This … is a howitzer, but never ever the guys who invented it imagined that it would
one day be shot … from the sky! Since the invention of aviation,
militaries have pushed the limits of airborne weaponry. In the First World War, pilots dropped
the first airborne bombs; in the Second World War, planes could drop 40-50 bombs in one flight;
and by the Vietnam War, planes were armed with everything from napalm to mini-guns.
But how one aircraft company was able to make the Howitzer fly,
and why the pilots of the Howitzer need to wear night vision goggles, is Not What You Think!
Over the course of the 20th century, the US Air Force developed its own concept of close
air support, creating doctrines that allowed for ground units to call in attack aircraft via radio.
These attacks consisted of one to two aircraft,
scrambled from airfields or carriers and armed with payloads specific to the
kind of target they were called in on, such as armor, personnel or structures.
Over time, two problems with this type of ground attack became obvious to the US Air Force.
When doing a bombing or strafing run, the effectiveness of the attack was limited
by its precision and duration, and while bombs could be guided to hit their target,
an aircraft could only do so many passes over the area before running out of munitions.
As the US Military continued to develop its tactics during the Vietnam War, it came to
the realization that a more continuous rate of fire was needed on all fronts.
At first, newly developed helicopters armed with door gunners were used, but their fuel capacity
limited the kind of duration the military needed, which is why by 1965, the US had
developed the first ever flying gunship, the AC-47, also known as “Puff, the Magic Dragon”.
The design was deceptively simple and cost effective,
since it only required the regular C-47, the Air Force’s most plentiful cargo plane at the time,
and three, 7.62mm miniguns, mounted on the left side of the plane.
Puff, the Magic Dragon, became massively successful for one
major reason: it could loiter over the battlefield for up to 3.5 hours,
providing continuous support to the troops on the ground as various targets were called in.
Its ability to fly in a circle meant that as long as the left side of the aircraft
was pointing at the target, it could fire on it, providing far more sustained damage to the enemy.
Despite the early success of Puff, the C-47 was limited in the number and arrangement
of guns that could be mounted to it due to the low wing profile of the airframe.
With the success of the AC-47, the Air Force continued to experiment
with cargo aircraft and side-mounted guns, and began developing the C-130,
the most advanced cargo plane the US had at the time, into a gunship just like the AC-47.
Due to its size, fuel efficiency, and aerial refueling capabilities,
the C-130 could fly further, faster, and longer than the C-47,
but above all else, it could carry five times the weight of weaponry compared to its predecessor.
The early versions of the AC-130 used four miniguns and four rotary cannons,
but within a year of its introduction,
Lockheed upgraded the aircraft with a “Surprise Package” to 20mm and 40mm cannons.
This version, the AC-130A was named “Spectre”, since it mostly came out at night like a ghost.
This reputation for nighttime activities has continued to the present day, since
flying at night protects the large, slow cargo plane from anti-aircraft
guns and allows it to loiter without interference from small-arms damage.
But even with the surprise packages adding more millimeters, It didn’t take long for
the US Air Force to realize they wanted even more… fire power from the AC-130, and in 1972,
the first 105mm howitzer was delivered to Vietnam for fitting to the AC-130 airframe.
Of all the weapons to arm a plane with, a howitzer is the most difficult. This is
because of the special design of howitzers,
which are actually the halfway point between traditional cannons and mortars.
See, cannons are meant to fire forward, with very little angle of elevation, such as the cannons on
tanks or anti-tank emplacements. Mortars, on the other hand, are intended to fire
at almost an upward angle, with just a slight enough angle for the shell to travel forward.
But howitzers, especially American-made ones, are meant to fire at angles between 40 and 90 degrees.
So how did the two most powerful aircraft companies in the world make this work?
As a joint venture between Lockheed and Boeing,
the AC-130 had unlimited resources to custom fit the M102 howitzer to its airframe.
First, they had to solve the two problems that all guns have, recoil and gas.
The recoil of a side mounted howitzer was no problem for the lifting power of the airframe,
although it still did push the airplane 6 feet in the opposite direction when fired.
But a large piece of equipment sliding back and
forth with the crew nearby was extremely dangerous.
To solve this, Boeing built a safety cage of multiple bars, painted yellow,
that prevent crew members from accidentally standing in the recoil path of the gun.
Second, the design of the C-130 cabin had been a sealed and pressurized cabin from the start,
which meant gas build up from the gun would be dangerous to the crew.
Here, Boeing opted to re-route the gas through the front of the howitzer,
which is why the M102s on the AC-130 have a distinct thick muzzle.
The addition of the M102 to the gunship now meant even more tactical applications for the aircraft,
since the howitzer could fire different shells depending on the mission, with everything from
high explosive rounds for convoy interdiction to flares for night time visualization.
With the challenges of mounting such a weapon to the aircraft solved,
Boeing now had to find a way to ensure the efficacy of all of the weapons systems on board.
Naturally, they packed the large cargo bay with fire control consoles and targeting computers.
known as the “Mission Operator Pallet” or MOP for short, uses a pair of joysticks,
much like a game controller, to zoom in and out and control where the gun is pointing.
Over time, improvements in software and sensor arrays have allowed the crew to engage two
separate targets over a half mile apart. This helps gunners hit their targets, but
how do pilots know where to keep the plane and its guns pointed, so they’re in the right direction?
Once a target has been identified, the pilot sets an optimal range that all of the
gunship’s weapons systems are effective at. Then the pilot engages in what is
known as a “pylon turn”, which is a tight, circular, flight pattern around the target.
Regardless of expensive technology, pilots have found a simpler solution:
to make sure the gunners hit their targets they use the same cheap
holographic sights that infantry and special forces use for their rifles.
By keeping the holographic sight pointed at the target, the pilot can adjust his
turn to the exact angle needed for the gunners to maintain their fire. Another
ingenious solution developed by AC-130 pilots is learning to fly with night vision goggles on.
The necessity for this skill comes from the fact that when the gunships fly their missions at
night, they must be completely blacked out, so as to not give any hint to their location in the air.
With all these capabilities, the AC-130 lineage of gunships has
seen continuous service since its introduction in the Vietnam war and
earned a reputation amongst the troops on the ground as their guardian angel.
However, despite the love and notoriety of the platform, it is not without its flaws.
For all its firepower, the AC-130 is still a cargo plane at heart,
and its large size and slow maneuverability leave it vulnerable to all types of anti-air fire,
which is why it is only used when total air superiority and ground suppression is assured.
But as technology develops, the concept of pure air superiority becomes less attainable.
Today, drones and missiles have progressed to a point where even if air superiority is achieved,
a large cargo plane in the sky is still an easy target.
With their low radar signatures and high speeds,
inexpensive drones could easily deliver an air-to-air missile against an AC-130.
Furthermore, the high speeds at which modern standoff missiles are fired may be too fast for
the crew to even be able to react, making the skies even deadlier for the gunship.
While the Air Force has invested in several laser technologies and
sensors to modernize the gunship even further and improve its survivability,
at a price of nearly $200 million a piece, is the cost and risk still worth it?
For now, yes. Since the US employs the AC-130 in unconventional anti-terrorism operations.
But if the AC-130 ever faces more advanced enemies, will it become a ghost of the past?