Aircraft made in steel?

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Seems like in some places, or at least in Germany, such aircraft were considered.
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Perhaps someone can chime in wrt. this suggestion, and viability of steel aircraft in general?
Fleetwings built the BT-12 Sophomore stainless-steel trainer.
Acquired by Kaiser in 1943. Eaton records show 24 delivered.
Aviation magazine did one of their Design Analysis articles on the BT-12 in June, 1942.
Aviation magazines are available at the Internet Archive.
 
Fleetwings built the BT-12 Sophomore stainless-steel trainer.
Acquired by Kaiser in 1943. Eaton records show 24 delivered.
Aviation magazine did one of their Design Analysis articles on the BT-12 in June, 1942.
Aviation magazines are available at the Internet Archive.
Mea culpa. Didn't read my file browser carefully enough. The Design Analysis was in the October, 1943, issue of Aviation.
 
Much of the Hawker Hurricane's fuselage framework was made of steel, wasn't it?
Framework Yes. But this question asks which aircraft have been made predominantly from steel,"/ i.e skin too, preferably monocoque or semi-monocoque.
 
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Fleetwings Sea Bird was all stainless....
Stainless steel seems like a great material for seaplanes but I wonder how the spotwelds held up against corrosion. Unfortunately, the Fleetwings fleet size isn't big enough to give us much service data.
 
I've been watching the restoration of the Il-2 in NASM's shop, and a lot of the forward fuselage is still, mostly as armor plate protection.

Perhaps someone can chime in wrt. this suggestion, and viability of steel aircraft in general?
You can, as many post show, make planes out of steel.
Wither they should is another question.

There were a number of reasons to try.
Mostly related to material shortages. The Fleetwing was from 1934-35 and even all metal aluminum planes were not common or only a few years old.
Corrosion coatings/treatments were in their infancy so Stainless steel may have been seen as alternative in regards to maintenance.
Steel companies were also pushing stainless steel for all sorts of products.
ss-Ford-1.jpg

I got a short ride in one of these back around 1970. A friend's father (Ex- Corsair pilot) was an executive in a local steel company got access to it and a newer one for for a local celebration parade.

For aircraft the question was also if steel made the plane lighter or heavier and if heavier, what did it do for the designer that made up for the weight.
The IL-2 offered protection. It also cost payload (bombs, guns, fuel) or performance.
IL-2 had over 70% more power than Fairey Battle, wasn't much faster, flew 1/2 as far. only carried about 30% more bombs. A lot of trade-offs.
Using the steel armor was an attempt to save weight as the armor doubled as structural weight, instead of adding armor to an existing structure.
 
You can, as many post show, make planes out of steel.
Wither they should is another question.

There were a number of reasons to try.
Mostly related to material shortages. The Fleetwing was from 1934-35 and even all metal aluminum planes were not common or only a few years old.
Corrosion coatings/treatments were in their infancy so Stainless steel may have been seen as alternative in regards to maintenance.
Steel companies were also pushing stainless steel for all sorts of products.
View attachment 758497
I got a short ride in one of these back around 1970. A friend's father (Ex- Corsair pilot) was an executive in a local steel company got access to it and a newer one for for a local celebration parade.

For aircraft the question was also if steel made the plane lighter or heavier and if heavier, what did it do for the designer that made up for the weight.
The IL-2 offered protection. It also cost payload (bombs, guns, fuel) or performance.
IL-2 had over 70% more power than Fairey Battle, wasn't much faster, flew 1/2 as far. only carried about 30% more bombs. A lot of trade-offs.
Using the steel armor was an attempt to save weight as the armor doubled as structural weight, instead of adding armor to an existing structure.
That car is bitchin'!
 
WW2 aircraft were generally not made from Aluminium but from Duralumin an alloy developed in Germany from 1909, it is an alloy of mainly Aluminium Copper Magnesium and Manganese. From an article/study posted here the alloys used by the USA and Germany were almost identical, British differed slightly
I doubt there is any use of pure aluminium in anything other than a heat sink. The currently machinable 6061-T6 contains silicone and magnesium. The 5052-H32 used for sheet metal, contains magnesium. The aircraft structural grades are 2024-T4 and 7075-T6, and they contain copper, and zinc respectively. Duralumin is very similar to the 2000 grade alloys. They all primarily are aluminium. All densities are around 2700kg/m^3 (0.1lb/in^3) and all have elastic modulii of around 70GPA (10Mpsi). The alloys affect corrosion resistance, work hardenability and heat treatability, and ultimately, the strength.
 
Nope. Steel can contain 50% alloying additives, i.e. elements other than iron. Please use correct analogies.

PS. I could tell you a lot about aluminum alloys and their characterization (including elemental analysis). You may not believe me, but sometimes an opponent can have a pretty decent background in materials science. ;)
Please name a steel alloy that is 50% stuff other than iron.

Stainless steels contain quite a bit of nickel and chrome. Invar and Kovar contain more alloy, but are still primarily iron. If you mix iron with 6.67% carbon by weight, you have a mineral called cementite, Fe3C. It is no longer a metal. All the other steel alloys contain trace elements that affect heat treatment, corrosion and machinability.
 
Stainless steel MiG-25s aside, steel is heavier than aluminium.


Also, steel is an alloy needing further working, while AIUI aluminum is mined and faster to get onto aircraft. Here in Canada, aluminum is readily available.
This is slightly complicated. Steel has three times the elastic modulus of aluminium and three times the density. If we build a truss structure in which the pieces all are loaded in tension and compression, there is no structural difference between steel and aluminium. Cost and ease of fabrication will be very important. If you make a cantilevered structure with some weight limit, the conforming aluminium structural section will bigger, stiffer and stronger.

Structures usually fail in compression by buckling, so a fatter aluminium section may have an advantage in certain truss structural elements.

I am grossly simplifying things here.

We should distinguish between entirely steel structures such as the J2 I noted above, and composite structures containing steel. Steel is an excellent material for making tubular trusses on many aircraft including Hurricanes, but ultimately, they are covered in fabric. The Hurricane's rounded fuselage shape was due to wooden formers and stringers.

On the Hawker Typhoon and Tempest, the forward fuselage was steel tube covered by removeable aluminium panels. The rear part was aluminium monocoque.
 
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This is slightly complicated. Steel has three times the elastic modulus of aluminium and three times the density. If we build a truss structure in which the pieces all are loaded in tension and compression, there is no structural difference between steel and aluminium. Cost and ease of fabrication will be very important. If you make a cantilevered structure with some weight limit, the conforming aluminium structural section will bigger, stiffer and stronger.

Structures usually fail in compression by buckling, so a fatter aluminium section may have an advantage in certain truss structural elements.

I am grossly simplifying things here.

We should distinguish between entirely steel structures such as the J2 I noted above, and composite structures containing steel. Steel is an excellent material for making tubular trusses on many aircraft including Hurricanes, but ultimately, they are covered in fabric. The Hurricane's rounded fuselage shape was due to wooden formers and stringers.

On the Hawker Typhoon and Tempest, the forward fuselage was steel tube covered by removeable aluminium panels. The rear part was aluminium monocoque.
Hi
For the 1937 view on this subject we have 'Metal Aircraft Construction' by M Langley, on use of duralumin sheet for monocoque fuselages instead of steel it states the following (under 'The Material of the Monocoque'):
Image_20240120_0008.jpg

Some examples of 'steel' framework:
Image_20240120_0007.jpg

A list of steels and alloy steels in use for aircraft construction in 1937:
Image_20240120_0001.jpg

Image_20240120_0002.jpg
Mike
 
re
Please name a steel alloy that is 50% stuff other than iron.

:) Just one example, 330 stainless steel can be as high as 53%+ major alloying elements:

Nickel34.00-37%
Chromium18.00-22.00%
Carbon0.08% Max
Silicon1.00 – 1.50%
Manganese2.00 Max%
Phosphorus0.03 Max%
Sulfur0.03 Max%
Copper1.00 Max%
IronBalance

310 & 314 stainless steels are well in the 40%+ major alloying element range.

There also used to be some very high alloy armour steels for special purposes, but they were very expensive to manufacture. I did a quick search and did not find them listed as such, so maybe they are not in use anymore.

:)Disclaimer
For us AR types, the definition of steel, stainless steel, steel alloy, Nickel alloy, etc is a bit imprecise in some ways.

Wiki for example defines steel as being a mix of iron and carbon (1.7% max) and alloy steel has from 1% to 50% alloying elements. While iron combined with more than 1.7% carbon is cast iron.

If you look around you may find steel defined by chemists and metallurgists as iron and upto 2% carbon, and alloy steel as whatever the alloy composition is.

NiChrom alloys have a large % of Nickel and Chrome as their major alloys. If NiChrome is alloyed with Iron but NOT carbon then it is usually still called a NiChrome alloy, as opposed to a steel alloy like 330 stainless steel. However, if you arbitrarily define alloy steel as having between 1% and 50% alloying elements (not counting carbon) then you are saying 330 stainless steel is not a steel alloy - even though the definition of steel is iron mixed with less than 1.7% (or less than 2% carbon). And so on . . .

Some NiChrome Alloys
Alloy% Content
NiCrFe
NiCr 80/2080200
NiCr 70/3070300
NiCr 60/166016Balance
NiCr 35/203520Balance

As you can see from the tables above, 330 stainless steel has similar Nickel and Chrome % to the NiCr 35/20 alloy, with the balance being Iron - but no Carbon. Does adding the 0.08% Carbon really turn it into a alloy steel (or in this case stainless steel)?
 
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