The raw materials go boom
The Mark-80 series bombs, which are the heart of an LGB, are still in use today. Developed in the 1950s, at the U.S. Navy's Weapons Development Center near Ridgecrest, Calif. better known as China Lake, the Mark-80 series bombs are called "Low Drag, General Purpose," LDGP, bombs by the U.S. military because they have what is generally known as a slick low drag shape. These bombs do not add too much drag to supersonic aircraft -- important when the fighter drivers professional motto is "Speed is Life."
The bombs were developed by Ed Heinemann, who also designed and developed the Douglas A-4 "Skyhawk," because the "fat" or bulbous shaped bombs of World War II created huge amounts of drag when slung under the wing of a fighter-bomber.
Heinemann set about to create a bomb which would not only glide through the air better but also be slimmer than the World War II era bombs. The Mark-80 series bombs are elongated with thin cast steel walls which fragment easily and give the Mark-80s a bigger punch in terms of fragmentations. Explosives within the bomb is called "Tritonal 80/20" because it is a 80-percent TNT and 20-percent aluminum binder/inhibitor. This mix lessens the explosive power of the TNT but creates a bomb which is stable in storage which lends itself well to use aboard aircraft carriers.
The bombs are the Mk-82, 500-pound, Mk-83, 1000-pound and Mk-84 2,000 pound weapons. The Air Force prefers the Mk-82 and Mk-84 bombs, while the standard bomb of the U.S. Navy is the Mk-83.
Word and his Texas Instruments team started out with surplus World War II bombs because it was an Air Force contract and the Air Force had resisted purchasing bomb shapes -- slick or otherwise -- made by the Navy. The blue suiters wanted to develop their own bombs.
"We started with the old 750-pound bombs which were hard to control," said Word. " The Navy had the slick 1,000 Mark-80 series. There was a whole bunch of Mk-117 75-pounders and Mk-118 3,000 pounders left in the arsenal from World War II. Well, here's that interservice rivalry again. The Air Force didn't want to use the Navy bomb shapes -- which were slicker and more aerodynamic. They wanted to go off and develop themselves some more bombs. And DoD squashed that real quick. They said the Mark-80 series was going to be the standard bomb for all the services -- end of subject. That's why, about the time Paveway got rolling we switched to the Mk-82 and the Mk-84 -- the 500-pounder and the 2000-pounder. Throughout Vietnam, we really built kits that were canards and control groups that were sized for the Mk-82 and the Mk-84s, but in the beginning during the development phase our customer was the Air Force and we used those surplus bombs from World War II. "
Although the project name for the early laser guided bomb was Paveway I, the Air Force called it the BOLT-117 (BOmb, Laser Terminal-117) and it consisted of a standard 750-pound bomb case with a KMU-342 laser guidance and control kit. Today, the Paveway II series uses the MAU-169E/B guidance group and the Paveway III utilizes the vastly improved WGU-12B, -36A/B or -39/B guidance group. The difference between the first Paveways and the ones in use today are like the difference between jet and prop driven fighters. The Paveway III is so sophisticated it can be tossed from almost 20 miles out and an autopilot will guide the bomb to its target. This allows the aircrews a greater standoff range and the ability to avoid not only enemy guns and surface to air missiles but also gives them a chance to avoid detection all together.
-- Shelby G. Spires