Landships II

BC312 · Colonel

Wanted measurement sizes for ider wheels sprocket wheels for Mk IV and Whippet tank

TinCanTadpole · Legend

I don't have them, but I may have seen them somewhere, probably on a drawing, a few months ago (Mk IV I mean); a ballpark figure for the sprocket diameter is 23 inches if I remember. I've done some approximate calculations in the not too distant past (based on suitable-looking photos or plans) which I think gives a similar figure, whereas that for a Mk IV with Tadpole tail seems to be larger - around 27 inches.

If memory serves, I think the figure may be 23.5 inches for the Mk IV sprocket; I vaguely recall seeing such a figure and wondering why they didn't choose a round figure like 24 inches - 2 feet.

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Okay, I may be talking through a hole in my head cry ; Have just tried the measurement game for another approximation (using a detail plan for the back end of Mk I. Not Helen's plans, something someone else posted) and the result was 28 inches. That is an approximate figure, not exact, and seems to nullify my suggestion that Tadpoles had larger sprockets.

-- Edited by TinCanTadpole on Wednesday 23rd of May 2012 01:27:29 AM

-- Edited by TinCanTadpole on Wednesday 23rd of May 2012 01:28:18 AM

TinCanTadpole · Legend

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.

-- Edited by TinCanTadpole on Wednesday 23rd of May 2012 02:18:42 AM

MehdiT · Lieutenant

Try contacting Martin Langdon at Bovington, he has a bunch of Mk IV drawings, "EOC Drg No 22010 (19778) Road Chain Sprocket Pinion" should be the one you want. They charge for them, but I figured it was a good donation to help preserve the history of the tank.

hope this helps

Andrew

MehdiT · Lieutenant

p.s. the pitch diameter is 28 inches

TinCanTadpole · Legend

Note that Rob's last photo shows Mk V** tanks, which transferred drive to the sprockets differently - using chains inside covers on the inner external face of the horns, rather than chains inside the horns, as used up to V*. Nice photos.

Here's the rusty sprocket of the APG Mk IV

oops - that would be ROGER, not Rob - sorry!

-- Edited by TinCanTadpole on Wednesday 23rd of May 2012 09:03:27 PM

-- Edited by TinCanTadpole on Wednesday 23rd of May 2012 09:07:56 PM

Roger Todd · Legend

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

-- Edited by Roger Todd on Wednesday 23rd of May 2012 09:10:12 PM

TinCanTadpole · Legend

Another Mk IV sprocket, at the left of the first pic

here

It's not the clearest pic around. If you look at the Mk VIII pics on Roger's link above, there's an excellent shot of the idlers - probably not much different (apart from size) from those on other British tanks.

Wrecked tank
-- Edited by TinCanTadpole on Wednesday 23rd of May 2012 09:21:26 PM

-- Edited by TinCanTadpole on Wednesday 23rd of May 2012 09:34:48 PM

TinCanTadpole · Legend

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

-- Edited by TinCanTadpole on Wednesday 23rd of May 2012 10:04:28 PM

BC312 · Colonel

Messed up on posting

I am also after some photo's of the front and rear sprocket /ider wheels, a bit difficult to see as they are enclosed. Had a look at some of the excellent portfolios on this site but can't seem to see much.

TinCanTadpole · Legend

I think one or two of the pics of the APG Mk IV show part of the rusty sprockets, and there are period pics giving hints about the idlers, which have holes on them. Will see what I can find.

Roger Todd · Legend

I've attached the only image on my HD with even a glimpse of the front idlers, plus a blow-up of the relevant details. Probably not much help but it's all I can find (including books too, no luck there).

Roger Todd · Legend

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 · Legend

I have a few photos but am a little short on time tonight. Will try to post them tomorrow. Note that there isn't just one Mark IV sprocket though. There's a version made of cast iron and a later version made from manganese,, and also some design differences were introduced during production. Ultimately the final version of sprocket was the same as that used in the Mark V. However I've not made much progress yet in actually identifying the nature of these design changes. Will write more tomorrow too.

Gwyn

CharlieC · Legend

Gwyn Evans wrote:
.... 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

�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

Gwyn Evans · Legend

Yes thanks - I meant manganese steel, but was very short of time and didn't check before posting!

I'm having problems on this site tonight - all photos either don't appear or there's that blasted white square with a red cross (no, not the English flag wink ) Anyone else have this problem or is it me - it's usually just me.

Gwyn

Gwyn Evans · Legend

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

-- Edited by Gwyn Evans on Friday 25th of May 2012 08:20:39 PM

TinCanTadpole · Legend

Just noticed something else about the photos Roger posted: the Tadpole has different sprockets from the regular rear horn, as the short horn (moo!) has chain drive back to a pair of small cogs that engage with the sprocket teeth, whereas the Tadpole's longer horns have chains reaching the sprockets themselves.

On a different note, I notice the light shade the Whippets in that photo appear is very similar to the shades the heavy tanks are; clearly those four Whippets on the railway wagons are not green, but either grey or khaki. Grey presumably, they look a little paler than the lightest of the heavy tanks.

In the same pic, on the right above halfway there's a tank that would be interesting to see magnified and in higher res. It's a heavy with all the side armour removed, showing the sprocket, secondary gears, rollers etc.

I'd also say that with all those Tadpole sets produced, it's a shame that a pair has not survived; there are plenty of regular-length heavies around, even a V* and a V**, but no Tadpole. Given that it is often mentioned in books, despite not really being used, it would be good if a running replica was built to go on display and take part in shows for the public.

-- Edited by TinCanTadpole on Monday 4th of June 2012 03:23:45 AM

Paul Bonnett · Hero

Is this any better.

Paul

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Tank repair depot from Glanfield.jpg

TinCanTadpole · Legend

A little bit - thanks Paul.

BC312 · Colonel

RE: Wanted measurement sizes for idler wheels sprocket wheels for Mk IV and Whippet tank

TinCanTadpole · Legend

RE: Wanted measurement sizes for ider wheels sprocket wheels for Mk IV and Whippet tank

BC312 · Colonel

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 biggrin

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-- Edited by BC312 on Monday 18th of June 2012 09:24:28 AM

TinCanTadpole · Legend

Point taken - I just meant that if his parts are made accurately to scale, it is also required that the trackframes of the tank kit be equally accurate; since the tracks are to be made to fit a particular manufacturer's kit, there would also be sense in using measurements from that kit.

As to scales, we have different views amongst us regarding 1/16 and 1/15; Personally I think 1/15 a tad too large for anything bigger than a Mark tank, and even one of those would be quite big - 536.7mm long compared with 503.1mm at 1/16; hull widths 178mm against 165.9mm. Others disagree though, saying that 1/15 is suitable for use with 120mm figures - so, anyone want to share their thoughts, to give an idea which scale most people prefer?

Lothianman · Colonel

Just noticed that the tracks seem to be coming out -

www.friulmodel.hu/en/atl-146-whippet-little-willie-i247/

www.friulmodel.hu/en/atl-147-mk-ii-mk-iv-mk-v-i248/

BC312 · Colonel

As well as the metal track dream coming true, my dream of a 16/scale ft tank is now a reality thanks to Takom, all that praying did work in the end, who knows a 16/scale Mk 4 tank next for next year.

If you guys feel the need for a sprocket and idler wheel set to enhance the metal tracks then contact Friul models and let the guy know. It's you the modeller who motivates these people if these tracks sell well, which I hope they do, to do other great things. Anyone who does get a set of these track can you give us a review to what you think of them.

-- Edited by BC312 on Thursday 19th of December 2013 02:05:09 AM

-- Edited by BC312 on Thursday 19th of December 2013 02:06:39 AM