There is a wonderful little wartime publication called “Bag the Hun!”. Issued in April 1943 by the Air Ministry, it set out improve estimation of opening range and deflection in aerial gunnery.

Shooting down another aircraft from a platform that is moving and weaving across the sky itself is no mean task, as I have found out to my embarrassment on many an occasion with flight simulators such as DCS World. It requires much more than just instinct, and this little booklet was a great help to many pilots, including myself, to achieve greater success. If you do a little search on the internet you are sure to find it.

Which brings me to the main subject of this post. Not only do you need good visual calculating skills, but you also need good sighting equipment to be successful. Enter the Reflector Gun Sight Mark II, as fitted on our Spitfire Mk.IX Simulator.

We have recreated this beautiful optical piece in exacting detail and it offers full functionality within the simulator.

The gunsight has two adjusting rings, one for Range and the other to set the targets known wingspan in feet. In our case the rings do not adjust the optics but turn two independent potentiometers to provide a signal to the simulator. This required fairly intricate internals as can be seen from the exploded view below:

The gunsight also incorporates a dimming screen to better show the aiming reticule in bright light, this can be slid up or down as required. Microswitches indicate to the simulator what the position of the screen is.

The assembly fits into the simulator fuselage beautifully and complements the already impressive panel.

A few more pics for your viewing pleasure:

 

Just a reminder that there is still one day left to pick up the Spitfire Mk.IX Engine Hand Control plan set at the introductory price of $55. From tomorrow the price will revert to its normal $70.

Spitfire Mk.IX Presentation Engine Hand Control Plan Set

 

The Instrument Panel is complete and the Six Pack is a thing of pride!

The panel consists of two main components; the main panel and the Blind Flying Panel, also known as the “Six Pack” as it contains the six elements most important for flying in cloud and dark.

In the top left of this panel you will find the Airspeed Indicator. Variations in this, up or down, will likely be the result of the nose being pushed under the horizon or pulled back, in that order. So if your airspeed is increasing and you haven’t touched the throttle, you are most likely heading for the ground!

Next up, working clockwise, is the Artificial Horizon. This is the prime indicator of where your nose is pointing and works on a gyroscope.

Then comes the Vertical Speed Indicator or VSI. Another indicator of whether you are going up or down but considerably more sensitive than the Altimeter which comes last.

The Turn and Slip Indicator is particularly important in gauging the steepness of your turn and making sure you balance elevator, ailerons and rudders in the turn. This to prevent slipping into the the turn or out of it, all of it important to gauge and maintain accuracy of a turn and keep navigation precise.

We then get the Gyro Compass Repeater. In itself it does not provide direction. You have to set it using your bet guess of what the magnetic compass is showing. You then turn the knob to show the same heading and for the next ten minutes or so it will provide a much more stable readout than you could get from the wildly swinging compass. You better check it again though in another ten minutes or so as it gradually creeps out of true.

Finally we have the altimeter. Important to gauge against the known (or suspected!) height of the ground. You set it by turning the knob when you’re on the ground to match the indicated altitude with the known ground altitude. It works of barometric pressure so will vary according to weather conditions and temperature.

Our panel accommodates nine switches, four rotary encoders and four potentiometers, accurately reflecting all the functionality of the Spitfire Mk.IX Instrument Panel.

Remember the gauges themselves are relatively cheap 3D Prints, each with a decal and acrylic glass cover. The working gauges will be found in your Virtual Reality headset 🙂

Speak to Spitfire builders and restorers about a particular Frame and they immediately can visualise what it is and where on the aircraft it is situated. So it is now with us here at Heritage Flight Simulation 🙂

So when I tell you about Frame 11  many of you will know that it is the substantial frame right behind the seat. It holds such items as the headrest and armour plating on the front and it has aluminium cross members that form the support for the cantilevered seat. It is a substantial member of the fuselage and the one with the greatest cross-section.

It was therefore fitting and exciting to use it as a sample for the waterjet cutting procedure discussed in the previous post. We had the ten pieces cut a week ago.

First we needed to spend some time to repair the water damage but were able to lay the pieces up for gluing yesterday. We used a local epoxy known as Epidermix 372 but there are many suitable epoxies for wooden aircraft and boat building.

We sandwiched the layers between two MDF boards with weights stacked on top to apply some pressure. This morning we took off the weights and the results are exciting. The frame weighs in at 3.42kg vs the predicted 4.6kg. It is a very substantial and sturdy construction and gives one a sense of the overall size of the simulator.

The cutting came out extremely accurately, but as mentioned in the previous post, we will be doing the cutting with a CNC router in future to avoid the waterdamage.

This little milestone is just one step closer to what is turning out to be a very exciting project.

 

Waterjetting of plywood

One of the basic assumptions I have been using is being able to waterjet cut plywood. To test this I cut up various thicknesses (6, 15 and 22mm) to produce the bases for the Presentation Engine Hand Control stand and a sample of Frame 11 of the cockpit (6mm outer, 22mm filler).

It was evident that while the cuts are extremely accurate, the very high pressure penetrates between the ply layers at times and cause damage. The wood also gets pretty wet and the moisture penetration causes warping.

Good news is…CNC Routing!

It was therefore a relief to find out that I can have the same patterns CNC routed at a significantly reduced cost. Using a 6mm router bit results in the sharp inner corners having a radius of 3mm, but this is easily removed with a file.

 

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.

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.

• 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.

We are pleased to announce that the Heritage Flight Simulation shop is now open for business.

As an introductory, once off special celebrating this event we are offering the complete plan set for the Spitfire Mk.IX Presentation Engine Hand Control at a sale price of USD55.00

This is $15.00 below the regular price of $70.00 which will come into effect on 14 May 2018.

The plan set comprises a 31MB download of the Build Guide and all relevant drawings and cutting patterns. Please note Conditions of Purchase.

This display model covers the full ambit of information to be provided for the complete build, amongst others:

• Cutting patterns for plywood and aluminium (Waterjet or Lasercut) (7 off GA’s and 8 .DXF files)
• Assembly drawings (2 Off)
• Bend Diagrams (14 Off)
• Engraving Templates (3 Off)
• Machine drawings (1 Off)
• General Arrangement Drawings (5 Off)
• Powder coating guideline (1 Off)
• Parts list with various summaries
• Step by step instructions including explanatory assembly graphics in a 74 page Builders Guide.

All of these are included in your purchase pack.

All the necessary 3D printed components can also be ordered using the shop links to our Shapeways site.

Great progress is being made and we have assembled the prototype parts for fit. I am really impressed with the overall outcome. We have made some mods since to further refine the design and make manufacture and assembly faster and easier.

The plans and 3D printed components will be available from the end of the month. In addition we will be preparing 40 presentation throttles to sell as complete units. These will be powder coated and engraved.

In keeping with our mantra of “Making Historic Flight Accessable”, we look forward to offering an extremely high quality replica to enthusiasts at reasonable cost.

Some of you might have noticed the glitch in the matrix when our site went offline yesterday. Nothing to be concerned about! We have successfully migrated to a new hosting site in order to establish our shopping capability.

As promised, we will be making available the Presentation Throttle Quadrant at the end of this month, and this essential step was just one part of the process. Roll on end April!

We have started on the Instrument Panel and things are coming along nicely 🙂

The panel consists of a main panel and the “Blind Flying Panel” or six-pack. We have placed the magneto switches and had a very interesting time researching the clocks that were installed in the Spitfire.

The earlier marks of Spitfire did not generally have a cutout for a clock and it is apparent that many different types of clocks were employed from various manufacturers. It would seem most of the clocks utilised called for an 8 Day life after a full wind.

The DCS World Spitfire Mk.IX’s manual notes that the clock employed in their model is a Mk.IV (106A/322) Aviation Watch. “The watch is designed to display the current time in hours, minutes and seconds. It has a crown at the bottom of the device. The pendulum is used as the operating principle. The construction is of a common spring pendulum clock with a round-balancer. Power reserve is good for 8 days.”

We have thus based our clock on this design, using the internal face of a Longines WITTNAUER US TYPE A-11. This model is the 7 jeweled A-11 with 2 barrels for 8 days reserve power.

Remembering that this is to be used in VR, there is no need to model the actual internals and a decal has been placed on the faceplate. That is covered by a disc of 1mm clear acrylic.

The knurled crown can be rotated to either side to send a signal to the simulator to increase or decrease the time setting. This is achieved by means of a lever at the rear depressing one of two micro pushbuttons.

We have also taken the opportunity to refine the design of the starter and booster coil button covers. A clip has been incorporated to ensure the cover remains in place when closed. The intricate detail that can be incorporated in 3D Printed designs at no extra cost never ceases to amaze.