The massive task of numbering of parts and components continues. First a Bill of Materials (BOM) extract was made of the completed model and imported into a spreadsheet. There we could apply part numbers to all the components. This consists of:

• 1182 Components (excluding fasteners) – so all physical bits and bobs that make up the Spitfire without counting nuts and bolts,
• 729 Fasteners (the nuts and bolts)

The process of numbering the model itself is tedious. Each component’s Property Box needs to be opened and the Part Number inserted. Comments such as the material, say “Plywood 21mm” are typed into the description.

All the Components also have an Assembly Number which is hierarchical and shows where the Component fits in the bigger scheme of things. These were added to the model as a first step in order to be able to identify the various Components in the BOM.

In the meantime, we have also completed all the wood designs and drawings. This includes the cutting patterns for all the plywood components which we have sent to our local friendly CNC routing shop for a quote. They consist of the following 2240x1220mm sheets:

• 21mm Plywood: 4 Sheets
• 15mm Plywood: 1 Sheet
• 12mm Plywood: 1 Sheet
• 9mm Plywood: 2 Sheets
• 6mm Plywood: 4 Sheets

There are a further 4 fabrication drawings for the balance of the wooden components.

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Things are tapering down now for the festive season so we probably wont have an idea of prices for the wood routing before next year but let’s see. In the meantime, we number on regardless!

There is a measure of enlightenment bestowed upon pilots. Flying provides a different perspective on the world. It is a something difficult to describe. Fortunately, once in a while, the talents of wonderful writers such as Antoine de Saint-Exupéry, Richard Bach and other gifted individuals provide us with the words we seek.

Squadron Leader Geoffrey Wellum was one such individual. Sadly he passed away in July of this year at the age of 96. He left us a beautiful gift by recording some of his experiences in his marvellous book; First Light.

Here I quote from it. He describes having taken off in his Spitfire for the first time in May 1940, at the ripe old age of 19 years:

“Levelling off, we settle down and things begin to sort themselves out. Possibly I’m just beginning to get the feel of this beast. It’s about time we turned back to the vicinity of the airfield and almost before I realise it my thoughts have been transmitted to my hands and feet and we are turning, a slow and slow and easy turn, the long nose appearing to sweep round the horizon in front of me.

The Spit is beginning to feel like a friendly aeroplane. The cockpit is snug and has a homely feeling. There is a sensation of being part and parcel of the aircraft, as one. This is turning out to be a magnificent machine.

Elation! We sweep effortlessly about the sky, upwards between two towering masses of cumulus cloud and through a hole like the mouth of a cave beyond which lies a valley leading into clear sky. We climb up to the very top of the clouds which stretch away on all sides and I revel in the sheer beauty of the scene around me. Indeed, the very shape of the Spitfire wing is a thing of grace and form. I marvel at its ability to keep the machine in the air. Curved leading and trailing edges, not a straight line anywhere, it’s beautiful.

Looking out of the tiny cockpit as we flow about the cloud dappled sky I experience an exhilaration that I cannot recall ever having felt before.”

Geoffrey Wellum – First Light

Geoffrey Wellum’s book is a must read for anyone with an interest in beautiful prose, the Spitfire and flying.

Not much new eyecandy while we are busy with the rather tedious work of numbering all the components and parts in preparation of the assembly drawings, cutting patterns and so forth. It may therefore be interesting to reflect on some of the great questions we have received.

Your prototype looks beautiful and many congratulations however I have a item for your consideration about VR use in the cockpit.
Haptic gloves or any other type of VR hand recognition will work excellently with all the controls that require manual manipulation and resulting in a tactile feedback.
However movement of the cockpit rudder pedals will require connection to a set of real pedals like the MFG Crosswinds. I am a dedicated VR flight-simmer and operating rudder pedals are a necessity for good flight simmming.
I plan on purchasing you plans and parts but I am concerned about how the rudder pedal problem be addressed?

Many thanks for your interest and your kind words.

I fully agree with your sentiments. In fact, we will not rely on haptic feedback in gloves. The gloves are only to see where your hands are in the virtual space. All controls and switches are fully functional and linked to the simulation program.

This includes fully functional Elevator, Rudder and Aileron control. The last two, being subject to significant force effects due to airspeed over the control surfaces, have been provided with force feedback.

The design therefore incorporates 75 different operating controls, ranging from primary flight controls to sliders, dials and switches. The easiest way to illustrate this is by providing the full control listing: (see attached)

All of this is extremely important for immersion in VR. The project started on the basis that VR provides a fantastically real environment, however what is missing is being able to reach out and touch and feel your surroundings. That is what we have created here.

What screen are you to using – most seem to place the cockpit on the screen

In this application there is no screen. The whole premise of the design is the use of a Virtual Reality Headset for complete immersion. We have created the physical shell to the virtual environment. You are therefore in the virtual environment and by wearing hand tracking gloves, you will be able to reach out to the virtual controls while seeing your hand and operate the physical controls. 
If you have not yet experienced VR flying I would highly recommend finding someone in your area who could demonstrate it to you. It is quite fantastic. However what is missing currently is being able to reach out and actually feel the environment. This is what we are creating. 

Are all the parts to be available as 3D printed parts?

The cockpit is a combination of many different elements:

• There are the plywood frame sections and longerons which will have DXF cutting patterns for the various thicknesses and would be routed out by your selected service provider.
• There are various parts in aluminium plate (and a few in mild steel )of different thicknesses, some of which will need bending, so bending diagrams are included. The plate would be cut by laserjet, again by your local friendly service provider.
• There are standard aluminium extrusions such as round, square and rectangular which will need to be cut to size and often drilled.
• There are a number of turned objects, either mild steel or aluminium, which would need a lathe, so either your own or a fab shop.
• There are bought out items (off the shelf) which would need to be procured. Examples such switches, clevis pins, fasteners etc.
• Finally there are 3D printed parts to recreate unique elements of the cockpit. These are for instance various shaped handles, compass, gunsight etc.

I have just discovered your site. I am VERY impressed. I have a serious collection of original Spitfire parts, I sure would like to display them in one of your cockpit simulators(,not that I would be equipping the project as a simulator) just a very decent display. Are you selling plans with advice OR a completed cockpit?

Many thanks for your email and kind words.

Your project idea sounds great! You could always augment any missing components with our accurate replicas.

When finished, we aim to sell both plans and complete, museum quality cockpits. The plans will provide comprehensive step by step instructions on how to go about the project and how assembly should be effected. Current timing is to have the plans available for sale early in 2019. We are currently re-doing the flight controls before starting with the build documentation and building of the prototype. Quality comes first. Therefore the actual prototype build is important to pick up on any potential glitches and correct them. As such timelines may shift a little.

I am a huge Spitfire fan and have many static and flying models of this beautiful aircraft. I stumbled across your site while researching information for my current radio controlled Spitfire project and I must say your dedication and commitment to detail for your project is outstanding! I have always been into flight simulators and aspired to delve into the custom cockpit builds that many have done over the years and your work has inspired me to to the plunge into my own project for the beloved Spitfire.
So I took the plunge to see what it’s all about and purchased your Throttle Quadrant plans to get a taste for what might lay ahead. I must say the level of detail and comprehensive documentation you have produced is excellent and well worth the price paid. However… I had in my mind that I would be able to complete the project with the resources I had readily available to me that would make undertaking this project financially viable. I have access to a metal engineering workshop through my brother in-law, my own woodworking workshop and a couple of very capable 3D printers. Which leads me to my question. Will you make available the STL files to allow me to print my own 3D printed parts? I had in my mind that they would be included in the package but now understand that they can only be purchased from Shapeways, which for me the cost would be well over $200AUD for items I am fully capable of producing myself at a fraction of the cost with tools I have already invested in.

I regret the STL files are a fundamental part of our business model, with a 30% mark-up on all parts printed by Shapeways. As such they are not made available. It is stated in a couple of places on the site but I will try make it more explicit in the text. 

We have invested the last 18 months full time with researchers, engineers and designers to ensure the accuracy and  functionality of these parts, during which time we have procured the full suite of available Spitfire drawings, over 3400 of them. Where there was no information, as for many of the cockpit related bought-out parts, we got access to and measured up originals from the SAAF museum. There is thus vast IP invested in these models.

Our shopfront states that the full build of the throttle quadrant will cost in the region of US$400. This compares very favourably with commercial replicas being sold at more than twice that price. 

Regarding Shapeways, so far I have not come across another SLS Nylon printing service that provides a lower price. That said, the quality from Shapeways has been superb. I am quite happy to investigate other 3D printing services with shopfronts, I have not found any in Australia though. If you are aware of any, I will investigate that possibility.

Our models in many cases are very intricate and SLS is the only suitable technology to achieve the detail and accuracy required. You are however welcome of course to make your own designs for FDM printing. Some effort will be required but it’s not impossible.

I like your idea of bringing the Spitfire Simulator into next level – to the real world. Do you have any timeline when the simulator parts will be done?Will you supply leather parts, canopy and other parts in the shop?And I would like to know if it will be possible to use simulator also for commercial purposes?

Many thanks for your interest in our venture. In answer to your questions the following:

• Our planning is to complete the designs and prototype build by the end of the year.
• We intend making plans, including construction methods for the more tricky bits available and the 3D printed parts will be available off Shapeways. Leather patterns will be made available, not completed products as these are easily done by local leatherworkers. Our designs are being done to make manufacture and assembly as simple as possible. However, where there are more difficult components to the build, as for instance the Malcolm Hood (bubble canopy) could be, we will consider keeping a number in stock. 
• The purchase of a plans set will licence the builder to build one example of the simulator cockpit. This may be used privately or commercially, for instance by museums or training organisations. The software that forms the basis of the simulator, for instance DCS World’s Spitfire Mk.IX, will be subject to their licence agreements and the builder/operator will need to make their own arrangements in that regard, although we are always available and happy to provide assistance or advice.

I was wondering how wide is the cockpit? 

Attached please find a basic outline dimension drawing. Width at the widest point is 864mm with the skin. 

I was thinking what you said about the number of steps for the throttle control, and I am not certain we will be able to handle it on the first go around. I was wondering if would be possible to purchase all the parts of the cockpit with some parts pre-assembled (like the throttle control). I realize this will increase cost (due to shipping), but I don’t want to get in over are heads and create a bad experience for our students and those involved. Let me know what you think.

I think it’s a fantastic idea to engage your students in the building of the cockpit. I take note of your comment on not having a tech program and would like to share a few thoughts if you would indulge me.

The world is changing rapidly thanks to technology. We are seeing the fourth industrial revolution, aided by the marriage of computing with manufacturing technologies. The great strides being made in additive manufacturing are changing forever the way we view and procure goods and services. The global supply chain, so dependent on mass production, will undergo fundamental change. Why send products across the world and keep huge stores of unused goods when we will be able to print many of our requirements through local agencies. The days of large corporates being the only reasonable means of employment are disappearing. Instead our youth are demonstrating a dynamic entrepreneurship and driving a new village economy with global, online reach. The Maker movement is only one outflow of this, and these are heady, pioneering days.

The Spitfire Mk.IX simulator project is my entrance to this new world. The designs are being prepared in such a manner as to make them accessible to anyone who has ever built a scale model. It relies heavily on making use of local resources and materials. It avoids the use of original parts as I believe these should be preserved for actual aircraft rebuilds and spares.

Putting the simulator together will not require a great deal of technical skill, and such skills that may be required will be easily learnt. The parts are all sent out to local manufacturers, typically maker space type environments, for cutting out and bending to the required shapes. The builder then only needs to assemble by means of bolts and nuts. In the case of the airframe, this is glued together using an epoxy.

And here’s the rub. The build is not only a wonderful team building effort. It takes each participant back in time, providing the opportunity to touch, see and, with VR, relive this watershed period of our history. But more than this. It provides a fantastic vehicle to introduce students to project management skills and the wonderful world of Making.

In essence, skills which will be developed are: 

• Project planning;
• interpreting and understanding designs;
• risk planning and management;
• the procurement process, including vendor identification and selection, negotiation, contracting, expediting, receiving and storage;
• construction planning, execution and management;
• commissioning and close-out, including lessons learnt review.

Benefits to be considered perhaps, before deciding on which route to follow. 

Naturally, I would be able to provide any and all components in a variety of configurations. It is however not something I am actively marketing or particularly interested in. What’s more, these are unlikely to be terribly cost effective when compared with a local procure and self-assembly. I do however intend to offer complete, turnkey simulators to museums and other interested organisations.

In order to allay your fears on the complexity of the build, I have tried to provide as complete a set of guidance notes as possible, amply illustrated. So, voluminous in this case does not represent complexity but (hopefully!), rather the opposite.

And so…. a few answers to some of the questions received. Keep them coming!

This week we have been hard at work with finalising the little details. This included:

• Finalisation of all Intercostals (them little horizontal bits between frames 🙂 )
• Placing screws in all the right places
• Consolidating all the components and making sure they interface properly
• Creating the covering plates and defining their flat patterns

A significant decision has been to do the fuselage covering in 2mm thick 3 ply plywood, followed by a 0.5mm thick aluminium plate to be adhered to the surface thus created. This should give a fantastic and authentic finish. It will almost be a pity to paint this.

Sticklers for detail will be able to add small flat head tacks to represent rivets, but be warned…. there are many!

Now the work starts of ensuring all the components are appropriately grouped, suitable for simplified construction. Then the part numbering commences.

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The Spitfire handling was unusual in the lack of control force harmony. Perhaps it was this very idiosyncrasy which made it such a pleasure in the air.

Now with the Heritage Flight Simulation Spitfire Mk.IX we will be able to put this to the test.

As can be seen from the graph above, the aileron stick force at 110mph was already over 22 lb for full deflection. This increased rapidly to a point where 130mph it required a force of 40 lb to get full deflection and at higher speeds it simply became impossible to move the spade grip left or right to its full extent. At 300mph it took 40 lb to move the stick halfway or 20 degrees. It must be remembered however that as the airflow over the ailerons increased, so did their effectiveness. Therefore it took less movement of the stick at higher speeds to achieve the same roll rate.

Our challenge has been to incorporate this behaviour in our simulator. To achieve that requires some means of force feedback. I have previously written about how we achieved this with the rudders in a novel and much simplified manner from the norm. Similarly we discussed the use of a spring loaded cam system for the elevator as, given the very sensitive and light forces in the elevator, force feedback was not required.

The forces involved in the roll axis are very high however. We therefore needed to find a way of replicating these without placing undue stress on the airframe and preferably using the same actuator used for the rudders. All the while keeping the construction simple and low cost. To arrive at the optimal solution took many days of intense effort; calculating, testing, simplifying and redoing.

The design utilises the wing roots and fuselage underpan to contain the mechanism. We have used four carefully selected expansion springs rigged in series with pulleys to provide a 4 to 1 mechanical advantage. The control lines have been routed back to the 200mm stroke actuator and the forces have been calculated to provide a full spectrum from 0 to 280mph. A fifth expansion limited spring provides low forces typical of the aircraft at standstill, running at 5.6 lb at full deflection. As the airspeed builds, this rapidly ramps up to a full 41 lb at 280mph. (It is unlikely such a force would ever be applied by a pilot in the normal run of things, but it will still be hard to move the stick part of the way.)

We will now be incorporating these changes into the cutting patterns for the plywood and aluminium plate and doing final refinements. Then the task of consolidating all the assemblies will commence and all parts will be properly named and numbered. Final drawing preparation will then be done and cutting, bending and assembly of the prototype can kick off.

The beauty of the Spitfire lies not only in its ellipsoidal wings. As wonderfully illustrated by our featured image, it is amplified by the sinuous curves of the wing fillets. In a touch of brilliance these mould the wings gently into the wing roots and onto the fuselage. Those wide, sweeping fillets  saved huge amounts of interference drag at these critical intersections.

It would be remiss of us not to capture some of this in our design. Simply having a cigar-like structure does not sufficiently evoke the true magic of this aircraft. We are therefore proud to unveil the full shape of our design. If you were wondering how the fuselage was going to be supported, postulate no more. The fuselage sits in a cradle which captures some of the beauty of the wing roots and fillets.

The design accurately follows the original wing roots and fillets, providing a walkway access from the wing into the cockpit, just as if you were climbing into the real aircraft.

Not only does the design provide space for replicating the ailerons with full force feedback installed in the wing roots, it functions as a removable base. This allows the fuselage to be moved through doorways and set down in the cradle before fitment of the fillets.

As pointed out in our previous article, aileron forces in the Spitfire are extremely high, with only half the normal motion available at speeds over 180mph. This, together with the very light elevator forces provided a unique piloting experience which we wish to replicate.

It is intended to leave the rear of the simulator cockpit open so as to allow visitors to gain a unique view into the interior.

The support box will form a solid base for the simulator. It will also serve as the mounting point for a motion simulator should that be employed. Alternatively, placing on a castored pallet will provide mobility where required, for example on museum floors.

A very worthwhile read on how the elegant wing and empennage designs for the Spitfire were developed can be found here. I was previously unaware of the important role played by the Canadian, Beverley Strahan Shenstone, in its formulation and design. Truly, a remarkable man and one of a most talented team to be working with Mitchell on this icon at Supermarine.

With all the excitement of establishing the design collaboration with FlyingIron Simulations (you must check out this link!) mostly over and the necessary information exchanged, we were able able to continue the elevator mechanism redesign. We have abandoned the simple opposing spring mechanism and opted instead for a more precise and smoother cam based system.

Initially the thinking was to also incorporate force feedback, however the stick forces on the elevator in the real Spitfire are very light. We are fortunate in having the results of extensive tests done by NACA (National Advisory Committee for Aeronautics) during 1942. They show that the aircraft has neutral static longitudinal stability, as shown by the fact that no change in elevator deflection was required to trim throughout the unstalled speed range. Typically only 3 degrees up-elevator movement was required to go from level flight to the first signs of the stall. Even when pulling 4g, stick force was only at 13lb. When the aircraft was static, the stick force induced by friction  to pull the stick all the way back already sat at 6lb. All in all then force feedback would be almost imperceptible and not worth implementing.

The elevator cam design turned out to be an interesting exercise. The Spitfire Control Column, when pushed fully forward, is in the upright position. The normal neutral position is 11 degrees back from upright, something very often missed by simulation designers. To move the stick to the fully back position requires another 14 degrees. Any cam design then must take into account this differential.

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The cam and its follower are tensioned with a spring which can be exchanged to fine tune the stick forces.

The support assembly follows the design of the original bellcrank mechanism situated at the bottom of Frame 11.

Next we start on the aileron redesign. This should prove to be a good challenge as the NACA test reports indicate very large influence through speed, to the extent that it was not possible to move the spade grip left or right more than half way (20 degrees) at speeds greater than 180mph. This of course affected roll rate too. But more on that next time!

We are excited to announce that we have entered into a design collaboration with FlyingIron Simulations. Using our detailed interior design, they will be producing the most accurate simulation of the Supermarine Spitfire Mk.IX for X-Plane to date. For those of you who are unfamiliar with their work, head on over to the X-Plane.org store to check out their magnificent P-47N Thunderbolt.

For their debut project this design house has tackled one of the most complex system WWII aircraft. All systems are functional and the artwork is a thing of beauty.

Hence we can think of no better team to tackle this challenge. This will make available to operators of the Heritage Flight Simulation Spitfire another option besides DCS World. It will allow pilots to experience flying the Spitfire in their own environs, no matter where they are based. For museums who would be operating the simulator the cost of a professional licence for X-Plane runs at a once off payment of $750. This in contrast to the DCS World quoted figure of €250 PER MONTH for professional operators!

Now the DCS World Spitfire is a fine simulation, and very reasonable for private users at just a once off payment of $50. But we are extremely pleased that we will soon have more options available to our customers!

Effective rudder control in the Spitfire is a must. In the immortal words of Mary Ellis who flew more than 400 Spitfires and sadly passed away recently at the age of 101, the Spitfire was “a lady in the air, but a bitch on the ground”.

Anyone who has flown the Mk.IX Spitfire in DCS World can attest to this fact. It is only with very accurate rudder action that the beast can be tamed.

Thus we have spent the last two weeks redesigning the rudder pedal action. Originally this was a simple spring based system. We looked at incorporating cams but given the data on rudder forces in the Spit we wanted to do better. At rest the Spitfire rudder pedals move around freely but with some inertia, you are moving a fair bit of weight, cables and pulleys around in the real thing. We thus settled on a pulley system with elastic bungees. Not only did this give the correct feel of inertia, it also opened up new possibilities.

Force feedback is something only the bravest will attempt. All the models I have come across are hugely complex designs with stepper motors and a multitude of pulleys, belts and gears. With the use of a bungee, all that is needed is to stretch it to apply greater force. The stretching is also quite simple with a relatively cheap electric linear actuator. I had previously used one of these in the design of my trim system for my replica Fieseler Storch (70% scale) and they are available with installed potentiometer to provide precise feedback on their position.

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So by incorporating a 200mm stroke 12V linear actuator into the design we have provided a very simple means of accurate force feedback on the rudders. There is fortunately precise data on the stick and rudder forces of the Spitfire from tests conducted during WWII. For the rudder pedals which move some 100mm either way, this amounts to 12lb or 54N at full deflection at full speed. By using a 10mm bungee which provides 46N at 50% stretch and adjusting the moments appropriately, we can achieve the exact force with the actuator at full retraction. Conversely, at full extension the pedal forces are minimal but should give satisfying clunks and inertia when waving them about.

DCS-BIOS will provide the speed reading which will be interpreted by one of the Arduino’s. This will send a signal through a motor controller to handle the 12V and around 3A required for the actuator.

After the fiasco with the Melexis sensors we have now incorporated the Bi-Tech 6127 rotary Hall Effect sensor. This comes in an easy to use potentiometer format and is preprogrammed for various angle ranges. In our case we have selected the 60 degree unit for the rudder. This gives a very nice full range given the rudder pedal’s 57 degree full deflection.

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Next we start looking at what can be done for the elevator.

Just for some weekend fun….

Blueprints were introduced in the early 1840’s to make the replication of drawings somewhat easier. The process used a ferric compound which was impregnated into paper. The process was normally that the original drawing would be made on Cartridge Paper. This was a very heavy paper made especially for rifle cartridges in the days before brass replaced them.

The drawing would then be traced onto a tracing paper with black Indian Ink. This would be placed on top of the treated paper and sandwiched between glass plates. The plates would then be paced in the sun for around 2 minutes (allow 10 minutes for a cloudy day…) and the copier could see the exposed paper turn blue (Prussian blue). When the desired depth of tint had been achieved the copy would be removed and washed. The areas underneath the ink would have remained white, the washing process would remove any remaining ferric compound and preserve the drawing. This would make any changes difficult to conceal and thus the “blueprint” of any plan would form the basis of construction/manufacture and seal whatever contract had been struck.

In order to celebrate the completion of the basic design, we have created a “Blueprint” of the Heritage Flight Simulator in AO size. Printed, this will create a most attractive poster. It’s a fairly large file of 16Mb. Feel welcome to head over to our shop and purchase it…for free!

HFS Simulator Blueprint