1/72 Blackburn Twin (TB) scratchbuild

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6 months 3 weeks ago #255 by Stevef
Evening All,

I have almost completed the Hansa Brandenburg W13 - I have to make a small base for it and am in the early stages of doing so and will put up photos when I have finished. The Britmodeller GB is continuing until late December so I have decided to attempt another contribution - this time a floatplane - which was originally suggested to me by Softscience on another forum last year. This aircraft certainly caught my attention and I duly added it to my list, so here goes.

You will quickly see that this is another of those wierd and little known types that fascinate me and for which there is no kit (at least as far as I am aware). Of course it has a spare wing but also two fans at the front: in fact it seems to have two of pretty much everything: wings, engines, fuselages, tails, main and tail floats, cockpits, etc. It was designed like this from the start - not a cobbled job from existing airframes like some of the WW2 types like Bf 109Z's, Mustangs. Heinkel Zwillings, etc. Blackburn's first design set a trend for unconventional, unorthodox and in some eyes ugly aircraft for the Royal Naval Air Service and later Fleet Air Arm, which continued to roll of their drawing boards for many years. It was called the Blackburn Twin this what it looked like:



Yes it did fly - just - but more of that later. In the meantime I am off to cut some plastic - I intend to use up some of the scrap odds and ends which inevitably accumulate from scratch building - some has already gone into the H-B but I want to reduce the pile some more.

Thanks for looking.

Stevef.

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6 months 2 weeks ago #256 by Stevef
Evening All,

A little progress to report on this build - I have started to make the floats and have cut out the wing blanks. I reported above that I want to use as much scrap pieces of plastic for this build as possible, but the wings had to be cut from new card as they are so large. So I took a piece of 30 thou card which had been bent in a pipe as described elsewhere and cut blanks for the upper and lower wings. The upper wing was considerably larger than the lower as the photos show: the outer panels were BE 2c parts (Blackburn was building BE 2c's under licence in 1916), with a centre panel to join them:



I have added the ribs from 10 x 20 thou Evergreen strip and drilled the holes for the struts and kingposts.

I also started on the main fuselage floats and am constructing them in a standard box fashion with re-inforcing pieces and strips along the top and bottom of the sides to stop the upper and lower surfaces pushing though when I come to fix them:



I will need to make two sets of floats for the front and two for the rear - more later.

Thanks for looking.

Stevef.

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6 months 1 week ago #257 by Stevef
Evening All,

The floats have been assembled and completed. These were two pairs (remember two of nearly everything....) front and rear. The rear pair are rather small and were made from 20 thou card rather than 30 thou. All needed a little filler around the edges but this will not show when they are painted.



I am making the fuselages one at a time to show the construction method and parts. The sides are 30 thou card cut to shape from the plans with a section cut and curved to fit over the lower wing.. I added some basic framework and a floor, seat and for the left (pilot's( side a seat and control column and IP. Card was used to make a series of bulkheads so that the sides could be cemented together: here is the partly assembled fuselage on the lower wing making sure that the fuselage/wing joint is not too uneven and the fuselage is the correct width:



A top and bottom surface was added. The I started to cut and assemble the observer's side which will just have a seat - I am not adding the fire extinguisher, (more of that later), as it cannot be seen and I am not sure what one would have looked like anyway!



The curved upper decking of the fuselage was push-moulded from 30 thou card. This mould was made a little too long so that I could also cut out the curved fairings which were fixed to the front of the fuselage behind the circular engine cowling. The mould was a single long piece which I cut to length and filed the rear end so that it slopes correctly behind the cockpit opening. the front end of the fuselage was blocked off with card to make a firewall. Liberal amounts of filler were used to complete the rear of the upper part of the fuselage and fill the odd gap between the curved upper decking and sides.



Finally the curved pieces which fit behind the engine cowling were cemented in place and more filler and sanding took place. Here is the completed pilot's fuselage and the semi-complete observer's. I also tried to mould some engine cowlings but after several attempts decided that I had not got the time to keep making awful units and so I dived into the spares box and found the last two which would be suitable:



More to come later.

Thanks for looking.

Stevef.

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6 months 5 days ago #261 by Stevef
Evening All,

I made two engines from a piece of sprue which I filed to the correct size for the centre and then added the cylinders from thick rod. I scribed the cylinders to represent the cooling fins and used thin rod for the push rods on the front.



The second fuselage was completed in the same way as the first and then I could cut out and add the fins to both. I also added the cockpit coamings at the rear from thin rod. The observant modeller will see just how much filler was needed to fair in rear fuselage decking on the second fuselage! One of the problems of these limited run kits is that sometimes the fit is not as good as WNW for example!!?





With the fuselages complete I could glue them to the lower wing. I did this one at a time and placed the wing and fuselage over the plan to make sure that all was correctly aligned: which I am pleased to report is the case!







Unlike the fuselages the wing to fuselage joints needed almost no filler at all - so sometimes limited run kits can be good after all. However the underside of the fuselage should protrude slightly below the under-surface of the wing so to make this look more realistic I cut some thin pieces of 20 thou card which were shaped to the under-wing profile on one edge and straight on the other. These were glued under the wing to align with the sides of the fuselages and then the gap between them had some card glued in place and finally liberal amounts of filler - which is even now setting so that I can start to sand and level it:



Thanks for looking.

Stevef.

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5 months 3 weeks ago #262 by Stevef
I have done some more construction work and painted the bulk of the model and it is beginning to look like what you see in the photos. I completed the horizontal tail unit by cutting and inserting between the rear fuselages a piece of 30 thou card with Evergreen strip (10 x 20 thou) ribs. I also added the small units on the outer sides of the fuselage plus the tail bracing, and then the two rods which were set between the forward parts of the fuselages: I assume that these were for the engine controls on the starboard side (the pilot sat on the port side).

Painting followed - mainly acrylics for the upper and lower surfaces but Humbrol enamel white for the floats because I have some left from the past and I find that it gives a better coverage than the acrylic paint. The struts were Revell SM 382 which is another enamel - I just like the soft brown to represent the pine of the struts. The cockades were home printed and the serial came form an old set of RNAS/RFC numerals from Pegasus. The rudder stripes were painted:







The white dots on the upper surfaces are holes for the struts. To put the top wing in place I used a procedure which I have found from experience is most suitable for multi-bay biplanes. I put some of the cabane struts into the lower wing - in this case the pair on the inner side of each fuselage, and the outer pairs of main wing struts. I used ordinary styrene cement and placed the inner struts against the fuselage sides first, then quickly added the two outer pairs and lowered the top wing. I had put drops of cement into the respective holes in the top wing. I was lucky because three of the fuselage struts fitted exactly and the fourth only need a minor adjustment. The outer struts were a little more fiddly but still went into place quickly. The whole assembly was jigged with paint pots to keep it square while it dried out overnight. The result was what I desired:





This structure was quite robust when dry and allowed me to put in the remaining struts, one at a time, without problems. After these had been put into place I again left the assembly for a couple of hours to set properly before I added the kingposts on the outer parts of the top wing:







The model is now ready to add the floats and that will be the next stage.

Thanks for looking.

Stevef.

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5 months 2 weeks ago #263 by Stevef
Evening All,

The rear pair of floats were fixed using 20 thou rod cut to length: first one side was fixed and then the other was made so that it matches from the side and longitudinally. The struts are not vertical so this operation would have been tricky even if I had been feeling normal. As it was I was suffering from a heavy cold which has severely curtailed both my patience and concentration: it took three attempts to get the second float properly aligned. The struts were painted after I had calmed down.





That left the two large floats at the front. These too had to match both from the side and be properly aligned longitudinally and again the struts are not vertical with respect to the bottom of the fuselage or thrust line. There is also a cross strut between the forward and rear pairs and there were fixings on the floats to allow the angle of incidence to be changed - this was an experimental type. Knowing from experience that fitting one float would be relatively straightforward I decided to tackle one side and then wait until I felt better before tackling the other. I will not give a blow by blow account but Burns' memorable lines about "best laid plans of mice and men" assumed significant proportions while I was trying to get even the first float properly aligned. The second finally submitted after a real struggle: I have not had such problems that these presented for a very long time. But they are there now....and the aircraft is a tail sitter! But I have a cunning plan - to which I mean that I intend to mount the model on small carriages and trestles as per the photos of the machine represented by the model when it was at RNAS Grain in 1916.







And before anyone comments I have still not properly softened the cockades on the upper wing: I have not had the patience left to deal with that yet!

When I am feeling considerably better I will rig this model and add the final details. In the meantime I am making a small base and the carriages and trestles which require much less concentration and can be picked up and put down easily.

Thanks for looking.

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5 months 1 week ago #264 by Stevef
Evening All,

I have been struggling with a cold/cough - the latter developed into a mild form of bronchitis which I am pleased to report has now almost gone, but it completely stopped me from modelling for a few days. I have a personal deadline as well as the GB deadline to keep to, so I have rushed a little to finish the model and put it on a base. I will do the necessary tidying up and finishing at my leisure after the seasonal upheavals are past. In the meantime here are some notes on how I finished the model and made a base for it - there will be more photos and some historical notes in the gallery later. I just want to finish this before I am overtaken by the GB deadline!

The first task was to rig everything. This was straightforward as it is basically a standard biplane rather than an early monoplane or pusher which tended to have rather more wires. I used rolled 40 SWG copper wire attached at the ends with CA. I am not sure about the tail control wires as I cannot see them on photos and they are not on any of the drawings so I have added what I consider to be the most likely pattern. The propellors which were carved from wood were fitted last so that they did not get in the way and thus knocked off.

The base is a piece of painted hardboard with an attempt to represent a strip of grass and a muddy track which is visible in the photos of the aircraft when it was at Grain. I will add some more weathering to the concrete base later - I will probably weather the Hansa- Brandenburg base at the same time. The trestles were made from 20 x 30 thou Evergreen strip and the wheeled units under the main floats were from scrap: all are based on those seen in the photos alluded to.



Thanks for looking.

Stevef.

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