Toss bombing

Last updated
"Over-the-shoulder" delivery Overtheshoulderbomb.jpg
“Over-the-shoulder” delivery

Toss bombing (sometimes known as loft bombing, and by the U.S. Air Force as the Low Altitude Bombing System, or LABS) is a method of bombing where the attacking aircraft pulls upward when releasing its bomb load, giving the bomb additional time of flight by starting its ballistic path with an upward vector.

Contents

The purpose of toss bombing is to compensate for the gravity drop of the bomb in flight, and allow an aircraft to bomb a target without flying directly over it. This is to avoid overflying a heavily defended target, or to distance the attacking aircraft from the blast effects of a nuclear (or conventional) bomb. [1]

Bomb tactics

Pop-up

In pop-up bombing, the pilot approaches from low altitude in level flight, and on cues from the computer pulls up at the last moment to release the bomb. Release usually occurs between 20° and 75° above the horizontal, causing the bomb to be tossed upward and forward, much like an underarm throw of a ball.

Level toss

Although "pop-up" bombing is generally characterized by its low-level approach, the same technique of a toss starting from level flight can be used at any altitude when it is not desirable to overfly the target. Additional altitude at release gives the bomb additional time of flight and range, at the cost (in the case of unguided munitions) of accuracy due to windage and the increased effect of a slight deviation in flight path.

Dive toss

The Dive-toss delivery technique was the first "toss" bombing method developed after WWII at the US Navy's rocket development center at Inyokern, California in 1947 as a method to attack heavily defended targets without unduly endangering the attacking aircraft. [2] Although toss bombing might seem the direct opposite to dive bombing, where the plane pitches downward to aim at its target, toss bombing is often performed with a short dive before the bomber raises its nose and releases its bomb. This variant is known as "dive tossing". This gives both the bomb and aircraft extra momentum, thereby helping the aircraft regain altitude after the release, and also ensuring that airspeed at the calculated release point is still sufficient to get the bomb to the target.

Over-the-shoulder

A more dynamic variant of toss bombing, called over-the-shoulder bombing, or the LABS (Low Altitude Bombing System) maneuver (known to pilots as the "idiot's loop"), is a particular kind of loft bombing where the bomb is released past the vertical so it is tossed back toward the target. This tactic was first made public on 7 May 1957 at Eglin AFB, when a B-47 entered its bombing run at low altitude, pulled up sharply (3.5 g) into a half loop, releasing its bomb under automatic control at a predetermined point in its climb, then executed a half roll, completing a maneuver similar to an Immelmann turn or Half Cuban Eight. The bomb continued upward for some time in a high arc before falling on a target which was a considerable distance from its point of release. In the meantime, the maneuver had allowed the bomber to change direction and distance itself from the target. [3]

Author and retired USAF F-84 pilot Richard Bach describes such an attack in his book Stranger to the Ground:

The last red-roofed village flashes below me, and the target, a pyramid of white barrels, is just visible at the end of its run-in line. Five hundred knots. Switch down, button pressed. Timers begin their timing, circuits are alerted for the drop. Inch down to treetop altitude. I do not often fly at 500 knots on the deck, and it is apparent that I am moving quickly. The barrels inflate. I see that their white paint is flaking. And the pyramid streaks beneath me. Back on the stick smoothly firmly to read four G on the accelerometer and center the needles of the indicator that is only used in nuke weapon drops and center them and hold it there and I'll bet those computers are grinding their little hearts out and all I can see is sky in the windscreen hold the G's keep the needles centered there's the sun going beneath me and WHAM.

My airplane rolls hard to the right and tucks more tightly into her loop and strains ahead even though we are upside down. The Shape has released me more than I have released it. The little white barrels are now six thousand feet directly beneath my canopy. I have no way to tell if it was a good drop or not. That was decided back with the charts and graphs and the dividers and the angles. I kept the needles centered, the computers did their task automatically, and the Device is on its way.

Tactical use

Toss bombing is generally used by pilots whenever it is not desirable to overfly the target with the aircraft at an altitude sufficient for dive-bombing or level bombing. Such cases include heavy anti-air defenses such as AAA and SAMs, when deploying powerful weapons such as 2,000 lb (910 kg) "iron bombs" or even tactical nuclear bombs, and the use of limited-aspect targeting devices for guided munitions.

To counter air defenses en route to the target, remaining at a low altitude for as long as possible allows the bomber to avoid radar and visual tracking and the launch envelope of older missile systems designed to be fired at targets overflying the missile site. However, a level pass at the target at low altitude will not only expose the aircraft to short-range defenses surrounding the target, but will place the aircraft in the bomb's blast radius. By executing a "pop-up" loft, on the other hand, the pilot releases the munition well outside the target area, out of range of air defenses. After release, the pilot can either dive back to low altitude or maintain the climb, in either case generally executing a sharp turn or "slice" away from the target. The blast produced by powerful munitions is thus (hopefully) avoided.

The value of toss-bombing was increased with the introduction of precision-guided munitions such as the laser-guided bomb. Previous "dumb bombs" required a very high degree of pilot and fire control computer precision to loft the bomb accurately to the target. Unguided loft bombing also generally called for the use of a larger bomb than would be necessary for a direct hit, in order to generate a larger blast that would destroy the target even if the bomb did not hit accurately due to windage or computer/pilot error. Laser-targeting (and other methods like GPS as used in the JDAM system) allows the bomb to correct minor deviations from the intended ballistic path after it has been released, making toss-bombing as accurate as level bombing while still providing most of the advantages of toss-bombing using unguided munitions. However, the targeting pods used to deliver guided munitions generally have a limit to their field of view; most specifically, the pod usually cannot look behind the aircraft at more than a certain angle. Lofting the bomb allows the pilot to keep the target in front of the aircraft and thus within the targeting pod's field of view for as long as possible.

"Dive-tossing" is generally used at moderate altitude (to allow for the dive) when the target, for whatever reason, cannot be designated precisely by radar. A target for instance may present too small a signature to be visible on radar (such as the entrance to an underground bunker) or may be indistinguishable in a group of radar returns. The pilot can in this case use a special "boresight" mode that allows the pilot to designate a target by pointing his aircraft directly at it. For a target on the ground, this means entering a dive. Thus designated, the pilot can then begin a climb, lofting the bomb at the target from a distance and regaining lost altitude at the same time.

Technology

Due to the intense pilot workload involved with flying and entering the window of opportunity, some aircraft are equipped with a “Toss Bomb Computer” (in US nuclear delivery, a part of the Low Altitude Bombing System) that enables the pilot to release the bomb at the correct angle. The Toss Bomb Computer takes airspeed inputs from the aircraft's pitot system, altitude inputs from the static system, attitude inputs from the gyroscopic system and inputs from weapons selectors signifying the type of bomb to calculate the appropriate release point of the ordnance. Instead of triggering the release directly, the pilot instead "consents" to release the weapon, then begins a steady climb. The computer then calculates the desired ballistic path, and when that path will be produced by the current aircraft attitude and airspeed, the computer releases the bomb. During the Second World War the engineers Erik Wilkenson and Torsten Faxén at Saab developed the first bomb sight for toss bombing. It was a mechanical computer that did the necessary calculations. It was first used in the Saab 17 and was standard on all Saab fighters up to and including Saab 32 Lansen. It was also sold to France, Switzerland, Denmark and USA and was used in for instance the Boeing B-47 Stratojet. [4]

While deployed in Europe with NATO, RCAF CF-104 fighter-bombers carried a Toss Bomb Computer until their nuclear role was eliminated by the Canadian government effective 1 January 1972.

The same computational solutions used in the LABS system are now incorporated into two of the major bombing modes (the computer-controlled CCRP and a dedicated visually oriented "Dive-Toss" mode) of the Fire Control Computer of modern strike fighters such as the F-15E and F-16. As with LABS, the pilot designates their desired impact point, then consents to release while executing a climb, and the computer controls the actual release of the bomb. The integration into the FCC simplifies the pilot's workload by allowing the same bombing mode (CCRP) to be used for level, dive and loft bombing, providing similar cues in the pilot's displays regardless of the tactics used, since the computer simply sees it as the release point getting closer.

See also

Related Research Articles

<span class="mw-page-title-main">Interceptor aircraft</span> Fighter aircraft classification; tasked with defensive interception of enemy aircraft

An interceptor aircraft, or simply interceptor, is a type of fighter aircraft designed specifically for the defensive interception role against an attacking enemy aircraft, particularly bombers and reconnaissance aircraft. Aircraft that are capable of being or are employed as both ‘standard’ air superiority fighters and as interceptors are sometimes known as fighter-interceptors. There are two general classes of interceptor: light fighters, designed for high performance over short range; and heavy fighters, which are intended to operate over longer ranges, in contested airspace and adverse meteorological conditions. While the second type was exemplified historically by specialized night fighter and all-weather interceptor designs, the integration of mid-air refueling, satellite navigation, on-board radar and beyond visual range (BVR) missile systems since the 1960s has allowed most frontline fighter designs to fill the roles once reserved for specialised night/all-weather fighters.

<span class="mw-page-title-main">Dive bomber</span> Bomber aircraft that dives directly at its targets

A dive bomber is a bomber aircraft that dives directly at its targets in order to provide greater accuracy for the bomb it drops. Diving towards the target simplifies the bomb's trajectory and allows the pilot to keep visual contact throughout the bomb run. This allows attacks on point targets and ships, which were difficult to attack with conventional level bombers, even en masse.

<span class="mw-page-title-main">Unguided bomb</span> Aerial bomb without guidance, designed for ballistic delivery

An unguided bomb, also known as a free-fall bomb, gravity bomb, dumb bomb, or iron bomb, is an aircraft-dropped bomb that does not contain a guidance system and hence simply follows a ballistic trajectory. It includes all aircraft bombs in general service until the latter half of World War II, and the vast majority until the late 1980s, which were known simply as "bombs".

<span class="mw-page-title-main">Glide bomb</span> Aerial weapon with flight control surfaces

A glide bomb or stand-off bomb is a standoff weapon with flight control surfaces to give it a flatter, gliding flight path than that of a conventional bomb without such surfaces. This allows it to be released at a distance from the target rather than right over it, allowing a successful attack without exposing the launching aircraft to air defenses near the target. Glide bombs can accurately deliver warheads in a manner comparable to cruise missiles at a fraction of the cost—sometimes by installing flight control kits on simple unguided bombs—and they are very difficult for surface-to-air missiles to intercept due to their tiny radar signatures and short flight times. The only effective countermeasure is to intercept launching aircraft before they approach within range, making glide bombs very potent weapons where wartime exigencies prevent this.

<span class="mw-page-title-main">Ejection seat</span> Emergency aircraft escape system

In aircraft, an ejection seat or ejector seat is a system designed to rescue the pilot or other crew of an aircraft in an emergency. In most designs, the seat is propelled out of the aircraft by an explosive charge or rocket motor, carrying the pilot with it. The concept of an ejectable escape crew capsule has also been tried. Once clear of the aircraft, the ejection seat deploys a parachute. Ejection seats are common on certain types of military aircraft.

<span class="mw-page-title-main">Norden bombsight</span> Targeting device on US bombers during World War II, Korean War, and Vietnam War

The Norden Mk. XV, known as the Norden M series in U.S. Army service, is a bombsight that was used by the United States Army Air Forces (USAAF) and the United States Navy during World War II, and the United States Air Force in the Korean and the Vietnam Wars. It was an early tachometric design that directly measured the aircraft's ground speed and direction, which older bombsights could only estimate with lengthy manual procedures. The Norden further improved on older designs by using an analog computer that continuously recalculated the bomb's impact point based on changing flight conditions, and an autopilot that reacted quickly and accurately to changes in the wind or other effects.

In aeronautics, a descent is any time period during air travel where an aircraft decreases altitude, and is the opposite of an ascent or climb.

<span class="mw-page-title-main">Fire-control system</span> Ranged weapon assistance system

A fire-control system (FCS) is a number of components working together, usually a gun data computer, a director and radar, which is designed to assist a ranged weapon system to target, track, and hit a target. It performs the same task as a human gunner firing a weapon, but attempts to do so faster and more accurately.

<span class="mw-page-title-main">Cobra maneuver</span> Dynamic deceleration of fighter aircraft

In aerobatics, the cobra maneuver, also called dynamic deceleration, among other names, is a dramatic and demanding maneuver in which an airplane flying at a moderate speed abruptly raises its nose momentarily to a vertical and slightly past vertical attitude, causing an extremely high angle of attack and momentarily stalling the plane, making a full-body air brake before dropping back to normal position, during which the aircraft does not change effective altitude.

<span class="mw-page-title-main">Pitot-static system</span> System of pressure-sensitive instruments used to determine an aircrafts speed, altitude, etc.

A pitot-static system is a system of pressure-sensitive instruments that is most often used in aviation to determine an aircraft's airspeed, Mach number, altitude, and altitude trend. A pitot-static system generally consists of a pitot tube, a static port, and the pitot-static instruments. Other instruments that might be connected are air data computers, flight data recorders, altitude encoders, cabin pressurization controllers, and various airspeed switches. Errors in pitot-static system readings can be extremely dangerous as the information obtained from the pitot static system, such as altitude, is potentially safety-critical. Several commercial airline disasters have been traced to a failure of the pitot-static system.

A Constantly Computed Impact Point (CCIP) is a calculation provided by a weapon's sighting system. It is a predicted point of impact found from the launch platform's movement, the target's movement, gravity, projectile launch velocity, projectile drag, and other factors that can be entered. It is usually displayed on the Head Up Display (HUD).

<span class="mw-page-title-main">Spice (bomb)</span> Guided bomb

The "SPICE" is an Israeli-developed, EO/GPS- guidance kit used for converting air-droppable unguided bombs into precision-guided bombs.

<span class="mw-page-title-main">Bombsight</span> Aircraft system for aiming bombs

A bombsight is a device used by military aircraft to drop bombs accurately. Bombsights, a feature of combat aircraft since World War I, were first found on purpose-designed bomber aircraft and then moved to fighter-bombers and modern tactical aircraft as those aircraft took up the brunt of the bombing role.

<span class="mw-page-title-main">1994 Fairchild Air Force Base B-52 crash</span> 1994 military aviation accident in Washington state

On Friday, 24 June 1994, a United States Air Force (USAF) Boeing B-52 Stratofortress crashed at Fairchild Air Force Base, Washington, United States, after its pilot, Lieutenant Colonel Arthur "Bud" Holland, maneuvered the bomber beyond its operational limits and lost control. The aircraft stalled, fell to the ground and exploded, killing Holland and the other three crew aboard. The crash was captured on video and was shown repeatedly on news broadcasts throughout the world.

<span class="mw-page-title-main">Mark XIV bomb sight</span> Bombsight used by the RAF during World War II

The Mark XIV Bomb Sight was a bombsight developed by Royal Air Force (RAF) Bomber Command during the Second World War. It was also known as the Blackett sight after its primary inventor, P. M. S. Blackett. Production of a slightly modified version was also undertaken in the United States as the Sperry T-1, which was interchangeable with the UK-built version. It was the RAF's standard bombsight for the second half of the war.

<span class="mw-page-title-main">Precision-guided munition</span> "Smart bombs", used to strike targets precisely

A precision-guided munition is a guided munition intended to precisely hit a specific target, to minimize collateral damage and increase lethality against intended targets. During the First Gulf War guided munitions accounted for only 9% of weapons fired, but accounted for 75% of all successful hits. Despite guided weapons generally being used on more difficult targets, they were still 35 times more likely to destroy their targets per weapon dropped.

<span class="mw-page-title-main">Course Setting Bomb Sight</span> Vector bombsight

The Course Setting Bomb Sight (CSBS) is the canonical vector bombsight, the first practical system for properly accounting for the effects of wind when dropping bombs. It is also widely referred to as the Wimperis sight after its inventor, Harry Wimperis.

The Vickers Blue Boar was a family of British air-launched television-guided glide bombs of the 1950s which was cancelled during development. A key role was as an anti-shipping missile, using its guidance system to attack the moving targets. It would also replace unguided bombs between 5,000 and 10,000 lb against point targets, or be equipped with a nuclear warhead. A smaller 1,000 lb (450 kg) version was also developed for testing. The name is a randomly assigned rainbow code.

A wingover is an aerobatic maneuver in which an airplane makes a steep climb, followed by a vertical flat-turn. The maneuver ends with a short dive as the plane gently levels out, flying in the opposite direction from which the maneuver began.

<span class="mw-page-title-main">Low Level Bombsight, Mark III</span>

The Low Level Bombsight, Mark III, sometimes known as the Angular Velocity Sight, was a Royal Air Force (RAF) bombsight designed for attacks by aircraft flying below 1,000 feet (300 m) altitude. It combined components of the Mark XIV bomb sight with a new mechanical computer. It featured a unique solution for timing the drop, projecting a moving display onto a reflector sight that matched the apparent motion of the target at the right instant.

References

  1. Cochrane, Rexmond C. (1966). "The Radio Proximity Fuze". A History of the National Bureau of Standards (PDF). Measures For Progress. U.S. Dept of Commerce. p. 397.
  2. "Smash Hits" Popular Mechanics, March 1947, p. 113, see texts p. 115.
  3. Knaack, Marcelle Size, Post-World War II Bombers, 1945–1973. Washington, DC: Office of Air Force History, 1988, ISBN   0-16-002260-6, p. 138.
  4. Ny Teknik: Svenskt bombsikte blev en världshit