To understand the rationale behind this thread, it is worth reading through my 'Building the Mk1 Tank' thread. I would like to thank MK1 Nut for her inspirational drawings, my own limited resources and the help from all the other members of this community for being able to put this together. If you have read the thread suggested, you will see that I have gone much further with my own models but I offer this as a less challenging option. In essence it is all about loosing some length at the front and adding some length at the rear to correct the geometry of the X beam (sure there is more to it than that!!). Remember, if even this is too much, you can slap a bloomin' great storage box on the rear of the tail unit and hide all the errors!!
The photos should speak for themselves. Grrrrrr, despite uploading in the correct order the photos should be viewed in the order 1, 4, 3, 2, 5 - sorry, don't seem to have any control of that.
-- Edited by TeeELL on Wednesday 5th of February 2014 03:05:47 PM
-- Edited by TeeELL on Wednesday 5th of February 2014 03:06:30 PM
-- Edited by TeeELL on Wednesday 5th of February 2014 03:09:00 PM
Having completed my semi-scratch built steering tail unit I decided to start on the second unit following some of the advice from my previous post in this thread. I decided to sacrifice the axle as I have started the replacement H-section one. At the front the cut was made and the parts stuck back together (see photo). It will appear that the large lightening hole is now misshapen but the MB offering is too big, my plan is to fit a replacement plate and I have removed the rivet detail. I'm not going to do the bottom as it is unlikely that it will ever be viewed!! At the axle I have cut through on the diagonal thus I do not need the spacers, I've shaved slightly less than .5mm from the ends of the, now, extended X beams. My replacement axle is in the photo although it needs the reinforcements at the centre line and at the axle ends. (See photos in 'Building the Master Box Mk1 for clarification).
Just to clarify for anyone seeking to improve the steering tail. Helen's drawing shows the principle of operation and for clarity the wheel pivot points are shown inboard of the wheels. As Helen has previously explained and backed up with a photo, the actual pivot points for the wheels are within the hub. It is cause of the errors in both the MB and Airfix tail units. Please see 'Building the Master Box Mk1 tank' thread for additional information.
__________________
Regards TeeELL
Growing old is compulsory, growing up is optional.
I am not surprised the steering system was dispensed with, it strikes me that with the length of cable travel, a 90deg bend and then the tiller arm to contend with, tail wheels steering would have been bloomin' hard work.
__________________
Regards TeeELL
Growing old is compulsory, growing up is optional.
The rectangular bracing plates should have a rivet count of 13 from rear left to front right and 7 from rear right to front left. The X channel beam from rear left I assume was cut and affixed either side of its mate thus required extra rivets. The MB mould has an incorrect rivet count (as does, currently and unfortunately, the new etch offering discussed in a newer thread on this forum)
__________________
Regards TeeELL
Growing old is compulsory, growing up is optional.
The rivet count on the rectangular plate has always puzzled me since I first saw photographs of it. Although the arrangement is as stated, 13 & 7, I have wondered if this was typical, and if there are any clear contemporary photographs to confirm it. And why would it be done that way?
Michael, the X beam would be made of one single channel and one cut (making 2 short) channel. Where the cut channel joins (crosses) the single any welding would be minimal because of the channel cross section. So the strong, uncut beam, would require just the 7 rivets and the cut beam the 12 (the 13th being the middle one of the 7). On my next visit to Bovy I am going to spend more time photographing the tail unit - sad!
Helen has put some 3D drawings on the previously mentioned thread.
__________________
Regards TeeELL
Growing old is compulsory, growing up is optional.
This is one of Helen's drawings to show what I mean.
as far as other photos go, I daresay other proof may exist but the reality is we only have this one example to go on. After all, if you were a 1916/17 photographer would you be inclined to take a snap of a plate full of rivets
The tailwheel at Bovington is the real deal and pretty standard from what I have seen in period photos. Most photos of the tail system on the MK1's are either at the wrong angle, or there is a box in the way, but I do have one fuzzy photo that shows more rivets on one beam than the other.
The sharp eyed amongst you will have noticed that there is a simple modification to improve, yet further, the appearance of the tail unit - yes, that's right, the bit at the back that no one will look at!. At the front of the tail unit, at the point where the X frame joins, it is possible to remove the bulk of the centre portion of plastic leaving just the moulded L angle at the bottom (you may loose the steering tiller pullies, but save them for the replacement tiller). So having removed a lump of plastic it is necessary to replace a little on the top (essentially to match the moulded piece remaining on the bottom. For help in this please look at Helen's excellent drawing - plus any more she may post in this thread. The best way is to use a thin strip of styrene and emboss the 4 rivets each side, attach and then cement a vertical piece behind to create the L.
Sorry, but it will be a couple of weeks before I can complete this, photograph it and post it. Presently in the Sofitel Gatwick, Cuba tomorrow . Don't drown fellow Brits, and brave the snow!
__________________
Regards TeeELL
Growing old is compulsory, growing up is optional.
Thank you for the explanation. This is extremely persuasive, and solves one of the mysteries which had me wondering over a number of years. Now I can sleep easily!
Hi, Ive been following the various threads on improving the MB MkI and noticed a distinct lack of photographic evidence on the tail unit. In the far distant corners of my brain I knew I had seen good accurate pictures somewhere, albeit of a large scale model ? Then I knew where I had stored the pictures and thought they would be handy for people to see here. They are of a brass model and I do'nt know who the builder is so I am sorry I cannot give credit to him ?
Paul
-- Edited by Paul Bonnett on Sunday 16th of February 2014 10:40:39 PM
From memory it is the 1/15 scale brass kit by Perkins. One of the most accurate models out there, although it has faults, but that is to be expected considering I've been looking at these tanks for years an still finding out new stuff. The photos I think were the prototype, published by the manufacture in Japan I think.
The Tail gear looks very good. I had forgotten about this model. Thanks! x
Here's a pic of my build of the Firing Line MkI. The tail needed a few scratch built add-ons, including the hydraulic lines, underside beams which protected the tiller bar, the steering cables and attachment blocks, and the tubes through which the cables emerged from the hull. The model's tail is designed to slot into the rear hull plate, and this needs to be modified to give an accurate representation of the pivot joint which connected the hydraulic ram to the tail.
That looks a really nice job you've done there. I see you have the roof supports on, any more pics? Did you finish it?
Sorry for all the questions but it would be nice to see one of these kits built up, they really are a good model.
Ok I could probably like you pick holes in it, but considering the Bovington MK1 is not accurate or complete, it is proof of their good work that they got it that right.
I think that we were both right, Helen - when I bought the kit back in '95, Parkins' company was called "Firing Line". I agree that the kit is pretty good, and that most of the inaccuracies are due to alterations and damage to the Bovington MkI. I posted the photo mainly to point out the hydraulic tubes, which I suspect that some folks may wish to add to their Master Box kits. It has become a bit of a "shelf queen", mainly on account of a significant diversion into Warhammer 40K with my son. However, the interval has given an opportunity to research a few corrections, the grenade roof and the paint scheme. The current objective is to have a painted model posted on this site on Sept. 15, 2016!
I plan to replace the mesh on my grenade roof, as it should overlap the edges of the frame more than is shown in the photo. The two small square blocks of wood on the underside of the "wing" of the grenade roof (which allowed it to rest on the sponson roof) are also missing - thanks for bringing those to my attention.
It looks impressive and I hope now it will get finished. Any info you need just ask, but I think you have it sorted.
The pipes for the hydraulic gear was only a recent discovery for me. I knew roughly where it exited the rear of the tank, but couldn't seem to pin it down. Then while looking through an old book, I suddenly came across a photo that showed a nice clean MK1 just rolled out the factory door. Suddenly I realised one of my bolts on the back of the model was actually the exit point I couldn't find.
Oh just noticed, the blocks shoved into the Ubolts that hold the grenade roof on... not blocks... but as TCT mentioned, wedges. It made more sense once he pointed this out to me.
So much for my comment about not drowning!! Cuba and 5 days of torrential rain, albeit warm, saw fields flooded, crops washed away and holes revealed in the roofs of the accommodation!! Still, there was no leak in the roof of the bar so the Pina~coladas and Rum & cokes didn't get watered down.
Any way, back to the steering assembly, I have taken the decision NOT to carry out the modification my previous post suggested. Instead the MB tank will have a storage box mounted on the tail thus the incorrect number of rivets in the rectangular bracing plate will also be hidden. I am in the process of completing the 'Female' with the 'nearly scratch built' tail unit.
__________________
Regards TeeELL
Growing old is compulsory, growing up is optional.
I should mention that photos of the mostly scratch built tail unit can be found in the article on the Mk1 grenade canopy. I posted then in the wrong place !!!
__________________
Regards TeeELL
Growing old is compulsory, growing up is optional.
In my previous post but one, I declared that I was not going to undertake the modification I had suggested weeelllll ....... whilst waiting for the grenade roof supports to harden off I broke out the 'dremmel' and dental burrs and had a go at removing the bulk of the plastic. See photo. There is still much to do, the axle ends need re-attaching, the tiller needs to be made, the triangular bracing plates and top angle section require fabrication etc etc etc. but it compares well with the 'all but scratch built' tail unit on my 'Female' tank. The white styrene extensions on the X beam will sit over (and the bottom ones, under) the axle, you may be able to see that they pass over the thickened outer parts of the axle and will require drilling out for the 'securing bolts'. I am minded to set this tail up with a bit of steerage on, so I will have to create a flat V hollow in the wheels to give the correct appearance, remembering that the point of swivel is inside the wheel hub itself.
The photographs show the , now modified, tail unit as described above and the primed nearly scratch built unit on the 'Female'. You should be able to make out the 'securing bolts' on the axle of the 'Female' tail.
-- Edited by TeeELL on Wednesday 5th of March 2014 05:47:23 PM
Finally I have finished the second steering tail for the 'Male' tank. It is set at virtually full deflection. I will take some more photos tomorrow of the underneath.
-- Edited by TeeELL on Friday 28th of March 2014 12:19:26 AM
This is the last post on this thread I propose to add as I have completed the improvements to the MB tail steering unit on my second model. Tail unit and model are now primes and the tank will receive the camouflage. As with the 'Female' I do not propose to camouflage the tail unit and wheels - I am firmly in the camp of 'it wasn't done'. I have included the previously promised bottom views.
Â
I hope this has been a useful thread and that many of you will modify the MB tail unit to something a deal more accurate.
The latest information I have received from Helen (Mk1 Nut) suggests that the pair of holes in each of the thickened ends of the axle should pass all the way through. It seems I have been mislead by a repair to the Bovvy steering tail. So, please drill the holes all the way through.
I commend a visit to the Mk 1 drawings in the Reference section as Helen has just submitted her latest plans of the steering tail.
__________________
Regards TeeELL
Growing old is compulsory, growing up is optional.
For this I made a few of flat jigs to aid in the assembly of many separated parts. For instance, there's a large X wich sets the angle between the two main members. To this basic X made with styrene strip, I'll add several layers of details or plates detailed separately. Another jig sets the geometry of the "ends" where the springs are attached, and yet another serves for the general assembly.
I remain with two doubts: if using or not the provided Airfix "springs" (which are near impossible to clean up) and how is xactly the shape of the cylinder attached to the rear wall of the tank. I read somewhere that should be mounted upside down, but I guess that the kit part also needs some sort of refining as well.
Diego, please note that the Airfix instructions would have you fit the hydraulic unit upside down!! The instructions are wrong in both Male and Female tank. Oh, don't worry overly much about the finer details of the hydraulic unit - with the springs in place you don't see much of it, and why not fit the 'shield' that would help the disguise. Again, don't worry about the springs, once painted and weathered they are not going to be too bad, as I have said the Airfix springs are finer than those in the MB offering.
__________________
Regards TeeELL
Growing old is compulsory, growing up is optional.
Yes, I was aware of the upside down piece on the instructions... but hey, wouldn't be great to have this cylinder properly mastered and cast in resin as an aftermarket part? I intend to dedicate a few hours of this weekend fot the benefit of the Mk.Is... is I can finish painting the 155mm GPF cannon!
My son and I visited Fort Nelson, Portsmouth, yesterday. It is the home of the artillery museum, so spent some considerable time looking at artillery pieces of all ages. I called round to see 'Mk1 Nut' today and spent a fair amount of time viewing photos, her 1:6th scale Mk1 and all the CAD drawings she has done - the steering tail is even more complex than it looks!!! One such thing is the fact that the 2 pulleys on the front of the steering tiller are mounted one above (right side) and the other below the T piece.
I now have another MB 'female' ( thanks Mk1 Nut) so will build that along with the Airfix, heavily modified female, and produce identical tanks for comparison ( at least I will use the Airfix steering tail!!).
__________________
Regards TeeELL
Growing old is compulsory, growing up is optional.
I am probably going to get my wrists slapped for this! I have noticed some recent builds of the MasterBox Mk 1 where the modeller has undertaken some of the work necessary to correct the tail steering gear but hasn't done a full modification. Thought I had better 'bump' this for their benefit. If I am out of order doing this then I apologise.
__________________
Regards TeeELL
Growing old is compulsory, growing up is optional.
