History of Rocketry Chapter 5
By Cliff Lethbridge
U.S. Army Supports JATO Rocket Tests
Static test firings of jet-assisted take-off (JATO) units developed with the support of the U.S. Army Air Corps began in May, 1940. The Army Air Corps had considered a number of solid-fueled and liquid-fueled JATO concepts prior to developing an actual engine.
It had been determined that liquid-fueled JATO units would be more powerful than solid-fueled JATO units, but an alternative fuel to liquid oxygen would need to be incorporated since liquid oxygen could not be transported or stored for long periods.
As a result, the JATO engines actually developed and tested burned red fuming nitric acid (RFNA), which could be stored for long periods of time, in combination with either gasoline or benzene.
The U.S. Bazooka
Although the U.S. was able to introduce a number of missiles during World War II, the best known and perhaps most popular remains the bazooka. The bazooka was a rocket-powered grenade, the design of which may be traced back to research Dr. Robert Goddard undertook for the U.S. Army during World War I.
The World War II version of the bazooka was designed under the direction of the Army Ordnance Department beginning in 1940. The first version of the bazooka introduced for wartime use was 2.36 inches in diameter and was about seven feet long. The rocket-powered grenade it launched was a modified mortar shell with added stabilization fins, exhaust nozzle and propellant tank.
The version of the bazooka most widely used during the war was 4.5 feet long and had a diameter of three inches. The unit weighed just 13.3 pounds, and launched a rocket grenade that was 2.36 inches in diameter and 1.8 feet long. The projectile weighed just 3.4 pounds, of which 1.57 pounds was made up of an explosive charge. The projectile was launched by a squib-type igniter.
The bazooka was able to disable a moving tank from distances of up to 200 yards. At distances of up to 700 yards, the bazooka could knock out bunkers and stationary targets. The U.S. Army considered that the bazooka effectively made a single soldier as powerful as a tank, so the weapon was used extensively during the war and was highly regarded by the troops using it.
U.S. 4.5-Inch Barrage Rockets
The U.S. Army made extensive use of barrage rockets during World War II. The first of these was originally conceived as an air-to-surface missile to be fired from aircraft at targets on the ground. A prototype barrage rocket was fashioned from a fire extinguisher, and led to the development of barrage rockets having diameters of 3.25 or 4.5 inches.
The 4.5-inch version of the barrage rocket quickly became a popular weapon among all of the branches of service, and was widely used during the war in a number of variants. Each variant varied in length, but was generally about three feet long.
The M-8 was fired from truck-mounted or tank-mounted eight-tube launchers called the “Xylophone” or 60-tube launchers called the “Calliope”. A variety of different jeep-mounted launchers were used for the M-8, as was a single-tube launcher used during jungle fighting.
An air-launched version of the M-8 was fired against Japanese positions on Burma in the winter of 1943-44. This marked the first time that U.S. rockets were fired offensively from the air. The air-launched M-8 was capable of achieving a maximum speed of 600 m.p.h.
The M-12 sported collapsible fins and was fired from plastic tripods, while the M-16 was fired from 24-tube launchers called “Honeycomb” or 60-tube launchers called “Hornet’s Nest”. The M-16 could also be fired from Navy ships to soften enemy position prior to marine landings.
The “Old Faithful” was fired from landing craft as they approached beaches and was considered an effective method of continuing the softening of enemy defensive positions after artillery barrages ceased.
Finally, the “Super 4.5-Incher” was an air-launched missile which was six feet long and could achieve a maximum range of two miles at a maximum speed of 900 m.p.h. The missile employed four fixed stabilization fins. Although it was an effective early version of a winged cruise missile, it was tested but never deployed during the war.
Other U.S. Barrage Rockets
In addition to the multiple-use 4.5-inch barrage rockets, U.S. forces also developed and made use of a number of different barrage rockets. These were deployed on land and at sea.
A 3.5-inch diameter barrage rocket called “Spinner” was developed for the Marines and was able to reach maximum speeds of 435 m.p.h. The “Spinner” had a maximum range of two miles but was never deployed during the war.
The 3.5-inch diameter “Spinner” gave way to a 5-inch diameter version called the “Spinner Beach Barrage Rocket” that was designed for the Navy. The missile had interchangeable warheads that could deploy explosive, smoke, chemical, armor-piercing or pyrotechnic payloads.
A 5-inch diameter “High-Velocity Spin-stabilized Rocket” (HVSR) was fired from PT boats toward enemy ships. HVSR rockets were also fired from landing craft and even from the submarine “Barp” from a deck-mounted automatic launcher. HVSR rockets were used most extensively at Iwo Jima and Okinawa. Ships could launch up to 500 HSVR rockets per minute if need be.
Powerful 7.2-inch diameter demolition rockets were designed to be fired at bunkers and ground fortifications. The Army fired them from a 20-tube launcher called “Whiz Bang” while the Navy fired them from a 24-tube launcher called “Grand Slam”. The Navy also outfitted landing craft with a 120-tube launcher called “Woofus”.
The Navy also developed a barrage rocket that carried an anti-submarine bomb. The rocket/bomb combinations were known as “Mousetraps” and were typically fired from a ship toward a located submarine. “Mousetraps” accounted for a number of submarine kills prior to the end of the war.
U.S. Guided Bombs
Although guided bombs were not rockets in the traditional sense, they were technically advanced weapons that could be guided toward their intended targets by a number of methods. Most incorporated combinations of wings, steerable fins and propellers that could be controlled from airborne bombardiers.
The GB-1 (GB stood for “Guided Bomb”) was a 2,000-pound bomb which incorporated wings and was controlled by a television/radio guidance system. The VB-1 (VB stood for “Vertical Bomb”) was named “Azon” and was radio-guided by a series of moveable tail fins controlled by an airborne bombardier. Clusters of five “Azon” bombs could be dropped simultaneously if weather was cooperative.
The VB-1 was followed by a series of VB-series guided bombs, including the VB-3, named “Razon”, which had a variable range. The VB-6 was able to home in on a target through the use of a heat-seeking guidance system. The VB-10, VB-11 and VB-12, named “Roc”, each employed television/radio guidance systems.
The most impressive of the VB-series guided bombs was the VB-13, named “Tarzon”. It weighed 20,000 pounds and employed a 54-inch diameter lift shroud. The entire bomb was about 20 feet long, and was used to attack battleships and heavy fortifications.
The Navy developed a guided bomb which employed a retro-firing rocket motor. The rocket motor was fired briefly to allow the bomb to overcome the inertia of the aircraft and fall almost completely vertically toward its target.
This Navy guided bomb had a 7.2-inch diameter and could carry a 35-pound explosive payload. It was responsible for a number of submarine kills, including the last German submarine destroyed during World War II on April 30, 1945 in the Bay of Biscay. The PBY5A Catalina which first test-fired this guided bomb is considered to be the first U.S. aircraft to launch a rocket.
U.S. Air-To-Surface Missiles
A number of traditional barrage rockets were adapted to be launched from aircraft toward targets on the ground. These included the 3.5-inch diameter “Forward Firing Aircraft Rocket” (FFAR), which was 4.58 feet long and weighed about 54.5 pounds. The rocket had a range of under one mile and was used primarily against submarines and ships.
A 5-inch diameter version of the FFAR was 5.4 feet long and weighed about 80 pounds. It was typically fired against land-based or ship-based anti-aircraft artillery.
The 5-inch diameter “High Velocity Aircraft Rocket” (HVAR) was slightly longer than the 5-inch diameter FFAR and was nicknamed “Holy Moses”. HVAR rockets were deployed in large numbers, with about one million of the rockets produced before the end of the war.
The largest of the U.S. forward-firing aircraft rockets was the “Tiny Tim”, which was 10.25 feet long and had a diameter of 11.75 inches. Each rocket weighed about 1,284 pounds and was primarily launched against fortified pillboxes and bunkers on the Japanese home islands.
Although the “Tiny Tim” had a range of under one mile, a 30,000-pound thrust motor coupled with a maximum speed of 550 m.p.h. and a 150-pound explosive payload made the rocket as powerful as a 12-inch naval artillery shell. Each “Tiny Tim” was ignited by a lanyard mechanism as the rocket was dropped from its bomb rack.
More advanced U.S. air-to-surface missiles included the “Bat”, a longer-range radar-guided missile that was 12 feet long and could carry a 1,000-pound payload. The “Bat” had a maximum range of 20 miles and could achieve a maximum speed of 300 m.p.h. In April, 1945 a “Bat” missile sank a Japanese submarine at a distance of 20 miles from the launching aircraft.
The “Gargoyle” missile was originally designed as a guided bomb but was ultimately given a liquid-fueled rocket engine. The “Gargoyle” missile was approved for production in May, 1945 but was never used during the war.
U.S. Air-To-Air Missiles
Air-to-air missiles were not a high priority for the U.S. military since they did not become widely available until after Allied forces had already achieved air supremacy.
Traditional 4.5-inch diameter barrage rockets were adapted for use in air-to-air applications, but these were unguided. A fighter-based version was called the T-22, while another version was designed to be fired by a bomber’s tail gunner at enemy fighters.
U.S. Surface-To-Air Missiles
The U.S. military did not consider surface-to-air missiles to be a wartime priority because of the remote possibility that enemy aircraft would be able to penetrate U.S. airspace. However, as Japanese kamikaze attacks posed a significant threat to U.S. Navy vessels, two important research programs dawned near the end of the war.
The Little Joe missile was controlled by a gyroscopic stabilizer combined with commands from a radio guidance/optical tracking system. Its explosive warhead was designed to detonate by a proximity fuse as it approached its target. Each Little Joe missile was 11.34 feet long, had a diameter of 22.7 inches and weighed about 1,210 pounds.
Using a solid-fueled booster engine and a solid-fueled sustainer engine, the Little Joe could reach a maximum altitude of 1.5 miles at a maximum speed of 400 m.p.h. The Little Joe program had promise, but was canceled because development of the missile was considered to be too time consuming to be effective.
Development of the Lark began in 1944 on a schedule which was accelerated to accommodate for weaknesses in the Little Joe program. The Lark was 18.5 feet long, had a diameter of 18 inches and weighed about 2,000 pounds. It could reach a maximum altitude of four miles at a maximum speed of 600 m.p.h.
The Lark was launched by two solid-fueled booster engines and powered in flight by a tandem of two liquid-fueled sustainer engines, one of which was intended to be used as a back-up if the missile failed to reach its desired speed. The Lark had four fins and four wings, employed a radio-guided mid-course correction system and a semi-active homing device.
Although the Lark could not be developed in time for use during World War II, it did continue to be an active program following the war. In fact, Lark was one of the earliest missile programs to be tested at Cape Canaveral, with Lark flights beginning there in 1950.
U.S. Jet-Assisted Take-Off Programs
Scientists at California Institute of Technology successfully developed solid-fueled Jet-Assisted Take-Off (JATO) units for wartime deployment. JATO units with 200-pound, 500-pound and 1,000-pound thrusts were manufactured by Aerojet Engineering Corporation prior to the end of the war.
In addition, Dr. Robert Goddard participated in U.S. Navy research efforts to develop a liquid-propellant JATO unit to aid in the launching of PBY seaplanes. A 3,000-pound thrust JATO unit was developed, and manufactured by Reaction Motors, Inc. for wartime use. This JATO unit burned a combination of liquid oxygen and water-diluted gasoline.
U.S. Navy JATO research also resulted in a test vehicle called Gorgon, which was originally designed as a JATO unit but was adapted for use as an air-to-air missile. Several different configurations of the Gorgon emerged, but none were ever deployed during the war.
British War Rockets
The British military was able to develop and deploy a number of potent rockets for use during World War II. Perhaps the most lethal British package was the RAF Typhoon aircraft, which carried four 60-pound rockets under each wing.
This was an extremely effective weapon, and pioneered the “cab-rank” guidance technique. With this technique, a squadron of Typhoon aircraft could be guided to a target area by radio controllers on the ground. The aircraft would then attack an area in a nearly straight line. The method was reported to have wiped out entire German divisions.
It was likely that the British military would employ surface-to-air missiles due to the intensive air attacks carried out on British soil by German aircraft. These included a number of modified barrage rockets.
A finned version of a 3-inch diameter barrage rocket was deployed in models approaching six feet in length and weighing about 56 pounds. Another was about 4 feet in length and weighed about 110 pounds. The missiles were launched from double-barreled launchers called “projectors”.
Once launched, timed fuses were used to detonate an explosive payload if approaching aircraft targets at altitudes of up to four miles, while photoelectric fuses were used to detonate an explosive payload at higher altitudes.
The Snare project was designed to entangle the propellers of low-flying enemy aircraft in wire. Deployed on the bridge of a ship, a lanyard mechanism fired a modified 3-inch diameter barrage rocket which released a parachute at an altitude of 550 feet.
A 200-foot wire was attached to the parachute. A 90-foot trip wire attached to the ship was used to deploy another parachute located at the end of the 200-foot wire. As the wire floated toward the sea, it provided a deadly snare for aircraft flying at altitudes under 500 feet, primarily German dive bombers.
A winged missile called the Stooge was developed to provide a defense against kamikaze aircraft. The Stooge was 10.5 feet long and weighed about 740 pounds, of which 220 pounds was made up of an explosive warhead.
The Stooge was fired from a ramp launcher by four solid-fueled booster rockets which provided a combined 5,600-pound thrust for just under two seconds. A liquid-fueled sustainer engine with a 760-pound thrust carried the Stooge to a maximum speed of 500 m.p.h. The missile could be radio-guided to a maximum range of eight miles.
The British were also able to modify barrage rockets for use as air-to-surface missiles. These included the I-go IA and the I-go IB.
The I-go IA was 18.9 feet long and had a wingspan of 11.8 feet. The missile weighed about 3,085 pounds and had a maximum range of seven miles at a maximum speed of 340 m.p.h. The I-go IB was 13.4 feet long and had a wingspan of 8.5 feet. The missile weighed about 1,500 pounds and had a maximum range of five miles at a maximum speed of 340 m.p.h. Both I-go missiles were liquid-fueled.
The RP-3 was a 3-inch diameter spin-stabilized rocket projectile with a length of 5.35 feet. It weighed about 60 pounds and had a maximum speed of 1,000 m.p.h. and a maximum range of one mile. RP-3 missiles were typically launched in pairs toward targets on the ground.
The British also employed surface-to-surface barrage rockets in a variety of applications. These included 5-inch diameter cordite stick rocket launched from a two-legged, two-rail launcher. The launcher weighed just 40 pounds, and could be easily handled by a single soldier. These rockets could also be launched from a truck-mounted launcher with six pairs of rails.
These rockets were also adapted by the British Navy for deployment on landing craft. In this application, the rockets were fired from launchers called “Mattress Projectors” which could fire a salvo of 800 to 1,000 rockets in under 45 seconds to ranges of up to 3,000 yards.
A spiral rail launcher called a “Land Mattress” was also developed for the British Army. This allowed salvoes of large numbers of barrage rockets similar to those employed during landing operations to be deployed from ground positions as well.
Russian War Rockets
Russian forces deployed a number of barrage rockets which carried the name Katyusha, a designation which survives to this day. The standard Katyusha rocket used during World War II was 6 feet long, had a diameter of 5.1 inches and weighed about 92.5 pounds, of which about half was the weight of the explosive payload.
These Katyusha rockets burned solid-propellant double-base powder, and were launched from ground or truck-mounted racks. The missiles could achieve a maximum range of three miles.
Other versions of the Katyusha were launched from a mechanism called the “Stalin Organ”, a mobile launcher that could fire from 30 to 48 missiles at a time. Missiles launched in this manner typically had a diameter of 3.3 inches, weighed about 17.5 pounds and had a maximum range of three miles. A 30-pound version of the missile had a maximum range of six miles.
The Russians were able to use air-to-surface missiles quite early in the war, having fired missiles from aircraft toward troops and vehicles beginning in 1941. The most common were 2 feet long, had a diameter of 3.2 inches and weighed about 13.2 pounds.
These missiles were small, but effective. Although they carried an explosive payload weighing only about 2.2 pounds, the missiles were able to reach their targets at an impressive maximum speed of 1,150 m.p.h.
Rocket motors were attached to traditional bombs and dropped from Russian aircraft as well. These weighed between 56 and 220 pounds and were typically launched against tanks and armored vehicles. Certain Russian fighters were able to carry up to eight 56-pound rocket bombs on specially designed wing racks.
Japanese War Rockets
Although Japanese use of rockets during World War II was limited, the Japanese were able to improvise a variety of close-support barrage rockets which ranged in diameter from 3.2 to 18 inches and weights from 12 to 1,500 pounds. Ranges of these rockets was limited to a maximum of 500 feet. The Japanese also made limited use of a copy of the U.S. bazooka patterned after captured models.
Japanese surface-to-air missiles were adapted from barrage rockets. Two more advanced versions were called the Funryu 2 and the Funryu 4. The Funryu 2 was solid-fueled, 7.9 feet long, had a diameter of 12 inches and weighed about 815 pounds. The Funryu 4 was liquid-fueled, 13.1 feet long, had a diameter of 24 inches and weighed about 4,190 pounds.
The Funryu 2 could achieve a maximum speed of 525 m.p.h. and maximum altitude of three miles. The Funryu 4 could achieve a maximum speed of 650 m.p.h. and maximum altitude of 20 miles.
Japanese air-to-surface missiles consisted of traditional bombs attached to rocket motors. These missiles were unguided, weighed between 224 and 815 pounds and typically had a maximum range of three miles.
The Japanese also developed a rocket-propelled suicide plane called Ohka, which was a wooden monoplane with two stabilizing fins attached to a 2,645-pound bomb. The Ohka was 20 feet long and had a wingspan 16.4 feet. It was carried into action by another aircraft, then was detached and glided to a maximum range of 50 miles toward its target.
The Ohka was largely ineffective because it had a maximum glide speed of 230 m.p.h. and could easily be intercepted by aircraft or artillery. But, three 1,700-pound solid-fueled rocket motors could provide the Ohka with a maximum speed of 600 m.p.h. for about ten seconds. The Ohka was nicknamed Baka by Allied forces, the Japanese word for “fool”
French Wartime Rocket Research
Limited rocketry research was conducted in France during World War II, but never led to weapons applications. French rocket pioneers Robert Esnault-Pelterie and Henri F. Melot continued research they had begun before the war. The scientists developed a number of prototype solid-fueled and liquid-fueled rocket motor designs, but their work was terminated after German occupation.
Clandestine rocketry research was conducted during World War II by Colonel Joseph Dubouloz and resulted in the development of the first French liquid-fueled rocket, called the EA-1941. Static tests of the rocket began in November, 1941 with test launches from Algeria scheduled for 1942. Because of fighting in Algeria, EA-1941 test launches were postponed until after French liberation.
U.S. Wartime Rocket Research
By the close of World War II, the U.S. military had already begun rocketry research that would aid in the development of future rocket and missile programs. In fact, two of the most important companies in the development of U.S. rocket and missile programs were already active during World War II.
In 1941, Reaction Motors, Inc. of Pompton Plains, New Jersey became the first company solely dedicated to the development of rocket technology. The company was formed by members of the American Rocket Society and manufactured innovative Jet-Assisted Take-Off (JATO) units and missile test articles.
Also during World War II, Aerojet Engineering Corporation of Azusa, California was formed by a group associated with the California Institute of Technology. This company also manufactured JATO units and missile test articles.
Although U.S. rocketry research paled in comparison to developments made in Germany, a test bed was established that would prove fruitful in the development of long-range rockets after the war.
The Private rocket program was initiated at the Jet Propulsion Laboratory, an Army-sponsored research arm of the California Institute of Technology. The Private A rocket was 8 feet long and had a diameter of 2.8 feet. The Private A was powered by an Aerojet solid-propellant sustainer engine, with liftoff thrust provided by four modified 4.5-inch barrage rockets attached by a steel casing.
The Private A had four guiding fins at the rear and sported a tapered nose. The rocket was launched from a rectangular steel boom employing four guide rails. A total of 24 Private A rockets were tested. The maximum altitude achieved by a Private A rocket during these tests was 11.3 miles.
A follow-up to the Private A was called the Private F. The Private F was designed to test different types of lifting surfaces for guided missiles. The Private F employed a single guiding fin and two horizontal lifting surfaces at the tail of the rocket, plus two wings at the forward section.
Perhaps the most significant World War II research rocket was the Wac Corporal. The Wac designation stood for “Without Any Control”, with Corporal being the next rank above Private. Wac Corporal development began in 1944 when the Army Signal Corps requested a rocket capable of carrying a 25-pound scientific payload to altitudes approaching 100,000 feet.
A one-fifth scale version of the Wac Corporal was called the Baby Wac. The Baby Wac was introduced to test a proposed booster and sustainer engine combination and fin array for the full-scale version.
The full-scale Wac Corporal was 21 feet long, had a diameter of 12 inches and sported three tailfins. The Wac Corporal employed a solid-propellant first stage nicknamed “Tiny Tim” which could produce a liftoff thrust of 50,000 pounds. A solid-fueled Aerojet second stage could produce a thrust of 1,500 pounds.
Wac Corporal rockets were launched from a launch tower similar to those used for tests conducted by Dr. Robert Goddard. Test launches of the Wac Corporal were conducted at the White Sands Proving Ground in New Mexico, although tests of the rocket did not occur there until September, 1945 after World War II had ended.
Results from the Wac Corporal program were significant, with one of the rockets reaching a maximum altitude of 43.5 miles. The Wac Corporal program also yielded a second stage for captured German V-2 rockets, with the two-stage V-2 called Bumper-Wac. A Bumper-Wac became the first rocket to carry an object into space and also became the first type of rocket to be launched from Cape Canaveral.
The U.S. also experimented with rocket-powered aircraft during World War II, although none of the resulting vehicles were deployed during the war. The MX-324 was 14 feet long and had a wingspan of 38 feet. The rocket-powered aircraft was designed to fly a maximum range of 1,000 miles.
The MX-324 employed an Aerojet rocket motor. The vehicle could achieve a maximum speed of 550 m.p.h. with the pilot intended to lay prone in order to withstand high acceleration. Just three of the planes were ever built. Two were severely damaged during testing, and a third was dismantled.