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Adding R/C to a K-4

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aceinspp

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Discussion starter · #1 ·
Well finally got it done. What ever you do, don't believe every thing you read. One of the reasons I bought the K-4 as the ad said R/C ready. Not hardly. It was quite a challenge for Paul from Southern Digital to make the conversion but he got it figured out. Looks good but may not be for every ones taste as some small holes drilled in the cab. Me I happy. I have not had a chance to run yet as I just brought it home today. Good thing I did not have to have it shipped back and forth to have the work done as Paul had a shop about 40 miles from me. Here are some pics of the install. Later RJD

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#2 ·
Hi RJ,
On the tender I see a clear hose in the center. Would that be your Water Bypass Return? I have a K4 and my bypass return is on the bottom of the tender farside of drawbar, opposite the black hose. Just curious. Having control is going to be great when running. Even though this is a 1/29 scale engine, there really is not a lot of room in the cab, so job well done.

All the best, Peter.
 
#4 ·
As far as I can tell R/C ready from Accucraft means the Lever type control arms on the Throttle and Gas valves, there is also the tube that runs from the front to the back space in the tender for the servo wires.
Granted it could be taken farther like the Roundhouse engines with servo mounts provided and servo rods also, it could easily be provided as an additional option at extra cost, I would buy it.
What RX was used in the tender and did it fit throught the narrow hatch on the rear deck of the tender?

Installing R/C in my K4 is my next project. Although I am only planning to control the throttle only.

Thanks
Steve
 
Discussion starter · #5 ·
The clear plastic line you see is for the installation that I did for the hot water bath. I can now warm the water in the tender.

Well I think it's a lame excuse for saying R/C ready. Just having a arm for throttle and fuel with holes in them, to me is pretty far fetched for being R/C ready in my book.


The RX receiver is a Spektrum AR500. More of a heavy duty type. It was installed by removing the tender shell and then building a platform for it to rest on. Also this is where the on/off switch is located and up close to the water door opening. Also the charging connection is there also.

Now that I got my work done in the yard I can hopefully try it out tomorrow. Later RJD
 
#7 ·
Jeff,
One of the nice things about 2.4 GHz receivers is that they are small with short antennas. This one is a little larger than a quarter with antennas less than 2 inches. Other Spektrum receivers are similarly small. Two of my receivers are buried inside tenders with no interferance at all.
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#8 ·
Carl,

I am pleasantly surprised to learn that 2.4GHz receivers can be used with the antenna(s) enclosed in metal.

My current use of that kind of r/c is in boats made from fiberglass, hence no metal shielding worries.

-tnx,

Jeff
 
#10 ·
Thank you for posting this! I've been puzzling over this install for quite a while. Note - In Accucraft-speak, "RC ready" means "not completely impossible to modify for RC."
 
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Discussion starter · #11 ·
Well it is not impossible to RC but I do believe the ad is a bit deceiving as far as I'm concerned. R/C ready to me is like a plug and play install. They got me once but not again. Later RJD
 
#13 ·
I do believe the ad is a bit deceiving as far as I'm concerned. R/C ready to me is like a plug and play install
There's a whole thread about what Accucraft means by 'r/c ready', that happened about the time the EBT #12 came out, which was also r/c ready.

I'm not disagreeing with you - while EBT #12's tender is definitely r/c ready - even to holes pre-drilled under the water hatch for your switches and sockets; the loco is not.

Take a look at http://www.mylargescale.com/Community/Forums/tabid/56/aff/11/aft/121521/afv/topic/Default.aspx [www dot mylargescale.com/Community/Forums/tabid/56/aff/11/aft/121521/afv/topic/Default.aspx if that link doesn't work.]
 
Discussion starter · #14 ·
Well did a test run today. Not happy so it's back to the drawing board to do some re engineering. I'm hoping to avoid adding a chain drive to the throttle servo, we shall see. Later RJD
 
#16 ·
RJ,

What would you hope to gain with chain and sprocket drive that you couldn’t provide with levers?

It looks to me like you have a linkage ratio problem; I'd guess you’re unable to rotate the needle valve adequately and or in the finite steps required thereof? By simply elongating the pushrod and re-clocking the arms you could garner more travel volume in your example. That said an ideal set-up would require different length arms (or pivot points thereof), repositioning of the arms and a new pushrod length.

Michael
 
#17 ·
The advantage of gear and chain is increased throttle rotatation over a lever. On my K-27 and K-28 I get about 270° travel on the throttle valve, whereas with a lever, I got far less. The small gear the throttle shaft has 12 teeth (K-27) 16 teeth (K-28) and the large gear on the servo has 36 teeth.
 
#18 ·
Carl,

You can garner the same results with levers, after all the gears are simply levers.

In your example the K28 36/16 nets a linkage ratio of 2.25:1. Which equates to a 1" servo arm and a .444" needle arm 1/.444 = 2.25:1.

Michael
 
#19 ·
I have looked at chain and gears as possible solutions for control and concluded that it its simpler to make and easier to adjust levers and pushrods for the desired throws needed. Coupled with a computer radio with adjustable end points and the capability to get even greater servo throws up to 150% in each direction it becomes a lot easier to make any needed adjustments.

Steve
 
#20 ·
Michael, The way I see it is that max travel on the HS-81MG, a frequently used servo, is only 40° each side of center or 80° side to side when used on the throttle terminal on the receiver. In order to get the mechanical advantage to exceed 80° travel, gears are the way to go. The Dx6i, which is the tx I use only has 125% max travel and although set to this, it doesn't really get that much, more like a little past 100% on the throttle and something less than 125% on the left/right and up/down terminals. The Dx7, which I have not used, is supposed to offer 150% max travel.
 
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aceinspp
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