As the decade of the 1960s unfolded, business aviation in America was poised to make a major transition from piston-powered to turbine-powered airplanes. Beech Aircraft Corporation would lead that transition by introducing the Model 65-90 – the first King Air.
In 1961 Olive Ann Beech listened intently to her loyal corps of vice presidents and engineers as they advocated a bold, new step for the company. To convince the “boss” that the risk was worth taking would prove no easy task, but Olive Ann was not afraid of a challenge – she had faced them many times before. Although she was not a pilot or an engineer, she was a superb business owner and had an enviable track record to prove it. Few doubted that fact, and by the early 1960s she had established herself as a rising star in the rough-and-tumble, capricious, male-dominated aviation industry.
The shy girl from rural Kansas was no stranger to aviation – she learned the business as “boss” of the office at the Travel Air Company from 1925-1931, where she was known by her co-workers as strictly “Miss Mellor.” In 1930, she changed her last name to Beech and in 1932, amid the depths of the Great Depression, co-founded the infant and struggling Beech Aircraft Company with her husband Walter. She was a key co-executive with Walter during the hectic years of World War II when the company produced more than 7,000 airplanes and built subassemblies for other aircraft.
When Mr. Beech died in November 1950, Olive Ann was more than prepared to step into his shoes as president and chief executive officer and she soon demonstrated that the lessons she had learned during the past 30 years had helped to hone her skills not only as a manager, but also as a “no-nonsense,” uncompromising decisionmaker. The “bold, new step” she heard about that day in the boardroom was nothing short of revolutionary.
It centered on marrying the proven and robust airframe of the Model 80 series Queen Air with the gas turbine power of Pratt & Whitney’s new, innovative PT6A turboprop engine. The PT6 was a major design and technical breakthrough in gas turbine technology that promised to deliver significantly more power than was available using reciprocating engines. Although highly reliable, the large displacement, turbocharged engines built by Continental and Lycoming would remain in demand for years to come; they were approaching the limit of their development in terms of horsepower. The New England-based company’s compact, lightweight and powerful PT6A was among the earliest turboprop engines developed specifically for the general aviation segment (which included business aircraft) and delivered 550 shaft horsepower (shp) for takeoff and 500 shp for continuous operation. In addition, it could deliver more than 1,000 pound-feet of torque to the propeller via a simple, reliable, planetary-type reduction gearbox.
Although development of turbojet engines began in the late 1930s, it accelerated quickly during
World War II and continued into the 1950s, the focus of engine manufacturers was primarily tied to military and commercial airframes, not business aviation. With the advent of the PT6A, however, gas turbine technology that was forged in the “Jet Age” was finally beginning to trickle down to the general aviation market. As far as Beechcraft’s senior engineers were concerned, the Queen Air airframe was a logical match for Pratt & Whitney’s powerplant. All that remained was to convince Olive Ann Beech.
After a thorough investigation of the facts and input from her officials, she gave a green light to what would become known as “Project King Air.” Originally conceived in 1961 as the 300-mph Beechcraft Model 120, the new airplane was officially introduced July 14, 1963, and made its first flight Jan. 24, 1964. The company’s engineering department had grafted the PT6A onto the Queen Air airframe, which had been modified to allow the cabin and cockpit to be pressurized to 3.4 psid (pounds per square inch differential).
Pressurization was not new in aviation, having been developed late in the 1930s and employed successfully on airplanes such as Boeing’s Model 307 Stratoliner airline transport. But in 1963, it was a novel concept for a small business airplane designed to carry four to six passengers and two pilots, yet the engineers and Beechcraft marketing officials believed it would put the company far ahead of the competition – exactly where Olive Ann Beech wanted it to be.
It should be mentioned that the first airplane built with PT6A engines, designated as the Model 87 and carrying serial number LG-1, had been undergoing rigorous flight tests at the Wichita, Kansas, factory since May 1963. Throughout the airplane’s nearly 10 months of intensive testing, company engineers gradually worked out the inevitable “bugs” associated with any new design, especially one that represented a major leap in technology involving not only an entirely new type of engine, but also a highly-modified airframe that came with its own set of unique challenges from the pressurization system.
Designated NU-8F by the Army, the airplane was delivered to Fort Rucker, Alabama, in March 1964 when it began an in-depth evaluation by Army pilots, maintenance officers and mechanics. Prompted in part by the service’s success with the L-23F, of which 71 examples were delivered from 1960-1963, the Army brass wanted an opportunity to take a hard, long look at Beech Aircraft’s latest creation and investigate its potential for military service.
Meanwhile, back in Wichita, preparations were underway to begin production of the Model 90 King Air. With a wingspan of 45 feet, 10.5 inches, a length of 35 feet, 6 inches and a height of 14 feet, 2.5 inches to the top of its swept vertical stabilizer, the Model 90 had a maximum gross weight of 9,300 pounds and a fuel capacity of 122 gallons of jet fuel carried in nacelle mounted tanks with another 262 gallons in wing tanks. Three-blade, constant-speed, full-feathering propellers were standard equipment.
By comparison with current pressurization systems that are fully automatic and often digitally-controlled, “set-and-forget” installations, the Model 90 had to make do with a single, mechanical, Roots-type supercharger mounted in the left nacelle that supplied adequate airflow to inflate the passenger compartment. The primary reason for this necessity centered on the PT6A engine that, in its early configuration, did not have sufficient capability to produce rated power and “spare” enough bleed air from the compressor section to pressurize the cabin – a less than desirable situation that was remedied with more powerful versions of the engine. A pressure relief valve was set to vent cabin air overboard if pressurization exceeded 4.0 psid.
In terms of performance, the Model 90 increased cruise speeds to nearly 300 mph and the Beechcraft marketing department lost no time in espousing the many virtues of the King Air. As aviation pioneer Clyde V. Cessna once said, “Speed is the only reason for flying,” and customers were soon selling or trading in their venerable Model 18s or Queen Airs for the ultramodern, 280-mph King Air. The airplane was enthusiastically embraced by every corporation and company that took delivery of the “jetprop” executive transport. Pilots long accustomed to managing piston engines had to learn how to handle the PT6A-6 powerplant as well as the pressurization system. They were, however, soon singing the praises of the Model 90’s quiet cabin, fuel-efficient engines, ease of handling and its superior climb and cruise performance compared with the Queen Air or competitor’s airplanes.
The company produced 112 Model 90 King Airs from 1964-1966 when production switched to the upgraded Model A90 that first flew Nov. 5, 1965. Equipped with improved PT6A-20 engines developing 550 shp for takeoff, 538 shp for climb and 495 shp for cruise, as well as reversible propellers to reduce landing roll distance, the latest Beechcraft also featured a more capable pressurization system with a maximum differential of 4.6 psid. The upgraded system provided passengers with a sea level cabin up to an altitude of more than 10,000 feet and an 8,000-foot cabin above a cruising altitude of 21,000 feet.
The factory built 206 Model A90s before it was replaced on the assembly lines by the Model B90 that first flew April 13, 1967, and was placed into full production for the 1968 model year. Principal changes from the A90 centered on improved airframe systems but the B90 retained the PT6A-20 engines of its predecessor. Beech manufactured 184 B90s until it was replaced by the Model C90 in 1971.
With the introduction of the King Air, Olive Ann Beech and the Beech Aircraft Corporation had launched business aviation into the “Jet Age” and set yet another standard for the industry to follow. The highly popular King Air series, however, was only beginning to flex its sales muscle and the years ahead would witness development and introduction of an entire “royal family” of turboprop-powered, cabin-class airplanes that served with distinction in both the corporate and military marketplace.