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Monochromelody

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  1. Monochromelody

    Tank neutral steer capability

    Yes, Soviet tanks started to have dual-flow transmission after WWII, like Объект 770 heavy tank, Объект 906 amphibious tank and so on. The МТ-ЛБ transmission is similar to АТ-Л artillery tractor's transmission, which is also dual-flow transmission.
  2. Monochromelody

    Tank neutral steer capability

    The neutral steer, or pivot steer, means the tank drive one track forward while the other track backward, to perform a turn-on-spot. The very first tank with neutral steer, believe it or not, is the German A7V in WWI. Here is the transmission of A7V. The transmission incorporate two independent gearbox, each connected to a 100-hp engine. The gearbox use clash gears to select speed, and bevel gear to select forward or reverse. It's easy to perform a neutral steer. Those tanks with electric transmission(St.Chamond, Porsche Tiger, etc.) can easily perform neutral steer, for their twin driving electric motors can rotate in opposite direction. And tanks with twin driving hydraulic motors(Panzer IV mit Hydrostatischem Antrieb) can neutral steer in a similar manner. As mentioned above, the simplest way to neutral steer is to have seperated gearboxes or sub-transmissions driving both tracks. US airborne tank M551 Sherridan and Ukraine T-84 Oplot are modern approach of this manner. Althought they neutral steer with tracks driving in different speed, thus they cannot pivot steer precisely on the central spot. The neutral steer capability is more common on dual-flow transmission. A dual-flow transmission, or “双流传动” in Chinese, means the power flow from engine into the transmission splitted into driving power flow and steering power flow, then they join together with mesh gears or planetaries. Control these power flows allows the driver to change speed and steer left or right. The dual-flow principle itself came up even earlier than the tank. The 1899 Vedovelli Priestley electric taxi equipped with double differential steering system, is capable of neutral steering. And the first tank with dual-flow transmission is the Schneider-Renault SRB, then evolved into the Char B1 heavy tank. The Char B1 tank's dual-flow principle is quite simple. The power splitted into two: the driving power flow into gearbox and drive the main differential; the steering power flow into the appareil Naëder, a hydrostatic pump-motor assembly, can rotate on different speed and direction. Char B1 can use appareil Naëder to control its hull howitzer precisly, this principle inspired the Swedish Strv 103 tank. And the US M1 Abrams tanks use a HSU(Hydrostatic Steering Unit) based on the same principle of appareil Naëder. (To be continued)
  3. Monochromelody

    Documents for the Documents God

    Sad to find out there is little information about AMX M-4's ZF transmission. ZF's official website mentioned that they converted a Entwicklung-Series tank transmission to meet French 1000-hp AMX M-4 tank design. This ZF-type transmission was widely used among early post war French heavy tank programs.
  4. Monochromelody

    Name that AFV: The New Tank ID thread

    From a Japanese magazine PANZER screenshot, it says: This is a Type 61 tank with a sort of ad-hoc spaced armour, using for target practice in exercise. The armour plates surrounding the turret and side skirts make it looks like a WW2 German Panzer IV. The crew tried to pull out a practice round stucking in the side skirt, this round was fired from a recoilless rifle. According to the vegetation of the exercise range, the vehicle was painted in a 4-colour camouflage.
  5. Monochromelody

    Name that AFV: The New Tank ID thread

    I've heard that this Type 61 tank with appliqué spaced armour was used for anti-tank rifle grenade firing practice.
  6. Monochromelody

    French flair

    Could you please tell some detail about the development of AMX 10 series AFV? Thank you.
  7. Monochromelody

    Name that AFV: The New Tank ID thread

    According to Rolf Hilmes' KPz Leopard 1 1956-2003, p.43, In year 1983, the Bundeswehr send two Leopard 1 tanks for 120 mm cannon conversion: one Leopard 1 A5 with cast turret, one Leopard 1 A3 with welded turret. And in Tankograd No.5014, p.30, The conversion of normal Leopard 1 A5 also included the preparation for installation of a 120mm smoothbore cannon, though never realised in production models.
  8. Monochromelody

    Name that AFV: The New Tank ID thread

    Leopard 1 A5 with 120 mm smoothbore cannon
  9. Monochromelody

    [Question] About AMX 10 RC transmission

    According to the gear train schematic, AMX 10RC have a triple-differential steering mechanism. This is more common on British after-war period armoured vehicle but quite rare on a French AFV. It differs from a Merritt-Brown gearbox, for the ring gear and sun gear of the steering planetary both driven in the same direction. Designed in the 1970s, the transmission of AMX 10RC shares some similarity with the TN15 gearbox of Alvis Scorpion light tank(FV101). Both of them combine the forward-reverse selector with the input bevel gears. The gear shifting part use a set of constant mesh gears with synchronizer and planet gears to have different gear reduction ratio. In total it can provide 4 forward ranges, as well as 4 reverse ranges, having the same gear ratios. When the range set to 'neutral' position, a pivot steer would be made. A pair of hydraulic-actuated disc brake is used for steering, controlled by a pair of steering levers.
  10. Monochromelody

    [Question] About AMX 10 RC transmission

    Thanks a lot! It appears to be a triple-differential steering system.
  11. Monochromelody

    [Question] About AMX 10 RC transmission

    Yes, Chieftain tank has a single steering radius for every gear, while Leopard 1 would have two steering radius for every gear, 4×2=8. And Ariete tank have 4×3=12 steering radius in total. The British prefer triple differential system for it's easier to produce and maintain, and a braking drum could probably be cheaper than a multidisc clutch.
  12. Monochromelody

    [Question] About AMX 10 RC transmission

    As far as I know, double-differential system split and transfer steering power flow by engaging different clutch(direction clutch, sometimes radius clutch), or brake certain steering planetary gear, or simply by a hydraulic pump-motor unit. Triple-differential system split steering power flow by braking either side steering planetary gear(usually sun gear), transfer steering power flow to the other side via a differential. It's much easier for a double-differential system to achieve different steering radius. For example, Single radius: Somua steering system(Somua S35), 5SD-200D(AMX 30B), CD-500(M41 Walker Bulldog), MT75(Japan Type 74) Double radius: Maybach Argus(Tiger I), ZF 4HP250(Leopard 1) Triple radius: ZF LSG3000(K1 MBT, C1 Ariete, EE-T1 Osório) Step-less steering: Naëder system(Char B1), FBTV-2B(Strv 103), SLM system(Panzer 68), HSWL 123(KJPz 4-5), HSWL 194(Marder IFV), HSWL 354(Leopard 2), S6-80(SK105), X1100(M1), TN54(Challenger 1) All these are double-differential system. Triple-differential system usually have single radius, like CD-850 series(M46 to M60), TN12(Chieftain)
  13. As we know, AMX 10 RC is a very special wheeled AFV for it's skid steering system. It can perform neutral steer, a.k.a. pivot steer or steer in place. The transmission case is similar to some tank transmission. The driver uses steering levers instead of a steerig wheel, and it's almost identical with those on AMX 10P tracked AFV. ↑wheeled AMX 10 RC ↓tracked AMX 10 P It even had a variant running on tracks: As for steering principle, there are different descriptions. Some info says AMX 10 RC use a triple-differential system, like some British tanks and AFVs. A similar skid-steering wheeled vehicle, TV1000 "Rhino" also use steering levers instead of steering wheel, and it have triple-differential system. When I looked for historical information, I found that French invented the first double-differential steering system for wheeled vehicle since 1898. And French tanks used double differential system since 1920s: Renault NC: "Cletrac" type double differential, or controlled differential. First tank using Cletrac system. Single radius. Char B1: "Naëder" type double differential, steering control via steering wheel connected to appareil Naëder(Naëder device). First production tank with hydrostatic steering mechanism. Step-less steering. Pivot steer. Somua S35: "Somua" type double differential, steering control via steering wheel connected to mechanical steering clutch. Single radius. Pivot steer. ARL 44: "ZF" type double differential, steering control via steering wheel. According to the document Notice du Char de transition, it can perform double radius steering and pivot steer. Char Lorraine 40t: "ZF" type double differential. Detail unknown. Double radius. Pivot steer. Char AMX 50: "ZF" type double differential. Detail unknown. Double radius. Pivot steer. AMX 13: "Cletrac" type double differential, or controlled differential. A more compact design, steering mechanism integrated with gearbox. Single radius. AMX 30: "Cletrac" type (1961 prototype or before), single radius; "Somua" type variant (early version AMX 30B, 5SD-200D), single radius, pivot steer; hydrostatic double-differential (AMX 30B2 upgrade, ENC-200), step-less steering, pivot steer. There's no clear evidence that French could gave up their experience on double-differential mechanism and turned to British triple-differential. I tried to look for AMX 10RC operator's handbook, but only gunnery handbook found on the internet. Any further detail information about AMX 10RC transmission would be appreciated.
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