Skip to comments.The FReeper Foxhole's TreadHead Tuesday - Stridsvagn 103 (Swedish S-Tank) - June 8th, 2004
Posted on 06/08/2004 12:00:10 AM PDT by SAMWolf
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The Swedish S-Tank was developed through both a prototype and pre-production vehicle testing program in the early 1960s and reached the armored troops in mid 1967. It is probably one of the most unique AFV designs of the modern tank era, utilizing a number of different approaches to the primary problems of firepower, protection and mobility. Even though the S-Tank has been replaced in front line service by the German produced Leopard 2, the S-Tank is destined to be remembered as one of the most interesting AFV designs of the Cold War period.
The S-Tank designers, lead by Sven Berge as the head of the tank design section of the Vehicle Division of the Swedish Army Ordnance, were interested in solving a number problems faced in AFV design sections in the world. First, they were driven to provide the lowest profile possible to decrease the probability of the AFV being sighted and hit by opponent forces. This required the removal of the traditional turret and mounting of the main weapon directly in the hull of the machine, reducing the total height to 1.9 meters. With this done, the next problem was aiming the now fixed weapon, and a complicated system of steering and suspension were developed to allow the entire vehicle to aim at a target. With a stationary gun mount in the hull, an autoloader could be fitted and the typical fourth crew member/loader could be eliminated entirely, reducing the crew to three. Finally, by placing the tank engine(s) in the front of the AFV, extra protection of the vulnerable frontal arc could be increased. The results of this planning are shown in this sketch of the prototype tank, similar in most respects to production vehicles from A to C models.
The driver/gunner's seat is located to the left in the hull with the radio operator directly behind him and facing the rear. To the right in the hull is the commander with a revolving cupola over head. His seat is slightly elevated above the other crew members to better use the cupola. The main gun tube effectively divides the fighting compartment in half, ending with the breech at the rear of the tank. Both driver/gunner and commander have controls for driving and aiming/shooting the weapons, the commander's controls over-ride the driver/gunner. The gun is manufactured by Bofors and is a L74 105mm weapon very similar to the British L7 gun fitted to the Centurion, also used by the Swedish army in limited numbers at the time. This allowed the S-Tank to use the same ammo, although its gun tube is longer and therefore provides a higher velocity for the rounds which equates to better hitting power.
It takes only 15 minutes to load the 25 rounds/bin by two soldiers, which is very quick in comparison to typical tanks of the time. The twin ammo storage bins feed the hydraulic auto-loader and the main weapon passes right through the tank, ending in the breech placed directly above and between the ammo bins. Spent casings are ejected through a small port on the back plate of the tank, which eliminates smoke buildup in the tank. The engine compartment access plates dominate the entire front armor slope (there are actually three plates to take up this space, one bolted up the center under the gun and two hinged hatches on either side). The fuel cells occupy the space outside the fighting compartment and under steel along both side sponsons.
Both driver/gunner and commander are equipped with a unique control box for steering and firing the main gun. The radio operator also has rudimentary driving controls and the S-Tank can travel backwards just as well as forwards. The entire box pivots along the vertical axis, which in turn rotates the tank by hydrostatic steering. Rotating the hand grips (motorcycle style) elevates and depresses the hydro-pneumatic suspension and thus controls elevation of the weapon through vehicle tilt. The push buttons on the control are for loading and firing the main weapon and auxiliary MGs. The gun can fire 15 rounds per minute--typically one bin is filled with HE and smoke rounds and the other with AP. A Jungner OPS-1 combination periscope and sight is used for both the driver/gunner and commander with contains a unity magnification prismatic periscope with a wide 102 degree field of vision. This is combined with a binocular sight with X6, X10 or X18 magnification. The driver/gunner periscope is fixed in position but the commander's rotates with his powered cupola and is stabilized in elevation. The cupola also mounts four periscopes and there is one for the driver/gunner and two others facing the rear for the radio operator.
The engine, or actually engines, are of two different types. On the left is a Rolls Royce K60 diesel and the Boeing 502-10MA gas turbine is on the right. Both are connected to a Volvo hydro-kinetic torque converter automatic transmission closest to us. The transmission has two forward and two reverse speeds, one of the forward selections is higher geared for road travel and the other is lower for cross country. The twin power plants were planned to allow the vehicle to cruise with the economic diesel pushing the AFV along and then, during periods of high power needs, the turbine is switched on. The gas turbine also can be used as a starting engine for the diesel during extreme cold weather and the twin engine idea also allows either one to be used during an emergency or failure of the other unit.
The diesel is a 6-cylinder opposed-piston water-cooled two-stroke unit, which was developed to a British Army requirement (used for the FV432 APC and FV433 Abbot SPG) and develops 240bhp. The gas turbine (without heat exchanger) is compact and proven, being used in quantity by the US Navy where diesel/gas turbines do most of the heavy marine work. The turbine produces 330bhp, but provides more power than a piston engine for its size and weight. The large amount of air necessary for the turbine is ducted through large access gratings for both intake and exhaust at the left of the AFV (see the drawing above) while the diesel intake and exhaust are to the right. The second production series of the S-Tank, known as 103B has the original turbine replaced by a more powerful Boeing 553, develops 490bhp and has really improved the performance of the tank. Maximum speed was increased to 50km/h. The 103C currently in use has raplaced the original diesel with a Detroit Diesel D6V-53T, providing 300bhp. Along with the new diesel came a new three step automatic gear box and other changes.
Strv 103 weighs 39.7 tonnes and has a crew of three: commander, driver, also operating as gunner, and the radio operator, also function as driver when the tank is going in reverse. Maximum road speed is 50 kph. On-road and off road ranges are 390 and 150 km, respectively.
Stridsvagn 103C has recently been phased out and replaced by Stridsvagn 121 and 122 (Leopard 2).
Sweden has never been afraid to follow its own path on defence matters, and nowhere is this more apparent than with the radical S-Tank, more officially known as the Strv 103. In essence a super self-propelled gun, the S-Tank was armed with a 105 mm gun mounted rigidly in an extraordinarily low, heavily sloped hull; in order to train the gun, the entire vehicle has to be moved both in traverse and elevation. Due to the extreme importance of mobility, the S-Tank was fitted with two engines, one an auxiliary gas turbine to provide emergency power.
Who They Are: Operation: Stitches Of Love was started by the Mothers of two United States Marines stationed in Iraq.
What They Are Doing: We are gathering 12.5"x12.5" quilt squares from across the country and assembling the largest quilt ever produced. When completed we will take the quilt from state to state and gather even more squares.
Why They Are Doing This: We are building this quilt to rally support for the Coalition Forces in Iraq and to show the service members that they are not forgotten. We want the world to know Nothing will ever break the stitches that bind us together as a country.
Ideas to start a local project:
Obtain enough Red, White and Blue material (cloth) for a 12.5 x 12.5 quilt square.
If you have someone in your family that sews, make it a weekend project and invite neighbors to join you.
Consider this tribute as a project for your civic group, scouts, church or townhall group.
Locate an elementary school with an after school program in your neighborhood or locate an after school program in your neighborhood not attached to a school and ask if you could volunteer one or two afternoons and create some squares with the kids.
Invite some VFW posts to share your project in honor of their post.
Send us firstname.lastname@example.org for digital photos of in progress and finished project for various websites, OIFII.com and the media.
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Good night Snippy. I'm impressed by your ability to find mini-graphics of the subject tank. ;-)
I learned from one of the greatest scroungers around. :-)
1.9 meters is shorter than I am (193 cm or 6'4").
Front engine is the way to go.
Turns out the armor stinks. A more normal drive train and a sturmgeshutz type traverse and elevation would have lowered the rig maybe 6 to 9 inches and would have left weight for armor. A modern Hetzer would have been more practical.
Cool a thread on the ol "S" tank....
Last night shift bumperoooni for the next two weeks...YEAHHHH
Good morning, Snippy and everyone at the Foxhole.
Carbs, usless PC carb calories to start the day...yummy.
On This Day In History
Birthdates which occurred on June 08:
1625 Giovanni Domenico Cassini discovered 4 satellites of Saturn
1813 David D Porter US Admiral (Civil War)
1829 Sir John Everett Millais England, painter (Order of Release)
1847 Ida Sazton McKinley 1st lady
1867 Frank Lloyd Wright Richland Center, Wisc, master builder
1914 Joseph de Pietro US, 56kg weightlifter (Olympic-gold-1948)
1916 Francis Crick codiscovered DNA's structure (Nobel 1962)
1917 Byron R (Whizzer) White Ft Collins CO, NFLer/Supreme Court Justice
1918 Robert Preston Newton MA, actor (Music Man, Mame, Last Starfighter)
1925 Barbara Pierce Bush Rye NY, 1st lady (1989- )
1925 Eddie Gaedel 3'7" St Louis Browns pinch-hitter (he walked)
1929 Jerry Stiller Bkln NY, comedian/actor (Stiller & Meara, Hairspray)
1933 Joan Rivers Brooklyn, comedian (The Late Show, Hollywood Squares)
1937 Bruce McCandless II Boston, Cap USN/astronaut (STS 41B, STS-31)
1939 Herb Adderley Phila, NFL hall of famer (Packers, Cowboys)
1940 Nancy Sinatra Jersey City, singer, her boots were made for walkin'
1944 William Royce "Boz" Scaggs Dallas Tx, rocker (Steve Miller Band)
1950 Alex Van Halen drummer (Van Halen-Jump, 1984)
1958 Keenen Ivory Wayans comedian (In Living Color)
Hiya Sam. Interesting design concept.
ACK!!! I forgot to ping ya'll to #16.
Good morning PE. Thanks for the lovely Flag-o-gram.
Hope all is well with you and family.
If the roof doesn't leak, it's not daring enough.
Thanks. Yes, things are going quite well.
We were rainy and cold on sunday (in the 60's) and yesterday it was 92 and humid.
Minnesota: If you don't like the weather.. wait a minute.
S-Tank.. what a very peculiar tank, one of those, "In theory it looks great" and in reality.. Not so much.
Morning Gator Navy.
Sure is a low profile, I always figured is was closer to the German assault guns than a tank.
It would have been interesting to see how it stood up in combat with it's contemporaries. I figured it'd do ok from an ambush position getting in the first shot, like the German Sturmgeschutz and TD's.
Morning alfa6. [Didn't forget the 6 today ;-)]
Morning E.G.C. More rain again today, of course. It's the start of Rose Festival and tradition demands rain.
Morning GailA. What could be better? Your sweetrolls with Mayor's coffee right behind. :-)
Morning Mayor. Good coffee to wash down GailA's sweetrolls.
Happy Treadhead Tuesday, everyone! More or less back on my feet and happy to catch up on the Foxhole. Hope you are all well!
The British people know that, given strong leadership, time and a little bit of hope, the forces of good ultimately rally and triumph over evil. Here among you is the cradle of self-government, the Mother of Parliaments. Here is the enduring greatness of the British contribution to mankind, the great civilized ideas: individual liberty, representative government, and the rule of law under God.
I've often wondered about the shyness of some of us in the West about standing for these ideals that have done so much to ease the plight of man and the hardships of our imperfect world. This reluctance to use those vast resources at our command reminds me of the elderly lady whose home was bombed in the Blitz. As the rescuers moved about, they found a bottle of brandy she'd stored behind the staircase, which was all that was left standing. And since she was barely conscious, one of the workers pulled the cork to give her a taste of it. She came around immediately and said, ``Here now -- there now, put it back. That's for emergencies.''
Well, the emergency is upon us. Let us be shy no longer. Let us go to our strength. Let us offer hope. Let us tell the world that a new age is not only possible but probable.
During the dark days of the Second World War, when this island was incandescent with courage, Winston Churchill exclaimed about Britain's adversaries, ``What kind of a people do they think we are?'' Well, Britain's adversaries found out what extraordinary people the British are. But all the democracies paid a terrible price for allowing the dictators to underestimate us. We dare not make that mistake again. So, let us ask ourselves, ``What kind of people do we think we are?'' And let us answer, ``Free people, worthy of freedom and determined not only to remain so but to help others gain their freedom as well.''
Sir Winston led his people to great victory in war and then lost an election just as the fruits of victory were about to be enjoyed. But he left office honorably, and, as it turned out, temporarily, knowing that the liberty of his people was more important than the fate of any single leader. History recalls his greatness in ways no dictator will ever know. And he left us a message of hope for the future, as timely now as when he first uttered it, as opposition leader in the Commons nearly 27 years ago, when he said, ``When we look back on all the perils through which we have passed and at the mighty foes that we have laid low and all the dark and deadly designs that we have frustrated, why should we fear for our future? We have,'' he said, ``come safely through the worst.''
Well, the task I've set forth will long outlive our own generation. But together, we too have come through the worst. Let us now begin a major effort to secure the best -- a crusade for freedom that will engage the faith and fortitude of the next generation. For the sake of peace and justice, let us move toward a world in which all people are at last free to determine their own destiny.
Good Morning PE.
A sad and yet proud Flag-o-gram this morning.
Good morning Feather. Nice to see you in armor today. :-)
BTW, folks Microsoft is going to release their June seciryt updates for Windows today. Be sure to download them when possible.
Yeah the hydraulic system was definately interesting but like Iris7 said, the concept is pretty much a German assault gun just "fancier".
Morning Johnny. Nice seeing #51 roll in.
IMHO just another attempt to get a cheaper vehicle to do a tanks job.
Been raining all morning. Thanks for the Windows update info.
The development line of the MB339 dates back to the 1950's. Design by Aeronautica Macchi (Aermacchi) in Italy of what would be the MB326 began in 1954, and the prototype was first flown on December 10, 1957. The first production model of this classic trainer flew on October 5, 1960. The type was subsequently developed for the light strike role, culminating in the MB326-K single seat close support version which first flew on August 22, 1970. Along the way engine upgrades moved from the 794kg (1,750lb) RR Viper 8 to the 1,814 (4,000lb) Viper 632. Variants of the MB326 were used by Italy, Argentina, Australia, Brazil, Dubai, Ghana, South Africa, Togo, Tunisia, Zaire, and Zambia. The aircraft was license built in Australia (MB326H), Brazil (AT-26 Xavante), and South Africa (Impala).
By the 1970's consideration was being given to a successor to the MB326 and the Fiat G91 which was of similar vintage. Aermacchi was granted a study contract by the Italian Air Force in 1972. The result was the MB338 which had a number of proposed variants based on differing powerplants. Analysis reduced the options, and the Viper 632 powered MB339 was the successful candidate. The airframe shares much of its structure with the MB326-K, with the forward fuselage redesigned to allow the tandem seating to be staggered vertically (allowing the instructor to see over the pupil). The result was a stronger aircraft with a known airframe and an uprated powerplant compared to the MB326. Six hardpoints (up to 1,815kg/4,000lb) allow a combined trainer/light strike role. The first of two prototype MB339-X, (I-NOVE) was flown on August 12, 1976. The first production MB339-A were delivered to the Italian Air Force on August 9, 1979. Other customers include Argentina, Dubai, Ghana, Malaysia, Nigeria, and Peru.
Development of the MB339 has included the MB339-RM calibration model, and the MB339-PAN used by the Frecce Tricolori. The Viper 680 powered MB339-B is enhanced for the ground attack role. Similarly engined is the MB339-K (also known as the Veltro II), a single seat attack version (conceived in the same mould as the MB326K), which first flew on May 30, 1980. The latest production version is the MB339-C. This 1,995kg (4,400lb) Viper 680 powered model first flew on December 17, 1985. The first production customer was the RNZAF, who decided on the MB339-CB in March,1990.
The 'Macchi' served with the RNZAF from 1991 to 2001. Eighteen aircraft (NZ6460-NZ6477) were purchased to replace the BAC Strikemaster Mk88 which had been acquired in 1970, and was experiencing fatigue problems. The choice of the aircraft has been the subject of some controversy. Purchased at a time when the Defence budget was under pressure, the acquisition was closely monitored, and a number of alternatives (including the Pilatus PC-9, Alpha Jet,and Bae Hawk) were considered before the NZ$266 million deal was settled. 'Project Falcon' as the acquisition process was known was subject to the approval of eight committees before the contract was signed in March 1990. The first three aircraft were handed over on April 19, 1991. Further groups of three aircraft arrived at six month intervals. The first MB339 exercise was held in August 1991, and in October two aircraft were flown to Australia to participate in the RAAF 70th anniversary celebrations at RAAF Richmond (NZ6465 displayed). The first all MB339-CB training course was held in February 1992. The Strikemaster was retired on December 17, 1992.
As the first operator of the MB339 with the Viper 680-43 engine, the RNZAF has experienced a number of problems, which received a lot of media attention. Flameouts on wet runways, compressor stalls during rapid acceleration/deceleration, defective fuel supply components, turbine blade cracks, defective safety harnesses, and potential wiring problems lead up to a government decision in 1995 to withhold final payment for the aircraft pending resolution of the engine problems. The manufacturer subsequently agreed to meet the cost of the problem rectification, and the aircraft has settled into service. Subsequent reports indicated the RNZAF was more than happy with the aircraft.
Operated by 14 SQN based at RNZAF Ohakea, the aircraft provided the training step between the ab-initio CT-4E, and the operational A-4K. At the time of its acquisition all pilot trainees went through the jet conversion programme. In 1998 the RNZAF adopted a streamed training system, and only strike pilot candidates were sent for jet training. Flight training was supplemented by a one of a kind Macchi simulator designed and built by Hughes Rediffusion Simulation Ltd (now part of Thompson Training and Simulation Ltd). The aircraft also provided a second line strike capability, and combined state of the art avionics with the ability to carry most stores in the RNZAF inventory. Although capable of carrying a wide variety of weaponry, the aircraft were only cleared to carry 12.7mm gunpacks, BDU33 and BDU48 practice bombs, and CRV7 rockets in RNZAF service. The aircraft were normally operated only using four of the six hardpoints, and were commonly seen carrying two 325 litre auxillary fuel tanks (the fuselage tank holds 780 litre, and the tip tanks hold 1020 litres). Like the Strikemasters before them, the Macchis became a common sight as they deployed to annual 'Falcons Roost' exercises to various provincial airfields around the country. In 2000 as part of the Millenium celebrations, the RNZAF introduced a new formation aerobatics team. Named the Black Falcons, the team consists of instructors from 14 Squadron flying the MB339-CB. (illustrated below). The team performed in Auckland, Wanaka, and at the Ohakea Open day.
One aircraft was lost in service. NZ6465 crashed in the Awanui Estuary on the Rangaunu harbour near Kaitaia on October 13, 1993. PO C.J. Foster and LAC S.E. Gyde made a low level ejection after experiencing severe vibration and loss of thrust following foreign object injestion. This was the RNZAF's first non-aircrew ejection. Both ejected safely but sustained back injuries, landing in mangroves and mud. The aircraft was subsequently retrieved, and after being classified unrepairable was passed to the RNZAF museum. Several aircraft were been involved in landing incidents resulting in damage. NZ6467 being the first on on April 15, 1992 when the undercarriage was retracted at too low a speed during a touch and go at Ohakea, which resulted in a belly landing. NZ6460 was next when it made an emergency landing on its belly on November 28, 1994 after FOD ingestion resulted in an engine failure as the aircraft became airborne. The aircraft was returned to Italy for factory repair and after two years it was back in service in 1997. NZ6468 was the most recent on February 9, 2000. In other incidents, NZ6477 made an emergency landing at Hamilton in April 1999 after a birdstrike destroyed much of the canopy and damaged an ejection seat. Another incident occurred in June 1999 when 100 rounds of 12.7mm ammunition were accidental discharged from a gunpack on the ground at Ohakea, while an aircraft was being prepared for an exercise. The RNZAF investigation determined this result from a safety pin being inserted upside down - something not previously thought possible, and requiring design changes to correct. NZ6463 made a precautionary landing at Hastings on Mar 26 2001. The aircraft had been 40nm south of Napier when low fuel was indicated. The aircraft returned to Ohakea the following day.
On May 8, 2001, as part of a Defence review, the NZ Government announced the axing of the RNZAF strike force - this being the A-4K Skyhawk equipt 2 and 75 Squadrons. Without the strike force there was no rationale to maintain a jet trainer, and it was announced that the Macchi would also be retired. The disbandment of 14 Squadron occured on December 13, 2001. The aircraft are currently in storage at Ohakea and it is expected they will be sold.
The aircraft identities are laid out below. The ID number is the RNZAF serial, the batch number identifies the aircraft's position in the lot sequence, the serial number gives the aircraft's position in the sequence of MB339 construction, and the manufacturer number identifies the aircraft's position within the entire Aermacchi construction sequence
Manufacturer: Aeronautica Macchi
Type: Trainer/Light attack
Power Plant: 1,995 kgp (4,400 lb st) Rolls Royce Viper 680-43
Span: 11.22m (36'11ft)
Length: 11.24m (36'10ft)
Weights: empty : 4,930kg (10,870lb) / max : 6,350kg (14,000lb)
Max speed: 960km/h (600mph)
Max climb: 8000ft/min (2438m/min)
Ceiling: 49,200ft (15,000m)
Range: 1170km (730miles)
Six under wing pylons with a max loading of 3960 lbs, including:
External Fuel tanks
But all the democracies paid a terrible price for allowing the dictators to underestimate us. We dare not make that mistake again.
Unfortunately we forgot...again. Until 9-11 woke us up.
This is a great photo of the Swedish S tank..or *Credit card tank: )
General Tal of Israel was inspired by Swedish S Tank's design....looking at Merkava....you can see the similarities.
Super Tank can do it all....well....just about : )
LOL. That's right you are tall. I remember our discussion on what it must have been like in all those ships as tall as you are. Sam hit his head more than once on the Tarawa and recently on the Blueblack. Taller than a tank, able to leap tall buildings... :-)
I would think armor would be the most important aspect in designing a tank, though speed and fire power are right up there with it.
Good morning/afternoon/evening...whichever it is for you. ;-)
Good afternoon Aeronaut.
Morning EGC, thanks for the reminder.
I love carbs!!! Mornin' Gail.
Thanks PE for our respectful flag-o-gram today.