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New 1/48th Airfix Hurricane vs Bentley...


Troy Smith

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I recall being informed a few times previously that photocopying can 'adjust' the size of the original slightly and if copies are made of copies, then the error is compounded. Could that be the root of the phenomenon seen here?

I'm not sure if nowadays this is much of a problem- what remains as a problem is Humidity! (And I'm not getting hot under the collar here...).

I've personally witnessed how pieces of paper move quite a bit with changing humidity, this is especially apparent if you try to join two sheets of paper: Today they may butt perfectly, but tomorrow with a change in humidity they just won't line up over all of the joint.

AutoDesk/AutoCAD have a piece of software (rubber sheeting program) to specifically deal with the paper image instability problem- you scan the drawing, import it into the program and then establish 'control points' using known dimensions- the program will then stretch and pull the digital image until it establishes the best fit to your control points. Then you use another program (called raster to vector ( bitmap to scalable ) ) to trace the image either manually, automatically or semi-manually.

Published Dimensions are unaffected by humidity, but now how accurately do you need to transfer the dimension....

Edited by StevSmar
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As previously stated, the only valid bit in any technical drawing is the text, symbol and numbers on the dimension line.

Do they still teach it at the beginning of technical drawing class - the teacher draws a potato-shaped closed curve, dimensions it with text "Ø215 mm" and says - this is a perfect circle with a diameter of 215mm?

Vedran

The milimeter brigade

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  • 1 month later...
  • 3 weeks later...

My apologies to everyone. Its been a bad time here.

No big deal Chuck, we're all human.

If I had a $1 for every time I said something I regret, I could buy MULTIPLE COPIES OF THE AIRFIX HURRICANE KIT IF MY LOCAL HOBBY SHOP EVER GETS THE ONE I ORDERED FROM THEM IN (Or it could be two- been so long now I can't remember)...

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I'm not sure if nowadays this is much of a problem- what remains as a problem is Humidity! (And I'm not getting hot under the collar here...).

I've personally witnessed how pieces of paper move quite a bit with changing humidity, this is especially apparent if you try to join two sheets of paper: Today they may butt perfectly, but tomorrow with a change in humidity they just won't line up over all of the joint.

AutoDesk/AutoCAD have a piece of software (rubber sheeting program) to specifically deal with the paper image instability problem- you scan the drawing, import it into the program and then establish 'control points' using known dimensions- the program will then stretch and pull the digital image until it establishes the best fit to your control points. Then you use another program (called raster to vector ( bitmap to scalable ) ) to trace the image either manually, automatically or semi-manually.

Published Dimensions are unaffected by humidity, but now how accurately do you need to transfer the dimension....

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  • 7 months later...

Can you explain more of this import fuction?...I have digital scan of of old blueprint drawing that I want to have imported in to modern CAD format

It's called rubbersheeting when you need to distort an image so that the known dimensions match the CAD dimensions:

https://en.wikipedia.org/wiki/Rubbersheeting

Raster to Vector was another program, however in my opinion it was so problamatic that it was easier to trace the image. Now that was 10 years ago so perhaps things are a lot better now. You'd think so since the image to CAD conversion problem still exists.

Edited by StevSmar
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Six months ago the hobby shop that was going to order me the new Airfix 1/48 Hurricane said "Oh, I didn't think you were serious about wanting me to order this for you.....".

Grrrr. Anyway, I ordered one from Mr Amazon and it arrived a couple of weeks later.

WOW, I'm absolutely blown away at what Airfix has done with this kit. I'm very picky (but not a rivet counter) and I've yet to find something that disturbs me.

A big thumbs up from me!!!!!!

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Six months ago the hobby shop that was going to order me the new Airfix 1/48 Hurricane said "Oh, I didn't think you were serious about wanting me to order this for you.....".

Grrrr. Anyway, I ordered one from Mr Amazon and it arrived a couple of weeks later.

WOW, I'm absolutely blown away at what Airfix has done with this kit. I'm very picky (but not a rivet counter) and I've yet to find something that disturbs me.

A big thumbs up from me!!!!!!

I'm pickier than you then Steve....

http://www.britmodeller.com/forums/index.php?/topic/234972972-airfix-148-hurricane-mk1/page-3#entry2349030

there's plenty more that lets this kit down than that.

the big one is the wing /fuselage transition, the real thing curves, the Airfix flat, fixing it requires redoing the panel fasteners, which are shown as raised discs..

see here for a fix,

http://www.britmodeller.com/forums/index.php?/topic/234986216-148-airfix-new-tool-hurricane-mki-p3039-from-no229-squadron-completed-on-31-10-at-1150-pm/page-2#entry2094476

also, the ailerons and trailing edge is way too thick, the tyres appear too big, the spinner backplates are too thick, and the DH spinner appears too long.

It's possible the fuselage is too long, this was debated here, with no conclusion, though given the other problems, I wouldn't be surprised.

I'd really hoped Airfix would 'nail it' with this kit, they didn't :(

It's not terrible, and has some advantages over the Hasegawa kit, but the above flaws were very disappointing for me,

Maybe Trumpeter will eventually shrink down their 1/24th kit, as that is really good in overall shape!

the aileron problem is compounded by having them separate, and solid, basilisk fixed this by sawing them in half(see link) but their 1/72nd Defiant has a similar problem.

Difficult to fix unless you are very skilled.

The difficulty in fixing the problems are a real shame as they got nearly everything else right.

cheers

T

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For anyone interested in the pitfalls of measuring restored aircraft and using those dimensions to make models, I would highly recommend:

Supermarine Spitfire, Restoration Manual (Haynes Restoration Manuals) Hardcover 6 Feb 2014

https://www.amazon.co.uk/Haynes-Supermarine-Restoration-restoring-Microfibre/dp/B00BHXJF7S/ref=sr_1_2?ie=UTF8&qid=1463324643&sr=8-2&keywords=Restoring+supermarine+spitfire

Around page 100 there is a wonderful description by Supermarine (manufacturers of new spitfire parts and restorers of spitfire bits) on how new build parts often have to be bastardized to fit with original parts.

Basically it may look right but it won't fit.

Unless you have a trusted DIMENSIONED drawing, your new part will likely be a characture of the original.

Lots of lovely pictures, and great text on the art of restoration as opposed to the technicalities of restoration.

I'll try to send photos of the pages I'm referring to.

Edited by StevSmar
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But those manufacturing vagaries you're speaking of disappear when scaled to 1/48.

Yes, but if you don't have a set of wings, for example, and you use wreckage for making a new set of wings, I suspect there will be a fair amount of poetic license in the reconstruction.

Let's take "KZ321", currently at vintage wings of Canada as an example. Let's say they decided to use MkIV wing replicas rather than the MkIIC wings they did use (It has replica cannon stubs IIRC). Then someone would have had to either find MkIV wing drawings or take a whole pile of measurements and almost certainly they will make some mistakes.

I've made a few projects (model airplane and other stuff), and my most common error is being off by one inch or making a mathematical error.

If a similar error was made with a pair of wings, then that could be large enough to show up on a plastic model made from measurements of those wings.

The other option we have to consider is the general arrangement drawings Mr Bentley used. He was clear in expressing his difficulty in reconsiling the difference between the GA (general arrangement) drawings and the GA's for various major sub-assemblies. I'd bet that if he had access to component drawings (individual parts) that he would have had difficulty with the differences between the component drawings and the sub-assemblies GA's.

I corresponded with Mr Bently in the early 90's and he kindly sent me copies of the drawings hawkers printed for him. Maybe 50 drawings? Certainly not a lot. He would have had to use a lot of judgement to make his drawings fit with hawkers drawings and published dimensions for the various Mk's of Hurricanes IMO.

I've heard of restorers measuring several new old stock spinners for spitfires and their length being noticeably different. Like it or not, UK aircraft were hand made and parts were often not interchangeable like the USA made parts were. An example is the Hurricanes cowlings, I've read that they were not generally interchangeable between aircraft without swearing.

It's all rather interesting... Like a good mystery. IMO the Airfix Hurricane should be considered as the best MkI 1/48 model out there. It won't be perfect, but for my tired eyes it certainly looks like a Hurricane.

Now all I have to do is fob off on some poor sod all the other non-built 1/48 scale Hurricanes that have really glaring errors on them (thanks for pointing out those errors Troy...-ROFLMAO (rolling on floor laughing my bottom off) ;):)

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Yes manufacturing vagaries etc. do apply, but as we have seen in this and other threads there is the continuing and completely erroneous habit of overlaying a kit part on a drawing, finding a mismatch and then complaining that the kit part is wrong. And thus by doing so ignoring the absolute rule that one does does not scale off drawings. Use the quoted measurements never the image which is usually distorted by printing or other forms of reproduction. Arthur Bentley did not produce manufacturing templates he produced drawings which are to any manufacturer completely different things. The Airfix Hurricane may have some minor problems but all the complaints I have seen seem mainly directed at its close fit tolerances. That should never be a problem to any halfway competent modeller.

Edited by MilneBay
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IMO the Airfix Hurricane should be considered as the best MkI 1/48 model out there. It won't be perfect, but for my tired eyes it certainly looks like a Hurricane.

It is, but it could have been so much better. If Fly could do proper research on their 1/32 model, avoiding all the mistakes Airfix did, why couldn't Airfix do so too?

Yes the new Airfix model does look like a Hurricane, but so do the Italery, Hasegawa and older Airfix incarnations of the Hurricanes with all their various faults.

My only wish is that Fly is down scaling their 1/32 Hurricane to 1/48 to give as a much better starting point.

Cheers, Peter

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When I refer to a drawing, I mean a drawing that has dimensions on it. Paper will stretch and shrink, only dimensions stay constant.

(Yes I know dimensions are not entirely accurate, because you need to translate them into a real world size. Why else is the meter now defined by Something crazy like (from Wikipedia) In 1960, the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. In 1983, the current definition was adopted.)

Basically, paper should be thought of as rubber which is humidity sensitive.... I've taken two partial drawings, copied from parts of the same master drawing, had them line up one day, and the next day, with a change in humidity, they don't line up.

To me if it looks like a Hurricane, that's good enough. Perhaps when our friends at British Aerospace see fit to release all their Hurricane drawings, some crazy will translate them into 3D CAD files and we will have our true answer on what the dimensions should have been. Of course real airplanes won't match our perfect CAD model, cause they're real airplanes with real differences.

Anyone know if Arthur Bentley produced an updated version of his Hurricane drawings on Mylar (Mylar is relatively non-humidity dependant) or better still 2D CAD direct to PDF with vector graphics. I'd love to talk to him if anyone has his number..... I really appreciate how he sent me copies of the drawings he had and started me on this journey of collecting Hurricane info. Most fun!

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  • 3 weeks later...

Troy, did you make any progress with Arthur Bentley on a further revision of his drawings?

I received the following email from Arthur Bentley regarding the revised Hurricane drawings:

The update is mainly to change the hand drawn stenciling to computer generated text in Photoshop. I have enhanced a few of the very thin lines that were breaking up due to them not being completely scanned, but other than that there are no significant changes.

So is it worthwhile to update the drawings that I have already in 1/24 scale purchased from "Scale Aviation Modeller"(?) 20+ years ago? I have asked him if they were redrawn in vector graphics, but I would say no.

I do know that Mr. Bentley generally drew on cardboard, which you would think would be a lot less susceptible to expanding/contracting than paper. So a scan done from the cardboard masters should be more accurate if purchased from Mr. Bentley. Of course now you have to make sure you print them at the right scale....

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Having spent some time working in professional cardboard design & manufacturing, I am sad to tell you that there is no difference of principle between paper and cardboard with regard to stability in relation to humidity. To the industry, cardboard *is* paper, it's just thick paper, in some cases, or in other cases multiple pieces of thin paper glued together in clever ways. As the stock gets thicker there may be a difference in the rate of change moving from a dry to a humid atmosphere, but not in the amount of change.

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a really proper response will take me a an hour or two work, but a few points,

The new 1/48th Airfix Hurricane is basically a scaled up version of their 1/72nd fabric wing kit.

I saw a built up 1/72nd fabric wing recently posted, and the same errors hit me, balloon tyres, too long DH spinner, so I dug my 72nd fabric wing kit out, and noticed this has the same side panel error that is the deal breaker for me,

http://www.britmodeller.com/forums/index.php?/topic/234986216-148-airfix-new-tool-hurricane-mki-p3039-from-no229-squadron-completed-on-31-10-at-1150-pm/

One other glitch, Airfix on this and the 1/72nd fabric wing Mk I have changed the usual position on the wing to fuselage joint. I've not posted this up before, but as I know you are interested in this kind of detail....

quick aside, lots of great photos of the Shuttleworth Sea Hurricane in our walkround section, http://www.britmodeller.com/forums/index.php?/topic/76586-hawker-sea-hurricane/

The point in question is well shown in several other photos, but one for ease of reference

sh09.jpg

what I mean are the metal panels where they meet the wing, at that joint, the panels curve out slightly, very visible here due the way they catch the light, looks at the bottom row of fasteners, especially where the two panels meet, you can see the outward 'flare' of the panels. I can see how you would think the panels were flat, as it's quite subtle. Compare with a Hase kit though. Well shows the difference in texture between the fabric and metal covered areas as well.

Not worth worrying about for the non-obsessed, but not to hard to fix if you are prepared to redo the fastner detail, which is overdone on the kit, as the real thing are not raised discs. A piece of thin wall tube of the right diameter pushed into the plastic works, and then a fie drill for the centre.

All then is needed is to fill the existing panel line and rescribe slightly further out.

This also shows the shape of the fabric panel, comparison with Airfix one will show something is not quite right, as compared with one of your pic from the infamous thread, and also shows the flat sided nature of the fuselage panels.

Note relative positions of the rear metal panel middle fastener to the fabric one.

Airfix-Hurri-6.jpg

sticking the 72nd fabric wing kit on the original print Scale Models 1/72nd drawings gives the same length error as doing the same with the 1/48th kit on the 1/48th drawings, and my xeroxed up 1/48th drawings.

I'll get the camera out later for this.

Now, comments on paper stretch, plans varying and the like are all well and good, but the bottom line is that there are errors in the Airfix kits, and these are visible from photos, so a small length error is quite possible (and actually not visible) where the other problems, like the side panels, spinner and wheels are.

there is also the problem the thick trailing edge, thick Rotol spinner backplate, (easy fixes) and one piece ailerons, which is tough, though Basilisk did it,

To sum up, Airfix's A team did the Spitfire Vb/I kit, the B team did the Hurricane.

Personally, I wish I'd nit picked the 72nd fabric wing kit properly (not 'my' scale) as if I had I'd have blinkin' well taken the train to Margate and told the design team the problems...

more later

T

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I cannot understand why at this stage after so much discussion of the correct use of drawings that some people still seem to think that you use them as templates over which to lay parts or to make parts. I can understand people who have had no exposure to the design process doing it because they would be unfamiliar with instructions like "Do not scale". They would also be unfamiliar with the processes in which the overall general arrangement drawings of parts and whole assemblies of components are turned into shop drawings for the fabricators. They also seem to be unaware that the final form of the object is determined by the many many individual discrete components which are all separately designed, drawn and fabricated items that go together to make it.

The simple reality is and always will be that a technical drawing is just a series of construction instructions put into visual form which is why the dimensions etc. are clearly given. The fabricators are not expected to just overlay a bit of metal on them and mark out where to cut in pencil or some such. The same applies to the Bentley drawings which are really just a detailed depiction in line form as is a painting by an artist of the photo-realist school. If you want a realistic model you take the original dimensions as given on the appropriate drawings and calculate what they will be in your chosen scale of building and go from there.

The other thing which still seems to escape people is the clearly demonstrated capacity of paper to distort in the printing process and for any subsequent copies made of that distorted drawing to be further distorted by the method by which they are produced. These days the process is all done on computer software but the principles applying to paper copies are still the same. And paper copies are still produced and used for quick reference but no one with any understanding is using those as simple templates, so why are some modellers still clinging to the idea that printed drawings no matter how beautifully done are safe templates for accurate modelling.

Edited by MilneBay
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fine Malcolm

You are making the same point, again.

The safest approach is to use the measurements and other important data actually printed on a drawing not the drawing on its own. The Bentley drawings no matter how detailed are simply a line drawn picture of the aircraft not a guide to construction. One cannot guarantee that any drawing will not be distorted by the printing and copying process due to the nature of paper. I can understand the attraction of simply placing a kit component over what purports to be a drawing in the scale one is building in but it simply isn't a safe means to verify whether that component is correctly depicted.

please explain this

Using a widely accepted Hurricane dimension, the wing span, which is 40', in 1/48th is 10 inches, or 254 mm.

There have been numerous post here about being wary of drawings, how way should one be if the drawings when measured give the correct dimensions?

OK. lets see. 2005 Bentley

AF%20Hu%20wings%20on%20plan%20DSCF0288_z

The camera distorts, but this is very close match, especially given the relatively large size involved. The underside view on this panel is the same. Is this reasonable to assume this at least is close enough? If you have the plans, please try this at home.

The Airfix wings measure 10"/254mm as well.

so.... this is cobblers?

the plans match a given dimension within say, 2 scale inches, over 480 scale inches?

chance? random? Irrelevant?
For engineering, I see your point, for a scale model, they are made as scale plans, on which ruler and plans match on a given actual dimension within a very small error?
And the shape looks like photos.
Drawn by a reputable draughtsman, who specialises in aircraft, from the DIMENSIONED MANUFACTURING SUB ASSEMBLIES
as described in the cutting below
HurricaneBentleynotescrop_zpsc6a2675f.jp
I don't expect them to be 'perfect', but they are the best we have,
the relationship between panel lines and shapes on the drawings is consistent with the study of many photos,
and as I have tried to point out, in my post above, the new Airfix kits have errors that are plainly visible from photos.
The plans and photos agree, a major given actual dimension and the plans agree to within a small error, (and we still don't really have a good overall fuselage dimension.)
the kits don't.
As noted in the cutting, there are some bloody awful Hurricane plans out there, in respectable books, it should be noted on which the Airfix 1/72nd Hurricane IIc was based, and matches those well, which is why its a caricature.
How about instead of absolutes, the focus is on relative error, How close is 'good enough'
right, it's late, can I end on a request, I asked at Hendon if it was possible to measure P2617, their Mk I Hurricane, this was given a tentative positive answer.
what are the tools, techniques and pitfalls of measuring an existing airframe, and I'll go and measure if it I can.
TIA
T
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