Spitfire Mk1. Differences between Mid and Late

[Tolga ULGUR]

1 hour ago, 19squadron said:

The Kotare is too heavy at the shank relative to the Chord.

 

the widest part of the curve on the trailing edge is much too high, and the long straight trailing edge from the tip to the widest part of the chord on the trailing edge [which contrasts with the much more symmetrical curve of the leading edge] is missing.

 

the edge of the leading edge follows the leading edge curve and crosses the blade at the shank end before the shank end becomes round to fit into the hub.

 

It's crude and has none of the quality of a real blade.

 

Thanks for this  @19squadron 

Yes, after examining it very carefully, I agreed with what you said. But I must admit that I didn't realize it until you explained it. Maybe my eyes are not good enough. Age also advanced.
Again, those who are not very meticulous about accuracy and whose eyesight is poor (like me) could not may notice this.
In fact, it should not be very difficult to produce an aftermarket product with today's technological possibilities. Maybe one man business producers can take action on this issue, of course, with your technical knowledge and support. (Forgive me if I forget any other manufacturers, but the first one that comes to mind is (Alistair from Aerocraft) Ali62

Edited December 31, 2023 by Tolga ULGUR

[geedubelyer]

I can't unsee that now. 

[Archimedes]

@19squadron Thank you for the images Simon. Yes, my post was intended to elicit further information so I appreciate the response. Despite the many highly useful images I am still looking at ‘apples and pears’ if you will because I am seeing real propellers which are painted, shown at various angles of incidence in varying lighting conditions versus a frontal view and one angle of incidence of a kit propeller. That being said I now do see the offset between the leading and trailing edges of the blade relative to their distance from the hub. As someone who spent a whole year designing propellers for drones in 3D CAD I do appreciate just how challenging these shapes can be to replicate at any scale.

 

Whilst I would hesitate to use the word ‘crude’ when it comes to Kotare’s 32001 DH propeller attempt, I can now see that it is not quite the blade shape of a real DeHavilland airscrew.  There are many factors that have to be borne in mind when producing a model of any subject. The propeller is probably the single most difficult shape to get right. As one moves from the hub to the tip and looks at the cross-sections, one generally moves from a circle at the hub through to aerofoil sections that are twisting all the while as one moves outward. One can burn hundreds of hours in designing this whether lofting it (as the draftsmen at Jablo, Hordern Richmond, Weybridge Blades, Rotol and presumably DeHavilland had to do) or doing it in 3D CAD (which is subject to the limitations of the CAD package). Kotare will have had deadlines to meet, a price point to hit and a profitability target they were aiming for. At some point someone in Kotare may have said: ‘OK that is good enough - stop work on the propeller blade and move on’.  That is not to make any excuses for anyone but it does now make me wonder what the Revell MkII and Tamiya MkIX propellers look like in comparison.

 

Thank you for providing this insight. It is one more of many that demonstrates just how hard the Spitfire is to get right for the model making community. Though the fascinating RAeS paper referenced below does not mention the propeller specifically, what it does do it demonstrate just how diligent Supermarine were in attending to fine detail of almost every facet of their design. 

 

RAeS Spitfire Paper

 

What this resulted in was in the Mk1 aircraft that could fly 40 mph faster in level flight, using the same power  than its compatriot, the Hurricane. 

 

Thanks once again Simon.

 

Kind regards,

Paul

[Archimedes]

And, one last point: Is the blade shape a deal breaker for me? It is not. 

 

Kind regards,

Paul

Edited December 31, 2023 by Archimedes
Duplicate post

[Pete Roberts]

Yes, I have to admit the propeller in a kit/kitset is probably one detail I tend to overlook, but I have to admit that after-market FW 190 prop is a work of art. The photos do show quite a disparity between the Kotare kitset DH prop and the real thing.

 

Maybe one for the aftermarket gurus, or maybe one for Kotare to do as a 3D print, like their exhausts. Yes, I know, I can hear some howls already - why didn’t they get it right first up. I think that has been covered earlier. And to me, it also falls into the ‘new research’ basket, ‘cause I reckon there is only so much research you can do before you have to put something out, actually do something, otherwise you spend all your time researching and never get anything done! How many times do we see research books republished as ‘Revised’ editions.

 

Contributors like 19 Sqn raise some very good points that hopefully a manufacturer takes on board and uses to good effect. Collaboration can be a powerful force, and we all benefit.

[19squadron]

4 hours ago, Archimedes said:

@19squadron Thank you for the images Simon. Yes, my post was intended to elicit further information so I appreciate the response. Despite the many highly useful images I am still looking at ‘apples and pears’ if you will because I am seeing real propellers which are painted, shown at various angles of incidence in varying lighting conditions versus a frontal view and one angle of incidence of a kit propeller. That being said I now do see the offset between the leading and trailing edges of the blade relative to their distance from the hub. As someone who spent a whole year designing propellers for drones in 3D CAD I do appreciate just how challenging these shapes can be to replicate at any scale.

 

Whilst I would hesitate to use the word ‘crude’ when it comes to Kotare’s 32001 DH propeller attempt, I can now see that it is not quite the blade shape of a real DeHavilland airscrew.  There are many factors that have to be borne in mind when producing a model of any subject. The propeller is probably the single most difficult shape to get right. As one moves from the hub to the tip and looks at the cross-sections, one generally moves from a circle at the hub through to aerofoil sections that are twisting all the while as one moves outward. One can burn hundreds of hours in designing this whether lofting it (as the draftsmen at Jablo, Hordern Richmond, Weybridge Blades, Rotol and presumably DeHavilland had to do) or doing it in 3D CAD (which is subject to the limitations of the CAD package). Kotare will have had deadlines to meet, a price point to hit and a profitability target they were aiming for. At some point someone in Kotare may have said: ‘OK that is good enough - stop work on the propeller blade and move on’.  That is not to make any excuses for anyone but it does now make me wonder what the Revell MkII and Tamiya MkIX propellers look like in comparison.

 

Thank you for providing this insight. It is one more of many that demonstrates just how hard the Spitfire is to get right for the model making community. Though the fascinating RAeS paper referenced below does not mention the propeller specifically, what it does do it demonstrate just how diligent Supermarine were in attending to fine detail of almost every facet of their design. 

 

RAeS Spitfire Paper

 

What this resulted in was in the Mk1 aircraft that could fly 40 mph faster in level flight, using the same power  than its compatriot, the Hurricane. 

 

Thanks once again Simon.

 

Kind regards,

Paul

Dear Paul

 

May I thank you for your very generous and kindly worded post. I concur in all that you say, except to add this. To me the Spitfire is the most beautiful and important aircraft ever to fly. Her lines are just sublime, which is a large part of why Spitfires elicit so much affection in so many. Add to that the fact that none of us today would be here, and have lives at all, without the contribution that the Spitfire made in 1940, which makes the Spitfire by far the most important and significant aircraft, of all time. I suspect that many feel the same.

 

 

To that end, of all aircraft, the Spitfire deserved the most carefully considered and designed kit in 1/32. The Eduard kit in 1/48 is very good and I was fortunate to contribute to the research for the MkI, II and V. There are a few niggles, the missing hydraulic oil tank on the manual undercarriage retraction aircraft, the electrical socket in the wing fillet on MkI's and a few other cockpit details, but other than that, it was nicely done, and importantly the fuselage, wing and the props were rendered with much attention. The Tamiya 1/32 Spitfire also has its flaws, most notably the clumsy rib tape on the rudder which is characteristic of all Tamiya kits, but the big Tamiya has a well-designed Rotol and above all a beautifully rendered engine cowl, fuselage, and most importantly of all, wing.

 

I am very familiar with J A D Akroyd's paper on the Spitfire and have read it many times. It concurs very well with all my years of research into the Spitfire and is essential reading to my mind for all who are interested in this beautiful aircraft. One of the subjects in Akroyd's paper is the very significant attention R J Mitchell attached to drag reduction, especially from the main plane. To that end surface finish and smoothness on both the top and bottom of the wings were critical and he went to great effort to make those surfaces smooth, both by flush riveting them, by filling over the flush rivets on the leading edges in front of the main spar and by designing all covers and access panels with accurate seals to be flush fitting. To RJ Mitchell's extreme chagrin, the first flights of the prototype K5054 were slow and failed to meet R J M's expectations, and other than by trying numerous propeller blades of differing pitch and chord, R J M objected to the fit and finish of the access panels on the wings. To that end, the Prototype was returned to the factory to have all the wing access panels removed where it was found the seals had not been properly fitted, causing those panels to fail to lie flush and so in protruding into the airflow, causing significant drag which was a major cause for the early lack of speed in K5054 test program. When the Spitfire went into production enormous effort went into following R J M's instructions to produce well-fitting flush Gun and Ammo box covers and all access panels.

 

What would R J Mitchell say were he to see the Kotare Spitfire then with all the gun and ammo box covers standing well proud of the wing surface? I have no doubt he would be horrified. Now inn wartime service, panels did get bent and it is possible to find the odd wartime pic with trailing edges lifted, but true fitting panels were also a maintenance issue for fitters because bent panels were not only drag-inducing but they could also be lost in flight - however, if you look at the Kotare kit you will see the gun and ammo covers are well proud of the wing around the entire circumference of each and every panel. That is not only an error, it is an error that belies the very essence of the philosophy and work that R J Mictchell, B Shestone and J Smith put into this beautiful aircraft.

 

Worse still is the awful wing tip shape that Kotare has given that kit. The original Supermarine drawings clearly show a compound curve of four radii in the wingtip, which was beautifully executed by both Tamiya in 1/32 and Eduard in 1/48. The Kotare wingtip is as ill-designed and poorly rendered as their De Havilland prop.

 

I am very disappointed by this kit, and I cannot accept that is a good representation of the Spitfire, or that it comes anywhere close to the standards set by both Eduard or Tamiya.

 

 

with all best wishes

 

 

Edited December 31, 2023 by 19squadron

[19squadron]

19 minutes ago, Pete Roberts said:

Yes, I have to admit the propeller in a kit/kitset is probably one detail I tend to overlook, but I have to admit that after-market FW 190 prop is a work of art. The photos do show quite a disparity between the Kotare kitset DH prop and the real thing.

 

Maybe one for the aftermarket gurus, or maybe one for Kotare to do as a 3D print, like their exhausts. Yes, I know, I can hear some howls already - why didn’t they get it right first up. I think that has been covered earlier. And to me, it also falls into the ‘new research’ basket, ‘cause I reckon there is only so much research you can do before you have to put something out, actually do something, otherwise you spend all your time researching and never get anything done! How many times do we see research books republished as ‘Revised’ editions.

 

Contributors like 19 Sqn raise some very good points that hopefully a manufacturer takes on board and uses to good effect. Collaboration can be a powerful force, and we all benefit.

Good original drawings of the De Havilland prop are easily available and could have been used to design the kit part very accurately and efficiently. Maybe there is space for " a "corrected" prop for this kit, but it would need to go alongside a corrected wing tip, and engine cowls as well as a better cockpit in my view. It is an expensive kit as it is when you consider other 1/32 kits from Tamiya and WNW were not only more accurate but came with engines too for similar money.

[Archimedes]

8 hours ago, 19squadron said:

Dear Paul

 

May I thank you for your very generous and kindly worded post. I concur in all that you say, except to add this. To me the Spitfire is the most beautiful and important aircraft ever to fly. Her lines are just sublime, which is a large part of why Spitfires elicit so much affection in so many. Add to that the fact that none of us today would be here, and have lives at all, without the contribution that the Spitfire made in 1940, which makes the Spitfire by far the most important and significant aircraft, of all time. I suspect that many feel the same.

 

 

To that end, of all aircraft, the Spitfire deserved the most carefully considered and designed kit in 1/32. The Eduard kit in 1/48 is very good and I was fortunate to contribute to the research for the MkI, II and V. There are a few niggles, the missing hydraulic oil tank on the manual undercarriage retraction aircraft, the electrical socket in the wing fillet on MkI's and a few other cockpit details, but other than that, it was nicely done, and importantly the fuselage, wing and the props were rendered with much attention. The Tamiya 1/32 Spitfire also has its flaws, most notably the clumsy rib tape on the rudder which is characteristic of all Tamiya kits, but the big Tamiya has a well-designed Rotol and above all a beautifully rendered engine cowl, fuselage, and most importantly of all, wing.

 

I am very familiar with J A D Akroyd's paper on the Spitfire and have read it many times. It concurs very well with all my years of research into the Spitfire and is essential reading to my mind for all who are interested in this beautiful aircraft. One of the subjects in Akroyd's paper is the very significant attention R J Mitchell attached to drag reduction, especially from the main plane. To that end surface finish and smoothness on both the top and bottom of the wings were critical and he went to great effort to make those surfaces smooth, both by flush riveting them, by filling over the flush rivets on the leading edges in front of the main spar and by designing all covers and access panels with accurate seals to be flush fitting. To RJ Mitchell's extreme chagrin, the first flights of the prototype K5054 were slow and failed to meet R J M's expectations, and other than by trying numerous propeller blades of differing pitch and chord, R J M objected to the fit and finish of the access panels on the wings. To that end, the Prototype was returned to the factory to have all the wing access panels removed where it was found the seals had not been properly fitted, causing those panels to fail to lie flush and so in protruding into the airflow, causing significant drag which was a major cause for the early lack of speed in K5054 test program. When the Spitfire went into production enormous effort went into following R J M's instructions to produce well-fitting flush Gun and Ammo box covers and all access panels.

 

What would R J Mitchell say were he to see the Kotare Spitfire then with all the gun and ammo box covers standing well proud of the wing surface? I have no doubt he would be horrified. Now inn wartime service, panels did get bent and it is possible to find the odd wartime pic with trailing edges lifted, but true fitting panels were also a maintenance issue for fitters because bent panels were not only drag-inducing but they could also be lost in flight - however, if you look at the Kotare kit you will see the gun and ammo covers are well proud of the wing around the entire circumference of each and every panel. That is not only an error, it is an error that belies the very essence of the philosophy and work that R J Mictchell, B Shestone and J Smith put into this beautiful aircraft.

 

Worse still is the awful wing tip shape that Kotare has given that kit. The original Supermarine drawings clearly show a compound curve of four radii in the wingtip, which was beautifully executed by both Tamiya in 1/32 and Eduard in 1/48. The Kotare wingtip is as ill-designed and poorly rendered as their De Havilland prop.

 

I am very disappointed by this kit, and I cannot accept that is a good representation of the Spitfire, or that it comes anywhere close to the standards set by both Eduard or Tamiya.

 

 

with all best wishes

 

 

Hi Simon

 

Happy new year to you and thank you for the well-considered reply. I have taken a look at the Kotare wing-tip profile in particular versus the Bentley drawings (Arthur describes these as ‘Roughs’). I don’t have copies of Supermarine originals on hand unfortunately.  I’d say the tip profile is a little too sharp and maximum span very slightly too far forward (Bentley’s Mk.1 wing planform is the smooth arc furthest right on this image (apologies all for the poor lighting on this picture). . 

 

The gun covers as measured by my micrometer vary between a scale 1/16” and 1/8” proud of the wing surface. This would have not been acceptable to RJM on K5054 as you note but under wartime conditions on production machines that had been subcontracted out? I don’t know. Morgan and Shacklady note the difficulties of assuring quality control particularly in the Mk1 series of aircraft. Is Kotare’s interpretation acceptable? Not for you, warranting a minor sand down and rescribe for me and possibly perfectly fine for many.

 

I can only agree with the ethos of how the Type 300 design was brought to fruition. Kotare are a start up and despite the presence of most of the old Wingnut Wings team, they do not have the financial latitude that WnW had to explore (e.g. spending a decade designing a 1/32 Lancaster). This is a new company’s first effort in quick-smart time and I am willing to give them some latitude for that. If we look at some of Tamiya’s early attempts at some subjects we find similar shape errors. Our alternative for a Spitfire Mk1a is the Revell kit which @thierry laurent has clearly shown requires a huge amount of effort to make something approaching accurate. 

8 hours ago, Pete Roberts said:

Contributors like 19 Sqn raise some very good points that hopefully a manufacturer takes on board and uses to good effect. Collaboration can be a powerful force, and we all benefit.

I can only agree with @Pete Roberts on his point regarding collaboration.  There is a vast amount of information about the Spitfire out there together with a great number of ’Spitfire Boffins; like Simon @19squadron who are able to advise. As RJM himself was well aware, the resulting quality of any endeavour is subject to three mutually opposing constraints: Scope, Time and Cost.  This was true of Supermarine then for the real thing and true for Kotare now. I am just going to get on with building this kit now. The most limiting factor in getting a good representation is not the kit: it is me. 

 

Thanks once again for your enlightening observations and I wish you all the best in 2024! 

 

Kind regards,

Paul

Edited January 1 by Archimedes

[DonH]

Hello all, I have compared a spare Tamiya wingtip with the Kotare version and they are an EXACT match in plan. I have not checked the curves/airfoil section (yet) but expect them to also match. By eye, they look an exact match in all respects.

Edited January 3 by DonH

[DonH]

On 1/1/2024 at 1:24 PM, Archimedes said:

 

The gun covers as measured by my micrometer vary between a scale 1/16” and 1/8” proud of the wing surface.

On another topic, I have run my finger over the gun covers and they are detectably proud of the surface, but in my opinion, only barely so, and I can't see it with my eye. Not disputing your measurements, I am just saying it is not significant to my naked eye. Worth noting that they are a different finish to the surrounding plastic (glossier?) that may accentuate the perception that they are raised. 

[19squadron]

2 hours ago, DonH said:

Hello all, I have compared a spare Tamiya wingtip with the Kotare version and they are an EXACT match in plan. I have not checked the curves/airfoil section (yet) but expect them to also match. By eye, they look an exact match in all respects.

 

           I disagree, the Kotare wingtip has a very simplified shape by comparison to the Tamiya. The leading edge of the Tamiya wingtip is entirely correct, the Kotare is not, and it spoils the delicacy and form of the Spitfire wing which is iconic.

Edited January 3 by 19squadron

[19squadron]

On 1/1/2024 at 5:24 AM, Archimedes said:

Hi Simon

 

Happy new year to you and thank you for the well-considered reply. I have taken a look at the Kotare wing-tip profile in particular versus the Bentley drawings (Arthur describes these as ‘Roughs’). I don’t have copies of Supermarine originals on hand unfortunately.  I’d say the tip profile is a little too sharp and maximum span very slightly too far forward (Bentley’s Mk.1 wing planform is the smooth arc furthest right on this image (apologies all for the poor lighting on this picture). . 

 

The gun covers as measured by my micrometer vary between a scale 1/16” and 1/8” proud of the wing surface. This would have not been acceptable to RJM on K5054 as you note but under wartime conditions on production machines that had been subcontracted out? I don’t know. Morgan and Shacklady note the difficulties of assuring quality control particularly in the Mk1 series of aircraft. Is Kotare’s interpretation acceptable? Not for you, warranting a minor sand down and rescribe for me and possibly perfectly fine for many.

 

I can only agree with the ethos of how the Type 300 design was brought to fruition. Kotare are a start up and despite the presence of most of the old Wingnut Wings team, they do not have the financial latitude that WnW had to explore (e.g. spending a decade designing a 1/32 Lancaster). This is a new company’s first effort in quick-smart time and I am willing to give them some latitude for that. If we look at some of Tamiya’s early attempts at some subjects we find similar shape errors. Our alternative for a Spitfire Mk1a is the Revell kit which @thierry laurent has clearly shown requires a huge amount of effort to make something approaching accurate. 

I can only agree with @Pete Roberts on his point regarding collaboration.  There is a vast amount of information about the Spitfire out there together with a great number of ’Spitfire Boffins; like Simon @19squadron who are able to advise. As RJM himself was well aware, the resulting quality of any endeavour is subject to three mutually opposing constraints: Scope, Time and Cost.  This was true of Supermarine then for the real thing and true for Kotare now. I am just going to get on with building this kit now. The most limiting factor in getting a good representation is not the kit: it is me. 

 

Thanks once again for your enlightening observations and I wish you all the best in 2024! 

 

Kind regards,

Paul

 

 

Paul

 

Again thankyou for your very aposite and generous post.

 

I attach pics of an "A" wing built in 1940 showing the wingtip. It the photo you can see how the leading edge curve is  produced to the wing light. Then there is a transition radius between the winglight to the mainspar and mainspar panel, and finally there is the leading edge radius from mainspar to tip. Three radii to the leading edge, there is then a radius to the trailing edge for a total of 4 radii to the wingtip. These very subtle cures give the wing so much of it's shape and character, both of which are absent in the Kotare kit.

[19squadron]

 

An original made in 1940 Spitfire wingtip.

[19squadron]

 

 

A technical drawing used to make new wings, drawn from the orgiginal Supermarine drawings where the wingtip radii are described in English text, to illustrate the photograph of the real wingtip in the previous post.

[19squadron]

                Here is the wing of a totally unrestored Spitfire R6915, showing not only the wing surface typical of anything but an airframe still in the factory, but despite all the age and use here, gun covers lying as they were designed to do, entirely flush with the wing surface - as I said this was both a design feature most carefully directed by RJ Mitchell and executed by Joseph Smith, but also a service issue which is why you might find the odd quiver on the trailing edge of an access panel or cover, but never on a leading edge. It was also for that reason a maintenance issue for fitters to ensure all panels and particularly leading edges were flush. The Kotare kit runs a coach and horses through R J Mitchell's very specific requirement and J Smiths execution in this matter.

Edited January 3 by 19squadron
addition of pic