Page 29 - October 2022

was to compare the Model 38P’s performance with the Garrett engine with that of the PT6A-40. Both engines were proven workhorses and different versions already powered the Beechcraft King Air Model B100 and B200, respectively.
Once again, Lou Johansen had the honor of flying the re-engined Lightning on its maiden flight in March 1984. Recognizing that market conditions did not warrant further development of the airplane, company management canceled the program shortly after the initial flight. Yet, the POC continued flying. In an effort to collect as much performance data as possible that could be applied to future certification of the Model 38P, engineering evaluations continued and were conducted in accordance with FAA Part 23 rules. According to Johansen, the PT6A-40-powered airframe made 68 flights and logged more than 55 hours in the air. The PD 336 Lightning flew for the last time in August 1984. The airframe eventually was destroyed.
When it comes to experimental Beechcrafts, perhaps no better illustration of the company’s desire to marry turbine engines to an existing airframe can exceed that of the PD 290. Conceived strictly as a tool to evaluate the feasibility of mating small turbofan engines to a King Air cabin-class airframe, the PD 290 was exceedingly unique. Its most salient feature was two Pratt & Whitney
JT-15D4 turbofan engines housed in specially-designed, over-wing nacelles where PT6A-series turboprop engines normally resided.
The first Model 200 airframe, serial number BB-1, was utilized as the platform to assess the aerodynamic and systems investigations. Veteran company engineering test pilot Bud Francis took the PD 290 into the air on its maiden voyage in March 1975. The airplane flew more than 93 hours during 103 test flights before the program ended in 1977. The PD 290 was the last jet engine-based program until 1986 when the company acquired the Mitsubishi Diamond business jet program and transformed that airplane into the successful Model 400 Beechjet. As for the PD 290, the airframe, sans engines, was placed in outside storage near the factory and scrapped.
Another abortive Beechcraft design that is worthy of mention is the G90 King Air. It was an outgrowth of the Model F90 that was introduced with great success in 1979. From a visual standpoint, the PT6A-135- powered F90 essentially was a Model E90 fitted with a T-tail empennage similar to that of the company’s flagship Model 200 Super King Air. In an effort to offer potential F90 customers a choice of turboprop engines, in 1980 Beech Aircraft developed an engineering testbed unofficially known as the Model G90.
OCTOBER 2022
KING AIR MAGAZINE • 27