1:32 scale Lancaster Mk.1 Hachette Partworks

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Hi everyone,

And just a hello to OI 45 for looking in. Thank you for your remarks. I can assure you that patience was never a natural virtue of mine but I certainly acquired it in spades on this build!

Well, those pesky taboo track arms were a lot more difficult and time consuming than I first thought. I think Terry saved me a lot of hassle when he reminded me that I'd overlooked them. I thought I would have just been able to add them to the gun mounts through the slits for the barrels but that proved impossible in practice. Fortunately though, I hadn't permanently attached the canopy dome to the base before Terry's timely reminder arrived. I definitely needed the turret dome-free to measure and fit the taboo arms correctly.



Once again the magazine didn't help with what they'd supplied.


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At first sight they don't look like much – like two bent tacks, in fact. In reality they're not too far off what the actual track arms look like in reality – just far too short after a test fit. My solution was to extend their length and the easiest way for me to do this was with brass tube.



I had found some good references on the internet for the length and positioning of the arms.

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As you can see here, they engage with the highest point of the fairing and they enter the canopy at an angle. Had I used the parts supplied they would have been about half way between the turret and the track.



First off, in scale terms, I had to work out the precise angle they should be at to clear the aircraft surfaces.

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This all looks a bit Heath Robinson-ish, but it worked out OK in the end. I lined up a piece of fishing line about halfway up the peg on the tip of the tailfin and the gun barrels, matching their elevation to that angle. I then had to fix that elevation of the barrels with masking tape. This was tricky as the slightest movement would alter their trajectory. There is also a piece of plastic rod sticking out of the track rod mounting hole. This I was able to bend and adjust to the correct position and angle to sit on the fairing ridge. This gave me my measurements and angles for the track arms.



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These are the track arms to the correct length and angle, which was, in this case, 30 degrees. The angled section is completely within the gun mount holes, as in the reference shot, earlier. However, they were still quite tricky to fix at the right angle and length as the pre-drilled holes were not both drilled to the same depth and were quite wider than the tracks. In the end, the best method I found was to fit one correctly, through trial and error, then fix it securely in position and line up the second one at exactly the same depth and angle, after first giving them a coat of metallic paint.



Next came the test fit.

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I positioned the turret in the fuselage and sure enough, both track arms sat on the fairing ridge and elevated the guns as necessary. In this shot the guns are angled towards the tailfin and clear the tips. I was unsure how much clearance they would have had in reality but guessed conservatively.



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This is the turret as it finished up, with the dome newly attached and showing the taboo arms more clearly.



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Finally, the completed turret, sitting in position in the fuselage. Incidentally, I had long assumed that the fairing was only there to protect the turret from air buffeting or slipstream. I never realized it was that particular shape because of the taboo arm track.



More next post.

Gerry
 
Nicely done there Gerry.
You're actually partly correct regarding the fairing; the first Lancasters didn't have the fairing, and the exposed mid-upper turret was subject to some buffeting. As the need for a safety track was identified, the fairing was designed to be aerodynamic, reducing buffeting and drag, and to act as a track for the gun elevating arms.
 
Thanks Wurger, Snautzer, Terry, Andy and Gnomey for your continued contributions.

SaparotRob, welcome and I hope you'll continue to enjoy the thread. And Darryl, lovely to see you've picked up the thread again. As you know, I've been out of touch for a while, and am wondering how your own long–term project is coming along?

I've begun to look at what work is going to be required on the rear turret. I've covered this before in earlier posts, but I never received an intact rear turret canopy – even after three attempts. All three arrived in bits. At first I thought that this was the fault of our postal service but after all three arrived broken I began to think the problem was with the publisher and I gave up after that.

Over the years, I've been aware of only four other builds of this Lanc on various forums. Three of these have had the same problem with the broken canopy as me and I never got an answer from the fourth build. I can only assume that there was a catastrophic accident at the factory or at the publisher's but they decided to send them anyway!

Here's some of what I got.



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These were the first two to arrive. The turret canopy should have been in two parts, back and front. The third sent arrived in six pieces – even the rear section was broken – and was so unusable, I threw it out.

I'm still thinking how I might salvage these into a complete turret but until I decide how best to do that, I'll build the turret interior. That should give a good platform, around which I'll reconstruct the canopy. Hopefully I can salvage and use at least some of the frame sections and re-glass anything that's cracked or broken.



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Here's what was supplied for the interior. As I am now the proud possessor of three sets of these – they arrived with the shattered canopies - I am confident I can adapt one to make something more like the actual rear turret.

A and C are the back and front of the main structure. B, is the turret floor and seat. D, the gun mounts. The more astute will notice that they have included only two gun breeches but that should be fixable from one of the spare mounts. I also need to get rid of the plank between the breeches and I'm not sure that the axel supplied for elevation is the answer. The gun barrels will be replaced by brass barrels and the spent cartridge chutes may be replaced by metal ones.

I have some very good references for the rear turret, interior and exterior – probably the best of the three turrets – and including a walkabout of the turret on the East Kirkby Lanc, sent to me by Terry (Airframes) some time ago. There is no comparison between the real turret and what I received and I think a lot of adaption is going to be required.



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I've made a start and here's some idea of what needs to be changed.

A. These sections should in fact be transparent. B. The triangular sides need removing to improve the profile. C. This section bears no resemblance to any references I've seen. Is it possible that this was extra armour on some Lancaster marks? D. The seat needs to look more like the real one. E. Another solution to hold both gun mounts so that they move in sync needs to be found, as the axle will be right in the gunner's line-of-sight.



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This is just a dry fit of this first basic work, with one of the broken pieces of canopy, to show how it's shaping up.

The next two shots show some more work on the inner and outer gun mount frames with off-cuts of metal and plastic sheet, again to make the profile more correct to the original.



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In the foreground are the frames for the other side of the turret. All of these need a bit more cleaning up before I fit them permanently. I have to be careful that the outer frames are thin, as the fit for the canopy is very tight at the sides.

The white bars at the back are supports for the new seat.



That's as far as I've got so far. I'm still scratching my head over some of the other installations. I'll post again when I get some more work done.



Slán,


Gerry
 
That's looking great so far Gerry.
Should be fairly straightforward to mould the main shell of the transparency, and then cut and fabricate s required.
 
Terry, thanks for that. Your references were extremely useful to get a feel for the turret layout, both exterior and interior and Andy, thank you for that interior photo. It all adds to the overall picture of where things fit. I'm currently looking at the position and structure of the ammo feeder chutes, so it was helpful.

And Gnomey, thank you for all your regular, positive posts.

Gerry
 
Andy, that's great! It is the one significant part of the jigsaw I was guessing at - what was going on behind the gunner's 'dashboard'. I'll try to replicate something that looks like this.

Best regards,
Gerry
 
Glad to help. This particular FN-20 was undergoing restoration when I photographed it. Here's the same area shot from the opposite side through the perspex.

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And another:

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The attached file, a diagram taken from a very poor copy of the FN-20 manual, show the arrangement for the gun elevation pistons, the shaft and crank arms of which you can see in the latter photo.

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Hope these help.
 
Fantastic work Gerry, it's been too long since I've taken a look here
The two "horns" that protrude from the gun mounts, which have rollers on the ends. They move along the surface of the turret fairing, or "Taboo Track", deflecting the guns when they're in-line with the fins, wings or other parts of the aircraft structure.


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The B--24 upper turret had an internal device that did the same thing called an interrupted cam according to my dad. He told me once that his bomb group received some Ford built liberators that they were missing on. They found out about it the hard way when one of the gunners shot up his own tail.
 
Andy,

Thanks once more for sending the extra shots of the ammo feed system and the diagram of the inner structure. Both were very useful.

Glen, good to see you drop in again. That's very interesting on the B-24. A long time ago I built the B-17 and B-24 and I was thinking as I built the Lanc turret that I had no idea how the US aircraft tackled the same problem. I could only assume that they had a system similar to the German interupter system that allowed the Luftwaffe to fire through their spinning props. I assume that the system you mention was an electronic one?

Anyway, back to the build. After a lot of trial and error I have finished the basic structure for my turret and have arrived at the point that I need to paint before I can complete the interior.


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You may be able to make out that I tried to add something that resemble the gun sight rocking arms to the inner gun mount support. Andy's diagram was very helpful in working out the mechanics for this. An oxygen regulator has also been added to the front of the turret.


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At the back, the gunner's firing control yolk and an instrument dashboard are installed. I should say that this is still a test fit, as I need to paint some of these assemblies before they are permanently fitted.

Having seen the photo, I'm unhappy with the thickness of the seat. It looked fine life size but I think I'll have a look at somthing thinner before I fix it in place.


I next tackled the gun mounts.


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I needed to lose the large piece of plastic connecting the breeches at the back but first I needed something to tie the two sets of guns together so they would continue to move in sync with each other when the connection was gone.

Here's where I took some 'modeller's licence'. The gun sight mount is really connected to the rocking arms as per Andy's diagram, however, by connecting it directly to the gun mounts, it fulfilled the purpose of holding the two mounts in sync and also allowed the sight to follow the gun trajectories. It would have been static otherwise.

Next, the two outer breeches were added making sure that they sat slightly higher than the two inner guns. As you can see, I needed to pin these in position with brass rod and some filling was required to tie them into the mounts. The central elevating axel is there to afford some stability while I'm still working but I should be able to lose it when they're permanently mounted.


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After mounting the scratch-built gun sight I set about adding the replacement Master Brass gun barrels. This just needed some care and patience. They needed to be accurately positioned on three planes: First, from the top, they needed to line up with their breeches and be parallel to each other. Then, from both sides the height difference from the outer and inner guns needed to be apparent and they needed to be in line with their breeches horizontially. Finally, from a viewpoint looking straight down the barrels, the height and separation between the inner and outer guns needed to look consistant.

To achieve this was slow and painstaking as the pre-drilled holes in the mounts were sized for the fatter plastic barrels supplied. The brass mounts were too thin to fit snugly in the receiving holes, so each gun had to be held and manipulated to the correct position as the glue hardened and only when fully set could I move on to the next one.


We'll end with a couple of shots of the whole assembly, so far, test mounted.


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Most importantly, the elevation of the guns isn't impeded by any of the other equipment. This was always a nagging worry during the build.


The only other thing of note is, on the triangular supports on the outer mount frames, I replaced my badly freehand cut plastic circles with brass discs that I drilled through out through their centres. I think the effort was worthwhile, as they look a lot better. There are two bracing struts from the seat to the inner gunpoint supports, these will probably be the last things installed.



That's it for now. I'll paint and finish the interior and get on to trying to salvage the canopy.



Until next time , best regards,



Gerry
 

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