SE5a CONSTRUCTION BEGINNING TO . . .

[Guest]

Very neat Grahame and your thoughts on servo installation being an afterthought made me smile. I agree they should be an integral part of the original planning on any model and a part of your initial dry layout investigations.

There again I think I have changed the steam boat options about three times so far and I haven't fitted them yet!

[Greyhead]

How true Richard; my original drawings just ensure that the construction leaves enough physical space for the radio gear in a position where it won’t be too obvious, the exact positions of the individual items is continually updated as the build progresses but there comes a time when you have to make the final decision!

[Greyhead]

All the interior work is completed for the rear of the fuselage so the sides can now be covered; this involves a couple of things that I’ve never done before. The cockpit decking is fixed using dome headed screws that are then covered with the linen and the fuselage sides are laced, so I did some tests to try out my ideas first but no “in progress” photos because I didn’t know if the ideas would actually work!





My first idea for the screws had been to use a thin strip of litho plate embossed from the rear but I rejected this because the strip would show through the Solatex, pins would need holes drilling at least partially through the longerons so that was out. In a previous post I mentioned that I’d bought some very small beads, they’re called “Accent Beads”, from a haberdashery store and these have indeed proved to be the answer. I made a small indent using a blunted pin, filled it with slow cyano and placed a bead into it using a dampened toothpick to pick it up. From this photo you can judge just how small these beads really are.





Tomorrow I’ll start on the lacing.

[wonwinglo]

Very realistic Grahame,if I can at this point explain a bit about these devices and their real purpose-

Take a look at many pictures of World War 1 aeroplanes,and you will quickly notice that maintenance in the field was far from perfect,in order to be able to inspect and more especially repair broken longerons etc the fabric was placed as a bag onto the fuselage,the sides and belly had flexible metal cleats made from what is best described as a malleable lead like material,if you want to inspect even today these applied in a relatively modern form take a look at a Tiger Moth belly,or a Rapide underside,you will see how beeswaxed twine is pulled between the cleats and the fabric pulled tight,at the end of the run it is simply looped around the cleat,then a fabric strip is applied over the twine and cleat combined,why beeswax ? well this easily takes and adheres to aircraft cellulose dope.

You can quite often see where an over zealous application of pulling the twine,has caused the fabric to buckle on WW1 machines,the correct way is to soften the doped area by applying a dope remover and then to stretch ! nine times out of ten not enough time in the field to do the job properly and that awful crinkled finish appears as is evident in photographs taken at the time.

These days with metal monocoque construction only small round opening panels are needed to check the integrity of a structure,back then things were a bit more basic.

I hope this explains a bit more the purpose behind those little beads that you have used,that represent an important part of these wonderful old biplanes.

[Greyhead]

Barry


Thanks for the information; knowing what all these “scale bits and pieces” do in the real world is a true fillip and adds greatly to the enjoyment of building a scale model!


Grahame


The first job for the lacing is to make a hem on a strip of Solatex; here the fold line has been drawn with a soft pencil and a start made on folding, adhesive-to-adhesive.





When the folding is complete the hem is stuck together using the bare minimum of heat for the iron, we don’t want any shrinkage that would cause bending, then the non-hemmed edge "frayed". One strip is ironed in place first but of course the hem remains unstuck and can be lifted to make the stitching easier; this photo also shows the results of the beads once covered.





The next strip is ironed in place using the first as a guide, the stitching positions marked and pilot holes made with a pin. I found the easiest way to proceed was to stitch about 5 or 6 inches, leaving the stitches very loose, tighten 2 or 3 inches then continue stitching and tightening in sequence.





When the lacing was completed, as far as I can, the whole lot was given a coat of thinned dope to seal everything together. At the wing joints there is an aluminium cover, which is riveted to the front but held by the lacing for the rear section, so the lacing will have to wait until the wing stubs are covered. This will not be until after I’ve confirmed the positions of the wing bracing wires so will be some time yet!

[wonwinglo]

Well Grahame,the whole lot really looks convincing,the fraying so typical of this period reproduces remarkably well in Solartex,an added bonus is that it adds quite a bit of longitudinal strength along those longerons when doped up.

Just a question? do you purchase your ply and balsa locally,it all looks such good quality material and well selected.

That is one advantage of the shows where you can grade your timber,but good suppliers these days are getting tricky.

[Greyhead]

I do try to support my local model shops where possible, if they close through lack of customers I’d have to resort to mail order etc. which is generally cheaper but not if you just need a couple of “quick links”. I tend to browse the wood section whenever I’m there and if there’s any “good stuff" I buy while it’s available to add to my own stock, it'll always comes in handy at some time in the future.

I have to admit that for my new transmitter I did buy mail order because the saving was too great to ignore but Stockton Modeller has started to give a 10% discount for members of TMFC so they are now quite competitive even for the more expensive items.

[wonwinglo]

Grahame,you are very lucky to have a local model shop,we have nothing of note here around these parts now despite the sheer size of the outlying towns,the last shop had been operating for years,then changed hands,only to close in mysterious circumstances literally overnight.

Most of the other shops stock very little timber,I am fortunate that having built up an healthy stock of balsa over the years when I spotted good stuff.

The old type model shops are fast declining.

[Guest]

Grahame the covering is looking amazing and incredibly realistic. Mainly due to the fact that you are almost building it in exactly the same way as a real aircraft!

Beautiful job, many thanks for sharing as always.

[Greyhead]

Being the “fair weather” flyer that I am there’s no chance that I’ll venture to the flying field in the next couple of months so it’s the ideal time to remove a Laser from one of my models and get the front end built.


The engine will be bolted to this 2mm Paxolin plate that in turn is screwed to hardwood bearers; there are doublers where the bolts and screws go.





The Paxolin is plenty strong enough to support an engine spinning a well-balanced prop but in the case of a crash it will break before the engine crankcase mounting lugs. (I’ve seen some ARTF trainers with engine mounts made from aluminium easily twice the thickness of the lugs; I just hope they don’t ever crash! Having said that most also seem to use MDS engines so maybe it wouldn’t be such a loss!! Sorry if you happen to like them!!!)


When the plate is screwed in position it adds greatly to the overall stiffness of the front; not that it was weak in any way before. The carb and exhaust are not “set” for this model, in fact I’ve not yet decided whether to use the standard exhaust or make a custom job.





I always use an air filter, when you think about the size of the hole through the carb at full throttle and the amount of dust etc. that gets thrown up during take off I think it makes sense. A small stone would play havoc with the insides of your engine, especially a four stroke; filters are cheap, a new cylinder head isn’t!

[wonwinglo]

Grahame always take great care when using Paxolin,I lost a wormate who breathed in the dust which poisoned his system,so whatever you do take precautions.

A suitable safer alternative is layered sheets of domestic work surface.

[Greyhead]

Paxolin has a degree of flexibility whereas Formica type laminates are quite brittle but as is often the case the perfect material for a particular job has some health and safety issues, in this case quite serious ones; that is why it’s no longer available from your local model shop and has to be bought "trade".

I always wear a dust mask when cutting or sanding Paxolin and if possible do it outdoors; the same goes for sanding balsa and plywood but to a lesser degree.

[Greyhead]

I’ve not yet decided on the best method for making / attaching the cowl. The engine cylinder heads project through both sides so the alternatives are to make one unit complete with cylinder heads or individual sides with the cylinder heads attached and a separate top; both methods have their pros and cons but as the starting point is the same for both, the decision can be put off till later.


The initial framework is constructed using the fuselage as the “template” to ensure accuracy.





At this stage the framework is quite flexible so it is firmly wedged in position before the 1/16th balsa skin, which will give it its rigidity, is added.





The rear of the cowl buts up closely to “F2” and what cannot be seen in the above photo is the cling film used to stop the rear former being inadvertently glued to it. The front former is set back because the final litho plate skin will have slots to clear the cabane bracing wires and fuel pipe so the cowl will have to be slid back into position.

[Greyhead]

A late Christmas present arrived yesterday, a shiny new computer, so not a lot of modelling is getting done at the present whilst I load programs and transfer data etc.


The cling film did its job of stopping things gluing themselves together when the 1/16th balsa top sheeting was added.

[wonwinglo]

Useful material Cling film,I have used it a lot for release of forms on blue foam patterns,lends itself well to the brown paper/PVA paper mache technique,you can also apply heat to ease it around the former.