Page 8 - Volume 16 Number 8

Horsepower increases always enhance climb rate first and speed second. Because the 310-hp engine added 25-hp with an extra three- inches of boost, it’s the climb rate above 16,000 feet that benefited most from the 340A’s introduction. Being able to use more power higher pays off by reaching cruise altitude quicker and raising the 75% power availability to higher flight levels. Even though the early certification basis of the 340A allows the airplane to be legally flown as high as its service ceiling of 30,000 feet, rather than an arbitrary maximum certificated operating altitude, the airplane does its best work in the low 20’s. It is, one has to remember, a light twin, originally weighing less than 6,000 pounds, the certification standard of such designation.The 340 is a favorite target for aftermarket upgrades to solve its stock shortcomings. Boosting takeoff weight by 300 or 400 pounds is available with the installation ofengine upgrades. Vortex generator kits enhance low-speed control and also permit increased takeoff weight (not, however, in addition to increases from any other mod). Electrically-extended speed brakes generate 500-fpm descent rates without risking shock cooling by reducing engine power. Afterbody strakes have just been approved, to enhance yaw stability. Increases in fuel capacity are available by installing nacelle fuel cells from Tom’s Aircraft, adding 20 gallons in each wing locker to replace the seldom-used locker storage space. Cessna originally offered 20-gallon wing locker tanks of its own design, but they were typically only installed on the left side because the air conditioning installation encroached on the tank’s space in the right nacelle.While the 340A’s arrival in 1976 was the major change during the 340’s production run, improvements were made throughout its history.In 1973, the 63-gallon auxiliary fuel system was offered. The storm windows were changed to a frameless style in 1974 and knots replaced mph on the airspeed. In 1975, de-icing boots became available, a single 24-volt battery was used, the ground power plug was moved from under the batteries to the end of the left wing locker, and three-blade props were no longer an extra-cost option. Cessna kept many commonly-ordered items on the options list until introducing “340 II” (1974) and “340A III” (1978) equipment packages, which became de-facto standards.For 1977, flight into known icing certification became available and6 • TWIN & TURBINEAUGUST 2012