Tag Archives: vietnam

Wild Weasel

With the late 1965 introduction of the S-75 (SA-2) surface to air missile system in North Vietnam, the US Air Force began looking for methods to counter this deadly threat to its strike forces. Locating and suppressing batteries of SAMs was a challenging role, hampered not just by the difficulty of the mission, but by poor equipment. Two seat F-100F fighters were the first platform used. But they had virtually no sensors beyond the human eyeball. The F-100 also had limited range and payload. The crews of these SAM hunters lacked almost everything but sheer guts. They cheerfully took on the role of attacking not just into the teeth of the enemy’s defenses, but the very defenses themselves. This “in your face” boldness led them to name themselves the Wild Weasels. Their motto, YGBSM, similarly noted their valor.

Soon after they began operations, the need for more range and payload, and room for growth for sensors lead the Air Force to assign the Wild Weasels the F-105F two-seat operational trainer version of the Thud. Of 143 “F” models built, eventually 54 were converted to EF-105F* configuration. Added Radar Homing and Warning devices and receivers allowed these Wild Weasels to locate, triangulate, and range the location of SAM sites based on the transmissions of their search and fire control radars.

Even more useful, the EF-105F added the AGM-45 Shrike anti-radiation missile to the available weapons. The Shrike, modified from the design of the AIM-7 Sparrow III missile, had a passive seeker that homed in on the fire control radar of the SA-2. Vietnamese radar operators could avoid the Shrike by shutting down their radar, but while that radar was down, the Weasel crews could close in and attack with conventional bombs and cluster munitions. More importantly, while the SAM site was suppressed, the main body of a strike force could carry out their mission unmolested by SAMs.


Further improvements to the “F” led to the F-105G** which served as the Air Force’s primary Suppression of Enemy Air Defenses (SEAD) platform until replaced by the F-4G Advanced Wild Weasel. The F-4G was replaced shortly after Desert Storm by the F-16CJ Wild Weasel.

*Not an official designation, it was still handy to differentiate them from vanilla two-seater Thuds.

**This time an official designation.

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Filed under Air Force, history, war

The Battle of Ia Drang

Today is the anniversary of the start of the Battle of Ia Drang, the first major engagement of US forces in Vietnam against the North Vietnamese Army. The 1st Cavalry Division, still learning how to employ an airmobile division, found itself locked in battle with two regiments of the NVA, themselves just learning how best to fight the Americans.

Vietnam tends to be thought of as a guerrilla war, but make no mistake, this was a conventional force-on-force engagement. Both sides were well equipped and armed, trained, and had some previous battle experience. And both sides learned lessons that would influence they way they fought each other for the next five years.

The battle has been memorialized for those of us of a younger generation both by LTG Hal Moore’s book, We Were Soldier’s Once, And Young, and the film adaptation We Were Soldiers.

LZ X-Ray, 14 NOV 65, before the engagement

In the early ‘90s, LTG Moore gave a talk to all the NCOs of the 4th Infantry Division about the battle (not often you have three star generals, even retired, giving NCO Professional Development).

I could address the technical and tactical lessons learned here, but for me, the lessons that always stood out were that young American soldiers, when faced with a daunting situation, backed by quality training, will display fortitude, resilience, ferocity, tenacity, selflessness, intrepidity, and valor. It is the leadership’s challenge to ensure those displays are exercised in a worthy effort.

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Fire Support In Vietnam

Most of the video is just run of the mill artillery stuff, and thus not terribly interesting, but check out the three-shot grenade launcher at 6:10. What the heck is that thing?


Filed under Artillery, ducks, guns, helicopters

What the Captain Means

It’s old, the sound quality isn’t great, but I found it funny, and I like watching the planes. NSFW for language.

Written and recorded in Cam Ranh Bay, 1966, by Lt. Col. Joe Kent, Information Officer, 12th Tactical Fighter Wing.

(update: I corrected the year.)


Filed under Air Force, war

More Linebacker II

We talked about the Christmas Campaign a while ago. Would you like to ride along for a bit? Audio from one of the B-52s on a strike:

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Armored Recon – Wrong Turn with the ACRC

In the earlier post, I noted the 1950s requirement for the Armored Command and Recon Carrier (ACRC).   To meet the ACRC requirement, Chrysler offered an armored car while General Motors’ Cadillac Division proposed a small tracked vehicle.  The Army’s long standing bias killed the Chrysler proposal, and Cadillac moved forward with tracked prototypes under the designation T114.

Appearing in 1958, the T114 used a small block Chevy 283 V-8 gasoline engine (a military version of the same engine found in cars of the time).  Cadillac used many other “off the shelf” components.  I cannot find firm documentation, but some suggest suspension components were from the M56 Scorpion, also built by Cadillac (although certainly NOT the road wheels). The tracks were “continuous band” somewhat reminiscent of the old half-track type used in World War II, and also similar to that used on the M56.

m114 capg copy

T114 Prototype

The T114′s crew included a TC, observer, and driver, with a jump seat for a fourth crew if needed.  The prototype weighed under seven tons and stood just short of seven feet tall.  With the front mounted engine, the turret sat to the rear of the fighting compartment.  The river sat in the left front and an observer’s station was to the right side.  The Army tested several armament configurations, to include some with a mind to the anti-tank role.

T114 Prototype with Autoloading 106mm Recoilless Rifle

But after full testing, the Army requested some changes before production.  Production ACRC featured a round, swing opening rear hatch.  As a cost savings measure, the main gun chosen was a .50-cal M2 machine gun, mounted on a pintle outside a large commander’s copula, instead of the turret.   Repositioned to the back right of the crew compartment, the observer’s position gained a top hatch and .30-cal machine gun.  An inch and a quarter of aluminum protected the crew from light arms and shell fragments.


M114 Side Profile (Bradley IFV Prototype behind)

The track was amphibious, transportable in theater support cargo aircraft of the era, and air-drop capable.

CH54-A Carrying M114

M114 under a Sikorsky S-64 (CH-54)

Entering production in 1962, the initial M114 model used the same V-8 car engine of the prototype. That’s why the “rumble” you hear in this video sounds familiar:

All told Cadillac produced just over 1200 of the ACRCs in the next few years.  Early on, an M-60 machine gun replaced the older .30-caliber for the observer.  About mid-way through the production run, a new traverse and elevation system allowed the TC to work the .50-cal while buttoned up, necessitating the nomenclature change to M114A1.  A non-factory modification replaced the .50-cal with a 20-mm M139 Hispano-Suiza cannon.  Thus armed the original M114s became M114E2 while those with the improved main gun mount were M114A1E1.


M114A2 with 20mm Cannon

In armored cavalry units, scout teams used the M114s.  A scout platoon of the time included a squad with two sections with two M114s each (four total). While the intent was a mix of 20mm and .50-cal armed M114s, this was not always met.  The platoon leader rode in his “command” M114.  The rest of the platoon consisted of an infantry squad in a M113, a M106 self-propelled 4.2-inch mortar, and three M-60 tanks. Airborne units differed, of course, using the M114s in conjunction with M56 Scorpions and jeeps.  Higher up in the formations, company commanders and battalion commanders in armored units rode in M114s configured as command tracks.  Apparently with the short production run, none of the M114s ever saw use in the ambulance or gun towing roles.

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Front View of M114

In service, the shortfalls of the M114 stood out in comparison to the M113 Armored Personnel Carrier.  The V-8 engine, while sufficient for a family car, was not strong enough for a fighting vehicle.  The M114 reached 36 mph on roads, slightly slower than the base M113s.  The front hull overhang presented problems when negotiating ditches.  Low ground clearance between the tracks, required to keep the height down, left the M114 prone to “bottoming out.”  And the 20mm gun suffered from poor reliability.


Close Up of the Tracks

Further, the “continuous band” track arrangement did not stand up well to the field.  When a band broke, the crew had no replacement options.  In peace time, they had to wait out the maintenance team.  In war, they’d have to abandon the vehicle!

Perhaps the hardest criticism of the M114 I’ve read was about space.  Cramped, the crew compartment lacked room to carry additional mission equipment or internal spall armor.  Certainly no room for ATGMs then entering the inventory, and thus no option to “up arm” the M114 as other countries did with their scout vehicles at the time.

But the Army had the M114 on hand and used it.  Large numbers went to Europe and Korea to arm the front line divisions there. Forty went to Vietnam, some going to the Army of the Republic of Vietnam (ARVN).  In addition to shortcomings mentioned above, the M114 proved no match for enemy mines.  While withdrawn from combat, the forces in CONUS, Korea, and Europe continued to use the little ACRC.  In the late 1960s as the M551 Sheridan tank arrived in sufficient numbers the M114′s days were limited.  In 1973, Army Chief of Staff General Creighton Abrams ordered the M114 out, officially replaced by scout-configured M113s.  But proving bureaucracy is stronger than steel, or a general’s directive, M114s clung to the property books until the close of that decade.

Released from TOEs, most of the M114s became range targets.  Anyone who’s visited Fort Irwin’s wonderful maneuver area has seen a number of these.  Several M114s became “gate guards” or went to other static displays.  And a few found their way to police forces, where their gasoline engine and thin armor was much less a liability.  XBrad featured a police-modified M114 in an earlier post.

In hindsight, the M114 was not only a failure but a wrong turn.  As the commercial says, there’s only one original jeep.  The M114 was the Army’s attempt to “SUV” the jeep concept – too small to haul anything significant or worth shooting, yet too large to hide.  And with respect to the maneuverability seen in the video lined above, road performance and cross-country performance are two different things.  Any scouting vehicle needs the later and, when cornered, trade punches with the “big boys.”  The M114 could do neither.

For those seeking more information about the M114, take a look at Eaglehorse (2-11 Cavalry) web site’s piece and the Tankmaster’s walk-around.


Filed under armor, history

The Thing! – M50 Ontos

Several folks mentioned the M50 Ontos (Greek for “The Thing”) in comments about the M56 Scorpion.  Rightfully so, as the two were somewhat contemporaries and initially conceived to fill the same basic airborne anti-tank requirements.   Each represented a different approach, in the days before guided missiles, to providing a heavy anti-tank weapon to the infantry.  While the M56 was for all practical purposes a motorized 90mm gun, the M50 used a set of recoilless rifles.

The story of the recoilless rifles themselves deserves detailed treatment in a separate set of posts.  Short end of that, in the early 1950s the Army fielded the M40 106mm recoilless rifle (which was really 105mm, but let’s save that for another day shall we?).  This large gun fired HEAT projectiles with an armor penetration of 400mm at a range of 3000 yards.  But the outfit was far too heavy, at over 450 pounds, for dismounted use.  Indeed the outfit pushed the limits of the standard 1/4-ton “jeep.”  What the Army wanted was an armored vehicle armed with the M40.

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M50 Ontos at the USMC Museum - Very Realistic!

Some sources credit General James Gavin with the idea for the Ontos.  However the number of prototype vehicles from the 1950s with recoilless rifles leads me to believe several brains came forward with the idea in parallel.  Regardless the basic Ontos chassis started with the T-55 utility vehicle, which was mostly a five-passenger lightly armored vehicle (the T-56 10-passenger “APC” was also offered).   Between 1952 and 1955, Allis-Chalmers developed a series of recoilless rifle carriers on the experimental chassis.  The T-164 carried four M-40s.  The T-165 mounted six.  The T-166 featured one rifle in a dis-mountable configuration.  And the un-built T-167 was to have eight!

USMC Museum 15 Jan 11 250

Front View of the M50

The Army liked the T-165 and proceeded to conduct advanced tests.  Dressed out, the T-165 weighed over 8 tons.  The Army actually ordered quantity production before canning the project in 1956.  Officially the Army cited the vehicle’s high profile, the limited ammunition supply, and external reloading procedures.  While not directly competing with the Ontos project, the M56 SPAT then in service weighed less, but left the crew completely exposed.  A better way to put it, the Army was already looking at ATGMs to counter the heavy Soviet tanks.

On the other hand, the Marines had a requirement for the old World War II style tank destroyer units.  They saw the Ontos as the answer to their needs.  Designated M50, the first batches of the Ontos used a six-cylinder truck engine.  After a short, two-year, production run, the Marines received just under 300.  When the engine proved under-powered, the Marines upgraded about half with an eight-cylinder engine, producing the M50A1.  Road speed remained at an impressive 30 mph.

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Running Gear of the Ontos

As mentioned, the M50 carried the impressive armament of six M40 Recoilless Rifles, three on each side suspended from a set of arms.  A traveling brace on the front hull supported the forward barrel of the lower rifles.  The arms connected to a turret, which allowed for an 80 degree traverse, 20 degree elevation, and 10 degree depression.  Instead of elaborate sighting arrangements, above the upper four rifles was a .50 caliber spotting machine gun.  The .50 caliber rounds followed a similar ballistic path to the big rifles.  So the commander simply fired the .50 cals and walked the larger rifles onto the target.

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Right Side Set of Rifles - Note Spotting MG

Three men crewed the Ontos – commander, driver, and loader. The rear compartment was so cramped that often the loader sat to the side of the turret.  In addition to the six rounds in the rifles, a tray under the crew compartment carried twelve more rounds.   A .30 or .50 caliber machine gun on the turret provided close in defense for the vehicle.  The armor was enough only for light arms and shrapnel.

The Ontos remained in Marine inventories as the first units deployed to Vietnam in the 1960s.  There the “Thing” saw wide service, but met practically no enemy armor.  Instead the big 106mm rifles fired high explosive rounds against enemy bunkers or M581 anti-personnel rounds.  The later, with a range of around 300 yards, fired 9500 flechette, with legendary effects against troops staging massed assaults.  The M50 appeared on news footage during the battle of Hue in 1968:

How’s that for some retro ‘splody?

You might also check out a rather extensive collection of photographs, resources, and links on the Ontos Crewmembers memorial webpage for more on the Ontos in Vietnam.

The Marines began phasing out the Ontos in 1969.  Some passed to Army units in Vietnam, who briefly operated them for base defense.  But after ten years of service, and no production lines, the Ontos rapidly faded from the picture to be replaced in their original role by TOW carrying jeeps and helicopters.

If I had to rate the Ontos, from the historian’s perspective, I’d call it rather useful but none-the-less an evolutionary dead-end.


Filed under armor, history

Past, Present and Future of Tactical Radios – Part 6

In part 5, I closed noting some shortfalls of the otherwise very remarkable AN/PRC-25 and the contemporary tactical radio sets:

  • Use of vacuum tube in the RF output component
  • Lacking support for electronic encryption
  • BA-386 power and life limitations
  • PRC-25 Used at squad levels where not intended by doctrine
  • Maintenance/logistic support chain

The first two issues were not new to the Army.  The intent (in my opinion) was to develop the follow on AN/PRC-77 as the “perfect” radio to address these issues.   But requirements from Vietnam hit before that radio was ready.  Externally indistinguishable from the PRC-25, the PRC-77 featured a new RF output component, removing the last vacuum tube.    The PRC-77 added circuitry to allow use  of cryptographic devices then being fielded in 1968.

AN/PRC-25 or 77 - can't tell from here!

The cryptographic devices issued to line units were the KY-38 NESTOR (more pictures here).  The KY-38 was as large as the PRC-77 and weighed nearly the same – effectively doubling the RTO’s load.

KY-38 - from Jerry Proc's website

An obvious question is why impose this device upon the warfighter in the first place?  Simple answer – because he asked for it.  Cold War planners assumed Soviet forces would use electronic intelligence gathering to harvest valuable information from combat radio networks.  The existing communications security practice, dating back to World War II, involved changing frequencies and call signs at intervals, code words, challenge-authentication tables, shackle codes, and other verbal tricks.  But these were mere obfuscation of information.  And such obfuscation consumed valuable time on both ends of the conversation.   The Army wanted a “green box” solution to provide end-to-end encryption of the signal.  In collaboration with the National Security Agency, the Army fielded the KY-8 for vehicle mounts, the KY-28 for aircraft, and aforementioned KY-38 for backpack use.

Further experience in Vietnam underscored the threat.  In December 1969, a unit in 1st Infantry Division uncovered an enemy radio intercept team using captured US equipment alongside Chinese and commercial radios.  Journals found in the stash included operational information ranging from the time/location of air strikes to unit statuses, all gleaned from the radio nets.  The nature of the logs indicated this was not a singular occurrence.  The communists learned the obfuscation techniques and, using today’s term, hacked the American radio nets.

The NESTOR series suffered from several drawbacks:

  • KY-38 at roughly the size and weight of the PRC-77 doubled the RTO’s load.
  • Special X-Mode cable between the radio and KY-38 supplied in limited quantities.
  • Battery powered KY-38 increased battery consumption rates.
  • Complex process to load the crypto variables.
  • Device Overheating and reliability issues.
  • Need to wait a second or two when starting transmission for the encryption to synch before speaking.  (A precious combat second…)

Clearly this was not the solution to address the radio-intercept threat.  In the field, units used the devices sparingly, and as result still faced the threat of enemy intercept.  Once again, the equipment lagged behind the requirement.

Regarding batteries, the issue of a magnesium-cell BA-4386 partially addressed the battery life problem.  The BA-4386 lasted longer than the older alkaline types.  But patrols still needed substantial quantities of these “bricks” – displacing rations, water, and ammunition in the packs.  With PRC-25/77s pushed down to squad levels, the operational tempo of war, and the introduction of the comsec equipment, battery supply barely kept up with demand.

The Army issued PRC-25/77s down to the squads in place of failed radios designed for that echelon.  The AN/PRC-34/36 set, developed concurrently with the VRC-12 series and PRC-25, failed to meet performance goals as a PRC-6 “handie-talkie” replacement.    The Army then developed the AN/PRT-4 and PRR-9 combination.  With a PRT-4 hand-carried transmitter and a PRR-9 helmet mounted receiver, the overall system was cumbersome.  Tested in Vietnam, the PRT-4/9 lacked range and difficult to operate.  A Navy derivative, the AN/PRC-88, combining both units into a single box, also failed.  Frustrations with these projects eventually lead the Marines to develop their own radio which eventually became the AN/PRC-68 (leading to the AN/PRC-126).  But that product was not in the field until well after Vietnam.

Regarding maintenance support and logistics the issue was hardware reliability rates.  Now I would not dispute the “it worked” perception for the infantryman on the line.  And certainly the PRC-25/77, as the VRC-12 too, were much more reliable than previous Army radios.  But, in order to sustain the warfighter in Vietnam, the Army maintained huge quantities of repair parts and replacement (float) radios.  Radio users and repairmen also adapted to meet the problems.  When shipment of individual repair modules resulted in damaged parts, further straining the system, the logisticians introduced air-cushioned “jiffy bags.”  When supplies of whip antennas in theater ran out, modification kits allowed the use of PRC-10 whips on PRC-25s.  Handsets were so sensitive to moisture that most operators resorted to encasing them in plastic bags.

The PRC-25/77 and VRC-12s, for all their solid state reliability, continued to tax the maintenance and supply systems.  To sustain a goal of 100% readiness of combat radios in the line units, the theater maintained as much as one-third more devices (some sources say even more) as ready replacements.  Large numbers of personnel deployed to theater to simply repair and reissue radio systems.

Consider those support requirements in context of the times.  The Army fought Vietnam, until the last phases, with a draftee army and with a “sky’s the limit” budget.   After Vietnam, the Army had to reorganize as a leaner, but still lethal, force.  This translated to, among dozens of other things at the warfighter level, the need for radios requiring less specialized maintenance and fewer supporting personnel.

In front of this “draw down” cycle, the perception leaving Vietnam was that technology had evolved to the point that even the “knuckle-draggers” could operate the radios.  From about 1972 on, all soldiers received basic radio operations training, not just those assigned as communications operators.  This presented a significant opportunity to trim down an infantry division, as in the TOEs up to 10% of the personnel were communications staff.

In the Army’s “dark age” from 1975 to 1982, the calls for a smaller force structure, better communications security, a squad radio solution, and more reliable hardware – all drove the Army to look for new radios after Vietnam.   Further another factor, not mentioned until now, was the emerging digitization of the battlefield.  After 1973, the digital facet to modern combat could not be ignored.  I will turn to the Army’s next major radio development, relating how SINCGARS arrived on the scene.


Filed under army, history

25th ID in Vietnam

I was poking around youtube looking for fuzzy kittens and came across this little clip. I hate Dan Rather, but it IS an interesting clip. Notice the M14s, and M14E2s. Also, the heavy artillery, the 175mm gun? Look at the size of the powder charge they put in that thing. No wonder the 175mm was the longest range tube we had.


Filed under army, ARMY TRAINING, ducks, guns, history


Boston.com has a photo essay of the Vietnam war, 35 years after the fall of Saigon.


Filed under army, ARMY TRAINING, history, marines, war

Retro Apache Pr0n…

When I put up my post on the Apache development, I asked BillT from Castle Argghhh! to take a look and let me know if I’d made any colossal blunders. As I fired off the email, I knew in my bones he was going to come back with a word about the Apache’s daddy, the venerable AH-1 Cobra. How did I know this? Bill is a retired Army Aviator (in fact, I believe he’s a Master Aviator), with combat time in Vietnam and long experience in attack and scout aviation. My request was like asking the owner of a ’64 Mustang to give me his thoughts on the new Dodge Magnum. Sure, he’ll help, but you know he’s gonna want to talk a little Mustang.

Almost from the first helicopter, people had the bright idea to arm them. Everyone in the Army knows to seek the high ground, and how much higher can you get than in a helicopter? But the concept was easier than the implementation. Early helicopters had little power, and were only able to lift relatively small loads. Think back to the opening shots of M*A*S*H. Not a lot of room there for lifting heavy stuff. Early helicopters were powered by piston engines. You could use a bigger engine to get more power, but the weight of the engine increased faster than the improvement in power. It wasn’t until the invention of the gas turbine that lightweight, powerful helicopters became a reality.

A gas turbine is a jet engine that transfers its power to a drive shaft, instead of pushing air out the back. The first practical gas turbine powered helicopter was the UH-1B Iroquois, far better known as the Huey. Early in the Vietnam war, Huey’s began to be used to ferry troops to the battle, saving time that would otherwise be spent walking in the woods. Unfortunately, the VC learned that they could predict where the Huey’s would land, and soon began laying ambushes for them. The Huey’s were tough, capable birds, but they can only take so much damage. What was needed was an escort to keep the VC’s heads down while the Huey’s landed and offloaded their troops. The Army quickly developed an armed version of the Huey, equipping it with machine guns and 2.75” rockets, just the thing to discourage the VC from shooting at the transports.

While the new gunship escorts were a great improvement over nothing, they still weren’t perfect. The extra weight of the guns, rockets and ammunition actually left the escorts slower than the transports.

The Army and Bell Helicopter took the parts of the helicopter that they liked, such as the rotor, transmission and basic engine, and developed a specialized gunship. By using a more powerful version of the basic engine (and not many aviators will ever complain about having more power) and using the smallest possible body, they were able to introduce a chopper that was both faster than the transports and more heavily armed than previous gunships. The AH-1G would be the Army’s primary gunship in the Vietnam war. Over 1,000 were produced.

Armed with two 6-barreled 7.62mm Mini-guns and 2.75” rocket pods, the AH-1G Cobra had plenty of firepower to suppress the VC when transports were landing or taking off at an LZ. In addition, they were used to provide close support for troops on the ground. In fact, some units were used primarily for this and were designated Ariel Rocket Artillery Battalions. Many a grunt blessed the familiar “Whop-whop-whop” sound of a Cobra overhead.

After the Vietnam War, the Army turned its attention back to Western Europe. The Army was in bad shape and facing a truly massive Soviet army. With budgets tight, forces demoralized and equipment obsolete, how would the Army be able to defeat the Soviets and prevent them from conquering Western Europe. The Army had a large supply of Cobras on hand, but rockets and Mini-guns were next to useless against tanks and armored personnel carriers. The answer lay with the TOW missile. TOW stands for Tube Launched, Optically tracked, Wire-guided missile. With a range of 3000 meters and a warhead capable of destroying any tank, the 70 pound missile gave the Cobra the firepower it needed to be useful on the battlefields of Europe. A new 20mm three barreled cannon was also added to deal with targets like trucks.

With this new, powerful anti-tank weapon, Army aviators began thinking beyond the front lines. By using the mobility of helicopters, they could search out and attack Soviet formations behind the front lines, before they were attacking our troops. In conjunction with the evolution of what would become AirLand Battle doctrine, the concept of “Deep Strike” came to be accepted. No longer would aviators be thought of as glorified truck drivers or simply flying artillery, but as Cavalry in the tradition of JEB Stuart and Nathan Bedford Forrest.


BillT was kind enough to give me his thoughts on the subject (see comments) and better yet, send pictures!


Filed under armor, ARMY TRAINING