AEgis model Dutch AH-64D
In the late 1960s flying over Vietnam, they called it ‘the golden BB’. It was a random unlucky enemy shot that could hit your aircraft in just the wrong spot, or you. A golden BB was usually something to worry about when cruising along at a comfortable altitude, maybe at night, mostly out of range of aimed concentrated triple-A, (AAA, or Anti-Aircraft- Artillery).
It would be something you would never see coming, some Papa San, maybe given an obsolete rifle by Mr. Victor Charles, (the VC, Viet Cong), and told to come out of his hooch and shoot at the sound of aircraft, any aircraft.
The ubiquotous UH-1 Huey helicopter was a pretty tough bird, but it was designed before more modern survivability features such as control systems redundancy, kevlar, titanium cockpit armor, and fire suppresion technologies were required, or even existed. One rifle round, in an unlucky spot, could be enough to bring one down.
Most helicopter casualties in Vietnam though were not golden BBs but were inflicted closer to the ground, landing in a hot LZ, (landing zone under fire). Small arms, heavy machinegun fire, grenades, and even sometimes mortar fire could be brought to bear on the low and slow choppers, forced to fly in predictable paths.
The total number of helicopters destroyed in Vietnam was 5,086. 3,305 of those were Hueys. 10% of all combat and combat support fatalities were associated with helicopter operations.
US aircraft desigers leared a lot from these losses. The US Army attack helicopter that succeeded the Huey based gunships, is the AH-64 Apache, the latest version being the AH-64E Guadian.
AEgis has built several models of the AH-64, including the Dutch army version. The Apache has numerous advanced survivability features that make it much less susceptiple to small arms, heavy machinegun, and small cannon projectiles. Boeing claims the fuselage can survive 12.7mm (.50 cal) rounds, probably even 14.5mm, and that engine and rotor components can withstand 23mm cannon hits.
This is quite impressive component hardening compared to our old Huey. The 23mm round fired by the Russian designed ZU-23-2 is certainly considered a non-trivial cartridge in terms of kinetic potential in anyone’s truck bed.
But there is one weapon in the hands of our enemies that has a punch that no amount of flyable armor can withstand. It’s the Rocket Propelled Grenade, or RPG, most common in the form of the RPG-7.
The RPG-7 and its newer incarnations is a weapon system evolved from the WW2 German portable anti-tank ‘Panzerfäust’, one of Germany’s ‘wonder weapons’, to try and stem the tide of Soviet tanks flowing inevitably toward Berlin.
Both weapons use/used a shaped charge warhead that has a conic configuration to focus the explosion of the charge like a lens into a jet at 20,000 feet/second plasma that can burn though 3/4 of a meter of steel armor.
It’s an unguided weapon, and requires a skilled gunner to hit even a stationary target at more than a hundred meters or so. But it’s cheap, plentiful, and easy to operate and reload, even by unskilled troops. 50 years ago the North Vietnamese Army discovered that if you put enough of them in the air in the direction of low and slow helicopters, around an LZ, sooner or later one of these ‘To whom it may concern’ shots would eventually hit something hard enough to detonate the warhead, like a transmission, or an engine, or…….a fuel cell.
The US was reintroduced to the danger of the RPG vs helicopter in 1993, in Somalia, this time while operating in the labyrinthine urban trap of a third world city.
Two Blackhawks were downed, three more damaged. The battle to rescue and recover the crews cost 18 US deaths and 73 wounded.
The continuing US military involvement in Southwest Asia has seen numerous further incidents of RPGs hitting helicopters. One incident, in 2011 in Afghanistan, resulted in the greatest loss of life in a single crash of the conflict. 38 were killed, 31 Americans, when a CH-47 coming in to land, call sign ‘Extortion 17’ was hit by one of several RPGs fired, at night, from at least several hundred meters away. It struck the rear rotor and exploded, plunging the fuselage more than 100 feet down into an explosion and fire.
‘With a keen understanding of the propaganda value of downing Coalition helicopters, the Taliban single them out as targets. Classified reports, published by Wikileaks, teem with notes from pilots and crew of all types of military helicopters who saw RPG attacks throughout the war. According to one Army report, in the three months prior to the Juy Zarin raid, as many as 17 RPGs were fired at helicopters over Wardak and Logar provinces, a relatively small part of the country. And while all military helicopters carry countermeasures for guided missiles, nothing can interdict the dumb luck of an unguided RPG round sailing through the air. The vast majority miss. “Chance is still part of the battlefield,” says Brady. “For every one that gets lucky, there are hundreds, even thousands that zip by you.”’
Our scientists and engineers can, and have, developed incredible, almost magical technological advancements in lightweight armor, sophisticated jammers that cause guided missiles to miss, and energy absorbing fuselage structures that allow aircrew to survive ground impacts at G forces up to the limit of human survivability, but against a dumb ‘bomb on a rocket’, the ultimate ‘golden BB’, we may never have more defense than luck, and Divine Provenance…
In addition to its normal energy absorbing function, each shock strut has one time high impact absorbing feature: its shear rings are sheared and a rupture disc bursts causing a controlled collapse of the strut.
The core structure of each blade consists of five stainless steel arms, called spars, which are surrounded by a fiberglass skeleton. The trailing edge of each blade is covered with a sturdy graphite composite material, while the leading edge is made of titanium. The titanium is strong enough to withstand brushes with trees and other minor obstacles, which is helpful in “nap-of-the-earth” flying
The Apache is heavily armored on all sides. Some areas are also surrounded by Kevlar soft armor for extra protection. The cockpit is protected by layers of reinforced armor and bulletproof glass. According to Boeing, every part of the helicopter can survive 12.7-mm rounds, and vital engine and rotor components can withstand 23-mm fire.
Armored protection is placed around the two main fuel tank capacity of 1400 liters of fuel.
Interior of the hull coated with three layers of protection against bullets and other projectiles. The first layer is called ballistic foam consisting of glass between two layers of special foam. The next layer of defense is a special type of resin that is applied over ballistic foam. The resin fills all possible air pockets that could flare up in the event of a fire hit the tank. Then add a layer of Kevlar, triple coating encapsulates tank and belly full of Apaches.
Seats provide extra protection Kevlar. The seats are so integrated into the cabin to provide, together with the landing gear, crew protection in collisions of 37g that is targeted at a vertical speed of 12.8 m / s bulletproof glass on the flight deck thickness 4.5 cm, which can withstand a hit from grain 23 mm.
Pilot and co-pilot are protected from almost all directions except the angle of 45 degrees in front of and above them.
Lever to activate the small package of explosives which separate window and make a quick exit
Scott Booth Bio:
Scott Booth Bio: Often found mucking about with 3D content development for visual simulations, or occasionally small UAS simulation. Usually found in the company of: salty NCOs, (yeah, you Tony), pilots- all types, gun nuts, manned space flight advocates, old car/truck/jeep fans, Sci-Fi readers, military historians, genius software programmers who like corny jokes, rocket scientists, dark beer drinkers, type-A sales guys, and other related near-do-wells.
Experience – 30 years visual simulation content development, company co-owner-founder – CG2 1995-2004, Small UAS simulation, AEgis-Vampire, Raven operator license, class 11-008, 2011.
Visual recognition expert, aircraft, armor, ships, subs, small arms, amateur military historian and shade tree auto mechanic.