Landships II

Are you wanting the sizes for a large scale r/c model? I suggest printing yourself off a large copy of Helen's Mk I plans and measuring the radius of the track horns. The radii of the sprockets and idlers will not vary greatly from these figures, and if measured at a large enough scale should give you as accurate a size as anyone could need for a model - ie nobody would be able to discern if not 100% exact.

One more comment, which I hope will help: the measurement trick suggests that sprocket sizes are the same for Mk IV and Whippet, likely too for idlers, so if you can get the info for one, I think you will have it for both.

Bloody hell you're right, I didn't actually notice that, duuuhhhh!!!

What a muppet...

Looks like the set-up on the Mk VIII:

http://www.landships.info/landships/tank_articles.html?load=tank_articles/Mark_VIII.html

Nice close-up of Sir Archibald minus tracks - whether it's useful depends if any design changes were made to sprockets from Mk I to IV

Sir Archibald

Two images just about showing the drive sprockets in which one can make out the outer toothed wheels to engage the tracks and the inner toothed wheels for the drive chains.

Gwyn Evans wrote:

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.... There's a version made of cast iron and a later version made from manganese,, and also some design differences were introduced during production....

Gwyn

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 Cast Iron sprockets are pretty common for industrial uses - the graphite flakes in the Iron is supposed to act as a lubricant in the bearing surfaces. The brittleness of Cast Iron might be problematic for a tank with lots of shock loadings on the transmission. I think you mean Manganese Steel - this is a very different material. Mn steels work harden - it's used a lot in the mining industry for the teeth on excavator buckets, etc.

Regards,

Charlie

I'm back and those horrible symbols have disappeared - I told you it was just me.

As I was saying before my hopeless internet connection interrupted, Mark IV drive sprockets were originally made from cast steel, but part way through production at Metro these were replaced by manganese steel sprockets. Actually, a small number of tanks left Metro with sprockets cut from boiler plate due to a severe shortage of cast steel ones. Obviously these wouldn't have lasted long and were soon replaced. There was also a design change introduced, because originally the sprockets are described as having six bolt holes, but this was later reduced to three. According to an account by a Tank Corps engineer officer, sprockets wouldn't last for more than 60 miles anyway, so I suspect that all the photos you'll find of sprockets fitted to Mark IVs are of the final three bolt hole manganese steel type.

Gwyn

Is this any better.

Paul

Hi Guy's thanks for the info you have put forward. The measurements needed are for the Friul modeling guy who i meet at Bovington. We spent nearly a day measuring up the tracks for the MkIV and the Whippet. He has nearly finished them but would like the measurements for the sprockets etc for both tanks, not the Tadpole at the moment, lets walk before we can run. Only mananged to get him to make these and i am sure if they sell well, upon modelers requests could get the track scale to 1/16 or so. He has had a look at the Emhar models which is about the only available 1/35 scale about in MkIV and Whippet which can be converted to RC  as well as normal modeling, unless you want to pay for the £100 kits in this scale. He said that the sprockets for both Emhar models are terrible so i asume he is going to make the sprocket set to be included in with the tracks etc. Once he has the info then production can start.

So far, I can get one of Bovingtons rear sprocket drawings for the MkIV tank but not sure about the front idler wheel which is smooth and toothless. As for the Whippett, not sure if they are the same (it would be good if they were but need to comfirm this) i also need to find out about the relief holes in both sprocket sets, one i have seen are elongated.

I sure if such things sell well and there's a demand as with anything else in the manufacturing world, then upon popular request you could have the tracks in any scale. Whenever i visit a modelling show i always bug the model manufactures, when are you going to make  this and that, produce a MkIV tank or a MkV etc or a 1/15 scale Renault FT-17 tank etc etc. The more people who do this, the more you get those dream models you always wished for to make the shops. No good dreaming about it, write a letter, e-mail. 100 modelers asking a model company to produce something would certainly make their ears prick up, if you don't do it, don't moan about it. I have done it and because of this you will have the chance to get metal linked tracks for 1/35 MkIV and Whippet tanks.

It would be necessary to have accurate measurements, as i have seen how this guy measures and takes photo's in detail etc, if he were to make a wheel that was not the real deal, then his modeling reputation would be on the line in reviews etc Modeling mazazines would say great tracks, crap wheels, most people here would be first to nit pick and rightly so.. The trouble with an out of sight modelled wheel i.e. not very accurate would be of no use to someone who may want to use them for maintenance or destroyed tank display scenario.

Now to pester the crap out of some poor company to get them to make a 1/16-1/15 scale Renault FT-17