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Business Aviation Industry Focus: Jet Commander

by Jeremy Cox 1. October 2008 00:00
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On November 4th, 1964 parent company North American Rockwell (NAR) , received FAA Type Certificate approval for another twin-engine business jet that was completely unlike their popular Sabreliner design. This new executive jet aircraft design, the model AC-1121, was the work of another of its subsidiaries: The Aero Design and Engineering Company of Oklahoma, which Rockwell had purchased in 1960 and after changing its name to Aero Commander, had categorized this division as its General Aviation Division.

As you may recall in an earlier chapter of this historical Business Aviation Focus, Rockwell's General Aviation Division had been busy in building and selling their Aero Commander (AC) series of aircraft. With the merger/purchases of both North American Aviation (designer and manufacturer of the Sabreliner) and Aero Commander, NAR was fast becoming the world's leading business aviation manufacturer, as their product line now included a piston twin-engined executive transport (AC 500 series), and now two turbojet, twin-engine executive transport aircraft: the Sabre 40 and now the Jet Commander. Later the threat of a suit that was to be filed by U.S. Justice Department against NAR under U.S. Anti-Trust Law would change this situation, but for now, NAR appeared unstoppable.

The true father of the Jet Commander is Ted Smith. He had begun his career with the Douglas Aircraft Company and having contributed greatly to Douglas' war effort by overseeing the design and production of the A-20 Havoc attack-bomber, left them to found the Aero Design and Engineering Company in Norman, Oklahoma where he created the Aero Commander product line. With hundreds of his piston Commander in service and the prototype of his Jet Commander completed and flying, Ted chose to leave the company having sold out to Rockwell three years earlier, before his latest design had received it's Type Certificate. After taking time off from the industry and also after moving to Southern California, he returned by founding the Ted Smith Aircraft Company at the Van Nuys Airport, and went straight to work by designing and building the incredibly fast, twin engine piston-powered Aerostar.

The model AC-1121 Jet Commander which had been redesignated by NAR as the CJ-1121 Commodore Jet was manufactured in a new facility at the Wiley Post Airport, in Bethany, Oklahoma. It utilized a similar cabin cross-section to that of its piston family aircraft; however it was more oval and was much longer with seating accommodations for eight passengers versus the five passengers carried in its much smaller sister. Power was provided by two General Electric CJ610-1 turbojet engines that each produced 2,850 lbs of take-off thrust. It was initially certified to 40,000 feet, but this was later increased after modification, to 41,000 feet with passengers, and 45,000 feet with crew alone. The cruising speed was 527 mph (458 KTAS), which delivered a range of 1,800 miles (1,565 NM.) Although the initial models were pure-turbojets and therefore only stage-1 noise compliant, the cabin was surprisingly quiet. This was made possible by the fact that the passenger cabin was located ahead of the upper-mid fuselage mounted wing, while the engines were mounted much further back on the fuselage behind the wings. The cabin noise was further reduced on later models built in the 1980's, because not only were stage-3 noise compliant AiResearch/Garrett TFE731 engines were installed, there was also an optional long-range fuel tank installed in the fuselage thus separating the boiler room (so to speak) and the passenger cabin.

Approximately 150 AC/CJ model 1121 aircraft were built, but production ceased at serial number 124. This is because right before the Anti-Trust battle against NAR was going to turn bloody in 1967, NAR agreed to sell it off the Jet Commander/Commodore Jet program to Israel Aircraft Industries (IAI) for $25,000,000 1976 U.S.D. Owned by the Israeli government, IAI had first come into being in 1953. Its first jet aircraft was the Fouga-Magister 'V-Tailed' twin-engine jet trainer built under licence from Moraine Saulnier in France. Soon it was designing and building its own aircraft. The opportunity to purchase the Commodore Jet program from NAC was perfect for the Israelis because they could leap-frog from military aircraft into the profitable field of business aviation, by building and selling a well established product. The sale was closed in 1968, and production of the Commodore moved from Oklahoma to Israel and restarted with serial number 125.

By the 1970's IAI was keen to keep its Commodore program as competitive as possible especially against the Dassault Falcon Jet and the Hawker 125; the model 1121 was modified with a longer fuselage (seated ten passengers); increased engine thrust (3,100 lbs per engine versus the original 2,850 lbs); a high-lift wing with double slotted flaps and drooped leading edge; an increased span and travel horizontal stabilizer; increased take-off, landing and zero-fuel weights (an MGTOW of 20,700 lbs versus 17,500 lbs); a slightly increased range thanks to additional fuel capacity through the installation of wing-tip-tanks; and finally the addition of a Saphir III gas turbine auxiliary power unit which provided starting and back-up electrical power, it also provided ground air-conditioning. This new model was designated the model 1123 and the FAA issued its Type Certificate in 1971. Sales of the 1123 were somewhat sluggish for IAI, mainly due to the fuel crisis of the early 1970's. Only thirty four 1123 aircraft were built. At about the same time that other manufacturers were embracing the fuel efficiency of the AiResearch/Garrett TFE-731 engine by replacing their old turbo-jets with them, hoping that it would breathe new life into their lackluster sales; IAI followed suit by designing and building the model 1124 and renaming it the 'Westwind.'

The TFE-731 engine delivered 600 additional pounds of thrust, while specific fuel consumption was almost halved; it dropped from 409 USG per hour for the old CJ610's, down to 248 USG per hour. The range of the Commodore Jet also near doubled, in this latest manifestation, the 1976 Westwind Jet. Later variants (Westwind I and II) came after the model 1124, with little difference between them. The Westwind III, or as designated, the model 1125 was a complete redesign, and was named the Astra.

In all, about 320 Jet Commander type-design aircraft were built in Israel until the program was ended in 1987, one year into production of the then new Astra. This number (320) supplemented by the 125 aircraft built in Bethany, Oklahoma proves that Ted Smith's design was a winner from the start. Approximately 270 various marquees' of this venerable design, remain in service today, albeit rather like orphaned children. This is because IAI sold off the rights to their Jet Commander/Westwind/Astra program, to Gulfstream Aerospace Corporation (GAC) from Savannah, Georgia. The Astra program lives on as the Gulfstream G150, but GAC probably wishes that the existing fleet of the legacy aircraft (Jet Commander/Westwind) passes the point of usefulness and retires to obsolescence, as soon as possible. This has all-but happened for the GE powered versions, but I believe that the fan-powered versions shall be jetting across the skies for many more years-yet.

Okay so next month we shall focus on the Mystere Falcon 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.

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Jeremy Cox


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