greggles.w

Hello all, another notch forward, this time it's the tail feathers. The kit horizontal stabilisers have squared-off joining faces, which do not match the tapering curve of the rear fuselage. I don't have definitive plans to measure against, but it seems to me the kit parts also have some excess at that end with the intent that they can be ground down to suit ... at least this is what I elected to do. A little bit of cardboard scaffolding to suspend the parts in place ... ... which allowed for a 'bendy rule' strip nestled into the curve of the junction as above, so an offset line could be marked. Top left below shows that discrepancy between the squared of part ends & the extent of curve that they need to interface with. Excess ground off (bottom left) then a thin sheet of styrene rolled into the curve for the fairing, drilling & embedding of brass fixing pins ... After that, back in the jig to fix in place ... A little bit of pressure needed to get the styrene fairing to follow the curves. There's still a bit of gap filling to be done to finalise the works. Full disclosure - I suspect these could be more accurately mounted a little further aft, and I think the relative proportions of horizontal to vertical fins may not be true. However in the absence of definitive detailed drawings I elected to settle for a compromise that utilised the kit parts & best suited my subjective eye. That cowling & canopy have eaten up my scratchbuild budget for this project!! All the control surfaces had panel lines re-scribed too. So the list of 'outdoors' tasks remaining is getting very short now!

A most enjoyable & comprehensive read! That said, it is an unfortunate cause-for-pause to bring things to an intermission. I do understand the sentiment, I dropped & damaged my Auster Autocar fuselage - worked on for many months - just as I was applying what I believed would be the penultimate coat of primer. My reaction was just as yours - back in the box for you!! I have only recently had enough emotional detachment to let me pull it out & start repairs, several months later! I have a Dora Wings Vega Gull underway (yes, yes, I know, I know) & have similarly been intrigued & impressed by the kit’s thoughtful parts breakdown. Though I too have tinkered a bit with the intent. Glad to have belatedly discovered this one, now following along. ps, not sure if you inflict F’Book on yourself, but if so, then you may be interested in this group … https://m.facebook.com/groups/1028631820490934/

Thanks David, Ian, Terry - nice to share the madness! While waiting for putty to cure I made a start on the cockpit, first task being to address the monumentally thick (+2mm!) resin slab sides (top left below). So I rigged another 'bendy rule' guide thingy from layers of thin & flexible styrene, that fixed with a bit of double-sided tape to the outer fuselage (bottom left below). This gave a consistent offset thickness which guided scribing down into the top edge. I then ran a drafting pen nib along this groove to flood it with ink, followed by a light sand across the top to leave guide lines ... Thereafter much grinding & sanding & removing bulk from the inside out, up to & including the thickness of the line until the black disappeared & the cockpit tub sloshed with a resin-dust slurry ... That looks a bit more plausible! A little nose bridgework done since last update & cowling top plate added - with inset edges to house canopy. Floor to be added to cover that mess. Now @Courageous Stuart, as you identified, the principle elements to fill this cockpit tub - now with additional shoulder room - are the pilots! Meet Giorgio Parodi & Sig. Frassinelli. I've not found much - not even first name - on Frassinelli down the back there, but Parodi up front was just the type of swashbuckling Golden Era sports pilot we like! Amongst other things he was a founding partner of a motorcycle company in the interwar period, one that took the name of his business partner, a certain Mr (Moto) Guzzi!! Parodi flew in both world wars, in the latter flying Breda & Stukas, and lived on into the 1960's. Not so easy to find suitable pilot figures for this era. We of course need the distinctive flying helmet & goggles, but without all the WWII clutter of integral headphones, oxygen masks, lifejackets etc etc .. even shoulder seatbelt straps seem superfluous for many racers of this period. After much fruitless searching, my go-to for a pilot of this era are from this range ... Same era, but racing car driver figures, nevertheless suitably dressed & equipped. They are scaled 1/43 but their dimensions fall within the typical body 'bell curve' for 1/48. Here just for you Stuart, a very rough & ready mockup, each perched on a tuffet of blue-tac .. hmmm, seems I've a little scratch in the canopy there to deal with later ... sigh!

I shall introduce you next post to two ‘signori sprezzatura’ (& that’s not Italian for malteser!)

No Ian ....... not yet 😉. I have thought one of those would be just the thing for custom masks, say for registration lettering ... Only one piece to report on, so best .. get to the point. Spinner! I'm planning an in-flight display, as is my preference, and as with similar past projects I will forgo propeller blades & just present a highly polished (spinning reeeaally fast) spinner. The Ambrosini seems to have acquired a progression of propellers in it's short active life, including some like so, with the lumps & bumps of an exposed propeller hub .. Those warty things don't work so well with the display intent, so I'm selecting this one-piece prop with spinner ... To fabricate this I laminated up no less than five lengths of evergeen styrene tubes, sleeved by their telescoping internal / external diameters. Not sure why there is a comprehensive range of tubes available, but not similar range of rod? At the centre a brass rod, and the tube projections were varied to sleeve into the nose .. Buongiorno Pinocchio!! After lopping the excess off, the brass was slipped into the drill chuck - my 'lathe' - and turned to shape. The bulk form is now done. There's a bit of fine surface filling to be done to address little pits & divots at a few of the 'tree rings' where tubes weren't fully welded together. Also need plug that little hole & bring the tip to a point ... This job shuffled up the task list as it's one which needs shaped in context with the full-length form, fuselage - canopy - nose - spinner. To this end, again, the vacform buck + styrene draw is most helpful. I've come to realise that as I next work up the cockpit detail, the opening will be closing up & I'll no longer be able to insert the buck. So I'm seeking to clear any tasks such as this first ...

Hi Dave, it’s Tamiya Epoxy Putty ‘Quick Type’. I’m finding it very user friendly, workable with a little water at hand for whenever it gets a bit sticky. Most times I’ve used it in fairly heavy applications, so I’ve conservatively left it 18 - 24hrs before sanding, so I can’t actually attest to how ‘quick’ this ‘type’ is. Look for it in the green box seen at back of this earlier image ..

Nicely done Dave, lovely silver sheen. Congratulations. Most impressed by your judgement re improvements - especially that this included removal of detail for a more ‘true’ outcome.

G'evening & thanks all for the enthusiasm for the canopy! That's the plan Ian .. which reminds me I keep forgetting to try a strip of that aluminium tape on a clear PETG offcut to see how the adhesive face looks when seen through the canopy from the other side. That may change my plans ... OK, well then, here you go ... At last post I had anchored the bulkhead (bedhead?) at the back of the cockpit & then applied epoxy behind. This doubtless could be done more efficiently, or at least more elegantly ... I'm afraid cake frosting has never been my skill! A reminder that back at an earlier stage I had been thinking ahead to this moment, affixing a styrene 'spine' to the raised ridgeline profile, coordinated with the emerging canopy ... ... the theory being to sand back the epoxy until the tope edge of this guide appeared. Well, as evidenced by the second helping of cake frosting seen below, it turned out that guide was .. misguided! Too shallow .. As seen above, the canopy buck overlaid with the spare opaque styrene draw stands in nicely for the clear canopy, allowing me to keep that at a safe distance from all things scratchy. With Ambrosini's lovely sweeping ridgeline profile now formed in 2D elevation, a centreline was drafted for me to work to & protect as the remaining 3D form is extracted from putty ... I elected to start forming the upper 'hump' first. To define a line to work down to I rigged up this flexible 'bendy rule' from brass rod, eyeballed the desired subtle curve from photos & marked on the surface ... After quite some tentative work the upper hump was pinched in, say 80% done, then tape to flip the guide line ready to finish off the lower portion that merges into the fuselage ... And after yet more tentative work I think that starboard side is now finished in bulk. Here I'm stopping for now. I'll return to bring the port side up to match when refreshed, hopefully soon.

Agreed. They were certainly squeezing the most out of the airframe to support that little V8 engine. Ambrosini carried the canopy treatment over in the first iteration of military prototype, the SAI.107 MM 441. Unlike the two-seat racer, this was now a single-seat fighter, sat way down the back there, while the canopy was of even greater length due to the extended nose housing uprated V12 motor! Your surmise seems right Ian, as the reference book states "the aerodynamic advantages of this solution were cancelled by visibility and refraction problems unacceptable for a fighter". Subsequent prototypes dropped this canopy design. In the spirit of the above trial & error, here follows my efforts with the canopy at scale. First, for the record, here's the finish I mentioned last post - possibly the smoothest, shiniest thing I've ever produced! ... but as it turned out, not the cleverest. The Mr Surfacer had a very limited durability. In all I managed 3x draws: Clear PETG direct over the buck. OK result - thankfully no 'orange peel' finish - but a few imperfections. Miniscule dust dot distortion, but so fine that they can't be felt on the outside; White styrene over the buck (as advised @Malc2 / Gordon Stephens). Super smooth external finish, left to cool on buck for next draw; Clear PETG over the styrene draw. It didn't fuse together, so that proves the method, but as I had not made allowance for the double layer, it looked a little bloated. At this point I removed the styrene ... to find the Mr Surfacer had passed it's limit ... So - be warned, follow me not! I really don't want to be stuck forever refinishing & refinishing this thing, and am mindful that the form must be compromised a little each time it is reworked. I also cannot provide a laboratorial dust-free environment, so that could continue to impact results. So I took the first clear PETG draw, trimmed the excess, gave it a wash, forgave the impurities & have declared it good enough, allowing me to move forward! Without the distraction of framing, it really is a vast - if narrow - canopy! I'm very pleased that I was redirected to delay implementing the framing. It gives a certain optical consistency, as advised. Thanks again all! Fit is satisfyingly sound, sides & forward. At the rear there's a marked discrepancy, but one which has been anticipated. With the canopy now formed I was able to use it as a template, carefully tracing with marker onto blue tape fixed to a thick styrene 'bulkhead'. This now lets me follow through with bulk-out, ready to re-profile the rear fuselage spine. Epoxy curing .. canopy put in a very safe place (really don't want to be sent back on that one!)

No need apologise Malc - this is valued input, most appreciated that you & all here take the time to assist. So, from your response: - varnish: good to have your feedback triangulate my own musing, shan’t be doing that again; - preheating: noted & will be implemented, thanks & thanks Ian too - raw timber: this might have been the wisest course, but I muddied things by epoxying the grooves left after removing the micro tubing. I’ve thought one consistent overall finish preferred, hence the coating of Mr White Surfacer (wisdom of this supposition yet to be tested!!) - styrene first draw: this is a curious option, but one I might keep up my sleeve in case the above mentioned Mr Surfacer coating proves detrimental. Encasing that in a thin shroud of styrene might be preferable to stripping back! A full week of high humidity & rain ahead here, so there will be some delay, but keen to try soonest thereafter…

Thanks Ian, yes banyan tree roots seem to be my specialty! .. yes drilling holes remains an option in reserve, however initial draw shows the PETG pulling close to shape without them. So after all the valued input here I peeled off all that canopy framing, resolving to add that after. I left the nickel tube piano hinges in place on top .. recognising that if I removed them I’d need fill & refinish .. this was just avoiding the inevitable as it turned out! Next I cleaned it up & then sprayed several coats of a high-gloss, one-part polyurethane varnish, supposedly heat resistant. A final polish after several days to harden. So, time to form .. As mentioned above, the plastic drew into the side scallops satisfactorily, so that was good. However the top piano hinge tubes resulted in overly bloated bulges .. I guess validating the advice here that framing would have done the same .. Of more concern though is an unfortunate finish on the inner surface. It has proven difficult to photograph. A subtle reversed ‘orange peel’ effect, as though the varnish coat is not as smooth as I believed, or perhaps it reacted with the hot plastic? This wasn’t a problem - or even perceptible - on the cowl, as it doesn’t carry through to the external face, but this clear piece is less forgiving. I briefly tried micromesh / polishing it out .. but that quickly proved unworkable. So I have extracted the tubing; epoxy puttied their absence; sanded back the varnish; brush coated a slather of Mr Surfacer 1500; sanded; sprayed multiple coats of yet more Mr Surfacer; rubbed down with the descending grades of micromesh; & polished with the suite of Tamiya compounds. I don’t think I’ve ever generated such a smooth finished element before - here’s hoping to goodness it yields a result! Again I’ll let it sit for a day or so before rigging up the Vacformer again .. Fingers crossed! 🤞

Congratulations! What a beauty, lovingly crafted with skill. I’m most impressed. .. really?? This makes me nervous, I keep all my clutter, jigs & bits, because I’ve proven highly prone to accidents involving gravity!! Heaven forbid, but as insurance for future repairs?

What a great exercise for the eye! Fascinating how each camouflage pattern lifts or hides elements of the design. And shows an impressive skill range there Adrian! Excellent choice of subject. Such a shapely machine - I see it as definitive evidence that the Italians really would have preferred to keep on with their interwar air-racers rather than combat machines!!

Close to 3x months before I took up your kind invitation Matt - what a nerve! It’s been a year of challenges for my family .. we’ve had our fill of all things medical. However I am finding (needing?) time back at the cutting mat, I’ve a build thread on here again - Ambrosini SAI.7 racer. Not white metal this time, resin. And again, yes, no prop blades needed sir. Great to see you moving these Chiltons along, & sharing the thread with others like-minded. It’s quite a unique treat to see the work presented against those original masters. While rearranging the household here to suit changing needs, I had the task of relocating my stash. Those little LDM boxes still surprise with their hefty weight, ‘tis it a gold ingot in there?? Treasure for sure.

Buongiorno Brits! Thank you for all the thoughtful input re canopy. These have led me to reassess, and I have taken the necessary 'one step back' but as yet without reward of 'two steps forward', so until then I'll not be updating on that. However other work is progressing! The cowling. The timber buck was finalised, several coats of varnish with sanding between & polishing after. A few test draws led to an evolved plinth'n'packer, ply'n'pine arrangement in an attempt to minimise webbing (resulting from the overly tall proportioning) and pull the plastic flush to the shape. To the latter end, I implemented @AdrianMF advice & drilled a pinhole on top as the plastic wasn't pulling in under the spinner. That drill hole necessarily goes all the way through the layer-cake, and given the length it actually telescopes up in diameter the further down it goes .. not sure if that actually made a difference! The selected draw was then progressively trimmed back to the buck, which was retained for as long as possible for workable strength as the plastic was drawn quite thin & fragile. Webbing to the undersides was limited & had actually fused into one, so not too much damage to repair. Thereafter cowl panels were laminated on & a nose panel joint scribed ... Unavoidably messy that laminating, however that's OK as they are they sanded down as much as I dare to make them as thin & subtle as possible. With that done the buck was removed & various styrene strips, rods, & tube added for internal reinforcement - a dozen extra pieces! - then nose openings drilled & shaped ... I've delayed fully opening the exhaust slots, until I've resolved how I'm going to execute the exhausts which are to fill said slots. So until then, this has largely completed the cowling ... Oh! And in parallel, in small increments - matched to my patience with the fiddly tasks - I have progressed the motor which will fill that cowling. Painting done, 16 pushrods fixed in place & the two halves now joined together. Considered against the front view above, I think this is not completely time-wasting, some of that will be visible ... surely ... Hope to follow this up with canopy progress soon!

Oh! Thanks. I was speculating .. great to see it available at that scale too.

Tremendous, this is great Malc, you’re doing a splendid presentation of this fine machine. Gotta say I rather like seeing it unfold with skill, without bearing the pressure or setbacks! Adrian I have had accounts that the CA Atkins kit is the best ‘out of the box’ representation of this machine, closest to available drawings & without the errors of the Merlin or Karaya versions. It will be interesting to hear what you discover .. So, we shall have a 1/72, 48 & 32 .. who’s going to step up for 1/144?

Very, very nice! 30x coats of paint Stuart, you might want to keep a tally so you don’t lose count.. Mark @2996 Victor you may have noticed already, Dekno have been promoting a new release at 1/48, but I think it is the #45 not #44 .. g.

Right, then I’ll leave that method to those few who are as well endowed as @Malc2 OK, thanks, so that sounds like a workable strategy, thin stock. I only have 0.5 at present, I’ll see what thinner I can source - presumably worthwhile whichever way I frame it.

And that - thank you - is another option with much appeal! Certainly as the period photos show the framing to be a fairly high shine metal finish … Your option would cut out the need to replicate metal finish & save on all the masking … 🤔

I did briefly contemplate if I ought to switch gender of this thing (?!) & cast then vac as per the professionals .. but then realised that my work to date won’t suit due to the allowance made for plastic over .. if reversed it would be too small all over. So, I’m loathe to start again - forwards it shall be! I think I will trial as you say, and & then if needs be tiny drill holes as per Ian’s advice ..

Wise words thank you Ian, yes I ought to .. How curious - do I understand you right, they supplied you with both? Regardless, your evidence is compelling .. I’m hoping for better than that!

Thanks Woody, I do hope it is equal each side when this is done - it's seems ok, but true test will be when it's transparent! I am indeed hoping Ian, but reserving the right to implement this if things don't go so well. Crikey! Talk about add to the 'performance anxiety'!! OK, so next phase - experimental, so this is sharing the leap into the unknown - canopy framing. I figured criteria being ever-so-slightly raised, pressure & heat resistant, malleable around curves, adhesive ... & cheap please. Came up with this stuff from a car parts store ... .. lay a strip onto silicone paper (basically sticker backing paper, sold without the sticker), then printed some parallel guide lines on adhesive label, nice and long to help get the steel rule aligned. Cutting technique took some trial, arriving at need for sharp blade, not too much pressure, multiple passes, & spinning the paper around frequently so the steel rule applies pressure to the bit to be used, as the exposed bit crinkled & dragged a bit. Application was manageable. It's thicker than kitchen foil, closer to the foil around a red wine bottle top, so you need bend it to the curves as much as adhere it. Happy with the outcome. Ridge line of the two opening sections had a piano hinge, so for these I used micro tube half embedded & CA glued into the timber, to result in half-round raised detail (will it work, we shall see?). A bit hard in the images to distinguish from the residual black centreline pen marking. Also note that one of these frames covers the cedar guide used for earlier bulk shaping. However I see here it seems I muffed-up some setout, as shown below, I think I have the mid-height horizontals a little low (the frames for the little sliding windows etc) ... Luckily these strips can be carefully peeled off without damage to the timber, and can even be repositioned if I don't crease or tear them in the process. I'll fix that tomorrow hopefully, then I'm thinking I'll seal them in place with an overall spray varnish to the lot (with a polish?) before committing to vacforming. Getting close now!

Thanks Dave, yes how?? That query kept my mind busy for some time. Here’s the method I arrived at.. The starting point: here below can be seen the canopy buck extracted, showing the mishmash of stuff underneath that held it together & plugged it firmly in place in the cockpit opening. Bottom left is a fresh jig of sandwiched boxboard & PVA, with a matching hole to receive the canopy buck .. .. like so, Note above the end guide profile, with the concave geometry relationship to the stacked card either side. These stacks provide a level ‘shelf’ each side to lay a razor saw blade on .. .. delivering the initial longitudinal slice as above, and after protecting the boxboard shelf with some tape, the same principle repeated but using the edge of a flat file .. .. following the sawcut, progressively opening & deepening a groove, checking as I go against the end guide profile so as not to go too deep. That groove then acted as guide to run along sanding sticks with a conveniently curved end, again keeping an eye on the end guide profile .. .. arriving at this sharp-edged concave scallop .. .. the same jig guided alignment of protective tape, getting ready to knock the top sharp edge off first .. .. and then finally address the lower sharp edge, blending it down to the cockpit sill. (note allowance made for future vac-plastic thickness) Phew! I declare the bucks ‘shaped’, only a little surface finishing remaining before ready to draw plastic!

Thanks Mark, nice feedback but I must say the most cheering bit is that your confidence that it will be ‘the finished model’!! Such an elegantly simple solution, of the kind that makes one think but of course, why did that not ever occur to me?! I will be applying this in future for sure - thanks Malc!