Auster Autocar goes to the Antipodes

[Fastcat]

It's a technique I use a lot and it works well provided the material used to fill in between has fully shrunken. I used this method or variations of it, on the headrests of the 300 SLR and the fuel tank of the Ducati. I'm not sure that epoxy is great for filling - the paint adhesion can be different. Squadron Green Stuff was my choice but any good model filler would probably do as long as it doesn't shrink a lot. For the final filling I used car spray cans to get rid of the tiny trough left by the filler but used the same technique of keeping at it until no witness of the filling could be seen.

 

 

Dave

[Derek_B]

On 29/04/2022 at 09:27, greggles.w said:

Serious effort that Derek, still airworthy?  Would be happy to see pictures here is you had them to hand ..

 

Hi Greg, yes it's still airworthy... a few pictures below. I drafted the plans and built the model (1:7.2 scale) back in the mid-80s. All the structure is to scale. My father (who is retired and so has more time for these things than I) covered it and installed electric power and RC gear about 15 years back. Time has taken a toll on the decals which are starting to peel... The interior is fairly sparse, just an instrument panel and front seats. It was my first scale RC model, so I went for practicality rather than intricate detail...

 

 

 

[ianwau]

On 4/27/2022 at 11:11 PM, greggles.w said:

My thinking is that the brass should: hold a stiffer straight edge; be sturdy to tool against when filling the voids (with? epoxy?)

I too thought you had 'skinning' in mind - but see you plan to use filler.   A possible idea would be to use car repair 'bog'/putty - available from your favourite auto supplies shop (Supercheap, Auto1, Repco etc). It's a 2 pack mix (ie 'golf ball' of part A and a 'pea' of part B and is actually 25% styrene. Rather messy to apply but beautiful to sand back to a former such as you have here. A little fettling should allow you to scallop out between formers.  Hope that makes sense??  

 

(My point of reference is I use car bog ALL the time for backfilling skeleton frames for scratchbuild moulding (eg my Piper Comanche scratch if you've followed that))

[greggles.w]

On 5/1/2022 at 9:42 PM, Derek_B said:

Hi Greg, yes it's still airworthy... a few pictures below. I drafted the plans and built the model (1:7.2 scale) back in the mid-80s. All the structure is to scale. My father (who is retired and so has more time for these things than I) covered it and installed electric power and RC gear about 15 years back. Time has taken a toll on the decals which are starting to peel... The interior is fairly sparse, just an instrument panel and front seats. It was my first scale RC model, so I went for practicality rather than intricate detail...

Wow - what a beauty!  Full credit to you for duplicating the space-frame structure - particularly as it would need to be structural!  And nice to be able to open the doors. Lovely.

 

13 hours ago, ianwau said:

A possible idea would be to use car repair 'bog'/putty - available from your favourite auto supplies shop (Supercheap, Auto1, Repco etc). It's a 2 pack mix (ie 'golf ball' of part A and a 'pea' of part B and is actually 25% styrene. Rather messy to apply but beautiful to sand back to a former such as you have here. A little fettling should allow you to scallop out between formers.  Hope that makes sense?? 

 

Thanks Ian, makes sense, yes.  'Messy to apply' doesn't appeal so much - I have kids for that - but beautiful to sand back sounds good.  Can you confirm: given it is part styrene .. is is solvent based?  Will it dissolve, or soften, or undermine the styrene scratch-built structure I've got under the brass?

 

There's time yet for a decision ...

 

Latest body of work has been on the cardboard jig.  Cut it & jack it up & extend it ... 

 

 

.. & saw the front half off the fuselage!!

 

All this to allow for me to fabricate the forward fuselage.  Due to the extensively glazed cabin, mostly exposed spaceframe within & thin side walls, the forward fuselage cannot be built using the same bog-fill bulk-form method as the back half.  Also, with further research I believe (not an authority!) the spaceframe itself was widened for the Autocar, from the the wing trailing edge back, making for broader 'shoulders' at rear bulkhead 'E' to fit those two seats in the rear, like so ...

... so the kit fuselage was made redundant.  That said, I won't be discarding that sawn-off bit, as the portion forward of the doors is back to common parts & I can use.

[Zephyr]

Lovely work, it's shaping up (literally...) very nicely.

 

Beautiful RC model too Derek, thanks for posting the pics.

 

That fuselage diagram is absolute gold too- it should be possible to develop most Auster versions from it with considerable accuracy.

I'm trying to draw a reasonably accurate 1:6 Aiglet Trainer for RC and I think I'll scrap what I've done (based on Alf Granger's Auster III/IV/V drawing) and start again with the accurately dimensioned frame.

 

[greggles.w]

20 minutes ago, Zephyr said:

I'm trying to draw a reasonably accurate 1:6 Aiglet Trainer for RC and I think I'll scrap what I've done (based on Alf Granger's Auster III/IV/V drawing) and start again with the accurately dimensioned frame.

.. whoa, hold you’re horses! If you’re looking for reference material, I’ve been gifted quite a bit more besides, & even that one above is cropped & I haven’t posted the equivalent for flying surfaces.  Send me a PM with your email address & I can forward a pile of stuff on to you ..

[ianwau]

On 5/3/2022 at 11:15 AM, greggles.w said:

Messy to apply' doesn't appeal so much - I have kids for that - but beautiful to sand back sounds good.  Can you confirm: given it is part styrene .. is is solvent based?  Will it dissolve, or soften, or undermine the styrene scratch-built structure I've got under the brass?

I'm confident it won't attack the styrene for this application. Once it's 'gone off' (about 10 minutes) there's no residual solvents etc. 

• It does generate a bit of heat during the curing process - but you don't have a large cubic volume here so can't see that being an issue. 
• When I say messy - it'll take about 3+ coats to get it up to the level you're after. You sort of overfill it when applying, then sand back to the former. Then refill the bits that remain underfilled. 
• It is a very similar 'hardness' to your styrene formers - which is why it's easy to sand back. 
• Maybe experiment on something roughed up first before committing all your fine precision work to it????  It'd be my natural 'go to' for this application but obviously you'll need to be comfortable beforehand.
• You'll get a bit of an idea of how it comes together from the earlier pix in this flickr album (a NZ cropduster scratchbuild which uses the 'bog' to create a fuse former)  https://flickr.com/photos/164110839@N02/albums/72157713840282578 

 

[greggles.w]

2 hours ago, ianwau said:

I'm confident it won't attack the styrene for this application.

This is reassuring, and the detailed response is genuinely appreciated Ian. I am convinced!  Care to share brand name/s?

 

 

I was ready to post a satisfied update, and was musing & measuring for next steps when I found I’ve made an error .. too miffed to detail now.  Suffice to say: scratchbuilt works have been assembling precisely as per jig … but insofar as that jig contains an error …

 

I think I can recover it, but best walk away for now.

 

 

[greggles.w]

2 hours ago, ianwau said:

You'll get a bit of an idea of how it comes together from the earlier pix in this flickr album (a NZ cropduster scratchbuild which uses the 'bog' to create a fuse former)  https://flickr.com/photos/164110839@N02/albums/72157713840282578 

.. & this is tremendous! What a machine!  And most instructive. Interesting to see a singular buck used for multiple vacforms, side to side & again upright for the canopy. Great stuff, not least for taking my mind off my stuff-up!

[AdrianMF]

Shame about your problem with the jig - I hope it's recoverable. I guess the Auster is a bit like the Proctor, in that they supersized the fuselage on the later versions.

 

FWIW I've used Isopon P38 (UK car filler) with polystyrene bulkheads a number of times and it doesn't harm them. There is a slight interaction on the surface, but it is structurally sound.

 

Regards,

Adrian

[Biggu]

Fantastic engineering and build, one to watch for sure, most interesting, looking forward to more !

Jeff

[ianwau]

On 5/5/2022 at 10:36 PM, greggles.w said:

Care to share brand name/s?

Re the car bog - I have no favourites as invariably using for making bucks, which are not fussy.      The one I am using at the moment is Septone brand which is much runnier (like treacle) than I'm used to (like yoghurt) - but this might well suit your purposes.  I see a separate recommendation for Isopon P38 which I think is available in AU.   

 

On 5/5/2022 at 10:58 PM, AdrianMF said:

Isopon P38 (UK car filler)

Just make sure whatever you get is 2 pack (golf ball of filler, pea of hardener) and you should see on the tin it says ~25% styrene. Below are some additional detail on the basis you'll have a crack once you rejig your mojo. 

• first coat will look pretty rough (despite your best efforts). Don't be concerned. Aim is mostly fill in the bulk of the hollows for this first coat. It's OK to overfill. You'll sand it back.
• sand back with course wet & dry (eg 180) sanded WET. Use a small sanding block (I use a chunk of balsa wood 3cm x 1cm).  Stop immediately a shadown/glimpse of your former(s) is revealed. 
• Switch  to 400 wet & dry. Sand back to smooth off the curves and (just) evenly expose the former.
• Another coat of putty. This'll start bringing it together. Sand back with 400 from the outset. Wet. 
• Another coat of putty - probably spot filling by now and filling out patches. Sand back with 800 if you're patient
• You can them apply some more conventional modelling putties, Mr.Surfacer 500, 1000 or whatever.
• Judicious sanding between the formers should give you a scalloped effect (I achieve this unintentionally with my bucks sometimes). Experiment on something else first?
• My experience is the car bog is a tad softer than styrene - which is why the scalloped effect should work. There is minimal (if any) shrinkage with the car bog)

[greggles.w]

Many thanks Adrian & again Ian re filler advice, I'm logging this away for use in the near future.

 

On 5/5/2022 at 10:58 PM, AdrianMF said:

Shame about your problem with the jig - I hope it's recoverable.

 

Yes, happily so.  Now there is some distance I can recount the detail of the error: basically a mix-up with the bulkheads - the 'D' bulkhead jig was using a few 'B' bulkhead dimensions ... sigh!  After calm analysis, rectification was principally trimming the unwanted 'peak' out of the rear cockpit sidewalls.  Here in foreground showing that which is above the yellow-tape guide-line is to be removed, ... as has been done to the other side in the background ...

 

 

... then there were a few follow-up tasks, like trimming back the front seat support / rear toe-board which was now projecting above the diagonal ...

 

To keep a feeling of going forward while forced to go backward, I also made moves on the forward cockpit.  To the left, the kit part that which was sawn off recently.  The front engine-mount bulkhead scales out just fine, and having the curved geometry ready-made is welcome, but thereafter it all needs to flare out wider to meet the new works.  So the floor was chopped out, and spine split ...

 

 

... and a new floor wedge inserted.  (you can see in background jig bulkhead 'D' chopped down to correct that error)

 

 

The jig was then added-to with a vertical 'A' bulkhead to allow for hold-in-place while I worked out how much of the residual grey 'ears' needed to be shaved back ..

 

 

Next fit the uniquely triangular Auster cockpit doors.  These of intentionally thinner sheet, mimicking the very thin real doors & internal sill ledge ...

 

 

... and lastly the little triangular bits behind the doors, completing the cabin 'tub' ...

 

 

The inner surfaces above are effectively 'it' - save some finishing - whereas the external faces are a bit messier, with more form making to come.

 

 

Next will be more styrene-supported brass stringers down the sides, extending from tailplane leading edge to cockpit doors ...

 

Very pleased to be back on track!

 

[ianwau]

Glad the mojo was resdiscovered. Be thankful you discovered the glitch as early as you did - a relatively quick fix it seems.

 

It's certainly looking the goods! The donor kit looks very much a "grandpa's axe" for the fuselage  (ie by the time you've replaced the "blade" and the "handle", there's not much left!).   You may recall my 1/48 J4 Archer scratchbuild from last year - I ended up just scratching the whole fuse, but it lacks some of the finesse you'll achieve with your approach to the stringers. 

[greggles.w]

6 hours ago, ianwau said:

The donor kit looks very much a "grandpa's axe" for the fuselage  (ie by the time you've replaced the "blade" and the "handle", there's not much left!).   You may recall my 1/48 J4 Archer scratchbuild from last year - I ended up just scratching the whole fuse,

Ian, I can’t think why I didn’t join the dots earlier! I had come across your scratchbuild Archer when poking around for kit options. I seem to recall thinking ‘scratchbuilding? Ha! Let’s keep looking, surely there’s a kit to be had’ …

 

Now I return to your thread & note with a chuckle your prophetic words in your first post:

 

“there's slim pickings in 1/48 - the Sword kit of the Auster Mk.III is more suited to military use … So much so that you'd end up scratchbuilding most of the fuselage anyway.”

 

How true, yes I am! Seems I don’t have your foresight.

 

I’m going to read back through yours in a more considered way now, as you have proven yourself the oracle!!

 

Your outcome looks great, congratulations!

 

A link here for any other readers looking for a meaty WIP Auster thread:

 

.. and the finished item:

 

 

[Zephyr]

Good save! The J/5 fuselage isn't the easiest shape to capture- it looks pretty simple at first glance but there are a lot of subtle contours.

 

 

[greggles.w]

7 minutes ago, Zephyr said:

Good save! The J/5 fuselage isn't the easiest shape to capture- it looks pretty simple at first glance but there are a lot of subtle contours.

 

 

Thanks & you’re not wrong Richard!  All those triangular faces with vertexes projecting or recessing or aligning.. and those backwards-leaning verticals!

 

You've caught me now pondering the next bit forwards: the cowl etc.  I know the engine bulkhead was changed from vertical as per the kit MkIII, to be on a backwards reclining angle for the J5P (parallel to door hinged edge). And I can see the rear cowl changed from a venting gap all the way round the sides & bottom for the MkIII to bottom edge only for the J5P.  But it also seems to me that the Mk III ridge line of the cowl has a more pronounced ‘droop’ from windscreen to prop than the J5P … but as yet I can’t quite confirm as there are so few fixed lines or 90deg angles to benchmark from, & the various military anti-glare or civil pinstripe paint jobs act like dazzle camouflage!!

 

I have good J5 drawings with clear profile view, but not for the MkIII to compare …

 

More investigation needed!

[Zephyr]

At this point, having just looked at enough photos to start losing perspective on the whole thing, I think that the top of the cowl is horizontal/parallel to the fuselage datum on the J/5B, J/5P and Aiglet Trainer only.

In other words, every version with the J/5 fuselage and a Gipsy engine.

The J/5s with the Blackburn Cirrus engine seem to have the top of the cowl sloping downward, similar to the J/1.

 

 

 

[greggles.w]

17 hours ago, Zephyr said:

At this point, having just looked at enough photos to start losing perspective on the whole thing, I think that the top of the cowl is horizontal/parallel to the fuselage datum on the J/5B, J/5P and Aiglet Trainer only.

In other words, every version with the J/5 fuselage and a Gipsy engine.

The J/5s with the Blackburn Cirrus engine seem to have the top of the cowl sloping downward, similar to the J/1.

 

 

 

D'you know, I think you've cracked the code - well done & thank you!  I have gone back through my little library of accumulated J5-version photos & looking with your comment in mind it seems so!  Thanks for taking the time to put your deductive mind to that (& thanks for the Mk III plans, most appreciated!)

Edited May 11, 2022 by greggles.w

[greggles.w]

.. inching along this week. A little effort to prepare for stringers down the flanks.

 

First gouging out trenches into which the end of the brass rod can disappear..

 

Then some linking projecting webs.  All getting quite small & fiddly, so these went on overly tall & then were sanded down, with much squinting to sight down the sides with a scrap length of brass in place…
 

 

[Malc2]

Looking good, I have seen this brass wire and filler technique used very successfully by Marcin Matejkoy on his scratch built 1/32 Laird Turner Meteor.

 

Malc.

[ianwau]

I'm responding to your canopy vacform query in this thread (didn't want to hijack @Farmer matt in his LDM build!).  For vacforming clear canopies - I don't do any additional prep/coatings on the buck other than using fine sandpaper (eg 1500, 3000). I did try sealing/priming once - and it delaminated onto the part due to heat!

 

In terms of oven technique - there's plenty of experience here on BM. Here's my 2 cents worth (90% success rate):

• Have the vacuum all set up, with the buck in position on your sucking frame. 
• Use the overhead grill setting in your oven - about 200 celsius in mine (ie moderately hot, say 8 out of 10??).
• Plastic sandwich about 50mm under element.
• Plastic sandwich chocked up about 50mm from tray underneath (to allow for slump). 
• My oven usually takes about 3 mins  - the indicator is material slump in the plastic (~10-20mm depending on size of your sheet).
• Vac on. Then in one smooth movement using two hands, two feet, and your teeth - whack it on the sucking frame.
• You'll know in about 1/10 of a second if you have a hit vs miss.
• [** for clear I am using 0.75mm ie 30thou PETG or Butyrate - good for 1/48]

Another Flickr album shows a more expansive canopy mould (1/48 Piaggio P.166 scratch) using this technique

https://www.flickr.com/photos/164110839@N02/albums/72157677096038867

 

Just sharing what works for me - hopefully useful!!  Incidentally - love your speaker-box conversion to vacform machine.  Looks like a work of art, with precision drilled and evenly spaced holes vs my backyard effort!

 

Edited May 14, 2022 by ianwau
typo

[greggles.w]

Many thanks Ian for the targeted vacform advice, very much appreciated! Not to be immediately drawn upon, but bookmarked for the hopefully not-too-distant future!

 

The next step in that direction: engine bulkhead.  Yet another variation to the kit required!  The J5 series - including the subject J5P - introduced a sloping engine bulkhead, in contrast to the earlier vertical arrangement.  This pair of Austers make the contrast, foreground being the vertical as per the kit, background being the reclining to be replicated..

 

 

After examination of references it seems  it’s not that the whole plane was reclined, so much as the ‘chin’ juts forwards.  This arising from the geometry of the spaceframe within, presumably to give increased foot-room while avoiding any reconfiguring of the upper windshield & instrument area.  This Autocar image shows it clearest.  The top 1/4 is vertical, down to the cowl panel joint, then the lower part slopes away forwards ..

 

 

.. well that’s my best surmise!

 

So a wedged piece of thick styrene sandwiched between thin & slapped on the front face like so ..

 

 

.. the vertical jig ‘A’ was pulled off & repurposed as a shelf of sorts .. the flexibility of cardboard jigs ..

 

After that thin sheets laminated to both ‘cheeks’ & sanded back to resolve the form ..

 

And with that diversion done, I dutifully returned to finish off the long brass stringers down the flanks ..

 

 

24x of them, top & sides .. one of those tasks I’ve learnt are best counted after rather than before!  Only 3x remain along the belly .. actually .. then it’ll be ready to ‘bog-up’!

[greggles.w]

Not a model update tonight, just an extract from a newly uncovered account of this machine’s epic flight. Uncovered in February 2021 Air Pilot, an account of the 1969 BP Air Race by the pilot of another Auster - 1944 J1N G-ARGT - which was an offical entrant (“the slowest aircraft in the race”).  Along the way they kept company with Richard as he shadowed the participants.  Amongst the various anecdotes was this amazing one about our machine & pilot Richard Rudd:

 

“… Some considerable time after his fuel would have run out our man appeared looking a little disheveled. He had landed in the desert [the Rann of Kutch, straddling the disputed Pakistan - India border] after the cable controlling his left aileron had come off a pulley just above his head.The immediate effect was to cause the aircraft to roll to one side which must have given him quite a fright. Somehow he managed to land the aircraft operating the loose cable with one hand and moving the other aileron with the joystick. At any rate he was safe and sound and we would meet again en route.”

 

!!!

[greggles.w]

Another image-less post ..

 

I raised a query 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.