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
are acknowledged, affirmed and commemorated.
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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.
I hope that we can in the future, become freinds, for real, again, and for the first time!
I apologize for past transgressions.
It's a light screen that can be extended so that the tank can "float" across rivers. I'm sure it's based on the DD tanks from D-Day. You would try to avoid using it while under enemy fire.
Evening Diva Betsy Ross. Thanks for dropping by.
We've had some differences of opinion in the past. There were no transgressions to apologize for. You're welcome anytime.
Of course! I knew that . . . ;^)
Hiya Radix. Good to see you. I hope you and yours are well.
He's sooooo cute, can I have him? What name does he or she have?
LOL. I see Obe-one has responded. :-)
Nice bike, thanks Betsy.
I have never before today posted in the Foxhole.
Ha, it doesn't hurt.
It can only get better from here, in my view.
Again, I apologize for my past transrgressions in other forums!
Your welcome anytime. You know the mission here, it's at the start of every thread. There isn't enough history being taught and we hope we are telling the stories well.
Jump in anytime.
The mission is bigger than all of us and what is most important. ;-)
Of course, You learned about them on Snippy's "Funnies" thread. :-)
I have never before today posted in the Foxhole.
Did anyone tell you about the $20.00 fee that first time posters pay me?
LOL! Now why didn't Snippy and I think of that.
Good Night w_over_w.
Snippy is always around here somewhere. :-)
Hey I'm a republican, and only in it for the money. :-)
Time for bed.
Oh, one of those evil corporate types huh? Night Valin.
I'm never too far away. Good night w over w.
Cuz' we'd be all alone here.