track snapping problem

[Paul Wills]

Hello Chaps,

I need help with a track snapping problem. I bought Antony Rowley's Panther knowing it had a problem with snapping tracks, but when I have tried to resolve the problem I can only find two solutions, and they are to remove the bump stops, or lower them below the wheels. The set up has not been changed from when it was built, apart from the fact that Antony only ever ran the Panthers tracks tight and I have loosened them. As you can see from the following photos, the bump stops have been catching the track when it is at what I would call the correct tension, which results in the Panther lurching to one side then, ping, the track snaps.

Has anyone else had this problem, if so how did you reslove it





Thanks Paul.

[Kent Wiik]

Hi Paul,

Interesting!
Is your Panther in the photos jacked up or just sitting on its tracks by its weight?
Notice it has no turret but still she ride far too high compared with the real thing.
I doubt the turrets weight will do much difference.





Do you know to what angle the suspension is set?
The whole bump stops must be below the wheels or the track will clash into them.
So was the real thing made and so has the model to be done as well or the snapping tracks will occur.
Just my 10 cents.

Kind regards
Kent

[Marcel de Groene]

Hello Paul

I suffered the same problem. I lowered the bump stops and cleared anything that could jam the tracks. First I believed that a surface like dry grass put to much strain on the tracks. I had my tracks broke on two occasions, dry grass while turning and the same in snow also during turning. On the second occasion I blamed the cold. After clearing anything that could jam the tracks and being very careful while turning it didn't occur anymore but I still drive very carefully, especially when turning and to be honest that makes driving less fun. Track tension could be another solution. While on real Panthers the track rests at the third road wheel I remember Lee Sellars saying that you need to tension the tracks real firm and not being realistic like the real thing. I don't know if you have the old or the new suspension system which could matter.

[Paul Wills]

Hello Kent & Marcel,

Thanks for the reply's. My Panther is sat under it's own weigh, and you are right it does not go down any more with the turret on and it has the standard suspension.

I am going to lower the suspension and lower the bump stops, then we will see what happens, it can only be an improvement. I can't do anything today because my son has borrowed my tool box to fix some young ladies car , I hope she is worth is because I am going to kill him when he gets back . So I will let you know what the angel is when I get my Allen keys back.

Kent, I have finished a short biography on Major Heinrich Schmeerman, an Artillery office I have been researching. just follow this link and you can download his Bio from this page http://www.paulstiger1.co.uk/Hauptmann- ... ection.htm Let me know what you think, I have really struggled to find the information on him, it doesn't help that the Koln main archive burnt down a few years ago.

Thanks Paul.

[Fabrice Le Roux]

Hi,

Interested to learn of this problem as I have yet to start on my Panther G (first series) and Universal/Bergepanther builds. On the the Gustav I am considering fitting internal shock absorbers as per original to the appropriate axles. The original fullsize design needed to dampen the suspension to prevent dynamic oscillation from propagating leading to porpoising. Indeed the Tiger, slower but heavier, has internal shocks too for the same reason. The Sherman VHSS did not but the later HVSS models did.

From what you have shown and described it does appear to be a track to hull fouling issue but I am curious to learn if anyone's tracks have failed due to transitory snatch loads, where the model has bounced and recoiled off a hard surface, rather than in a turning manoever.

Track failure was and remains the bugbear of all armoured units, so fixing the blasted things can be viewed as an "authenic" benefit of owning and running our models!
many thanks for the feedback.
cheers
Fabrice

[Paul Wills]

Hello Fabrice,

It seems a long time since we last spoke, I am not sure if I thanked you for my piece of cake last year (Thanks again).

I notice on both occasions that the time the Panther would snap a track was when it was climbing over something, it always happened when the front and rear suspension was not being compressed and the centre was. I say this but, Antony had problems when he was turning.

Regards, Paul.

[Antony Rowley]

Hi Paul,

The snapping of the tracks was improved when Paul M fixed the idler housing with nuts & bolts. There was still a little movement within the housing so depending on the terrain and the pressure on the idlers they could still move a little. I also noticed from time to time when driving off the pallet the Panther was housed on that the right hand track would stick and I would have to reverse then drive forward to free it. I think lowering the suspension might help too. I'm sure you'll get it sorted once you get your tool box back. Let us know how you get on.

Thanks Ant

[Fabrice Le Roux]

Hi Paul,
Hope your cake wasn't too soggy this year...it was the siren song of the cake that lured you the tea tent after all

Leaving the cases where the track can be shown, through witness marks, to have fouled the hull fittings, I am curious to explore the dynamic situations that could explain track failure. Did the tracks fail passing above the roadwheels or when between the sprocket and first road wheel or between the last roadwheel and idler?

Tank designers refer to "catenation", a term borrowed from molecular biology, to describe the way tracks behave and interact with the running gear. Obviously the track is fixed in relation to the sprocket, while the idler acts as an equalising pully, hence the upper returning track is free to flap about. When the suspension is in compression the slack in the track gathers under its own weight (in full size vehicles) on the return side. When the suspension decompresses the slack is effectively pulled back around the idler. As this is always against the dynamic tension of the rotating sprocket, the transitory shock loads can be quite severe. This can be made worse by the relativey small diameter of the idler, so that the tangential loads through the track castings lead to failure. This might have been partly why the larger idler was adopted from Oct 1944 (plus better cleaning characteristics). The tracks on real Panthers seem to have been pretty reliable, the roadwheel tires being more prone to failure. Moreover an unacceptable "pitch resonance" discovered by Prof Lehr in the prototypes led to shock absorbers being fitted to all production series Panthers.

Fitting shock absorbers to the second and seventh suspension arms (internally!) might mitigate the shock loads and increase track life...alternatively drive slower.

This is quite an arcane subject, but it is always interesting to see how real-world solutions can be applied to scaled down, but just as real, problems!

cheers, Fabrice

[Tim Bowman]

Hi Paul

"snapping" tracks aside, I love the look of your Panther and its paint/weathering. Close up looks real!

all the best
Tim

[Paul Wills]

Hi Fabrice,

I think it may have been both the cake and the siren that lured me to the tea tent not sure if you remember, but you gave me some advice on how to create a gif, did you see the results

Tim,

Yes I know what you mean, I thought the same thing when I saw the photos. Although she is heavily weathered, what you see there is real rust, which reminds me, I need to do something about that, real dried on mud, diesel that had dripped from the tracks and general ware.

Paul.

[simon_manning]

hi paul, a small observation i have made on the panther bump stops and where they are mounted seems very critical, the tracks are close to the hull plus the movement over rough ground brings the two parts together, on building mine this became apparant, the real bump stops have a more sculptured profile, does this help to some degree?, i have noticed mine rubbing aswell due to track tension and terrain conditions but not snapping rideing over the smoother profile, but i do not drive mine a great deal, i hope this is of some use, regards simon manning.

[Fabrice Le Roux]

Paul,

Sorry missed it. Got a link?

Talking of tracks, check this specialist German foundry out. http://www.giesswerk.de/english/e_index.htm

Almost tempted to switch to 1/10th!

cheers, Fabrice

[Paul Wills]

Hi Fabrice,

Yes here's the gif, and here is a link to what I used it on http://www.youtube.com/watch?v=ZTd98OpucWM


Nice link, but I will stick to 1/6th. If the goverment keeps makeing cuts to our armed forces, our 1/6th scale maybecome the front line

Hi Simon,

Thanks for your input, it was one of the first things I noticed. I have repositioned the bump stops slightly lower down, so they are behind the wheel when the suspention is under load.

Paul.

[Fabrice Le Roux]

Nice work Paul.
I always did wonder how the graticule worked.
That foundry does have PzI,PzIII, PzIV and SdKfz251 tacks in 1/6th, but start saving (or wait for the Euro to crash!).
cheers, Fabrice