Armoured glass

[Readie]

I'm having a look at the history of armour in fighters and will start off with armoured glass.
I know fighters had the front screen made 'bulletproof'. Whether it was cannon proof is another matter...

Does anyone know the answers to these questions please?

1) Did any aircraft have a fully armoured cockpit inc glass / perspex in WW2?
2) Was any armoured glass proven to be cannon shell proof? If so, at what range?
3) Is there any evidence to prove which armoured glass construction system was the most protective while keeping optical clarity?

Thanks for your help chaps
Cheers
John

 

[Shortround6]

armoured glass was fairly heavy and trying to make entire canopy of it would run to hundreds of pounds. A few German Ground attack prototypes may have had fully armored cockpits but the 'canopy' was usually steel with small bullet proof windows. So small that they were rejected for service use.

Cannon proof covers too wide an performance envelope. 20mm cannon covered a type of weapon that could vary at least two to one in kinetic energy. Type of shell affects penetration enormously. A thick enough panel would certainly detonate a HE round on the outside, the question is if the blast would blow the armor glass out or push enough out as secondary fragments to cause damage to the pilot. I highly doubt the armor glass panel would have much transparency left but then it wouldn't after a hit for a large caliber MG either.

 

[razor1uk]

I can't remember perfectly off hand or locate the book in my collection without going through it or the personal book collection to find a single particular picture within just yet; but I seem think there is a picture from the cockpit looking though fitted armoured glass forwards from either an Bf.109 or 110 of some F or E model respectively.
It showed the glass screen that had suffered a single 20mm impact upon it in b/w, with the impact being off center, towards the approx;
X-axis 55% to 63% rightwards Y-axis 60% to 75% upwards, complete with locallised radial shatering, crazing shell fragments or/ impact fused glass
Iit was a small picture if I recall what it was like when I last saw it but as to where that/those books which had that photo they used was called, or from whom they got it from, I am at a loss.
It could have been in Me 109 by Uwe Fest? and or Messerschmit Hurricane by Chaz Boyey? (; or similar title Bowyer/Boywer? with other (co-)author?)

 

[davebender]

For comparison purposes...

How well armored are canopies on modern fighter aircraft such as the EuroFighter and F-15? I assume the pilot seat is armored and there is probably some lightweight armor such as Kevlar around the cockpit.

 

[razor1uk]

I think that somehow Kevlar doesn't has much to do with glass/transparant armour...

 

[stona]

I think that somehow Kevlar doesn't has much to do with glass/transparant armour...

I took it he meant in place of the steel plate you would find protecting the pilot in a WWII era aeroplane.
I don't think any such aeroplane had a completely armoured cockpit but some of the late Fw190 variants (I'm not trying to start a debate about which sub-type had which armour) were very heavily armoured,including additional,external,plate to protect the pilot and additional armoured glass to the side panels of the windscreen which,incidentally,proved unpopular.
Cheers
Steve

Cheers
Steve

 

[Readie]

I have sat in a Spitfire ( albeit a mock up) and looked through the armoured front screen and wondered how the hell anyone saw anything !!

I take the point made about weight, I guess that's why the bombers just relied on perspex.

Thanks SR6 for the cannon shell information. I hadn't thought about the splinter issue in the cockpit.

Does anyone know if the method of construction of armoured glass varied from manufactures ? Did any prove better optically protectively in service?

Thanks

John

 

[stona]

I have sat in a Spitfire ( albeit a mock up) and looked through the armoured front screen and wondered how the hell anyone saw anything !!
I take the point made about weight, I guess that's why the bombers just relied on perspex.
John

Here's the armoured glass from a Bf109. You can imagine just what that weighs and it's not very big.

Steve

 

[Readie]

Here's the armoured glass from a Bf109. You can imagine just what that weighs and it's not very big.

Steve

Yes, heavy, Its seems optically clear though.
Cheers
John

 

[Ratsel]

thats a 4" thick glass, same as the Galland panzer. The front windshield armor was mostly used in N.Africa. Designed to fragment even armor piercing rounds. Niether were bullet proof though.

 

[Readie]

thats a 4" thick glass, same as the Galland panzer. The front windshield armor was mostly used in N.Africa. Designed to fragment even armor piercing rounds. Niether were bullet proof though.

Thanks, were any LW ( fighters or bombers) aircraft front windscreens designed to be bulletproof?
If they were, do you know if they proved to be so in active service?

I'm not sure, at the moment, whether the term 'bulletproof' is accurate ( ie guaranteed) or if it is just protective in certain circumstances.

Cheers
John

 

[Coors9]

No way that one is 4 inches, maybe 2 or 2 1/4 .

 

[Ratsel]

Thanks, were any LW ( fighters or bombers) aircraft front windscreens designed to be bulletproof?
If they were, do you know if they proved to be so in active service?

I'm not sure, at the moment, whether the term 'bulletproof' is accurate ( ie guaranteed) or if it is just protective in certain circumstances.

Cheers
John

none that I know of from the Luftwaffe. Mabey the RAF or USAAF/USN had something. If they did I'm not aware of it.

Coors, I'm pretty sure its 4" thick. I could be wrong though.

*Edit I was wrong, that actual thickness is 10cm or 3.937" inches. The Galland panzer (rear protection) was 8cm or 3.15 inches.

 

[Matt308]

Looks about 4in to me. And pretty frickin' heavy I would imagine.

 

[Mustang nut]

Concerning armoured glass I have read in a few places fitting armoured glass reduced the speed of the airplane by a few MPH, which doesnt seem logical to me. Does it reduce speed and if so why. Or is it the generalk fitting of armour radios and other ancilliaries that produce this reduction.

 

[Coors9]

Read it's 90 mm thick. 3 1/2 inches. And 75mm/ 2.953 inches.

 

[tyrodtom]

If you look at the armored windscreen as applied to the later model Me-109's you'll notice it's a very unaerodynamic add on.

 

[Airframes]

To answer the question about speed reduction - weight penalty was negligible, but mounting internally, or as a 'bolt on' externally, could, and did, effect drag.
As to 'bullet proof' - in the true sense of the word, no. As to affording some protection - to an extent. It might stop the full force of a projectile, but would still 'scab off', depending on the round, angle of attack etc., which might injure the pilot/crew, but hopefully not totally incapacitate or kill. It has been known of course.
Regarding optically 'clear' - again it would depend on the production conditions and quality control (if any, depending on who, where, when etc.), as light diffusion, angle of light, UV conditions etc., could affect 'optically perfect' vision. Example, German manufactured 'panzerglas' had a green tinge, accentuated by the above conditions. Have a look at the edge of a normal, used in housing, sheet of float glass, and some idea of this will be noticed.
Post war, such companies (in the UK at least) as Pilkingtons, improved laminations, clarity etc, by additions such as Gold, and, if required, anti-flare coatings (as in camera lenses), but at much greater cost, and longer production times.
An example of cost; in the early 1960s, the Vickers Vanguard (turboprop) airliner had, for example, a small cockpit window, about the size of the average 'quarter light' in most cars of the period (the smallest window, each side, on the flight deck), each of which cost approximately £900 to produce. Although not rated as 'bullet proof', these were (probably) equal to, or better than, the average WW2 armoured screen.

 

[Ratsel]

Read it's 90 mm thick. 3 1/2 inches. And 75mm/ 2.953 inches.

If you have access to "Der Reichsminister der Luftahrt und Oberbefehlshaber der Luftwaffe: Technisches Amt GL/C Nr. 280 099/44 (E 2 VIII)" its a good read.

 

[razor1uk]

When mounted either externally or internally on Bf's 109's 110's IIRC, this addittional armoured screen was mounted infront of or behind the normal areo windscreen glazing/perspex/material; adding an addition layer of material with a slight anti-incedary air gap of say 5mm or more giving a small spaced-armour-effect.