Auster Autocar goes to the Antipodes

[heloman1]

Excellent work going on here, I do like the way you have tackled the ribbing.

 

Colin

[ianwau]

On 5/25/2022 at 10:21 AM, greggles.w said:

uery re undercarriage length on an Auster enthusiast F’Book page, and amongst the responses was a Richard Rudd - since confirmed to be THE Richard Rudd, pilot of this machine on this epic flight! What a happy coincidence!!

 

Now in conversation, already yielding a surprise - the tail colour was apparently a dark Matt green, not grey as I thought.

Wonderful discovery - both in making contact with Richard, and discovering some new facts re colour.  Normally that doesn't come to light until AFTER you've finished the model! Great progress on that fuse - really interested to see how it comes together with the filler and judicious sanding.

[Zephyr]

You can't beat that as a reference source!

Still, cynical me is waiting for someone to look at the finished model and tell you the colour is wrong...

[greggles.w]

On 5/27/2022 at 6:16 PM, heloman1 said:

Excellent work going on here, I do like the way you have tackled the ribbing.

 

Colin

Welcome & thanks Colin! Pleased you approve of the ribbing .. although we're only halfway through the process, let's see how they perform when the filler goes on.

 

That said, I am pleased to report they are now complete, with the underside finished.

 

The MkIII Auster (top in image below) had a discernibly 'concave' under-side profile - correctly replicated in the Sword kit - while the Autocar (bottom in image below) had the reverse, with a notably 'convex' belly..

 

 

As can be seen with the dashed innards on the drawing, I don't believe this actually delivered any additional useful internal space.  It seems the form was bulked-out for a general impression of roominess when viewed externally.  The floor still sits at the bottom steel frame longeron, with a timber frame & stringers below as shown here in this helpful diagram from the manual ...

 

 

... which allowed me to dutifully replicate in brass packed up on styrene bits'n'pieces ...

 

 

And here's the comparison: belly concave / belly convex ..

 

 

(... and engine bulkhead vertical / sloping again)

 

So I'm going to let all that chemical fully cure.  I've bought my tin of car 'bog' as suggested, ready for the next step!

 

[greggles.w]

I see in my last post I was promising filler next .. but I’ve found something to procrastinate on instead. The cowling.

 

Once again the kit MkIII part is quite different from the later Autocar. In part this is associated with that bulkhead change, but also engine mount changes to maintain centre of gravity concurrent with all the other variant airframe changes, and not least a change from cowl sides lapped & venting to cowl sides flush with fuselage and venting out bottom only.

 

So I’m preparing a block of basswood to shape into a buck for vacforming a new cowl. This part will extend from bulkhead out to meet the kit cowl face (which happily looks the part) …

 

.. it’s not so clear to see in that image, but there’s been quite a bit of geometric gymnastics to get this far.  That block in profile is actually a backwards reclining parallelogram. I found it useful to draft various lines and angles on blue painters masking tape laid out on cutting mat, which were then transferred across to guide trimming the block faces.

 

From here it gets a bit more free form trimming, whittling & sanding ..

[greggles.w]

.. whittling, so satisfying! Lovely wood to work with this basswood ..

 

And then filing & coarse sand …

 

 

 

Now I ‘just’ need shave off an allowance all-round for the vac-form plastic thickness.  For some reason this has me quite nervous .. how much, & how to judge an even reduction?  Need ‘just’ give it a go I guess …

[Zephyr]

Female mould...?

I've never done it but it might be worth consideration.

 

 

[greggles.w]

1 minute ago, Zephyr said:

Female mould...?

I've never done it but it might be worth consideration.

 

 

Oh! Didn’t think of that .. d’you mean make some sort of casting of this bit of wood, then vac down into that cavity?

[Zephyr]

Yep, although having said it I'm not 100% sure how you'd do it.

A plaster mould maybe, and make each part a bit more than half the width so you can sand the plastic parts to fit.

I DO know that you should generally drill some vacuum holes in a female mould.

[ianwau]

On 5/29/2022 at 10:16 PM, greggles.w said:

I've bought my tin of car 'bog' as suggested, ready for the next step!

I assume you'll trial the bog out on some sacrificial brass and styrene conglomeration.  To check it gives the effect you want and sands out in an ever so slightly dished manner? Just for my sake!

 

This is definitely a multimedia kit - looks like most of the modelling materials and techniques all rolled into one.  Definitely enjoyable to follow. 

[greggles.w]

On 6/7/2022 at 1:49 PM, ianwau said:

I assume you'll trial the bog out on some sacrificial brass and styrene conglomeration.  To check it gives the effect you want and sands out in an ever so slightly dished manner? Just for my sake!

Yes, rest assured, will do & in any case Ian, know I will not hold you to blame for any error on my part!

[greggles.w]

I’ve been diverted, but back at it …

 

I’ve carefully sanded back all faces of the cowl wood buck, all quite unscientific.. trial & error with option to vary plastic sheet thickness?

 

I’ve also had a go at this distinctive J5P Gipsy Major 10 cowl detail, starboard side, lower panel, an oil cooler scoop I believe..

 

I found nice fine diameter timber dowel sold for a pittance at a sewing & crafts store, from which I shaped the projecting portion, then I carved out the concave inverse …

 

(the oblique lighting shows the general recessing of timber relative to adjacent plastic.  The yellow tape marks the removable cowl side panel-lines for reference)

 

I’m planning to stand the buck up like so for vacform draw..

 

When the glue is cured tomorrow I’m thinking I’ll drill a hole vertically down into that circular oil-cooler face, right through to the base to try to draw the vacform plastic into the scalloped recess.  Though it looks otherwise in that image above, the projecting bit is not actually ‘undercut’, instead it’s true vertical, while the cowl tapers in from it. As shown here from plan view …

 

So I think it should vac OK (?!). We shall see …
 

[Malc2]

Looking good so far!

As a suggestion, you should add about 3mm to the front, this means you will be able to sand away the waste that forms the curved edge of the front surface and still end up with a part that is long enough.

To prevent webs (like a Banyan tree) forming round the bottom, you may need to add a block of about 5mm for it to stand on that is smaller than the profile of the cowl back edge. This means the rear edge will draw inwards preventing said webs.

If all this is not clear, please ask questions, it may be better if I make a drawing to show what I mean!

 

TBH, as its such a deep draw, using your former with 3mm added to each end (to allow for removing the waste as mentioned) I would be tempted to plunge mould each panel separately like the real aircraft (Top, bottom and two sides).

 

Which ever approach you take it will be interesting to find what works for you!

 

Malc.

[ianwau]

10 hours ago, greggles.w said:

I’m planning to stand the buck up like so for vacform draw..

 I think as @@Malc2 elegantly puts it, you have a risk of Banyan Tree roots if trying for a single shot - but by all means give it a go. My leaning would be to mould in two parts - port and starboard? No need to cut the master - as having it sit a little higher will be good to avoid the Banyans.

 

As an example below, this canopy vacform still had some Banyan tree roots in unimportant area. The master you can see on the vacforming machine(!!!) is bluetacked at the moulding position. 

 

 

 

[greggles.w]

23 minutes ago, ianwau said:

 I think as @@Malc2 elegantly puts it, you have a risk of Banyan Tree roots if trying for a single shot - but by all means give it a go. My leaning would be to mould in two parts - port and starboard? No need to cut the master - as having it sit a little higher will be good to avoid the Banyans.

 

Sincere thanks both @Malc2 & @ianwau for engaging in such detail and with such specifically targeted advice.

 

I'm not unfamiliar with ‘the banyans’, with my last (first!) effort at vacforming engine cowling components resulting in this likeness to Angkor Wat!!

 

 

.. all that to create these ..

 

 

.. from this buck ..

 

.. which after much trial and error was supported on this for the definitive draws ..

 

Now I do not post the above to assert expertise! That was grossly inefficient & a new approach was clearly needed.

 

Gents, I do like your examples & advice that ‘parts’ can be drawn from a whole buck.  I had the mental block that a half-output required a half-buck, this gives me more options to consider … thanks again!

[ianwau]

Love that vacformed engine cowling - a work of art!

 

Maybe useful to share another example.  This is a 1/48 Victa R2 (L=130mm approx) - with 3 moulds vacformed off same buck. Top and bottom halves moulded in 0.75mm white, and a top half in 0.75mm clear (from which the clear canopy is cut).

• Each "half" has moulded well over half of the buck (more like 3/4). 
• The fuse half that's still in situ has Banyans at front and rear - but strong suction and hottish styrene meant the plastic pretty much rejoined under the tail!
• Note I have relatively small vertical separation between buck and vac box - ~5mm?

 

 

 

[greggles.w]

If one had foresight, one would very carefully & soberly consider before embarking on building an Auster kit, let alone converting an Auster kit, for the principle reason that it's the canopy that holds everything together, at that primary crucifix junction of wing & fuselage (plus a little dihedral & angle of incidence for good measure!).  Luckily I have a notable absence of foresight, so here we go with this next challenge!

 

The kit delivers this critical part as a vacform transparency - helpfully provided in duplicate as they had foresight! - to which one is asked to butt-joint fix the wings ...

 

 

There are many differences from this early Mk III to J5P Autocar: generally the glazed extent reduced in length but bulked in width to accommodate the 2x additional seats; the surfaces changed from planar to curved; the Perspex sheet sizes increased & framing therefore reduced.  Not least illustrated by the windscreen, which developed from flat multi-paned & facetted to a singular rounded 'plastic' form that includes merged wing-root transitions, as shown here another J5P VH-KCB ..

 

 

So I have been busy preparing a buck as basis for a alternate vacform canopy.

 

Step 1, taking a 1" square 'stick' of basswood & breaking it into 3x 'blocks' ...

 

 

Next, put those blocks back together again, glued 'n screwed, but sandwiching cedar veneer bulkhead profiles in-between ...

 

 

With it back in one piece, next was excavation, whittling with a blade, then coarse sanding to a point of bulk form and correct profile along the spine - all working toward the cedar guides within ...

 

 

The shaping was taken only so far .. hovering about a millimetre or so above the cedar to give margin for next stages.

 

[At this stage, I dropped the fuselage on the floor.  One stabiliser popped off, one brass stringer 'sprung'.  I was not inclined to photomontage that regression & recovery!]

 

Now I'm into final detail shaping - cutting in the aerofoil profile for shoulder wing junctions, and then tapering the sides to meet the underside smoothly, creeping slowly closer to the cedar guides  ...

 

 

Now, with this post, I am procrastinating on that last area of detail shaping ... the wrapping, reclining & merging-to-wing windscreen ... wish me luck!!

 

[Malc2]

Great post, thanks for showing the progress.

 

Malc.

[AdrianMF]

3 hours ago, greggles.w said:

the wrapping, reclining & merging-to-wing windscreen

I have a feeling that the cockpit guy at the Auster company did not like modellers.

 

Looking good so far.

 

Regards,

Adrian

 

 

[ianwau]

Quite a woodworking masterclass! Thank you for sharing.  I can only imagine the wood shavings/dust you must have created to get this fine end result.  What sort of tools do you use for the whittling - power vs hand?

[greggles.w]

On 7/11/2022 at 5:58 PM, Malc2 said:

Great post, thanks for showing the progress.

 

Malc.

Thanks Malc!

 

On 7/12/2022 at 9:10 PM, ianwau said:

What sort of tools do you use for the whittling - power vs hand?

Hand tools Ian. For the whittling specifically, my olfa cutter .. careful asking about that tool, I can be a little too effusive in my praise for that one! I’ll make a post for your amusement soon showing the assemblage of tools-to-hand which were brought to bear.

 

On 7/11/2022 at 6:12 PM, AdrianMF said:

I have a feeling that the cockpit guy at the Auster company did not like modellers.

Quite so Adrien! And if I pass this trial-by-canopy then his next ordeal is the tubular spaceframe revealed within!!

Here’s today’s progress on the windscreen…

 

 

 

 

I think that closes out the form, from here it’s down to the finish.

 

A question for you @ianwau please, or others with experience of this stuff: can you recommend a filler, or putty that I can smear over those exposed cedar edges? It’s not about appearance. They are generally blending in well, it’s just the veneer was oriented such that the end grain is at the top, and I get the feeling I could sand it down to the ground & it would still have a sort of ‘pitted’ open grain texture.  Am I being overly worried to think I need ‘something special’ to resist the heat & pressure of vacforming?  Any sage advice much appreciated!

 

G’night all …

 

[AdrianMF]

The windscreen looks great! For a small amount of infill like that, If the cedar is below the surface (looks to be) then I'd go for Milliput, but if it's level with the surface I'd simply cover the edge it with medium CA glue to soak into the grain and seal it. I've used both and they survive vacform temperatures for as many goes as I've needed to get a good 'un.

 

Regards,

Adrian

[k5054nz]

I always enjoy seeing updates on this! Austers are sadly underserved in kit form - I'd personally love 1/72 and 1/48 examples of the Autocrat.

[Paul J]

 Fascinating amount of work going on here. There can't be much of the Sword kit being used. Except maybe the wings. Looking forward to seeing the end result.

[ianwau]

21 hours ago, greggles.w said:

ecommend a filler, or putty that I can smear over those exposed cedar edges?

Hmm - I'd go with @AdrianMF views on Milliput which I've found resilient - haven't tried CA for this myself.  Have also seen some enlightened responses on  your post in the FB Vacform/Resin Group, and zeroed in on the Devcon High Heat two part epoxy advice?  Definitely need something for sure.  Keen to see what you come up with - this is all expanding my techniques!