Rockwell Commander 112
|Role||Four-seat cabin monoplane|
|National origin||United States|
|First flight||4 December 1970|
The Rockwell Commander 112 is an American four-seat single-engined general aviation aircraft designed and built by North American Rockwell (later Rockwell International) starting in 1972. In 1976 they introduced the turbocharged 112TC and a version mounting a larger engine and other minor improvements as the Rockwell Commander 114. A total of approximately 1,000 examples of all models were produced before the production line shut down in 1980.
The rights to the design were sold to Commander Aircraft 1988. They improved the interior and made other minor upgrades to the Commander 114B series, released in 1992. Approximately 200 examples were produced before they shut down in 2002. Another attempt to begin production was made by Commander Premier who planned a Commander 115 series, however, as of 2016[update], financial issues had delayed production indefinitely.
In 1970 Rockwell's Aero Commander division developed a new line of aircraft that would span everything from the fixed-gear four-seat market to a retractable twin-engine six-seat design The first models of this lineup were two versions of a four-seat low-wing monoplane, the fixed tricycle landing gear Commander 111 and the retractable tricycle landing gear Commander 112. The 111 was marketed at $17,950 and 112 at $22,100. Only two prototype Commander 111s were built; the company decided that only the Commander 112 would go into production.
|“||If people bought airplanes based on looks and roominess alone, there would likely be a lot more Rockwell Commanders out in the field. This stout, four-seat single has a stylish look that is noticeably absent among many airplane designs dating to the 1950s and '60s. On the ramp the Commander's rakish nose, towering tail, and upright stance set it apart from its dowdy-looking competitors. Likewise, its interior volume is closer to that of a cabin-class twin than other four-seat singles.||”|
The design had been made to follow the newly released FAR Part 23 standards for light aircraft, which had an emphasis on gust response and fatigue mitigation. The resulting design boasted considerable strength, a fact that Rockwell marketed heavily. Unfortunately, this also had an impact on performance, and in spite of its clean lines the 112 was slightly slower than similar aircraft like the Piper Arrow.
A prototype Commander 112 crashed after the tail failed during testing, which led to a redesign of the tail unit. This delayed the delivery of the first production aircraft until late in 1972. It also led to changes that further increased the weight of the aircraft. This resulted it is being seriously underpowered; the 112 prototype was powered by a 180 hp (134 kW) Lycoming O-360 engine, this was replaced by a 200 hp (149 kW) IO-360 engine in production aircraft. Even with this engine there is widespread agreement that the aircraft was underpowered. Another annoyance was that the fibreglass composite doors did not fit well and tended to leak.
After 123 production aircraft had been built a number of improvements were made to the 112 in 1974, producing the 112A. The doors were fixed by replacing them with new aluminum units, which added still more weight, but had the added benefit of making the cabin quieter. The wing was redesigned internally with increased fuel capacity and a 100 lb increase in maximum takeoff weight (MTOW) to 2,650 lb; After another 30 112s were built, Rockwell offered an option for increased fuel capacity (68 US gallon vs. 48 gallon standard tanks).
The 1976 Commander line introduced two new models, the Commander 112TC with a turbocharged engine of 210 hp and MTOW of 2,850 lb, and the Commander 114 with a six-cylinder Lycoming IO-540 engine of 260 hp. The 112TC had a significantly improved cruise speed of 160 knots (300 km/h; 180 mph) when flying at higher altitudes, as high as 20,000 feet (6,100 m), which was aided by a 32 inches (810 mm) increase in wingspan. However, the low climb performance made this useful only on long trips where the climb time was not a serious issue. In comparison, the 114 was a far better powerplant for the airframe, offering roughly the same cruise speed as the 112TC but at lower altitudes, and the extra power giving it far better climb performance.
In 1977 the wing span stretch of the TC model was applied to the base 112 to produce the 112B. This allowed the 112B's maximum takeoff weight to rise to 2,800 pounds (1,300 kg), giving it a respectable useful load of 1,000 pounds (450 kg). Production of the 112B ended in 1979, while the 112TC was further upgraded with a 50 pounds (23 kg) maximum weight increase and minor detail changes. The major change was a complete makeover of the avionics suite with a three-axis autopilot, producing the 112TCA "Alpine". This offered little more performance than the original 112TC, and was more expensive than similar offerings from other companies. A smaller set of upgrades, notably a three-bladed propeller and a slightly raised maximum takeoff weight of 3,250 pounds (1,470 kg), produced the 114A "Gran Turismo". The 112TCA and 114A remained in production until 1980, when Rockwell shut down the production line with about 1,000 examples of the different models being delivered.
Following the end of production Rockwell sold the design rights to the Aero Commander suite to Gulfstream American in 1981. Gulfstream was only interested in the Turbo Commander, and did not restart production of the 112/114 series. In 1988 Gulfstream sold the rights to Randall Greene, who set up Commander Aircraft to provide support for existing aircraft and build new aircraft.
The design was given a fairly extensive set of upgrades and rectified as the Commander 114B in 1992. Among the changes were a new streamlined cowling, strengthening of the airframe, changes to various air intakes, and a new prop. These improved cruise speed by a significant 8 knots (15 km/h; 9.2 mph), making it more competitive with similar models from other companies. More significant upgrades were carried out in the interior, which received a high-quality leather upholstery upgrade, reading lamps, better soundproofing and an optional powerful air conditioning unit. On reviewer summed it up as "an ultra-spacious interior that looks more like a luxury car than a spam can".
In 1995 they added the 114TC, a version of the 114B with a 260 hp turbocharged engine, primarily to improve high altitude cruise speed to just over 200 knots (370 km/h; 230 mph)s. The company marketed the aircraft primarily to non-traditional markets, namely Wall Street executives via The Wall Street Journal, Forbes, and Fortune, and middle eastern executives, for whom the extremely powerful air conditioning system was added.
The company had plans to reintroduce the 114B and 114TC as the 115 and 115TC. These featured a host of upgrades, mostly to the interior and avionics. However, these plans ended when production ended in 2002 after about 200 114Bs and turbocharged 114TCs had been built, and Commander Aircraft was subsequently liquidated.
Commander Premier Aircraft
In 2005 the Commander Premier Aircraft Corporation (CPAC) was formed by over 50 owners of Commanders, in order to provide spare parts support for their aircraft. Commander Premier purchased the assets of Commander Aircraft from the bankruptcy trustee in mid-2005 and moved all production equipment from Oklahoma City to a new facility in Cape Girardeau, Missouri.
In addition to planning to produce the 115 and 115TC, they also planned on selling a cut-down 115AT ("Advanced Trainer") with a simplified interior, crew training and a complete set of spares, intending to sell it to pilot training schools looking for a high performance trainer.
CPAC was sold to Ronald G. Strauss in 2009, and was to fall under the ownership of Aero-Base, a firm which Strauss owned. While CPAC had failed to establish a stable aircraft manufacturing operation in the city-financed factory at the Cape Girardeau Regional Airport, it did at least manufacture parts and provide aircraft service. In October 2011, CPAC was evicted from its city-owned hangar for unpaid lease obligations. By May 2012, CPAC was back in bankruptcy, the deal by Canadian fiancier Strauss having failed to achieve traction, with an unnamed firm not associated with Strauss showing interest in purchasing the company.
Jim Richards purchased a 1977 Commander 114 and was unimpressed with its performance, and began looking for a solution. This presented itself in the form of the Lycoming IO-580, released in 1997. This is roughly the same size as the IO-540 and only slightly heavier, but offers 320 hp, a significant improvement over the 260 hp of the stock 114. Richards formed Aerodyme Corporation to sell and service conversions consisting of the engine, 78-inch Hartzell three-blade Scimitar prop and a new cowl to fit it. At least one 115 was also converted in this fashion, known as the "Super Commander".
The 112 and 114 are conventional layout monoplanes with the main wing set low and a mid-mounted horizontal stabilizer. This places the stabilizer outside the prop wash, and results in heavier handling at lower speeds.
The cabin is 44 inches (1,100 mm) wide and 49 inches (1,200 mm) high, compared to a contemporary aircraft like the Piper Arrow at 41 inches (1,000 mm) by 38 inches (970 mm). This was the most spacious cabin of any design of the era. There is a full-sized door on both sides of the aircraft, while most aircraft of this class have a full-sized passenger door on one side and a smaller door for the pilot on the other.
The low mounted wing has significant dihedral and features fully faired retractible main landing gear. The gear use the trailing-link design for additional travel and softer "even less-than-perfect" landings. The 112B, 112TC-A and 114A received larger main wheels and disc brakes as part of their upgrades.
Both the wings and fuselage were built using new construction methods that built sections as complete assemblies rather than riveting together many individual parts. The aircraft has far fewer rivets that contemporary designs. As part of the 1976 modifications, various air scoops were moved and redesigned, offering a slight performance increase, while the extended wing tips reduced the stall speed from 62 miles per hour (100 km/h) to 58 miles per hour (93 km/h) in the 112A.
Early models featured front seat three-point harnesses where the shoulder belt was fixed to the seat itself. This was found to offer too little strength and was replaced with one fixed to the fuselage behind the seat as part of a 1987 Airworthiness Directive (AD). In spite of being designed specifically to avoid fatigue issues, the series has been subject to a number of ADs due to fatigue cracking, both in the main wing and the elevator.
- Fixed landing gear variant powered by a 180 hp Lycoming O-360 engine, two prototypes built.
- Production variant with retractable landing gear and powered by a 200 hp Lycoming IO-360, 125 built.
- Marketing name for a strengthened variant of the 112 to meet the FAR23 Amendment 7 requirements with increased maximum takeoff weight, 364 built.
- 112A with an increased maximum takeoff weight, increased wingspan, new propeller and larger wheels, 46 built.
- 112A with turbocharged Lycoming TO-360-C1A6D engine, 108 built.
- 112TC with increased load and higher takeoff weight and other improvements similar to 112B, later named Alpine Commander, 160 built.
- 112 with a 260 hp Lycoming IO-540-T4A5D engine, 460 built.
- 114 updated similar to 112B, later named Gran Turismo, 41 built.
- Variant of 114A built by Commander Aircraft with new propeller, revised engine cowling and a Lycoming IO-540-T45BD engine.
- Variant of 114B with turbocharged Lycoming TIO-540-AGIA engine.
- Super Commander
- Supplemental Type Certificate modification package including the Lycoming IO-580 engine, three bladed prop, and new cowling.
Specifications (114A Gran Turismo)
Data from 
- Crew: one
- Capacity: pilot and three passengers
- Length: 25 ft 0½ in (7.63 m)
- Wingspan: 32 ft 9.1 in (9.98 m)
- Height: 8 ft 5 in (2.57 m)
- Wing area: 152.0 ft2 (14.12 m2)
- Aspect ratio: 7.740
- Empty weight: 2070 lb (939 kg)
- Gross weight: 3260 lb (1479 kg)
- Powerplant: 1 × Lycoming IO-540-T4B5D, 260 hp (194 kW) each
- Maximum speed: 191 mph (307 km/h)
- Cruise speed: 181 mph (291 km/h)
- Range: 813 miles (1308 km)
- Service ceiling: 16,500 ft (5030 m)
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- Niles, Russ. "Commander Aircraft To Be Liquidated" - AVweb Briefs, 19 January 2005. Retrieved: 11 November 2008.
- "About Us". Commander Premier Aircraft Corporation. Archived from the original on 9 May 2008.
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- Taylor, Michael J. H. (1989). Jane's Encyclopedia of Aviation. London: Studio Editions.
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Media related to Rockwell Commander 112 at Wikimedia Commons