A question for my fellow British Spitfire aficionados...

[packardpursuit]

Can anyone provide the proper British name or designation for the bubble-like cockpit cover which replaced the early flat-sided sliding hoods on "high backed" Spitfire variants? IIRC, by Mk V production , these had a true bubble-like feature, which I suspect was result of a "free-blown" type of Perspex manufacturing process (?).

I've noticed too, where many are now referring to that type Spit hood as a "Malcolm hood". Would that be correct?? I'm aware of the British-American historical connection of the Malcolm hood to Mustang development, however, was wondering if there is also a closer shared historical context between it and the earlier Spit's hoods? I suspect there is.

To what end? you may ask.  I'm trying to tie down nagging loose ends raised by long held popular historical notions compared to dateable photos and/or reliable historical documentation, which suggests the former may be largely legend/myth, etc., and/or possibly true in a general sense but misleading towards propagation of erroneous historical conclusions.

 For example: Is there a difference between a "360 deg. clear vision hood" (early designation for P-51D's original -2 type canopy) and later -6 type (a true) "bubble" feature canopy? For me, that question inspires others, such as: What aircraft first wore a "360 deg. vision type hood", clear or otherwise?? What aircraft first wore a true bubble-type canopy cover, clear or otherwise??

Would love to entertain anyone's thoughts and suggestions.

Thanks in advance,
charlieman

[MarkM]

To my knowledge there were 3 types of canopy hood fitted to the spitfire.

The early spitfire had the ‘straight edge’ canopy, mk1a onwards had the ‘Malcolm’ hood and the later Spits had the ‘Lobelle’ type. This one was a fully airtight canopy for the pressurised system they ran for high altitudes.

[bjrn]

With regard to which aircraft first had a "bubble" type 360° hood, the Vickers Wellesley is a candidate.

[packardpursuit]

Wellesley?  I could sure see why one might think so! I was thinking Westland Whirlwind, myself, but your pick seems earlier. HOWEVER, do either have "bubble canopies"??

AT this point I'm thinking first a/c to wear a true bubble type was Spit Mk V.  I could be wrong. Again, I'd appreciate some correction

IIRC, prototype and initial production Spitfires had a straight line top profile ( windscreen to headrest). Sometime later (still pre-war), profile was altered to provide more headroom overpilot's head, but sides were still "flat". I believe this canopy also included an oval shaped side vent on the port side, and continued thru Mk ll's. With Mk V, we see  free blown "bubble canopy" features and no side vent.   Is my understanding correct???

From a modeler's perspective the earlier types can be "pulled" over a simple form rather easily.   Free- blown types present some negative area issues that might not do as well, either pulled or vac-formed?

[dephela]

What aircraft first wore a "360 deg. vision type hood", clear or otherwise??

Mitsubishi A6M "Zero flew in 1939 with a "bird cage" 360 degree view canopy.

[packardpursuit]

A6M a good candidate too, but again, is it an actual 
"bubble" feature?

My point being 360 deg. vision capability does not necessarily define a "bubble canopy". Nor does high-back Spitfire's  free-blown nature automatically equate to being a 360 deg. vision hood.  From what I can tell from period photos Spitfires of Mk v and later, the bulged nature is from the circular nature of the canopy, at max cross-section, when viewed from front/rear.

I am of the opinion it is the nature of the bubble feature, itself, that allows the pilot's head to lean out to look downward, or even turn/look rearward, affording greater all around vision, despite the a/c's high-back.   Later, when the fuselage rear decking was lowered (beginning with Mk XVI?), the one-piece blister (also circular at max x-section) provided slightly better all-round visibility AND faired the windscreen into new lines of fuselage.

Comment??

[Rekitus]

I think the Spit was the first to build a canopy from one acrylic panel
and the idea got a bit bigger on later p47 and p51 models.
that part of the question may be best answered by looking at the F4 corsair.
it seems the idea of a single panel bubble caught on.

I never thought the Spit had 360 vision because there are mirrors mounted up high.
so the pilot didn't need to look over his shoulder.

the advancement to modern bubbles had a turtle deck in the way
of wide open sight lines.  The open cockpit airplanes like a p36
are an example of 'ordinary' airplane layout. the early mustangs
had a turtle deck... the greenhouse on the zero is where I'd look
for reasons to explain what planes were leading examples of the path to
wide field of vision for pilots.

[Prosper]

Hi Packard, I don't know if this adds anything useful to the discussionl:

Transparent acrylic came from Germany and was patented as Plexiglas, but ICI in Britain came up with an economically viable mass-production process and patented it, calling the product Perspex.

R. Malcolm Ltd made aircraft parts, and they came up with the blown Perspex hood. I don't know if Malcolm made the flat-sided-but-curved-top Spitfire hood. The Speed Spitfire of 1939 had a long moulded or blown windscreen, and the Mk.III was tested with various cockpit canopy types including a blown hood. A blown hood was tested on a Mk.V in April '42 and found not to affect the maximum speed. As a type, the Mk.V seems to have acquired a blown hood as standard somewhere throughout its long production life - p'raps somewhere in 1943 at a guess. I'm (almost) certain that as a youngster I read in 'Scale Models' magazine that the Malcolm hoods fitted to British Allison Mustangs differed slightly from one another because of the free-blowing process. At what point blowing became moulding I don't know, but presumably the early flat-sided-but-curved-top Spitfire hoods must have been constrained in some way, as if blown into an open-topped frame of some sort. And the non-catenary curves of later Spitfire hoods seem to suggest a female mould.

Stephen.

[Arnold S]

All I know is that Sam Wainwright from its "A Wonderful Life" had something to do with them! 

[packardpursuit]

I want to thank all who have contributed thus far. I have come to a bitter conclusion, though not fatal, AND I do want this discussion to continue. I would really like a heads-up to documentable evidence.

Here is a link to a similar discussion that I feel is worth a look. Some really great early Spit visuals, though cannot agree to the offered description of individual canopy types.  I'm well aware that common usage terms are not always technically or historically  driven.

https://ww2aircraft.net/forum/threads/spitfire-canopy-types.51336/

Prosper-  I had to look up that interesting word! "non-catenary".   Bing AI first sent me to a description of a gender type.  By going with "catenary" it described a line that is formed when a rope, string , chain, or wire is allowed to hang from two points. It showed illustrations of what I understand to be as  being parabolic lines.  So I'm thinking  non-catenary = not parabolic. 

I'm of the mind that Spit canopies changed with pilot's experiences and feed back.  Perhaps  Oachim's Razor applies?  Abject SIMPLICIYY of the hood is evident in it's first "flat top and sides" form..  This shape is relatively easy to  form with heated Perspex sheet  draped over simple wooden form (possibly covered in felt to avoid scratching the soft plastic).  Latter type. as seen on Mk I, Mk Ia, and Mk II's aloo seems a simple draping and (now) pulling procedure modified from the first method. So the manufacturing process could have been escalating.  Achieving actual blown features may require different approaches and/or considerations all together.