Airfix Mk.1 Spitfire -A view. Options

[John Aero]

I have just found time to have a look at the new Mk.1 and though it's ancestry, in that it is a derivative of the the old Mk V, is plain to see, there have been many changes.

I am using a mix of fullsize dimensions and the works blueprints based (unpublished)drawings I obtained from Arthur Bentley and I trust them.

The fuselage is very good and from the firewall back it matches on all points, windscreen ,door, rear of rear view panel etc. The rudder is of correct chord and shape, with the only very minor niggles being the shape of the fin/fuselage fillet and that the rudder hinge line is 0.5mm too far aft. The wing fillets are good and of the correct width.

I have long maintained that the nose contours(ie thrust-line) on these Airfix Merlin family Spits are too high and although some reshaping has been done the Mk.1 nose plate is still too high by .75mm. Ok most folks won't notice it.

The wings. In 1:48 scale the Spitfire wing at it's thickest point should be 7mm and this new kit comes very close. Shapewise, the trailing edge is very good.
The leading edge at the centre gun positions is a touch too "full" and again at the very tip where the nav light is. The wing root angles on model Spits are all different and these follow the pattern but not the drawings.
I don't like the silly fabric sag, but a film of filler will sort this . The panel lines are fine. The trailing edges though much improved will still benefit from thinning down on the insides.

The shape of the D.H. prop blades is good but the Rotol not so good and the Watts two blader should look the part when assembled but watch out for the tips sweeping back.

So as far as the basic shape goes, Airfix have done well and remember that this was done under the constraints of the old company and so as such it is not a new Hornby kit.

Just my observations.

John





This post has been edited by John Aero: Jul 11 2007, 08:53 AM

[Col.]

May I ask John, is that the new fuselage half on the left and an older kit part on the right?

[John Aero]

May I ask John, is that the new fuselage half on the left and an older kit part on the right?

Hi Coll

No both are in fact the Airfix Mk.V with a tamiya spinner, but are so similar to the new Mk.1 as to make little difference as an illustration on how much to reshape (as on the picture right side).

John

[peebeep]

I found with the Mk IX that the spinner back plate doesn't match the nose and requires the cowling to be re-shaped to match. I would expect the same thing with the Mk I. Thanks for showing what is required John.

peebeep

[John Aero]

I found with the Mk IX that the spinner back plate doesn't match the nose and requires the cowling to be re-shaped to match. I would expect the same thing with the Mk I. Thanks for showing what is required John.

peebeep

Note the Mk.1 nose has been reshaped a little but not lowered.

With the Mk 9 you need to remove some plastic from the bottom of the top cowl piece, but taper it, from none at the back ,to about 1mm off the front. Then reshape to the spinner. The Mk.9 wings also need thinning, so once more the greatest thickness is 7mm.

John

[Mentalguru]

Note the Mk.1 nose has been reshaped a little but not lowered.


John

?? So although to my eye, your photos appear to show that the spinner HAS been dropped to match your new profile (which looks great btw) you saythe above- Im confused...

Also, although your new shapes look really great, does this mean you have a knock on effect with having to change the line of the lower side panels- or are the yfine s they are?

[John Aero]

?? So although to my eye, your photos appear to show that the spinner HAS been dropped to match your new profile (which looks great btw) you saythe above- Im confused...

Also, although your new shapes look really great, does this mean you have a knock on effect with having to change the line of the lower side panels- or are the yfine s they are?

Sorry, I didn't make myself very clear. The pics are the Mk.V which does need more reshaping. The new Mk.1 has had some slight re-tooling done (by Airfix) but the thrust line has not been lowered (as it has in my example in the photo). I have just done a quick test on my Mk.1 and I've sanded of the top of the nose a little and taped the lower cowl in position so I can check the spinner backplate against both. At worst a thin sliver of card will restore the balance if you take off too much. On the Mk.1 you don't have to remove as much material as on the Mk.V, so beware. The Spit has a subtle curve between where the rocker bulges finish and the spinner backplate.

John

This post has been edited by John Aero: Jul 11 2007, 02:11 PM

[Col.]

I'm guessing the simplest solution is to remove the required material from the top cowl and add a sliver of plasticard to shim down the lower cowl corespondingly, thus getting the correct shapes and thrust line after a little extra filler to blend it all in?

[John Aero]

This is my recommendation for the areas to be thinned before assembly.

By the way the assembled shot is only taped togethether I don't glue them as then I would have to paint the bloody things!

John




This post has been edited by John Aero: Jul 11 2007, 07:55 PM

[Mentalguru]

One other small point John.

No inferences,

I really really rate Arthur Bentleys Spitfire drawings, just as I rate his P-51 Mustang drawings. Unfortunately, there is some sort of conspiracy against his work from certain quarters, I just dont understand why.
His Mustang drawings suffer the same as the Spit drawings in that he seems incapable (unless he has now done it) of splitting the different marks into seperate drawings, so making them extremely difficult to follow.
Having been to Arthurs house on a few occasions, I have a great understanding of the way he constructs his masterpieces, and am quite happy to go with his interpretations..

But- I have noticed that Arthur bases his drawings on engineering data, scale drawings, common sense, and mathematics, mixed with a strong understanding of aircraft parlance and design philosophy. But on the Mustang drawings, my "artists" eye saw a couple of outline errors on small detail, namely fillet curves and non structural items of airframe design. Blending is perhaps not his best talent, and I am wondering if the area at the base of the tail has suffered the same fate as similar parts of he P-51 drawings? Its almost as he gts his french curves and just joins things up..

So just because that curve doesnt match his drawings- are you sure the kit is wrong?

[John Aero]

One other small point John.

No inferences,

I really really rate Arthur Bentleys Spitfire drawings, just as I rate his P-51 Mustang drawings. Unfortunately, there is some sort of conspiracy against his work from certain quarters, I just dont understand why.
His Mustang drawings suffer the same as the Spit drawings in that he seems incapable (unless he has now done it) of splitting the different marks into seperate drawings, so making them extremely difficult to follow.
Having been to Arthurs house on a few occasions, I have a great understanding of the way he constructs his masterpieces, and am quite happy to go with his interpretations..

But- I have noticed that Arthur bases his drawings on engineering data, scale drawings, common sense, and mathematics, mixed with a strong understanding of aircraft parlance and design philosophy. But on the Mustang drawings, my "artists" eye saw a couple of outline errors on small detail, namely fillet curves and non structural items of airframe design. Blending is perhaps not his best talent, and I am wondering if the area at the base of the tail has suffered the same fate as similar parts of he P-51 drawings? Its almost as he gts his french curves and just joins things up..

So just because that curve doesnt match his drawings- are you sure the kit is wrong?

Hi

I believe that the kit is wrong because it also disagrees with the outlines in the Robinson drawings and with the outlines in some of the Supermarine drawings which have been used in some publications and the under rated Cox drawings. So I'll go with Arthur. I am not qualified to rate the Mustang drawings or indeed comment on them but so far I'm happy with the Spitfires. The fillet shape is quite minor.

Yes I have the very detailed "multiplex" drawings for the Spit, which I have no problem with as I know that they have been derived from works production drawings and I have sufficient measurements to hand to check.

Cheers

John

[Mentalguru]

OK= thats

Thanks for reassuring me John

Rich

[John]

Excellent review and a masterly summary of the kit's issues, if I may say so. As I've said before I bought 2 Tamiya MkIs about 14 years ago and one's still in its box! My feeling at the moment is that the work needed to produce a visually acceptable Spitfire MkI will be significantly less with the Airfix kit than the Tamiya.

John

[Jonathan Mock]

Yes, a top class constructive assessment Mr Adams.

[Mentalguru]

Whilst I have clever knowledgeable people in front of me talking about the Spitfire- what is the CORRECT shape for the main wheel bays?

[John Aero]

Whilst I have clever knowledgeable people in front of me talking about the Spitfire- what is the CORRECT shape for the main wheel bays?

This one is a difficult one. I spent ages thinking about the complicated geometry involved as the wheel has castor, camber and toe in and the angled pintle make the leg go from vertical forwards sweep, to rearwards hoizontal sweepback. Also how does the wheel lie in the bay? Then if you look at the door fairing ,it projects more at the front. But this changes as the oleo extends. All the engineering drawings show two staggered elipses.

Short answer, it's eliptical, cos I found a nice photo of a Mk.XII in a vertical bank which illustrates it nicely but I forgot to bring it home with me.

Cheers

John

[Edgar]

During my last visit, to the RAF Museum, I did a little research on the wing stiffeners, for the VA,VB, & VC. One of the drawings depicts the well as having two, overlapping, circles, with (presumably) a sloping wall between them. Obviously, this will form an ellipse, when viewed from below. Years ago, in the days when I built flying (well, some of them) models, I remember reading about how to mount a retractable u/c, and the hinge had to be mounted at an angle, which allowed the leg to enter the well, and lie flat. I would guess that the angle dictated that the wall had to be angled, slightly, to allow the wheel to enter, because the wheel would end up in a different position from its entry point.
Edgar

This post has been edited by Edgar: Jul 12 2007, 05:59 PM

[John Aero]

During my last visit, to the RAF Museum, I did a little research on the wing stiffeners, for the VA,VB, & VC. One of the drawings depicts the well as having two, overlapping, circles, with (presumably) a sloping wall between them. Obviously, this will form an ellipse, when viewed from below. Years ago, in the days when I built flying (well, some of them) models, I remember reading about how to mount a retractable u/c, and the hinge had to be mounted at an angle, which allowed the leg to enter the well, and lie flat. I would guess that the angle dictated that the wall had to be angled, slightly, to allow the wheel to enter, because the wheel would end up in a different position from its entry point.
Edgar

Well put Edgar, yes as the leg moves upwards there is also a rearwards travel so the resulting vector requires the bay to be "quint". which accounts for the extra leading edge projection of the door to fill the swept area.

John

[peebeep]

Shooting off at a slight tangent but relevant to the thread. I took this pic of the Supermarine S6 at the Southampton Hall of Aviation:



Is the shade of green used in the cockpit anything like that you might expect to find in early Spitfires?

peebeep

This post has been edited by peebeep: Jul 14 2007, 11:13 PM

[dylan the rabbit]

Shooting off at a slight tangent but relevant to the thread. I took this pic of the Supermarine S6 at the Southampton Hall of Aviation:



Is the shade of green used in the cockpit anything like that you might expect to find in early Spitfires?

peebeep

Don't think much of their cockpit wash either...