forwards/backwards RC

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invicta280
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forwards/backwards RC

Post by invicta280 » Sun Apr 26, 2020 12:30 pm

Morning all. I had a rare chance to steam up my 'Owain' yesterday. As usual she steamed up ok and was quite happy to gallop along towing a single carriage but would barely move in reverse. It seemed as if it wasn't getting enough steam in reverse. In fact it felt as if the reverser had adjusted itself so that the central position on the R/C controller was no longer the 'neutral' setting.
Previously she has been quite happy to run in either direction.
Is it possible that the reverser needs adjusting? Not sure how to go about that.
The Owain is a Swift Sixteen body on an Accucraft Ragleth chassis/boiler.
I have taken videos of her in action but since the demise of Photobucket I have no idea how to load videos on to a forum. Here's a rather poor picture of her trundling along the Cobtree Line yesterday.
Thanks for any advice anyone can give.
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tom_tom_go
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Re: forwards/backwards RC

Post by tom_tom_go » Sun Apr 26, 2020 1:12 pm

You can use YouTube to upload videos.

What R/C system are you using?

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Re: forwards/backwards RC

Post by invicta280 » Sun Apr 26, 2020 2:20 pm

Hi Tom
Thanks for your quick response. I'm not so quick off the mark, having just got back from queueing to get into the Co-op !
Yes, I used to have a youtube a/c. Think I'd better try to resurrect it.
My R/C is a Planet T5 2.4GHz. I know very little about R/C. 16mm trains are my first experience in this area.


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Re: forwards/backwards RC

Post by tom_tom_go » Sun Apr 26, 2020 2:40 pm

Have you flipped the switch on the upper right of the controller by mistake? Try it in both positions.

What about the trims, possibly adjusted them slightly?

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Re: forwards/backwards RC

Post by invicta280 » Sun Apr 26, 2020 3:33 pm

Yes, I played around with the adjustment trims ? ( just below joy sticks) but didn't seem to make much difference.
In my ignorance I thought the flip switch in the top corner was for changing channel.
I think I used my standard trouble shooting method of fiddling with everything to see what happens. Luckily I don't work in a nuclear power station!
It could be a mechanical issue in that there is something causing drag or inertia in reverse which might be too much for the loco to overcome.

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Re: forwards/backwards RC

Post by tom_tom_go » Sun Apr 26, 2020 3:49 pm

Disconnect the reverser from the servo and see if it works.

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Chris Cairns
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Re: forwards/backwards RC

Post by Chris Cairns » Sun Apr 26, 2020 5:06 pm

If you need it, Planet T5 manual available here - https://www.manualslib.com/manual/929200/Planet-T5.html

Planet T5 Transmitter.jpg

Switch on top of transmitter is for Channel 5, so will not affect your reverser channel. The manual trims on the T5 transmitter are notorious for being inadvertenty moved - the trim for your reverser is only slightly off centre here.

It is not unknown for the reverser control to go out of adjustment on these Accucraft locos. Luckily the piston valves used have a scribed setting ring to add timing.

Forward Gear.JPG

With your reverser set to fully forward your piston valve reverser should look like this above (this is a Caradoc). When you place the reverser to full reverse the scribed ring should be flush with the edge of the valve block (I've placed the scribed ring just off the valve block here so you can the scribed ring).

Reverse Gear.JPG

If the scribed ring is not flush with the face of the valve block in full reverse, then the reverser timing is out & will need adjusting, but that will depend on your R/C installation. You could be lucky in that it just needs the reverser trim adjusted on the transmitter, otherwise it may need the reverser lever mounting moved (has elongated holes under the screws) or the valve will need screwing in or out on its threaded stud with lock nuts.

A photo of your piston valve reverser & scribed ring in full reverse will help diagnosis.

Chris Cairns

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Re: forwards/backwards RC

Post by invicta280 » Sun Apr 26, 2020 6:24 pm

Ok chaps, I'm learning here. Hopefully tomorrow or Tuesday I will get a chance to check this out. The loco was working slowly (just) in reverse but wouldn't travel around a curve and would stop if there was even an imperceptable gradient.
In forward mode it romped away.
Nothing seemed amiss in the cab and the reversing lever as controlled by the servo seemed to be business as usual. I will check and report back. Thanks again for kind assistance.

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Re: forwards/backwards RC

Post by invicta280 » Fri May 01, 2020 10:05 am

Well, it took a couple of days to get another chance to look at 'Owain'. I've been so busy during 'lockdown' that I wonder how I normally had time to go to work.
Anyway, looking at the greasy side of the loco (and it surely is embarrasingly greasy under there!) I took some photos.
I took them outside with a phone camera in dubious light conditions so I can only hope that they are clear enough.
It looks like the scribed line is not close enough to the valve block in the Reverse mode.
At the end closest to the cab there is a small nut on the threaded end of the rod. Is this adjustment for the reversing mech?
FORWARD
Image
REVERSE
Image
I've got a feeling someone is going to tell me to get at the underside of this loco with a rag and some isopropyl alcohol ! :D

'
'

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Re: forwards/backwards RC

Post by Soar Valley Light » Wed May 06, 2020 8:52 pm

The day before Chris's explanation about valve setting I noticed that my Ragleth was creeping froward when supposedly in mid gear. It made for some beautifully slow speed running but it clearly wasn't right. I couldn't believe it when I saw Chris's explanation. I've checked and the valve setting is out exactly as he described. I think I've reset it but haven't had chance to give it a try yet.

It was a fiddly job due to the small size of the nuts and the podgy size of my fingers! What size are those nuts anyway?

Thanks for the advice Chris, et al. This is a shining example of this forum at it's mutually supporting self.

Andrew
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"'cause I can't manage on three gaffer!"

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Chris Cairns
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Re: forwards/backwards RC

Post by Chris Cairns » Sat May 09, 2020 5:05 pm

Sorry for the delay Nigel / Andrew - I do not get notification emails & usually view the Forum without logging in so missed your postings.

Nigel, your photo does indeed show that the reverser is out of timing. The scribed line should be flush with the valve block face whilst in reverse so needs to be further in. Two ways to correct this, either

1. Move the reverser lever quadrant backwards. As you have radio control fitted that is going to work against us here so you would need to disconnect the servo linkage first. The reverser quadrant base has two elongated holes which allow for this fine adjustment, and is secured by hex head bolts or cross head screws.

Reverser.JPG

Ideally if you have a spare M2 bolt or screw (if not use one of the mounting bolts/screws temporarily) use this to hold the reverser lever in the reverse position. Loosen the mounting bolts/screws and slide the quadrant backwards until the scribed line is flush with the valve face. Tighten the mounting bolts/screws. You will now need to adjust the servo linkage or reposition the servo horn so that the R/C is now holding this new reverse position (hold your transmitter control to reverse whilst doing this). Once adjusted you can remove the M2 bolt or screw from the reverser lever.

2. If there is not enough adjustment by moving the reverser quadrant, then you will need to move the piston on its threaded stud. Slacken the M2 locknut at the back of the piston reverser valve and rotate the piston clockwise to screw it into the required position. Tighten the M2 locknut.

Hopefully job done.

Chris Cairns
Last edited by Chris Cairns on Sat May 09, 2020 5:58 pm, edited 2 times in total.

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Re: forwards/backwards RC

Post by tom_tom_go » Sat May 09, 2020 5:45 pm


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Re: forwards/backwards RC

Post by Chris Cairns » Sat May 09, 2020 6:04 pm

Thanks Tom.

I purposely do not do email notifications.

Was not aware the image limit was only 500 KB, have now posted an image that works.

Chris Cairns

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