Mosquito Blog Post #3: The Engine Control Box
  • Dennis W
  • November 2, 2021
  • 11:55 am
  • 0 comments

There’s more great progress to report on the AuthentiKit controls for the FB.VI Mosquito. We’ve developed the preliminary CAD files for the Engine Control Box (ECB - sometimes referred to as the Throttle Quadrant).

The Mosquito ECB represents the first AuthentiKit control for a multi-engine aircraft. This blog post will go into some level of detail on the ECB functions.

  • Throttles
    • There are two throttle levers on the ECB, for Engine 1 (port) and Engine 2 (starboard) extending out the top of the ECB.
  •  Each throttle lever advances approximately 75% of total travel before hitting a stop.
    • When the stop is reached, there is a spring-loaded catch that when squeezed, will release the throttle to continue to full travel, known as “Climbing Boost”.
    • Merlin 25 engines give 4-12 lb./sq. in. boost at the stops and +18 lb./sq. in. when fully forward
  • Prop Controls
    • The RPM propeller control levers vary the governed pitch of the propellers between 3,000-1,800 RPM.
    • These levers are mounted on the side of the ECB and are topped with (generally) orange grips
  • Supercharger Gear Control Switch
    • The Supercharger Gear Control Switch (SGCS) has two positions, MOD (down) and AUTO (up)
  • When the SGCS is set to MOD, the superchargers will remain in low gear at all altitudes.
  • When this switch is set to AUTO, the electro pneumatic rams are controlled by an aneroid, and will automatically engage high gear when climbing, at approximately the following heights :
    • Merlin 23—8,750 ft.
    • Merlin 25—7.000 ft.
    • Some examples of which position to place the SGCS in are listed, but not limited to these:
      • Climbing
        • Climb in low gear at 2,850 rpm and +9 psi boost. When the maximum obtainable boost has fallen to +7 psi, change to AUTO. Above 18,000 ft. decrease the airspeed by 2 knots per 1,000 ft.
      • Approach and landing:
        • Before landing, check the following:
          • Brake pressure 200psi minimum
          • SGCS: MOD
      • Starting and warming up the engines
        • Place the SGCS in MOD
      • Cruising:
        • Fly with the SGCS in the MOD position, unless the recommended airspeed cannot be obtained without exceeding 2,650 r.p.m., when high gear should be engaged by switching to AUTO.
  • Mixture Control
    • S.U. carburetors are fitted and mixture is automatically controlled by the boost pressure; an economical mixture is obtained when this is less than +7 lb./sq. in.
    • Some models of Mosquito had a lever known as the High Altitude Mixture Control
      • This control is located on the rear of the ECB, and would only be used for maximum economic cruise at high altitude it sets it into auto lean.
      • This control may be included in the AuthentiKit ECB design; currently under review