No 1A de Haviland: 1/32 stripdown Airco DH 1A

Stevef
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4 years 3 months ago #296 by Stevef

I have also added the internal rigging to the top wing:

The moment of truth is approaching when I will have to mount the top wing and turn this monoplane into a true aeroplane but I can delay it a little longer because I still have to attach the fuel tank to the top wing, prime the lower booms and paint both lower and upper booms grey, make some more struts, (some which I had made previously are too short!) and varnish the struts and add the maker's markings. By then I will run out of things to do and I will have to get on with jigs and the wing attachment.........wish me luck!

Thanks for looking.

Stevef.

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4 years 2 months ago #297 by Stevef

The black dots are transfers from Arctic Decals which represent the makers mark (Aeroplane Manufacturing Company): they are so small that I could just as easily painted black dots!

Next I had to drill holes in the ribs again to take the rigging as I intend to thread the wires under the strut ends. (I had already drilled the holes in the ribs before I glued them to the spars, but somehow most of them had become blocked. I did not want to have to drill them again when the top wing is in place as it is difficult enough drilling the holes in the ribs when they are attached to the spar and there is space around them). I am not using turnbuckles for two reasons, namely I cannot fix them to parts of the frame as it is made from brass into which I cannot drill small enough holes. The second reason is that I consider them to be too large in 1/32 scale and they are just too small for me to thread if they are 1/48 scale!

Lastly I made the rudder: I had wondered whether to wait until I had mounted the top wing but I decided that I needed the rudder post to help hold the top wing in place when I add the struts: more on that later. Construction of the rudder frame was straightforward: the post is brass rod and the ribs are 40 thou card for the larger rib and 15 thou for the rest. Those which were attached directly to the rudder post had holes drilled:

The ribs were CA'd to the post and the spar sections cemeted in place (these were pieces of 15thou strip), while the edge was made from 10 x 20 thou strip which had been run through a pair of tweezers much as clothes makers run ribbon across scissor blades to make the ribbon curl. When the curvature was nearly correct I secured the top end to the top of a rib and allowed it to harden.

Then I could bend the strip around and secure it to the rear ends of the ribs and spar with liquid cement and finally rudder post with CA. A small strip was added to the front to represent the balance:

The rudder assembly was painted to complete it:

I made a jig from my usual expensive and sophisticated materials ie, pieces of card and a block of wood with nails. I try to demonstrate in my builds that scratch building does not have to involve expensive or complex jigs or tools, although if you have the money and skill to own and use these they undoubtedly can be advantageous. I use simple tools and materials which are available to hand and cheap and simple to use: high levels of skill are not required - just a little imagination and patience. I hammered some nails into a block of wood to hold the model steady when I made my 1/32 Vickers Gunbus: I used the same block again. The nails are spaced so that they lock on opposite sides of the wing spars and fit into corners where the ribs are attached to the spars. This holds the lower wing and nacelle sufficiently rigid to stop it moving around when working on the sub-assembly. but means that the unit can be put on or taken off easily:

The image shows how the nails hold the wing in place - there are two pairs of nails - one for each lower wing. With the lower wing rigid the upper wing needs to be held while the struts are inserted. To keep the correct height, and to support the booms at the rear and keep them correctly spaced too, I cut three supports from thick card. Two sit on the lower wing and have a tab so that they can rest on the top surface of the wing and be held stable with a tab. The lower part has short feet which rest on the wood block, and the top has a cut-out which fits on the leading and trailing edges of the upper wing spar. The boom jig (centre) has a cut-out which is wide enough to sit over the lower booms and support the upper boom just in front of the tail plane:

The narrow shallow cut-outs in the wing jigs are there to sit over the thin strips which runs along the centre of the wing surfaces.

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4 years 2 months ago #298 by Stevef

Just card and nails....

With the top wing firmly held I could fix the rudder in place. This held the rear of the assembly steady and formed one leg of what would become a triangle. (The boom strut was only put in place and not fixed when this image was taken):

Unfortunately it also showed me that I had cut the lower booms too short - the rudder post should be vertical and it was not! However I left it in place until I had put in all of the wing and boom struts and had a rigid structure. I inserted one front outer strut and one rear inner strut to each side:

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4 years 2 months ago #299 by Stevef

followed by the cabane and boom struts:

The rear card jig and rudder was removed from the rear when all of the struts were in place - the structure is completely rigid and can be handled with care just like any other biplane model. All of the struts are square and vertical from the front and side, which makes pushers easy to assemble using this method:

The lower boom ends have been extended by taking a small triangle of 60 thou card and filing a V into the base side. The corners were rounded with a file and the piece CA'd to the ends of the booms. The fin also had to be adjusted to allow for the new angle of the rudder post. Finally the lower spreader strut could be CA'd between the lower booms and the sub-assembly is complete and ready to rig:

I will be pleased to be able to get rid of those dangly threads and the rigging of the wings will further strengthen the structure. The wings will be held on the wood block while I am inserting the threads through the holes in the ribs and the plastic fillers are added to the spars.

The undercarriage legs, axle spreader bar and wing skid are being carved from laminated pear and will be fitted after I have rigged the cabanes and wings, all of which I expect to take some time so the next update will not appear for a little while.

Thanks for looking.

Stevef.

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4 years 2 months ago #300 by Stevef

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Evening All,

I started to rig the wings which was a pleasure at it was getting rid of a lot of dangly threads which at times were a nuisance. As already explained I had drilled holes in the ribs under the struts so that I could pass the threads through them and hold them in place with CA. (I do not like turnbuckles as I think that they are too large even in this scale). I had rigged the inner bay on one side and was three quarters of the way to completing the outer bay when I managed to knock the tail unit with my hand....and all of the struts collapsed. I was left struggling to keep a single cabane in almost its correct position while I carefully set the fallen and now loose struts in order around the model. I do not mind admitting that for a few moments I thought that I was going to have to abandon this model. However after I had regained my composure I decided that a recovery operation would at least be worth a try so I set about replacing the struts one by one using the card jigs to hold the wings apart while I did so. An hour later and things were back to where they had been - and I stopped working on the model for a couple of days, which caused some of the delay. Having completed rigging the wings I put in the remaining pieces on the spars: these hold the ends of the rigging wires and block the holes in the ribs.

The plastic fillers were painted with the wood mixture that I concocted for this model. Next up was the propellor boss. I had ordered a resin boss but when it arrived it was too small. I am working from the DataFile drawings and I assume that they are correct and the resin boss is too small for this particular aircraft - certainly from the point of view of quality I have no problems with the resin boss and back plate. However I had to make my own from 20 thou card. I cut the discs by using a pair of dividers to score them out, drilled the holes and added the central bolt and smaller retaining bolts from plastic rod:

This is a bespoke fitting on the propellor - shown here as a dry fit prior to fixing permanently to the model.

The next delay resulted from trying to make the undercarriage legs and wing skids from wood. For the first attempt I laminated two sheets of pear and cut the legs of the undercarriage along the grain and tried to join them at the bottom. This was not going to work - the joint face was too small and I could see the whole lot collapsing just as I was about to finish the model. On the second attempt I cut out two sets of legs as V's ready to shape, and indeed did shape them and varnished them. All was going really well - actually too well because the legs started to warp! B......r. By now I was getting more than a little fed up so I turned to the wing skids. My original plan was to make them in three parts - two sloping legs and a cross piece along the bottom. I looked at the tiny pieces of wood and decided to save time and revert to plastic instead. So I laminated some plastic card to get sufficient thickness to be able to take the weight of the model and shaped two undercarriage legs and two wing skids. The spreader bar for the undercarriage has been shaped in pear wood and varnished as it will not take any weight and I was able to shape it along the grain of the wood. Two small pieces of thin wire were inserted into the ends of the spreader bar - these attach to the undercarriage legs as per the original aircraft. The axle will sit on top of the spreader bar and will be made from brass rod. The undercarriage legs and wing skids have been painted as per the spar additions described above. I had already made the tail skid which is also shown in the photo.

I drilled the ends of the undercarriage legs so that I could also insert small wire pins where they are attached to the fuselage nacelle. Now the joint is CA'd where the pins are inserted into pre-drilled holes, and the plastic has cement where it is in contact with the fuselage frame. Hopefully these joints will be strong enough. The cockpit step on the starboard front leg is also a short piece of wire. The extra dangly bits in the photos are control cables for the elevators: I have had to put the pulleys in place at the tops of the rear inner bay struts and I needed to put the cables on (they are EZ line) because I will not be able to do so later. Just more things to get in the way.......

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4 years 2 months ago #301 by Stevef

Finally I finished the instrument panel. This had been started as I had cut the semi-circle from card and painted it with oils some time ago. I made a compass from a piece of thick sprue and card and fixed a transfer to the top. The instruments came from the same Airscale sheet as the compass. The bezels were from HG models PE set. The backs of the instruments were small pieces of rod suitably shaped and painted and the ASI pipe and other wires CA'd into place. This will be one of the last parts to be fitted to the model but I had become so frustrated with lack of progress that I wanted to do something straightforward and have something to show the time taken!

I am hoping that the next post will be of a completed model: there is much time consuming work to do with very little of photographic interest, but I will keep a record of sorts and hope that I will not be too long. However I do have to visit family for a week shortly, so the next update may be a while coming.

Thanks for looking.

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4 years 1 month ago - 4 years 1 month ago #302 by Stevef

There are more photos in the show and tell section.

Thanks to all who have dropped by and given much support in the course of this build.

Stevef.

Last Edit: 4 years 1 month ago by Stevef.

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