Taking a Flight in the Bell 47

Simulators

[Image courtesy of Patrick Chovanec]

Today in Microsoft Flight Simulator 2020, I’m in Korea to fly the Bell 47, the iconic chopper from the TV show M*A*S*H and the first helicopter to be certified for civilian use.

The Bell 47 was produced by Bell Aircraft, founded by Larry Bell in 1935. Bell was known for producing highly innovative if not necessarily successful airplanes during World War II, most notably the tricycle-gear P-39 Airacobra fighter.

But the story of the first Bell helicopter begins in 1927, when a man named Arthur Young graduated from Princeton University with a degree in mathematics. Drawn to philosophy, Young wanted to tie his more esoteric interests to the solution of elusive practical problems, and the one that intrigued him most was the helicopter. At that time, the development of helicopters was a field full of eccentrics, and Young fit the profile of the lone oddball genius.

At his family’s farm outside of Philadelphia, Young spent 12 years conducting private experiments with model helicopters until he could reliably get them to fly. In 1941, he took his models to Bell Aircraft in Buffalo, New York, and the company agreed to work with him in developing full-size prototypes. Over the next few years, the small engineering team led by Young developed a helicopter, the Model 30, capable of controlled flight.

It was not the first helicopter to be developed. The Germans created a number of prototypes during the war. In 1943 Igor Sikorsky sold the R-4 helicopter to the U.S. Army, which saw limited search-and-rescue operations in the Burma Theater. However, improvements to Young’s Model 30 by late 1945 gave rise to the Model 47, a product Bell Aircraft viewed as marketable. One of the first customers was the U.S. Army, which designated it as the H-13 Sioux.

It’s the winter of 1952, and this H-13 is parked in the Haean Basin, an oval-shaped valley just south of today’s DMZ between North and South Korea—dubbed the “Punchbowl” by American troops. It was close to some of the toughest fighting late in the Korean War, including battles at Heartbreak Ridge and Bloody Ridge. As a result, it was home to the 8209th Mobile Army Surgical Hospital (MASH), one of several units on which the fictional “4077th MASH” of TV fame was based. The unit was equipped with Bell 47 (H-13) helicopters, which were famously featured in the opening credits of the long-running comedy-drama.

I’ll talk about MASH units, and the 8209th in particular, in a bit. First, let’s look at the tricky, bug-like aircraft that became their most recognizable symbol, the Bell 47. The fuselage of the Bell 47 is 31 feet, 7 inches from cockpit windshield to tail. The span of the main rotor is 37 feet, 2 inches. The helicopter’s height, to the top of its rotor mast, is 9 feet, 3 inches. The construction is bare bones, nothing fancy. The cockpit is made of sheet metal, with a plexiglass bubble windshield, and the tail is composed of exposed steel tubes. The Bell 47 has an empty weight of 1,893 pounds, about the same as a Volkswagen Beetle.

The Bell 47’s fuel tanks varied by model, but the two perched here each hold 30.5 gallons for a maximum range of 214 nm (246 sm or 396 kilometers). This is a Bell 47G, so the engine is a single Lycoming 6-cylinder, air-cooled piston producing 280 hp that is also used in some versions of the Beechcraft V-Tail Bonanza. Earlier Bell 47s used a less-powerful Franklin piston engine. The same engine drives both the main and tail rotor, via a cylinder-shaped transmission gearbox above the engine.

To understand what both rotors do, I need to explain the controls in the cockpit. Unlike most later helicopters, the primary pilot of the Bell 47 sits on the left. To the pilot’s left is the collective. It looks like the lift-handle parking brake in some cars. Raising it increases the pitch of all the main rotor blades the entire way around, increasing lift. The collective also has a twist grip controlling the throttle. Increasing rotor pitch also increases drag, which must be compensated by increasing throttle to maintain a constant target rpm (the green area on the dual tachometer for engine and rotor revolutions, at the upper left). Note that on a helicopter, you do not alter lift by making the main rotor spin faster or slower. You alter lift by changing the pitch of the blades while making sure they turn at a constant, safe speed.

In front of each seat is a cyclic, which looks like the control stick in an airplane. Moving it adjusts the pitch of the main rotor blades through one part of their rotation, tilting the helicopter in that direction. Inputs from the collective and cyclic are conveyed through the silver-colored swashplate near the base of the main rotor.

In the Bell 47, changes to blade pitch (“feathering”) operate through a stabilizer bar, a device invented by Young. It consists of two shorter rods that extend just below and perpendicular to the main rotor blades. When the stabilizer bar rotates, it acts like a gyroscope that wants to keep spinning in its current plane. This tends to cushion any new tilt to either the rotor blades or fuselage, to maintain stable flight, and remained a feature on later Bell helicopters, including the “Huey.”

The rotor head itself is semi-rigid, meaning it can teeter to either side. This allows the rotor blades to automatically “flap” up or down as needed to provide even lift. If the blades couldn’t flap, when the helicopter moves forward, the advancing blade on the right would cut through the oncoming airflow faster than the retreating blade on the right, generating uneven lift and causing the helicopter to tumble. The main rotor blades themselves were originally made of wood covered in fabric and had an unlimited lifespan because they did not suffer the same strains and fatigue as metal rotors.

The rotation of the main rotor blades creates torque, which makes the fuselage want to rotate in the opposite direction (clockwise to the right). The tail rotor is needed to offset this. Foot pedals on the floor of the cockpit control the pitch of the tail rotor blades, altering their thrust in one direction or the other. This allows the pilot to keep the helicopter pointing forward or rotate it toward whatever direction he chooses.

In the tail, wires link the pedals to the tail rotor head alongside the shaft from the engine powering the tail rotor. When the wires reach the tail rotor head, they work a mechanism that changes the pitch of the blades, and therefore their thrust, in either direction.

Near the tail, there is also a piece of sheet metal that acts like a tailfin. When the helicopter is moving forward, it helps keep the nose pointed in the direction of travel with less pedal input. The Bell 47 also has small horizontal tailplanes, like tiny wings. The airflow over them also tends to keep the helicopter more stable (stopping it from pitching up or down) in forward flight.

In addition to its own weight, the Bell 47 can lift just more than 1,000 pounds. That’s just about enough for the pilot and copilot, fuel, and two stretchers to rescue wounded from the battlefield that are placed over the landing skids.

The magneto switch to start the engine is on the top right. The gauge to its left shows the temperature in the carburetor. The black knob adds carburetor heat to prevent the moisture in the fast-moving air entering the engine from freezing. The red knob adjusts fuel mixture for altitude. The radio is on top. On the right side are my flight instruments. From top to bottom, they are: horizontal airspeed indicator (top), altimeter (showing elevation of not quite 1,500 feet above sea level), and vertical speed indicator. My heading indicator is attached to the frame of my bubble windshield off to my left.

Now that I’ve started the engine, to the left you can see the tachometer showing both engine and rotor rpm in the narrow, green band. Below it, the manifold pressure indicator shows the throttle-controlled air pressure entering the engine. Around 15 inches of mercury is normal for idle speed. At the bottom are gauges showing oil pressure and temperature, as well as fuel. For what it’s worth, the fuel gauges were often unreliable, and pilots had to rely on visibly checking the tanks, plus time in the air.

With that, it’s time to lift the collective, adjust the throttle accordingly, and take off. At around 20 MP, the Bell 47 springs into a hover, just above the ground.

Hovering is considered the most difficult skill for a new helicopter pilot to acquire. I won’t lie. At first, I wobbled all over the place, but I gradually got better. The key is to anticipate a delayed response from every input. Wait for the helicopter’s response and you will have overadjusted and gone wobbling off in a new direction.

I’m starting to get the hang of it now, so I’m departing the Punchbowl, heading west toward Heartbreak Ridge on a mission to pick up and bring back some wounded. The famous battles of Bloody and Heartbreak ridges took place in summer and fall 1951. After being chased south by the Chinese, who entered the war the previous winter, U.S. troops launched a counterattack to solidify their positions along what would later become the DMZ. They won key ground, at a great cost in lives, but afterward the war bogged down in a stalemate with the 8209th MASH in the Punchbowl never being much farther than 20 miles from the front lines.

The job of the Bell 47 helicopters was to evacuate wounded from the battalion aid stations, where they were stabilized, and transport them to the MASH hospitals, where emergency surgery could be performed. For the first time, helicopters played a vital role in overcoming the difficult terrain that would previously have prevented a soldier from receiving treatment within the critical “golden hour”—the first hour after a wound was sustained. They proved to be a remarkable success. It is estimated that in Korea a seriously wounded soldier who reached a MASH unit alive stood a 97 percent chance of survival once he received treatment. But the ride there must have been a harrowing one, strapped precariously on a stretcher on the side of a helicopter.

According to the manual, the maximum forward airspeed of the Bell 47 is 105 mph. At that point, the retreating rotor blade can’t flap down enough to provide even lift without stalling. I found that the airspeed could creep up on you quickly, and it was better to keep forward momentum around 60 to 70 mph, though 84 mph is recorded as the standard cruise speed. I did have a retreating blade stall at one point but quickly recovered by lowering the collective (to reduce angle of attack) and pulling the nose up to reduce airspeed (the opposite of what you would do in a stalled airplane where you would push the nose down to increase airspeed).

Almost back to the MASH unit. That’s the Punchbowl just past the ridge up ahead.

I was a little overeager to get home at this point, with my airspeed creeping up to 85 mph. It was shortly after crossing the ridge that I had my retreating blade stall. But I managed to arrest it and make my way down into the Punchbowl.

I’m not sure where the 8209th MASH was located, and all signs of it are long gone. But I found some YouTube film footage of it in operation in winter 1952, including the Bell 47 helicopters arriving with wounded. Each MASH unit had 60 beds and was designed to support 10,000 to 20,000 troops in the field. The hospitals were called “mobile” for a reason: They could be set up at a new location in 24 hours. The operating room, recovery rooms, and doctors’ and nurses’ living quarters were all in tents.Many doctors were drafted and didn’t necessarily enjoy the “discipline” of military life. One of them, H. Richard Hornberger, wrote a novel about the experience—under the pen name Richard Hooker—that was later adapted into the movie and TV show M*A*S*H.

And here I am, arriving back at the 8209th MASH’s location—or thereabouts—in the Punchbowl.

Approximately 2,400 of the military versions of the Bell 47 were produced. In addition to evacuating wounded soldiers, they were used to find and rescue downed pilots and recon enemy positions. They continued to be employed until the early stages of the Vietnam War in the 1960s, when they were replaced by Bell Aircraft’s new and improved helicopter, the UH-1 Iroquois, better known as the “Huey.” But the impact of the Bell 47 wasn’t limited to the military, nor did it end with the 1950s. In 1946, the Bell 47 was the first helicopter certified for civilian use by what later became the FAA.

In 1958, Los Angeles TV station KTLA made history by renting a Bell 47. Dubbed the “Telecopter,” it was the first television news copter, scouting out traffic for the city’s auto commuters. Apparently on the first flight, the station wasn’t receiving the signal, so the chief engineer climbed out on the landing skid at 1,500 feet to fix it. That’s dedicated journalism.

The Los Angeles Police Department also acquired a Bell 47 to help it leapfrog traffic and reach crime scenes more quickly. The growing use of helicopters by law enforcement helped inspire the TV series Highway Patrol, which ran from 1955 to 1959 and featured California’s finest chasing down criminals in their Bell 47.

The appeal of the Bell 47 to law enforcement wasn’t just fiction. As late as the 1970s, the Kern County Sheriff’s Office near Bakersfield, California, acquired and flew a Bell 47 until it crashed a few years later. The Pennsylvania State Police, the New York City Police Department, and the Los Angeles Fire Department were among several first responders who looked to the Bell 47 to accelerate their response times. Here I am practicing my stationary hover—and kicking up a lot of dust— in a field outside Bakersfield. I’m getting better.

NASA used the Bell 47 to train its Apollo astronauts, who were mainly fixed-wing pilots, to operate the lunar lander, which had controls like a helicopter.

How high could the Bell 47 climb? Well, in 1949 it set an altitude record of 18,550 feet, and in 1955, French pilot Jean Moine landed on the top of Mont Blanc in the Alps at 15,776 feet after lightening its normal load considerably.

The versatility of the Bell 47 was established in the public imagination by the TV series Whirlybirds, which aired from 1957 to 1960 and featured a helicopter charter company performing all kinds of daring rescues and stunts.

Bell continued manufacturing the Bell 47 until 1974. Approximately 5,600 civilian units—in addition to the 2,400 military versions I mentioned earlier—were produced. This one with floats, flown for Gulf Oil, was one of them.

Gulf Oil operated widely—in the Gulf of Mexico, Venezuela, and Kuwait—so I’m not sure exactly where it flew. But I’m trying it out today at Beaumont, Texas, where the company got its start.

When helicopters operate at airports, they typically taxi (in a low hover) like other aircraft and take off and land using the runway. I’m getting better at controlling my hover, even in a stiff wind. I’m going to fly to the coast of Sabine Lake, near Port Arthur, and see if I can’t try some water landings. I’ve spotted a small oil tanker in the lake that looks like a fitting place to set down.

Most Bell 47s were produced in the U.S., but Bell also licensed production to Agusta in Italy, Kawasaki in Japan, and Westland Aircraft in the U.K. As of 2011, some 1,068 were still registered—and presumably flying—in the United States, as well as 15 in Great Britain. So somewhere out there, the Bell 47 continues to do a day’s work.

Whatever happened to Arthur Young? He quit Bell in 1947, once the Bell 47 was launched, and devoted the rest of his life to philosophy. He founded the Institute for the Study of Consciousness devoted to the “psychopter,” the helicopter as the “winged self,” a metaphor for the human spirit. In 1984, the Bell 47 helicopter was added to the permanent collection of New York’s Museum of Modern Art (MoMA) as “an object whose delicate beauty is inseparable from its efficiency.”

Thanks for joining me to learn the story of the Bell 47, a helicopter that saved countless lives in Korea and established the popular image of the endlessly versatile “whirlybird” in the minds of countless TV viewers.

If you’d like to see a version of this story with many more screenshots and historical images, you can check out my original post here.

https://www.patrickchovanec.com/other/bell-47-1946/This story was told utilizing the FlyInside Bell 47 add-on to MSFS2020, along with liveries produced by fellow users and shared on flghtsim.to for free.