Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!sdd.hp.com!elroy.jpl.nasa.gov!lll-winken!sun-barr!newstop!sun!amdcad!amdcad!military From: bxr307@coombs.anu.edu.au (Brian Ross) Newsgroups: sci.military Subject: Re: New Soviet Tanks Message-ID: <1991May14.051547.6785@amd.com> Date: 11 May 91 05:00:14 GMT References: <1991May9.063827.12230@amd.com> Sender: military@amd.com Organization: Computer Services Centre, Australian National University Lines: 87 Approved: military@amd.com From: bxr307@coombs.anu.edu.au (Brian Ross) Eric_S_Klien@cup.portal.com writes: >What is an elevated gun vehicle and what is the U.S.'s progress on >building one? An "elevated gun vehicle" is where the gun is mounted externally to the vehicle, above the turret or hull and is basically designed to be poked over things to enable the tank to assume a completely turret down positionwith nothing showing except the very small frontage area of the gun itself. This has the obvious advantage of that it makes a firing vehicle a much, much smaller target. It is also able to make full use of concealment and be much harder to spot. Tanks already attempt this when they assume hull down positions on the reverse slopes of hills with only their turret showing. Even so the advantages offered by only actually exposing the gun, rather than the whole turret are considerably. The potential target offered to the enemy is about 1/4 or less with an elevated gun vehicle, compared to the normal turreted vehicle. The problems being encountered in the West with developing such a vehicle concept is not so much in actually building a tank with a gun elevated above the hull but rather with the associated fire control systems and optics. The biggest problem thus far encountered is the considerably decreased field of view which the commander is provided with when he has to rely upon an indirect optronic system for observation of the surrounding countryside. As I am sure the ex-tank commanders who post here would confirm, one of the best things a tank commander can do, if he's brave enough is operate with his head out of his turret. It ensures that he has a much better field of view than relying upon his cupola, and can detect threats much more quickly. If the commander is forced to rely on an optronic system for his vision, then he has to act much more cautiously and has much greater difficulty scanning the surrounding terrain for potential dangers. Also in a conventional tank turret, if all the expensive machinery is knocked out, its still possible for a tank commander to control his own little bit of the battle by poking his head out occassionally, whereas if he is buried in the hull of the tank, below the level of the gun (which is how most of these elevated gun vehicles place him for added protection), he has to expose much more of himself in order to be able to adequately survey the surrounding terrain. The same goes for the reloading of the gun. While its now relatively easy to overcome the technical problems emplied in having to resort to a mechanical loader, the tank crew can still act as a last resort manual backup system if it fails, as they are inside the turret with the gun. If the weapon is mounted above the tank, or the crew are physically isolated from it (some of these proposals have a "stub-turret" where the gun is surrounded by the absolute minimum of turret in an effort to reduce its frontal area) they cannot reload the gun. Instead they are forced to withdraw from the battle and have it repaired. The final major problem, which is related to that of the commander, is the gunner's. He is also expected to be able to operate the gun, while physically isolated from it. While its less of the problem for him, the use of a pure optronic system, and being removed from the rotating mass of the turret could lead to disorientation. In otherwords he might think the gun is pointing somewhere else, when in fact its not. This sort of problem is lessened when he's actually in the turret and rotates with the gun. A similar problem was encountered when developing the MBT-70 (the failed predecessor to the M1 and Leopard 2). It had the driver in the turret, physically isolated from the rest of the crew in a rotating "drum" cupola which was designed to counter-rotate and keep him facing forward when the turret rotated. It was fine in theory and usually worked in practice, however it was found that too often the driver became disoriented as the turret traversed around him (the driver was subconsiosely relying upon visual cues in his field of vision, such as the corners of the turret and so on to keep himself oriented as to where the tank was going and what it was doing. However these visual cues kept changing while the vehicle was even moving in a straight line. While it was possible for a driver to be trained to overcome this it was felt to be too time consuming). Before its cancellation the MBT-70 was undergoing a redesign to eliminate the "driver in a turret" concept and return him to his proper place at the front of the hull. -- Brian Ross