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This month we shall take a look at a business jet aircraft that is close to my heart as it is so synonymous with St. Louis. I am referring to the Sabreliner, which is the World's first Twin-Engine Business Jet.
North American Aviation Company (NAAC) broke many records as an aircraft manufacturer, especially during the war effort in the 1940's. NAAC actually built 41,000 aircraft during the Second World War, earning themselves the title of the largest military aircraft producer in the United States, which they held, until they lost their corporate name, when they were merged with Rockwell in 1967. They might be best known for their T-6 Texan; P-51 Mustang; B-25 Mitchell; F-86 Sabre; and later their F-100 Super Sabre. However they also designed and built the L-17 Navion; the BT-9 Yale; the naval O-47; the NA-68; the B-45 Tornado; the XB-70 Valkyrie; the A-5 Vigilante; the X-15; the OV-10 Bronco and the T-2 Buckeye, amongst many other unique and effective designs.
Shortly after parent company, General Motors had taken The North American Aviation Company (NAAC) public on the US Stock Exchange; NAAC conceived the original design of the Sabreliner as a competitor for the UTX program. Lockheed had won that competition with its JetStar design therefore North American was left with an extremely good, twin-engine executive jet design and prototype, but no buyer. This situation did not last for long though, because the US Air Force was quick to select the North American design for a Twin Jet Utility Trainer requirement that they immediately put out for solicitation. This first version was designated the 'T-39', however at the same time it was informally named the Sabreliner, because it's flying surfaces (Wings and Horizontal Stabilizer) were pretty much identical to those from North Americans F-86 Sabre tactical fighter. (This similarly contested by others in the know, that were associated with the North American Navion, because the Navion's wings were also very similar in design to those that are installed on the P-51 Mustang. NAACs thrifty, but efficient wartime policy was obviously still alive and well, long after the Second World War.)
The first T-39 was delivered to the US Air Force in June of 1961. Later in March of the following year, the Federal Aviation Administration issued a US Type Certificate for the T-39 for civilian use. This first version of the Sabreliner Business Aircraft was designated as a model NA-265 and was directly derived from the military T-39A. It flew with two Pratt and Whitney Turbo Wasp JT12A-6A engines that delivered a take-off thrust of 3,000 lbs each. NAAC was quick to obtain FAA approval of its higher gross weight versions of the T-39B and T-39C; commercially designated as the NA-265-20 and NA-265-30. None of these aircraft were ever sold to the public, because NAAC were using the FAA certification of the T-39 series as a stepping-stone towards the final design approval of the commercial version that NAAC wanted to finally bring to market; the 45,000 foot capable, 3,500 lbs thrust, JT12A-8 engined (as an option) NA-265-40, 'Sabre 40A' (the Sabre 40 retained the lower thrust Dash 6A Wasp engines.)
In 1962 the first ever 'green' Sabre 40A, serial number 282-001 left the NAAC factory in El Segundo, California bound for the Remmert-Werner Company at the Lambert St. Louis International Airport. While here, this NAAC sales demonstrator aircraft was completed and out-fitted with a custom executive interior specifically designed to attract the eye and attention of all large American corporations that were potential buyers of this World's First Twin-Engine Business Jet. Remmert-Werner had become well known in the business aviation field as the leading supplier of post-war C-47/DC3 aircraft that were outfitted for corporate use. Their conversions of the DC-3 variants included the installation of a nose radome and the weather radar system below it, an Airstair door, executive seats, interior wood panelling, picture cabin windows, a refreshment galley, propeller spinners, an enclosed lavatory, one-piece heated windshields and landing gear doors. NAAC felt that by selecting Remmert-Werner as their exclusive outfitter, they would quickly realize brisk sales from an already qualified and established client base.
These feelings were not disappointed as Remmert-Werner was quick to line up the launch customer for the Sabre 40A; The St. Louis based evaporated milk producer, The PET Milk Company. According to the modern-day Sabreliner Corporation, serial number 282-002 was sold and delivered to the PET Milk Company back in October 1963, for $989,982 US Dollars.
During 1964, a new Sabre 40A was sold, completed and delivered to its corporate owner, every 18 days from the Remmert-Werner facilities in St. Louis. As new deliveries continued to flow from both St. Louis and Remmert-Werner's rural facilities south of St. Louis in Perryville, Missouri, NAAC was not resting its laurels. Instead they stretched the Sabre 40A by 38 inches, added more of their signature 'triangular' cabin windows, increased the MGTOW to 20,172 lbs and made the JT12A-8 engines as a standard installation, and called this new variant the NA-265-60, 'Sabre 60.'
Almost immediately before the FAA issued the Type Certificate for the Sabre 60 which happened in April of 1967, in March NAAC caved in to public and governmental pressure to merge with Rockwell Standard Corporation after three astronauts were tragically killed by a fire in their NAAC module atop an Apollo rocket on its launch pad at Cape Canaveral in Florida. This tragedy struck a nerve in American society, and the competence of NAACs management was questioned. Now the company that was manufacturing and selling the Sabreliner changed its name to North American Rockwell (NAR) and the business jet division was named the 'Aviation Services Division.'
Rockwell's General Aviation Division had been busy in building and selling their Aero Commander (AC) series of aircraft. With the merger, NAR overnight, became the world's leading business aviation manufacturer, as their product line now included a piston twin-engined executive transport (AC 500 series), a turbine twin-engined executive transport (AC 680 series), and two turbojet twin-engine executive transport aircraft (Sabre 40 and 60.) By 1970, NAR had even managed to add a single engine piston executive transport aircraft, Rockwell Commander 111 and 112 aircraft to their product line. They seemed unstoppable, especially when viewed in conjunction with their FAA approval of, and delivery of the radically enlarged cabin version of the Sabreliner, the NA-265-70. Everything about the Sabre 70 was big. The MGTOW increased by 828 lbs, cabin headroom leapt up by 11 inches, and the fuselage interior volume jumped from 400 cubic feet, up to 460 cubic feet. Unfortunately the Sabre 70 was grossly underpowered since it still retained the same engine that was installed on the Sabre 40 and 60; the JT-12A-8.
The problem of lack of thrust was fixed by the fortuitous introduction by General Electric, of their CF-700, aft-fan series engine. In 1975 NAR quickly took their 70 model and with the help of this new engine, turned the aircraft into the Sabre 75A/80 model (The FAA Type Certificate was issued in April 1975 for the NA-265-80.) The GE CF700-2D-2 engine produced 1,000 lbs more thrust than the older P&W Wasp turbo-jet. This increased power also enabled NAR to increase the MGTOW of the Sabreliner 75A/80 by an additional 2,300 lbs over the Sabre 70, to 23,300 lbs. This radical change in the fuselage design of the Sabreliner placed the Sabre into a new cabin class. Its true airspeed went up by 5 knots, while its range went back to the same numbers that the Sabre 40 and 60 were delivering, which was approximately 1,350 NM.
The period between the certification and delivery of the Sabre 70 and the Sabre 75A/80, another major corporate upheaval came to pass. This time NAR became Rockwell International and spun off its Sabreliner Aviation Services Division into its own entity which was renamed as their 'Sabreliner Division.' Also its El Segundo production facilities were closed, and all production was moved to its Perryville, Missouri facilities (earlier purchased from Remmert-Werner.)
By the middle of the 1970's, the number and types of business aircraft that were competing for corporate dollars had exploded; Gulfstream, Lockheed, Dassault, Cessna, Learjet and others, all had a 'hat in the ring.' It was obvious that if Rockwell's Sabreliner was to maintain its popularity, a radical increase in range was necessary. For this, the company took a Sabre 60 off the production line, and handed it to the famed engineer, Mr. Jim Raisbeck, formerly of Boeing and Robertson Aircraft, who now had his own company: Raisbeck Engineering Company. Raisbeck started redesigning the Sabre 60 which included the installation of a Super Critical Wing that vastly increased the aerodynamic efficiency of this aircraft. This Raisbeck wing latter became an option on the Sabre 80 models, with their designation being changed by the addition of the letters: 'SC.' The Raisbeck Sabre 60 then was mated up with the then Garrett (now Honeywell) TFE-731-3R turbo-fan engines. The FAA approved this new design by issuing its Type Certificate in November of 1979. It was designated as the NA-265-65 and was known as the Sabre 65.
This winning combination of a Super Critical Wing and newer, better fuel efficient engines which produced 400 lbs more thrust, each, over the original P&W Wasp engines, was able to boost the range up to a total of 2,400 NM. The fact that this Sabreliner could make Honolulu from the Coast of California was a major coup. Additionally its cruise speed increased by 11 KTAS over it's predecessors, while it's operating cost dropped by more than 30%.
It is a crying shame that the next generation version of the 80SC, the larger cabin, more efficient and longer range Sabreliner 85 that was under development at the turn of decade, was culled by Rockwell International. At this same time Rockwell International was deeply invested in both their B1 Bomber and Space Shuttle programs and therefore had lost interest in the business jet industry. In 1983 the entire Sabreliner program was sold to a private investment group who called themselves Sabreliner Corporation. With the behemoth parent company gone, this much smaller private company established their headquarters in St. Louis, and then settled in as a service, parts and support company because the very last Sabreliner ever to roll off the line in Perryville had been delivered to it owner, two years before in 1981.
It would be negligent of me not to mention some of the quirky design features that were unique to most, if not all of the Sabreliner marks that were produced between 1961 and 1981. Firstly many who have opened the main entrance door of any Sabreliner, would note that the door is a fully plugging, type design, meaning that an ingenious door throw system had to be designed to enable the door, which had a larger overall dimension that was larger than its fuselage opening, to swing inward and to then exit out, through and down, until it was fully open. Additionally many, who have entered a Sabreliner, have a witness mark on their foreheads, as there was a bridging entrance step above the door and its opening that required you to step over and duck into the cabin entryway. This was necessitated because the original UTX design competition in the 1950's required that the successful winning design should be able to float, after ditching in the sea. NAAC achieved this by designing a hull-lip at its door, i.e. the door opening was above the actual cabin floor level. In a relatively calm sea environment, a Sabreliner could effectively float indefinitely. This design feature has probably added to the longevity of the T-39, which is still in service with the United States Navy and Marine Corps in Pensacola, Florida, to train flight officer students in radar navigation and airborne radar-intercept procedures, in a vast training area over the Gulf of Mexico. All Sabreliner pilots have, after moving into other aircraft, missed the spectacular view afforded by the eyebrow cockpit windows. The Sabre 65 was the only mark of the series that did not have a 'bail-out-door' mounted behind the underneath/behind the belly mounted 'barn-door' airbrake. Lastly it is extremely interesting to note, that other than the heated pitot tubes, engine inlets and windscreens, virtually none of the Sabreliner 40/60/70/75A/80 series aircraft had any Anti-Ice Systems (the Sabre 65 had wing leading edge heat.) Contrary to this fact, the new factory Sabre 75A aircraft ordered separately by both the FAA, and General Motors Corporation (eight aircraft in total), did have inflatable de-icing boots from BF-Goodrich Corporation installed before they were delivered from Perryville. Amazingly, as far as I can tell, there have only been two accidents that are directly attributable to ice. All marks were certified by the FAA for operations in none icing conditions.
In total, 137 Sabre 40/40A; 144 Sabre 60; 8 Sabre 70; 81 Sabre 75A/80; and 77 Sabre 65 aircraft were built (439 aircraft in total.) Currently more than half the fleet (264) Sabreliners aircraft are still in active operation, which is an incredible tribute to everyone ever involved in the design and production of the World's First Twin-Engine Business Jet.
Next month we shall focus on the Learjet 23.
Okay, I will see you next month as we further continue this look-back at the history of the various aircraft that have shaped modern business aviation. If you have a suggestion for me as to a specific business aircraft that one of these future Business Aviation focus articles should be dedicated to, please let me know your thoughts. Also remember that any input that you care to make will be of great interest to all of the readers here at Globalair.com. So don't be bashful. Go ahead and write your comments and suggestions here. Please don't forget that whatever you write here, can be seen publicly by everyone that visits this page, so please be funny, be inspired, but most importantly of all, please be nice.