Problems with Challenger tracks

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Meter rat
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Problems with Challenger tracks

Post by Meter rat »

Are Challenger tank problematic? Yes. This is my experience of building mine, and what I believe causes the issues with throwing tracks. This is not based on any engineering knowledge or skill whatsoever, nor is it scientific.
The constant throwing of tracks was becoming an issue. Having read lots of threads and ideas on other sites I went through each of them one by one. This is my conclusion.

The tank is big, and has a long hull with a big wheelbase (same as the Abrams). Fitting metal tracks, wheels, idlers and sprockets adds stress to the hull. This causes the hull to flex. To get the correct tension on metal tracks, I think pulls in the adjuster and the gear box so causing the track to run out of alignment. I have never run mine with plastic tracks so cannot comment. Or the original Heng Long metal tracks it came with.

Two things seem to be common. The terrain the tank is run on and scale appearance.

One thing I did come across is a lot of is people in America, who battle their tanks, and are less bothered about scale appearance run, metal road wheels, sprockets, idlers, with plastic tracks, on hard packed dry dirt. They drive the :poop: out of them without any issues. Fit metal track and they cause a ruck of issues.

I wanted more scale appearance so opted for metal tracks with rubber pads. I also run on a more muddy, gnarly, moist terrain. My solution to the de-tracking issue was to get everything in alignment. This involved running a straight edge along the wheels and filling where required to get the road wheels in line with the sprockets and idlers. A pair of drive shaft bearings were installed, and drive sprockets were purchased with guide rings. A frame was made to stop the hull flex. This stopped the tensioner from flexing outwards and kept the hull from flexing. I also installed harder springs in wheel position 1, 5, and 6.

I don’t think this is just a problem with Heng Long Challenger. I have been in communication with a person, who is building a 1/6 scale Challenger who has the same issue with tracks.
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Herr Dr. Professor
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Re: Problems with Challenger tracks

Post by Herr Dr. Professor »

Although I have the memory of a fish who at least enjoys each refreshingly new end of the tank, I think that I recently I commented here on RCTW that hull flexing may be a greater problem with modern MBTs because of their size, especially in relation to the hull height. I also second your using a straight edge and file to get the idlers, road wheels, and sprockets, and even the return rollers aligned properly. :thumbup:

You have probably already seen the ideas of Aurelius, but they may be worth a link here because I think he has a workable solution to hull reinforcement: viewtopic.php?t=35621
Meter rat
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Re: Problems with Challenger tracks

Post by Meter rat »

Herr Dr. Professor wrote: Mon Feb 12, 2024 6:34 pm Although I have the memory of a fish who at least enjoys each refreshingly new end of the tank, I think that I recently I commented here on RCTW that hull flexing may be a greater problem with modern MBTs because of their size, especially in relation to the hull height. I also second your using a straight edge and file to get the idlers, road wheels, and sprockets, and even the return rollers aligned properly. :thumbup:

You have probably already seen the ideas of Aurelius, but they may be worth a link here because I think he has a workable solution to hull reinforcement: viewtopic.php?t=35621
Herr Dr. Prof. You did indeed comment on hull flex. It does indeed seem to be an issue. I have read Aurelius’s ideas. You could say many of the solutions I applied to the Challenger, are applicable to Abrams. And many of what Aurelius is writing about the Abrams is applicable to the Challenger.

My simple aluminium frame installed in the Challenger last year. Simply made from 25 x 25mm angle.
294C15AD-7127-4ECF-8D46-6F24D0223F2D.jpeg
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Herr Dr. Professor
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Re: Problems with Challenger tracks

Post by Herr Dr. Professor »

The photo is from Wednesday 8 November 2023 4:58 pm in your Operation Telic thread (here for anyone who wants to check the build for advice: viewtopic.php?t=32250&hilit=Telic ). You say that the reinforcing frame is 25x25mm angle. From the photo the aluminum appears to be flat stock, but I wonder if I am just not seeing the angle on either side of the hull tub with flat cross pieces. I would think that combination would do much to stiffen the frame.
zooma
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Re: Problems with Challenger tracks

Post by zooma »

Meter rat wrote: Mon Feb 12, 2024 9:48 pm
Herr Dr. Prof. You did indeed comment on hull flex. It does indeed seem to be an issue. I have read Aurelius’s ideas. You could say many of the solutions I applied to the Challenger, are applicable to Abrams. And many of what Aurelius is writing about the Abrams is applicable to the Challenger.

My simple aluminium frame installed in the Challenger last year. Simply made from 25 x 25mm angle.
294C15AD-7127-4ECF-8D46-6F24D0223F2D.jpeg
I like your solution!

Simple and effective - I am off to pick up some 25 x 25mm alloy angle !

Bob.
Never too old to learn........
Meter rat
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Re: Problems with Challenger tracks

Post by Meter rat »

zooma wrote: Tue Feb 13, 2024 9:03 am My simple aluminium frame installed in the Challenger last year. Simply made from 25 x 25mm angle.
294C15AD-7127-4ECF-8D46-6F24D0223F2D.jpeg
I like your solution!

Simple and effective - I am off to pick up some 25 x 25mm alloy angle !

Bob.
[/quote]

I’ll do some better photos for you when I’m home from work. Another simple thing for these are drive axel support bearings.
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tomhugill
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Re: Problems with Challenger tracks

Post by tomhugill »

I'll second that getting the challenger to be a reliable runner takes a bit.

On your point about metal tracks I do think you get the same issues with metal and plastic. I run a challenger with the tamiya leopard tracks which are mostly plastic but with rubber pads and several with metal tracks with rubber pads.

Now I 100% agree on alignment, but very found you have to factor in the lateral movement of.the track allowed by the fact the guide horns are a lot narrower slots in the road wheels which can allow upto 5mm movement which is enough to start throwing tracks.

Get that last road wheels nice and solid removing any lateral slop, ideally with a stronger spring and get the sprocket positioned such that the track being pulled outward to it's maximum extent isnt causing misalignment and you'll be golden!
Meter rat
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Re: Problems with Challenger tracks

Post by Meter rat »

Herr Dr. Professor wrote: Tue Feb 13, 2024 12:20 am You say that the reinforcing frame is 25x25mm angle. From the photo the aluminum appears to be flat stock, but I wonder if I am just not seeing the angle on either side of the hull tub with flat cross pieces. I would think that combination would do much to stiffen the frame.
Hopefully this makes it more clearer. The rear one is the same, but reversed.
zooma wrote: Tue Feb 13, 2024 9:03 am [quote="Meter rat" post_id=351669 time=<a href="tel:1707774539">1707774539</a> user_id=9562]

Herr Dr. Prof. You did indeed comment on hull flex. It does indeed seem to be an issue. I have read Aurelius’s ideas. You could say many of the solutions I applied to the Challenger, are applicable to Abrams. And many of what Aurelius is writing about the Abrams is applicable to the Challenger.

My simple aluminium frame installed in the Challenger last year. Simply made from 25 x 25mm angle.
294C15AD-7127-4ECF-8D46-6F24D0223F2D.jpeg
I like your solution!

Simple and effective - I am off to pick up some 25 x 25mm alloy angle !

Bob.
[/quote]

The side pieces are bonded on with my favourite adhesive JB weld. The cross braces are removable by taking out the bolts.
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Meter rat
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Re: Problems with Challenger tracks

Post by Meter rat »

I’ll itemise what I have done, to get this running as I wish. I will not be as eloquently written as some on here.

1) Ball bearing in the road wheels and idlers.
2) Rear drive shaft support bearings installed.
3) Road wheels, and idler, all in alignment with a straight edge.
4) Stiffer road springs on wheel stations 1, 5, and 6. The spring at station 5 is set on the softer of the two settings. Many do not know that a lot of models have two spring settings. A hard and a softer setting. They come on the soft setting. This helps keep the tracks under tension, when accelerating or braking. Setting all the wheels on hard, makes the model shoogle, with the wheels not following the terrain.
5) Sprockets fitted with guide rings. I may remove the inside one to see if it helps stopping the build up of muck, and dirt.
6) No play in the last wheel station. On either the wheel or the swing arm.
7) Sprockets have a washer fitted on the end of the drive shaft, between the drive shaft and sprocket. This helps with the sideward alignment when turning. I cannot remember where I read it. I am not really convinced it helps, or does any good.
8) Idlers built with 4mm nuts and bolt, supported inside by the aluminium frame. This IMHO, stops the idlers bending outwards, so helps the tensioner to do its job.
9) An internal frame, made from 25mm x 25mm x 1mm aluminium angle. This is bonded to the sides, with two removable cross braces.
10) Not strictly necessary, but it has gear boxes with bearings and faster motors for more oomph.
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tankme
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Re: Problems with Challenger tracks

Post by tankme »

Addendum to #4...drill your own hole to make it even softer or even harder.

I always try to stiffen up the first road wheel and the last on pretty much every tank except my T34s which are like the honey badgers of track retention. They don't give a crap about anything and the tracks stay on. I even had the suspension arm of the last road wheel completely back out and the track stayed on.
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