The Flugabwehrkanonenpanzer Gepard: The Bundeswehr's Potent SPAAG

      A West German crewman of a Flugabwehrkanonenpanzer Gepard (Anti-Aircraft Cannon Tank “Cheetah”), more commonly referred to as the Flakpanzer Gepard, shows off a section of linked 35mm ammunition for the Gepard's twin 35mm Oerlikon GDF automatic cannons. The advent of the jet aircraft in the ground attack role meant that existing self-propelled anti-aircraft guns (SPAAGs) which relied on visual (optical) sighting (also called “clear weather” systems) and manual fire controls were rapidly on the road to obsolescence. The deployment by the Soviet Union of the ZSU-23-4 “Shilka” (Zenitnaya Samokhodnaya Ustanovka; Anti-Aircraft Self-Propelled System) beginning in 1965 which featured the RPK-2 “Tobol” (NATO codename Gun Dish) radar linked to its four 23mm 2A7 autocannons was something that the West had to fear as no NATO country had anything comparable. The U.S. Army did have the T249 Vigilante, a radar-controlled 37mm six-barrel rotary cannon that was capable of spitting out 3,000 rounds per minute. Mounted on a modified M113 armored personnel carrier chassis, development of the T249 started in 1956, one year prior to the start of the ZSU-23-4 program. However, by 1962, the T249 was canceled in favor of the General Dynamics MIM-46 Mauler self-propelled anti-aircraft missile system. Meanwhile, Germany commenced work on the Flapanzer Gepard in 1963 with the first four prototypes being constructed in 1969. These prototypes tested both 30mm and 35mm automatic cannons and on June 25, 1970, it was decided that the Gepard was to utilize the 35mm Oerlikon GDF guns. A year later, a further twelve prototypes were built. The Gepard was not an inexpensive piece of equipment with one Gepard having three times the price of a single Leopard 1 main battle tank (MBT). On February 5, 1973, the approval of funds for the purchase of 420 examples was given and in September of 1973, Krauss-Maffei was contracted to construct and assemble the new SPAAG. The first Gepards entered Bundeswehr service beginning in December 1976.

     The chassis of the Gepard consists of a Leopard 1 MBT hull with only a minimal of design changes. The key changes included adding more batteries, slightly increasing the distance between the third and fourth road wheel, and adding a Daimler-Benz OM 314 4-cylinder auxiliary diesel engine into a compartment that originally housed ammunition for the Leopard 1's main gun. This auxiliary engine generates 66 kilowatts and provides power to two tandem Metadyn machines linked to a flywheel which controls the turret traverse and gun elevation drives, two 3-phase 380 Hertz generators that operate the ventilation, fire control, and radar systems, and a Model 300-A 28 volt DC generator for the Gepard's electrical system. 260 gallons of diesel fuel feed the engine and provides up to a maximum of 48 hours of continuous usage. The engine is the same as the Leopard 1, being a MTU built Model 838 10-cylinder multi-fuel engine that produces 819 horsepower which gives the Gepard a maximum speed of 40mph with an operational range of 340 miles. The chassis modifications were done by Krauss-Maffei and also Porsche.

     The twin 35mm Oerlikon GDF guns and the turret were designed by Oerlikon-Bührle with the guns having a muzzle velocity of 4,700 feet per second that give an effective range of 5,500 meters. Each gun is supplied with link belted ammunition with a mixture of 320 rounds of anti-aircraft ammunition and 20 rounds of armor-piercing ammunition for a total capacity of 680 rounds. The combined rate of fire for the guns is 1,100 rounds per minute. Maximum gun elevation is 85 degrees with the maximum gun depression being 10 degrees. Fitted to the back of the turret on a retractable arm is the search radar developed by Hollandse Signaalapparaten while fitted to the front of the turret is the tracking radar, designed by Siemens. The search radar operates in the S band and has a 9 mile range while the tracking radar operates in the Ku band and also has a 9 mile range. In addition, the Gepard is equipped with a laser rangefinder. This provides the Gepard with all-weather fire-control. For self-defense, eight smoke grenade launchers are fitted to the turret, four per side. For protection, the turret has approximately 40mm of armor while the hull has between 50mm to 70mm of frontal armor, 35mm of side armor, and 25mm of rear armor. The armor type is RHA (rolled homogeneous armor).

     Today, the Gepard has been replaced in Bundeswehr service by the missile-armed Wiesel 2 Ozelot (“Ocelot”) Leichtes Flugabwehrsystem (Light Anti-Aircraft System). Brazil, Jordan, and Romania are the only current operators of the Gepard with Qatar to be the fourth with 15 expected to be in service by 2022 for anti-drone duties.

     As a note, the MIM-46 Mauler mentioned above ended up canceled in 1965. During the time of the Gepard's development, the U.S. came up with the M163 Vulcan Air Defense System (VADS) which utilized the General Dynamics M61 20mm 6-barrel Vulcan rotary cannon linked to a simple AN/VPS-2 range finder radar and M61 optical lead-calculating sight. Usage of a night vision sight allowed the M163 to have day and night firing capability. It was to work in conjunction with the missile-armed M48 Chaparral and thus between the two, short to long range engagements of enemy aircraft could be conducted. The M163 used the M113 chassis while the M48 utilized the M730 chassis, the latter a heavily modified carrier variant of the M113. In 1977, the U.S. Army started the M247 Sergeant York DIVAD (Division Air Defense) SPAAG project. Built on a M48 Patton tank chassis, the M247 was developed by Ford Aerospace and consisted of twin 40mm Bofors L/70 cannons in turret which also contained the search radar and the Westinghouse AN/APG-66 tracking radar. The entire M247 program was riddled with problems, not the least of which the M247 was built using as much “off the shelf” components as possible. Other problems included an easily jammed electronic counter-countermeasures (ECCM suite), the inability of the M247 to keep pace with the M1 Abrams MBT, a turret which turned too slow to engage fast moving targets, a tracking radar which was incapable of detecting targets from ground clutter and had a slow reaction time, and huge cost overruns. After 50 vehicles were built, the entire project was canceled in August 1985. In the meantime, the U.S. Army kept on using the M163 and M48 Chaparral into the 1990s before the introduction of the M6 Linebacker and later, the M1097 Avenger.

Consolidated Liberator B Mk.VI "V-Victor": Accident Over Monfalcone

     British bomber crews, like their American counterparts, faced a multitude of dangers. Enemy fighters and fighter-bombers, anti-aircraft fire, and even mechanical issues all posed hazards. But another danger was “friendly fire” accidents and this photograph is evidence of that. On March 16, 1945, the Consolidated Liberator B Mk.VI (the British designation for the B-24H) “V-Victor” (code KK320) of No. 37 Squadron RAF (Royal Air Force) was part of a bombing raid on the ship and marshaling yards in Monfalcone, Italy. “V-Victor” was piloted by Squadron Leader Lionel C. Saxby while other members of the eleven man crew included Pilot Officer (P/O) G.T. Barker (navigator), K.H. Westrope (tail gunner), Wally Lewis (top turret gunner), and Cliff Hurst (radio operator). Included in the raid were bombers from No.70 Squadron RAF of which one of the aircraft was another Liberator B Mk.VI, “R-Roger”. Both squadrons were part of No.231 Wing RAF which itself was part of No. 205 Group RAF, flying out of Tortorella Airfield in Italy. As the bombers reached their targets over Monfalcone, at 12,000ft., they began to release their payloads that consisted of 1,000lb GP (General Purpose) bombs. It isn't exactly known if “R-Roger” or “V-Victor” drifted from formation but the pilot of “R-Roger” was not aware “V-Victor” was now almost directly underneath them.

     Two bombs from “R-Roger” struck “V-Victor”. The first bomb hit directly on the top turret, shattering it while crumpling the upper fuselage, and then passed through the fuselage, creating a significant tear in the aluminum skinning. Fortunately for Wally Lewis, he had not been manning the turret at the time but was actually struck by the bomb as it passed through the fuselage, the glancing blow enough to render him unconscious. Cliff Hurst, whose radio station was located near the turret, suffered numerous small injuries from the shards of metal that whipped through his compartment, helped by the buffeting winds howling through the shredded fuselage. The second bomb struck the port, inner engine, buckling the cowling to the point the winds ripped away several pieces. The bomb also skidded off the cowling and knocked the propeller off in addition to causing the engine to trail smoke. Immediately after the hits, “V-Victor” quickly lost altitude and entered into a dive. Some of the crew made ready to abandon the stricken plane but Squadron Leader Saxby was able to recover from the dive and piloted “V-Victor” back the 300 miles to Tortorella Airfield, landing the bomber without incident. The photograph shows “V-Victor” after landing, the crew and maintenance men examining the damage. Baxby can be seen in the fuselage gash while the navigator, P/O Barker, is looking over the wrecked turret from a hatch while a mechanic assesses the extent of the engine damage.

     Although the damage was significant, it wasn't too severe that it could not be repaired. However, “V-Victor” was written off on April 26, 1945. In part, the decision to not repair the Liberator could have been due to the fact that the squadron was relocating to Aqir, Palestine beginning on October 2, 1945 and not long after, in December 1945, moved to Shallufa, Egypt where No.37 Squadron was eventually stood down on March 31, 1946.

The British FV4401 Contentious: An Ambitious Airmobile Tank

     One of the more interesting post-World War Two tank designs was the British FV4401 Contentious. The intent of the FV4401 was to provide a light (up to 20-tons), easily transportable armored fighting vehicle (AFV) that could be air dropped and provide armored support for airborne and rapid deployment forces. There were two designs put forward under the FV4401 designation. The first was a one man, thinly armored vehicle fitted with two 120mm L6 WOMBAT recoilless rifles, the latter being used due to their light weight. Each L6 was equipped with a autoloader fed from a seven-round rotary magazine. This first design was more of a tank destroyer, akin to the Japanese Type 60 tank destroyer developed from 1956 to 1960. The second design is the focus here. 

     Work commenced on the two-man FV4401 (sometimes called the Contentious II) in the mid-1950s and the design had a number of novel features. For armament, the Ordnance QF 20-pounder (84mm) gun was initially selected as, at the time, it was a excellent gun and was also used in the British Centurion main battle tank (MBT). Rather than put the gun in a true turret from the outset, the gun was fitted into the hull of the prototype in a very limited traverse mounting. This kept the height of the FV4401 low and also saved weight. The gun was provided with an autoloader which could effectively fire twelve rounds per minute. To elevate and depress the gun, the FV4401 was fitted with suspension that could be raised and lowered and to provide additional traverse, the tank was turned in place. To speed aiming, the gun had an optical light pulse sight which was tied into a servo that allowed for automatic adjustment of the gun and monitored the alignment of the gun as a whole. This was akin to an early implementation of a Movement Reporting System (MRS). Both the commander and the gunner had complete driving and gunnery controls. For armor protection, the front glacis was to feature horizontal rows of metal ridges. The purpose was to break up incoming projectiles before they struck the armor proper. Behind this was a four foot empty space that was filled with diesel fuel. When full, the fuel provided the equivalent of twenty-four inches of armor and behind that was a 40mm thick back plate which separated the fuel compartment from the crew compartment. Components for the initial prototype, namely the lower chassis, were taken from a British FV4101 Charioteer medium tank, the road wheels from the FV300 series (a project for lightweight armored fighting vehicles), and for an engine, a Rolls-Royce B Range diesel engine was used. This engine series, topping out at 187 horsepower for the B81 model (as used in the FV430 AFV series), wasn't to be the final engine fit as the Contentious II was to use an engine developing between 300 to 500 horsepower. The FV4401 was envisioned that at the sacrifice of added weight, a turret could be fitted as well as be fully Nuclear, Biological, and Chemical (NBC) sealed. The proposed turret was to be low in profile so as not to add significant height to the Contentious II.

     Sometime in the late 1950s, the FV4401 Contentious II prototype was completed. It was far more of a test vehicle for the adjustable suspension, gun mounting, and fire controls as the prototype was unarmored and the fuel tanks were situated outside the tank, secured to the track guards. The armor concept had been tested and showed that ignition of the diesel fuel following penetration did not occur. If a fire was started, the crew compartment offered some protection and it was planned to house the fuel within the space in armored tanks which would be able to contain any explosion. The explosion risk came more from the tank being penetrated when the fuel level was low and fumes were more in abundance within. To minimize fuel loss, the fuel in the front part of the hull were to be inside compartmentalized tanks. This novel armor, however, was not fitted to the prototype but would have had the Contentious II program continued and more refined prototypes produced. The 20-pounder gun was sighted to 2,000 yards and at that range, the Armor-Piercing Discarding Sabot (APDS) ammunition could penetrate 290mm of rolled homogeneous armor and at 1,000 yards, it could punch through 330mm of armor. This was more than enough to deal with two of the most common Soviet tanks, the T-54 and T-55. Ranging was accomplished by a pulse radar (seen here on the bracket above the gun). Despite the good performance of the 20-pounder gun, work was done on up-gunning the Contentious II with either a 120mm gun, a 155mm gun, or even a larger caliber gun.

     As for being air dropped, tests were done using steel constructed replicas in the general shape of the turreted Contentious II design starting in November 1956. They were deployed from a Blackburn Beverley heavy transport, the replicas fitted directly with skids and air bags as a form of impact cushioning. However, these tests were not overly successful, the steel showing significant damage from the landing forces despite the parachute braking and air bags. At least one of the damaged replicas ended up as a range target after impacting the ground, the test personnel seeing no worthwhile reason to recover it.

     The FV4401 Contentious II prototype was also tested at Lulworth Range in Dorset, England, against a 6X6 vehicle, the TV1000 Rhino, which was envisioned in a similar role as the FV4401 but using wheels. The TV1000 had stability problems, the rubber on the wheels wore out at an alarming rate, and the TV1000 used skid steering, much like a tank does, and thus offered little over the FV4401 which was deemed superior. 

     Despite the novel features and relative success during testing, the FV4401 was not put into production nor were further prototypes completed (some sources say at least two more were built) in the FV4401's final form. Had the FV4401 entered service, it would have given British airborne forces a significantly more advanced weapon in comparison to the U.S. M56 Scorpion which entered service in 1957 and would have also been superior to the Soviet ASU-57 airborne assault gun that began service in 1951.

     Today, the prototype shown in the photograph at Kirkcudbright Training Area survives to this day, able to be seen at the Tank Museum at Bovington in Dorset, England. Unlike the photograph, the FV4401 at Bovington is armed with a Royal Ordnance L7 105mm gun which was added for display purposes.

Northrop P-61B-1 "The Spook": 548th. Night Fighter Squadron

(U.S. Army Signal Corps)

     On April 20, 1945, the Northrop P-61B-1 Black Widow (serial number 42-39405) named “The Spook” was returning to Central Field located on Iwo Jima following a night patrol. Aboard was pilot Lieutenant Melvin Bode, radar operator Lieutenant Avery J. Miller, and gunner Staff Sergeant John Hope. “The Spook” was part of the 548th. Night Fighter Squadron (NFS), 7th. Air Force and tasked with performing combat air patrols and nocturnal escort operations for the Boeing B-29 Superfortresses of the 20th. Air Force flying out of both Saipan and Iwo Jima. Heavy fog obscured the landing field and so Lt. Bode decided to make a blind landing with the assistance of the airfield's AN/MPN-1 unit. The AN/MPN-1 (Mobile, Pulsed, Navigation aid) consisted of a 2 ½-ton 6x6 truck that mounted two PE-127 power units, an air conditioning unit, and spare parts for the radar trailer it towed. The trailer contained a radar set that provided range and azimuth data out to 30 miles and up to 4,000 feet in ceiling. In addition to the radar, the trailer housed HF (High Frequency) and VHF (Very High Frequency) communication to aircraft via a SCR-274 transmitter and BC-342 receiver. The operator, who had a booth inside the trailer, provided guidance to the pilot based on the radar readings. Unfortunately, “The Spook” was caught by a strong cross wind during the landing, causing the plane to drift. It clipped a parked P-61B (“Anonymous III”) before belly landing off the main runway. No injuries were sustained but it was the last flight for “The Spook” as the damage was too extensive to repair and so the aircraft was written off. The last entry known for “The Spook” was on June 6, 1949 where the aircraft was checked into Clark Field in the Philippines for reclamation (ergo, scrapping).

     The 548th. NFS was a fairly short lived unit. Activated on April 10, 1944, the unit deployed to Central Field, Iwo Jima in late January 1945 following months of training, patrol missions around Hawaii, and having to wait for their P-61 aircraft to be modified for operations in the Pacific Theater. Arriving at Central Field by the close of February 1945, the unit commenced long range patrols over the ocean. On several occasions, aircraft of the 548th. NFS encountered Imperial Japanese Air Force (IJA) Mitsubishi G4M bombers that more often than not, upon seeing the P-61s, jettisoned their payload and retreated. While this did not make for many kill scores for the unit, they were a deterrent which protected the airfields from attack. On June 13, 1945, the unit relocated to Ie Shima island near Okinawa and conducted nocturnal patrols over the Okinawa area and towards the end of the war, shifted to nocturnal intruder raids and conducting weather observations for B-29 bombers raiding the Japanese home islands. When the war ended, the ground personnel were reassigned to the Army of Occupation in September 1945 while the unit's aircraft were put into storage in Okinawa and Clark Field in the Philippines. All told, the 548th. NFS downed five enemy aircraft: three Mitsubishi G4M bombers, one Nakajima Ki-44 fighter, and one Nakajima A6M2-N floatplane. On December 19, 1945, the unit was inactivated. The unit was revived again as the 548th. Special Operations Training Squadron from October 15, 1969 to July 31, 1973 where the unit training pilots and crews of the Republic of Vietnam Air Force in how to fly and operate the Douglas C-47 Skytrooper, AC-47 Spooky gunship, and to a lesser extent, the EC-47 Phyllis Ann electronic warfare aircraft. For a third time, the unit was revived, this time as the 548th. Combat Training Squadron on July 1, 1994 and it remains active to this day out of Barksdale Air Force Base in Louisiana with a detachment based at Fort Polk, Louisiana.

     As for the P-61, it was the only “built from the ground up” night fighter deployed by the Allies during World War Two. It was powered by two Pratt & Whitney R-2800 Double Wasp 18-cylinder, air-cooled, radial piston engines that drove 4-bladed Curtiss Electric constant-speed propellers. These engines gave the P-61 a top speed of 366mph at 20,000 feet. Armament consisted of four 20mm AN/M2 Hispano cannons in a ventral tray with 200 rounds per gun and four .50 caliber M2 Browning machine-guns in a remotely operated, 360 degree traverse upper turret with each gun provided with 560 rounds of ammunition. For ground attack, the P-61 could carry up to four bombs up to 1,600 pounds each or six 5” HVAR (High Velocity Aircraft Rocket) unguided rockets. Avionics included the SCR-720 search radar and the SCR-695 tail warning radar. A total of 706 examples of the P-61 were built and the type was retired from service in 1954. Only four aircraft are known to exist today and includes a P-61C-1 (serial number 43-8353) on display at the National Museum of the U.S. Air Force at Wright-Patterson Air Force Base in Dayton, Ohio. It is painted in the livery of “Moonlight Serenade”, a P-61B-1 that was operated by the 550th. NFS.

     Finally, as a side, the coloration of “The Spook” was all black with red propeller spinners and cowl flaps with the propeller tips in yellow. The underside of the nose had a smiling pair of lips in red with white teeth, a white eye with a black dot and green iris with a gray bottom eyelid on either side of the nose and on the front, a white outline of a stylized human nose. The name of the aircraft consisted of “The” in white cursive with “Spook” in white with both of the “o” in the name being angry eyes with gray irises inside each “o”.

 

Northrop P-61A-1 "Nightie Mission": 6th. Night Fighter Squadron

(U.S. Army Signal Corps)

     The Northrop P-61 Black Widow was the first dedicated night fighter to be built and deployed by the U.S. Army Air Force (USAAF). It was also the first fighter to be designed with internally mounted radar equipment. Heavily armed with four forward firing Hispano M2 20mm cannons in the fuselage and a dorsal turret equipped with four Browning M2 .50cal. machine-guns, the P-61 saw service in all theaters in World War Two. 

     This photograph depicts “Nightie Mission”, a P-61A-1-NO belonging to the 6th. Night Fighter Squadron (NFS), being serviced in preparation for a mission. Sent to the Pacific Theater, the 6th. NFS operated from Saipan with the first sortie being flown on June 25, 1944. The primary mission of the 6th. NFS was to defend the Saipan airfields from Japanese attack given that Boeing B-29 Superfortresses were using Saipan as a launch point for attacks against the Japanese main islands. The 6th. NFS had a long history, being activated in 1917 then stood down in 1947. However, in 2017, the unit was reactivated as the 6th. Weapons Squadron and will be equipped with the Lockheed-Martin F-35A Lightening II for the purposes of generating weapons instruction material for pilot training. 

     Returning to “Nightie Mission”, pilot 1LT Francis “Lil Ab” Eaton, Radar Operator 2LT James “Chief” Ketchum, and gunner S/Sgt. William Anderson, III claimed a kill of a Mitsubishi G4M “Betty” bomber on July 7, 1944. This would be the only kill “Nightie Mission” was to achieve. The aircraft was written off on August 5, 1945 due to extensive damage caused on the ground by a typhoon.