The Development of the Cobra
The AH-1G Cobra
The Army had tried to expand its air capability and had built up a modest fleet of small- and medium-sized fixed-wing transports, but shortly after the war in Vietnam began, it bad to relinquish most of this to the Air Force. Thus, if the Army was going to have any aircraft of its own, particularly those for attack missions, they would have to be helicopters. The manufacturers capable of developing such an aircraft, specifically designed for the Army's needs, were aware of the requirement and a number of them proposed attack helicopters.
Most of these manufacturers proposed entirely new helicopter models. The design, testing, and production of these, particularly of the critical drive system, engines, transmissions, connecting shafts, and rotors, would take much time. Thus, even under an accelerated schedule, any new aircraft proposed could not be ready for the operating units for several years, too late to meet the Army's requirements.
One company, Bell Helicopters, had an easy solution to the Army's problem. A proven drive system from the long-since-tested and operated UH-1 series could serve as the basis of a helicopter specifically designed for the airborne attack role. A different fuselage would he needed, but compared to designing or building an entirely new aircraft, the problem was minor, and such an aircraft could be put into production in a relatively short time. Bell decided to gamble, though not without some assurance of success, and built an attack aircraft without any firm orders for it. The first model was unveiled in September 1965. It was officially designated the UH-1H, but was more commonly called the Huey Cobra, or just simply "The Cobra."
On 11 March 1966, Bell announced that "after its development as a company project [the Cobra] has since been flown extensively by both company and military pilots in rigorous test and evaluation programs," and that "the U.S. Army . . . would order the high speed Bell UH-1H Huey Cobra, the world's first helicopter developed as an aerial weapons platform." The aircraft, "featuring functional streamlining, record-breaking speed and tremendous fire-power capabilities, was developed by Bell as a modified version of the Army's UH-1B Iroquois, which is now being used extensively throughout Vietnam," the company added. The new machine had demonstrated sustained speeds of 200 miles per hour in level flight during company tests. "The speed attainments have been halved by Bell engineers as a performance breakthrough for aircraft of pure helicopter design and are considerably better than the world's speed record for helicopters of the Huey-Cobra's weight class," Bell boasted. The speed record at the time for light helicopters was 180.1 mThes per hour set by the UH-1D in 1964.
Bell's Vice President for Military Contracts, Hans Weichsel, said that the Cobra "is not a new product, but a modified version of the UH-IB, which can be readily deployed directly from production to field units now equipped with the UH-1 series helicopters. Not only could testing be shortened, but "transition for pilots and mechanics will be simplified due to the similarity of dynamic systems and flying characteristics between the UH-1H and UH-IB." The new aircraft "retains the UH-IB dynamic components, including the Lycoming T-53-L-13 gas turbine engine. Utilizing proven components currently in the supply system," it was stated, "results in a highly reliable machine that can be easily maintained with maximum use of on-site parts."
It was difficult for an observer to believe that what they saw as a Cobra had anything but the most distant relationship to the UH-1 series." The new attack aircraft was a streamlined, extremely thin helicopter. Viewed from the front, the fuselage was only three feet-six inches wide as compared to over eight feet on the standard UH-1. The narrow profile, however, was effective in presenting any enemy with an exceedingly small target.
To accommodate the crew in such an aircraft, the cockpit was arranged so that the pilot sat directly behind and slightly above the front seat. From there, he could have sufficient visibility to maneuver the aircraft in almost any situation. The front seat, which had a slightly better view of the ground immediately to the front of the aircraft, was occupied by the gunner. He had a few of the control mechanisms available to the pilot, but was not a copilot in any conventional respect.
A careful observer would find similarities between the Cobra and its ancestors. At extreme length, the Cobra was less than one half inch shorter than the UH-1. There was also the familiar 44-foot diameter main rotor, and a tail rotor, which was but one inch larger than that of the previous models. Typical of the design, the new aircraft had no wheels and used skids instead.
Even though the fuselage was much smaller than the UH-1 series, the Cobra weighed more when empty - 5,517 pounds as compared to 4,734. Likewise, the maximum weight was also more - 8,620 to 3,500. The difference was mostly due to the armament, and there was no doubt that the Cobra was armed as an attack helicopter. Two short wings, slightly less than two feet long, protruded from the aircraft. On each of them there were two positions for installing gun and rocket pods and other armament. In addition, the aircraft could be fitted with several models of remote controlled turrets mounted in the "chin" of the fuselage. Depending on the particular model of turret, they could fire 7.62mm machine guns, 40mm grenades, or a combination of both. The pilot, gunner, and the vital parts of the aircraft were protected by armor.
The Army was delighted with the aircraft, and ordered it into full-scale production. On 29 August 1967, the first Cobras arrived in Vietnam. One week later the aircraft logged its first combat kill -an enemy sampan and crew. Within a year, Bell had delivered more than 350 Cobras to the Army.
Since the Cobra and the "Huey" were designed for such different roles, and, at least externally, appeared to be different aircraft, the designation UH-1H was confusing. It was subsequently changed to AH-1G (Attack Helicopter-1G).
The Marine Corps watched the development of the Cobra with interest. It requested that sufficient attack helicopters be procured to provide a squadron of 24, in each of the three active wings. In 1967, Brigadier General Earl E. Anderson reported on the results. At the time he was the Deputy Chief of Staff for Research and Development. General Anderson had flown helicopters in Korea with VMO-6 and had been the commanding officer of MAG-36 at Santa Ana during the Cuban missile crisis. He was the youngest active duty Marine ever promoted to general and, later, became the first Marine aviator to bold the rank of full general whihe on active duty when he was assigned as Assistant Commandant in April 1972.
In July 1967, he said "funding and production of the AH-IG for the Marine Corps have been approved by the Secretary of the Navy. We are now awaiting approval from OSD." General Anderson was destined to be disappointed, for only 38 aircraft were approved for FY 69. They were "designed to support 24 operating in South East Asia in FY 70 (2 VMOs with 12 AH-1 each).” “This program,” a report concluded, "is not in keeping with the 'Force in Readiness' concept."
Two weeks after General Chapman bad become Commandant, on 15 January 1968, General McCutcheon submitted the latest information on the Cobra program:
“Existing UH-lEs were modified to fulfill this requirement. However, in so doing, the availability of the UH-lE for performing the missions for which the aircraft was procured was degraded. WhThe the modified UH-lEs are now doing a creditable job, the AH-1 will provide greater speed and firepower and more flexibility in the performance of the armed helo mission. The AH-1 will also free the UH-ls for light helicopter utility mission, many of which are now neglected."
He concluded by assuring the Commandant that efforts would continue to have sufficient AH-1s approved, but for the present, the number of AH-1Gs remained at just 38. In February 1969, the first ones were delivered to the Marines at the Bell plant in Fort Worth, Texas. Since the total number of Cobras was so small, no postgraduate flight training program was established. Instead, the first five aircraft were loaned to the Army "as training vehicles for instructing Marine pilots." Three months later, the first Marine Cobra pilots graduated from Hunter Army Airfield. They were Majors Jimmie A. Creech, James W. Rider, Ronald J. Thrash, and John L. "Jack" Pipa. Out of a class of 39 pilots, the four Marines graduated in class standing as one, two, three, and four respectively."'
By the end of June, 17 AH-1Gs had been received. In addition to the five on loan to the Army, two had been sent into a research and development program to study further the potential of such an attack helicopter. The rest had been sent directly to Vietnam, the first shipment of four aircraft arriving 10 April. They were assigned to Lieutenant Colonel Clark S. Morris's VMO-2. At the time, the squadron had a complement of 8 UH-1Es and 23 OV-10s, in addition to the new Cobras. After a week of test and orientation flights, "the first Marine Corps AH-IG in Vietnam went operational 18 April 1969" by flying escort for a medical evacuation flight. The pilot was Major Donald E. P. Miller with First Lieutenant Tommy L. James as the gunner in the front seat.
In the next few months the Cobras brought some surprises to the enemy who were more acquainted with the UH-IE gunship or the machine guns of the CH-46 and CH-53. One incident was related by Colonel Kenneth S. Foley. He wrote:
On 11 July a report was submitted evaluating the AH-IG in its first months of combat. The conclusions were very favorable. When compared with the armed UH-lE the new attack aircraft was called "a far superior weapons platform precluding the need to fly rocket and gun runs below 1000 feet for the required accuracy." The aircraft "has a much improved armament system that provides greater firepower and flexibility ... and permits steeper dive angles ... providing greater accuracy." The cruise speed was such that it was "compatible with that of transport helicopters, allowing the AH-1G the capacity to lead troop transport helos into the objective area and be able to loiter overhead for an entire lift." The biggest problem was that most of the spare parts that were not the same as those for the UH-1E had to be ordered from the Army, and delays had been encountered.
By December, VMO-2, now commanded by Lieutenant Colonel Stanley A. Challgren, had its full authorization of 24 Cobras. Then, on 16 December, in a reorganization which affected all units in Vietnam equipped with the AH-1G, UH-lE, and OV-10As, the aircraft were transferred to HML-367. The commanding officer was Lieutenant Colonel Warren G. Cretney who later would serve as liaison officer with the Army during the time it was training Marine Corps helicopter pilots.
Slow delivery of parts, however, was not the only difficulty with the AH-IG. It was an aircraft designed for the Army. Like the UH-1B/D, which had led to the Marine UH-lE, the Cobra had no rotor brake and thus was only marginally suitable for use on board ships. It also had Army avionics, which, though satisfactory, created additional supply problems. The Marine Corps preferred a different chin turret. It wanted one which had heavier 20 millimeter guns rather than the 7.62mm installed in the Army version. Most important, the Marine Corps felt that the helicopter should have two engines. From the very start of the program it had been pushing for such a twin-engined Cobra. General Anderson had said that such a version "which the Marine Corps desires, offers a substantial increase in relative combat power and reliability over the present [AH-IG]. Its gun platform, stability, cruise, dive, and maximum allowable speeds are marked improvements. “Moreover,” he continued, “it can deliver twice the ammunition and operate in the objective area twice as long.”
Colonel, later Lieutenant General, Thomas H. Miller was the Head, Air Weapons Systems Branch, Deputy Chief of Staff/Air during the time the Marine Corps was attempting to win approval for the "twin" Cobra. A highly decorated combat pilot, he had won 18 medals in World War II and Korea, and four Distinguished Flying Crosses', one of which was for setting the world's speed record of 1,216.78 mThes per hour in an F4B "Phantom" on 5 September 1959. He summed up the arguments. "Justification for the twin-engine power plant is based on four major factors: improved crew safety, increased reliability in mission performance, increased payload, and growth potential." He went on to point out the "Records of the Naval Aviation Safety Center indicate that during 1956-1967, 17 USN/ USMC UH-1 [type] helicopters were lost or damaged in combat or operational mishaps directly attributed to the failure or malfunction of its single engine." The result, he emphasized, was eight fatalities and four major and 20 minor injuries.
Another factor which the Army did not have, to face, was that the Marine Corps mission was based on amphibious landings. At sea, in an aircraft with only one engine, a malfunction almost invariably led to the loss of the helicopter and often some of the crew. Recent experience with the twin-powered CH-53 and CH-46 had proved that with two engines, if one malfunctioned, not only could the crew be saved, but often the aircraft, too. Even the mighty "Deuce' had made safe landings on board a ship with one engine not operating, though the event was usually the highlight of excitement for any amphibious force. Over land, it was pointed out, "whThe it is true that a single engine helicopter can auto-rotate a power-off, controlled descent to a landing in the event of power failure, aircraft losses still occur when the terrain is unfavorable to a landing." Not only that, "in some cases missions can and have been completed on the remaining engine when a single power loss has occurred."
There were other reasons, but they all added up to the fact that the Marine Corps required Cobras with two engines and not the Army single-engined version. The Marine Corps model was to be designated the AH-1J. Approval turned out to be more lengthy and difficult than anyone had anticipated. The Marine Corps found itself having to thread its way through a thicket of opposition to the "twin" Cobra. By early 1968 it was apparent that, even if approval could be gained, the additional engineering, design, and testing of the improved model would delay its introduction into combat. Thus General McCutcheon agreed to accept the single-engine Army version and gained OSD approval "but only until the end of the war." He added that “simultaneously with our fight to get Cobras, we have been fighting to get them with two engines…”
“This has been quite a battle in itself both with SecNav, OSD, and the Congress.” Part of the problem, he continued, was that OSD "requested that we offer both equal effectiveness a well as equal cost trade offs of fixed-wing aircraft in order to retain the armed halos." The staff of OSD remained unconvinced that, in the Marine Corps, armed helicopter, and fixed-wing attack aircraft complemented, not competed with each other. General McCutcheon concluded that "We are challenging the validity of the equal effectiveness concept, but we are examining ways to get an equal cast trade off." The old dictum that for every additional helicopter, a fixed-wing aircraft had to be deleted, was still wry much in effect.
The FY 69 Defense Budget proposed the procurement of 38 AH-1Js. These aircraft were not exactly what the Marine Corps had hoped for. They did have the rotor brake, Navy avionics, and the desired chin turret, but they did not have two engines. Though such a "power pack" was available, the cost of buying enough for such a limited number of aircraft proved to be too high. The AH-lJs requested would still be equipped with a single Lycoming T-53 engine.
In the early spring of 1968 the Marine Corps, received a boost in its efforts to bring twin Cobras from an unexpected - though not necessarily appreciated - source: the North Vietnamese Army. During the annual holidays of "Tet," it launched an all-out attack on the allied forces. In the resulting battles, the UH-1E armed helicopters played a large role in defeating the enemy and inflicting heavy casualties on him. The aircraft had ample opportunity to demonstrate their effectiveness. It was not without cost, however. A number had been hit by county fire and either severely damaged or destroyed.
The Marine Corps was quick to point out the need not only for replacements of the aircraft lost, but for more Cobras to be readied for the war. It also emphasized that as long additional aircraft were required, they should be twin- engined. Such a "powerpack" was now available at a suitable cost from Pratt and Whitney of Canada.
The Secretary of Defense, in April, asked Congress for permission to take funds from less urgent programs; and divert them to the "Twin" Cobra, which was now also known as; the Sea Cobra. Not only was the Marine Corps finally to have its Cobra with two engines, the Secretary of Defense increased the number to 49.
During hearings on the new program before the Senate and House Armed Services and Appropriations Committees, a new controversy broke cut. It centered around the use of the Canadian-built, twin-engine, pack. 0n 9 April 1968, the Chairman of the House Armed Services Committee, L. Mendel Rivers, wrote Secretary McNamara voicing his concern over not buying an American-built engine. Congressman Rivers was assured that there would be a competition prior to selecting the engines for the AH-1J. The Naval Air Systems Command sent out requests for proposals an 3 July to all eligible manufacturers, including those in Canada. A month later, at the deadline, only two had answered. They were United Aircraft of Canada, which was the parent company of Pratt and Whitney who had made the original offer, and Continental Aviation and Engineering Corporation, an American concern. Both engines were suitable, but United Aircraft's entry already was in production and had been thoroughly tested. The Continental engine would not be available until sometime in the future. The United Aircraft "power pack" was selected and the contract awarded.
On 14 October 1969, Bell Helicopter unveiled the first AH-1J twin-engined Sea Cobra. The ceremony, and a conference on details of delivery and design, was attended by a group of Marine officers including Brigadier General V. A. Armstrong. He had been designated a helicopter pilot 25 August 1949 and was the 28th Marine to be officially qualified in rotary wing aircraft. He had commanded HMR-161 in Korea and he had participated in some of the earliest helicopter combat operations. He had also served as commanding officer of HMX-1 in 1960 and MAG-36 in Vietnam in 1966. In World War 11, Korea, and Vietnam he had been awarded a Silver Star, seven Distinguished Flying Crosses, and 12 Air Medals, among numerous other decorations. At the Bell plant, General Armstrong was accompanied by Colonel Edwin H. Finlayson, Head, Weapons Group, at HQMC, and Colonel Henry ("Hank") Hart, program manager for assault helicopters at Naval Air Systems Command.
The helicopter they saw was almost exactly the one the Marine Corps had wanted. The chin turret was an XM-197 model equipped with a three-barrel 20-millimeter gun firing up to 750 rounds per minute. Also available for mounting on the stub wings were an XM-18 self-contained 7.62mm "minigun" pod and seven-tube XM-157 and 19-tube XM-159 serial rocket pods. The aircraft had a rotor brake for shipboard operations, standard Navy avionics and most important, twin engines.
When the Marine Corps had purchased the Army version of the Cobra, no testing had been required prior to introducing the aircraft into combat. The modifications necessary to create the AH-lJ, however, were sufficiently extensive that the first four aircraft were delivered to Patuxent River for Board of Inspection and Survey (BIS) trials in July 1970. The next seven arrived in September at New River "to start crew and maintenance training." 30 The aircraft were assigned -to Lieutenant Colonel Robert D. Myer's VMO-1. There had not been time to install all the parts of the new armament system in the first 11 aircraft, so eventually all were returned to Bell for further modifications.
As soon as pilots and crews could be trained, and all the required changes installed on aircraft at the plant, four Sea Cobras were to be shipped to Vietnam for an evaluation in combat. This test was to be conducted under the supervision of Colonel Paul W. (Tiny) Niesen. On 12 February 1971 he, eight other officers, and 23 enlisted Marines departed the United States for Marble Mountain. The same day, the four AH-1Js left in Air Force turboprop C-133 cargo aircraft.
The crews arrived 16 February and the aircraft two days later. The evaluation unit was assigned to Lieutenant Colonel Clifford E. Reese's HML-367. The first combat test of the new twin-engined Cobra came four days after the aircraft had been unloaded. Colonel Niesen and Lieutenant Colonel Reese joined the Army-version aircraft while supporting transport helicopters around a hostile landing zone.
For the next two months, the small detachment kept its four aircraft busy. By 28 April, when the evaluation was completed and the aircraft shipped from Vietnam, they had flown a total of 614 hours, shot 14,950 rounds of 7.62mm ammunition, 72,945 of 20mm, and 2,842 rockets in addition to several other items of ordnance. The Commandant received a report, which summarized that "the combat evaluation determined that the AH-1J provides a significantly greater effectiveness in firepower over the AH-1G."
There were two basic ways to load the AH-lJ, depending on the type of targets which could be expected and the amount of fuel required for the mission. A "light" load of 1,475 pounds consisted of a full amount of 20-millimeter ammunition, 14 2.75-inch rockets, and either forward firing gun pods or other light ordnance. For the "heavy" version, 2,400 pounds of armament were included. A total of 76 rockets and 300 rounds of 20-millimeter ammunition shells for the chin turret made up this load. The Sea Cobra was capable of speeds up to 155 knots in level flight and could dive at 190 knots. Even with one engine malfunctioning at the maximum weight of the aircraft, it could maintain flight at 2,000 feet.
Coincidentally, on the same day that Colonel Niesen and Lieutenant Colonel Reese began combat operations with the Sea Cobra in Vietnam, at New River the first helicopter attack squadron (HMA) began to form. An "activation cadre" with Lieutenant Colonel Lloyd W. Smith, Jr., as officer-in-charge became a part of MAG-26. Initially, whThe waiting for its aircraft, the unit was assigned UH-1Es. On 7 April, five AH-1Js arrived from the Bell factory. By the end of June the "cadre" had received 23 more Cobras."
At ceremonies on 1 July, the "cadre" was disbanded and HMA-269 became the first of three helicopter attack squadrons in the active forces and one in the reserves. Armed helicopters had come a long way since the first efforts to give weapons to the crew members of the SHUFLY squadrons in early 1962.
“Experience in Vietnam has clearly shown that armed helicopters are an essential member of the fire support team. Due to continued circumstances of weather and terrain the armed helicopter has proven to be an absolute necessity in the delivery of close-in fire suppression support during vertical assault operations.”
“With [Cobras] covering, a Marine rifle company was moving out cautiously. Shots came from around the bend and the [Cobras] covered the area with fire. When the Marines got there, five Viet Cong were horizontal; four dead and one wounded. The wounded VC was shouting and banging his fists into the dust. One company commander asked the interpreter what all the shouting was about. "He's apparently the squad leader," the interpreter replied. "He's yelling, 'if I told them once I told them a thousand times-don't shoot at that kind of helicopter!"
The Marine Influence