KT 2019 #29

[Michael Allen]

Hi Adrian

I’ll check it later today and drop you a note

Mick

[Jerry Carducci]

It does make a considerable difference to the track position - that is to have the off set below the shaft center line. I saw the mistake on my own KT but corrected it when installing Liam's idler shafts. Unfortunately it's easy to install them incorrectly, at least the stock versions; Liam's re so much different that if you attempt the install them incorrectly you really can't. The angle set for the swing arms will influence the track tension given a fixed number of links but the distance between the idler and pannier is fixed of course so the shafts must be installed correctly.

I ran my KT in our tough local weeds here the other day and the tracks not only stayed put, both running forward and reverse
but now I have a patch where the weeds are no longer! And I usually avoid weeds or grass like the plague as they put a huge amount of stress on the running gear. I performed hard pivot as well as proportional turns in both directions so if the tracks were going to pop off that would have been the time.

I have my swing arms presently set to ~32° but that's not permanent yet. I haven't checked the ground clearance to see if I'm in the ballpark- that's my determining factor.

Jerry

[Michael Allen]

Adrian

Good to hear from you again.

I think this looks ok - what do you think?. I was getting excited then as I thought you’d cracked it!

Jerry

I can only dream of such success well done to you. I’m building this for my grandsons aged 3&6 - both of whom are tank mad and have avidly followed every stage of my build. It was a big anticlimax on Saturday when the tracks came straight off on its maiden journey - grandad is not such a hero this week!!

They will be delighted I get it sorted.

I really appreciate all the support guys


Mick

[Adrian Harris]

Sadly, that looks correct

Adrian

[Jerry Carducci]

I realize this is probably irritating, however are the right and left idler shafts both mounted the same as in this last photo? The photo showing the track near the pannier was the other side wasn’t it?

Jerry

[Michael Allen]

Jerry


All things being equal I will be able to play a little later this afternoon. I’ll check and come back to you

Many thanks for your interest.

Have you got any photos that show your sprockets after you have filed them - I’d really like to see if I have done that correctly?

Mick

[Jerry Carducci]

I'm using Liam's steel sprocket rings. I actually never filed them or changed their profile in any way.

Jerry

[Michael Allen]

Hi Jerry

Both idler shafts looked to be installed ok unfortunately.

I have refitted the tracks and ran it for a while off the ground. The left hand side tracking running sounds spot on and just the same as the Armortek tanks I watched at Tankfest last summer. This is the side that did not jump off its sprocket when running on the ground.

The other side, RHS, is a different matter however. The noise is very different , lots and lots of clacking going on and the tracking is just about taking the paint off the side of the hull.

Despite the wheels all in alignment the track appears to be circulating around 2/3mm inside where it should do in respect to both the wheels and the hull.

There is no scope of moving the wheels closer to the hull and neither would I wish to given that the track is already touching the hull, so what are the options of making the tracking move 2/3 mm away from the hull?

I have measured everything I can think of from one side to the other and see only very minimal differences - rarely more than 1 mm.

I wonder if I should swop over firstly the sprocket wheels from the LHS to the RHS and then the idler wheels to see if the problem swops sides!

Something for the weekend unless someone can see just what I am missing.

Thanks for your time

Mick

[Paul Sparkes]

Is the front sprocket correctly spaced from the hull? 21mm on mine.
Check all road wheels are in line and also the same distance from the hull side (not the 21mm) just measure it and check they are all the same.
You can also calculate the idler position from the hull to check.
Compare left and right sides.

[Michael Allen]

Hi Paul

Yep - I’ve been checking and rechecking those all week.

My front sprockets are both 20 mm from the hull.

I’ve passed a straight edge through the wheels countless times and ensured that the hubs line up perfectly (within 1mm) with each other.

I’ve compared all measurements of sprockets, wheels and idler wheels and again all ok within 1mm left hand side to right hand side.

I would like to see how others have finished their sprockets in case I have that incorrect but possibly clutching at straws I guess.

I think I will gradually swop components over from one side to the other, ie. Sprockets, idler wheels and tracks to see if the issue moves sides.

It’s a mystery that’s for sure but many thanks for your valued input


Mick

[Adrian Harris]

When you say jumping off the sprocket, is it staying in alignment with the holes in the tracks, or is it moving to one side or the other ?

Adrian.

[Michael Allen]

Adrian

When running it off the ground the tracks do not align with the gaps in the wheels by 2/3 mm. The tracks run too close to the hull and in fact scrapes paint off the side of the hull.

I experimented by temporarily pulling the sprocket 3/4mm further out from the hull and it made absolutely no difference strangely enough as the track continued to miss the gaps in the wheels by 2/3 mm on the hull side.

When running on the ground I manually lined up the track with the gaps in the wheels but the track jumped off the sprocket away from the hull almost immediately.
Mick

[Jerry Carducci]

I'd swap the tracks left to right to see if the issue follows. I'd check the gaps between the road wheels to ensure there are no tight gaps.

Although unlikely based on the consistency of these track segments I would check the links to ensure no tight tooth holes or even flash.

When running with the model raised have you noticed any tendency for the sprocket to 'hold' onto the track instead of it falling from the sprocket
as it turns?

I do/did get some track to hull scraping my self towards the middle of the track run but I believe this was more an artifact of conditions when the tracks' tension was not correct. I'll repaint that area to see if it at least diminishes. Since my model seems to be running reasonably well at the moment I'd rather not make any changes that might upset that balance..

I know having one or more sides not tracking correctly can be a real trying experience that will age even the most veteran modeler as oft times it just doesn't make sense.

Jerry

[Michael Allen]

I’ll go back to see if the sprocket is holding as you say. I never got far enough to see how the tank turns.

I cleaned, filed, primed, painted and copper greased where appropriate every part of the tracks prior to assembly and can see nothing wrong. In fact I rolled both of them up today and both behaved exactly the same as the other.

I’ll come back to you by the weekend.

Huge thanks

[Adrian Harris]

Is it just the top run of tracks which doesn't align with the wheels ?

I made a booboo refitting the tracks on my KT and managed to fit them onto the idler in the wrong place. The tracks when back on but when I tried to run it, I snapped off a couple of track horns. With the tracks on correctly, those broken horns still catch the wheels when turning. I need to replace them with some intact ones.

Adrian.