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LostCosmonaut

The Swedish AFV Thread: Not Just Strv 103s

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It's only a bit shorter than most Soviet tanks.  The big advantage of the configuration is that when it is hull down very little hull is exposed:

 

fP8oM1U.jpg

 

A hull-down T-55 has to expose more or less the entire turret because the gun is mounted at the bottom of the turret.  In theory, most NATO tanks save chieftain/chally/chally2 would need only to expose the upper 3/4 of the turret or so.

 

Swedes were big fans of external gun mounts for their TDs, of course.

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Interesting thing I found browsing the archives:

 

6TCQ6UT.jpg

 

That one on the left looks pretty comparable to a D-10, aside from being much heavier. (The ones on the right look like a different lower power 10.5cm gun).

 

Sadly there's not shit for info on the 10.5cm lvkan on the internet.

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On 10/30/2014 at 3:01 AM, Collimatrix said:

 

Time to break some of this down:

 

D4aPupV.jpg

 

Projected frontal silhouettes.  STRV 2000 T is the familiar one, STRV 2000 O is another proposed configuration with a completely external weapons mounting:

 

SXLkXXV.jpg

 

WSywd3W.png

 

Different configurations considered for STRV 2000, note that only one of the configurations had a 140mm gun.  Some of the others were based on the CV-90 chassis:

zdIcrwt.png

 

gX7Swot.jpg

 

Side armor configuration of the STRV 2000:

l7xXGIk.png

 

"Band" means track.

 

EkwLQVl.jpg

 

Overall armor layout.  You can see that side armor was prioritized.

 

cX6b0gX.png

 

Design of the ERA.

 

 

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26 minutes ago, Collimatrix said:

 

Time to break some of this down:

 

D4aPupV.jpg

 

Projected frontal silhouettes.  STRV 2000 T is the familiar one, STRV 2000 O is another proposed configuration with a completely external weapons mounting:

 

SXLkXXV.jpg

 

WSywd3W.png

 

Different configurations considered for STRV 2000, note that only one of the configurations had a 140mm gun.  Some of the others were based on the CV-90 chassis:

zdIcrwt.png

 

gX7Swot.jpg

 

Side armor configuration of the STRV 2000:

l7xXGIk.png

 

"Band" means track.

 

EkwLQVl.jpg

 

Overall armor layout.  You can see that side armor was prioritized.

 

cX6b0gX.png

 

Design of the ERA.

 

 

Translation:

Zzor3pT.png

 

 

Gd97aGM.png

 

 

QEtocyw.jpg

 

 

ADoHKKn.png

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For the Strv 2000 O, it looks like the gun would have to be traversed back to the 12 o'clock position in order to be reloaded. I suppose that the gun itself can be lowered, backwards, so as to bring the breech closer to the autoloader arm? (or even to mate the breech with the autoloader hatch, thus preventing the ammunition from being exposed)

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23 minutes ago, Renegade334 said:

For the Strv 2000 O, it looks like the gun would have to be traversed back to the 12 o'clock position in order to be reloaded. I suppose that the gun itself can be lowered, backwards, so as to bring the breech closer to the autoloader arm? (or even to mate the breech with the autoloader hatch, thus preventing the ammunition from being exposed)

udes_103_ovanpalagrad.jpg

 

" En 10,5 cm kanon monterades ovanpå Mardern i ett enmanstorn. Med denna rigg UDES 19 genomfördes ett flertal olika försök – körning, skjutning, med mera.

Det gjordes egentligen två riggar för UDES 19. Utöver kör- och skjutriggen tillverkades även en laddrigg. På dessa genomfördes kör-, skjut-, observations-och laddförsök. Laddriggen testade principen att låta en laddpendel som roterar runt samma axel som kanonen föra skotten ett och ett från magasinet till kanonen.

Konstruktionen visade sig fungera bra och vara så robust att varken snö eller de grenar man testade med (upp till 5 cm) tjocka utgjorde något hinder för funktionen, däremot sågs det finnas risk att skräp följde med skotten in i kanonen. Man testade dock inte känsligheten för beskjutning.

Under skjutförsök bekräftades att det gick snabbare att inrikta kanonen - detta eftersom den har lägre massa än ett vanligt torn. Dock fick riggen långa skottider som berodde på dåligt fininriktningssystem.

Parallellt testades även denna princip med ovanpålagrad kanon på ett chassi till Strv 103. "

 

Translation:

" A 105mm canon was mounted on top of a Marder AFV in a one-man turret. With this rig, UDES 19 completed several different tests - driving, firing and more.

It is actually two rigs for UDES 19. For driving- and shooting-rig a loading rig is added. Driving, firing, observation and loading test are done on these rigs. The loading rig is to test the principle that a loading pendulum that rotates around the same axis as the canon can feed ammunition from the magazine to the cannon. 

This system appeared to work well and was so robust that neither snow or branches that was tested (up to 50mm) thick made a hindrance for the system, however, there is a risk of rubbish coming with the ammunition into the cannon. Therefor, the sensitivity to firing was not tested. 

In the firing trials in was found that the cannon was faster at aiming, because of the lighter tower. However, the rig high aiming time was thought to be because of bad FCS.

In parallel this principle was tested on a chassis of the Strv 103."

 

Source:

http://www.ointres.se/udes.htm

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6 hours ago, Collimatrix said:

Overall armor layout.  You can see that side armor was prioritized.

 

Not really. It wasn't prioritized, but the larger coverage was necessary due to the front-mounted engine. Ballistic skirts and armor modules still cover only the frontal 60° arc.

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12 hours ago, SH_MM said:

 

Not really. It wasn't prioritized, but the larger coverage was necessary due to the front-mounted engine. Ballistic skirts and armor modules still cover only the frontal 60° arc.

strv_2000_hotbild-web.jpg

 

" De tekniska studierna delades upp i kompetensuppbyggande studier och försök, konceptstudier samt projektstudier. Fysiskt skydd kom att prioriteras före beväpningssystem, ledningssystem och rörlighetssystem. Tre huvudkrav kom att bli konceptstyrande:

  • Skjutning under gång varvet runt (360º) med huvudvapnet
  • Direktutblick för vagnchefen från vagnens högsta punkt
  • Överlevnad för vagn och besättning vid en träff i ammunitionslagringen

Vidare beaktades de typiskt svenska förhållandena som normalt resulterade i speciella krav på försvarsmaterielen – den korta värnpliktsutbildningen följd av korta repetitionsövningar (dvs materielen måste vara lätt att handha) och det faktum att materielen under större delen av sin livslängd skulle ligga i mobiliseringsförråd med ett minimum av underhåll.

 

 

 

Skydd

I projekt Strv 2000 tillmättes skyddet i vid bemärkelse stor betydelse – eller stridsvagnens överlevnadsförmåga vad avser skydd mot upptäckt-identifiering-träff, skydd mot verkan och skydd mot efterverkan. Kraven sattes mycket högt både vad gäller låga signaturer inom våglängdsområdena för IR och radar, men framförallt för det ballistiska skyddet. Dessa inkluderade mycket förutseende krav på skydd mot minor och takverkande stridsdelar.

strv_2000_kompositpansar-web.jpg

Grundprincipen för vagnens uppbyggnad var ett minimiskrov i pansarstål som var tillräckligt tjockt för att kunna ta upp krafterna vid körning och skjutning. Det skulle också kunna ta upp de krafter som en yttre skyddsmodul kunde åstadkomma då den träffats.

strv_2000_framre_skydd_sida-web.jpg strv_2000_amlagring-web.jpg

I det fall den yttre skyddsmodulen använde sig av principen med ett spontaninitierat tungt explosivt reaktivt pansar (t ex i kompositionen 15/3/9) – effektivt inte bara mot riktad sprängverkan, utan även kinetisk energi – kunde dessa krafter på grundstrukturen bli relativt stora. De försök som gjordes mot frontalt monterade moduler med denna typ av skydd visade att det var möjligt att kraftigt störa en penetrerande pilprojektil.

strv_2000_tap-web.jpg

Tanken var också att Strv 2000 skulle använda en stor andel keram i skyddskonstruktionen. Det faktum att den totala andelen keram skulle komma att uppgå till flera ton i respektive stridsvagn gjorde att ett det så kallade Skyddskeramprojektet startade upp 1988. Under ett par års tid gjordes försök med många olika typer av keram - Al2O3(aluminiumoxid), B4C (borkarbid) och TiB2 (titanborid) – men trots ett brett deltagande från svensk industri, FOA och FMV, blev det inte så mycket mer än en medioker referenskeram.

keramprov.jpg

Inspirerade av den valda skyddslösningen i den amerikanska stridsvagnen M1A1 DU där Chobhampansaret uppgraderats med skikt av utarmat uran, gjordes provskjutningar i Sverige även mot denna typ av material. Resultaten visade på möjligheten att nå bättre skyddsprestanda om volymen och inte vikten var gränssättande.

amlagringsprov.jpg

Stor möda lades även på att åstadkomma en från besättningen separerad ammunitionslagring som skulle tåla såväl krutbrand som en detonation efter direktträff på en RSV-stridsdel med övertändning som följd. Den lösning som utarbetades fungerade och hade stora likheter med motsvarande utrymmen i Leopard 2 och M1A1 med så kallade ”blow off panels”, men hade en utvecklad princip för att förhindra total övertändning med total utslagning som följd. Skotten var placerade längst bak i chassiet. "

 

Translation:

strv_2000_hotbild-web.jpg

" The technical studies are divided up into competence building studies and trials, concept studies and project studies. Physical armor is prioritzed over weapon systems, FCS and mobility systems. Three main requirements have steered the concept:

 

        - Firing while on the movie, 360 degrees with the main weapon.

        - Direct sight for the vehicle commander from the tanks highest point. 

        - Survival of the tank and crew in case of a hit to the ammunition storage. 

 

Furthermore, the typical Swedish environment is considered, which normally results in special requirements for defense materials - the short conscription followed by short repletion exercise (meaning that the material needs to be easy to handle) and the fact that the material in bigger parts of its lifetime will be located at mobilization storage with a minimum of maintenance. 

 

Armor:

In project Strv 2000 is armor of the highest importance - or the tanks survival chance against discovery - identification - hit, protection against impact, after armor protection. High requirements are sett for a low signature in the visual spectrum, for IR and for radar, men but most of all the armor. These include requirements for mine protection and roof armor. 

 

QEtocyw.jpg

 

 

The principle of the tank construction is a minimal hull of armor steel, made strong enough to absorb the force when driving and firing. It should also be able to take up the force that a outer armor module would achieve when hit.

Gd97aGM.pngstrv_2000_amlagring-web.jpg

 

 

In the case of the outer armor module, the use of the principle with a spontaneously initiated heavy explosive reactive armor (composition 15/3/9) - effective not only against directed explosive force (I assume HEAT) but also kinetic energy - could these forces on the hull be reality large.

ADoHKKn.png

 

 

It was also thought that Strv 200 would use a large amount of ceramics in the armor construction. The fact that a big portion of ceramics would come to make up several tons in the tank in question, caused the so called ceramic armor project to be started in 1988. In a couple of years time a few tests were done with several different ceramics - Al2O3(aluminium oxide), B4C (boron carbide) and TiB2 (titan boride) - but even with a board cooperation between Swedish industry, FOA and FMW, the ceramics turned out the not be much more than a mediocre reference ceramics. 

keramprov.jpg

 

Inspired by the armor solution chosen by the US tank M1A1, in which the Chobham armor was upgraded with a layer of depleted uranium, a firing trial was held in Sweden against this type of material. The results showed a possibility of better armor performance if volume and not the weight was the restricting factor.

 

 

amlagringsprov.jpg

 

A lot of effort was put into producing the ammunition storage, separated from the crew, which can take a direct hit and detonation from a ATGM. The solution developed was similar to the Leopard 2 or M1A1 with their so called "blow off panels", but was also developed to stop a chain reaction from detonating all the ammunition. The ammunition was placed in the hull rear. "

 

I translated the section covering the armor for you guys. Though I do not see anything indicating that the front engine required longer side armor. The requirements state the coverage, regardless of a front engine.  Though the coverage required is similar to the M1A2 and Leopard 2's turret. 

 

I can translate more if anyone is interested.

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8 hours ago, Xoon said:

The results showed a possibility of better armor performance if volume was not a restricting parameter.  

 

That is not the correct translation of "Resultaten visade på möjligheten att nå bättre skyddsprestanda om volymen och inte vikten var gränssättande". It should be "The results showed the possibility of better armor performance if volume and not weight ("och inte vikten") was the resrtricting factor".

 

8 hours ago, Xoon said:

I translated the section covering the armor for you guys. Though I do not see anything indicating that the front engine required longer side armor. The requirements state the coverage, regardless of a front engine.  Though the coverage required is similar to the M1A2 and Leopard 2's turret. 

 

The armor is designed to protect the crew compartment along the 60° arc against ATGMs and APFSDS ammo. Let me illustrate this with a poorly made drawing:

 

F8zAhGn.jpg

 

Both tanks have the same protection level for the crew compartment (driver's compartment + turret ring), but with a front mounted engine, longer side skirts are required to cover the crew compartment (because it starts behind the enigne). I.e. heavy ballistic skirts and armor modules covering the complete length of the engine compartment have to be added to reach the same level of protection along the frontal arc. This is one of the reasons why Germany and the United States both decided to not build tanks with front-mounted engines, after evaluating the concept and even creating prototypes for testing this interior layout.

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1 hour ago, SH_MM said:

That is not the correct translation of "Resultaten visade på möjligheten att nå bättre skyddsprestanda om volymen och inte vikten var gränssättande". It should be "The results showed the possibility of better armor performance if volume and not weight ("och inte vikten") was the resrtricting factor".

Thank you for the correction, late night translation is not my strong suite. 

 

1 hour ago, SH_MM said:

The armor is designed to protect the crew compartment along the 60° arc against ATGMs and APFSDS ammo. Let me illustrate this with a poorly made drawing:

 

F8zAhGn.jpg

 

Both tanks have the same protection level for the crew compartment (driver's compartment + turret ring), but with a front mounted engine, longer side skirts are required to cover the crew compartment (because it starts behind the enigne). I.e. heavy ballistic skirts and armor modules covering the complete length of the engine compartment have to be added to reach the same level of protection along the frontal arc. This is one of the reasons why Germany and the United States both decided to not build tanks with front-mounted engines, after evaluating the concept and even creating prototypes for testing this interior layout.

Good point.

But one thing, doesn't the Strv 2000 have thicker sideskirts than the M1A1?

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On 10/28/2018 at 1:06 PM, Xoon said:

But one thing, doesn't the Strv 2000 have thicker sideskirts than the M1A1?

 

Yes, it does. There also seems to be a general difference in armor technology though (ceramic armor + ERA on the Strv 2000 proposals vs NERA on the Abrams). The Strv 2000 should be better protected around the hull, yet if the same armor (or thicker NERA) was added to the M1 design, it would have the same protection level for the crew compartment at a lower weight.
 

The M1's hull side armor layout isn't really optimized for frontal protection, as the side skirts are longer than necessary in order to cover the fuel tanks and the hull ammo rack located behind the turret ring. The additional surface means that for a given weight, less protection can be achieved per surface area. On the right side of the tank, the skirts are actually extended beyond the turret ring, so the overall length is similar to the Strv 2000's in this location.

 

XI0Ga1F.jpg

 

The Strv 122's side skirts provide protection against single-stage shaped charge warheads with 165 mm diameter (1,400 mm penetration into steel) at impact angles up to 25° (covered frontal arc is therefore 50°) and 120 mm APFSDS ammo with 700 mm penetration at impact angles up 17.5° (covered frontal arc is therefore 35°). That is below the required armor coverage for the Stridsvagn 2000, but AFAIK it isn't known what types of APFSDS ammo and ATGMs were used for the Strv 2000's hull (for the Strv 122, the official requirement for the tender was only protection against 105 mm APFSDS and 143 mm shaped charge warheads for the hull).

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6 hours ago, SH_MM said:

- snip - 

 

I know that the armor layout of the Strv 122 is less efficient. I was just wondering about this:

On 10/27/2018 at 7:12 PM, Collimatrix said:

Overall armor layout.  You can see that side armor was prioritized.

 

On 10/28/2018 at 1:28 AM, SH_MM said:

 

Not really. It wasn't prioritized, but the larger coverage was necessary due to the front-mounted engine. Ballistic skirts and armor modules still cover only the frontal 60° arc.

 

On 10/28/2018 at 1:06 PM, Xoon said:

But one thing, doesn't the Strv 2000 have thicker sideskirts than the M1A1?

 

6 hours ago, SH_MM said:

 

Yes, it does. There also seems to be a general difference in armor technology though (ceramic armor + ERA on the Strv 2000 proposals vs NERA on the Abrams). The Strv 2000 should be better protected around the hull, yet if the same armor (or thicker NERA) was added to the M1 design, it would have the same protection level for the crew compartment at a lower weight.

 

I am confused here. Coli states "You can see that side armor was prioritized", referring to the hull side armor schematic.  Then, you say : "It wasn't prioritized". And then you say : "The Strv 2000 should be better protected around the hull"

 

Since the Strv 2000 should be better protected around the hull, would it not makes sense to think that the engineers prioritized side armor? 

 

I am not trying to strawman you or anything like that. It is just that your statements confuse me a little and I was wondering if you could clarify a bit. 

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14 hours ago, Xoon said:

I am confused here. Coli states "You can see that side armor was prioritized", referring to the hull side armor schematic.  Then, you say : "It wasn't prioritized". And then you say : "The Strv 2000 should be better protected around the hull" 

  

Since the Strv 2000 should be better protected around the hull, would it not makes sense to think that the engineers prioritized side armor?  

 

You should look at it relative to its peers; that a newer tank reaches a higher level of protection than an older design is nothing special. IMO one could only say that side armor was prioritized, if more weight was invested into the side armor relative to the frontal armor (meaning the side armor is prioritized over the frontal armor) or greater coverage is demanded: prioritizing would mean to invest more weight into the side armor to either reach a higher protection level (larger frontal arc reaches same protection as the frontal armor) or armor coverage (which one can consider indepedent of timeframe). As we can see by looking at the requirements for the Abrams, it was designed with protection against tank rounds and ATGMs along a 50° arc. 50° is a bit smaller than 60°, which was common on other designs of the time (see German, French & British requirements for their third generation MBTs).

If we account for the technology differences,  the Stridsvagn 2000 wasn't designed to reach a high level of protection along a greater frontal arc than existing tanks, so side armor wasn't prioritized compared to other tanks.

 

The only reason why one could claim that the Strv 2000 prioritizes side armor compared to the M1 Abrams is the fact that the hull at areas covered by the ballistic skirts is capable to resist certain types of handheld anti-tank weapons (RPG-7, Carl Gustav?) at perpendicular impact angle, but IMO that is only a by-product of the higher protection level required for the frontal arc. It is similar to the Leopard 2A5, where the area covered by ballistic skirts is capable to resist the basic RPG-7 rounds, even though it wasn't nedessarily designed to do so.

 

If you consider that the Stridsvagn 2000 was an unfinished development project and originally meant to enter service around the year 2000, the it would make more sense to compare it to contemporary projects (i.e. the "lost generation" of Cold War prototypes and testbeds made for the 2000s), then the Stridsvagn 2000 doesn't seem to have particular thick side armor/good armor coverage at the hull.

 



a1a6848f888fed0b54d65d4c04597548.png

52O9p.jpg

AfjWc.jpg

 

The main reason why comparing the M1A2 Abrams' and Stridsvagn 2000's hull armor isn't a good idea, is the lack of upgrades for the (side) hull armor of the former MBT. Based on footage from the production of M1A1s for Egypt and factory footage from the United States, the basic hull armor and side skirts still have the same thickness/layout as used on the original production model of the Abrams in 1980.

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21 hours ago, SH_MM said:

 

You should look at it relative to its peers; that a newer tank reaches a higher level of protection than an older design is nothing special. IMO one could only say that side armor was prioritized, if more weight was invested into the side armor relative to the frontal armor (meaning the side armor is prioritized over the frontal armor) or greater coverage is demanded: prioritizing would mean to invest more weight into the side armor to either reach a higher protection level (larger frontal arc reaches same protection as the frontal armor) or armor coverage (which one can consider indepedent of timeframe). As we can see by looking at the requirements for the Abrams, it was designed with protection against tank rounds and ATGMs along a 50° arc. 50° is a bit smaller than 60°, which was common on other designs of the time (see German, French & British requirements for their third generation MBTs).

If we account for the technology differences,  the Stridsvagn 2000 wasn't designed to reach a high level of protection along a greater frontal arc than existing tanks, so side armor wasn't prioritized compared to other tanks.

 

The only reason why one could claim that the Strv 2000 prioritizes side armor compared to the M1 Abrams is the fact that the hull at areas covered by the ballistic skirts is capable to resist certain types of handheld anti-tank weapons (RPG-7, Carl Gustav?) at perpendicular impact angle, but IMO that is only a by-product of the higher protection level required for the frontal arc. It is similar to the Leopard 2A5, where the area covered by ballistic skirts is capable to resist the basic RPG-7 rounds, even though it wasn't nedessarily designed to do so.

 

If you consider that the Stridsvagn 2000 was an unfinished development project and originally meant to enter service around the year 2000, the it would make more sense to compare it to contemporary projects (i.e. the "lost generation" of Cold War prototypes and testbeds made for the 2000s), then the Stridsvagn 2000 doesn't seem to have particular thick side armor/good armor coverage at the hull.

 

 

  Reveal hidden contents

 

 


a1a6848f888fed0b54d65d4c04597548.png

52O9p.jpg

AfjWc.jpg
 

 

 

 

The main reason why comparing the M1A2 Abrams' and Stridsvagn 2000's hull armor isn't a good idea, is the lack of upgrades for the (side) hull armor of the former MBT. Based on footage from the production of M1A1s for Egypt and factory footage from the United States, the basic hull armor and side skirts still have the same thickness/layout as used on the original production model of the Abrams in 1980.

Thanks for taking the time to clarify. 

I really appreciate it.

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      SAAB 1371 (1300-71), a proposal which made it as far as wind tunnel testing.
       
      As can be seen from the previous drawings, many of the designs were planned to have two engines. As with other Swedish aircraft of the time, the A36 was planned to use license built British engines. Among the engines considered were the de Havilland Gyron and smaller Gyron junior. However, at some time early in the development of the program, it was decided that the aircraft would be powered by the Bristol Olympus turbojet, the same engine that powered the British Vulcan bomber. However, for use in a supersonic aircraft, it would have required modification, such as the fitting of an afterburner, and a new intake. (The Olympus was eventually developed for use in supersonic aircraft, such as the TSR-2 and Concorde.) With such a large and powerful engine, it became apparent that only a single engine would be needed in the A36.
       
      At such high speeds, the A36 would have experienced significant aerodynamic heating. This concerned Swedish engineers, who were afraid that the heat would damage contemporary nuclear weapons (or even lead to them detonating prematurely). As a result, it was decided that the payload would be carried within an internal weapons bay. This would reduce drag, improving performance, but it would also limit payload, while decreasing the internal volume available for fuel, avionics, and other systems. By the time the A36 design had progressed  to the 1376 and 1377 configurations, payload was determined to be a single 800 kilogram nuclear weapon, carried internally. This is roughly comparable in size to the American Mark 7 bomb, deployed tactically around the same time. As far as I know, no provision was ever made for the A36 to have air-to-air capabilities.
       
      By 1957, the design of the A36 (which had by now received a formal Swedish Air Force designation) was almost finalized.
       
      (SAAB 1376, with chin intake)

       

      (Drawing of SAAB 1377 with dorsal intake, similar to YF-107)
       
      Most documents show the 1376 as the chosen design. 1376 was a moderately sized aircraft, somewhat smaller than the American F-105 (which had a similar role to the A36). The wing was a conventional delta with 62 degree sweep, which would have given good performance in the supersonic regime. I am uncertain whether the A36 would have utilized a variable geometry inlet. A fixed inlet would have had to be optimized for a certain speed; this would mean that the A36 would have been inefficient at low Mach numbers, or been had it speed limited by the inlet design. (Read more about inlet design here).
       
       
      Although work on the A36 was progressing well, by 1957 it was apparent that Sweden could not afford to develop the A36, nuclear weapons, and other vital defense programs. As the A36 would have been relatively lacking in conventional capability, it was decided to cancel the program. (Ultimately, the nuclear weapons program would be shut down during the 1960s as well). Some of the money saved was used to develop the A37 Viggen, which proved to be a competent multirole aircraft during the 1970s and beyond. Ultimately, while it would have been interesting from a technological standpoint to see the A36 fly, its cancellation was probably the right choice.
       
      I have not found any documents showing that the A36 was ever given a name (such as 'Draken' for the J35). Occasionally references can be found to the A36 'Vargen' (Wolf) online, but it appears that these are the inventions of either modeling companies or someone with an overactive imagination.
       
      A36 (1376 design) specifications (approximate):
      Length: 17m
      Wingspan: 9.6m
      Height: 2.5m
      Wing Area: 54m2
      Empty Weight: 9000 kg
      Max Weight: 15000 kg
      Wing Loading at Max Weight: 280 kg/m2
      Payload: 800 kg
      Max Speed: Mach 2.1
      Ceiling: 18000m
      Combat Radius: 410km (?)
      Crew: 1
      Engine: 1x Bristol Olympus Turbojet
       
       
       
       
       
      Sources:
      http://u-fr.blogspot.com.br/2010/12/cancelled-saab-aircraft-projects.html
      http://www.secretprojects.co.uk/forum/index.php/topic,683.0.html
      http://forum.valka.cz/topic/view/55568/SAAB-A-36
    • By LostCosmonaut
      Numerous countries attempted to develop turbojet engines in the post-WW2 period. There were many failures: the J40, TR-1, and others. One of these unsuccessful engines was the Swedish STAL Dovern.
       

       
       
      Attempts to develop an indigenous jet engine began at STAL (Svenska Turbinfabriks AB) in the late 1940s. The first engine developed by STAL was the Skuten, in 1948. This was a small, axial flow turbojet with 6 combustion chambers producing roughly 6.2 kN of thrust. The Skuten was intended primarily as a ground-run technology demonstrator, I am not aware of any attempts or plans to fit it to an aircraft. In the meantime, the Swedes used British engine designs for their aircraft, such as the De Havilland Ghost on the J29.
       
      Work on the STAL Dovern began in the late 1940s, and from the start, the engine was intended for operational use. The intended recipient was the SAAB 32 (Lansen) attack aircraft, then under development. This would require a much more powerful engine than the Skuten, and so the Dovern was itself much larger. Like the smaller engine, the Dovern was built as an axial flow turbojet. However, additional combustion chambers were added, bringing the total to nine. This, along with a large increase in the dimensions of the engine, resulted in the Dovern having a design output of over 32 kN. This was significantly more than the De Havilland Ghost powering the J29 at the time.
       
      The STAL Dovern was first ground tested in February 1950, roughly two years after development began. By this time, the engine had matured into an axial flow design with a nine-stage compressor section, and nine combustion chambers arranged in a circular manner. Pressure ratio was about 5.2, superior to the Ghost, but inferior to the British Avon also under development in the same time period.
       
      (a picture from 1954 Flight Global magazine comparing the Dovern and Ghost)

       
      After about 3,000 hours of run time, a Dovern prototype was fitted to a Swedish Avro Lancaster (Tp 80) for further testing.
       

       
      Testing of the engine in this manner began in June 1951, and revealed some issues. At certain power settings, the engine would suffer compressor surging, causing a loss of power and potential damage to the engine. Numerous redesigns of the compressor section somewhat alleviated the problem, though did not manage to cure it entirely.
       
      By 1954, the Dovern had accumulated over 4,000 hours of runtime, including about 300 on the Lancaster testbed. An afterburning variant had also been developed, producing  45 kN. However, the engine was still not fully ready, and by this point the Lansen had already flown with an Avon engine fitted. As a result, it was decided to cancel the Dovern program, and instead use the Avon engine in both the Lansen and upcoming Draken (J35). (Some sources say that the Dovern was cancelled when it caught fire and destroyed the Lancaster test aircraft. However, this actually happened in 1956 while testing the RM-6/Avon, at which point the Dovern was already cancelled.) 16 units had been produced. An advanced version, called the Glan, had been under development for use in the Draken. It was also cancelled.
       
      From this point, Swedish aircraft designs would use foreign engines. Though the Dovern was not fully developed, it cannot be said to be a failure for the Swedish aerospace industry. Producing world-class jet engines is highly difficult, requiring large amounts of experience and supporting industry. Only a few nations are truly capable of doing so even now (US, UK, France, Russia, and arguably China). For a country as small as Sweden, having an indigenous jet engine industry would be a truly Herculean feat.
       
      Sources:
       
      https://www.flightglobal.com/pdfarchive/view/1954/1954%20-%201015.html
      http://www.x-plane.org/home/urf/aviation/text/reamotorer.html
      http://en.valka.cz/topic/view/184837/SWE-STAL-Dovern
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