a bunch of kraft servos , all working and somes are like new
the models are s-14 11 and s-15 11 . i dont remember the output torque of those servos
anybody have that info.? also any body try 6v in kraft servos.?

i have more than 40 and use it in all kind of planes , mostly in steering and trottle
i want to use ithem in a old sig 1/4 scale cub with supertigre .90 one in each surface. if they have enought torque.

pecojets
pecojets is offline  
Reply With Quote
Old 10-12-2003, 08:43 AM
  #2  
ALbert.S
Senior Member
 
Join Date: Jul 2002
Location: Roseville, MN
Posts: 263
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: kraft servos 4.8/6v torque

KPS 14ll weight 1.4oz
static torque 29oz
transit time .5sec

Kps15ll
weight 1.8oz
static torque 38.7oz
transit time .5sec
ALbert.S is offline  
Reply With Quote
Old 10-12-2003, 12:30 PM
  #3  
The PIPE
Senior Member
 
Join Date: Oct 2002
Location: Weymouth, MA
Posts: 708
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default Some tips on using Kraft servos...

Dear Pecojets:

The PIPE Here...and as I started out flying RC with a Heathkit single stick system in 1977, and STILL HAVE one or two of the KPS-14II servos that came with it, here's some TIPS I came across while using them with non-Kraft receivers...

Firstly, "ALbert.S" has the torque figures right ON THE NOSE for the Kraft 14II and 15II servos...good job remembering those figures!

The KPS-15II WAS being used in the earliest Giant Scale planes in the VERY early 1980s for aerodynamic control purposes...especially the ones that were using the earliest BIG glow engines, like the old OS .80 RC two stroke engine and the Fox .78 two strokers...and even saw widespread usage in the first Quadra Q35 and Kioritz 2.4 cu. in. gasoline burning two stroke powered models. I just do NOT know how those 15II servos, with an output torque that's even LESS than the mini sized Hitec HS-225, managed to move Giant Scale control surfaces as well as they did...but they sure DID work for the Giant Scale flyers of that time!

Also, where I first switched to Ace RC receivers in 1979 from the "flaky" Heath receivers, I ALSO found out that the Kraft servos had a VERY ANNOYING TENDENCY to "travel hard over" if you turned on the receiver first BEFORE turning on the transmitter...and COULD even do so while in "normal operation" !!! Ace RC DID have the answer to this problem...simply place an connect up a 2.2µF value capacitor in the SIGNAL line-usually an orange wire-of the Kraft servo cable, with the "positive" end (since these were usually polarized electrolytic capacitors at that time, with marked "positive" and "negative" ends) aimed towards the receiver...and the problem went away like magic!

As far as running the Kraft servos on 6.0 volts...I'm NOT too sure that would be recommended, as Kraft DID have their OWN special servo IC in their servos (NOT the "usual" Signetics NE544 chip that many other radio makers used in the early 1980s, including Ace RC)...and where the Kraft servo ICs are most likely no longer available ANYWHERE, you'd very likely blow out the chip and POSSIBLY turn the servo into junk with an application of 6 volts to power it.

Sorry to "discourage" you about the six volt usage attempt you MIGHT be wanting to do with your vintage Kraft servos....but if you'd like to run them on the "regular" 4.8 volts, and on a non-Kraft receiver, that capacitor I mentioned in the signal line will VERY NICELY make those servos behave themselves with your more modern receiver...and you should be fine!

(For your Cub, using TWO KPS-15IIs, one for each aileron, might be your best bet, if you DO plan on using them in a Giant Scale plane, just as the fans of Giant Scale did in the "big plane era's" dawning around 1980!)

Hope these tips helped!

Yours Sincerely,

The PIPE!
The PIPE is offline  
Reply With Quote
Old 10-15-2003, 07:36 PM
  #4  
smallrc
 
smallrc's Avatar
 
Join Date: Jan 2003
Location: Elkland, MO
Posts: 84
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: kraft servos 4.8/6v torque

[]

I asked Pete Waters (the PIPE's main man at KMI) about using 6v on Kraft servos.
He said do NOT! The Kraft IC won't take the extra voltage - they die! I just use
them on 4.8v and enjoy them that way.

Later... Kenny smallrc
smallrc is offline  
Reply With Quote

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service