How thick was the Skin FW-190 and Bf-109 on the wings and fusalage?

[the_emperor]

A quick question to draw ofthe knowledge of the forum:

How thick was the skin of the FW-190 and Bf-109 on the wings and fusalage, and what was it made of?

 

Cheers and many thanks

[zan64]

im an airplane mechanic and believe it or not when it comes to airplanes really have not changed much since this time far as construction materials and mechanical systems, such as hydraulics, are concerned (ok yeah we have composites and artificial fabrics but thats all like 21st century stuff, but the airframe guts and definitely skin of a b-17 and and an 80s era 747 are pretty similar). just going for a guess aluminum  2024 (copper alloyed aluminum) and guessing around 0.020-.025 thickness. the bf-108 i think has some magnesium parts in leading edge so the 109 might have that as well

 

and after google i found this, which is just what you are looking for 

https://apps.dtic.mil/sti/pdfs/ADA954228.pdf

 

edit: forgot a zero

Edited February 9, 2022 by zan64

[=420=Syphen]

26 minutes ago, zan64 said:

im an airplane mechanic and believe it or not when it comes to airplanes really have not changed much since this time far as construction materials and mechanical systems, such as hydraulics, are concerned (ok yeah we have composites and artificial fabrics but thats all like 21st century stuff, but the airframe guts and definitely skin of a b-17 and and an 80s era 747 are pretty similar). just going for a guess aluminum  2024 (copper alloyed aluminum) and guessing around 0.20-.025 thickness. the bf-108 i think has some magnesium parts in leading edge so the 109 might have that as well

 

and after google i found this, which is just what you are looking for 

https://apps.dtic.mil/sti/pdfs/ADA954228.pdf

 

 

 

It amazes me how so much of the vintage tech and techniques is used. I work part time in an aircraft shop that restores Aeronca / Bellanca mostly. I love doing fabric work. Something cathartic about the whole process. I recovered my own wings too. 

 

Edited February 8, 2022 by =420=Syphen

[the_emperor]

@zan64 thank you very much for that document.

As I am currently looking at a terminal ballistic test, which is unfortunately done on mild steel (WD 1010 hot rolled annealed and pickled) what thickness of that steel would come close to the aircraft skin in terms of resistance to explosive force and passing of the bullet (1/8 inch, 1/4 inch or 1/16inch)?

Thanks for the answers, as I dont heavy any knowledge in that regards ?

Cheers

Edited February 8, 2022 by the_emperor

[AEthelraedUnraed]

1 hour ago, zan64 said:

around 0.20-.025 thickness.

Is that inches or centimetres?

 

Regardless, that's pretty thin.

[Bremspropeller]

54 minutes ago, AEthelraedUnraed said:

Is that inches or centimetres?

 

Regardless, that's pretty thin.

 

Should be inches. It is thin, but it's still very robust.

Next time you're taking a trip on an airliner, watch how thin the skin actually is. And that's the doorframe, which actually is beefed up compared to the rest of the pressure-vessel. The wing-skin of the torque-box is a bit thicker, though.

 

I once had the chance of picking up an old truss of a Zeppelin which was made out of Elektron (the aluminium-magnesium alloy).

That stuff weighs almost nothing, yet still has a very high strength. It would be very ugly when set ablaze, though - hence the use in incendiary bombs.

[PatrickAWlson]

32 minutes ago, =420=Syphen said:

 

It amazes me how so much of the vintage tech and techniques is used. I work part time in an aircraft shop that restores Aeronca / Bellanca mostly. I love doing fabric work. Something cathartic about the whole process. I recovered my own wings too. 

 

 

As a lover of early flight: by 1918 the following systems had been developed:

All currently known flight surfaces

All metal monoplanes

Pressurized cabins

High altitude engines

 

The advances from 1903 to1918 are, to me, just amazing.

 

[Gambit21]

There's a section of a British Lancaster bomber in a museum up this way...forward half with cockpit.

You can climb inside etc.

 

It's shocking how thin the skin is, and hard to imagine that even a .22 cal would notice it unless hitting at an extremely shallow angle.

 

 

 

 

 

[Jaws2002]

This article about the FW-190 construction should give you a good idea.

 

http://legendsintheirowntime.com/LiTOT/FW190/FW190_Av_4410_DA.html

 

the Rear fuselage is slightly lighter than 24ST, but the front is pretty heavy, with large, strong, double sided, access panels.

 

 

Edited February 8, 2022 by Jaws2002

[Aurora_Stealth]

Yep, and it should be noted that the reason why especially the fuselage thickness could be so thin with only minor reinforcement and fewer structural spars etc on the inside is because most of the fuselage strength is coming from the shape of the joined skins (aka monocoque / structural skin)... one final thing that helps with the '109 is it uses interlocking fuselage skin joints for its fuselage sections... to avoid the need to be heavily reinforced.

 

This meant you only need to reinforce key places like the wing spar, fuselage to gear joint (which were joined together for simplicity and weight saving) and the tail to fuselage joint - leaving more space in the fuselage for embedding equipment. This removed a great deal of potential weight that you'd have from a more conventional / interweaved structure.

Edited February 8, 2022 by Aurora_Stealth

[CUJO_1970]

Need moar thick plz

 

[Jaws2002]

This document shows the skin on the Me210 was .05 in.

 

https://books.google.ca/books?id=REZQAAAAYAAJ&pg=RA12-PA53&lpg=RA12-PA53&dq=fw+190+skin+thickness&source=bl&ots=sN9C351xAM&sig=ACfU3U2G7VDAJbZLL9M89f8Ue36pw7d9TQ&hl=en&sa=X&ved=2ahUKEwi95NG7vPD1AhWIFzQIHcO7Cp8Q6AF6BAgTEAM#v=onepage&q=fw 190 skin thickness&f=false

[[CPT]Crunch]

Typical military trash hauler has zones where they spread the structural members out a bit wide and keep obstructing parts and lines free that are marked and labeled for cutting to escape.  The aircraft equipment provided cutting axes aren't very sharpened so they can't be used as hi-jack weapons and the handles aren't very long but they work like a can opener, you could also cut through with your average good quality hunting or combat knife if your motivated enough.  

 

Used to occasionally see the crash axes stowed in the upper baggage compartments on commercials in days long gone by, but not so much lately this century. 

[AndyJWest]

Putting a compound curve into a skin for a Seversky P-35:

 

As has been said above, it is the shape that gives the skin strength.

 

[the_emperor]

Thank you all,

the reason why I am asking is, that I found some test regarding the 20mm Hispano / AN-M2/3 ammunition.

unfortunately  they did not test it on FW or BF fuselages ?

that can all be found here, if someone is interested:

 

Edited February 8, 2022 by the_emperor

[Jaegermeister]

1 hour ago, Jaws2002 said:

This document shows the skin on the Me210 was .05 in.

That's about 4 or 5 times thicker than a soda can 

[Irishratticus72]

8 minutes ago, Jaegermeister said:

That's about 4 or 5 times thicker than a soda can 

You mean beer can, right? I can't get used to these new fangled measurement systems. 

[Cravis]

I do structure modifications and repairs on aircrafts. That said I work on "modern" aircraft not on warbirds.

Usual skins thickness varies but common gauges are 0,063" (1,6mm), 0,05" (1,2mm), 0,04" (1,0mm), 0,032" (0,8mm) and 0,025" (0,6mm). Sheet metal is usually 2024 with a T3 temper. We also work with T0 but only to later temper it to something else like T42.

Aircraft usually use ALCLAD: Meaning the core is 2024 and a thin layer high-purity aluminium (~99,99%) is plated on the outside for corrosion protection.

Aircrafts usually do not have a uniform skin thickness. The skin is either chemically milled or has a waffle doubler attached (usually bonded). The skin therefore is thicker  beneath stringers and frames and thinner within the "pockets".

 

As for armour protection: There is none.

 

The only effect a aircraft skin could have is to induce tumble into a projectile therefore reducing the penetration power for anything it hits after the skin.

 

I once repaired a bullet hole in the ceiling of an aircraft. Apparently a passenger of this plane played with his gun on the lavatory and accidentally fired it... don't ask me what was going on there I really have no idea... anyway it was a rather clean round hole with a bit of fraying. I drilled it up to about 1/2" to remove the damage to the skin and installed a doubler.

Edited February 8, 2022 by Cravis

[Aurora_Stealth]

2 hours ago, Cravis said:

I once repaired a bullet hole in the ceiling of an aircraft. Apparently a passenger of this plane played with his gun on the lavatory and accidentally fired it... don't ask me what was going on there I really have no idea... anyway it was a rather clean round hole with a bit of fraying. I drilled it up to about 1/2" to remove the damage to the skin and installed a doubler.

 

That's a funny tale.

 

Probably best not to know how the gun got onboard. Surely this has got to be in the US right? hopefully not recently haha

 

I just have this thought of some guy in the lavatory making strange noises, people knocking on the door as the fasten seatbelt sign comes on... like some kind of strange scene off the film Airplane... shoots gun accidentally when a bit of turbulence hits... looks up... the dust goes in his eye and then shoots himself in the foot while zipping up to complete the irony.

[Feathered_IV]

4 hours ago, Jaws2002 said:

This document shows the skin on the Me210 was .05 in.

I measured the fuselage skin of a P-51 and wing of a T-6 a while back and they were about the same as that.  

[Yogiflight]

Aluminum can be quite tough. But I think it not the aluminum, used back then

 

 

[Cravis]

1 hour ago, Aurora_Stealth said:

Probably best not to know how the gun got onboard.

 

Well sorry to disappoint you but it wasn't something crazy as this. The aircraft in question was a KingAir 200 from Egypt. As far as I know the gun was brought on board legally by some military officer.

It also didn't happen during flight but on the ramp.

 

The "lavatory" on that KingAir is the seat right across the entrance door. There is a toilet beneath the seat when you flip up the seat cushion and curtain on the bulkhead to separate the cabin.

[Aurora_Stealth]

31 minutes ago, Cravis said:

 

Well sorry to disappoint you but it wasn't something crazy as this. The aircraft in question was a KingAir 200 from Egypt. As far as I know the gun was brought on board legally by some military officer.

It also didn't happen during flight but on the ramp.

 

The "lavatory" on that KingAir is the seat right across the entrance door. There is a toilet beneath the seat when you flip up the seat cushion and curtain on the bulkhead to separate the cabin.

 

Aaa fair enough, I suspected it'd have to be some kind of privately operated, military or misc aircraft for that sort of thing to occur. I was just being ridiculous don't worry.

 

Heh I guess you gotta hope they have good toilet manners as that'd be a pretty disturbing flight otherwise if you're sitting nearby - on the other hand I guess as its a prop you'll probably not hear much with the background noise anyway.

Edited February 8, 2022 by Aurora_Stealth

[zan64]

10 hours ago, AEthelraedUnraed said:

Is that inches or centimetres?

 

Regardless, that's pretty thin.

0.020-0.025 inches, when its all wrapped around the airframe (the skeleton) its very strong, like g-force will bend the airframe before damaging the skin

2 hours ago, Yogiflight said:

Aluminum can be quite tough. But I think it not the aluminum, used back then

 

 

aluminum! but it is not your typical soda can, is alloyed so a bit tougher but nonetheless would never stop a bullet. 

11 hours ago, the_emperor said:

@zan64 thank you very much for that document.

As I am currently looking at a terminal ballistic test, which is unfortunately done on mild steel (WD 1010 hot rolled annealed and pickled) what thickness of that steel would come close to the aircraft skin in terms of resistance to explosive force and passing of the bullet (1/8 inch, 1/4 inch or 1/16inch)?

Thanks for the answers, as I dont heavy any knowledge in that regards ?

Cheers

no problem, an interesting thread! youd have to ask the other mechanic in this thread as he knows more, im an engine type of guy, but i never heard of steel skin, the airplane would be too heavy edit: sorry misunderstood - cant answer your question, have to ask an engineer or in particular a metallurgist!

Edited February 9, 2022 by zan64

[Aurora_Stealth]

19 hours ago, the_emperor said:

@zan64 thank you very much for that document.

As I am currently looking at a terminal ballistic test, which is unfortunately done on mild steel (WD 1010 hot rolled annealed and pickled) what thickness of that steel would come close to the aircraft skin in terms of resistance to explosive force and passing of the bullet (1/8 inch, 1/4 inch or 1/16inch)?

Thanks for the answers, as I dont heavy any knowledge in that regards ?

Cheers

 

I'd recommend finding a test comparing original material or close if you can (there are some out there), at least some kind of aluminium as these materials have different density, stiffness and elasticity which will affect ballistics especially at range or with any kind of angle involved. It's not just its shear (linear) strength that matters.

 

Just to reiterate the shape of the part being shot at (e.g. C or D-shaped section as opposed to a plate etc) will matter when absorbing the energy from gunfire. So for example shooting at a simple flat plate at a side angle will not give a comparable result to what happens firing at an aircraft that has shaped / stressed skins / monocoque structures.

 

The use of certain alloys also plays a factor but I'm not going into all that.

 

To be brief, quick and dirty though (please don't take this as gospel) ... simplistically between mild steel and an aluminium alloy you're looking at roughly half to a third thickness for steel depending on the property you measure (there are too many different properties to directly align). So whatever is closest to 40% thickness would probably be a rough compromise. Again, I really wouldn't rely too much on any results calculated from this as its a very crude and simplistic way of comparing.

Edited February 9, 2022 by Aurora_Stealth

[the_emperor]

@Aurora_Stealth

unfortunately I yet have not found any detailed test against aluminium in regards to hole size created. At least the tests give a time for the shell rupture after impact (40-45 microseconds).

Many thanks

Edited February 9, 2022 by the_emperor

[JV69badatflyski]

22 hours ago, CUJO_1970 said:

Need moar thick plz

 

Those 0.50 made some serious holes ...

sarc

[messsucher]

26 minutes ago, JV69badatflyski said:

Those 0.50 made some serious holes ...

sarc

 

What those, like many? The plane was hit by ONE .50 cal bullet :DDD

[Jaws2002]

6 hours ago, Aurora_Stealth said:

I'd recommend finding a test comparing original material or close if you can (there are some out there), at least some kind of aluminium as these materials have different density, stiffness and elasticity which will affect ballistics especially at range or with any kind of angle involved. It's not just its shear (linear) strength that matters.

 

Just to reiterate the shape of the part being shot at (e.g. C or D-shaped section as opposed to a plate etc) will matter when absorbing the energy from gunfire. So for example shooting at a simple flat plate at a side angle will not give a comparable result to what happens firing at an aircraft that has shaped / stressed skins / monocoque structures.

This is important. Terminal ballistics, specially when we talk about complex structures is very complicated. So many things can affect the results. Metal thickness, structure around it. If we talk about explosive shells , the volume of air inside the cavity is really important and it matters a lot if it's an open cavity, or a closed space. 

[Asgar]

Not sure about the exact composition but both the 109 and 190 used Duraluminium as far as I'm aware, which is the same aluminium alloy used for the Corsairs armor plates

  

On 2/8/2022 at 1:49 PM, zan64 said:

im an airplane mechanic and believe it or not when it comes to airplanes really have not changed much since this time far as construction materials and mechanical systems, such as hydraulics, are concerned (ok yeah we have composites and artificial fabrics but thats all like 21st century stuff, but the airframe guts and definitely skin of a b-17 and and an 80s era 747 are pretty similar). just going for a guess aluminum  2024 (copper alloyed aluminum) and guessing around 0.020-.025 thickness. the bf-108 i think has some magnesium parts in leading edge so the 109 might have that as well

 

and after google i found this, which is just what you are looking for 

https://apps.dtic.mil/sti/pdfs/ADA954228.pdf

 

edit: forgot a zero

as for aluminium 2024, or WL 3.1364 for my European friends  (I really prefer the WL numbers, you know right away what you're dealing with) 
it's elasticity limit is around 315 N/mm², tensile strengh is at around 440 N/mm² and it's failure strain is around 12%

while Dural or Duraluminium has a tensile strength of up to 500 N/mm² and a failure strain is up to 22%, didn't find a number for elasticity limit though (for comparison, S355 steel has a tensile strength of 510 N/mm² and failure strain of 19%)

Edited February 9, 2022 by Asgar

[the_emperor]

@Asgar

Thank you very much ?

[Kurfurst]

Well it wasn't much, despite being the thicker ones, due to box spar construction (skin was a load bearing element). 109E inspection by the French. F may have been thinner, G may have been thicker.

 

[the_emperor]

5 hours ago, Jaws2002 said:

Terminal ballistics, specially when we talk about complex structures is very complicated. So many things can affect the results. Metal thickness, structure around it. If we talk about explosive shells , the volume of air inside the cavity is really important and it matters a lot if it's an open cavity, or a closed space.

Absolutely, its is very complex, but unfortunately sometimes you have to use what you can find. Especially in this case for the 20x110mm M97 round with the No.253 and M75 fuze which in this case where shot at simple metal plates (for good x-ray documentation)

thanks all for the input  

[zan64]

On 2/10/2022 at 12:27 AM, Asgar said:

as for aluminium 2024,

ah but like what the other mechanic said, its technically 2024 T3, does it make a difference?

[Viktor59]

https://www.teknika4.com/es/aluminio-aeronautico

[[F.Circus]MoerasGrizzly]

On 2/8/2022 at 5:14 PM, PatrickAWlson said:

 

As a lover of early flight: by 1918 the following systems had been developed:

All currently known flight surfaces

All metal monoplanes

Pressurized cabins

High altitude engines

 

The advances from 1903 to1918 are, to me, just amazing.

 

Don't forget the gyroscopic autopilot!

[Avimimus]

On 2/8/2022 at 9:03 AM, the_emperor said:

@zan64 thank you very much for that document.

As I am currently looking at a terminal ballistic test, which is unfortunately done on mild steel (WD 1010 hot rolled annealed and pickled) what thickness of that steel would come close to the aircraft skin in terms of resistance to explosive force and passing of the bullet (1/8 inch, 1/4 inch or 1/16inch)?

Thanks for the answers, as I dont heavy any knowledge in that regards ?

Cheers

 

I'd love to see someone build a simulated wing box and then fire 0.303 at 100 yards into it... I bet one could crowd fund for materials.

 

The main thing I wonder about is how bullets would behave within the wing/airframe...

How much dispersion is added by the yaw induced through passing through the wing?

How much dispersion is added by the first ricochet?

Is there enough energy to damage components/pipes/wires left after the first 0.303 ricochet?

[ACG_Cass]

The RAF did it. I saw the report in the national archives last month.

 

 

I unfortunately didn't photograph the whole report.

[354thFG_Rails]

11 hours ago, zan64 said:

ah but like what the other mechanic said, its technically 2024 T3, does it make a difference?

Short answer… no. 
 

all that’s really getting at is you could get away with thinner material using duralumin and still retain relatively the same strength. A bullet is still going to penetrate the thin skin regardless. 

Edited February 11, 2022 by QB.Rails

[357th_KW]

Great stuff there @ACG_Cass!  Worth noting is the velocities of the two .50 caliber rounds being used there.  Neither is M2 AP, being down 60 fps and 200 fps.