Scratch Built SE5a

[Greyhead46]

Hello Rich Griff

 

Sound just the sort of thing I hoard; you never know when or even if you'll need them but if you do and you saved them you've got them if you " binned" them you've not!

 

Grahame

 

 

With the decking finished I had the problem of filling around the cabane struts and bracing wires. It is only 1/32nd thick so the filler itself will have no strength and the rear face is a complex shape with the tubes etc. passing through the curved decking so any backing would be quite difficult to produce accurately. I then remembered about “Micropore” surgical tape and cyano; the tape is self-adhesive and followed the shapes easily, once in position a few drops of cyano turned it into a solid backing. With a couple of pieces of ply to form an edge it’s ready for the lightweight filler.



It took a few applications of filler to get to this state ready for covering; I’ll give it a few drops of cyano to harden the filler before I cover it.

 

The final decking is just 1 layer of 1/64th ply and the stringers, except the centre one, have been removed to save weight. Small savings behind the CG really do make a difference; the further aft the greater the effect.

 

The top of the fuselage is covered in 2 pieces, first all the decking and then the stringers to just behind the cockpit, so the rear decking has 2 layers of Solatex. If I say that covering the decking was a challenge you’ll get the idea, I certainly envied the full size where the struts and bracing wires are removed before covering.

 

The decking is in 3 sections with one of the joints just aft of the cockpit at the “break” point; this would seem to be the place to end the decking covering but it would create an obvious weak point so the covering is taken back to the end of the decking. The “stringer” covering is taken forward over the decking because the decking is a different length on either side of the fuselage. Done this way there is a neat join between the coverings, which is further strengthened by a frayed tape.

A little extra weight but I wouldn’t want the decking to “spring” open on a less than perfect landing; where strength isn’t an issue I save every gram I can but there’s no point building so light that you’re for ever having to repair the model.

I’m now ready to start on the next section, the fin, skid and rudder but before I do I compare the actual model to the plan. This is for 2 reasons, firstly the plan is amended for those things that didn’t work out exactly as I’d envisaged and secondly it ensures that the next bit will fit what has already been made.

 

Edited March 20, 2023 by Greyhead46

[Greyhead46]

Before I start on the construction of the fin itself I want to be sure that the tail plane incidence adjuster will work so I’ve made that first.

The fin post is a carbon fibre tube through which the adjuster rod, a snake inner, slides; the 2 attachments for the bracing wires are made from closed loop adapters and brass wire.



The lower attachment has a 2mm cap head bolt that will do the actual adjustment by screwing in or out of a length of snake inner firmly fixed to the fin post; I used snake inner for this as it acts like a large “Nyloc” nut so won’t alter the incidence as a result of engine vibration.

Any adjustment required will be made using an Allen key through a small hole in the base of the tailskid fairing.



This is the position it will be fitted in, at this setting the adjustment is about central and can be altered approximately 7mm either way.

 

The fin is made using “core and half ribs”; for those not familiar with the method it is a simple way to make strong but light structures, especially if the outline is “curvy”. It is my preferred method even for simple shapes such as the SE5a fin, rudder and elevators; the tail plane may have to be a fully built up construction because of the cable and pulley elevator linkage, I’m not decided as yet.



To start the core is cut to the shape of the finished item, the usual material is 1/16th balsa but I’ve heard of the use of thin ply for extra strength or even Depron if weight is an issue. The positions for ribs etc. are marked then one side constructed whilst the core is pinned to the building board, thus ensuring a straight structure. After leaving plenty of time for the glue to fully dry the process is repeated for the other side.

 

[Greyhead46]

The rudder uses the same method of construction. There’s no separate trailing edge, the core itself does that job; the covering is fastened purely to the edge of the 1/16th core, this works OK because all the edges are eventually taped.

 

The top and bottom edges have 1/8th x 1/16th balsa added. The balsa is soaked in ammonia for a couple of hours, the pieces for the other side are soaking in the plastic tube, the inner edge is pressed with the back of the scalpel blade to help it bend then it is pinned in place and allowed to dry before gluing.



With the lightening holes cut and the edges sanded all that’s left is the hard points for the hinges and that’s another problem.



I’ll have to make my own hinges to go around the tail incidence adjuster; I could use a commercial hinge for the top but then they wouldn’t match. If I’ve got to work out how to make one I might as well make them all, including the elevator and aileron hinges, happy days!

 

As the build progresses I’m always thinking in advance, sometimes many months in advance, and one thing that has occupied my mind for a while now is whether or not I should make the tailskid steerable. From a purely practical point of view it isn’t necessary as it is only really used whilst taxiing, on the take-off run the rudder is effective enough on its own. It is also more complicated, with hinges and linkages to organise, not to mention the extra weight, so all things considered I decided against it.

The problem was I was thinking about it “in isolation”; now I’ve come to actually designing the part it is obvious that because of the tail plane incidence adjuster the skid has got to be separate from the front section and will need some substantial fixings, so they might as well be hinges. The best laid plans of mice and men etc.



The construction is a variation on the core method; in this case the core is a 1/16th ply frame with tongues to locate it in the fuselage, 1/16th ply doublers at the rear where the hinges will fit and 1/16th balsa sides.

 

The tailskid is made from 1/8th ply with the hinges from brass tube and strip. To avoid the dreaded “metal to metal contact” the hinge pin is a snake with the outer attached using the time-honoured method of stitching with button thread. The top hinge has a washer soldered to it to act as a bearing



Here it is temporarily in position.



The tailskid shroud will be from litho plate and will hide the stitching.

With a steerable tailskid there may well some taxiing going on

[Geoff S]

Does the incidence adjustment alter the empennage as a whole - ie rudder/fin and tailplane/elevator?

 

More fascinating insights as to what thoughts go into the design and build of a scale model.

[Greyhead46]

Hello Geoff

 

It only adjusts the tailplane / elevator incidence.

 

The tailplane is only attached to the fuselage by the main spar, which acts as a pivot, and 8 rigging wires, 2 top and 2 bottom for each tailplane half.

 

The front wires attach from the front spar point to the fin (top) and skid (bottom), the rear from the trailing edge to the top and bottom adjuster attachments. This photo of the finished model shows what I mean.

 

 

In practice I’ve not had to adjust the incidence but if the adjuster is moved up or down the tailplane incidence is changed. With the front wires being attached almost at the pivot point (only half the thickness of the tailplane away) there is no noticeable change. On the full size of course the rigging wires have turnbuckles.

 

Grahame

[Greyhead46]

If you’ve read this thread from the beginning then you’ll know that I have been giving some thought as to how to make the control horns, which are quite thin; with the tailskid being steerable now is the time to put the thoughts into practice.

Thin steel is really the only option for the horn itself but attaching the cable to it is the problem, a standard clevis would be way too big and a cable passing through a hole would quite quickly be worn through. I hope I’ve solved the problem by bending a “yoke” from thin brass rod.



A thin brass pin goes through the hole in the horn, it’s peened over at the ends and finally the whole lot is soldered to the horn so that the pin isn’t taking the load. The only problem I can see with this is that the attachment point is slightly in front of the horn but I can get around this but slightly altering the angle of the horn and mounting it slightly to the rear.

The skid has a balsa TE extension and is then shaped with lightweight filler where the litho plate shroud will go.



The control is transferred from the horn to the skid via a thin pin to give the servo some “shock protection”, I might also use springs in the cables but from past experience I find these tend to make the steering a bit erratic.

With the shroud fitted that’s the skid virtually finished.

[Greyhead46]

The hinge is a short length of brass tube soldered to a brass strip, which goes around the tube as a safety measure in case the solder joint fails. The pin is 22 swg piano wire and will have a brass “keeper” soldered behind the rudder LE when in position.



The rudder is recessed to allow the hinge line to be central to the radius of the LE which has additional strengtheners added.



The hinges are riveted to the fin TE using brass tube, given a final drop of cyano to securely lock them in place then faired in with some 1/32nd balsa.

As I explained earlier, at this scale “true” rib stitching doesn’t look as good as simulated in my opinion; for the wings I used a compromise which holds the covering to the under camber but looks OK but I can’t use this method for the fin and rudder because of the thin section and the core method of construction.

To simulate the rib stitching a simple jig makes life a lot easier. The thread, I’ve used brown here to show up, is laced around the pins, which are set to the correct spacing, and over the top of the Solatex; to hold them in place I use a tiny drop of thin cyano then give the whole lot a coat of Clearcoat.



Thin strips are cut and tacked in position over the ribs and when the top frayed rib tape is ironed on it bonds everything together. The finished rib tape looks near enough like the real thing for me!



I should have been more careful with the heat gun when shrinking the LE tape around the top of the fin because the covering has pulled back from the TE, but it doesn’t really matter as there will eventually be a litho plate cover running down the length of the TE.

 

[Greyhead46]

When finishing the fin / rudder assembly I turned up the heat on the iron to shrink the edge tape around the curves, with the covering only attached to the 1/16th edge of the rudder I couldn’t afford any shrink back as happened on the fin. The litho plate shroud conveniently covers that fault and really finishes it off; the hinges and incidence adjuster now look the part.



Incidentally the tapes on the rudder are in fact parallel, for some reason they just look that way on the photo.

·          

The tail plane presents several problems, not the least of which is how to operate the elevators. I prefer to use the same method as the full size aircraft even if this is quite complex, as with the Elf; in that case the linkages were external so easy to check and maintain, but I have reluctantly decided that using the scale closed loop system is not practical for the SE5a tail plane, I still intend to use it for the ailerons. With the rear of the fuselage being open I should be able to hide the non-scale linkage.

The main spar, made from 4mm carbon fibre tube, will have a piano wire pin into the fuselage held by a grub screw similar to the wing fixing; it also acts as a pivot point for the variable incidence. I’ve also used a carbon fibre tube for the TE; this is short because the tail plane tapers towards the tip.



The ribs are cut long so there is sufficient strength around the hole for the carbon fibre TE during construction and are trimmed back later for the addition of a 1/64th ply facing.

Here’s a photo of one half, complete with piano wire pin, ready for the hinges and bracing wire hard points.



The tail is 2 separate units so I’ll connect them with a short length of carbon fibre slid into each TE to ensure that any adjustment to the incidence is equal both sides.

 

I’ve used the simple but effective core method for the elevators. With hindsight I shouldn’t have cut the lightening holes in the 2 outer bays; because the tail plane tapers down to just 1/16" at the tips there is very little strength left.



I’ve added some carbon fibre tows, which help. The carbon fibre TE joiner is only glued on one side to allow the 2 piano wire pins to slide into hard wood blocks in the fuselage, which are then held in position by 2 bolts tightened through holes in the bottom. If I can find a 0.9mm Allen key long enough I’ll replace the bolts with grub screws; I might have a go at extending the one I’ve already got.

 

Finally a photo of the finished tailskid in position which also shows the lower incidence adjuster attachment.



For practicality I’m going to bolt it in position, this will mean that I’ll be able to easily remove the skid, fin / rudder and tail plane halves from the fuselage if it becomes necessary. Once everything has been thoroughly tested and proven, then I may attach the skid permanently as per full size.

Edited March 23, 2023 by Greyhead46

[Andy J]

Grehead46, out of interest are the ribs and other parts cut with a laser or by other means as all your balsa parts appear to have very sharp profiles and are obviously precisely cut.

 

Continue to watch this thread with great interest as it is a true master class.

[Greyhead46]

Hello Andy J

 

Thanks for the reply; There's no high tech with me, just a fine draftsman's pen and a good old scalpel, works for me so long as the blade is changed regularly well before it dulls.

 

Grahame

 

 

 

I’m not sure whether this is the third or fourth version of the control pulleys but they are now at a stage of development that I feel warrants a trial. The problems that have arisen during tests have been the pulley wheel jamming and the cable jumping out of the groove in the wheel if there was any slack in the system.

Here is a photo of the new components and a finished assembly.



The jamming has been cured by using a larger diameter bush in the wheel and an extra length of tube slightly longer than the thickness of the wheel through which the pin goes; this ensures that the wheel doesn’t bind on the shackle when the pin is peened in position. The extra “arms” on the shackle are bent around the edge of the wheel to prevent the cable jumping from the groove.

 

Having made 2 pulley assemblies I decided to trial fit them in one half of the tail plane before making the rest. Fitted temporarily and using button thread for the cables has proved that the pulleys are OK but that my calculations for the height of the elevator horns were wrong; they need to be 2mm taller to prevent the cables catching on the covering support.



The final cable runs will all be through the ribs but at this stage it’s just easier to leave them on the outside.

 

I was talking to a friend about the elevator controls and he wondered why I wasn’t going to use the scale system for the elevators, but was for the ailerons, especially as I’d gone to all the trouble of making working pulleys; so here’s the explanation:

The pulleys have to be incorporated anyway because they are a very “visible” part of the model, but the problem is getting the control cables into the fuselage in such a way as to be useable. If I’d designed the tail plane as a one-piece unit it may have been practical but it just wouldn’t look right and making the tail incidence adjustable would then have been impossible without having gaping holes in the side of the fuselage. With the aileron linkage there’s a lot more room and only one cable per side, which can be attached directly to a servo, should be no problem (famous last words!!).

 

The elevator control pulleys work far better now that they have their solid attachments and the tubes for the cable runs. The tubes are free if you’re lucky; they are what lengths of piano wire are in when they are delivered to your local model shop and are usually thrown away.

 

In fact they work so well with the cables connected, at the moment only using button thread, that I’m wondering if it may be possible to actually use them for the elevator control. I’ll get them covered and leave the decision till later; it’ll involve some quite major “surgery” to the rear of the fuselage but if at all possible it will be worth the extra effort.



Here’s a photo of the tail plane in position; the elevators have already been covered.



I have usually covered my models with white Solatex as I find that any colour paint produces a good solid cover over it, but for the SE5a I’m using natural as the underside is plain, doped linen. When I covered the fin and rudder I used scraps of white Solatex for the rib tapes, but for the elevators I used the same Solatex that I’m using for the main covering and this was when I discovered that it is so much easier the fray the natural Solatex.

If you are building a WW1 model and you’re going to fit rib tapes I strongly suggest that you use natural Solatex even if it’s not the best match for your paint, it really is that much easier!

 

Edited March 24, 2023 by Greyhead46

[Murat Kece 1]

the neat details are excellent...👏

[Greyhead46]

Hello Murat

 

Thanks for the reply, glad to hear you're finding it interesting.

 

Grahame

 

My original thoughts on the elevator control were that the 4 cables would have to run forward to a servo, or more probably a “slave” bell crank, just behind the cockpit. This would involve 4 extra pulleys mounted behind the tail plane fixing block, therefore the cables would have to exit the tail plane at least the diameter of the pulleys plus half the thickness of the fixing block behind the pivot point. This in turn means that if the tail plane incidence needed to be changed, almost a certainty, the cables would move through a considerable distance so the pulley fixings would have to be able to accommodate this; all very complicated and therefore most likely unreliable. Not the sort of thing you want in such a vital system so I decided against!

As I took the photos, for the previous post, of the pulleys with the cables in place I held them tight with my finger and thumb; this is when I had a “eureka” moment, if I twisted my finger the elevators moved!



My idea now is to use a horizontal drum mounted close behind the fixing block with one cable going from the top horn of one elevator, a complete turn around the drum to the bottom horn of the other elevator; a “slave” cable will join the other horns together to transfer the pull.

 

Well having spent a couple of days with the tail plane on a jig experimenting with various pulleys, drums and bell cranks it’s back to plan A!! The problem in the end was not the pulleys etc. but being unable to get the correct and equal tension in all the cables. The aileron controls will have an adjustable “quick link” where each wing joins the centre sections but with the tail plane there just isn’t the space.

The elevators will actually be moved via a snake and ball link, which will be pretty much hidden inside the rear of the fuselage.

The cables go straight from one side of the tail plane to the other and are for “effect” only but look quite convincing; these photos show the final trial set up on the jig.

[Greyhead46]

The attachment points for the tail plane bracing wires are not bolted on from the outside but attached internally and they are substantial items that exit the structure at acute angles, which would make covering after fitting quite awkward. To get around this problem I incorporated brass tubes into the TE and spar, after covering I passed a brass rod through the tube, soldered the attachment lugs to it and then bent it to the required angle; at this point the attachments were actually free to rotate. To check the angles were correct, and alter the ones that weren’t, before finally fixing them with a drop of cyano I rigged the tail plane using cotton.



Although C1096, upon which I’ve based the build so far, doesn’t have a headrest my model will as I think it is a quintessential part of the SE5a. First a frame from 1/16th balsa and 1/32nd balsa skin.



Then cover with litho plate.



Finally glue in position.



Once the glue’s set I’ll add the frayed tapes over the joints; she’s looking more like an SE5a every day.

[Geoff S]

I think the shape of the fin/rudder (and the two wings!) alone make it look an SE5a.  Heck, even my Flair version I built over 20 years ago looks quite a lot like one with far fewer scale detailing features 🙂

 

Love the dodge-round for elevator operation whilst fooling an onlooker that pulleys are doing the work.

[Greyhead46]

Hello Geoff

 

Once they're in the air most scale detail is lost and the basic "plan view" is what matters.

 

My old Albatross (first attempt at "own design") had very little detail but still looked the part when flying, but I got the bug and each successive model has had more and more detailing!

 

 

Grahame

[Greyhead46]

Now for the Vickers machine gun; about ½ the barrel protrudes from the gun cover and only the rear and right hand side of the stock is visible but I’ve decided to build a complete unit. The extra weight will be negligible and in the event of an untimely end to the SE5a it may be salvageable as a useful item.

The barrel cover is 1/64th ply, soaked with ammonia and bent around 1/32nd ply formers that are temporarily mounted on piano wire to keep things aligned.



The outer skin is litho plate embossed using an old ballpoint pen with the louvers cut and eased out using a scalpel.



The barrel is aluminium tube and the flash suppressor plastic. The whole lot is painted matt black.

 

The trick now is to take a soft pencil, I used a 9b but anything from 4b upwards is OK, and scrape the “lead” to make some graphite dust, apply this and then carefully burnish with a lint free rag. The resulting finish is a perfect “gunmetal”.

 

Here are the basic parts for the stock; the sides are 1/64th ply and the core ¼” balsa.



The “eject side” has an 1/8th lite ply spring cover. You can see the rivets, which were embossed from the reverse side using an old ballpoint pen as for litho plate

 

The ammo feed shoot is aluminium



It now needs 3 coats of sanding sealer and painting before adding the various levers.

 

The top covers are from litho plate but the levers need more strength so are cut from a “bean tin”.



The “eject side” having had the matt black and graphite treatment, which really brings out the rivet detail. The extension at the rear is the connection from the interrupt system and will have a copper pipe attached

 

The levers are pivoted using cut down pins and a 14BA nut and bolt, the handle is stained spruce.



Here are a couple of photos of the finished article.

 

An added bonus is the fact that it was built entirely from the “scrap box”, they don’t come much cheaper than that!

[Greyhead46]

Because the Vickers takes up most of the space under the gun cover a built up structure is impractical and the cover itself can only be thin so I decided to use my least favourite modelling technique; a fibreglass moulding.

For a “one off” I won’t bother making a female mould so first a slightly undersized balsa plug is made, using the piece of decking I removed as a base, filled and sanded smooth.



The plug is then covered with cling film; a useful thing about cling film is that it is in fact to some degree heat shrinkable so it’s relatively easy to get it to conform to the double curves. Then the first layer of glass cloth and resin is added, the only glass cloth I have is very lightweight “wing skinning” woven mat, so several layers will be needed to build up the strength.



Whilst waiting for the resin to cure I remembered that a few years ago my brother give me an off cut of coarse carbon fibre matting, quite loose woven so ideal for forming around double curves, just one layer of this should be sufficient. But finding it was no easy task; somehow it had managed to fall down the back of the shelf, fold itself in half and hide behind a cardboard box, if it had stayed where it was put I’d have seen it when I got the fibreglass cloth out and saved myself a lot of trouble!

The fibreglass was removed and replaced with carbon fibre.



Don’t ask me why I didn’t just leave the original fibreglass in place and put the carbon fibre over the top; I put it down to euphoria about not having to do all those extra layers and too much Christmas spirit (most probably in the reverse order!!).

After leaving to cure overnight the edges are trimmed, the front cut away and the slot for the cabane bracing wire cut. I’ve used carbon fibre tows to put 3 “ribs” on the inside to really stiffen the whole lot up.



Finally a shot of the Vickers in position showing just how little in actual fact is visible from the outside; the stock is partially visible viewed via the cockpit opening and the inspection hatch.

[Geoff S]

You've inspired me to have a go at making the Spandau guns for my Fokker D-VIII.  They're totally exposed, unlike the SE5a, so the extra detail will be seen.

[john stones 1 - Moderator]

Love  it. 🙂

[Greyhead46]

Thanks for the replies.

 

Just be careful Geoff you might catch the "scale detailing" bug, it's very infectious and like Covid can be long term! Seriously though, this is just want I hoped for with this thread and I guarantee you'll get more satisfaction than assembling a plastic kit. Hope you'll post some photos.

 

Grahame

 

One coat of resin was enough to give the required strength but being quite a loose weave meant that it needed a lot of filling but to me this was preferable to working with resin to add extra layers. I can’t say that I’ve really enjoyed this part of the build; from now on it will be OK but it started badly, I think as much as anything because I had the wrong attitude, I knew I wasn’t going to like it and that’s not the way to start things. There are a few more small mouldings needed for the SE5a and for these I’ll certainly try out the brown paper technique first and start with a positive attitude!

The inside of the cover.



The resulting finish will be smooth enough to simulate metal so no need to cover it with litho plate, this is with just one coat of silver Solalac and not yet sanded.



The next job is to make the 2 long “hinges” that attach the cover to the fuselage, they have loose pins, so the cover will be removable but not easily. Once again these are not working hinges, when the model has been painted etc and the cover fitted in place it shouldn’t have to be taken off again (unless I want to show off the Vickers!) so litho plate will suffice.

Here’s a series of photos showing the method of making a hinge.

The litho plate “blank”



The first bends.



The second bends.



Bent around the hinge pin ready for trimming.



The assembled hinge glued to the cover.



When gluing hinges like this it’s obviously important to not glue the pin so use very little epoxy to “tack” the assembled hinge in place, take it apart and fill in any voids with more epoxy. The same applies when gluing to the fuselage.

[Geoff S]

Another way to produce non-stressed sheet parts is to use papier mache.  I needed a lightweight tube to guide my screwdriver to a buried wing bolt and made it out of newspaper and white glue round a convenient piece of tube (aluminium, I think, but anything will do provided you wrap it in (say) cling film). It was both very light and surprisingly robust.  I hadn't tried since I made a glove puppet head at junior school 70 odd years ago 🙂

[Greyhead46]

Hello Geoff

 

I remember it well except mine was a pig fashioned around a balloon!

 

Grahame

 

Some SE5a’s had an extra hatch towards the rear of the cover; I think I’ll add one to take away the plainness. With the bracing wire passing through the cover and the angle of the top “hinge” I didn’t think that it would actually work as such and would really just be used to hold the cover in place, but in fact it does allow the cover to be easily hinged open, I should have had more faith in the designer! Of course now I need to make a convincing mount for the Vickers, as I will be able to “show it off”.

With the extra hatch and the other various fittings added the cover is looking a lot more business like.



With the cover hinged open the Vickers is visible in all its glory.

[Greyhead46]

Here’s a “quick build”. It’s the oil reservoir for the interrupt gear; simply a plastic tube with a carved spruce handle and plasticard supports painted all over gloss black.



It is attached below the instrument panel and points forwards into the foot well. At the moment it’s full length but because of the way it fits it may interfere with the servos so I won’t actually glue it in place as yet. If necessary it will have to be shortened.

 

While the better half hit the sales I visited the model shop and bought the copper tube for the interrupt pipe and the snakes etc. for the elevator. I’ve now managed to “fix” the positions for the servos and therefore the interrupt reservoir; it didn’t need shortening.

Here’s a “pilot’s eye” view of the completed cockpit. Not much of the Vickers or the interrupt reservoir showing from this angle!

[Greyhead46]

I’m always amazed at the number of models that seem to have had the radio gear added as an afterthought, decent models spoiled by a row of servos bang in the middle of the cockpit. I’m sure with a bit of forethought they could be mounted more unobtrusively and for the last few days I’ve been busy mounting the servos for the rudder and elevator; not the most “glamorous” of building jobs and as such it doesn’t make for a very exciting post, but nevertheless very important; for the moment the control cables are button thread.

What might be of interest is the linkage for the rudder / tailskid; the rudder servo arm has two 2mm bolts / nuts, the “quick links” are cut away to stop them fouling at maximum deflection.



The tailskid servo arm has it’s splined boss removed and is fitted on top of the rudder servo arm by the two bolts. The control cables are connected by piano wire links incorporating a “Z” bend to provide some shock resistance

 

This photo shows the double-decker arrangement more clearly.




Another thing that perhaps I should point out is that the front servo rail isn’t glued but fixed to the side rails by 2 servo screws. I find it quite awkward feeding servos between fixed rails, especially in the cramped interior of a model, so being able to slide one of the rails to widen the gap is very helpful.

When looking at one of my previous servo installations a fellow modeller pointed out that he wouldn’t be happy with 3 servos effectively held by just 2 screws. Well I’ve used this method for quite some time and had no problems; there’s no way the screws would sheer before the rail itself broke and routine maintenance ensures that the screws are always tight

[Greyhead46]

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!

 

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.