THE BIRTH OF THE BUSHRANGER.
Printed with permission from Carla Evans great book ( the third in the series)WINGS OF SUPPORT
ISBN 0 646 347853
These books can be purchased by contacting Carla at
68 Boonderabbi Drive Cliffton Springs --Phone 03 5251 3440
It is said that necessity is the mother of invention. The Australian helicopter gunship had a modest and unusual conception. Normally our soldiers would be delivered to an operation zone by helicopter and when the operation had been completed, they would be picked up from a pre-determined point. The helicopter insertions and extraction's were usually done by 9 Squadron, based in Vung Tau, though some were done by US Army units. Sometimes the soldiers found themselves pinned down by close enemy fire and asked for air power to help them out.

The 9 Squadron helicopter, with the call sign of ALBATROSS was a UH-lD or UH- 1 H Iroquois helicopter equipped with an M60 machine gun mounted on a pintle post at each side door and mainly used for light defence during these delicate operations. Calls for air power or fire support were mainly answered by the US Army Aviation units quite willingly and with massive amounts of fire power but with the accuracy of a shovel lull of wheat thrown at a barn door.

Picture the scene: a handful of our infantrymen spending a night or two at Vung Tau sitting with some 9 Squadron airmen complaining about the RAAF not giving fire support where and when needed. Over a can or two or three, an idea is born. A small group of Australian airmen said, "Why don't we build a gunship, and why can't we build a better one than the Yanks?"

While formal requests to Australia were initiated this innovative band of airmen lost no time to begin their plan. After a few visits to the US Army helicopter graveyard and to the US Army store and armed with a handsome quantity of the legal tender of the day (x cartons of VB, accompanied by much lively negotiation) all the necessary equipment was procured: gun mounts, rocket pod mounts, gun sights, ammunition bins and booster motors, 7.62mrn mini-guns and a couple of 7 tube rocket pods. Now it all had to be put together.

The American Iroquois gunships had major problems with accuracy, weight and balance. The Australians fixed the accuracy problem by dispensing with all the hydraulics in the gun and rocket mounts. The US gunships employed a system where a gun sight, pivoted from the aircraft ceiling frame, would hydraulically drive the gun or rocket mount to 150 from centre in any direction. Imagine what a little hydraulic slack did for the cone of fire when a vibrating mini-gun was firing 70 to 100 rounds per second! So the 9 Squadron team simply welded all the weapon mounts to make them solid mounts. Then the gun sight was latched into a rigid mounting from the aircraft ceiling frame and a rigid weapons platform was formed. If the pilot wished to shift the point of aim, he simply pointed the aircraft, just as he would an old fighter aircraft. Then to remedy the weight and balance problem, the gun mounts were mounted on the forward hard point just behind the pilot's door: the rocket pod mounts were mounted on the aft hard point, just forward of the transmission well. On the US gunships, the aft hard point carried both the gun and rocket mounts.

A total of 30 x 300 round ammunition containers were mounted across the floor, two rows feeding each gun, with a booster motor to assist the feed of ammunition from the numerous bins through the flexi-chutes to the guns. A duel M60 machine gun pintle post, with 1000 rounds of ammunition per gun, was mounted on each side for the Crewman and the Gunner. This completed the hardware conversion. The electrical content of the modification included all the additional circuitry, looming, circuit-breakers, rocket stepper switches and a three second cycle control for the mini-gun circuit. Through a choice of gear drives, a mini-gun firing rate of 2000, 4000 or 6000 rounds per minute could be employed. The 9 Squadron chose the 4000 rate, giving a very effective fire power without excessive use of ordnance and to reduce the risk of overheated barrels. During the configuration change, the cargo hook and the rescue hoist were removed prior to the installation of weaponry.

Well the gunship was duly loaded, flown, and test fired by the unit's pilots and weapons officers. The pilots liked it, the ground crews found it simple and functional and as a weapons platform it was deadly accurate.

Now that it flew, the squadron sought approval to make the modification official. Yes, you guessed it; approval was declined on the grounds of insufficient funds at the time! Rather than throw the towel in, the squadron waited a little, then using a clever tactic, sought approval to modify a second aircraft to complement the first. This time approval was granted.

Before too long the Australian Iroquois gunships with the call sign of Bushranger 71 and Bushranger 72 were contributing to army ground support with effectiveness not seen before. Stories began to abound complimenting its accuracy and effectiveness. In its early days, the gunship had a few technical teething problems. There were some unexpected multiple rocket firings resulting in a loss of accuracy and some early mini-gun stoppages on occasions all of which were a little embarrassing. However, with dedicated attention to detail and fault diagnosis by the unit's electrical and armament airmen, maintenance practices were both amended and improved. It was not unusual for this newly modified air to ground attack aircraft to group an entire three second burst of mini-gun (approximately 200 rounds per gun) into a target of less than thirty feet in diameter if required. The aircrew became polished marksmen with their new weapon. Even the rockets 2.75 in with I 71b warheads were being fired with amazing accuracy.

It was found that the Iroquois gunship could give very close support in a number of ways, including an armed cover during an insertion or extraction of troops, but its most effective role was the systematic attack against a concentrated stronghold while friendly troops were nearby. For example, while supporting our troops in the northern slopes of the Long Hai Hills, enemy fire was coming from inside several caves on the same slopes as our men were climbing. With uncanny accuracy, the gunships were able to deliver both mini-gun fire and rockets inside several of the caves which had an opening smaller than the height of a man.

After the gunships had been proven, it was good to see that a small selection of 9 Squadron airmen from the electrical and armament trades, plus a couple of the weapons officers were to receive well deserved commendations for their dedication and innovation.

The Iroquois gunship was a simple aircraft for maintenance purposes. The weapons systems were operated by a 28V DC system and the gun stoppages were reduced to an acceptably low level considering the enormous amount of ordnance fired. An important maintenance factor was the harmonisation of the weapons system to the aircraft and to the gunsights. This was checked upon every gunship build up and at frequent intervals as part of aircraft servicing. The big price paid by the gunship in maintenance was the enormous burden placed upon the engine, transmission main rotor head assembly and the aircraft frame, due to the weight carried even before the crew of four, calculated weight of 200 pounds each with their bullet proof vests, were on board.

This meant that at take-off the aircraft was about 11% over maximum weight. However, the Iroquois was a hardy beast and with meticulous maintenance and some very professional flying skills it survived well.

In time, there were four approved operational gunships in service with one spare kit of hardware. In addition there were numerous mini-guns, feeders and other sundry spares, all purchased with the legal tender of the day. This was later to be a slight embarrassment to RAAF accounting when, on the squadron's repatriation to Amberley, the stocks of mini-guns, M60 machine guns, rocket pods and many other spares were far in excess of that believed to be held!

During its time of operation the gunship had one significant disadvantage: it was still a slow process to hand load the 9000 rounds of ammunition into the four rows of containers, feed the crossover booster motors and then arm each gun. If, for example, a hot rearm was engaged with the aircraft engine running with the co-pilot at his post, a total rearm could still take some 12 to 18 valuable minutes. This became a vital issue when all four gunships were involved in a heavy offensive as each gunship was able to expend its entire load of ordnance and most of its fuel in 45 to 55 minutes. This meant that Operations were asking the squadron to rearm and refuel four gunships in this period of time. Considering one rearm of 12 to 18 minutes, plus a refuel of five to six minutes, Operations were asking a tall order indeed.

In mid 1971, the resident Armament Officer developed the Payne Hopper Bin. This large bin was constructed by modifying two existing US ammunition storage bins and was about 30 cubic inches, with a pyramid top section. Using the spare build up kit, a gunship was built with the new hopper bins, one feeding each gun. This meant that spare ammunition bins could be pre-loaded with 4500 rounds each at the forward arming pad at Nui Dat while the gunship was flying. On arrival, the gunship's empty ammunition bins would be removed and full ones installed and connected.

The day arrived for the first official test. The resident B flight commander, who had the alias of Boldfinger, was challenged by the Armament Officer that a complete and total rearm could be achieved safely in five minutes. The gunship arrived at the rearm point and stopwatches were punched. The side gunner's bins, the smoke generators and even the pilot's 9 mm pistol were empty! The five man rearm party was well prepared. While the co-pilot was holding the aircraft controls, they worked like poetry in motion. New bins and side bins replaced old ones, guns armed, and rockets loaded, smoke generators and the pilot's magazines were all replaced. Total time 4 minutes 50 seconds! Not bad for an ordnance load of 9000 rounds of 7.62 mm mini ammunition, 4000 rounds of 7.62 tracer ammunition for side gunners, 14 x 2.75 inch rockets and 10 smoke grenades. The aircraft then went to be refueled, another 4 minutes 30 seconds, making at total ground time of 9 minutes 20 seconds.

In less than eight weeks, all gunships were modified to the new Hopper Bin configuration. The effect upon hot scrambles and hot rearms was amazing. The forward rearm party was now able to rearm and replenish gunships as rapidly as they could rotate from target to base and back to target again.

As an example, in October 1971, after Bushranger 71 and 72 were scrambled to an offensive at about 1400 hours, within the first hour Bushranger 73 and 74 were scrambled as well. So from about 1450 hours to nearly 1800 hours, the four gunships were rotated through the re-arm pad. At the end of the offensive, a stock -take revealed a usage of nearly 108,000 rounds of 7.62 ammunition and over 160 rockets.

In the squadron's latter days in Vietnam, it became an unofficial custom to greet a new Australian Regiment with a fire power display, always a popular event. One involved the use of the body-shell of a VW Kombi as the target with an imaginary force as A, B and C platoons in a horseshoe shape some 50 feet either side and some 80 feet behind the target. The US Army contribution involved Hueys, Cobras, Broncos and UH- I H Gunships. A massive amount of fire power was dispensed with the target receiving a large number of hits. But 60 per cent of both A and B platoons plus 30 per cent of C platoon were wiped out. Then the two 9 Squadron gunships began their offensive pattern just like a fighter aircraft pattern. All the mini-guns' fire was contained within a 12 feet radius of the Kombi and all the rockets were within a 20 foot radius, with three or four direct hits. Very impressive!

Today the helicopter gunship has become a very highly complex aircraft using anti tank missiles, laser guided gunnery systems. While the original concept was from the US Army, it took a group of ordinary Australian airmen to transform this original primitive machine into a very accurate and very offensive weapons platform. One senior gunship pilot who received decorations in Korea, referred to the Australian Iroquois gunship as the best armament system he had seen since the Mustang. Some compliment.

John Clarkson Sgt. Armourer Ret'd RAAF.

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