Linebacker II- The Soviet View

It’s been almost two years since we wrote about Operation Linebacker II, the Christmas bombing campaign that was the swan song of US aerial attacks on North Vietnam.

“Spill” just alerted me to this piece on the campaign- a review of the campaign by the senior Soviet advisor to North Vietnam for air defense.

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A couple of points:

  • The lunacy of following SACs faulty mission planning made the North Vietnamese air defense problem much easier.
  • Air defense guns, while deadly to lower flying tactical aircraft, were virtually a non-starter against the B-52s.
  • The NV fighter regiments, while fairly capable during daylight, were ill trained to conduct night combat. Note that SAC planners had actually considered them the greater threat, in spite of the deployed aircrews argument that S-75 missiles (SA-2 SAMs) were the primary threat.
  • The fighter you don’t see is the one that kills you.
  • Electronic Warfare worked. Chaff worked too, and was cheaper. But a combination of chaff and jamming was better.
  • But jamming had to be well thought out. It could hurt almost as much as help.
  • The EA-6Bs weren’t allowed overland because of their highly sensitive jammers. The EB-66s weren’t allowed up north because they were vulnerable.
  • Even under the best of circumstances, it took a lot of SAMs to kill a plane.

416th Flight Test Squadron at Red Flag 2-12

Air Force pilots during the Vietnam War normally had a tour of 100 missions over North Vietnam. A disproportionate number of losses occurred during the first 10 missions of a tour. Pilots were simply overwhelmed by the requirements of flying combat in an incredibly dense air defense environment, in larger strike packages than they had ever practiced before.

Accordingly, the Air Force instituted Red Flag, an ongoing series of massive mock air battles over the Southwestern United States, with the goal of giving each aircrew its “first 10” in peacetime, rather than actual war. Large numbers of squadrons accross the entire spectrum of airpower would deploy to Nellis AFB just outside of Las Vegas. This package would closely resemble the actual force composition of a real air campaign, if on a somewhat smaller scale. Dedicated adversary fighter squadrons would play the role of an opposing air force. Complex, realistic ground based air defense threats were seeded throughout the training area, all in an attempt to provide a scenario that was “more real” than the real thing.

To this day, Red Flag is the capstone training exercise for Air Force units.

Friend of the blog ORPO1, a retired Navy Petty Officer, currently makes his living working as a contractor for the US Air Force, supporting the 416th Flight Test Squadron, responsible for ongoing engineering development for the F-16 Fighting Falcon. As as ED effort, the 416th, despite flying fighters, is an asset of Air Force Material Command.

In an unusual effort to provide a more realistic test environment, and validate the skills of the test pilots, the 416th deployed to Red Flag 2-12. And ORPO1 was right there with them. If you watch closely, you might even see his bald head a time or two.


USAV John U. D. Page

It’s not often I come across a type of ship in US service I’d never heard of before.

In the mid-1960s, the Roll-On/Roll-Off (RO/RO) type of transport vessel was first designed, the early example being USNS Comet. Trucks and tanks and other vehicles would simply be driven aboard a ship and parked. It was originally seen as a way of reducing the number of times a given cargo would have to be handled. Rather than unloading truckloads of cargo onto a ship and then unloading said cargoes off the ship into a truck at the destination, the reasoning was that loaded trucks could simply be shipped.

As a method of moving cargo, it was fairly inefficient The container carrying cargo ship would address that need in a far more efficient manner in just a few years.

But it was hardly a failure, as it turned out RO/RO was an excellent way of transporting the vehicles themselves to a theater of war.

If the RO/RO could berth in an established port, no problem. Simply lower the ramp to the quayside, and drive the vehicles off.

But many theaters, such as Vietnam, had only the most primitive port facilities, and often not even that. Another method of delivering the vehicles from ship to shore would be needed. The Army’s small LCM and LCU beaching craft would simply unable to unload vehicles fast enough.

Accordingly, the Army (the lead DoD agency for Over The Shore Logistics) developed the Beach Discharge Lighter.  Named the US Army Vessel John U.D. Page, the BDL was 338 feet long and displaced about 2000 tons. A flat, open vehicle deck supported a thin center island for the ships bridge and stack. A flat open area aft was designed to mate with the stern ramp of USNS Comet. A bow ramp was designed to discharge vehicles over a beach. Cyclodial propellers* gave the BDL excellent maneuverability, and the ability to turn within her own length.

The Page entered service in 1958, and self deployed across both the Atlantic and the Pacific. She spent much of the Vietnam war in those waters, facilitating the delivery of cargo both from RO/RO ships and conventional cargo ships to unimproved ports. The Page was the only vessel of the class built, and she served until 1985.



In the picture above, you see the page alongside a US Navy LST, and they’re of comparable size. But understand that the BDL was not designed to carry vehicles and cargo on long oceanic voyages, nor was she intended to support an assault landing. She lacked the berthing and messing spaces that an LST provided for vehicle crews, and her open deck, while facilitating rapid loading and unloading, would leave vehicles vulnerable to sea and wind damage on the open ocean. Her open deck, and larger bow ramp, allow her to carry larger vehicles than the LST could, for instance, later main battle tanks such as the M60.


* Fairly common now on tugboats and ferries, the CD drive was first tested in the US on a modified LSM.

Ivan Could Swim!

A Craig tank posting again.  Here’s another video from the American Wartime Museum open house:


Many will jump to compare the PT-76 to the M551 Sheridan.    But the Russian tank had been around some 15 years before the American tank even did test laps. While the American tank used a highly advanced (perhaps too advanced) hybrid gun-missile armament, the PT-76 used a tried-and-true 76mm main gun.  The gun fires both high velocity armor piercing (HVAP) and high explosive anti-tank (HEAT) rounds.  A 7.62 caliber coaxial machine gun complements the main gun.

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PT-76 on Display

The Russians kept the PT-76 in production through the late 1960s.  All told over 5000 rolled out of the factories.  Production variants introduced better NBC and night vision systems.  A few PT-85s were produced with an 85mm main gun.  And experimental versions featured 90mm or anti-tank missile armament.

The PT-76’s design put emphasis on amphibious capabilities.  In fact, the PT-76 came with water jets to allow speeds of 6 mph when swimming.

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Water Jet Exhaust

In addition to great amphibious capabilities, the PT-76 had a roomy interior and good cross country mobility.  But the tank’s armor was only good against rifle-caliber fire.  And the main gun lacked any stabilization.  You wouldn’t want to go toe-to-toe with enemy tanks.  However, the PT-76 was designed to operate and exploit the fringes of a defense line where enemy tanks were not supposed to be.

In Soviet service the PT-76s armed reconnaissance companies in line divisions and tank companies in the marine divisions.  Russia retains a significant number of the PT-76s.  Here’s an old documentary forwarded by the political officer (can anyone translate what he’s saying?):


With over 2000 exported, many nations around the world continue to operate the amphibious tanks.  Examples manned by the North Vietnamese participated in some of the few tank-vs-tank battles in the Vietnam War.  In fact, PT-76s were the first to fall victim to TOW missiles.

While technically the tank COULD be airdropped or air-transported, the Russians opted to use the ASU-57 and ASU-85 self-propelled guns in airborne formations (and later BMD series recon/carriers).

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Rear Deck of PT-76

Speaking of the ASU-85, that weapon used the chassis of the PT-76, with of course an 85 mm gun fixed in a superstructure.  Other systems using the PT-76 chassis include the BTR-50 amphibious carrier, the ZSU-23-4 self-propelled anti-aircraft gun, missile carriers, and various support vehicles.  The Chinese improved the basic design into their own Type 63 tank.

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Same Tank from Last Year's Open House

Certainly there are some features of the PT-76 that make me wish the US Army or Marine Corps had procured something similar.  On the other hand, the American habit of misusing light armor would make any “Yankee” version a death trap.

The Army’s Quest for its Own CAS – Part 4

At the end of the last post on Army close air support (CAS) developments from the early 1960s, I mentioned one last attempt by the Army to secure an organic fixed-winged CAS capability.  This effort occurred concurrently with the vertical take-off and landing (VTOL) tests, but had strong political backing.

To some degree, the Army’s tests with fast forward air control (FAC), attack jets, and VTOL from 1960 onward were spurred by interest from President John F. Kennedy to improve the arm’s capability in mid- and low-intensity conflicts.  Secretary of Defense Robert McNamara became a strong proponent for army aviation, as he factored ways to increase mobility and potency of the conventional forces.  McNamara merged two schools of thought with regard to Army aviation – those calling for more helicopters and those who wanted improved fixed-wing assets.  The former, involving the genesis of the airmobile concept, deserves full treatment in another post.  Regarding the later, I’ve given a cursory overview of the Army’s experiments with armed fixed-wing aircraft, but keep in mind also the procurement of some very capable theater transports in the time period.

In 1962, McNamara created a “Tactical Mobility Requirements Board” under Lieutenant General Hamilton Howze.  Commonly referred to as the “Howze Board,” the board’s main focus soon became air mobility.  As part of the airmobile concept, the Howze Board explored ways to use both rotary- and fixed-wing platforms to provide direct support.    Keep in mind that man of the jet-turbine powered helicopters (such as the UH-1,  just entering service in the early 1960s, so board members viewed that platform with potential, but had to consider the limitations of the airframes on hand.  But in 1962, the Army did have quantities of a short take-off and landing (STOL) observation plane with a weapons capability.

The Grumman OV-1 Mohawk came from a joint service project.  At the time the Army needed a replacement for the Cessna O-1 Bird Dog observation aircraft, and added the need for sophisticated sensor payloads (infa-red and radar in particular).  The Navy and Marines also wanted an observation plane, but required an armament payload.  After several years of design work, the Marines dropped from the project with concerns for the elaborate electronics packages associated with the sensors.  Air Force pressure made the Army drop any armament requirements.  So when the type first entered production in October 1959, the OV-1 was an unarmed observation plane… that happened to retain all the necessary “plumbing” to be armed.

OV-1A Mohawk

For those not familiar with the Mohawk, the aircraft possessed incredible rough field operating abilities.  Early Mohawks nearly reached 300 mph, but its empty weight of 11,000 pounds required a waiver to pass the Pace-Finletter memo restrictions.  And of course with that waiver, the Air Force insisted the OV-1 should not carry weapons – despite operating over the combat zone and possessing the ability to carry 3,200 pounds of external stores!

When Howze Board issued its recommendations (some sources say fall 1962), it projected a requirement for 24 fixed-wing attack aircraft in the airmobile divisions, 8 in each conventional division, and additional numbers in “separate aviation brigades.”  Of the aircraft available for this role, the board eyed the OV-1’s neglected weapons capability.  As the board’s findings circulated among decision makers, the Army secured approval for a “concept demonstration” of the enhanced airmobile concept, which would include Mohawks flying CAS.  Working with a team of Navy experts, the Army outfitted OV-1s to drop delayed fuse 1000 pound bombs using the two hard-points on the production aircraft.  Although very successful, the Air Force eyed the development with suspicion.

Encouraged, the Army sent fifty-four OV-1As back to Grumman for installation of six underwing pylons, sights, and other equipment to facilitate the CAS mission.  Re-designated JOV-1A, the armed Mohawks carried .50-caliber machine gun pods, rockets (either 2.75- or 5-inch), 500 pound bombs, and flares.  Just like that, the Army had its fixed-wing CAS.

With the involvement in Vietnam becoming more and more important, the Army sent six JOV-1As with the 23rd Special Warfare Aviation Detachment to Southeast Asia for operational tests.  With supportive and vocal responses from the field, the Army soon dispatched more armed Mohawks to Vietnam.  This move met with support again from McNamara, who felt any aircraft in the combat zone should be armed.  While somewhat fuzzy, the video here captures some of those armed Mohawks in operation.  Check out the crew loading the rockets:


But this proved to be the gilded hour of Army fixed-wing CAS.  By 1965, the Air Force had enough of the tests, demonstrations, and operational deployments of armed Mohawks.  Aside from the Army butting into the airspace with armed planes, the Army was also calling for more pilots to support anticipated expansion of the force.  The two services compromised with the Johnson-McConnell agreement in 1966.  Under those terms, the Army gave up both organic fixed-winged CAS and theater transport.  Not only did the Army give up the armed Mohawks, options on the “in the works” AV-8 Harrier, but also the most capable Caribou (CV-2 or C-7) and Buffalo (V-7 or C-8) transports.  While the Air Force gained ascendency over the fixed-winged CAS role, the Army retained all options for rotary-winged attack, assault, and heavy transport.

Under these arrangements, the Army retained the armed UH-1 gunships then employed in Vietnam.  The Army also proceeded with the Advanced Aerial Fire Support System (AAFSS), with the leading candidate being the Lockheed AH-56 Cheyenne.  Calls from field commanders prompted the Army to procure an interim AAFSS, which came to be the Bell AH-1 Cobra.  I’ve not seen such in writing, but the official designation of that helicopter, retaining the “1” of the Huey line, seemed a paper hedge against Air Force interference.  In the end, the AH-56 proved too much, too fast, and the Cobras became the Army’s attack helicopter until replaced by the AH-64 Apache.

AH-56 - Biggest Cost Overrun Until the Sgt. York!

The Air Force, now “stuck” with the CAS role in a war that required “down and dirty” CAS, found its supersonic fighters insufficient for the job.  Several interim types entered service to include the A-37 attack jet and the F-5A fighter, both tested by the Army in the search for CAS (other aircraft used included A/B-26 Invaders from World War II and A-1 Skyraiders from the Navy).  The Air Force’s CAS role breathed life into the Light Armed Reconnaissance Aircraft (LARA) which eventually produced the Rockwell OV-10 Bronco.  It also birthed the A-X requirement, issued in 1966, for a purpose built CAS aircraft to be flown by the Air Force in support of the Army.  After a fly-off competition in 1972, the Fairchild A-10 Thunderbolt entered production.

A-10 all Dressed Up

And that brings us right up to the current state – the Army with an excellent rotary-winged attack helicopter, but dependent upon the Air Force for fixed-wing CAS.  Only now the airframes have much more flight hours than anticipated and there is no replacement in sight.

Past, Present and Future of Tactical Radios – Part 5

Continuing from Part 4 – As this is a look at the evolution of radio systems at the very forward edge of the battlefield, I’ll cover the backpack radios in a bit more detail.

As mentioned in Part 4, the military began looking at practical ways to adapt transistors for combat radios – first issuing requirements in 1952.  In 1957, the Army tested a series of transistor based backpack radios, then designated XC-1 through 3.  These became the PRC-25, which the Army designated as “standard” in 1961.  (Go here for pictures of the PRC-25’s “guts.”  Also see more details on the PRC-25 Radios.)  Yet initially the Army purchased only limited quantities and only for operational test programs.  The PRC-25 was never meant to be issued in large numbers, as the Army sought to develop the “ultimate” or “perfect” radio instead of settling for a 90% solution (remember this, I’ll touch on it later!).  But regardless, as the war in Vietnam began to draw on the Army’s resources, warfighters demanded the “new” radios.

AN/PRC-25 - Left, base mount. Right, backpack

Initially, advisers and units sent to Vietnam used the old PRC-10 radios (whose issues and limitations I’ve discussed earlier).  By mid-1965, MACV commander General William Westmoreland requested two thousand PRC-25s for issue to troops entering theater.  Many historians have aptly highlighted the inadequacies of the old radios as the catalyst for this request.  However, recall a significant portion of those early build-up deployments were air-mobile formations.  The addition of the helicopter to the battlespace revived the old radio frequency band issue.  The architects of air-mobility at Fort Benning opted to put VRC-12 series radios in those early “Hueys” (typically AN/ARC-122 radio sets with two AN/VRC-46s installed).  So the troopers of the 1st Air Cavalry Division needed PRC-25s to best coordinate with their rotary winged rides.

These radios made an immediate impression on the warfighters, enabling a shift in tactics.  Unlike in previous wars where squad patrols might never travel farther than a thousand yards from the front lines for more than a night, fighting in Vietnam featured long-ranging, small-unit patrols.  The squad and platoons needed reliable, long-ranging backpack radio sets.  The PRC-25 fit the bill.  In a 14-pound package, the “prick” (infantrymen are apt to simplify nomenclature with a label they might better identify with) offered a five kilometer range from its standard backpack antenna.  The AT-892 “whip” or “tape” used layers of thin metal laid in a sandwich, held in place by rivets and bands.  The composition allowed the antenna great flexibility without compromising the electronic profile.

And other options extended the radio set’s range.  If the tactical situation permitted, radiomen could place larger profile antennas.  In particular the RC-292 ground-wave antenna extended the range of the backpack set out to around eight kilometers, if not more.

RC-292 Antenna

The down side of the RC-292, aside from the ground footprint required, was antenna tuning.  The elements, those metal “sticks” projecting out of the antenna head, required “cutting” lengths to match the desired frequency band.  Lower frequencies required more elements than the higher frequencies.  Such limited operational flexibility at times, requiring re-assembly of the antenna for a simple frequency change.

Another innovation that extended range in Vietnam was airborne retransmission.  The 173rd Airborne Brigade used this early and often.  I have not discussed retransmission (or retrans) in great detail, as it is more a communications “tactic” than direct change in the combat radios themselves.  Often misunderstood, and thus misused, retrans allows the rebroadcast of one radio network onto another.  Using the right equipment this might mean networks of the same or different frequency bands, wave forms, or even mediums.  Putting the retrans station in a helicopter effectively extended the range of the backpack radio to anything within radio line of sight of the helicopter, often 100 miles or more depending on type of radio sets in the helicopter.   Yes, retrans allowed senior level commanders to “reach down” to squads if needed.  But this also allowed squads to “reach up” to resources for much needed support.

The PRC-25 was for all practical purposes “grunt-proof.”  Communication failures in combat decreased. I can’t put it better than simply, the PRC-25 worked.   Attrition of trained radio operators often forced infantrymen into RTO roles.  With little to no training, the infantrymen did well.  This success circulated through the Army manpower system, and lead to the introduction of radio operations training to all personnel. (A nice primer to Vietnam-era radio operation is found on the Vietnam Research website.)

PRC-25 in Operation, note whip antenna and the old M-1 series Carbine!

Stories of the PRC-25 in action highlight the radio’s ease of use and reliability.  The most often cited vignette involved 1st Battalion, 27th Infantry (Wolfhounds), 25th Infantry Division during Operation Attleboro in 1966.  Pinned down, the battalion commander, Major Guy S. Melody had his operations sergeant, Sergeant First Class Ray Burdette, place an RC-292 against a tree.  The PRC-25, augmented by a retrans, became the only means of contacting the surrounded battalion.  Eventually Melody would direct eleven different companies in the fighting, coordinate fire support and close air support, and effectively defeat a substantial attack by the 9th NVA Division, all through that simple backpack radio link.

Perhaps an even better measure of the radio’s success, the Viet-Cong and North Vietnamese used captured examples in preference to radios supplied by Chinese and Russian sources.  By the closing stages of the conflict, both sides used PRC-25 (or updated PRC-77) radios for tactical communications.

But as good as the PRC-25 was, the tactical communications system still faced some problems.  First, the radio still used one vacuum tube in the RF output.   Second, the PRC-25 lacked support for electronic encryption called a “secure mode” (recall the VRC-12 series radios introduced that capability).  Third, the original battery used to supply power, the BA-386, was a short-life alkaline-cell type.  Fourth, the PRC-25, a platoon radio, was often pushed down to the squads due to the failure of the Army to find a replacement “handie-talkie,” taxing the resources of the squad and that of maintenance support.  Lastly, the PRC-25 (and VRC-12 series) still required a substantial maintenance/logistical support chain.

I will look at how the Army addressed those issues, as tactical communications evolved during and after the Vietnam War.