Armored Glass as rearward armor in Cockpits

[CountBreznak]

I was thinking about armor in airplanes when i saw the current dev diary. It occured to me, that to my knowledge the russians where the only ones that came up with the use of armored glass as rearward cockpit armor (e.g. Yak 1b or La 5FN).

My question is, were they really the only ones? It surely increases visibility a lot, but is it effective protection? How thick was the armored glass? Or does the use of steel just offer a better protection for the pilot?

[Stig]

There is also the armoured glass headrest that we have in the Bf 109g2.

[=TBAS=Sshadow14]

its mostly for Placebo effect.

Sure some armoured glass might stop 7mm MG and 13mm MG
But very few armoured glass you can still see through would stop
20mm, 23mm, 30mm and so on..
Not even most armoured steel in planes would hold upto that.

Thats why i say Armour packs on 110 useless when ground attacking.
No armour going to stop a 45mm or 85mm Russian Anti A shell.

[Finkeren]

its mostly for Placebo effect.

 

Sure some armoured glass might stop 7mm MG and 13mm MG

But very few armoured glass you can still see through would stop

20mm, 23mm, 30mm and so on..

Not even most armoured steel in planes would hold upto that.

 

Thats why i say Armour packs on 110 useless when ground attacking.

No armour going to stop a 45mm or 85mm Russian Anti A shell.

 

No amount of armor that can be carried on a WW2 fighter will save you from a 20mm AP or any kind of 30mm shell or larger, but that doesn't mean the armor is useless.

 

The standard fighter armament for most of the period this sim covers was either 1-2 20mm cannon and a couple of LMGs or a combination of LMGs and/or HMGs, so the pilot armor would actually offer at least some protection against the vast majority of projectiles hurled against you, because regardless of the armament configuration, machine gun bullets always outnumber cannon shells. 

 

Let's take a typical example: The Yak-1 s.69. It has 120 rounds of 20mm ammo for the ShVAK, of which only half are AP that can actually defeat the headrest armor, and 1500 rounds of 7.62mm for the ShKAS. Every single one of those 1620 rounds has the potential to kill you instantly, but only 60 of them can be counted on to penetrate the pilot armor, or to put it another way: Your armored headrest can potentially stop 96.3% of the projectiles coming your way. 

Edited December 16, 2017 by Finkeren

[Holtzauge]

Also don't forget that FMJ and AP start tumbling if they hit something prior to making contact with the armour plate and the penetration capability is significantly reduced if this happens. For example, a lot of fighters had radio and other equipment located behind the pilot in the fuselage and things like that will cause a bullet or cannon shell to start tumbling and in that case the back or head armour would have a good chance of stopping even AP.

[NZTyphoon]

Also don't forget that FMJ and AP start tumbling if they hit something prior to making contact with the armour plate and the penetration capability is significantly reduced if this happens. For example, a lot of fighters had radio and other equipment located behind the pilot in the fuselage and things like that will cause a bullet or cannon shell to start tumbling and in that case the back or head armour would have a good chance of stopping even AP.

Plus, while it's true that a direct strike from a large calibre round would defeat all but heavy-duty armour, it doesn't mean that adding such protection is useless, because armour and bullet-resistant glass can stop shrapnel from the likes of (say) a 20 or 30 HE or AP round that has struck the airframe, or equipment within the airframe: it can also stop shrapnel from an exploding AA shell from damaging important components of the airframe, including the pilot and aircrew.

 

Just for interest, from a company manufacturing modern automotive armoured glass here is a table of the thickness of armoured glass required to sustain direct hits from modern pistols and assault weapons

 

Armored glass that is 21mm thick is ranked B4, which is able to stop a handgun; 70mm glass, or B7 rank, is able to stop a high-powered rifle (see the ballistic chart below) (from here)

 

 

I'm not sure how thick the rear armour-glass pane on the Yak 1b was; I'm guessing around 70-80mm, or, roughly B7 grade.

Edited December 17, 2017 by NZTyphoon

[Holtzauge]

Yup, after passing through some minor obstacle the glass should even protect against AP and my guess on the data you posted is the Yak armoured glass would stop FMJ up to German 13 mm at least and maybe even US 50-cal if they passed through some fuselage skin causing them to start tumbling.

[Mitthrawnuruodo]

Glass is effective as armor, at least against rifle rounds. However, about three times the mass is required to achieve protection equivalent to steel.

 

As weight is the universal enemy of aviation, the use of glass for armour is very limited. Usually, only the part right in front of the pilot’s face is armoured.