SE5a CONSTRUCTION BEGINNING TO . . .

[Guest]

Truly a great example of model making at it's best.

I really admire your creativity and inspired use of materials too. It all looks simple after you get to see how it's all done properly.

Like the miniature dremel lathe...great stuff! The way you look at each piece of the project as a tiny model in itself, the finished model is going to be a real joy. It really looks to be a labour of love.

The attention to detail shouts out from a mile away.

[Greyhead]

The first former is made from 2 layers of 1/16th balsa glued together “cross grained”, this is a good method when some extra strength is required but it doesn’t warrant ply of even lite ply; it has a 1/64th ply facing on the cockpit side. The other notched former is from 1/8th lite ply as this is also the front fin support. The centre former is also “cross grained” balsa as half the stringers actually end at this point.





Only 2 formers are fully notched because it is very easy to slightly miss align the slots, which results in wavy stringers, not a pretty sight!


The centreline stringer initially holds everything in place. I wanted to use spruce for the stringers but none was available and the model shop didn’t have any idea when they could get any so I’ve used basswood; I don’t think it’s as resilient as spruce but needs must!





The fin rear post is only fitted temporarily; the fuselage end plates have been made oversize to hold the fin post and will be finally shaped when all the stringers are in place.

[wonwinglo]

Interesting that 'Balsaply' as it was called then,was in fact available from model shops back in the fifties-sixties,but production of this useful material ceased a long while ago,nothing to stop us from making our own stock,Scotch 3m spray adhesive is useful for this as it is very light.

Spruce is now a thing of the past and if you can find a supplier then cherish what he has in stock,its resiliance and springyness can never be surpassed,sometimes a word with the full size suppliers such as Slingsby Sailplanes,Kirbymoorside can bring in offcuts.

I like the early application of the sternpost to check to make sure that everything is in line,no easy task if something wants to twist out of shape.

Amazing simularity to a Tiger Moth in that last shot Grahame.

[Greyhead]

The centre stringer has had rear doublers and metal brackets fitted for attaching the fin; now to cut the extra slots and fit the rest of the stringers.


A length of cotton is stretched tight between the 2 formers already notched, the intervening formers marked and the slots cut using the Dremell with a cutting disc.





The stringers are added symmetrically; long right, long left, short right, short left and so on, this helps to avoid any unwanted twists in the fuselage.





The stringers stand proud of the formers apart from the first 2½, which will be ply covered, several of the stringers will eventually be removed from this area to save weight. But for now they add vital strength and it’s easier to get things even if all the stringers start from the same point.

[wonwinglo]

I like the stretched cord stringer locator Grahame,reminds me of the days we used to mark chalked lines onto the sides of aircraft to paint on the registrations,you outstretched your two hands between the two points with a knot in the centre,grabbed hold of the knot with your teeth,and twang ! as the chalk left the desired impression onto the surface.

[Guest]

Even a technique to ensure the stringers are perfectly true.

Is there anything you haven't thought about Grahame?

[Greyhead]

Over the last few weeks I’ve been doing a lot of thinking and considerable experimenting with rib stitching before committing to the actual model. Unfortunately the photos I took don’t really show anything of note; white thread on natural Solatex just doesn’t show up any differences!





The first question was “do I want to stitch the fabric?” – No I don’t; it will be a fiddly, time consuming job that will add weight but won’t add significantly to the scale appearance. In fact, as I later found out, at this scale and it must be said with my lack of expertise, the rib stitching looked less like the real thing than the simulated stitching.


So, “do I need to stitch the fabric?” – Yes I do; I know many people have no trouble with under cambered wings but I’ve had the covering pull away on a glider and with a model of this complexity it’s just not worth the risk!


I first tried Barry’s idea of three stitches with the rest simulated, this is where I found out that the simulated stitches looked better, I just couldn’t hide the knots. I rejected this method because with the stitches all being in the same position it would have ended up with three rows of different looking stitches running span wise along the wings, which would have looked very obvious.


Next I tried full stitching; as I had predicted very fiddly and time consuming and it didn’t look that good.


In the end I decided to just “wrap” the thread around the ribs without any knots, each stitch fixed with a drop of cyano. I find the easiest way is use a strip of paper with the stitch spacing marked on it placed along side the rib, make a hole in the appropriate position next to the rib using a pin, then use these holes to pass the needle and thread through.





The centre section is fabric covered on the underside and sheeted to the rear spar on the top; before the sheeting is fitted it shows how I’m doing the stitching.

[wonwinglo]

Grahame on reflection I think you have tackled this the right and most practical way,Dave Boddington used to say if you cannot reproduce a method in model form then at least simulate it in some way in order to look convincing,as artists of the art trompf school make things look as if you can touch them by simulating three dimensional effects,so model builders can achieve realism by cheating a little,the secret is to make the eye believe that what you are looking at is in fact real looking.

To this end I think that your model will look realistic at this scale.

Duncan Hutson was the one to do rib stitching on his many Tiger Moth models,not quite sure how he did it but it certainly looked realistic.

[Greyhead]

It’s strange how size affects things; I once built a Hawker Hind, the plan had offset bell cranks that imparted differential aileron to counteract adverse yaw. I modified the plan to incorporate the scale Frise ailerons, which were designed for this problem, only to find out latter that at this size they don’t work. Luckily I’d also used individual aileron servos so it was easy to “dial in” a bit of differential, which solved the problem.

I suppose it could be explained because the model has to fly in “full sized” air but it’s more difficult to explain why something replicated as the full size just doesn’t look right at a smaller scale, such as rib stitching!

The only slight problem I have with the rib stitching is the last stitch at the trailing edge, which has to go through the wood itself because the TE wouldn’t be strong enough at scale dimensions. It’s not really needed so it might end up as a “false” stitch if it proves too difficult / boring when doing all the wing ribs!

[wonwinglo]

Grahame I once test flew a quarter scale Turbulent for someone,it had scale wing slots just as the full sized fixed ones,that flight was the most erratic test flight that I had done,in fact the model became almost uncontrollable and was glad to get her down on the ground.It seems that as you say sometimes things do not work in miniature,as they do normally on the full sized machine,normally as we know scale tailplane areas do not work on our models either and we need to increase the area,with slots and slats the effects can be quite alarming,the thing was this was the Precedent kit which should have ironed out the bugs,how many of these have been built and flown with these problems which were probably not understood by the builder ?

So whilst it is certainly wise to follow the designers build as regards construction ( after all they knew better than ourselves ) this does not always follow with some standard aerodynamic devices or concepts.

I once conducted practical tests with fixed leading edge slots and will elaborate on these some other time.

[Greyhead]

The centre section has had the top ply added and the covering finished. The rib stitching works well and was no problem to do. With the top frayed rib tape added it really looks the part, the under tape, which I’ve never used before, is quite visible and adds a lot to the finished effect.





Frayed tapes are nowhere near as complicated to make as serrated ones but there is a technique.


The Solatex is marked at the correct width, a small nick made with a sharp blade and the strips torn from the sheet; this ensures that the edges follow the material weave. Discard the first strip with only one torn edge; it will most probably be tapered anyway, then make another nick close to the edge and “tease out” a couple of threads, repeat for the other edge and you have a perfect frayed edged rib tape ready for ironing in place.

[wonwinglo]

That looks better than I thought it would work out Grahame,good tip there on fraying the Solartex.

[Greyhead]

I was talking to a friend the other day about the instrument panel; he is also building an SE5a and has a photo which has the instruments in different positions from the one I have. I wonder if perhaps the plane “developed” as a result of reports from pilots about visibility of the instruments whist flying?


He liked the results of my build but said that in his opinion the thread didn’t explain the method fully enough. As I have just started the altimeter here’s a “blow by blow” description; I hope you don’t find it too boring!


I won’t go into the intricacies of Photoshop, but using mainly copy & paste, rotate and distort, the original photo is manipulated to produce an acceptable image with a resolution of 1200 pixels / inch. This is printed on photo paper and glued onto 1/64th ply; you now have to be very patient and wait for the glue and paper to be completely dry.





Cut out, not too close to the image and then sand away all the surrounding material. I use a sanding disc in my Dremel for this but it’s delicate work so be careful and turn the speed to its lowest setting, if you don’t have variable speed it might be advisable to do the last bit by hand. Whichever way you use be sure to always sand downwards away from the dial face, it’s all too easy to delaminate the photo paper.





A cocktail stick and a piece of blue tack make a good holder whilst the edge is painted. Now you have to find or make a suitable ring; a search through the “useful items “ box will often yield a result, in this case the top from an air freshener refill, failing that start from scratch with a piece of Plasticard or similar material.





The ring is now painted and stuck to some acetate using “canopy glue”, which dries transparent, the excess trimmed away and the edge repainted.





All that’s left to do now is to make the adjusting knob, from some plastic sprue, and assemble the parts.





The photo doesn’t show the finished instrument to its best, I just can’t photograph things this small and get the detail to show, but I assure you that once fitted into the cockpit it will look the part.


It seems to have taken longer to do this post than it did to actually make the instrument but I’m sure that’s not really the case!!!

[Greyhead]

With the centre section removed for covering it’s the idea time to wrap the front cabane struts.


First of all the struts are given a coat of Solalac Clearcoat, which I’ve used for years to help the Solatex to stick.





I know the “industry standard” is Balsaloc, which I’ve also used, but in my opinion it’s nowhere near as good. With Clearcoat the Solatex won’t lift but if you do ever want to remove it, a run over the join with the iron and it can be peeled back without lifting the balsa fibres then rejoined as good as new. When the wing spars in my Albatos Dva broke I removed the entire wing covering from both wings, repaired the spars and then replaced the original covering; saved having to do all that paint work again!


It has another advantage in that the Clearcoat and the Solatex adhesive will bond without the use of the iron. It doesn’t “grab” immediately but if held in close contact it sticks after a few hours. This proved very useful for the base of the cabane struts where there is no chance of applying the iron.





I gave the struts a quick blast with the heat gun just to speed up the bond.

[wonwinglo]

Sorry Grahame,I had not realised that you were not aware of the fact that there are at least six different S.E.5A instrument panel layouts,by this I mean original ones and not the scores of replica machines built in recent years.

Just love this rundown on the instrument fabrication,as they say a photograph saves a thousand words,another excellent source of rims for the instruments are small rubber seals obtainable as boxes of assortments in those useful £ pound shops.