• Fighter Plane MIP Design and Layout

    MyCockpit ģ Presents "Mikes Tips" by Mike Powell

    Fighter Plane MIP Design and Layout

    The main instrument panel is in the primary field of view. When it looks real the sense of immersion is deeper and the flight sim experience is better.

    Of course, building a realistic instrument panel is not without its challenges, particularly so when contemporary fighter aircraft are considered. Dimensions are probably a mystery, and the physical structure may appear impossible to duplicate.
    Case in point: the A-10C Thunderbolt II, aka ďWarthogĒ. We can find pictures of the cockpit, but no actual engineering dimensions. The main instrument panel is so heavily populated that thereís apparently no room for supporting structure to hold the instruments. On top of that, the panel isnít even flat; itís stepped.

    Itís a nice looking cockpit, and thereíre high quality flight sim products based on the plane, but how would you layout and build a panel like this?

    (Picture copyright Keith Lafaille 2011)

    Collecting information is a great beginning. Pictures. Lots of pictures, so visit every aviation-related photo site you can think of. And donít bypass the flight sim community sites. If youíre interested in a particular aircraft, thereís a good chance someone else is too. Maybe they have pictures. Perhaps they posted them. Take a look through any documentation of flight sim applications for your chosen plane. Track down pilot operating manuals and maintenance manuals for the real aircraft. Look for PR and marketing literature. In short, collect as much information from as many sources as you can find.

    Next come dimensions. There are a few photo sets taken by sim enthusiasts that include a tape measure in the pictures. If youíre lucky enough to have found such a set for your project plane, so much the better. If not, youíve already got something almost as good, the instruments in the pictures.

    Instruments are made in standard sizes, and those sizes are documented in standards you can download for free.

    For example:

    MS27560, 2-3/8 Square Instrument Case, Standard Dimensions For

    MS33545, Case Ė Instrument, 5 & 5-1/4, Standard Dimensions For

    MS33549, Case Ė Instrument, 2-3/4 Dial, With Sump, Standard Dimensions For

    MS33556, Housing, Indicator (for a nominal 3Ē display like the RWR CRT display)

    MS33638, Cases, Instrument, Flange-Mounted, Aircraft (covers 1-1/2, 2, & 3 inch instruments)

    MS33639, Cases, Instrument, Clamp-Mounted, Aircraft (covers 1, 1-1/2, 2, & 3-1/4 inch instruments)

    MIL-I-83034A, Military Specification, Indicator, Horizontal Situation AQU-6/A

    MIL-I-27193C, Military Specification, Indicator, Attitude ARU-2B/A

    MIL-I-83152B, Military Specification, Indicator, Indicated Airspeed AVU-22/A

    MIL-A-83419C, Military Specification, Altimeter, Servo Controlled, Automatic Pressure Standoff

    Many standards and specifications are hosted on sites like www.assistdocs.com, www.everyspec.com and www.liberatedmanuals.com. You might also locate these sorts of documents by a simple web search, or by posting a query on a flight sim forum.

    Using an inexpensive drawing application like TurboCAD or a free one like DoubleCAD XT or Google SketchUp, draw dimensionally accurate outlines for each of the instruments on the panel. Arrange these outlines on a composite drawing using your panel picture collection as your guide.

    There will be a few things missing from your drawing. In the case of the Warthog MIP, youíll notice from the first photo that there are a few sub-panels, and a pair of multi-function color displays (MFCDs) there that we donít have dimensions for. However, we can judge the relative proportions from the pictures and make workable estimates. Unless you have surplus gear youíre adding to the project (in which case you can measure that gear), absolute dimensional accuracy is not needed.

    Hereís the sort of composite drawing you might create:

    You may find that you need to change the layout. The goal is not a picture perfect copy of an actual cockpit; itís the experience the simulator affords. Sometimes reality intrudes, and accommodations should be made.

    The MFCD is a case in point. The real unit uses a nominal 5 inch square display. If you duplicate the real MFCD bezel you wonít find an affordable commercial LCD to fit. A 5.6 inch LCD wonít fill the bezel display area, and while an 8.0 or 8.4 inch display will, both are too large to fit behind a dimensionally accurate MIP.

    Itís more important to the simulator experience to be guided by the dimensions and achieve a finished appearance, than it is to be limited by the dimensions and have a distracting, hacked-together appearance.

    Once the panel layout and dimensions are decided upon, the question of how to build it surfaces. The Warthog panel is challenging because it isnít flat, and because the closely packed instruments leave little room for supporting structure.

    One solution is to follow the lead of the real flight hardware. The actual MIP structure is a lattice of metal bars. The instruments, MFCDs, and sub-panels all mount to this structure with screws. If you want a very realistic appearing panel, you can start by making a similar lattice structure.

    The drawing used to develop instrument placements and panel dimensions can be put to use for designing the lattice. Add a lattice of bars to the drawing between instruments, sub-panels, and the MFCDs. Using bars of differing widths provides the means of creating the stepped panel structure like this:

    This structure can be build from 1/8 inch thick aluminum bars in widths ranging from 1 to 3 inches. While it would be nice to have a machine shop and a TIG welding rig, you can build this using basic hand tools and some good quality epoxy. The joints should be reinforced with aluminum angle. Threaded spacers can be glued into the corners to provide the attachment points for the instruments, MFCDs, and sub-panels. Itís time consuming, but results in a realistic MIP structure.

    A few notes:

    Epoxy is capable of forming a strong bond with aluminum, but only if the gluing surfaces are properly prepared. Thoroughly cleaning and roughening the surfaces with 100 grit sandpaper is critical.

    Aluminum bar is often available from larger home building supply stores, but prices can be much better from on line sources (like On Line Metals) even considering shipping.

    Mike Powell, author of

    Building Recreational Flight Simulators

    Building Simulated Aircraft Instrumentation
    , and

    Building Simulator Display Systems
    . (A work in progress)