Sten SMG aircraft: productionized aircraft part 1, the reality

[MikeMeech]

Hi
Air-Britain's three volume work on Miles Aircraft by Peter Amos contains detail on the M.20 in Volume 2, 'Miles Aircraft - The Wartime Years'. This is probably the most information available from the documents that still exist (unless someone has hoarded some documents somewhere). Extract from "Brief Specification":

Performance details:

Cut-away, shows inner wing fuel tanks, radio equipment in rear fuselage, armour plate behind seat etc:

There are also detailed drawings of the 8 gun armament fit and cockpit canopy.

Mike

 

[BarnOwlLover]

You know if that book has info on either of the Miles M23 projects? The original M23 was a small, mostly wood(?) interceptor fighter powered by a Merlin or Griffon, and the M23A was a high altitude interceptor powered by a Merlin 60 series engine. As far as I know, though, these were just design exercises.

 

[GregP]

Fair enough.



Simple - it probably was. Robust - according to whom?



It have had no guns installed.



RAF (as well as other air forces/services of the time) were looking for aircraft that can bring required firepower to the piece of the sky, within time required, in order to kill enemy aircraft. Unarmed aircraft don't qualify, no matter how they are easy to repair or easy to make.



No guns, no ammo. No flight test report, making the speed and RoC figures suspicious as the 400 mph XP-39, XF4U-1 and XP-38 turn of speed.
RAF/AM did the right thing when decided not to buy it.

That's a lot of argument for one airplane that didn't make production. But, decently done, Tomo. It likely explains the lack of production which seems to be as you wanted it and as it happened.

I still think some air support would have been better than no air support in places that historically didn't have any.

Your opinion, of course, may vary, and likely does. That's OK. Neither of us can change that in any case.

After this very simple airplane, I nominated the F6F and F4F, in no particular order. I really like the switch to raise the landing gear in the F6F, as opposed to the hand crank in the F4F/FM. It's more complicated than a hand crank, but not by much.

Cheers.

 

[Thumpalumpacus]

I'm still trying to figure out what a "Sten SMG" aircraft is. Arming an aircraft with one Sten doesn't seem, er, prudent.

 

[BarnOwlLover]

I know that I've mentioned the P-40 a couple of times, and even though it wasn't a great performer in the ETO (basically too slow for northern European operations, and not a good altitude performer even with the Merlin), it was cheap, simple (for a modern aircraft) and robust.

I've also mentioned the P-51, as it married advanced featured (mostly aero) into a relatively simple to produce and maintain airframe. Even the Lightweights (culminating on in the P-51H) took all of this a step further, and were optimized for both reduced weight and increased ease of maintenance for ground crews.

And the Mosquito, though made out of wood, did used an advanced form of sandwich construction that would be seen again until the 1960s (though plywood and balsa wood was replaced with things like aluminum sheet, aluminum or Kevlar honeycomb, and ultimately carbon fiber composite). Also, things like F1 cars, Indy Cars, and Le Mans Prototype-type sports cars use a similar chassis construction (though again with more modern materials). That said, it does seem that ultimately metal monocoque aircraft were easier to maintain and repair long term (though long term isn't necessarily a thought in wartime).

And of the Soviet fighters, they were, especially the Yakovlev and Lavochkin fighters were noted for being high performance while being insanely simple to built and maintain, even allowing for the fact that wood wasn't the best material to build planes out of in the Russian climate (which resulted in the all metal Yak-3 M-107 and La-9/11 post war).

Probably the ultimate example (that saw use) was the He-162. Which, of course, sort of worked. How prudent it was to build a jet like the 162 under normal circumstances is at best debatable. But Germany by them was in a serious SHTF time, and just about anything they could put in the air was better than nothing. Even if the 162 at times (like the Me-163) was just as dangerous to its own pilot as to the enemy.

 

[Shortround6]

I know that I've mentioned the P-40 a couple of times, and even though it wasn't a great performer in the ETO (basically too slow for northern European operations, and not a good altitude performer even with the Merlin), it was cheap, simple (for a modern aircraft) and robust

We may mean different things.

1, The P-40 wasn't actually slow. At altitudes where it's engine worked it was fast as a Spitfire V. So for installed horsepower it was actually pretty good.
2, The engine did crap out at much over 12-13,000ft with Allisons before the P-40M and those only picked up about 3-4,000ft.
3. The P-40F was good for around 360-365mph at 20,000ft in US figures and the A&AEE tested one at 354mph at 20,400ft. British figures are for a weight about 400lbs heavier than the US figures (?) which leads us to.
4. while fast it couldn't climb even if you strapped a rocket to it. The British were testing it at 8900lbs. or about 27% heavier than Spitfire MK V.
5. Cheap is certainly debatable, An almost 6500lb empty weight fighter, while cheap compared to a P-38 or P-47 is not a cheap airplane compared to a Spitfire or 109 or???
They also had a huge production operation going and some months they rolled over 400 P-40s out the door. There is a certain economy of scale.
6. Simple, compared to what? yes it was simple compared to a P-38 (2 engines). P-47/F6F/F4Us thousands of pounds heavier, 18 cylinder engines and two stage superchargers.
Now engines aside, what WW II fighters were more complicated? They all had similar instrument panels, most had similar radios, they all used similar controls (at least until the P-38 with the powered ailerons), we can argue about hydraulic landing gear retraction vs electric or even hand cranks but most planes had retracting mechanisms and flaps (no double slotted flaps) so most single engine fighters used pretty much the same number of systems.
7. Robust, OK but that was part of the weight and part because the P-36 was not as robust as desired. But they paid for it with several hundred pounds of extra weight.

And of the Soviet fighters, they were, especially the Yakovlev and Lavochkin fighters were noted for being high performance while being insanely simple to built and maintain, even allowing for the fact that wood wasn't the best material to build planes out of in the Russian climate (which resulted in the all metal Yak-3 M-107 and La-9/11 post war).

Insanely cheap looks a little looking at. Soviet wooden fighters were not built with slabs of wood dragged to the factory by wood cutters and horse drawn sleds.
They used laminated veneer plywood. See Wiki
"The I-301 airframe was partially made of "delta wood": a material composed of very thin (0.35–0.55 mm) layers of birch or pine wood veneer, and a phenol-formaldehyde resin known as VIAM-B-3, which together were baked at high temperatures and pressures. Delta wood was used for critical parts of the airframe. This novel construction material had tensile strength comparable to that of non-hardened aluminum alloys and only 30% lower than that of precipitation hardened D-1A grade duralumin. It was also incombustible and completely invulnerable to rot, with service life measured in decades in adverse conditions."

Now you need veneer lathes that will cut the selected logs to the required thickness and widths. You need a chemical industry that can provide the required resin glue in the required quantities ( dozens of gallons per plane ?) and you need the autoclaves to bake the sheets and structures at the temperature and pressures needed.
Once you have established the supporting supply network actual assembly may be easy but trying to figure out the cost of some the supply network is hard. Some of the supply network could be supplying several different airframe companies including rival design teams.
Also note that some of the claims did not prove out in practice under mass production. Some areas got too much resin and some got too little and if not baked at the proper temperature/pressure/time you don't get the results you want.
Also note that slopping on extra glue to poorly fitted parts does NOT make up for sloppy fit. It also makes some the parts a lot heavier than designed.
Hammering metal bolts though miss aligned wooded holes makes for insanely simple construction, you also have to have insanely simple pilots to fly such things (or be threatened with death).

If you don't have enough aluminum it is a solution, but people often confuse wood with cheap. A lot depends on the woods, the availably of the woods and the availability of the glues/adhesives and other things.

I would also suggest that NO country and the number of piano or fine cabinet makers needed to turn out hundreds of wooden aircraft a month.


The construction was also bulky. the wing spars actually took up a fair amount of room inside the wing and when they started using metal spars they could fit in larger fuel tanks and the all metal wings allowed for even more volume for fuel (or allowed for more strength which allowed for greater load? or both?)

 

[z42]

I know that I've mentioned the P-40 a couple of times, and even though it wasn't a great performer in the ETO (basically too slow for northern European operations, and not a good altitude performer even with the Merlin), it was cheap, simple (for a modern aircraft) and robust.

I've also mentioned the P-51, as it married advanced featured (mostly aero) into a relatively simple to produce and maintain airframe. Even the Lightweights (culminating on in the P-51H) took all of this a step further, and were optimized for both reduced weight and increased ease of maintenance for ground crews.

I think there is quite a lot of false economy in staring at the production cost of fighters too much. Case in point, should the US have mass produced more P-40'ies instead of the more expensive P-51? I think we can all agree that the answer is no. A more capable fighter increases the chance that the pilot manages to shoot down an enemy plane, and reduces the chance that the expensive and slow to train pilot is lost, in addition to the lost aircraft. That doesn't of course mean that an air force should happily buy whatever gold plated Rube Goldberg contraption the industry comes up with. The P-51 probably represents a pretty good compromise, in that it was designed for very high performance but did also make some minor sacrifices in the name of ease of manufacturing and maintenance (e.g. not going for elliptical airfoils).

To emphasize the importance of pilots, see the experience of the Finnish air force (FAF) in WWII, briefly touched upon in that other "Sten SMG" thread of yours. The FAF didn't have the luxury of choosing fighters, they pretty much had to do with whatever they could get their hands on. But they did succeed in having a good corps of pilots to drive those planes, managing to rack up an impressive K/D score against the Soviet Air Force. The Soviets apparently adopted the "zerg rush" strategy, sending lots of planes and pilots, succeeding in getting them killed in vast numbers. The same zerg rush vs. a smaller amount of better ones applies to aircraft as well, I think.

 

[MikeMeech]

You know if that book has info on either of the Miles M23 projects? The original M23 was a small, mostly wood(?) interceptor fighter powered by a Merlin or Griffon, and the M23A was a high altitude interceptor powered by a Merlin 60 series engine. As far as I know, though, these were just design exercises.

Hi
Yes it has, Chapter 14 has details on M.23 (4 pages) and Chapter 15 on M.23A (2 pages). The book also has other paper projects including the M.22A Twin Engined Fighter. Because this is a three volume work and a larger format it has much more detail (especially illustrations) than Don Brown's 'Miles Aircraft since 1925' Putnam work.

Mike

 

[MikeMeech]

I know that I've mentioned the P-40 a couple of times, and even though it wasn't a great performer in the ETO (basically too slow for northern European operations, and not a good altitude performer even with the Merlin), it was cheap, simple (for a modern aircraft) and robust.

Hi
Was the P-40 cheap? The French did not consider P-36 (Hawk 75) cheap. The unit cost quoted to the French by Curtiss was Fr 2,365,000 (in 1938/39), this was about twice the cost of a MS. 406 or MB-150 to produce for the French Air Force. However, they needed aircraft rapidly to try and keep up with the Germans and there were problems with the MB-150 so they paid up. The British could not supply many aircraft to the French when asked due to their own expansion and modernisation programme despite producing more aircraft than the USA at the time.

Mike

 

[BarnOwlLover]

P-36/P-40 was almost certainly less expensive than the P-51, which wasn't particularly expensive by Western Allies standards. And for the original Mustang Is the RAF and the Air Ministry asked for a unit price equal to about $40,000 USD at the time.

 

[Shortround6]

Prices for P-40s are all over the place. Unless you KNOW what the price per aircraft was you can't take the contract price and divide by the number of aircraft to get the price per aircraft.
Contract prices sometimes include spare parts. They include documentation (manuals and parts lists) and you have to be careful if the price includes the entire aircraft or just the price of the aircraft minus any "government furnished equipment" (GFE).
Once WW II got going the US Army was writing and printing a lot of the training manuals and parts manuals. Who paid for that in early foreign sales may change in the early years but with lend lease???

France had purchased for their first 200 planes the money value of 50 airplanes as spare parts. The book does not say if that was airframes or complete aircraft. The French were buying FN guns to arm them with and not using the standard French machine guns. How much other "stuff" was changed? Radios, instruments (or just got French lettering?) oxygen system etc.

Now the French planes and the American P-36s overlapped in production and I don't know how they did it in 1938-39. By the Spring of 1941 Curtiss had 7 production lines operating in parallel and it was fairly easy to keep the British aircraft separate from the US aircraft and even the Chinese aircraft.
In Sept/Oct there were meetings between the US and British and Curtiss to get rid of some of the differences (like size of the radio shelves and/or brackets for example) to streamline production. Sometimes things got screwed up. The Russians got a bunch of early P-40s with the wrong generators. which they promptly burned out grounding a bunch of planes until a priority ship was sent to Russia to replace them.

Pricing really needs accountants and contract lawyers to short out a quicky claim that plane X cost $43,256 actually doesn't tell us a whole lot without some context.

Edit:> Pricing between countries also gets tricky, France had playing games with the currency exchange rate (so had Germany) so one really has to be careful when comparing the "price" of US planes sold to France and the price of French built aircraft.

 

[glennasher]

I'm still trying to figure out what a "Sten SMG" aircraft is. Arming an aircraft with one Sten doesn't seem, er, prudent.

Cheap and easy to build and service, is my take on it. It kinda threw me at first, too, but I got it figured out. Sorta like today's Glock pistols versus a more complicated to build 1911 (I'm a solid, hardcore 1911 guy, personally).

 

[Thumpalumpacus]

Cheap and easy to build and service, is my take on it. It kinda threw me at first, too, but I got it figured out. Sorta like today's Glock pistols versus a more complicated to build 1911 (I'm a solid, hardcore 1911 guy, personally).

God, I hate jargon shorn of context. Just say what you mean, damn it.

 

[GrauGeist]

The P-51 didn't exists (or even the P-40) when the French were purchasing the Hawk 75.

So there is absolutely no way that one could compare the cost between the two...

 

[wuzak]

That's a lot of argument for one airplane that didn't make production. But, decently done, Tomo. It likely explains the lack of production which seems to be as you wanted it and as it happened.

I think the fact that both the Hurricane and Spitfire flew before the Venom was the reason that the Venom (nor any of its competitors) saw production.

I still think some air support would have been better than no air support in places that historically didn't have any.

There is a bit of crystal-ball work there. The Air Ministry did not know when war would occur, and may have considered there enough time to build sufficient aircraft (Spitfires and Hurricanes) to cover all bases by the outbreak of war.

 

[z42]

Prices for P-40s are all over the place. Unless you KNOW what the price per aircraft was you can't take the contract price and divide by the number of aircraft to get the price per aircraft.
Contract prices sometimes include spare parts. They include documentation (manuals and parts lists) and you have to be careful if the price includes the entire aircraft or just the price of the aircraft minus any "government furnished equipment" (GFE).
Once WW II got going the US Army was writing and printing a lot of the training manuals and parts manuals. Who paid for that in early foreign sales may change in the early years but with lend lease???

France had purchased for their first 200 planes the money value of 50 airplanes as spare parts. The book does not say if that was airframes or complete aircraft. The French were buying FN guns to arm them with and not using the standard French machine guns. How much other "stuff" was changed? Radios, instruments (or just got French lettering?) oxygen system etc.

Now the French planes and the American P-36s overlapped in production and I don't know how they did it in 1938-39. By the Spring of 1941 Curtiss had 7 production lines operating in parallel and it was fairly easy to keep the British aircraft separate from the US aircraft and even the Chinese aircraft.
In Sept/Oct there were meetings between the US and British and Curtiss to get rid of some of the differences (like size of the radio shelves and/or brackets for example) to streamline production. Sometimes things got screwed up. The Russians got a bunch of early P-40s with the wrong generators. which they promptly burned out grounding a bunch of planes until a priority ship was sent to Russia to replace them.

Pricing really needs accountants and contract lawyers to short out a quicky claim that plane X cost $43,256 actually doesn't tell us a whole lot without some context.

Edit:> Pricing between countries also gets tricky, France had playing games with the currency exchange rate (so had Germany) so one really has to be careful when comparing the "price" of US planes sold to France and the price of French built aircraft.

Indeed. And a war throws in additional spanners in the works. Does a war, or a threat of an imminent one, enable manufacturers to jack up prices to stratospheric levels? Or does the government order an indigenous manufacturer to produce at cost? etc. etc.

Perhaps a better approximation of the "true" cost of a plane (in terms of materials and manpower) would be to compare the number of man-hours it took to build? But even there one sees huge differences, e.g. I recall seeing figures showing that towards the end of the war the production process of the B-24 had been streamlined to the point it took a fraction of the man-hours it took in the beginning of production..

 

[BarnOwlLover]

The reason I named both threads as such is that the Sten does basically represent (as far as infantry weapons) the ultimate extreme as far as simple to produce, SHTF weaponry. Or as I heard someone put it in a review of the old PC game "Return to Castle Wolfenstein", "as close as a major power came to making a 'Fallout' pipe gun".

Obviously, any aircraft is going to be way more involved to make than a SMG that was able to be made from stamped sheet metal and a handful of easily machined parts that can be made for about $10 in 1942 with simple tools.

Of course, that being said, some combat planes were easier to make than others, but they still had to be capable of doing what they were intended to do to a specified degree. So here I'm asking what was the optimal trade off between production vs capability? This is different from the "what if" thread, which is entirely about emergency/SHTF/"panic" fighters. Though I do perhaps see where there might be some crossover in both threads.

 

[Shortround6]

Obviously, any aircraft is going to be way more involved to make than a SMG that was able to be made from stamped sheet metal and a handful of easily machined parts that can be made for about $10 in 1942 with simple tools.

And we also run into differences in tooling. The Sten gun could be turned out a shop the size of a garage with lathe and a welder (or perhaps the Welder was across the lane) as long as somebody was providing the rifled barrels or barrel blanks (30+ inch rifled tubes that could be cut into barrels). There are several different models of Sten, some used a lot less stamped sheet metal than others, some used a lot of tubing stock.

The US M3 Grease gun was very cheap.

But it required some medium sized sheet metal presses. And bit more welding.

It could be made very cheaply but you needed more plant investment. Even the grips are stamped sheet metal.

 

[GregP]

Cheap and easy to build and service, is my take on it. It kinda threw me at first, too, but I got it figured out. Sorta like today's Glock pistols versus a more complicated to build 1911 (I'm a solid, hardcore 1911 guy, personally).

They both shoot well.

The Glock will outlast the 1911 by a long way before the slide gets loose and needs to be looked at. I have one friend who shoots ina combat club and he has over 150,000 rounds through his Glock. It shoots perfectly fine even now.

But, I like them both. Add in a Sig, Beretta, Browning, and couple of others you have a good start on a collection.

 

[Clayton Magnet]

But, I like them both. Add in a Sig, Beretta, Browning, and couple of others you have a good start on a collection.

I can't get past the Glock grip angle, they just don't point where they are supposed to, for me. Give me a CZ (Sp01, P-10) all day.
As far as aircraft production costs are concerned, the 109 was probably the best bargain. Although, when you have slaves building your stuff, it would probably throw off the numbers