Bristol Berkeley - 1/72 scratchbuilt - Finished!

[Jonners]

The basic wing shapes are there, but still a lot of work to do:

 

 

 

[pheonix]

Those wings look good, as do the radiator slats: I agree with Adrian concerning an alternative method - it works!

 

P

[Jonners]

Here are my three practice attempts at making the slatted radiator piece:

 

 

On the left is the first trial pice shown in post #48, using a craft knife blade to scrape angles slats. In the centre is my second attempt using the same technique, but with more effort to get the 'slats' closer together. The piece on the right uses Adrian's suggestion of angled and stacked plastic card strips (20 thou, in this case) to create the slats.

 

Each of these is quite rough - although they are only 1cm square! - so I think I'll be making some more. Although the stacked strips works, I'm quite pleased with the effect on the middle piece; this is quite quick to achieve, as long as the scraped grooves are equally spaced. Thoughts welcomed!

 

Jon

[AdrianMF]

23 minutes ago, Jonners said:

I'm quite pleased with the effect on the middle piece

That one gets my vote too. They all look great though.

 

Regards,

Adrian

[Jonners]

I haven't been able to find many clear photos of the port side of the Berkeley's nose, but those that are available seem to indicate that the left side of the nose radiator section also had vertical slats with a horizontal bracing bar:

 

 

These have been included in my final nose radiator piece, with slats made by angled scraping with a new hobby knife blade (apols for it being slightly blurry):

 

 

I used fine stretched sprue for the front bracing rod and 5 thou card for the left side bracing pieces and the 'wraparound' side and bottom panel. Fitted to the nose, it looks like this:

 

 

I also made the tailplane and elevator (no hinges or rib tapes yet) from 60 thou card with a suitable amount of scraping and sanding. Altogether, I'm starting to assemble a reasonable kit of parts:

 

 

Jon

Edited April 28, 2020 by Jonners

[pheonix]

That really is taking shape now Jon - you are approaching the point when all of the shaping and scraping leads to something looking like what you originally set out to make.

 

P

[heloman1]

Excellent work Jonners, I do like a man who is prepared to stick his neck out to build something he wants but is not available. Everything was so boxy in those days. Imagine the excitement when some designed returned from a continental holiday with a set of French curves. No more using pennies, halfpennies and farthings for radii! The shackles of the British aircraft designers new no bounds! STIC...

 

Colin

[Jonners]

Today's little modelling frustration:

 

 

That's the rear of the underside of what will become the upper wing. The Airfix designer clearly put the joint forward of the trailing edge on the original O/400 kit to try to ensure a sharp trailing edge.  Unfortunately this resulted in a join line that was, and still is, a bit of a pig to eliminate.

 

As I've also sanded the wing underside pretty heavily, both to eliminate the raised lines on the original moulding and to form a slightly concave lower wing surface, the joining faces at the annoying line are very thin. Even though I had applied plenty of cement when joining the upper and lower wing pieces, the joint split when I was sanding the wing. I repaired it with more cement, then applied and sanded down a good dose of Humbrol filler...then it split again. 

 

I thought I was being clever when I used Gorilla superglue gel to do a 'proper job', but it just meant that it was harder to sand before it split yet again.

 

After practising my Anglo-Saxon vocabulary I cut a not-very-pretty slot along the reluctant joint into which I cemented some plastic card strips in an effort to give the joint edges something to 'grab' onto:

 

 

Ugly, but hopefully it will work. I'll find out tomorrow.

 

Meanwhile, and a bit more positively, the tail surfaces are coming along nicely. Here the rudder and elevators are held in place with Blu-Tac:

 

 

That kit of parts is growing, slowly but surely.

 

Jon

Edited April 29, 2020 by Jonners

[SafetyDad]

Great work! Coming along nicely!

 

SD

[Jonners]

14 hours ago, Jonners said:

hopefully it will work. I'll find out tomorrow

It worked, as did the same repair that I made to the lower wing piece. Unfortunately, while I was sanding the repair on the lower starboard wing, the port side decided to split.

 

There's a word for that, which I'm not going to type.

[pheonix]

The wing problem is a real shame (another Anglo Saxon word which can be typed!). Just as I was thinking "those wings look really good" I saw your post. The one consolation is that the joint will be concealed: a. beneath several coats of paint and filler and if that is not enough, b hidden under the wing where nobody is allowed to look!

 

Anyway, this is such an unusual model of a type not kitted, most people will be so awed by the rest of your marvellous effort that they will not notice (hopefully).

 

P

[Jonners]

Thanks for the generous comment, P. Not sure anybody will be awed, though...

 

1 hour ago, pheonix said:

The one consolation is that the joint will be concealed: a. beneath several coats of paint and filler and if that is not enough, b hidden under the wing where nobody is allowed to look!

Yes, but I will know that it’s there and it would annoy the heck out me! Anyway, this morning I had another of those “of course!” moments when it occurred to me that cutting out the ailerons at this stage might well remove a lot if the stress that is causing the joints to crack, as the joint runs through each aileron. (This time I had today’s modelling lightbulb moment before I went for a run, so I went for a run anyway and pondered on other things instead.) 

 

I think it’s worth a go, so that will be my next task. The outboard leading edge of each aileron is curved so I’ll cut it in straight lines, sand back the concave wing curve and rebuild the convex aileron leading edge with plastic card. Fingers crossed...

 

Jon

[Jonners]

I think that I've managed to fix the wing-splitting problem, which is a relief, and all 4 ailerons have been cut out:

 

 

The process for the wings basically goes like this: sand - sand - sand - fill - sand - sand - check - sand - check - fill - sand -sand....etc. It's going to take ages!

 

As a break from sanding wings I decided to make the slatted section that can be seen under the engine bay:

 

 

I cut a rectangular section from the nose underside and cemented 60 thou  strips to the sidewalls to act as rests. I then pushed the finished piece into place to check how it fitted and found that it was so tight that I couldn't remove it, so carefully applied tiny amounts of cement to the inside corners with a sharp cocktail stick. The nose area now looks like this:

 

 

Enough of that for now; I'm off for a run again before it rains.

 

Jon

[Jonners]

Wing and aileron sanding has continued as tediously as before, but at least the parts are starting to assume the shapes and profiles that I want. As another break from sanding I've just done some prep for creating the wheels and tyres:

 

 

I will be using heavy-duty solder for the tyres, partly because it is the right diameter (as far as I can tell) and partly because I don't have any appropriate plastic rod. I've put a couple of turns around the shaft of a 9mm drill bit, So I'll see how I get on with cutting and glueing them.

 

I then cut a piece of 12mm dowel from a rod, drilled it and superglued a piece of aluminium tube into the hole to act as a shank. Once this was dry, I mounted the dowel in my Dremel and carefully clamped the Dremel in a bench vice. I then used this as a makeshift lathe to turn the end of the dowel to a very slightly concave 9mm diameter (something I've never tried before). I then used this to plunge-mould some wheel covers from 40 thou card.

 

Once again, fingers crossed!

 

Jon 

[Jonners]

There hasn't been much by way of obvious progress with the Berkeley over the last couple of days, but there has definitely been progress that isn't especially obvious...or probably interesting. Soz.

 

The tedious "fill - sand - repeat" mantra has been enlivened by the heady excitement of adding "prime" into the equation, which has highlighted all those annoying imperfections that are taking ages to sort out, but which must be dealt with now well ahead of final painting. The wings are pretty much done and ready for rib tapes, though the ailerons still need quite a lot of work:

 

 

Rather confusingly, the lower wing in the photo will be the model's upper wing and will be cut into three pieces to give a horizontal centre section and outboard panels with dihedral, and the upper wing in the photo will be the model's lower wing and will be cut into two pieces, each with dihedral and attached to the fuselage. Clear as mud? Good. I have some 1mm tape on order with which to try making rib tapes on both the upper and lower surfaces.

 

The fuselage has also been put through umpteen "prime - fill - sand - repeat" cycles and is also getting there, though the base of the fin is still rough and needs work. I made templates from 20 thou card and scribed the access panels on either side of the nose, although the engraved lines are quite grainy and will need tidying:

 

 

My first experimental attempt at making the wheels and tyres still needs a ring of either fine wire or stretched sprue laying in the joint between tyre and hub, partly to replicate the hub rim and partly to hide the ugly join. The primer coat showed up lots of little dents in the solder - probably the main problem with using this material - so tiny filler patches were required:

 

 

The jury's out: once again, more work required.

 

The elevators and rudder have been primed and, once the primer dries and assuming no extra tidying is required, they'll receive paintpen rib tapes. When the ailerons finally reach an acceptable standard they will also receive 'tapes' as well as hinge slots and mechanisms. In the meantime 'key worker' duties beckon again, so all that will have to wait for a few days.

 

Jon

Edited May 3, 2020 by Jonners

[John Aero]

Jonners,

 

If it helps there is no dishing of the wheel covering. It's simply a flat fabric disc laced to the Palmer wheel tyre hooks. Even the wheel rim will not show, as in the picture above.

 

look on line for Nitrile rubber O rings, there are simply thousands of differing sizes. Most of the sites such as Simply Seals have charts so you can choose OD, ID or section size. My Moth uses O ring tyres. You can scuff them but you don't need to paint them. I have various cast metal hubs but they can easily built up from laminations in Plastic card. O rings are ideal for Silver inter-war stuff.   Berkeley = 10 mm ID x 3 mm section. From Simply Seals.

 

I'll append a photo when i get back from my dog walk.

 

John

 

[John Aero]

 

A suitable tyre for the Berkeley and my box of O rings and Tyres for Diecast stuff. The shine can be taken off the O rings by just lightly rubbing them with abrasive. 

 

Another trick is if you can't find a totally suitable O ring but a slightly larger one meets the tyre thickness requirement, just carefully cut a segment out, so as to reduce the overall diameter to the wheel size then super glue the two ends accurately together. You should get an instant bond. The join will be visible but if you have put the ends together properly a light rub with a sanding stick will make the join disappear and when it's totally dry, you can still spring the tyre over a hub rim.  

 

I've made a simple Jig by sawing a piece of suitable brass tube length ways to produce an open ended trough, of  which one half is soldered to a small piece of flat brass sheet so that it won't roll. A lightest smear of soap will act as a release agent. Apply cyano to one end of the cut O ring and push both ends of the ring together in the trough by applying the lightest pressure and allow to set. Any slight skin of cyano is just sanded off. 

 

John

 

 

 

 

 

[Dave Swindell]

3 hours ago, John Aero said:

just carefully cut a segment out, so as to reduce the overall diameter

Oh, the number of times I've had to do that for lack of the correct spares!

We usually had a couple of these knocking around (missing the size of o ring cord you actually needed, hence cutting down O rings from the miscelaneous unlabelled gash o ring box)

3 hours ago, John Aero said:

then super glue the two ends accurately together.

the jig was useful for cutting as well as gluing.

3 hours ago, John Aero said:

You should get an instant bond

Remember also that whilst assembling it, the superglue will bond nitrile to flesh in preference to nitrile to nitrile, and the preference of a flesh to flesh bond is even higher...

 

[John Aero]

Hi Dave,

I have bought the nitrile cord separately but I find that making small O rings with thicker cord it's very difficult to make them circular so I find that using a pre-formed ring of a suitable close size is easier to keep the shape true and has less resistance to being re-shaped.

Been there with the bonding..

Cheers

 

John

[Jonners]

8 hours ago, John Aero said:

If it helps there is no dishing of the wheel covering. It's simply a flat fabric disc laced to the Palmer wheel tyre hooks. Even the wheel rim will not show, as in the picture above.

Good call, John; I wasn't sure from photos whether the dishing very slight or nonexistent. As for the advice regarding O-rings (and the brass half-tube idea), it's appreciated as usual. Thanks - that will be my next route so I'll track down some suitable rings. Still, although I've made something that is a bit rough and not especially accurate, it's good to build experience with new techniques.

 

2 hours ago, Dave Swindell said:

Remember also that whilst assembling it, the superglue will bond nitrile to flesh in preference to nitrile to nitrile

I'll bear that in mind, Dave...though I'm bound to end up with a 'nitrile graft' at some point!

 

Thanks for thd input, gents - all excellent stuff.

 

Jon

[Jonners]

8 hours ago, John Aero said:

Berkeley = 10 mm ID x 3 mm section. From Simply Seals.

O-rings ordered. Cheers!

[Marklo]

I’ve been using wooden buttons with plastic disks for the hubs. Although on my last few outings the spares box has provided.

The junkers and the Bristol used buttons. The Depredussin was a complex arrangement of discs and toroids of plastic card with a molded conical centre, lots of work and don’t look any different to the modified buttons  

 

the bottom picture is the Bristol wheels before paint.

Edited May 4, 2020 by Marklo

[John Aero]

On the O ring tyres subject,

 

This little exercise has just taken me about 15 mins. The donor ring is on the left, second left is a same with a segment cut out. Next two identical rings but now joined with Cyano but not yet sanded down. The hub is just a ring cut off a length of tube which needs a couple of concentric tubes to fill it down to the axle diameter and a facing piece. These are for a 1:48 Auster IV. The ring on the right is a standard  O ring but perfect for such as early Spitfires.  The Lledo Taxi has my O ring tyres on my cast wheels missing their hub caps, which replaced the horrid undersized gold wheels, as bought. I'ts 1:48 by the way.

 

 

[Jonners]

Thanks John, that's a really effective little tutorial. The O-rings that you recommended have arrived (I made sure I'd have spares for future use):

 

 

Meanwhile, I'm getting bored silly with fettling wings. I tried 1mm tape for replicating rib tapes on one wing piece but found the effect to be far too pronounced for 1:72 once primer had been applied, so I rubbed the wing down (yet again) and reverted to my Edding paint pen. Paint lines were applied twice, then a coat of primer, which has given this effect:

 

 

I'm quite pleased with that. I now have to do the other wing piece, and then the undersides of both. 

 

The upper centre section of the Berkeley was fitted with two metal fuel tanks which can clearly be seen in this photo:

 

 

I made a piece from a bit of old wing section and used it to plunge-mould 2 tank parts. Although this would make it relatively straightforward to make the parts conform to the curved wing upper surface, the sides are soft and rounded whereas the original had sharp corners. This is what I've made, but it might just be better to make some out of plastic card:

 

 

 Once again, more fettling is needed.

Jon

 

 

[pheonix]

Fettling is what scratch building is about! Try using the curves from your moulds and cut the sides from card: glue the new sides to the curved tops. Alternatively glue some thin stretched sprue to the corners and then plaster them with filler. Sand down the corners to a sharp edge. Saves a lot of time either way and it will give you the sharp corners that you need. I have described the method where I squared the corners of the nacelle of the FE 2d with sprue and filler here:

 

 

P