Of all the models of propeller planes flying in Brazil, the company Clear Prop Aircraft concludes that the King Air and all its series and versions occupies the third position in of the total number of aircraft flying regularly, according to ANAC, through the RAB. The plane becomes even more important for the aeronautical industry when we that it is the only twin-engine turboprop model in longer production in its category. However, we believe in the reader's interest in knowing more about its history, evolutions, milestones, and we publish the article here, on Aeroflap.
Anyway, the famous King Air had production started in 1964 and finished in 2021. On the surface it even looks like the same plane, but throughout this article you will see that there have been so many changes, that the plane has become one of the most modern in its category in the world .
First King Air produced in front of the Beechcraft building, in 1964.
The King Air is manufactured by Beechcraft, which started the journey by creating the first aircraft with a turboprop engine for business aviation, in 1961, in order to fill a gap between piston aircraft and “pure jets”. The first project was titled “model 120”.
"Model” 120 (prototype) and other planes produced at the time
Note that the entire structure and wings were completely different from what already existed in current Beechcraft products.
"Model” 120 (prototype)
According to the book “BEECHCRAFT: 50 YEARS OF EXCELLENCE”, the company decided not to go ahead, as they concluded that the time and investment needed were unfeasible.
Until, in 1963, in order to meet a request from the US armed forces, Beechcraft made some changes to the already consolidated Queen Air 80, replacing its current Lycoming piston engines of 380 hp each, by two turboprop engines newly created by Pratt & Whitney, PT6A-6 with 500 shp. This version was called the Queen Air 87, but later renamed the NU-8F (10) due to the military designation. This plane had square windows because it was not pressurized.
NU-8F (Queen Air 87)
The engines fit together so well that the factory invested in the same changes, but in the pressurized model of the Queen Air, the 88, which already had the famous round windows, thus transforming it into the most successful project in world business aviation.
Queen Air 88 (piston engines)
The announcement of the development was made in July 1963, the same year of the first flight of the predecessor Queen Air 87 and was designated as King Air 65-90. Surprisingly, a few months later, King Air successfully performed its first takeoff, more specifically in January 1964. In October of the same year, the first deliveries began.
Interesting to say that in the same month 152 reservations were made!
King Air 65-90
This plane was equipped with the same 500 shp engines, capable of making the plane fly at a speed close to 210 knots, level. The pressurization system only provided 3.1 psid of differential. To get an idea of what this means, it's as if the plane flew at 16.500 ft and the cabin remained at 8.000ft, which is terrible nowadays. Pressurization was provided by a hydraulically powered compressor located in the left engine nacelle. The cabin's internal temperature was controlled by the pilot who adjusted the external air flow over this compressor – which cooled the hot air generated – and the internal heating was also complemented by a combustion heater.
In 1966, a new version was created, the A90 that brought new engines, the PT6A-20 with 50 shp more power, but limited to the 500 shp before; in this model the propellers had the reverse pitch. The cockpit was redesigned, providing better ergonomics and adding a pedestal for the levers that is still standard in the King Air family today. As for pressurization, that complex compressor was changed to one mechanically driven by the engine, which made the pressurization differential increase to 4.6 psid. For comparison, it means that the cabin remains at 10.000 feet while the plane is flying at 25.000 feet. Interestingly, this version already had an extra side window on the right side of the plane.
Cockpit of the first King Air, the 65-90
King Air A90 cockpit. Note the pedestal of the levers equal to the current ones
The A90 was in production for two years, when in 1968 it was replaced by the B90.
The systems and engines remained the same, although it was the first time that the use of 550 shp of power was allowed. In this version, there was an increase in the wingspan, the ailerons and elevators were remodeled and gave greater controllability to the plane. The automatic feathering system for the propellers was now supplied as an option. A few years later, still during production, there was the introduction of an additional pressurization system by direct bleeding only in the right engine. When used, the cabin became hotter and noisier. This supplemental system was used when the booster compressor failed.
In the year 1971, the King air underwent further changes, with the next model appearing, the C90. As verified by the team at Clear Prop Aeronaves, this version had the same performance, size, weights and flight controls as its predecessor, but the changes began in the pressurization system and internal temperature control of the cabin. That old compressor was discarded and a bleeding control system for the two engines, the “Flow Packs”, was installed, which brought comfort and a quieter cabin, in addition to greater safety and efficiency, because the pressurization worked regardless of the regime applied. or when an engine failed.
In 1972, Beechcraft introduced the King Air E90, after giving up producing the D90, which was a lighter aircraft, but also a shorter range. The marketing of the E90 followed in parallel with the C90.
The then new plane has the same fuselage, but with more powerful engines, the PT6A-28 of 680 shp, but limited to 550 shp. The wings and some systems were also changed. In fact, they were used from another King Air produced, the 100, which is basically a 90 with a longer cabin, a larger wing and the same engine, but without power limitation. Finally, the greater engine power available, despite the power limitation, allowed flights with higher speeds and takeoffs with greater weight. Also, the E90's larger wings carried larger fuel tanks, allowing it to fly further.
Going back to the timeline, a few years later, the engine supplier Pratt & Whitney studied a new engine for the C90, which performed better and made the pressurization system more efficient, without that air bleeding stealing so much performance. It was then, in 1975, that the PT6A-21 was installed on the C90 and used until 2006. The compressors were more powerful, because they came from the -28 engines that equip the Kings 99, 100 and E90, but in the -20 engine reduction box , the old one. That way, it allowed for better performance, especially on climbs. However, this “extra” performance put pressure on the attitude angle, which made engineering add a 12-pound counterweight behind the instrument on the elevator controls. Consequently, pulling the stick during the landing flare required more stick force than in previous versions. Finally, even with another engine, the speeds are the same, since the engine operating limits had only a slight change.
Four years later, in 1979, another King Air model was introduced to the market, the F90 which was marketed alongside the C90 and E90.
King Air F90, produced with the C90 and E90
The F90 has the same fuselage as the “90”, but with the “T” tail and door coming from another King Air series, the 200; the wings on the F90 are from the E90. This was also the first aircraft in the series with the four-bladed King 100 propellers. The engines are the then new PT6A-135 with much more power, 750 shp. With a powerful engine, the plane delivered speed greater than all of the series, and a quieter cabin because it allowed less rotation of the propellers in flight.
From 1982 onwards, with further changes, the C90 was renamed the C90-1. In this model, a more reinforced door was installed, increasing the pressurization differential from the old 4.6 to 5.0 psid. Even in this version, the factory guaranteed 15 kt more speed… No other changes were made! That's right, what you read, the plane is the same, same fuselage and wings, unchanged engine, but with 15kt more speed. It sounds disturbing, but the answer is simpler than you might think: on the C90-1, the factory allowed extended engine operating limits, and they didn't do that before, because it would simply make production of the E90 unfeasible, simple as that! As the E90 was taken out of production in 1981, it was “okay” for the C90 to bring higher performance.
The following year, in 1983, the F90-1 replaced the predecessor F90. In this version, the engine fairings were redesigned, which brought benefits to the operation, such as lower temperatures in the turbines. The F90-1 also had the engines modernized for the PT6A-135A.
Returning to the evolution of the C90, the -1 version was refurbished and again in 1984 another replacement model appeared, the C90A. The biggest change was in the landing gear system, where the old system was replaced by a hydraulic one. The engine fairings were taken from the F90-1, which made the engine operating limits slightly rise, giving greater speed and weight capacity, which was even extended once again in 1987, giving the same weight value as the old E90 . The cockpit was also changed, where the landing gear lever moved from the copilot's side to the commander's side.
Following the timeline, in 1985, the F90 ended its production with 11 units delivered in the same year and with the hydraulic landing gear system as in the C90A.
In 1992, after an agreement between Beechcraft and McCauley, all Kings Air in production began to receive propellers with four blades as standard, which made the C90A to be denominated C90B. In addition to this change, Beechcraft focused on reducing internal cabin noise, with changes in sound insulation engineering. In this model, a new set of avionics was added that was more modern and electronic.
Naturally, the innovations made the C90B more expensive than the old ones. However, catering to more price-sensitive customers, Beechcraft introduced the new C90SE, which were sold in parallel with the B, from 1994 onwards. have those old "watches". The partitions between the cockpit and enger cabin, which are normally equipped with drawers, were also replaced by simple curtains on the C90SE.
Cockpit of the King Air C90SE, marketed from 1994
This new version ended production in 2001.
With the emergence and growing sales of single-engine turboprops, such as the Pilatus PC12 – which performed much better than the smaller King Air – the author of this article, Rafael Payão, manager of Clear Prop Aeronaves, understands that “Beech” was forced to to bring more powerful engines to the C90, announcing with that, the C90GT, which took the place of the B, from 2006. In it, the installed engines were the PT6A-135A with 750 shp, but still limited to 550 shp. With more thermodynamic power left over, the plane was able to fly at higher cruising speeds and also faster climbs.
Two years later, the C90GTi was introduced. In it, there were not so many changes, except the “glass cockpit”, with the Proline 21 as standard.
In 2010 the series underwent its last airframe modernization with the C90GTx. In it, winglets were added and, in 2016, the Proline 21 was replaced by the Proline Fusion with larger screens and touch screen capability.
King Air C90GTx cockpit with Proline Fusion dashboard
Talking a little about numbers, after all one of the goals of Clear Prop Aircraft is to bring complete, accurate and intelligent information, in Brazil the Kings Air series 90 are the darlings of turboprops, with 284 planes flying regularly until July 2021, according to ANAC, and, occupying the seventh position in of number of planes to be propeller – independent of the engine – flying in the country.
Also, a curiosity is that if we added all the King Air models with Brazilian registration, the number would occupy the third position in of total flying in Brazil with a propeller, with the subtle difference of only four planes less than the number in the second position, occupied by all versions of Baron flying. The leader in this list is Seneca and its versions.
Unfortunately, the Textron Aviation group, which recently owned the brand, has defined the closure of production of this memorable machine. There are those who say that the decision was guided by the fierce competition of more economical and efficient projects, or that the C90 would become a thorn in the side of the new Denali, which will be launched soon and which belongs to the same factory. The fact is that deliveries in recent years have not come close to other models in the King Air family, remaining only at 328 aircraft produced since 2008, against 714 of the larger brother 350i. And, the trend is visibly downward in the number of annual sales, despite the 2.245 aircraft of the 90 series already delivered in the world, which are slightly below the sales champion, the 200 series.
Well, the big question is that today there is no other twin-engine turboprop aircraft currently being manufactured, with the size and value equal to the C90. In the past, there were even some competitors, but they weren't good enough to take the King Air off its throne. Among them, highlight the Mitsubishi MU-2 that even had its project started years before, but deliveries started later and there were still accidents related to the operation that affected its image and harmed sales. Another plane was the Twin Commander 680T announced in 1964. This plane had so many problems that its certificate was canceled during the first deliveries, making the factory have to significantly change the plane to be accepted, only becoming relevant in the market from 1971 with the first 690.
Anyway, there's more information and stories about the King Air, but the article would go on even further.
If your goal is to purchase the ideal aircraft for your goals or dreams (even the King Air), Clear Prop Aeronaves. Our customers are not surprised by unforeseen events that were not planned beforehand, because we have experience and, above all, knowledge. Follow @clearpropaeronaves on Instagram and follow content about executive aircraft management and other curiosities.
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