rp sergeant york v2

8/4/2019 RP Sergeant York V2

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An Ineffective System: The M247 Sergeant York

Russell Phillips

Copyright 2011 Russell Phillips

Also by Russell Phillips:

Weapons & Equipment of the U.S. Army

Cover photograph by Flickr user "Tumbleweed:-)", released under aCreative Commonsatrribution licence
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An Ineffective System: The M247 Sergeant York

Background

In the late 1960's, helicopters with anti-tank missiles started to be deployed, and a new tacticknown as a "pop-up" was developed. The helicopter would hover behind cover, then climb

just high enough to fire a missile, before dropping down behind cover again. Newer missilessuch as the American TOW allowed the helicopter to perform such a manoeuvre quickly,limiting it's exposure to enemy fire. By 1977, the Soviets had introduced the 9K114 Shturmmissile (known to NATO as the AT-6 Spiral), which had a range of 5km.

The U.S. army's anti-aircraft systems at this time were the Vulcan, which had a maximumrange of only 1,200 metres, and the Chaparral, which couldn't lock on to the helicopter beforeit dropped back down behind cover. As if to add insult to injury, the Soviets introduced theZSU-23-4 Shilka, which was able to engage U.S. helicopters performing pop-up manoeuvres,even while the U.S. army had nothing capable of doing the same. The ZSU-23-4 proved to beeffective during 1973 Middle East War, and in 1974 the army concluded a "Gun Air DefenseEffectiveness Study". As a result of this, two companies were given development contracts,but no vehicles were put into production because the 25mm guns that they used hadinsufficient range and didnt use NATO standard ammunition.

Requirement

The U.S. army issued the "Advanced Radar-directed Gun Air Defense System" (ARGADS)requirement, which was later renamed "Divisional Air Defense" (DIVAD). Unusually, therequirement specified that the system was to use existing parts. This was done in an attempt

to cut down on development time, since the problem was considered to be extremely seriousand a solution was urgently required. It was believed that this approach would cutdevelopment time by anything up to five years.

The requirement was for a vehicle based on an M48 tank chassis provided by the army (therewere many spare M48s in depots which could be used for this purpose). It was to be armedwith a gun of 30-40mm calibre, capable of engaging a target within 5 seconds of it cominginto range, with a 50% chance of hitting the target with a 30 round burst. It was to have all-weather capability and an optical aiming system equipped with forward looking infra-red(FLIR) and a laser range finder. The five second engagement time was later relaxed to eightseconds.

Entries

There were several entries for the competition. Sperry Rand's entry used their Vigilante gunfiring 35mm Oerlikon ammunition, as used by several other NATO countries. The gun wasfed from a magazine holding 1,464 rounds and was mounted in an aluminium turret. Tworadars and an IFF system were mounted on top of the turret.

The entry from General Electric used the 30mm GAU-8 Avenger seven-barrel rotary cannon(the same cannon fitted to the A-10 Thunderbolt II aircraft). It had a single radar for bothsearch and tracking, based on the AN/MPQ-49 Forward Area Alerting Radar.

Raytheon entered a system using the turret from the German Gepard anti-aircraft tank. It


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retained the same twin 35mm Oerlikon KDA cannons as the Gepard, but had a Hollandseradar and an Oerlikon Contraves fire-control computer. Despite being designed to be fitted toa Leopard I, Raytheon demonstrated that the turret could be fitted to an M48 with somemodification.

The General Dynamics entryused the same twin cannons asthe Raytheon, but mounted themside by side in the middle of anew aluminium turret. They werefed from 600 round magazinesand could achieve a combinedrate of fire of 1,100 rounds perminute. Radar and fire controlwere based on the systems usedon the Phalanx ship-board CIWS

(close-in weapons system). Thesearch radar was mounted on topof the turret, with the trackingradar next to the guns.

Ford Aerospace entered a systemusing two Bofors 40mm L/70cannons, mounted in the middleof the turret. Two radars (one search, one tracking) were mounted on booms on top of theturret, allowing them to be folded down for travel. The tracking radar was based on theWestinghouse AN/APG-66 , as fitted to the F-16 fighter. The turret's armour was proofagainst small arms fire and artillery splinters, and the vehicle had NBC protection for thecrew.

The choice of a 40mm gun in the Ford design was the subject of some controversy. Somemaintained that Ford chose it because they had a marketing agreement with Bofors, and couldtherefore make more profit from Bofors guns. On the other hand, FACC had developed a40mm round with a proximity fuse, and the larger round meant a greater quantity of highexplosive. These both led to a higher probability of a kill.

In early 1978, General Dynamics and Ford were given $79 million contracts to produce

prototypes, designated the XM246 and XM247 respectively. In 1980, each companydelivered two prototypes for testing at Fort Bliss. The tests lasted five months, and it was saidthat the General Dynamics vehicle had out performed the Ford vehicle consistently in thetests, but the Ford was controversially chosen as the winner in 1981 (there were accusationsthat the Ford was only chosen due to intense lobbying). Ford were given a fixed-pricecontract for the completion of development and the initial production run. The vehicle wasofficially designated the M247 Sergeant York. The contract included an option for the armyto buy up to 276 vehicles over three years, and it was expected that the army would buy atotal of 618 vehicles.

Problems

The M247 was very advanced. The fire-control system automatically handled all aspects ofevaluating threats, selecting ammunition and aiming, taking into account target speed and

General Dynamics XM246


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environmental factors. Manual overrides were included for all automatic systems. Theoperator's display showed the targets in priority order, and the operator simply had to selectwhich one should be targeted.

Problems became apparent almost immediately, particularly with the tracking radar. It had

difficulty differentiating between helicopters and trees, and when the guns were trained to ahigh degree of elevation, the barrels caused more difficulties for the radar. The specificationhad originally called for an engagement time of five seconds, and although this was increasedto eight seconds, the system still failed to meet this requirement. Against helicopters it onlymanaged 10-11 seconds, and against high-speed targets the engagement time was 11-19seconds.

As testing went on, moreproblems became apparent. Theelectronic counter-countermeasures suite was simplistic

and easily foiled, the turretsuffered from hydraulic leaks incold weather and couldn't turnquickly enough to track a fastmoving target. The guns weretaken from U.S. Army stock andwere found to have been storedbadly. Finally, the vehicle wastoo slow to keep pace with thenew M1 Abrams and M2/M3Bradley, which it was intendedto protect on the battlefield.

In a demonstration for officersand VIPs, the system locked onto the viewing stands, causing something of a minor panic asthe observers dived for cover. The technicians made several attempts to solve the problems,but the test system didn't manage to engage any targets. A Ford manager claimed theproblems were due to the vehicle having been washed for the demonstration, and that this hadaffected the electronics, causing a journalist to wonder sarcastically if it ever rained inCentral Europe. Problems continued to be evident as production started, one vehicle famouslylocking onto a latrine fan, mistaking it for a moving target.

Program Cancelled

The M247 was getting a lot of bad press and was unpopular in Washington, but the armypushed for it to be deployed, since there were no viable alternatives available. However, theSoviet Union was starting to deploy new, longer-ranged anti-tank missiles, which wouldallow their helicopters to stay at a range where the M247 would be much less effective. Thearmy suggested that Stinger surface-to-air missiles could be fitted to the M247 to counter thisproblem, but this simply fuelled complaints that the system was a waste of money.

Caspar Weinberger, the Secretary of Defense, ordered a series of battlefield condition tests,monitored by the new Operational Test and Evaluation Office (OT&E), which were carriedout in late 1984. The M247 did not perform well. Tests were continually relaxed - when thesystem failed to hit targets flying in a straight line, the targets hovered. When the radar

M247 Sergeant York


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couldn't lock on to the target, radar reflectors were added. Four reflectors were added beforethe radar was able to lock onto the target.

The OT&E concluded that the M247 did meet the requirements specified, but it had severereliability issues. The OT&E reported that "As tested, the Sergeant York was not

operationally effective in adequately protecting friendly forces during simulated combat,even though its inherent capabilities provided improvement over the current Vulcan gunsystem. The Sergeant York was not operationally suitable because of its low availabilityduring the tests." The requirement was for 90% availability, but the OT&E found it had anavailability of only 33%.

The program was cancelled in August 1985, after 50 vehicles had been built. Announcing thedecision, Caspar Weinberger noted that "A decision to cancel what is basically an ineffectivesystem doesn't eliminate the need", and so the army started to look for another system to fulfilthe requirement. They eventually settled on the M6 Linebacker, an M2 Bradley with Stingermissile launchers.

Technical Specification

Weight: 54.4 tonsLength: 7.67m (gun forward); 6.42m (hull only)Width: 3.63mHeight: 3.42mCrew: 3 (commander, gunner, driver)

Elevation: -5 to +85Traverse: 360

Rate of fire: 600 RPMMaximum range: 12.5 kmPrimary armament: 2 Bofors 40 mm L/70

Engine: Continental AVDS-1790-2D diesel, 750 HPOperational range: 300 miles (about 480 km)Road speed: 30 MPH (48 km/h)

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About the Author

Russell Phillips writes books and articles about military technology and history. His articleshave been published in Miniature Wargames, Wargames Illustrated and the Society of

Twentieth Century Wargamers Journal. Some of these articles are available on his web site.

Also by Russell Phillips:

Weapons & Equipment of the U.S. Army

Connect with Russell Phillips Online

Web site: www.russellphillipsbooks.co.ukTwitter: @avantman42Facebook: Russell PhillipsGoodreads: Russell Phillips

E-mail: [email protected]
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