RichardMac

I have three Kraft servos model S45-II which are slightly larger than a regular servo and a Kraft servo marked only with the words "CARBON WIPER." Can anyone give me any information on these servos? Year they came out? Are these reliable servos? etc. Thanks.

Art ARRO

My Feedback: (5)

I was a long term Kraft R/C user, from late 1960s-1990s, and do not recall any servos made by Kraft with the S45-II designation.I usedKraft- made servos from their KPS-9 to the KPS-33 but nothinglabled S45-II.Kraft did begin offering servos with carbon button pot wipers in the mid-80's and many of their servos could be upgraded with this mod. Also, note that Kraft offered a Sport Series radio that may have included S45-II servos but I have no direct knowledge on this.
For their standard 3-wire servos, I have updated the plugs, adjusted the neutral to a 1.5 ms pulsewidth and used them extensively in sport models with good results- all driven by JR equipment.
Perhaps some old timers can add to this response.

Art ARRO

RichardMac

The three S45-II Kraft servos came with a gold metal-cased signature series receiver model KPR-7D series seventy-nine which I acquired on the internet.

warbird72

My Feedback: (79)

I have the Kraft radio system here with the KPR7Kb 7ch rx. The servos are theKPS26KB X 4 works like a top! But one servo may have a striped gear.. But comes with wall charger and instructions.. The system is the KP4KB!!

ronwc

My Feedback: (404)

I too used Kraft equipment for many years, and still fly a 79 series single stick. Are you sure your servos don't say S-15 on them. Either way, I always thought the Kraft servos were not the best, when they jittered the pots needed cleaning, which was a little too frequently.

warbird72

My Feedback: (79)

I'm real sure they say what I typed. I had them right I front of me when I posted it..

sidgates

My Feedback: (2)

I bought just about every servo Kraft ever made and offered them on the Royal Radios that I built from 1969 to 1983 and I don't remember any called S-45II. What color are they? Can you supply a photo? They had KPS-9, KPS-12, KPS-14, KPS-15 and KPS-16 and some had the added "II" designation.

Rob2160

My Kraft Series 80 with KPS 20 H Servos gave me 20 years of perfect service..

Not familiar with the S45-II model.. It must be a later model servo because they were definately not around in 79. 80 or 81... (I'm nerdy enough to still remember the servo specs of the day...)

How things change in 30 years!

[youtube]http://www.youtube.com/watch?v=s8DU7WD8ra0[/youtube]

jrlingrel

I never used Kraft, but did use a lot of Heath servos, starting with KPS-9s. These were copies of KRAFT and were extremely good (I still have about 20 of them. The nice thing ab out them is that they used a variable capacitor for a feedback element instead of a pot. These also had both a rotory output and a liner rack (very nice feature). Then as Kraft introduced newer and smaller servos (KPS-10s, KPS11s and KPS12s. I think they went to a 3 wire system with the KPS10s. These were all very good servos. I am in the process of restoring a Heath system and will install it in a KWIK FLI next fall. Should make a very nice nostalgia airplane. Anyone who needs any old Heath stuff, PM me as I have boxes and boxes of stuff.



John

RichardMac

Apologies fellows, upon closer examination, the three Kraft servos I have are S15-II and NOT S45-II. Are the S15-II servos good enough quality to fly with today, or do they need some tweaking? Any idea when they were manufactured.......Thanks for you comments guys....

Art ARRO

My Feedback: (5)

The Kraft KPS-15 II servois a very good analog servo suitable for sport model aircraft. I recommend changing the servo lead to whatever you are currently using- JR, HiTec, Futaba, etc.
The neutral pulsewidth of these servos is 1.4 ms and the standard neutral for most current R/C systems is 1.5 ms. This can be adjusted with sub-trim or you can open the servo and adjust the pot until the output arm is at a center neutral position. The pot is retained by 2 small screws and it can be adjusted by just loosening the screws and rotating the pot- a couple of degrees. If your uncomfortable doing this you can have an R/C tech perform this-along with the servo lead change. I had a local R/C tech service perform this on about a dozen Kraft servos for a small fee. Radio South may handle this but it is best to contact them for a quote. Good luck on this.

Art ARRO

woodie

While the Kraft KPS-15 II was a 'good' servo in it's day and can probably handle a sport plane, by the time you replace the connectors and reset the centers, etc, you will have spent at least half of what it would cost to buy a new standard servo with the right connector and that new servo from a good supplier will be faster, stronger and more reliable than the Kraft servo. Personally, I wouldn't spend any time matching them up with a current radio.

Don't get me wrong, I used plenty of Kraft servos in the past and they served me well, but technology moved on and for the most part the technology just got better. We were discussing this specific topic at the field a few days ago. No one felt the older servos were 'better' and were even joking about 'no way would I go back' to those type servos.

On the other hand, a collector out there might be very happy to get their hands on some nice KPS-15 II servos to complete a set......

Woodie

TFF

If you are going to fly a kraft radio use them; if you are going to use them with another radio go replace them. Why, If you not in to nostalgia a modern servo will be better. I love my Kraft radios I still have 5 that are legal narrow band, but the servos are slow and if the pots are worn or dirty they twitch. I fly a Kraft with my Ugly Stick and building a Kwik Fli for another and have a Super Fli kit for another; my form of fun. I believe they are about 38 oz of torque. They are tough, and anything bigger than a 60 size plane they will be weak.

Art ARRO

My Feedback: (5)

RichardMac,
Well you've received some feedback on your older Kraft servos and you can decide what is best for your requirements. Personally, I believe that the Kraft KPS-15 II with a carbon button wiper is a fine servo for sport R/Capplications. The torque is about 38 oz/in with a 0.25 sec transit time. The reliability is probably a lot better than many of the low-end foreign import servos currently available. Back in the day, I used Kraft KPS-14 II and KPS-15II in Formula I/FAI pylon racers and ducted fan scale models. Just today I flew an F-20 sport jet with KPS-14s in the throttle and rudder position and they worked well. This propjet is powered by a Jett SJ-46 engine and does about 130+ MPH-radar clocked. So if your application is for sport models less than .90 CID the KPS-15 II would befine. They are also quite rugged for nose gear steeringor throttle positions on just about any R/C model aircraft. It's up to you.

Art ARRO

Art ARRO

My Feedback: (5)

Another point on using these older Kraft servos is that many of them were made with reverse output- before reversing functions became standard in the transmitter. The reverse servoscan be identified by a small dimple on the top or bottom of the mounting tabs.A pair of KPS-15 IIs, one standard-1 reverse, would be excellent for flaps on a typical 60-90size warbird. A standardY-harness would connect these to the flap channel port of your receiver.

Art ARRO

RichardMac

I plan on using the S15-IIs with a Kraft 5c transmitter series 79 and a signature series 79 gold metal cased dual conversion AM receiver. Would the CARBON WIPER servo be alright for an aileron servo? I would like to use this radio set up for .40 and .60 size sport aircraft.

Art ARRO

My Feedback: (5)

The KPS-15 II would work just fine for your application. The carbon pot wiper delays the jittering that eventually comes with the older metal arm wipers. On your older Kraft Signature AM system, I'd ensure that it is "gold-stickered" to the 1991 specs. As I recall the Signature Series were pretty good and easily met this requirement. However, I'd still have it checked overby Radio South or a similar R/C tech service.

Note that I still fly a Kraft Spectrum Series radio on AM even at crowded events such as the NEAT Fair with several hundred other pilots and radios operating and no problems whatsoever. Good luck with this "vintage" radio-nice to see it put to use.

Art ARRO