AIRCRAFT of HMM-365 and Marine Task Element, Vietnam (1964-65)
Sikorsky UH-34D Seahorse, also known as "the Dog", and "the HUS"
- Powerplant: One Wright R-1820-84B/D radial piston engine (1,525 hp)
- Main rotor diameter: 56 feet (17.07 meters)
- Length overall: 65 ft, 10 in. (20.06 meters)
- Weight, empty: 7,750 lbs. (3,515 kg)
- Height: 14 ft., 3.5 in. (4.36 meters)
- Maximum allowable weight: 14,000 lbs. (6,350 kg)
- Maximum level speed at sea level, at 13,000 lbs.: 106 knots (122 mph; 196 km/h)
- Maximum rate of climb at sea level, at above AUW: 1,100 ft (33 meter)/minute
- Service ceiling, at above AUW: 9,500 ft (2,900 meters)
- Range with max fuel, 10% reserve, at above AUW: 214 nm (247 miles; 400 km)
- Accomodations: 18 troops or 8 stretchers
- Armament: transport aircraft (slicks) carried two single-crew operated swivel-mounted 7.62mm NATO M-60 machineguns; gunships (stingers) carried two 18-rocket pods of 2.75-inch rockets, two fixed-mounted 7.62 NATO M-60 machineguns, and three single-crew operated swivel-mounted 7.62 NATO M-60 machineguns
Flying the UH-34D: The UH-34D was primitive by most helicopter standards even at this date (1972). The engine was a radial design with nine huge cylinders. At sea level it developed 1525 horsepower at 2800 RPM and 56.5 inches of manifold pressure. It was a basic stick and rudder aircraft with a hot rod engine. However, as a helicopter, it had a collective and a hand twist throttle, which made it mechanically more difficult to fly than an airplane. The controls are servo assisted, but any movement on any control, be it rudder, cyclic control stick, collective or throttle required a corresponding adjustment on the other controls. Veteran H-34 pilots learned to utilize the energy in the rotor system to their advantage in mountainous terrain. Failure to do so left many of these birds broke and burned in the rocks. RPM is the staff of life in a helicopter and in the H-34, you guarded it religiously. [Allen Cates, from The Air America Webpage]
Cessna 0-1B Bird Dog, formerly OE-1
- Powerplant: one 159-kW (213-hp) Continental O-470-11 flatsix piston engine
- Maximum speed: 130 mph (209 km/h)
- Range: 530 miles (853 km)
- Endurance: 4.9 hours
- Weight, empty: 1,614 lbs. (732 kg)
- Maximum take-off weight: 2,400 lbs. (1,089 kg)
- Wing Span: 36 ft. (10.97 meters)
- Length: 25 ft, 9 in. (7.85 meters)
- Height: 7 ft, 3.5 inches (2.22 meters)
- Armament: none (the pilot usually carried a .38 caliber revolver, and sometimes a carbine and some grenades)
Douglas C-117D Skytrain, formerly R4D, also commercial DC-3
- Powerplant: two 1,200-hp Pratt & Whitney R-1830-92 Twin Wasp 14-cylinder two-row radial piston engines
- Maximum speed: 230 mph (370 km/h)
- Range: 1,500 miles (2,414 km)
- Weight, empty: 18,200 lbs. (8,255 kg)
- Maximum take-off eight: 26,000 lbs. (11,793 kg)
- Wing span: 95 ft, 6 in. (29.11 meters)
- Length: 63 ft., 9 in. (19.43 meters)
- Height: 17 ft. (5.18 meters)
- Armament: none
As the termination of SHUFLY kept being postponed, conditions in Vietnam prompted a turn to the armed helicopter. Since 13 April 1963, Marine helicopters had been escorted by Army UH-1B gunships. Six aircraft from the Utility Tactical Company, permanently based in DANang and armed with four forward firing 7.62mm, M-60 machine guns and 16 2.75-inch aerial rockets (FFAR), escorted the UH-34s "on all troop carrying missions and on all missions into known V.C. infested areas"
By late summer 1964, even this escort was not sufficient protection. On 17 August, General Greene directed MLFDA and HMX-1 to begin work on an armament kit for the UH-34. Less than two weeks later the first test firing had been completed. The kit, or TK-1 (Temporary Kit-1) as it was known, consisted of two pods for rockets and two M-60 machine guns. The weapons were mounted on a platform bolted just above the landing gear struts. One pod, containing 18 2.75-inch rockets, was installed on each side of the helicopter. The machine guns were both on the right side above the rockets.
The entire installation, including 1,000 rounds of ammunition weighed just over 1,000 lbs. Generals Mangrum and Robertshaw, along with other representatives watched a demonstration of a flight firing on the TK-1 on 8 September. The conclusion was that the kit on a UH-34 "could adequately provide fire support similar to that presently available in Vietnam". The TK-1 was simple, readily installed modificationthat could be manufactured easily by most aircraft maintenance me. The Station Operations and Engineering Squadron (SOES) at Quantico was to fabricate sufficient numbers to ship to SHUFLY. The first six arrived in Vietnam early in November.
Initial testing by HMM-365, however, had to be temporarily suspended due to its commitment to flood relief during Typhoon "Joan". The squadron reported that the limited evaluation which had been accomplished before the 17th of the month indicated that there might be some unforeseen problems. By the middle of December all the kits had been installed and though more testing was required, "with proper crew training and utilization, the aircraft could perform the mission satisfactorily as armed escort and for fire suppression." Crew training was accelerated by the forced transition program which brought into the squadron pilots with previous experience in aerial gunnery. They were pressed into service as a nucleus of instructors.
The next three months of experience proved that the UH-34 had serious shortcomings as a gunship. The relatively slow speed of the helicopter, the inherent vulnerability of critical rotor systems, and the type of warfare being experienced, all made the UH-34 a lucrative target for the Viet Cong. In addition, the helicopter was hardly an ideal gun platform. To achieve the desired accuracy from the rockets and fixed machine guns, the aircraft had to be flown in perfectly balanced flight. The instability of a helicopter made this difficult under the best of circumstances. During violent maneuvers in turbulent air it was impossible.
By the end of April, MAG-16 reported that the TK-1 kits "have not proved effective in combat operation." The evaluation was based on the "bitter experience" that the UH-34 gunships accounted for only 15 percent of the flight time in Vietnam, but were taking 85 percent of the hits. A complicating factor was that the TK-1 installations further reduced the already limited payload of assault troops or cargo. The recommendation that no further kits be procured was adopted. [Wm. R. Fails, Marines and Helicopters, 1962-1973]
- TK-1 Fire Suppression Kit: a weapons system consisting of two 18-inch 2.75-inch rocket-firing pods. One of them (the starboard side), also had two M-60 machineguns afixed to it. The system was fired by either the pilot or copilot using remote firing controls from within the helicopter cockpit. The weapon system was fixed to fire uni-directional only (forward) and getting the rockets and guns to bear meant that the pilot had to point the entire helicopter at the target. The aiming devices were either a make-shift "O-ring" or a circle drawn by a grease pencil on the helicopter's windshield in front of the pilots.
- M-60 Machinegun: a general-purpose machine that was designed to replace the Browning .30 caliber light and heavy machineguns. Used by the squadron aboard the UH-34D, both as part of the TK-1 Fire Suppression Kit and as a single-crewed manually served weapon. The M-60s that were manually served were placed on swivel mounts at the ports (windows) and hatch (door) of the helicopter. A 100-round ammunition box could be attached to the reinforced feedtray to enable the weapon to be fired and fed without the necessity of an assistant gunner. The bipod was kept attached to the gun so that it could also be used as a ground weapon. The achievements of the HMM-365 gunners are legendary, accounting for the majority of the squadron kills. Stinger gunners would carry 5,000 to 10,000 rounds of ammunition per aircraft. This weapon fires the 7.62 NATO (.308 Winchester) round at a rate of 600 rounds per minute. It weighs 23.05 lbs. with the bipod and is 43.75 inches long with a 25.6-inch quick-interchange barrel.
MARINE CORPS AIRCRAFT
Used in Vietnam, 1964-1965
A-4D Douglas Skyhawk: attack aircraft; assigned to attack squadrons (VMA)
KC-130F Lockheed Hercules: transport/refueler turboprop aircraft; formerly designated GV-1; assigned to VMGR-152
F-4B McDonell Phantom: supersonic fighter/bomber; formerly designated F4H; assigned to fighter squadrons (VMF)
F-8B Chance Vought Crusader: supersonic fighter aircraft; formerly designated F8U; assigned to fighter squadrons (VMF)
RF-8B Chance Vought Crusader: unarmed photoreconnaissance supersonic aircraft; formerly designated F8U-1P; assigned to VMCJ-1
EF-10B Douglas Skyknight: electronic warfare subsonic jet aircraft; formerly designated F3D-2Q; assigned to VMCJ-1
CH-37C Deuce: heavy lift helicopter used in limited numbers in the latter months of 1965; formerly designated HR2S; assigned to headquarters and maintenance squadrons (H&MS)
UH-1E Bell Huey: light transport helicopter; assigned to observation squadrons (VMO)