1/24 scale DH Mosquito for rubber power.

[Kelly]

Fantastic work as usual JohnStephen!

Sorry about that.

[Prosper]

No need to apologise Mike - at least to me . . . John might be offended though, being mistaken for me .

. . . For me it's a critical part of the plane's look.

Definitely. That's what I've always thought too.

I've just glued the fuselage sections together, for better or for worse. What is seen here weighs 9.3g - that would be 8g without the pendulum.

Stephen.

[OZPAF]

No need to apologise Mike - at least to me . . . John might be offended though, being mistaken for me .

No worries  Just feeling a little crossed out  

John

[Prosper]

Now there are many odd jobs to be done.

Fairing the nacelles and the wing: I made soft balsa fairings stuck to the nacelle. Big misgivings, because these may make it impossible for me to tissue-cover the nacelle. I'm doubtful enough that I've only done this fairing on one nacelle, and I've used UHU glue for easy removal of the fairings if necessary. There is a list of things which I'm sure I'll have to add after covering; these are the bomb bay fairings front and rear; the carb air intakes under the nacelles; the wing-top fairings behind the firewalls, and sundry little lumps and bumps.

Fairing wing/fuselage: the fus. sides are curved and the wing root ribs are flat - hence a gap. More soft balsa padding I expect.

I got the angle of the nacelle front formers wrong. I've added wedges to the top half and sanded away the three-ply below this, to provide a new face at the correct angle. Thankfully the 3-ply is thick and strong so can take some reduction. I think what I did was to install the formers perpendicular to the nacelle datum - but the nacelles are canted up a good bit relative to the fuselage datum. I must have known this, having built the test model, after all . . . Old age, I expect.

[Prosper]

The ailerons. Long fiddly job of final instalment. As of now there's a very narrow gap (arrowed) between the aileron and the wing. One wants this, to look scale, but even the slightest binding is not tolerable (and with gaps this narrow even the thickness of tissue covering may be relevant). So, much fine-tuning is called for. The Frise ailerons have their rigidity provided by an 'L' section spar/leading edge of quite hard 0.8mm balsa. I've had problems in the past with ailerons warping fractionally - enough to cause binding - and these are the longest I've ever made, so need special consideration.

Stephen.

[Crabby]

Incredible amount of thought and care you put into your projects. I find it to motivate me back to my own projects whether they be at my modeling environment or about the house. I ask myself how would Prosper handle this? Not that  my Crabbifications haven't taken me far.Reading your posts are like taking supplemental vitamins. I am in great hands here. We have had some great craftsmen on this site. "Modeling Maniac" is a term of endearment not a criticism.

[Prosper]

Crabby, just in case it wasn't clear, my 'ranting' about not being a modelling maniac in post #118 was a joke. Of course I am one - albeit one who doesn't very often use 'emoticons' to make things clear - because he selfishly assumes everyone will understand that here he's being sarcastic . . . there mischievous . . .  there snarky . . . sincere, whatever. This is where 'emoticons' are useful, because there's lots lost in translation even between English-speaking nations. Not that Americans can speak English of course . . . Oh no! there I go again! [quick edit]

Yesterday I finished fitting the ailerons. Today I turned to the 'front ends': the props, freewheels and associated ironmongery.

Pic 1) shows making brass bushes, just over 4mm long. After years of anguish where I had to drill and ream brass tube to fit 1.2mm propshafts (such a sloo-oow and messy process), some kind soul (sorry - forgotten who) on HPA2 pointed me to a model shop selling 1.2mm I.D. brass tube. I approached with caution, because in the past I had tried different tubes which vendors claimed were a match, only to find jamming or rattling around loosely. All this comes from S.W.G vs. Imperial vs. metric, I think. Anyway the tubes from that shop (Leeds Model Shop IIRC) fit my 1.2mm piano wire perfectly - no binding but undetectable play.

What I do is to use a length of 'sacrificial' piano wire as a handle, and use a hacksaw blade to part the lengths of brass (with a thumbnail as a guide for the blade). The hacksaw blade gets thru to the wire, then I rotate the tube slightly and continue; the  sawblade is now guided by its own cut, until it meets its original cut having gone round 360°. The brass isn't fully cut through usually - the tube is slid off the wire, the bush is snapped off the longer tube, and the ends filed and sanded square. I wish I could find a saw - rigid, with loads of teeth-per-inch, somewhere halfway between a razor saw and hacksaw. I call the wire sacrificial because this work leaves it scored and scraped by the saw - not much good for anything after that.

Pic 2) bending 1.2mm piano wire round a wire post to create a radius. When I started modelling I bent hooks with needle-nose pliers. Occasionally I'd get catastrophic failures where all strands of a motor snapped at the hook. I saw that people use various plastic sleevings. This didn't seem to make much sense to me - I'd already established that rubber can stretch round small radiuses to ridiculous lengths before failing. I had inherited a simple hobby microscope. I looked at one of my diamond hooks, bent using pliers - and at about only 10x magnification, I could see that the inside of the bend was fractured with several tiny splits and slivers of metal - all with extremely sharp edges. Since then I always bend hooks round a generous radius: never had a break at the hook since.

Pic 3) the four bits of wire in the previous pic are filed half-through for part of their length: I'm afraid the pic doesn't show this at all well but perhaps the filed flats are visible.

Pic 4) shows the finished result. Two bent bits of wire are pressed together where the flats are; a collar of brass tube is run up them keeping them snugged together; the whole lot is brushed with solvent for degreasing; some solder flux paste, and bingo they're soldered together into a T-hook.

N.B. This sounds easy, but any of these steps can be a bit hit-or-miss. Take the filing half-through the wire - if not enough the brass collar or collet won't fit, or if the flat isn't perpendicular to the cross of the 'T' the hook will be wonky, etc. etc.. In fact the examples shown are far from the best I've made. I think they're good enough to serve, though. To finish, the ends of the 'T's are filed round to remove sharp edges from their having been clipped.

[Prosper]

Pic 5) oh no - more bent wire using my trusty oak block. These hoops are 0.8mm wire.

Pic 6) oh no more  bent wire using my trusty oak block. These coils are of 0.6mm wire wound around a 0.8m post.

Next comes the spinners and nosecones. Thru all of this build there has been the temptation to nick items from my test model - mostly metalwork like this, and pendulum parts. But that model hasn't done its work yet. With flying suspended because no field to fly on, it still has to pave the way trimming-wise before I fly this model. Also the 'front ends' especially are rather shoddy because it's only a rough test model.

Stephen.

[Crabby]

Ok Professor I am back to sitting in the peanut gallery watching this contraption of yours un-fold. Every little piece seems to be a model. This plane is a hundred models in one.

[Konrad]

Love the master class in wire work, particularly the fixturing used.

These details are often the Ahha moments I'm often missing when trying to figure out how folks make better components than I.

[Prosper]

I'm glad you're interested fellas. Really, I just 'muddle through', as we Brits are supposed to do.

I'm aware of having posted about making spinners, prop blades etc. fairly recently - but I think it must have been in HPA2, so I'll carry on regardless.

When turning things in my super-hi accuracy lathe busted old electric drill (the bearings are shot; the chuck is worn and clumsy), I use laminations of 0.8mm balsa, because I saw when doing this for the first times, that the thinner the laminations, the more concentric the result was. Boy, these spinners need lots of laminations. I draw a grid of different-sized squares on 0.8mm sheet (in this case, 12 off 38mm, 8 off 34mm . . . so on to the small squares that make the front of the turnings. Then I draw diagonals across the squares to mark the centre spot . . . doing this en bloc is reasonably quick: the squares can be cut out with long cuts too - not each square independently. I didn't photograph this, but the pisture attached - of a few remaining squares - gives the idea. The two spinners use nearly a whole sheet of 36" x 4" balsa!

Then I selected a suitable spindle from my little collection - the long bolt on the right, with its nuts and washers. But keep an eye on that one that's arrowed, skulking in the crowd. I offset all the squares, so their grain direction varies. I probably ought to set each square at 90°to its neighbour, but my random method seems to work and is easier. At this point I discovered how hard the wood I'd chosen is. V. hard. Normally I start turning in the drill, but the wood is so hard that in this case I sawed off some of the corners and used 60 grit sanding block to attack the work and reduce it somewhat before putting it in the drill.

The turning in the drill went fairly quickly. There's only a fraction of the total dust produced in the attached pic. I use the drill on a low rpm setting, in reverse (to prevent the spindle nut from unscrewing itself).

[Prosper]

Once the spinner seemed acceptable in terms of shape, I gave it a generous drink of thin CA - the end-grain balsa really soaks the CA up). Then back in the drill for more sanding (outdoors - the CA dust isn't good to breathe). Repeat; and there's the spinner, except for the tip.

The inside has to be hollowed out. The spindle is turned round so that it extends from the front of the workpiece. I use a specific diamond file as the tool to do this job - only in this case the wood is so hard that it bent the tip of the file. It's bad enough, all the snatching and jerking of the tool, which could gore the spinner, or my hand - but now it breaks. (The bent tip is just visible, bottom of picture.) I resorted to removing the spinner from the drill and carving the wood out using a scalpel.

The thickness of the spinner forward of that blue-coloured lamination is only 4mm. The unthreaded shank of the long bolt is longer than that, and that's where the short bolt comes in handy - it has the same diameter and thread as the long one.

[Prosper]

This last pic shows where I got to today. Another session is required: when finished, the rim of the spinner should be only 1mm or so wide. I may have time for another go later.

Stephen.

[Crabby]

Great finding on the thin laminations. I failed several times on my spinners for my Piper Chieftain twin. Still wobbly but I insisted on using block. Next time no excuse.

" we must muddley do
What we doodley do
til we bodily bust" Kurt V.
It's a diddy I hum or whistle as I work

I hope you get use of it. Thanks professor!

[AndyB]

I'm amazed at how you're building this!