FlyingIron Simulations Spitfire L.F.Mk.IXc Released!

In what has been an amazing whirlwind of activity over the last just under 4 months, FlyingIron Simulations have released their L.F.Mk.IXc Spitfire for X-Plane 11. You can find it here on their site (AUD$) or here on the site (USD$)

The Heritage Flight Simulation Spitfire cockpit internals which were meticulously drafted over the last year and a half formed the basis of this masterpiece and probably cut down the development time by a few months. That said, Alex and Dan Kassabian, the two Sydney Australia based brothers who formed FlyingIron Simulations, have an astonishing track record in creating exceptional aircraft in an amazingly short span of time. Their fantastic P47N was created in something like 3 months. These guys just never sleep!

Alex is the master artist who took the cockpit internals and deftly reduced their polygon counts in order to create an aircraft that has very little impact on framerates. While we had a good commercial copy of a Mk.V model available to us, Alex decided to design the Mk.IX externals from scratch. The result has been nothing short of amazing. The textures applied to the aircraft exterior and interior have resulted in a thing of real beauty.

Spitfire Mk.IX in post 1947 SAAF livery

Dan is the coding and sound expert and built the flight model and all the custom aircraft systems. This has resulted in an aircraft which has an extreme level of realism. The aircraft has been exhaustively tested in the last month and is running to the manufacturers numbers. The roar of the Merlin (you can chose between a 66 and 70) is something to experience!

The aircraft was designed from the outset to be VR optimised and utilise all the latest effects in X-Plane 11.3 All the controls in the aircraft can be manipulated and have an effect on the operation of the airplane. I suggest you have a look at their link above to get the full gist of what they have achieved. Better yet, go purchase a copy. If you are in any way a Spitfire enthusiast, and I am assuming you are if you got this far in the article 😃, you owe it to yourself!

Why my interest in having an alternative to the great Spitfire Mk.IX simulation in DCS World, which, through VR, also puts you in the cockpit as if you were really there? The reason is twofold:

  • X-Plane allows you fly the aircraft anywhere in the world. You can explore the British Isles, practise your skills in Toronto or land in Darwin Australia. The Ortho scenery such as the TrueEarth Great Britain from ORBX is remarkable.
  • For museums wishing to run the HFS Spitfire Simulator on a commercial basis X-Plane is a lot less onerous than DCS World. It requires a once off professional licence for $750USD. In contrast, DCS World have quoted some EU250 per month for the same privilege.

Heritage Flight Simulation approached various X-Plane developers with a request to collaborate on creating an exceptionally realistic Spitfire Mk.IX simulation. Mostly the response was that their interest (and income) lay in General Aviation aircraft. It is a pity therefore that we have many incarnations of the Spitfire in X-Plane which have low levels of authenticity, most having been developed many years ago. Graphically and systems wise the X-Plane platform has advanced tremendously, more’s the pity that this has not been capitalised on by historical aircraft developers.

Fortunately though, when I approached Dan and Alex on the basis of their stunning P47N which had just been released at the time (get it here), they responded with enthusiasm. It has been a real pleasure working with these two exceptional young men. They have a real love for keeping aviation history alive and I am waiting with great anticipation on what they may have planned for their next effort!

Prototype Build – Volume 1 Part 2: Plywood Routing

After going out on enquiry with a sample cutting file to five different vendors we have selected CNC Lab in Randburg, South Africa to do our wood routing. We ordered the thirteen sheets of plywood and had it delivered directly to the CNC shop.

Plywood quality

A word on the quality of the plywood. There is a confusing array of grade classifications, including Brazilian, Malaysian/Chinese, Chilean, Finnish, Russian and Swedish amongst others. Here in South Africa we seem to use the Brazilian grade nomenclature. They have an excellent spec sheet which can be downloaded here:

This is an extract from their grading criteria page:

In brief, we use a combination of the letters to indicate quality front and back:

  • C+/C Face knots filled and repaired/reverse open knots
  • B/C No knots in face/open knots in reverse
  • B/B No knots face or back

We have stuck to using B/B grade Pine plywood. This gives a balance between quality and cost. According to the CNC shop we are using Birch ply gives a much better result with less ripping, but that comes at twice the price. Hence it will be fine for us to fill in the areas where some ripping has occurred – it all gets painted in the end anyway.


The routing started today and a number of the 6mm panels have been completed. This work will continue over the next few days and should be completed this week. Initial results are looking great.

Setting up of the CNC Router


Together with the CNC shop we have decided that the easiest and cheapest way of numbering the parts will simply be to scribe the code on the part with a marker pen. We did consider laser engraving but for this it simply is not cost effective. (It is something we are considering on the metal parts that will be plasma cut, but that is simply because we have less control in that process).

The numbering is kept simple, giving the thickness of the ply, the drawing sheet number and the item number on the sheet. That’s easier than having to put in the actual Part Number

6mm parts with the numbering visible
Example of the sheets showing their item numbers unique to that specific sheet

With any luck we will be able to start gluing up over the weekend! 🙂

Prototype Build – Volume 1 Part 1: Wood Preparation

The Prototype build has officially begun! All the wooden cutting patterns have been completed and guidance drawings prepared. The cutting patterns are ready for any CNC Routing shop which can handle standard 2440mmx1220mm pine plywood sheets. The sheet thicknesses are as follows:

  • 1 off 3mm
  • 4 off 6mm
  • 2 off 9mm
  • 1 off 12mm
  • 1 off 15mm
  • 4 off 21mm

The cost for these sheets locally total around US$430. We have appointed a routing shop to do the work and the cutting will cost that again. So total cost, excluding epoxy glue, for the wood components will equate to some US$860. For that amount you will end up with the following:

The prepared wooden components should amount to around US$860

This does still exclude the thinner sheeting for covering the frame. Also note the bits at the back are only temporary jig supports for frames 12 and 12a. They get removed after gluing up so that once covered, the fuselage will look like this:

So this week we will be ordering the plywood from a local timber shop and have it delivered to the routing shop. Hopefully some of the routing will also start. We will provide pictures as we go along.

And yes, you guessed it, in the background we will continue numbering! 😅

Great progress with FlyingIron Simulations Spitfire LF Mk.IX!

The design collaboration with FlyingIron Simulations is going very well! They have been making great progress with their Spitfire Mk.IX for X-Plane 11! I have attached some screen-captures from my testwork, this is version 0.7Alpha. Even at this early stage the flight characteristics are superb, while the graphics model looks fantastic.

This model will work hand in hand with our simpit, so now there are two different simulators which will provide absolute realism and accuracy in VR; X-Plane and DCS World!

The numbering shall continue until morale improves!

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.

Screenshot of the numbering in progress

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.

The HFS Spitfire MkIX high level Assembly Numbers

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.

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!

First (F)light

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.

Flight Lieutenant Brian Kingcome (left), commanding officer of No. 92 Squadron Royal Air Force and his wingman, Flying Officer Geoffrey Wellum, next to a Supermarine Spitfire at RAF Biggin Hill, Kent, 1941 (From and IWM, Public Domain)


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.

An extract of all the cockpit control components, 75 in total. Only the windscreen de-ice pump is non-functional 🙂

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!

Covered in Glory!

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
The instrument panel is now populated with tiny screws

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!

The fuselage is now beautifully covered in 0.5mm aluminium plate
All the Intercostals are now in place

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

Aileron Force Feedback Design

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.

Spitfire aileron forces as recorded during NACA tests (1942) 

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.

Flight controls complete – elevator, rudders and aileron

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.

Mechanism in port wingroot

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 aileron force feedback is coupled to the same actuator used for the rudder and the mechanisms have been moved down into the fuselage underpan

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.)

Flight controls with aileron force springs and pulleys in port wing root

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.

Ellipsoid beauty and cradles

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 Cradle

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.

Plan view showing the fillets and wing root walkway

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.

Wing roots will contain the aileron force feedback mechanism

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.

The sensuous curves of the wing roots, fillets and belly

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.

View from below showing the support box

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.

The removable fuselage cradle

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.