Throughout its 84-year history, Beech Aircraft Corporation designed and built a number of experimental airplanes intended to set the pace for competitors to follow. Some designs eventually took wing, but others never made it past the drawing board and faded into obscurity.
In 1940, Walter Beech’s chief engineer, Theodore “Ted” Wells, and his staff were busy creating military versions of the Model 18 Twin Beech for the United States Army and Navy. In addition, he allocated personnel and time to a special project based on the highly successful Model 17 Staggerwing. The idea behind that initiative centered on transforming the negative-stagger wing configuration of the Model 17 into a fast, well-armed fighter and ground attack aircraft.
Since the end of World War I, the Army brass had embraced the concept of a powerful, hard-hitting attack airplane that would blast the way open for ground troops to advance and capture enemy strongholds. During the 1930s, a number of promising designs had been proposed by airframe manufacturers, including (but not limited to) the single-engine Curtiss A-10 Shrike of 1930 and its successor, the twin-engine, all-metal A-18 Shrike of 1937.
Beech Aircraft’s approach, however, would prove to be less than innovative, given that by 1940 biplanes were clearly obsolete and the all-metal monoplane ruled the sky. Preliminary plans for the new aircraft called for installation of a 12-cylinder, liquid-cooled Allison engine rated at 1,000 hp, housed in a highly streamlined nose section. Taking a design page from Bell Aircraft’s P-39 and Germany’s Messerschmitt Bf-109 fighter, Ted Wells’ engineers intended to install a powerful cannon that would fire through the propeller spinner.
The 37-mm weapon would have easily destroyed small vehicles, machine gun nests and buildings, and was supplemented by one 0.30-caliber and one 0.50-caliber machine gun firing through the propeller arc.
The pilot would have had excellent visibility downward, thanks to the upper wing being well aft of the bottom wing. Performance estimates included a maximum speed of 350 mph. As the company continued to prepare for wartime production, work on the cannon-firing Staggerwing ceased and was never revived. Not only was the design woefully obsolete, by 1941 Beech Aircraft engineers were in the initial stages of developing World War II’s ultimate ground attack airplane – the mighty Model 26 Grizzly, also known as the XA-38 Destroyer to the U.S. Army Air Force.
Another development that died on the drawing board was the Beechcraft Model 20M. Based on the general layout of the Staggerwing, the new aircraft would boast two C6S4 “Super Buccaneer” engines built by Al Menasco. The C6S4 was a successful powerplant that featured an inverted, in-line, six-cylinder configuration. It was liquid-cooled using an ethylene glycol mix and was capable of producing 260 hp at 2,300 rpm.
Design work was well underway in mid-1937. Although it seemed a logical next-step for the company to offer a twin-engine Staggerwing, the day of the steel-tube, fabric-covered biplane was fading fast. Despite its obvious obsolescence, the Model 20M would have had a spacious cabin for up to five occupants, including the pilot, and was projected to have a maximum speed of 240 mph. Maximum takeoff weight was projected to be 4,850 pounds and at an economical cruise power setting, range would have been a respectable 600 statute miles. Wingspan was anticipated to be 32 feet and length 26 feet, 9 inches.
Development work was terminated in 1938 when it became obvious that the all-metal Model 18 Twin-Beech was what the marketplace wanted. Entering production in 1937, Ted Wells’ sleek monoplane was becoming increasingly popular with corporations, private pilots and bush operators. To Walter Beech’s sales-driven mindset, there was no room in the company’s product line for the handsome Model 20M and it quickly disappeared.
The postwar years witnessed a sharp increase in sales of Beechcraft airplanes, particularly the new Model D18S and the impressive Model 35 Bonanza that took the private pilot market by storm. Always in search of more sales, company executives and marketing officials were confident that the versatility of the Model D18S could be expanded beyond business aviation and applied to niche markets. One area of opportunity that appealed to those officials was the then infant commuter or “feeder” airline business. In the late 1940s, small airlines, often flying war-surplus aircraft, began popping up across the nation and offered scheduled air travel between rural towns and major airports. These operators were the forerunner of today’s extensive regional airline system.
To compete in that tight market, Beech Aircraft developed the Model D18CT. Unfortunately, this very special Model 18 has been largely overlooked by some historians and Beechcraft enthusiasts. Instead of being overlooked as just another D18S, the D18CT deserves recognition as one of the rarest Beechcrafts ever produced. According to company records, only 16 were built.
Although it was based on the D18S, the commuter version featured a number of major modifications to make it suitable for small airline operations. Foremost among these was a cabin that could accommodate up to nine passengers, installation of two Continental R-9A static, air-cooled radial engines (each developing 525 hp for takeoff) in place of the standard 450-hp Pratt & Whitney R-985 engines of the D18S. The R-9A powerplant was a new development in 1946 and Beech Aircraft received some of the earliest production units for use on its feeder airliner.
In addition to incorporating federally mandated emergency equipment in the cabin, the D18CT’s airframe was built with increased structural integrity and was subjected to extensive and rigorous static, dynamic and flight testing in accordance with Civil Aeronautics Authority Section 04 airworthiness standards. Selling at $64,887, the D18CT had a maximum gross weight of 9,000 pounds with 9,450 pounds offered as an option. At 75% power, the airplane cruised at 224 mph at 8,500 feet and could fly up to 900 statute miles with the optional tanks holding 253 gallons. Approved Type Certificate 770 was issued for the D18CT June 6, 1947.
When Beech Aircraft began production of the Model 35 Bonanza in 1947, its most distinctive feature was the V-type empennage that combined the rudder, elevator and horizontal stabilizer into one compact assembly. The chief advantages of that configuration were lower weight and reduced drag compared with conventional empennage arrangements. In 1944 and 1945, extensive flight tests were conducted by Beech engineers as they probed every aspect of the design’s performance in addition to wind tunnel experiments.
The aircraft selected for those tests was a Beechcraft Model 26 (military name AT-10 Wichita) fitted with the new tail, which was set at an angle of 30 degrees. In 1950, the angle of the V-tail was increased to 33 degrees and chord increased by 20%, beginning with the C35 version.
In 1961, the company built a special Bonanza known as the Model O35. Intended strictly for experimental purposes, the design’s major departure from the production Model N35/P35 was installation of a laminar flow wing that also incorporated integral (wet) cell fuel tanks in the leading edge instead of rubber bladder-type cells installed in the wing structure.
In addition, Beech engineers replaced the standard main landing gear with a trailing-beam design that also required new gear doors. No changes were made to the nose landing gear and the airplane retained the six-cylinder Continental IO-470-N engine of the N35/P35, rated at 260 hp. Despite the aerodynamic superiority of an advanced wing for higher cruise speeds and a trailing-beam landing gear that would help smooth out landings, the experimental O35 project was abandoned and never revived. Key reasons may have included the cost and complexity of building a laminar-flow, wet-cell wing and the higher cost of the trailing-beam landing gear.
In yet another example of modifying a Beechcraft to perform a specific task, in 1965 the U.S. Air Force contracted with Beech Aircraft to modify an S35 Bonanza as a potential light attack aircraft. The S35’s trademark V-tail was exchanged for a conventional empennage and the wings were capable of carrying a variety of ordnance including 250-pound napalm bombs, general purpose bombs and 2.75-inch-diameter unguided rockets and the infamous 7.62 mm “Minigun.”
The Air Force, however, desired a more powerful version and Beechcraft engineers responded by making major modifications to the S35. Designated as the PD 249, the upgraded airplane featured a Continental GIO-520 (geared, fuel-injected and opposed) engine rated at 350 hp driving a three-blade propeller. Wing hardpoints remained unchanged. Flight tests were favorable but the Air Force decided against further development and the program was canceled early in the 1970s.
One of the more ambitious programs tackled by Beech Aircraft during the early 1950s was development of the Model 46 twin-engine, dual-purpose aircraft for the U.S. Air Force. The airplane was designed to meet the service’s specifications for a fast, pressurized transport and pilot trainer to replace the aging Beechcraft C-45s ships that soldiered on years after the end of World War II. In July 1951, the Air Force selected Beech Aircraft to build the T-36A and the company began preparations to build two prototype airplanes.
Powered by two Pratt & Whitney R-2800-52W static, air-cooled radial engines, each developing 2,300 hp, the all-metal Beechcraft had a projected maximum speed of 300 mph, wingspan of 70 feet, a length of 52 feet and a maximum gross weight of 2,500 pounds. It could accommodate three students and an instructor in trainer configuration or 12 passengers and two pilots when used as a transport. Plans called for production of 195 airplanes to begin in 1953, but June 10 of that year the Air Force abruptly canceled the program before the first prototype flew. It was a sudden, unexpected blow to company Chairman and CEO Olive Ann Beech and her executive team, but they accepted the government’s decision and carried on in typical Beechcraft spirit. Both prototype T-36A airframes were eventually scrapped, bringing the program to an inglorious end.
By the early 1980s, Beech Aircraft Corporation embarked on a new era. In February 1980, it merged with The Raytheon Company and became a wholly owned subsidiary of the New England-based organization. Flush with cash and the support of Raytheon executives, Beech Aircraft engineers continued design work on the next-generation Beechcraft – the Starship I. Featuring an airframe built almost exclusively from carbon fiber composite materials instead of aluminum alloy, the Starship I was to be the first of an entire family of all composite Beechcrafts powered by both piston and turboprop engines.
Within that family were two cabin-class, twin-engine airplanes featuring the Starship’s three-lifting-surface configuration of a forward wing (canard), main wing and a T-tail empennage that was swept forward. The general arrangement had become popular in the 1970s for amateur-built, experimental airplanes such the Vari-EZ designed by Burt Rutan and his company, Scaled Composites, Inc., in Mojave, California.
Beech engineers planned to power the new airplanes with either Teledyne Continental Voyager 550 reciprocating engines rated at 340 hp at 2,700 rpm, two turboprop powerplants or dual Williams FJ-44 fanjet engines. The piston-engine version would have had a maximum cruise speed of 305 mph at 25,000 feet, while the turboprop and fanjet-powered versions would have provided much higher performance. Neither of these promising designs were built. The eventual failure of the Starship I in the highly competitive business aircraft marketplace, chiefly due to its high acquisition cost and mediocre performance, sounded the death knell for the anticipated family of all-composite Beechcrafts.