The HFS Spitfire Mk.IX Engine Hand Control – An Overview

With the shop open and working it is nice to take a little breather and perhaps share some information from our 74 page Builders Guide which is included in the Plan Set.

Key Features

The HFS Replica is visually and dimensionally accurate per the Spitfire Mk.IX Engine Hand Control. It has been developed from a comprehensive database of original drawings and comparisons with actual installations, including that represented in the DCS World simulator.

Original Mk.IX Engine Hand Control Drawing

The Replica differs from the original in the following respects:

  • The original Airscrew Control was of the Rotol Type, which was a box with threaded control cable arrangement. For ease of use and also to allow users of the Replica in real world (experimental) operation, the box was substituted for a lever while retaining the visual aspects of the original.
Original Airscrew Control Drawing
  • The Mixture Control for the Replica includes two microswitches to sense the position of the lever for purposes of the simulator. This is optional for builders who wish to only use their throttle for display purposes.
  • The machined parts, other than the Throttle Shaft, have been substituted by extremely tough and durable Nylon SLS Printed components.

Environment

The Engine Hand Control has been made available as an intermediate build step towards the full HFS Spitfire Mk.IX Simulator, a full cockpit optimized for VR flight with the DCS World Spitfire Mk.IX simulation software.

It should also be useable for the upcoming IL2 Stalingrad (Battle of Bodenplatte) Mk.IX Spitfire, although typically the systems on this platform are not as accurately modelled as that of DCS World.Inventory.

As a throttle quadrant simulator, the Replica will not operate independently but requires at least a sidewall mounting with the levers connected to sensing potentiometers.

It is intended at this time as a presentation piece. For this purpose plans have been included for an attractive Display Stand which incorporates elements from the HFS Spitfire Mk.IX Cockpit design. The frames and building methods are represented, albeit in abbreviated form.

It may also be used experimentally as a throttle quadrant for aircraft falling in that category (no warranties implied or given!).

System Operations

Going from Left to Right while looking from the rear, the Engine Hand Control has the following functions:

  • Mixture Control/Fuel Shut-Off Lever – This lever operated in a binary On/Off mode on the Mk.IX, with forward being open and back being shut. The microswitches give signals to the simulator as to what the last position was.
  • Throttle Lever – The lever controls the throttle setting and was balanced with the Airscrew Control to set engine revolutions and power (measured as boost with manifold pressure).
    • An Emergency Power (Combat) setting was achieved by pushing the lever to the left then forward past the Gate, a small adjustable plate inserted on the right side of the Quadrant Plate. This could be used for a very limited time before the engine would self- destruct.
    • The handle contains a pushbutton switch which acted as bomb release button on the Mk.IX (it was not fitted to all Marks).
    • There is a toggle switch mounted on the side of the front throttle plate which is activated when the throttle pushes forward and the bracket mounted on the lever’s right side engages the toggle. It only works in the forward direction and its function is to activate the Undercarriage Indicator Lights on the Instrument Panel. It has to be switched off manually by resetting after the aircraft is shut down and its purpose was to automate the switching on process while preserving battery power when the indicator was not in use.
  • Airscrew Control Lever – This lever determines the airscrew pitch setting which affects engine revolutions and power draw. It has an adjustable rear stop plate.
  • Throttle Friction Control – The lever is pulled clockwise to increase the throttle friction. This is useful to prevent creep on the settings while in flight.
General Arrangement and section through the HFS Mk.IX Spitfire Engine Hand Control

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