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Post Info TOPIC: MK IV airship tug


Field Marshal

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RE: MK IV airship tug
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The additional piece looks like a large "L"-shaped addition that also has the ends flanged to transfer the load through to the extra built-up girders that go down the sides of the rear horns.  This would make sense, as the biggest stress would happen when the tank moves off to pull the airship out of the shed.  A suddenly applied load gives far more stress in the structure than a static load would induce.  The "L" piece could quite possibly be an inverted "T" to give proper anchoring space for the frame.  Very little welding was being done during WWI, so space has to be provided for bolting or rivetting.

Tony



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Lieutenant-Colonel

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These pics show my interpretation of the raised storage bin. I've taken shots from the same 2 angles (ish) as the pics of the real tank and they look to marry up ok. Couple of other pics too. Not finished yet but getting there. Needs an overall coat of satin now then some light weathering and bit of dried mud on the tracks. 

 



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Field Marshal

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LOVE to see the colour of your tracks - most people seem to paint them as mild steel instead of the carburised armoured steel that they were made of.  Also people often paint them with rust - they didn't rust!!

One query - should the tank have been fished in brown or green, or are you assuming the most likely scenario of a tank not sent across the Channel and therefore ionly n primer grey?

Tony



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Sergeant

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1st class, very impresive, I too am loving the tracks, they really look the part look forward to your weathering
Rich Reid

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Lieutenant-Colonel

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Cheers about the tracks. Kind of got there by error but they look ok i think. The tank I have done in a "mid sea grey". The thinking is that this was a Royal Navy tank not army. Early ww1 the navy used a very dark grey but mid war onwards this mid grey. Pure speculation on my part but seems reasonable for it to be in navy colour.

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This may be a daft question but why didnt the tracks rust on these tanks? Were they made from a non ferrous metal? I assumed they were steel.

 

Oops ignore that, just seen why :)



-- Edited by T140 on Sunday 27th of December 2015 11:03:37 PM

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Legend

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Tonys wrote:

LOVE to see the colour of your tracks - most people seem to paint them as mild steel instead of the carburised armoured steel that they were made of.  Also people often paint them with rust - they didn't rust!!

One query - should the tank have been fished in brown or green, or are you assuming the most likely scenario of a tank not sent across the Channel and therefore ionly n primer grey?

Tony


 I'm not sure the track plates would have been case hardened steel since the bending of the plates would have caused the surface to crack. Carburised steels do rust but more

slowly than mild steel. Track plates in WW2 were made from high Manganese steels which forged well and work hardened in service. Manganese steels don't rust but acquire a

dark brown surface. Anyone know which steel alloy the WW1 tracks were fabricated from?

Regards,

Charlie



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Field Marshal

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Charlie,

Very interesting to hear about the WWI manganese tracks - presumably still the case today

The matter regrading the carburisation of the tracks has been dealt with before and the very high carbon content absorbed into the track steel makes them blackish and almost impervious to rust.  In fact, the only tracks I found with any degree of rust were the ones at Aberdeen Proving Ground, which has a very corrosive climate.  Even then, the degree is fairly mild, especially when compared with the WWII which was being eaten away at a great rate of knots.

The carburisation process also came into play with the delay in fitting the Mk. V tanks with the 26,5" tracks because of production problems.  These were from the carburisation process which i9nitially caused warping of the plates.

Correspondence with Phillippe Gorczinskli on this point drew the following info:

That he thought that the tracks were cast iron because they were black and didn't bend but shattered when hit by shellfire; and

the rust on Deborah on being dug up was negligible to non-existent.

He also wrote about the Renault tanks being the same as this was mentioned in another thread regarding the armour preservation museum where the tracks of the Renault were having to be annealed to stop them shattering unexpectedly.

The attached photo shows a Mk IV in 1918 with the black tracks.

Presumably the the tracks fitted to museum pieces these days were made from mild steel as were most training tanks?

Regards,

Tony



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Lieutenant-Colonel

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Close up pics of track plates on the V** at Bovi. There is a broken plate on the tank which I thought I had a pic of but cant find it. I remember thinking the exposed edge on the break did look like it was a cast metal. 

 



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Corporal

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Tracks in use abrade, they are kept from rusting by being constantly ground against gravel, sand, etc. The alloys would also make a difference.



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Field Marshal

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The tracks at Aberdeen hadn't been moving for nearly a hundred years and they show only a light amount of rust.



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A pic of the underside pf those same V** tack plates at Bovi.

Definately some corrosion there on the hinges, but I understand they were a different material to the main plate itself. 

 



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Lieutenant-Colonel

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Not at all happy with how the finishing has gone. Tried something new for me and kinda mucked it up. Might need to start again with a re spray :(
Perhaps this model needs a rest lol.

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Legend

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T140 wrote:

A pic of the underside pf those same V** tack plates at Bovi.

Definately some corrosion there on the hinges, but I understand they were a different material to the main plate itself. 

 


Have been hunting and hunting for information on alloys and whether track plates were hardened (I don't think they were) but to no avail yet.  However there's a need to distinguish between the track plates and the track links.  This photo shows track links and these were definitely not hardened.

Gwyn



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Yes i did say they were a different material. I understand originally stamped then later drop forged. Theres a pic in the Haynes book of a broken plate on the Bovi mk v. It mentions the plates getting more brittle over time. Maybe from age or maybe use, not sure.

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Field Marshal

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The case hardening issue came up during discussion why the 26,5" tracks were delayed for the Mk. V and the initial ones were 20,5".  This was put down to the difficulty in manufacturing the bigger track - see CharlieC's post on: http://landships.activeboard.com/t55009397/mk-v-and-mk-v-track-widths/ where he says:

"If the track plates were armour plate the practice of the time would have been to press the shape out of mild steel and then carburise

the outer surface. The carburisation process was quite tricky to control and often resulted in distortions of the plate so the different

size ratio of the wider track plates may have given trouble in the carburisation.

Regards,

Charlie"

Also regarding the Renaults having the same problem, here is an extract from a post by BC312 on http://landships.activeboard.com/t52554479/the-weald-foundation-and-the-other-ft-17-tank/:


"I have for a few years been gathering information on the FT 17 tank, as much info as I can on the subject. This weekend I spent a Saturday afternoon with kind thanks to David of the Weald Foundation who showed me around the two FT 17s in their collection ready to be restored to complete working order for the WW1 celebrations, one of the FTs being a TSF radio model.
I have learnt more in an afternoon about the FT tank than I ever have over a period of years, especially about its construction and the process of its forthcoming restoration.
It was interesting to note how the armour plates had to be annealed to a mild steel state so the tank can be used in a safe way for its future preservation for many years to come. The armour becomes brittle over age as fragile like glass, similar to brittle cast iron and starts to form cracks in the plates, so it’s annealed to turn it into a mild steel state. After annealing the cracks are them weld filled..."

The only contradictory evidence is by David Fletcher, who claims that the Mk. IV was started off with the wider track, but the problems with turning the tank resulted in the 20,5" track being retrofitted.  This would seem to be in complete contradiction to the other entries above.

Regards,

Tony



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Legend

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I knew I'd regret getting involved in this...

I am not convinced that any of the above means that the track plates were carburised. In the post from CharlieC quoted he says "If the track plates were armour plated..." (my emphasis).  He doesn't say they were armour plated but only that they might be.  In the quote from BC312 s/he seems to be discussing armour plate generally and not specifically track plates.  I have no idea what the relevance of the statement from David Fletcher has to whether the track plates were carburised or not.  It seems an odd statement anyway since Mark IVs weren't originally fitted with wide tracks, and therefore I wonder if its been misunderstood.

It has been found over the last 100 years that the crystaline structure in WW1 armour changes becoming (as mentioned) increasingly brittle.  This is due to age, not wear, but it does increase the risk of damage from further wear.  This is why Bovington has decided no longer to run its Mark V.

Gwyn 



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Field Marshal

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Have been collecting info from some very kind people interested in airships and from Pulham St Mary's history centre.

Nick Walmsley, the author of pictorial history of R101 said ..." You may also like to know it was only used once or twice because the vibration from the combination of the tank and a rough airfield considerably damaged the structure of the airship.   Pulham was far more successful with the pair of Fowler ploughing engines that were in use there: one winched rigids down onto the mast, the other assisted with opening the shed doors." (my italics).

Still hoping for some better-quality photos from the history centre.

 

A hell of a lot of interest in something that was a washout!!!!

Tony



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Have just received 3 pics from Pulham.  These are taken from the photo plates that they have in their possession, and they answer a few questions, but raise even more!!!

Whether the detail will come out after the photos have been reduced by the website I don't know.  However, two of them are of photos already seen in other publications, but the high-fidelity photos provide so much more detail.  The other photo is of 261 looking pretty derelict, but whether it's after they used it as a tug or before, I don't know.

If the website's photo's are not of enough detail, I can send them by email if anybody is interested.

The main points coming out are:

1    The rear main legs do NOT sit on the unditching beam rail, but inside of it.

2     There is no evidence of any attaching mechanism at the top of the gantry - the bolts and plates are clearly visible.

3     The guy ropes for the R23 are attached at the rear of the tank - presumably on the "D-rings" by the sprocket bearing housing.

4     there are an incredible amount of people holding/guiding the R23.

5     There is a large baulk of timber attached to the rear of the towing rope box forming a firm fixing point.

6     The silencer seems to have gone over the baulk and cut short.

7     There seems to be some strange "silencer" or something immediately behind the front turret - goodness know what it is and for what.

Tony

Tony



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Colonel

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Most interesting. It's almost as if they tried to make a mobile mooring mast and didn't quite finish - or changed their mind and just used the existing shackles to make a temporary mooring (wouldn't have worked for long, if the wind changed direction, but would have been OK when moving the airship around). There's the question of how anyone was supposed to attach the painter (or hawser or whatever the main rope was called) to the top of the lattice - a tricky climb out in the field, but not too bad in the hangar. Or are we seeing the airship coming home, with the cables secured at a much more convenient level above the ground?

Are there any (later?) photos which show top attachments fitted on the lattice pyramid?

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Sadly there are no additional pics that i can find and how the airship was attached is the big unkown. I don't think it was intended as a mobile mooring mast, simply a tug for ground handling. This is a pure guess on my part but i will add a fixed length line running from a bar across the rear of the tank up to and through a hoop at the head of the mast then back down again. When not needed the excess can simply be coiled up in the storage bin. Typically ground handling lines were dropped from the airahips to the ground crews. I see that happening here then simply connect the 2 lines at ground level. The line can then be hauled up to the airship for easy release when ready to depart and just drop the tug line. No need for a winch or to climb the tower. A guess but seems workable.

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Legend

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Can agree with most of Tony's points, but the exhaust does not go over the rear timber - it follows the normal path through the stowage bin below the beam. The object sitting on the beam might be some form of towing hitch. It's hard to tell, but back in T140's inital post on page 1 of the thread, the photo showing the rear of the tank seems to show an inclined rod roughly in the middle of the rear, stretching from near the fuel tank to somewhere up the tower; this rod looks as though it may be attached to the object (hitch, or whatever) on the wooden beam. The rod, or whatever it is, is only visible in some photos.

As for the ropes, there are certainly some trailing low behind the tank in the first of Tony's pics, but the photo with the airship shows only one cable reaching towards the Mk IV, and that appears to approach it around the height of the rear bulkhead, above fuel tank level and well above the towing shackles by the bearing caps. I don't think the shackles are anchor points for ropes, not unless multiple points were used, with a single tow cable - in similar manner to the airship, where at least two ropes from the front of the keel are fastened to a single one (a Y-shaped arrangement).

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Field Marshal

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If you blow the picture up sufficiently, you will see the top of the gantry in fair detail - no hitching mechanism in place.

I'm awaiting more photos from the Pennoyer Centre which should show up more detail of my post of 20th Dec.

Sheila Moss King, a trustee of the Centre has very kindly commented as follows:

"I’ve had a look at Landships II and your post, and can add some information about the landing party (you mention how many people there are):

 

We know from Admiralty landing instruction documentation that landing was an extremely complex and potentially dangerous task, and for a ship the size of the R23 (163m long), 500 - 600 men were involved (I’ve counted them!).  From documentation and photographs it’s clear this was a very carefully drilled exercise, with every man having his position and role, and every one of the 20+ groups having a specific location and set of tasks to complete to safely land the ship.  There were, during WWI, 3,000 servicemen and 2,000 civilians stationed at RNAS Pulham, and given that a very small number flew, participating in landing duties must have accounted for a fair proportion of the workforce.  

 

There are tales locally of people from nearby villages participating in landings, being called to assist by fire engines and trucks driving through the villages ringing bells.  However, we suspect that this was later, in the early 20s, when the station was downsized, and that it could only have been on rare occasions when several ships required landing at once.  It certainly wasn’t a task for the uninformed, but perhaps they added ballast to the end of each landing team?

 

In terms of mobile mooring masts:

 

Pulham was an experimental station during and post WWI, and masts were one issue they investigated at length – bear in mind that there was the intention to use airships as the mass intercontinental transport mechanism of the future, to link up the ‘Empire’.  There was a main mooring mast at Pulham, some 200m away from the two large rigid sheds, and it was supplied via underground pipes with gas, water and fuel.  Around the remainder of the air station site there were multiple mooring rings, giant rings of iron embedded in huge blocks of concrete set into the ground, so that airships could be tethered out in the field.

 

Tank role:

 

There is no evidence, photographic or documentary, that the tank was used to help land – it was triailed to help tow the ship out of the shed or into it, as you can see from various photos, and as Nick says, wasn’t terribly successful.  The landing party would routinely take care of moving ships around, and yes, that could be fun on a windy day!  Interestingly, a landing party could also bring back a failed airship from beyond the air station (in the event of engine failure a degree of deflation was inevitable, but it was important to preserve as much gas as possible, given the time and cost of refilling) and they would simply walk it back over the fields.  In fact, there’s some fascinating oral history from Air Marshal Sir Victor Goddard, who was an airship captain stationed at RNAS Pulham in WWI, about trailing a towing mast on the back of a truck, for recovery of downed ships.  I live on the old air station site, in the former officers’ mess (and, less glamorously, the dept of works), and I can quite imagine the sight of an airship being walked around the country lanes, towed by a truck. "

Great background info.

Tony

 



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My towing rope added. Its one idea anyway and does not need anyone to climb the tower or any winches etc. Given that it was a test machine and there is a pic showing a rope or rod running up the rear and then one which hasn't got that I suspect they tried different methods which would make sense on a test vehicle. 



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Field Marshal

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I've been looking at the top of the gantry and attach a highly magnified scan with comments for people interested in adding a rope to the gantry.

 Tony



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Legend

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Might be something of that sort - I certainly have the impression that the tower may have acted as an upper anchor point for a rope attached in at least two places.

On a different note, Tony, when you posted your last three pics, you described the tank as looking derelict in the third one; I'm not so sure. The paint of the number 261 looks crisp and clean, and I've just noticed that on the grass verge behind the tank, there are two depressions and perhaps a faint tracks leading across to the vehicle - it looks like the photo was taken only a short time after the tank was driven into the ditch. Perhaps it was not being abandoned after the towing trials, but put through its paces by the crew prior to having the towing tower fitted? There are no obvious holes to suggest where the tower supports might have been, if it was an 'after' photo.

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Field Marshal

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Or naval personnel seeing if a landship could float???



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:)

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