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1/72 Hurricane Mk I: Arma Hobby, my way.


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I'm opening a new W.I.P. topic while my work on the 1/72 Spitfire Mk.XIVe is slowly progressing toward (hopefully) a happy ending and BEFORE the Spitfire devil possesses me again in the form of a Mk.XII build.

I bought the Arma Hobby Hurricane Mk I some months ago in the hope of building it with minimal modification. As it happens I started to build up info, pics, books and really I could no more consider an out-of-the  box build. Worst of all I put my hands on a copy of Arthur Bentley's scale plans (considered to be the most accurate out there) and here I start this WIP. Please consider it as a guide to some modification work which is not really necessary, but could be an improvement of the still beautiful Arma Hobby kit.

I sincerely hope not to be misleading to the reader so I plea for some help by contributors like Troy White who know a LOT more than me about Hawker Hurricane.

I start with a comparison between the Arma fuselage and the Bentley profile view

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as well as a measurement of the fuselage length with my faithful Mitutoyo caliper

 

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I do not have the original 1:24 plans and I make reference to the scaled-down plans of Model Aircraft Monthly (november 2005) In reducing the size of the scan I took care to respect the dimension of the RAF roundels depicted in the plans (gives you the right proportion for both x and y directions).

The resulting measured length should be 113.95-114.00mm- with all of the approximation, it seems that the fuselage is slightly long (0,75mm?) More on this argument later.

With reference to the first picture, the main difference in profile between Bentley (B) and Arma (A)

could be summarized as:

-"hump"height (B is higher)

-"hump" shape (A has a recess for the closed canopy which doesn't exist on the real a/c

-upper engine cowling profile (B is more convex than A)

-lower fuselage depth (B is deeper than A)

-tailwheel fin shape (the B fuselage being deeper, its slope is less than in A)

-fuselage spine (A is more arched than B, being slightly concave).

For your pleasure, in the next post I'll examine these points one by one.

Edited by steh2o
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Let's start with  the hump height.

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Aligning the fuselage's cockpit sill to the drawing line (I use squared mechanical parts for that) it is pretty clear that the hump was deliberately cut in height to allow clearance for the sliding canopy element. As pointed out by Troy White in a very early review, the hump should be higher by about 0,3-0,4mm.

If you compare the "knee" between the sloping spine and the hump in A and B, you can see that A effectively truncated the slope at a lower level than due. This will help in the correction phase (had they chosen to lower the spine overall and respect the position of the knee would have been very hard to correct). The cutout for the canopy part is very evident. Here, Arma could have done better (providing an optional part f.a.e.).

Let's have a look at the nose section

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In the photograph the fuselage is aligned to the panel lines near the windscreen and rear exhaust opening. I tried to center the photograph perspective to this last line too. It is rather clear that the engine cowling perfectly follows the Bentley plan in the lower profile. There is a discrepancy in the upper profile, B having less slope in front of the windscreen and a having a more pronounced curvature in the top engine cowling panel. This discrepancy is difficult for me to understand. Knowing that Arthur Bentley based his plans on actual engineering drawings, I tend to trust him. The fuel tank cover panel is a simply arched sheet metal (providing a straight line in profile) which position is constrained by the instrument panel frame at the rear and by the firewall at about 3/4 of its length on top (see sketch below)

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Now, I believe that Bentley had access to quoted drawing of the tubular frame, instrument panel, and firewall frame, so the position of the thin blue line in the sketch should be unambiguous.

From Arma point of view, there is this picture published shortly before the appearance of the kit

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In which they show how the outline of the cowling was matched to the outline of a real aircraft!

If we now overlay Arma+Hawker (above) and Bentley we have the following

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Again, the profile discrepancy! Worst of all, there is a distinct difference in height at the firewall itself, which should be a very precise reference for fuselage height. In 1/72 the difference is a few tenths of a mm and can be disregarded. I decided to adjust the cowling profile to the Bentley drawing because that area still requires a major corrective action due to an insufficient fuselage width (more of this later) and this profile correction comes almost free.  If I'm not happy with it I can file it down to the original Arma profile when the fuselage halves are assembled together.

The above picture shows other interesting points. The lower fuselage profile behind the radiator seems much deeper in the B drawings than in the real airplane. Why?

Look at this other overlay (B vs real a/c)

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And this one, too

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The overlays are done with tele-photos which have a limited amount of distortion; they are obviously not 100% accurate but show anyway some discrepancy between Bentley plans and real aircraft (you decide if true or not)

-fuselage depth of the real aircraft seems less that in Bentley's profile

-ventral fin front slope is more accentuated than in B's

-spine is more arched (concave)

... and these are exactly the features evidenced in the comparison between A & B, see below

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It is clear to me that Arma matched its design to photographs of the real airplane; it is also clear that this design and Bentley's work have some discrepancies; it is also very clear that you can consider those as minimal and disregard them.

Going back to the "A vs B vs Hawker" overlay above, it is clear that the three match almost perfectly in the nose lenght, from windscreen to propeller, so my assumption here is Arma=Bentley in the nose area, except for the upper cowling profile.

If I align the A fuselage to B behind the propeller, I get

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three panel lines DO NOT MATCH: front of the exhaust opening , rear of the exhaust opening, windscreen.

If I match the windscreen line

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...the three panel lines match Bentley's and we have an interesting discovery: the front, conical part of the cowling starting from the front of the exhaust opening  is too long by about 0.3 0.4mm. This is confirmed by measuring the distance between propeller base and exhaust opening. This can be easily corrected, good news!

This is almost all about the fuselage profile.

In my W.I.P. I'm going to modify the following:

-reduce length of the front cowling cone

-reduce the overall fuselage length to a value closer to the Bentley's profile view

-adjust the hump height and fill the  horrible cutout

-modify the top cowling profile

-possibly modify the fuselage depth (I'm still not convicted who wins here, Arma or Bentley) but keep the ventral fin as it is (angle seems favorable to Arma)

 

Next I'm going to take a look at the fuselage plan view, wings and horizontal stabilizer

Edited by steh2o
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Just a magnification of the  overlay above in the windscreen area, angles of windscreen cockpit sill and panel lines match well, and the fuel cover panel seems to match the Bentley lines (even if this is a Mk.II it should be the same).

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Again, this is no proof and has MANY approximations but the angle seems in this picture more favorable to Bentley's work

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I think the same; moreover this technique requires to adjust very thoroughly distortion of the reference picture. Though, I think that it can provide some hint of what is right and what is not, at least in quality if not in quantity. Today's kit designers use more and more this technique, but it has to be supported by engineering drawings to be accurate enough.

As I say in the text, I'm proceeding in my build looking more at Bentley's drawings than at Arma's!

 

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I measured some features in the plan view. Please note that

-the measurements taken on  Bentley plans are subject to error due to scaling down a printed 1/48 copy and due to my eye! In the photographs below I show what my caliper reads after the measurement of the particular feature shown.

-the measurements taken on Arma kit regard MY particular copy and may vary.

Let's start with some key fuselage features

Fuselage width at the cockpit, about 14mm full-width

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Canopy width at its widest point (closed) about 8,5-8.6mm

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Arma fuselage at its widest point

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 Arma at the instrument panel

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Something is not OK in my sample: looking at the photograph above, it is fairly clear that the fuselage width is fairly good at the hump position, then squeezes down by about 0,4mm instead of increasing to 13.9-14mm.  The cockpit's canopy sill lines are strongly convergent and they should not be. Perhaps my sample is distorted but still the engine cowling lacks material to reach the correct width. This point has to be modified.

 

Arma maximum canopy  width (measured over the canopy rails

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Slightly more than due, but it could be the rails are too prominent

 

Resuming what I see:

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Green: I like

Red: I don't like and I want to correct

Paler green: acceptable

 

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If you got the Bentley plans from the original publisher then there were faults in the copying: the original 1/72 ones published in Scale Models are accurate, and the faults in the reproduction are one reason why he made these plans available directly from himself.

 

 

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Hello Graham, I'm using the ones of Model Aircraft Monthly, november 2005. I understand that basically the plans went unchanged over time and there could be some trouble with proportion in printing. I addressed this point checking some known elements like roundels and wingspan so I hope that they are OK within a +/-0.2mm which is close enough in most cases.

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On 08/03/2021 at 17:28, steh2o said:

I make reference to the scaled-down plans of Model Aircraft Monthly (november 2005) In reducing the size of the scan I took care to respect the dimension of the RAF roundels depicted in the plans (gives you the right proportion for both x and y directions).

the original printing of the Bentley plans was in Scale Models magazine August,(two pages, main plans)  September(1 page,  Sea Hurricane and other details) and October 1980(internals) .   The August issue seems harder to find.   

 

 

two things that Arma  missed,  small bulges on the UC doors, and the distinctive flat triangle made by the engine bearers between the main spar and the nose when it curves up.   The wing tips look a bit thick. 

 

At least two of the Arma Hobby team are members,  @GrzeM @Wojtek Bulhak   who may find this interesting.

 

3 hours ago, Graham Boak said:

If you got the Bentley plans from the original publisher then there were faults in the copying: the original 1/72 ones published in Scale Models are accurate, and the faults in the reproduction are one reason why he made these plans available directly from himself.

 

the ones above are the 2005 Model Aircraft Monthly one done as fold out to 1/48th.   Despite much talk of revisions, the only change I could spot is the proportion on the inner red portion of the upperwing roundel.

I know there were distortions in some reproductions though. 

 

I'll add more later if anything come to mind.   

 

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My idea is showing a way to enhance the still beautiful Arma kit; on with some work then!

The front cowling cone is too long

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I reduce its length a bit being very careful to keep the cut as straight as possible

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Right side done: I aligned the fuselage with the aforementioned panel lines, then used the squared aluminum block as a reference for the cut, while the squared copper block is a reference of the wing root leading edge. Remove the fuselage and...

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... a very good match.

Same thing for the left side, cut and file the front fuselage lip...

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And again a good match.

Now it's time to address the upper cowling profile shape (in the photograph above the left side is still modified).

To do this, I applied some upwards bending force to the area behind the ehausts opening, first the left fuselage, comparing it to the plan until the profiles match.

LHS and RHS fuselage halves are put together to show the difference (I accentuated the LHS border with a black marker)

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Now bend the RHS fuselage

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And the result is quite good at first sight.....

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...but consider that the bending raises the profile affecting the plan view and you find yourself with...

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But this is no problem because the next thing you want to do is.....

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....bend the fuselage halves one time at the back of the cockpit area outwards to get this....

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...and then do this....

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...to get this...

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....which at the end produces...

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which is fairly good!!

-profile matches;

-fuselage width is OK

-fuselage sides in plan are straight instead than bottleneck shaped

-canopy rails are much more parallel than before.

Next: I must fill the 0.5mm gap!!

Edited by steh2o
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20 minutes ago, Troy Smith said:

the original printing of the Bentley plans was in Scale Models magazine August,(two pages, main plans)  September(1 page,  Sea Hurricane and other details) and October 1980(internals) .   The August issue seems harder to find.   

 

 

two things that Arma  missed,  small bulges on the UC doors, and the distinctive flat triangle made by the engine bearers between the main spar and the nose when it curves up.   The wing tips look a bit thick. 

 

At least two of the Arma Hobby team are members,  @GrzeM @Wojtek Bulhak   who may find this interesting.

 

the ones above are the 2005 Model Aircraft Monthly one done as fold out to 1/48th.   Despite much talk of revisions, the only change I could spot is the proportion on the inner red portion of the upperwing roundel.

I know there were distortions in some reproductions though. 

 

I'll add more later if anything come to mind.   

 

Thank you for the heads-up Troy! And welcome to this thread!

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Hello again!

Some progress.... I thought that this Hurricane could be a relaxing project but it is not.

Here the process to fill the cowling gap: wanting to keep the alignement pins/holes  functional, I proceeded by producing a couple of 1mm holes (spaced as the top cowling pins)  in a 0,25mm-thick styrene sheet then roughly marked the fuselage profile with a pencil.

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Using the first profile as a reference I generate its twin

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 Then I tapered the front part of both elements and glued the first one to the LHS fuselage

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Then I took the LHS fuselage, inserted the second styrene wedge (guided by the pins) applied the RHS fuselage and glued the second wedge to the RHS fuselage only.

File to shape the upper contour, and add reinforcing CA+flour

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Not bad, the junction line will be refined after gluing the fuselage halves together

Let's check the fuselage length after trimming the nose cone

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I have lost 0.4mm already.

Careful dry-assembling of the fuselage and the horizontal stab and a bit of sanding of the rudder post area...

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Still an optimal fit....

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And the fuselage is now acceptable with Bentley's dimensions

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Hump correction.

That's quite unnerving because I had to work in close proximity to the fuselage spine and the very delicate rendering of the fabric effect there.

Arma cut down a bit the horizontal part of the hump keeping the right slope for the fuselage spine. So all is needed is restoring the correct height and extending a little bit the sloping part toward the cockpit. I choose to do it in the following way:

-first I defined the cut position with a pencil (vertical line); the small horizontal line is the level at which the side wall of the hump structure turns from flat to curved

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Then I cut with a fresh razor blade (so that no material is removed in the operation), stopping at the horizontal mark

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I've bent outside and up the flap so generated until reaching the correct hump height

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I repeated the operation for the other fuselage half and when happy with the hump height  I froze the new position with MetilEthilKetone (any other styrene cement will do). I finished up with the correct height but as a side effect there is a gap on top and a stepped side

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The gap was filled with a thinned-down and holed-through (to conserve the pin reference) sprue tab. The steps were sanded down to restore the right shape.

I filled the step behind the headrest with 0.5mm styrene sheet cut and filed to match the missing part

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Glued in place and sanded flat with the kit's hump

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the side steps required a bit of filler, here is not yet sanded flat

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A look at the side profile now:

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Bentley-zation is progressing nicely! Now I have to care the fuselage underbelly issue.

 

Edited by steh2o
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When comparing  it to photographs of the real airplane and to the Bentley's drawings it seems that the kit's lower fuselage panel it is too flat toward the radiator instead that gently curved. The same consideration applies to the panel just behind the radiator housing. We then can adjust the fuselage depth by simply bending down and curving a bit the lower fuselage panel. Because this is a very small quantity (0.3mm?) over a width of about 7mm, the bend doesn't significantly reduce the fuselage width, it simply introduces a tiny gap to be filled when joining the fuselage halves.

Here the result on RHS fuselage half and a comparison  with the untouched LHS (black-marked to better show the difference)

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Here below they are both modified

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Obviously this action has its consequence...

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....now the  fuselage has a mild curvature, while the underwing panel is dead-flat.

I did what follows...

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Now the fuselage depth is corrected according to the drawing and the curvature seems to match the photographs

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To keep everything in place, the interior was reinforced with a plastic sheet ordinate reinforced with sprue sections and much CA+flour (my favourite recipe...) The RHS fuselage keep in shape the LHS one through a couple of styrene protrusions

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Good! Next step: correcting the fairing near the carburettor intake, as per Troy indication

 

 

 

 

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Following the advice of Troy, I modified the area in front of the main wing spar which in the Arma kit is represented as a curved wing-to-fuselage fariing. In the real a/c this fairing has a more complex shape due to the fact that it covers a V-shaped reinforcing structure connecting the main wing spar with the engine bearer structure.

It is rather simple to modify the Arma underwing part to get a better shape, here following some pics showing the procedure I applied.

The key point to a successful modification is having the main spar (front of the wheel well) glued to the lower wing part because you will soon cut away a part of the wing-to-fuselage fairing. The main spar will keep the remaining parts in the correct reciprocal positions during the operation.

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Now it's time to use the faithful razorblade and cut away the wing to fuselage fairing using the two panel lines as cutting lines

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Here is the result: the two parts are neatly cut while the wing and the center panel keep their reciprocal position thanks to the main spar (not so neatly cut, the rear part of one would not separate from the spar and was broken, hence the glue to restore it to its original form).

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Now, more surgery: you have to divide the fairings according to the diagonal line defined (in the real a/c) by the V struts underneath

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Now, you I re-attached the leading edge of the fairing in its original position: this is easily done because the razor blade cut does not substantially modify the shape of the cut elements. The re-attached parts fall more or less in the same place as before the cut!

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In the real a/c the triangular panels are almost flat and lay in the same plane as the centerline panel surface. I bent the panels to more or less a flat surface, then I used a fingernail steel file to really flatten them at their final shape.

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At this point, the triangular panels can be re-attached this way:

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The fit is very precise, and you get the flat underside and the "step" so evident in some photographs

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The inside part has this look now: it will be reinforced as usual with CA+flour

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Finally, the step is filled with epoxy putty; at a later stage I will sand it a bit to get a more rounded edge

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And it's done!

At this point I think I managed to adjust all of the major shape issues to transform the Arma little gem in a Bentley-compliant thing.

In the next post, I'll spend a few words and photographs about flying surfaces (which to my opinion are pretty accurate) then I will start the next level, that is detailing the model surface.

 

 

 

 

 

 

 

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A look at the wing; measurement here becomes more complicate, but it is still possible to check most of the relevant features of it.

Wing span:

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My copy of the kit has a span of 168,9mm, a 0,4mm difference to the 169,33mm figure for 40' wing span of the real a/c. Further measurement shows that the 0.2mm difference is better added to the wing root than to the wing tip and considering that the kit has one-piece top and bottom wings this is troublesome.

Here below is a picture showing the kit's wing aligned with the drawings at the tip and root leading edge:

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The lines of significant features in the drawing have been extended to show if big discrepancies exist with the kit's part.

The overall shape is fine; the positions of the wing joint fairing and of the inner aileron border are both pretty accurate. The gun ports look to be a bit too close to the fuselage; the landing light recess is too far outside; the wingtip panel line is too inwards and as a result the aileron seems a bit short at the wingtip.

I have checked some more figures according to the wing back/front view below:

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The gun ports seem to be slightly inwards (0.2-0.3mm), the wingtip seems too long by about 0.6mm and the aileron short by 0.4mm (averaging the error, I'll move the panel line 0.5mm outwards to compensate the aileron length issue)

The wing thickness: at the root should be 6,75, I measure 6,6, at the aileron inner border should be 5,0, I measure 4,93 at the tip should be 2,6 and I measure 2,65 (but the panel line is misplaced in the kit so it could be less). Take all this meaurements as approximate +/- 0.1mm; the wing thickness is in my opinion quite accurate.

Wingroot measurement at the joint position, half-fairing line

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Same measurement on the drawing, good match

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Aileron inner border, good match

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Landing light window position... no match

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The measurements I took span-wise are always referred to the wing tip; if I had to adjust the wing length at the tip, I would introduce a +0.2mm to all of these measurements (gun ports too inwards by 0,4-0,5mm, aileron inner border inwards of 0.2mm and so on...). If I want to adjust the span I have to do it at the root.

For sure, I want to modify the following:

-wing tip panel line position + aileron extension

-landing light position

-slight adjustment of gun ports (they're small in diameter and their position can be refined while adjusting the bore size)

I will evaluate the span adjustement but I'm more inclined to leave it as it is (the actual 0,2% less seems  quite acceptable considering that the error in the fuselage length is about 1%)

 

 

 

Edited by steh2o
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  • steh2o changed the title to 1/72 Hurricane Mk I: Arma Hobby, my way.

While my Spitfire XIV is decanting (when I'm nearly finished with a build I let the model alone for a week or two so that when I look at it again I can better catch what I like and what I don't) I re-started some work on the Arma Hurricane Mk.I

A couple of weeks ago I saw on Amazon an Airfix fabric-wing Mk.I selling at just 7 euros, and I felt compelled to buy it.... shame on me....

One of the first things I did after opening the nice Airfix box was a comparison of the fuselage with my modified Arma one, and with Bentley's drawings. Well... the two match very well, except again in length; Airfix fuselage seems about 0,8mm too long at the tail but everything else seems matching rather well Bentley's drawings.

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I risk saying that in terms of general shape and details, the Airfix fuselage seems much more accurate than Arma's one.

-"out of the box" the profile seem to match Bentley's profile much better (with the Arma fuselage I had to raise the engine cowling, spine and hump lines, deepen the lower fuselage, shorten the length by 0,5mm)

-the fuselage width is correct, about 14mm in the cockpit/main fuel tank area

-another shortcoming of the Arma fuselage is the  wing fillet leading edge , which is too abundant. Airfix is much more correct in this point, moreover it depicts correctly the trapezoidal engine bearer undelying the fillet ( I had to modify it).

Had I to start again, I would probably choose an Airfix fuselage as a basis... I will try to correct the length issue of the Airfix, and see if it's easily done as an alternate to the massive work involved in the Arma fuselage mod.

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What is really unnerving with Airfix release is the wing.

If Arma wing span is scarce by 0,4-0,5mm, Airfix is excessive by about the same figure... the upper wing half, I mean. The lower is at least 1-2mm longer (a well known defect). Currently, I'm thinking about a way to correct this but I feel this is not so easy. Would Airfix refine a bit the wing design, their MkI would easily be the  best on the market today.

In the meantime, I proceed with Arma wing adjustments:

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I moved the landing light inwards: this is easily done by slicing the wing leading edge at the inner frame panel line, then gluing the slice so obtained to the other side.

I then filled the misplaced panel lines with stretched sprue + CA. I filled the wing tip panel line, and extended the aileron by about 0,5mm. Later, I decided to cut away the entire aileron, because I noticed that Arma forgot to represent the aileron hinges. Having the aileron as a separate element allows adding them in a simpler way. Also, i flattened a bit the wing tip surface (it is too curved in front view giving the appearance of too thick a wing tip that Troy cited in his post-while on the real a/c it is rather flat) The new panel line will be very close to the original one, because it does not coincide with the outer aileron end but is slightly inwards.

 

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Here's a view of the wing's fairing leading edge. I pencil-marked the excess part in the Arma kit (it is even more than this, but I will refine it when the wings are glued to the fuselage). I will review trapezoidal flat area too after checking thoroughly the available photographs. Bentley (see above) shows the engine bearers being almost tangent to the fillet in plan view (so that it should exists an almost "vertical" part of the fillet in side view. I do not know if this is an exxageration or the real thing

 

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28 minutes ago, steh2o said:

Airfix fuselage seems about 0,8mm too long at the tail but everything else seems matching rather well Bentley's drawings.

It is too long, note the cut out in the rudder post is the right length.  The fuselage is an early type, different windscreen and no 2nd fabric panel on the starboard side.  It also lacks the curve at the bottom of the fuselage panels, which is a PITA to fix. 

This is about the 1/48 kit, but that is based on the same data used for the 72nd.  I now know Airfix do read here, and wish I'd gone over the 72nd fabric wing kit properly!! 

 

 

If you fancy something different from the fabric wing kit.... Read this

 

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1 hour ago, Troy Smith said:

It is too long, note the cut out in the rudder post is the right length.  The fuselage is an early type, different windscreen and no 2nd fabric panel on the starboard side.  It also lacks the curve at the bottom of the fuselage panels, which is a PITA to fix. 

This is about the 1/48 kit, but that is based on the same data used for the 72nd.  I now know Airfix do read here, and wish I'd gone over the 72nd fabric wing kit properly!! 

Hello Troy,

I didn't check the fuselage bottom panel, is it too flat?

I also did not verify the curvature of the fuselage panels but I think that a correction (like in the attached thread) should be feasible.

I suspect that correcting the Arma wing fillet leading edge will be a major pain in the back... so, overall my rating of the Airfix fuselage jumped sky-high!

 

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If you fancy something different from the fabric wing kit.... Read this

 

This is a very interesting thread I wasn't aware of, thank you! I'll finish building a fabric-wing in parallel so it's most useful

 

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Edited by steh2o
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It seems I managed to shorten the Airfix fuselage, it took me a couple of hours and I'm not totally happy with the result, anyway here's what I did

resized_3f53b028-57bf-4134-a00b-38a422d7

 

The first cut was effected on the LHS fuselage half. I cut vertically along the panel line with a saw, then scored around the stabilizer/fin fairing with the sharp tip of a #10 scalpel, and broke the fuselage as seen in the photograph. After cleaning up the ragged border of the rear element, I reduced the lenght of the forward element by about 0,6mm. Here I found some difficulty, because the Airfix styrene is quite soft and it is very easy to overdo. In fact my cut was excessive by about 0,2mm in some places and I had to compensate with styrene strips.

Another difficulty arises when you want to glue together the two trimmed parts, because the Airfix fuselage has a separate underbelly and it can't be aligned with the plans! I sorted out a solution: by dry fitting the fuselage halves and underbelly, and gluing a styrene sheet tab at the end of the cut fuselage to help in the alignement of the tail, I managed to glue with good accuracy  the new shortened LHS fuselage

resized_dc639840-9221-42fc-9f97-dbbdb480

 

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In the photograph you can see the RHS fuselage protruding by 0,5-0,6mm, and also the small gaps at the joint line (they will be filled later).

The joint line is reinforced with CA+flour, and the RHS fuselage is cut with the same method as above

 

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In the photograph I marked balck the area to be removed from the cut fuselage

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In this last photograph you can see the RHS tail part glued to the LHS fuselage. I choose to do this way because I was worried about the correct alignement of the stabilators, considering that the tail elements have a little dimensional mismatch here. Obviously  the choice of gluing to the forward fuselage is OK too.

Enough!

At this point I would like to adjust the fabric wing to the correct span and finish up with the usual parallel build Arma vs Airfix...

Cheers

Stefano

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Very interesting, looking forward to seeing how You deal with the wing.

 

Regarding putting flour in CA - doesn't that introduce a foreign material and just weaken the glue (similar to air bubbles)?

I advise using two-component epoxy or maybe even "sprue-goo", since both are fully homogenous substances when mixed from their respective components.

 

Regards,

Aleksandar

 

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Hello Aleks,

I like the CA+flour for the following reasons:

-when cured it is very rigid

-it doesn't detach from styrene

-it is still workable 

-the flour avoids CA running everywhere

-it can be built up in volumes if needed

To me is the favorite structural filler. I don't like that much epoxies and sprue-goo mostly because of their slower curing time. CA is always a winner for that. Buy obviously it is an individual preference, I feel comfortable with it!

Ciao

Stefano

 

 

 

 

 

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  • 2 weeks later...

Some progress on the Airfix fabric wing.

The main trouble here is the span of the bottom wing being greater than the span of the top wing (this late being slightly excessive by 0,5-0,6mm). Another point that need attention is the area around the gun panels, which should be metal instead of fabric (as represented by Airfix)

The common approach to the wing span issue is removing the alignement pins, gluing top and bottom together, then adding filler to the top wingtip to conform its size to the bottom one. Although the most immediate one, this approach leaves you with an excessive wingspan.

I have tried a different way that adjusts the wing span and conforms better the general shape of the wing to the Bentley's plans (I don't claim it to be perfect, simply it's better than the other approach in terms of accuracy).

Firstly I checked that top and bottom parts of the ailerons match in span. Then I removed them from the wings with a razor saw and scalpel

 

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Now, I verified that the upper wingtip, from the aileron border to the very tip is slightly too wide. By comparison with the plans it seems to me that the distance between the last rib and the tip is slightly excessive, so I decided to shorten the tip by about 0,25mm each

 

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I traced the excess with the caliper tips and evidenced it with a black pencil

After removal of these 0,25+0,25mm, the upper wing span becomes amost right

 

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Not the best quality pic but trust me, it is in the range 169,1-169,4mm, should be 169,33! Obviously the wingtip is now blunter than it was, but I'll take care of that when I thin down the trailing edge of the wing.

Now I paired top and bottom wing using the outer aileron border as the reference line, and traced the excess part of the lower wingtip, first left then right.

 

resized_18a84ad5-0273-4086-bcd8-bf138e3a

 

the excess is removed, left and right.

After checking the span of the modified lower wing, I'm left with an excess of about 0,6-0,8mm overall; the wingtips are now matched at the aileron line, so I have to shorten the wing somewhere to the inside of this line. I choose the space between the aileron line rib and the next inward one. Regarding this area, Bentley shows another rib here that Airfix did not represent... I'll investigate better in the detailing phase.

One  razor-saw blade has a thickness of about 0,13mm, so I coupled two of them in a staggered fashion and cut away the wingtip

 

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The first blade etches a 0,15 guide-line , the second widens the cut at  about 0,3mm This cut removes effectively about 0,3mm leaving sharp borders...

 

resized_5f8b4374-ec38-450a-bd01-9e09fe3f

 

...that allow a precise junction with MEK afterwards; I did my best to keep an even cut, but some filling is still required.

The operation is repeated left and right, and what is left is...

 

resized_76a7b673-5b13-4a46-adcd-640293d8

 

...a lower wing that matches the upper one at the right span of 169,3 +/-0,1mm.

Please note that I removed just the outer mounting pins on the lower half, leaving the inner pins in place.

 

resized_9b17374a-d5b3-43f4-9eda-9c9af1b0

 

here's a pic of the assembled wingtip. I need to thin it down a bit , but overall the match is very good.

 

It's now time to apply some putty; while at it, I choose the  dissolved sprue method

 

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Pour in Metyl-Ethyl-Ketone like there's no tomorrow!! When the sprue bits are dissolved to a muddy consistence, I proceed with filling the unwanted gaps near the wingtips. Then I pour a lot of the stuff to correct the wrong fabric panels. Finally, a drop of the stuff is added to the cowling tear-drop shaped fairings that have to be refined a bit (the moulding process used both by Arma and Airfix can't produce an accurate shape)

 

resized_17c88db9-d0e7-426f-97fe-e4bc38fb

 

That's all for today!

 

 

 

 

 

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The rear area of the centre section should also be metal.

 

The other problem with simply aligning the wingtips is that this places the upper and lower ailerons out of alignment, and ditto the gunports.  I was beginning to think that I was the only person to have noticed this, and were there two different standards of molding for this kit?

 

Remember to chamfer the wingtips downward from the outer panel, there is a distinct kink in the top line.

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