# Radio control in Accucraft GS-5



## llynrice (Jan 2, 2008)

A while ago, there was a thread asking about installing RC in Accucraft's Royal Hudson. While I've not done such an installation, I recently bought a GS-5 and managed to shoehorn RC in. I hope this post will provide ideas for folks who want to do a 1:32 installation.











I used Spektrum DX6 RC with the batteries in the tender and all else in the loco cab.









It turns out that the gas tank OD is a close match to the ID of 2" plastic drain pipe; so, I used a section to make a battery mounting saddle.









I attached the receiver to the cab roof and modified the cab structure as needed to clear and mount the servos.









This view is with the back of the cab temporarily removed. I bought the sprockets and drive chain for the throttle at Servo City. The throttle on this loco turns fairly stiffly, so I used a Hitec HS-645MG high torque servo. It's big and was a bear to fit, but it has the power to work the throttle.










I hope this post will be useful for anybody contemplating making an RC installation into a 1:32 loco.


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## Pete Thornton (Jan 2, 2008)

It's big and was a bear to fit, but it has the power to work the throttle 
Llyn, 

I noted that gear ratio for your throttle. All my locos are flat out at 90 degrees, which is more-or-less 1:1 with a servo. Kevin (Mr East Broad Top) insists he needs 180 degrees but I'm not convinced it makes any difference! 

Did you figure out that you really needed to open the throttle 1 or 2 full turns to get full steam ahead? Any evidence that it is needed?


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## llynrice (Jan 2, 2008)

Hi Pete,

As it is now set up, the throttle shaft turns 180° full travel. And, I believe that it is a bit more than I need - but not excessive. The loco is new to me and I'll learn from using it what tweaks I may need to make.

Llyn


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## aceinspp (Jan 2, 2008)

Llyn Thanks for the post, handy info as I've been working on my K-4. As Pete mentioned I seem to get no more from the loco by going passed the 90 degree position. I think I have found another issue with mine that prevents the loco from performing as it should. I also thought about the chain drive. Later RJD


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## RDennis (Sep 25, 2011)

What size are those gears? I'm currently installing RC in my K4, and am trying to figure out what size sprocketed gears to get. Large size for the servo; small for the throttle seems logical. Is the throttle gear press-fit?


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## llynrice (Jan 2, 2008)

Since I last posted to this thread, I've made some changes. To go from full stop to maximum speed the throttle shaft must turn 180° Most servos are set up to rotate 90°; so, I had to use a servo gear with twice as many teeth to get full throttle shaft movement. The problem was that this halved the torque available on the throttle shaft and the loco would not come to a full stop. I had to shift the Johnson bar to neutral to ensure a full stop. I discovered that I could change to the Hitec HS-5465MG which is the digital version of the HS-645MG servo I started with. The digital servo can be reprogrammed for a different amount of travel and it has higher torque. I don't have the reprogramming tools, but learned that I could order one from Servo City which had been been reprogrammed to rotate 180° rather than the default 90° This has worked out really well. I'm using gears of nearly the same size on both the servo and throttle shaft. The torque is ample to close the throttle and I get full throttle rotation. (Please note that the actual servo rotation turned out to be a bit less than 180°, so the servo sprocket has two more teeth to get full rotation). 

To secure the sprocket to the throttle shaft, I drilled and tapped a 2-56 hole at right angles to the shaft, put in a screw and cut it off so that it projected about 1/16" I then filed a slot in the sprocket bore just wide and deep enough to fit over the projecting screw. This effectively keyed the sprocket to the shaft. 

I hope this will help you with your radio control installation.


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## weaverc (Jan 2, 2008)

Llynn,
You devised a very interesting solution to the 180° saga.

I have found that Servocity's $19 servo stretcher does the same thing to give you 180°, but adds another device to the mix. 
http://www.servocity.com/html/180o_servo_stretcher.html

I notice that you are using AA rechargeables for your receiver. I have found that I get longer usage with Energizer AAA ultimate lithium batteries, which take up less space. Radio shack has a small AAA battery holder with a built-in switch that is also useful. 
http://www.radioshack.com/product/i...Id=2062254

I also use AA lithiums in my DX6i instead of rechargeables and have found that they last a long time. No need to take a recharger and find an outlet at steamups.


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## Bob in Mich (Mar 8, 2008)

Llynn,I see in Your install,I see You removed Your Water bath Heater.When running My GS4 in the hot days I have to use it.The gas tank is so big that it gets cold fast with out warm water.


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## Pete Thornton (Jan 2, 2008)

to figure out what size sprocketed gears to get 
I use the smallest sprockets for the 1/8" chain - 16, 18, or 20 teeth. With a 20 tooth driving the 18 tooth, you get a bit better than 1:1. 


Is the throttle gear press-fit? 
On my latest version (EBT #12 - pics in this month's Steam-in-the-Garden Mag,) I used the cheapest sprockets with the 1/4" hole. The servo has the sprocket bolted to a servo arm, and the throttle shaft has a 1/4" collar (bought from the r/c shop with the servos) with a set screw and the sprocket is bolted to that. 

EBT #12 happened to have a 1/4" (6mm actually) throttle shaft. They do vary, so if you take this approach you may need some tubing to make it 1/4". 

Note also that the sprockets are available to fit the splines on the servos directly. [Only the larger/standard size servos.]


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## llynrice (Jan 2, 2008)

Carl,

The servo stretcher is a totally valid solution. Space in a 1:32 cab is limited, so I opted for the digital servo.

The batteries I'm using in the loco are rechargeable NiMh cells and I do carry chargers with me. I discovered that a Radio Shack 8 battery holder will just fit the Spektrum transmitter battery compartment and I use AA NiMh cells there, as well. So far, I don't mind plugging in to charge. NiMh cells seem to permit quite a bit of running time between charges.

Bob,

I still have in mind to use a steam water bath heater. What was installed was altogether too big to also fit the throttle servo, so I took it out. The tank in my K28 is about the same size as the GS-5 and I find that filling the bath with warm water suffices. If my GS-5 proves to be too tepid in its steaming, I'll press ahead to fit a workable steam fitting.

Llyn


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## aopagary (Jun 30, 2008)

Posted By llynrice on 07 Jun 2012 12:33 PM 
Carl,

.... Space in a 1:32 cab is limited, ...


i does look crowded in there. i don't own a butane fired boiler, but i assume there is some sort of igniter in the firebox? my biggest concern (other than the heat) with installing servos in a cab is access to the firebox door to light alcohol burners (which comprise 100% of my #1 gauge steam). can anyone with an alcohol burner/ servo packed cab comment on this? appreciate seeing all the setups i can. my R/C knowledge has risen well above the 0% i started with just from reading the comments here. thanks for sharing your setup.


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## David Leech (Dec 9, 2008)

aopagary, 
As far as I know, all gas locos are lit from the front end, either the smoke stack, or through the open smokebox door. 
I do NOT have any r/c, but I do have only alcohol fired locos. 
I light all mine from UNDER the burner, even the Accucraft Royal Hudson (which I had to modify), which has a firebox door. 
Not sure what type of burner the Accucraft Daylights have, but I am sure that you can find a way to light it from beneath somehow. 
Then you don't have to worry about passing a flame through the cab. 
All the best, 
David Leech, Delta, Canada


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## aopagary (Jun 30, 2008)

Posted By David Leech on 08 Jun 2012 04:10 PM 
aopagary, 
As far as I know, all gas locos are lit from the front end, either the smoke stack, or through the open smokebox door. 
...
All the best, 
David Leech, Delta, Canada 

re: butane... no kidding? i suppose i'll see that method some day.

for my first attempts at lighting the alcohol wicks, i did try a flame from underneath the firebox, but eventually found it much easier to crimp a small amount of wick material at the end of a piece of copper wire, dip it in alcohol, light that and then flop open the firebox door and ignite the burners through the opening. if i ever get to the point of installing R/C, i suppose i will find a way.


cheers...gary


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