Since Beechcraft’s King Air is the most popular corporate turboprop ever built, with over 6,000 units delivered since 1964, it makes perfect sense that third party companies would come up with innovative modifications for most King Air models. Most of the mods enhance the performance, safety, comfort, utility or all of the above. Although all the King Air enhancements are available as aftermarket add-ons by third-party manufacturers, many of these same enhancements have been integrated into the newer models or are now installed by the factory at the time of production.
Summarized below are the many modifications for each series, along with a brief explanation. Most of these modifications have been designed by Raisbeck Engineering, a company that has built a solid reputation since 1982 for enhancing King Air performance and utility.
Description of Modifications
|Dual Aft Body Strakes – Two fins designed by Raisbeck Engineering that replace the single fin on the lower aft section of the tail. The modification improves directional stability and pilot control, improves passenger ride quality, reduces drag and increases yaw-damper inoperative altitudes. In most King Airs, an inoperative yaw damper will reduce the upper altitude limit that you can fly, but not with the dual aft body strakes.|
|High Float Landing Gear Doors – New main landing gear doors designed by Raisbeck Engineering that cover the high flotation landing gear (larger gear for unimproved runways and short fields) which increase aerodynamics and result in restoring original climb and cruise performance lost with the high flotation gear option.|
|Crown Wing Lockers – Streamlined storage space designed by Raisbeck Engineering installed aft of the engines. This adds baggage storage space outside the cabin. Excellent for golf clubs, skis and small surfboards.|
|Ram Air Recovery – The Raisbeck-patented Ram Air Recovery System is a modification of the engine inlet and maximizes the air to the engine inlet so that your engine retains the same power with ice vanes deployed that you get now with the ice vanes stowed. Your aircraft retains speed and power as you climb through clouds or inclement weather. With ice vanes stowed, you experience increased power and speed, and you save fuel—all at lower engine temperatures.|
|Enhanced Performance Leading Edges – Modification designed by Raisbeck Engineering to the inboard leading edge of a King Air 200 series wing that increases climb and cruise performance, reduces stall speeds, reduces wing structural fatigue and provides more efficient air conditioning.|
|Four Blade Props – There are various modifications that change out the original 3-blade props in the older models for the new 4-blade props. Some models reduce vibration, increase performance and increase the time between overhauls.|
|Winglets – Winglets designed by BLR reduce drag, to increase fuel economy, fly faster, improve takeoff and landing performance, improve climb performance, improve slow flight handling and extend range.|
|Speed Stacks – Aerodynamic exhaust pipes for 90 and 100 series King Airs, designed by American Aviation. These increase cruise speed and reduce engine exhaust residue on the airframe.|
|Frakes Stacks – Aftermarket exhaust stacks for all King Airs, designed and manufactured by Frakes Aviation. These stacks significantly reduce soot accumulation on the engine nacelles.|
|Pitot Cowls – Modified cowlings designed by American Aviation for older 90 and 100 series King Airs. They significantly increase cruise speed by 10 to 20 knots. Cowlings are similar to the cowlings on 90 series found in the C90B and newer 90 series models.|
|Garmin 1000 Avionics Upgrade – There are many avionics shops that are now installing complete Garmin 1000 Avionics Systems in King Airs. The installation can include the new GFC 700 autopilot.|
Replacing the standard PT6A-21 engines with the new PT6A-135A increases true airspeed in the 90 series King Airs by 20 to 30 knots, depending on the model. 90 Series with the pitot cowls, C90A’s and C90B’s will cruise at around 270 knots, while older C90’s and E90′s will cruise at around 260 knots. There is also a modification that replaces the PT6A-21 with a PT6A-35, which provides the identical performance of the PT6A-135’s.
Replacing the standard PT6A-42 and -41 engines with new PT6A-52 or -61 engines will increase true airspeed in the 200 series King Airs by 14 to 26 knots, depending on the model. Frequently, modifications to the 200 series are coupled with other Raisbeck modifications such as enhanced leading edges and Ram Air Recovery to obtain even more speed. You can also install the Hartzell/Raisbeck 94″ four-blade propellers prior to King Air B200 serial number BB-1509. After BB-1509, the Hartzell/Raisbeck 93″ propellers were installed as standard by the factory during production.
Raisbeck refers to the installation of the Ram Air Recovery system, enhanced leading edges, dual aft body strakes, new propellers and crown wing lockers as the Raisbeck Epic Platinum package. For newer King Air B200′s, post-serial number BB-1509, the package is referred to as the Raisbeck Epic Gold package and it excludes the propellers because the Raisbeck/Hartzell 93″ propellers became standard as part of the Beechcraft factory’s standard equipment.
Check out the following links for more information and additional modifications:
www.raisbeck.com – manufacturer of modifications for King Airs
www.blackhawk.com – manufacturer of engine modifications for King Airs
www.blraerospace.com – manufacturer of winglets for King Airs
www.blackhawk.aero – owns STC’s for engine conversions for King Airs