Republic-Ford JB-2

The United States had known of the existence of a new German secret weapon since 22 August 1942 when a Danish naval officer discovered an early test version of the V-1 that had crashed on the island of Bornholm, in the Baltic Sea between Germany and Sweden, roughly 120 kilometers (75 miles) northeast of the V-1 test launch ramp at the Peenemünde Army Research Center, on Germany's Usedom Island. A photograph and a detailed sketch of the V-1 test unit, the Fieseler Fi 103 V83 (Versuchs-83, the eighty-third prototype airframe) was sent to Britain. This led to months of intelligence-gathering and intelligence-sifting which traced the weapon to the airfield at Peenemünde, on Germany's Baltic Coast, the top-secret German missile test and development site.[1]

As more intelligence data was obtained through aerial photography and sources inside Germany, the United States decided to develop a jet-powered flying bomb in 1943. The United States Army Air Forces gave Northrop Aircraft a contract in July 1944 to develop the JB-1 (Jet Bomb 1) turbojet-powered flying bomb under project MX-543. Northrop designed a flying-wing aircraft with two General Electric B1 turbojets in the center section, and two 900 kg (2000 lb) general-purpose bombs in enclosed "bomb containers" in the wing roots. To test the aerodynamics of the design, one JB-1 was completed as a manned unpowered glider, which was first flown in August 1944.[1]

In July 1944, three weeks after German V-1 "Buzz Bombs" first struck England on 12 and 13 June, American engineers at Wright Field fired a working copy of the German Argus As 014 pulse-jet engine, "reverse-engineered" from crashed German V-1s that were brought to the United States from England for analysis. The reverse engineering provided the design of America's first mass-produced guided missile, the JB-2.[2] The matter of guided missiles became a jurisdictional issue between Army ground Forces and the Army Air Forces. The dispute was decided in favor of the AAF as the JB-2 had wings and flew. It was decided that the JB-2 "should be placed in combat, needed or not, as an insurance measure for AAF claims.[3]

By 8 September, the first of thirteen complete JB-2s, reverse engineered from the material received at Wright Field in July was assembled at Republic Aviation. The United States JB-2 was different from the German V-1 only slightly in dimensions. The wing span was only 2½ inches wider and the length was extended less than 2 feet (0.61 m). The difference gave the JB-2 60.7 square feet of wing area versus 55 for the V-1.[1] One of the few visible differences between the JB-2 and the V-1 was the shape of the forward pulsejet support pylon — the original V-1 had its support pylon slightly swept back at nearly the same angle on both its leading and trailing edges, while the JB-2's pylon had a vertical leading edge and sharply swept-forward trailing edge. A similar, completely coincidental re-shaping, but with a much broader chord, was used for the same airframe component[4] of the manned Fieseler Fi 103R Reichenberg, original V-1 ordnance development. Initial testing of the first batch of prototype missle resulted in a decision to change from the preset guidance of the V-i to a command guidance system utilizing a radar beacon in the missile and radio command guidance from a tracking SCR 548 radar.[5] The indigenously-designed, unpowered U.S. Navy's Bat anti-ship glide bomb already had an active radar homing system in its nose to locate its intended maritime targets so an American innovation in guidance was an obvious improvement.

With its Ford-produced PJ31 pulsejet powerplant, the JB-2 was one of the first attempts at a powered cruise missile for potential usage in America's arsenal. The first launch of a JB-2 took place at Eglin Army Air Field in Florida by the 1st Proving Ground Group on 12 October 1944. In addition to the Eglin group, a detachment of the Special Weapons Branch, Wright Field, Ohio, arrived at Wendover Field, Utah, in 1944 with the mission of evaluating captured and experimental systems, including the JB-2. Testing was from a launch structure just south of Wendover's technical site. The launch area is visible in aerial imagery (40°41′53″N 114°02′29″W). Parts of crashed JB-2s are occasionally found by Wendover Airport personnel.[1]

In December 1944, the first JB-1 was ready for launch. The missile was launched by a rocket-propelled sled along a 150 m (500 ft) long track, but seconds after release the JB-1 pitched up into a stall and crashed. This was caused by an incorrectly calculated elevon setting for take-off, but the JB-1 program was subsequently stopped, mainly because the performance and reliability of the GE B1 turbojet engines were far below expectations. In addition, the cost to produce the Ford copy of the Argus pulse-jet engine of the JB-2 was much less than the GE turbojets. Subsequently, work proceeded on the JB-2 for final development and production.[1][6]

An initial production order was 1,000 units, with subsequent production of 1,000 per month. That figure was not anticipated to be attainable until April 1945. Republic had its production lines at capacity for producing P-47 Thunderbolts, so it sub-contracted airframe manufacturing to Willys-Overland. Ford Motor Co built the engine, initially designated IJ-15-1, which was a copy of the V-1's 900-lb. thrust Argus-Schmidt pulse-jet (the Argus As 014), later designated the PJ31. Guidance and flight controls were manufactured by Jack and Heintz Company of Cleveland, Ohio, and Monsanto took on the task of designing a better launching system, with Northrop supplying the launch sleds. Production delivery began in January 1945.[1]

At one point proponents envisioned 75,000 JB-2s planned for production. This was absurd as it would have competed with the established manned bomber forces for sealift from America to Europe. Commander of Strategic Air Forces in Europe, Spaatz proposed a much more limited role as a harassment weapon on days where weather limited bombers. Moreover the air forces only wanted the JB-2 if it caused no curtailment of the supply of bombs, artillery shells, and personnel being shipped to Europe.[7] A USAAF launching squadron was formed in anticipation for using the weapons both against Nazi Germany and Japan. However, the end of the European War in May 1945 meant a reduction of the number of JB-2s to be produced, but not the end of the program. Army commanders in Europe had dismissed it as a weapon against Nazi Germany, as the strategic bombing concept was implemented and by 1945 the number of strategic targets in Germany was becoming limited. However, the JB-2 was envisioned as a weapon to attack Japan. A 180-day massive bombardment of the Japanese Home Islands was being planned prior to the amphibious landing "by the most powerful and sustained pre-invasion bombardment of the war". Included in the assault were the usual naval bombardment and air strikes augmented by rocket-firing aircraft and JB-2s.[1]

A navalized version, designated KGW-1, was planned to be used against Japan from LSTs (Landing Ship, Tank) as well as escort carriers (CVEs). In addition, launches from PB4Y-2 Privateers were foreseen and techniques developed. As WWII ended in Europe the Army Air Forces had JB-2 crews on transports headed for use against Japan.[8] The war's end led to the cancellation of Operation Downfall and the production of JB-2s was terminated on 15 September. A total of 1,391 units were manufactured.[1]

Though production was halted in mid-September 1945 testing was continued with JB-2s already constructed.[9] Several launch platforms were developed, including permanent and portable ramps, and mobile launching from beneath the wings of Boeing B-17G or Boeing B-29 bombers, much as the Heinkel He 111H-22 had done late in the war for the Luftwaffe in offensive air-launches of V-1s against the Allies. Testing continued from 1944 to 1947 at Eglin to improve launch and guidance. Tests of the JB-2 were conducted by the 1st Experimental Guided Missiles Group. The testing was at Wendover Air Force Base, Utah and Eglin AFB, Florida. At Eglin the JB-2 was tested at three land sites at the Santa Rosa Island Range Complex as well as air launches flown from Hurlburt Field. In 1947 the USAF decided to move JB-2 testing to Alamogordo Air Force Base, New Mexico using the test range at White Sands.[10] When used to test launch methods the JB-2 was designated the LTV-A-1 (from "Launch test vehicle, Army") by the Air Force.[11]

The U.S. Navy's version, the KGW-1 was intended for installation on surface ships and shore installations.[12] In 1946 it was re-designated KUW as a test vehicle, then renamed LTV-N-2.[11] The first launch of a LTV-N-2 was from Point Mugu, California on January 7, 1946.[12] As KUW/LTV-N-2 and given the name of an aquatic bird the "Loon" it was developed to be carried on the aft deck of submarines in watertight containers. The submarine to carry the LTV-N-2 was USS Cusk (SS-348) which successfully launched its first Loon on 12 February 1947, off Point Mugu, CA. The USS Carbonero (SS-337) was modified to provide mid-course guidance for Loon.[12] The Navy program lasted until the last launch of a LTV-N-2 on September 11, 1953.[13] The LTV-N-2 program developed a number of launchers and varied launching techniques, variations in guidance, command guidance computers, the TROUNCE guidances system for SSM-N-8 Regulus, telemetry systems, flight termination, and tested a J30 turbojet as a power plant.[14]

After the United States Air Force became a fully independent arm of the National Military Establishment 18 September 1947, research continued with the development of unmanned aircraft and pilotless bombers, including the already available JB-2.

The USAF Air Materiel Command reactivated the JB-2 as Project EO-727-12 on 23 April 1948, at Holloman AFB, New Mexico. The JB-2 was used for development of missile guidance control and seeker systems, testing of telemetering and optical tracking facilities, and as a target for new surface-to-air and air-to-air missiles (fulfilling the V1's cover name, Flakzielgerät — anti-aircraft target device). The JB-2 project used the North American Aviation NATIV (North American Test Instrument Vehicle) Blockhouse and two launch ramps at Holloman: a 400 ft (120 m), two-rail ramp on a 3° earth-filled slope, and a 40 ft (12 m) trailer ramp.[15] The trailer ramp was the first step toward a system which would eventually be adapted for the forthcoming Martin MGM-1 Matador, the first operational surface-to-surface cruise missile built by the United States. The program at Holloman was terminated on 10 January 1949 after successful development of a radio guidance and control system that could control and even skid-land a JB-2 under the control of an airborne or ground transmitter.[1]

The 1st Experimental Guided Missiles Group used JB-2s in a series of tests in the late 1940s at Eglin Air Force Base, Florida. In early 1949, the 3200th Proof Test Group tested launching JB-2s from the under the wings of B-36 Peacemaker bombers at Eglin AFB.[16] About a year later, JB-2s were tested as aerial targets for experimental infrared gunsights at Eglin.[17]

The Navy version was featured in the movie The Flying Missile (1951), including submarine launches. The movie shows the missile being launched from a trolley with four JATO bottles.

In the mid-1992, military crews uncovered the well-preserved wreckage of a JB-2 at a site on an Air Force-owned section of Santa Rosa Island. Most crash sites on the barrier island were little more than flaky rust, but after the find, officials were planning further searches.[18]

Republic-Ford JB-2 at Keelser AFB, Biliox, Mississippi. May, 1961

JB-2 on display at the National Air and Space Museum, Steven F. Udvar-Hazy Center

JB-2 on display at the Cradle of Aviation Museum.

• A JB-2 is on display at the National Museum of the United States Air Force in Dayton, Ohio.[19]
• A JB-2 is on display at the Steven F. Udvar-Hazy Center of the National Air and Space Museum in Chantilly, Virginia.[20]
• A JB-2 is on display at the Cradle of Aviation Museum in Garden City, New York.[21][22]
• A JB-2 is on display at the Evergreen Aviation & Space Museum in McMinnville, Oregon.[23]
• A JB-2 is on display at the American Heritage Museum in Stow, Massachusetts. It is painted to resemble a V-1.[24]
• A JB-2 is on display at the Hill Aerospace Museum in Roy, Utah.[25]
• A JB-2 is on display at the White Sands Missile Range Museum near Las Cruces, New Mexico.[26]
• A JB-2 is in storage at the New England Air Museum in Windsor Locks, Connecticut.[27]
• A composite V-1/JB-2 is on display at the Cosmosphere in Hutchinson, Kansas. The missile is painted as a V-1, but is a composite of V-1 and JB-2 parts and has a JB-2 Loon-style forward engine support fairing.[28]
• A JB-2 is on display at the Air Force Museum of New Zealand in Christchurch, New Zealand. It was previously on display at the Museum of Transport and Technology.[29]
• A JB-2 is on display at the Air Force Armament Museum at Eglin Air Force Base near Valparaiso, Florida.
• A JB-2 is on display at the Museum of Alaska Transportation and Industry in Wasilla, Alaska.
• A JB-2 is on display at the Point Mugu Missile Park at Naval Air Station Point Mugu near Port Hueneme, California.
• A JB-2 is on display at the U.S. Army Artillery Museum at Fort Sill, Oklahoma.
• A JB-2 is on display at the Rocket Park at the U.S. Space & Rocket Center.
• A JB-2 is on display at the American Legion post in Wheaton, Minnesota.[30]

JB-2 Loon, Wheaton, Minnesota

• A JB-2 is on display at Milford Township Park at Milford, Illinois.[31]

Related development

• V-1 (flying bomb)

Aircraft of comparable role, configuration, and era

• Interstate XBDR
• McDonnell LBD Gargoyle

• 1st Experimental Guided Missiles Group

Launch locations

• Wendover Air Force Base, Utah JB-2 Testing Site (40°41′52″N 114°02′29″W)
• Holloman Air Force Base, New Mexico JB-2 Testing Site (32°53′33″N 106°07′24″W)
• Santa Rosa Island Range Complex, JB-2 Launch Sites 30°23′57″N 086°42′21″W (30°23′54″N 086°41′33″W)
• Wagner Field, Florida (Formerly: Eglin Air Force Auxiliary Field #1) (30°39′46″N 086°20′41″W)

 This article incorporates public domain material from the Air Force Historical Research Agency website http://www.afhra.af.mil/.

Wikimedia Commons has media related to Republic-Ford JB-2.

• Early History and Evolution of cruise missiles, JB-2 Loon development and testing, USAF 38th Tactical Missile Wing.
• JB Series (JB-1 through JB-10) Directory of U.S. Military Rockets and Missiles
• V-1 "Buzz Bomb"/JB-2 Flying Bomb Fact Sheet at Hill Air Force Base website
• Short JB-2 launch from a B-17 video clip
• JB-2 launches video
• Ford PJ31 pulsejet test run at the Planes of Fame museum