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Mission Statement 

The purpose of FLAPS-2-APPROACH is two-fold:  To document the construction of a Boeing 737 flight simulator, and to act as a platform to share aviation-related articles pertaining to the Boeing 737; thereby, providing a source of inspiration and reference to like-minded individuals.

I am not a professional journalist.  Writing for a cross section of readers from differing cultures and languages with varying degrees of technical ability, can at times be challenging. I hope there are not too many spelling and grammatical mistakes.

 

Note:   I have NO affiliation with ANY manufacturer or reseller.  All reviews and content are 'frank and fearless' - I tell it as I see it.  Do not complain if you do not like what you read.

I use the words 'modules & panels' and 'CDU & FMC' interchangeably.  The definition of the acronym 'OEM' is Original Equipment Manufacturer (aka real aicraft part).

 

All funds are used to offset the cost of server and website hosting (Thank You...)

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Journal Archive (Newest First)

Entries in Flight Simulator (58)

Wednesday
Nov132013

B737 Throttle Quadrant - Flaps UP to 40; Conversion and Use

This post examines the flaps lever on the refurbished B737 throttle and how it was converted to flight simulator use..

Flaps are used to slow the aircraft by creating drag, and to apply positive lift during takeoff.  The flaps lever is located on the First Officer’s side of the throttle quadrant. 

Subsequent movement of the flaps lever is indicated by illumination of the Le Flaps Transit and Le Flaps EXT lights located on the Main Instrument Panel (MIP), movement of a needle in the flaps gauge, a change of indication in the Primary Flight Display (PFD) and illumination of the Leading Edge Device (LED) panel located on the aft overhead panel. 

There are other “less obvious” indicators, but this is not the direction of his post.

The flaps lever is an integral part of the throttle unit.  Ensuring it operates correctly and with accuracy is important.

Safety Features

Newcomers to an OEM throttle quadrant are often surprised at how difficult it is to manipulate the flaps lever; it isn't a simple pull or push of a lever - there is a reason for this. 

When flaps are extended, especially at slow air speeds the flight dynamics of the aircraft are altered.  To protect against accidental flap extension, Boeing has designed the flaps lever so that a flight crew has to physically lift the lever before moving the lever to the required flap setting.  

LEFT:  Two flap gates are observed - Flaps 1 and 15 (click for larger view).

Further safety has been designed into the system by having flaps 1 and flaps 15 guarded by a flaps gate.  The gate prevents straight-through movement of the flaps lever beyond flaps 1 and 15.  The  pilot must actually lift, push and drag the lever through the gate to the next setting.

It takes a short time to become accustomed to how to move the lever for smooth operation.

Traditional Approach used in Flaps Conversion

In most throttle conversions, a single potentiometer is used and the flaps are calibrated directly through FSUPIC.  A linear rod is attached to the potentiometer and then to the lower end of the flaps lever.  When the flaps lever is moved, the rod is moved forward or aft causing the potentiometer to turn to a defined and pre-calibrated position.  The analogue movement of the rod is converted to a digital signal that can be read by Flight Simulator.

In such a conversion, it’s important to ensure that the physical position of the flaps lever matches the flaps position used in Flight Simulator and in the flaps gauge.  It’s also vital that flaps are calibrated to ensure accurate operation.

The benefits of using this traditional method are that it’s “tried and true”, inexpensive and relatively easy to implement.  Calibration is the major key; however, using FSUPIC can be troublesome and time consuming, although once calibrated everything should operate reasonably well.  

Potentiometers - Accuracy and Longevity

Potentiometers came in a variety of sizes with differing throw values.  A throw is the length of movement that a potentiometer will allow a linear rod to move.  The larger the potentiometer the more throw allowed.  The potentiometer for the flaps must fit within the throttle unit beneath the flaps mechanism in a relatively small space.  Unfortunately, with Boeing 737 late model throttle’s there is minimal room to allow a larger than 60mm potentiometer to be installed.  Using a 60 mm potentiometer means that the device has a minimal throw.

This throw, if lucky, can be stretched to cater from flaps 0 to flaps 40, but only after facetiously calibrating with FSUPIC.  More often than not,  the throw will only reach flaps 1 or flaps 30.  Often this lack of throw goes unnoticed and many virtual pilots select flaps 40 believing they actually have flaps 40, but in reality it is flaps 30.

Longevity is another more minor issue when using potentiometers.  Most potentiometers have a +- tolerance during manufacture, are made cheaply and depending upon the type selected are open to contamination from dust and debris.  Dust on a potentimeter can affect the accurancy of the unit. At the very least, maintenance is required if the potentiometer is located in a dusty area.

Several Ways to Skin a Cat.....

To solve these potential problems two methods were assessed.  The first was using two micro- buttons at each end of the linear rod that connects the flaps lever with the potentiometer.  These buttons can be assigned directly with FSUPIC to flaps UP and flaps 40.  This theoretically would solve the shortness of throw experienced with traditional conversion and calibration.  Flaps UP and 40 are controlled by micro-buttons and everything in-between is calibrated within FSUPIC.

Micro-buttons

The second method is to replace the potentiometer with micro-buttons; thereby,  rectifying the issue of minimal throw.  Replacement will also alleviate the chance of a potentiometer being inaccurate, remove any chance of contamination, and also remove the tedious task of calibrating flaps in FSUPIC.   

LEFT:  Working through an issue with the Flaps 5 micro button, custom VGA cable and PoKeys card (see below) - it's not all fun.  Chasing problems can be frustrating and very time consuming.

The use of micro-buttons to control flaps movement is relatively novel, but the potential benefits of implementing this into the throttle unit could not be overlooked; therefore, it was decided to use this method.

Problems with Micro-buttons - Design of Lower Flaps Arc Plate (LFAP)

The first initial problem encountered is that micro-buttons are small, delicate and can be easily damaged if mounted directly onto the metal flaps arc.  Manipulating the flaps lever requires considerable pressure to pull, drag and drop the lever into the correct flaps detent position. Clearly, mounting the buttons on top of the metal flaps arc for direct contact with the flaps lever was not feasible.

After much thought, it was decided to fabricate from aluminum, a plate that replicated the arc that the flaps lever moves over.  This plate has been called the Lower Flaps Arc Plate (LFAP).  The micro-buttons were then strategically mounted to the plate, each buttons’ position corresponding to a flap position.  The LFAP with the mounted buttons was then mounted directly beneath the existing flap arc plate. 

Design Considerations

Before implementing a new design, considerable thought must be taken to potential problems that may arise from the design.  In the case of using micro-buttons the issue was connectivity and the possibility of a damaged or faulty button.  The LFAP can be accessed relatively easily by removing the First Officer's side panel which allows access to the plate from behind the trim wheel.

Half-moon Provides Accuracy, Reliability and Repeatability

To enable the micro-buttons to be triggered by the flaps lever, a half-moon piece of aluminum was fabricated using the same dimensions of the lower portion of the flaps lever.  One end of the "half-moon" was  curve-shaped pointing downwards. The "half-moon" was then screwed to the lower section of the flaps lever handle   

LEFT:  Rough initial sketch of half-moon showing relationship to flaps arc and micro-buttons.

When the flaps lever is dropped into a flaps detent position, the curved side touches and depresses the micro-button mounted on the lower flaps arc plate.  When the flaps lever is moved to another flaps setting, the lever is first lifted breaking contact with the button, moved to the next setting and dropped into the detent position triggering the next button and so forth.

Interface Card

A standard PoKeys 55 interface card was used to connect the outputs from the buttons to the avionics suite software.  ProSim737 software allows easy interfacing by allowing direct connection of a button to a specific flap position.  If ProSim737 is not used and the choosen avionics suite does not support direct connection, FSUPIC can be used to assign individual buttons to flap positions.  The PoKeys card is installed in the Interface Master Module (IMM).

Advantages of Micro-buttons - It's Worth The Effort...

The benefits of using micro-buttons cannot be underestimated. 

  • 100 % accuracy of flap movement from flaps UP to flaps 40 at all times.
  • No calibration required using FSUPIC.
  • Non-reliance on FSUPIC software as the installation is mechanical.
  • Very easy configuration of flaps UP through flaps 40 using ProSim737 software configuration.
  • Removal of the potentiometer and possible inaccuracy caused by +- variation.
  • No concern regarding possible contamination of the potentiometers.
  • Enhanced reliability of operation with no maintenance required.
  • Easy removal of the Lower Flaps Arc Plate to facilitate button replacement.

Back-up Potentiometer System

Although the use of micro-buttons is successful, I still have a potentiometer installed that can be used to operate the flaps.  The reason for installing the potentiometer was in case the micro-buttons did not work correctly; it would save time installing a replacement system.  To change from buttons to the potentiometer is as easy as disconnecting one quick release connector and reconnecting it to another.

Quick Access Mounting Plate (QAMP)

The potentiometer is mounted directly onto a custom-made aluminum plate that is attached to the inside of the throttle unit by solid thumb screws. 

The reason for the plate and screws was easy access should the potentiometer need to be cleaned or be replaced. 

To access the potentiometer requires the side inspection plate of the throttle be removed (a few screws) and then removal of the thumb screws on the access plate that allows the potentiometer to be dropped from its bracket.

Unfortunately, I failed to photograph the flaps QRMP before installation; however, its design is similar to all quick release plates used within the throttle unit.  The plates are made from aluminium and are attached to the throttle unit by thumb screws rather than nuts and bolts.  This allows for easier and faster "change out" if necessary.  The above image shows the QRMP for the throttle levers - the flaps QRMP is far smaller and thinner.

Troubleshooting

During testing a problem was observed with the micro-button for flaps 5.  For an unknown reason flaps 5 would not register correctly on the PoKeys 55 card.  After several hours troubleshooting the buttons and wiring, it was determined that the PoKeys card must have a damaged circuit or connection where they flaps 5 wire was installed to the card.

The problem turned out not to be the PoKeys card, but the Belkin USB hub installed to the Interface Master Module (IMM).  I had replaced the first hub (which I damaged) with another hub that had a lower voltage.  For some reason this lower voltage was not enough to allow operation of all the functions running from the hub. 

After replacing the hub with a higher voltage device, the issue with the flaps was immediately rectified.  Of course, this was after I spent literally hours troubleshooting flaps 5!  As stated earlier, teething issues on a new design can be frustratingly time consuming...

Acronyms and Glossary

  • Flaps Arc – A curved piece of aluminum positioned directly beneath the flaps lever and corresponds to the curvature of the light plate.
  • Lower Flaps Arc Plate (LFAP) - A curved piece of aluminium that is the same size as the flaps arc and is mounted directly beneath the flaps arc.
  • Half-Moon Pencil – a custom fabricated piece of aluminum with a curved edge at one end.  Used to depress micro-buttons on flaps arc as flaps lever is moved..
  • OEM - Original Equipment Manufacturer.
  • Quick Access Mounting Plate QAMP – Quick Access Mounting Plate for the potentiometer that is a redundancy system for flaps movement.
  • Avionics Suite - Software that interacts with Flight Simulator to control avionics, gauges, etc - ProSim737, Sim Avionics, Project Magenta, etc.
Friday
Aug162013

Wiring the Simulator - Aviation Wire

When I first began to work on my simulator, I used whatever wire was available; usually this was automotive electrical wire.  The wire was inexpensive and seemed to do the job; however, there were several shortcomings.  

To carry the appropriate amperage the wire selected was quite large in thickness; therefore, quite inflexible.  This inflexibility resulted in the wire coming loose at connections quite easily.  The thickness also made routing numerous wires quite challenging and at one stage, my simulator looked like a rat’s nest of snaking coloured wires.

After a few connection issues, I began to rethink my approach.  

I have since replaced the automotive wiring with a wire grade more suitable for the purpose.  The wire I use is aviation wire which is available in various gauges (thicknesses) and colour options.  The benefits in using this wire are it:

  • Withstands physical abuse during and after installation 
  • Has a good high and low temperature properties  
  • Is very flexible and small enough to be run in tight places
  • Can be obtained in varying gauges and colours
  • Has a high flex life  
  • Has good out-gassing characteristics
  • Has a fair cold flow property (probably not that important as the simulator is not going to altitude)

The wire can easily be obtained in rolls from supply chain stores or from e-bay.  Enter the following wire reference code into either e-bay or google:  Part Number: 22759-16-22-9; 22 AWG WHITE TEFZEL WIRE.

Please note, this is the wire I use (and many other builders).  There is a wide variety of wire available in the market that is suitable for building, so don't become overly concerned if you've already used a different type of wire.  The main point to remember is that wire is rated to the application and voltages your intending to use.  The wire mentioned is ideal for all wiring requirements of the simulator with the exception of very high voltage requirements.  High voltage requires a wire of lower gauge (thicker wire) to ensure minimal voltage drop over distance. 

The same type of wire as mentioned above can be purchased in differing gauges (thicknesses).  I find 22 gauge is a good overall gauge to use.  Remember that voltage (amps) is rarely being applied to the wire continuously (exception is from power supplies).

Easy Connect/Disconnect Connectors

Often there is a need to connect a piece of wire to another piece of wire or part and have the ability to be able to disconnect the wires easily and quickly.  For example, often panels must be removed from the center pedestal; having the ability to disconnect wires easily allows complete removal of the item without destroying the attachment wires!

There are dozens of connectors available for joining or extending wires – some are better than others.

I use (where possible and when voltage/amp requirements dictate) JR servo wire security clips.  These little clips allow three wires to enter to either side of the connection, are made from heavy duty plastic, and have a guaranteed clipping mechanism that will not unplug itself.  Search the Internet for JR extension servo clips. 

For applications requiring more than three wires, or higher voltage/amps, I use a high quality terminal block, Canon style plug or a D-Sub plug.  The later two requiring each wire to be very carefully soldered into the appropriate wire reciprocal in the plug.  I also use Mylar quick release plugs for some applications.

All other wires that require a permanent connection are usually soldered together with wire shrink wrap.  Soldering always provides the best connection.

Friday
Jun142013

Genuine B737 Forward & Aft Overhead Panels Purchased

For some time I’ve been debating whether to use a reproduction or genuine forward and aft overhead panel.  I have been favouring a genuine panel as this is in line with using genuine parts in the simulator, however, the overhead is a complicated piece of kit and ensuring complete functionality would be  a challenge.

RIGHT:  Forward Overhead Panel.  The centre panels will be replaced to conform to a 737 NG.  Panel was removed from a United Airlines 737-300 aircraft.

Certainly, using an overhead panel made by Flight Deck Solutions (FDS) or Fly Engravity is an easier option, however, their overheads use flight illusion gauges and I don’t want to go down this route.  After seeing and using genuine gauges in the MIP I can see a huge difference in quality and aesthetics between a genuine gauge and those produced by flight illusion.  

Genuine B737 Overhead Panel Purchased

My decision was made for me when I was told a forward and aft overhead had become available from a recent 737 pull down.  Rather than remain indecisive, I thought I’d jump in “boots and all” and purchase it.  The two overhead panels have come from B737-300 and include the frames, DZUS rails, center panels, engine starter switches, landing gear toggles and various other knobs and toggles.

I’m impressed at the condition of the panels; usually when panels are removed from an aircraft in a tear down yard there is little care given and the frames become scratched, dented or damaged in some way.  The frames I have purchased appear to be in relatively good condition.  

Cole Switches

I was very lucky that the two engine starter switches (Cole switches) were included.  These switches are made to exacting requirements and use a solenoid mechanism.  Purchasing Cole switches individually is quite expensive, so I'm pleased they were not striped from the overhead.

LEFT:  Difficult to find operating Cole switches are used on all Boeing airframes from the 727 through to the NG and I believe NGX (click to enlarge).

Panels and Back Lighting

When I began to construct the simulator in mid 2011, I was adamant that back lighting should match that of the MIP, throttle quadrant and center pedestal.  My opinion has altered since then and now I am happy to have a mix of IBL bulb and LED lighting (within reason).  I believe it was around 2006 that Boeing began to replace bulb-generated back lighting with LEDS.  Certainly, the latest made Boeing now uses LEDS for IBL and older airframes, with replacement parts will present with a mix of lighting types. 

The use of bulbs in the overhead uses a lot of power and generates considerable heat; using LEDS minimises power consumption and produces less heat.  If the LEDS are installed correctly, their resultant light is very similar to that of bulbs and the illuminance observed in the real aircraft.

Ultimately the back lighting will be dependent on whether I decide to use older style genuine Boeing panels or reproduction panels.

Realism & Authenticity - How Far Do You Go

Some flight deck builders go to extremes to ensure their flight decks replicate exactly what is seen in the real aircraft and while this is admirable, this is not the route I am 'religiously' going to travel.  There has to be compromise between replicating something exactly and having a functional flight simulator.

The end product will  be a combination of genuine (OEM) and reproduction parts - mostly OEM.

Furthermore, serious thought must also be given to how the overhead is going to be installed to the simulator; whether it be to a shell, such as produced by FDS or to a custom-made roll cage assembly.

I'll keep the Blog updated as parts are found and the overhead is developed.

To see additional images of the "naked" overhead, navigate to the image gallery.

  • I must apologise for the poor resolution of these images; they were supplied by the vendor. Currently the overhead is still located in the US.  In time better quality images will be uploaded.
Saturday
Dec012012

Digital Chronograph Running ProSim737 Software

The Main Instrument Panel (MIP), unless a special order is made, usually will not include a chronograph.  Depending upon the MIP manufacturer, the MIP may have a cut out for the chronograph, a facsimile of a chronograph or just a bezel. 

The Next Generation aircraft use digital and mechanical chronographs.  However, for the most part all late model Next Generation airframes use digital chronographs.  The classic series airframes usually use (unless retrofitted) mechanical chronographs.

After Market Chronographs

There are several after-market chronographs that can be purchased.  SISMO Solicones produce a mechanical type that replicates the real world counterpart quite well, despite the awful orange-coloured backlighting.  Flight Illusion produces a quality instrument as does Flight Deck Solutions (FDS).  FDS replicate the digital chronograph. 

No matter which type you decide, be prepared to shell out 250 plus Euro per chronograph; for an item rarely used it's quite a financial outlay.

Whilst converting a genuine B737 mechanical chronometer is a valid option, finding one is difficult, as airlines frequently keep chronographs in service for as long as possible.  Converting a digital chronograph is an option, however, the initial price of the item and then conversion make this an expensive excercise.

Another option is to use a virtual chronometer (as included with Sim Avionics and ProSim737).

ProSim737 Virtual Chronograph

ProSim737 as part of their avionics suite have available a virtual chronometer.

LEFT:  Screen capture of ProSim737 chronograph.  ProSim737 have a Chronograph that can be used for the Captain and First Officer side of the MIP.

The display is very crisp, the size is accurate (1:1 ratio), and the software allows complete functionality of the chronograph. 

To use the virtual version a small computer screen is needed on which is displayed the virtual chronograph.

Chronograph

A friend of mine indicated that he wanted to make a chronograph for the simulator and use the virtual ProSim737 display.  He also wanted to incorporate the four setting buttons and have them fully functional. 

The components needed to complete the project are:

(i)    A small TFT LCD screen (purchased from e-bay);

(ii)    A standard Pokey interface card;

(iii)   Several LEDS; and,

(iv)   Four minature tactile switches and electrical wire. 

The screen used was 5.0" TFT LCD Module with a Dual AV / VGA Board 800x480 with a 40 Pin LED Backlight. 

The screen was small enough that it just covered the circular hole of the cut out in the FDS MIP.  The TFT LCD screen uses a standard VGA connector cable, 12 Volt power supply and a USB cable to connect the POKEY card to the computer.  

Two-part Fabrication

FDS supply with their MIP a bezel with four solid plastic and non-functional buttons.  The bezel does not support direct backlighting, nor does it have enough space for tactile switches or wiring. 

LEFT: The holes in the box provide ventilation for the Pokeys card.  The only portion of the box that is visible from the front of the MIP is the bezel and four buttons.

Therefore, the bezel must be modified to accommodate the wiring for the switches and LED illuminated backlighting. The easiest way to approach this modification is to use a Dremel rotary tool with a 9902 Tungsten Carbide Cutter.

Place the bezel on a hard surface using a towel to avoid scratching and damaging the bezel.  Then, with 'surgical' accuracy and steady hands carve out several channels (groves) at the rear of the bezel.  The channels enable placement of the miniature tactile switches, small LEDS and wiring. 

Space is at a premium, and to gain addition real estate, the LEDS were shaved to remove excess material.  This enabled the LEDS to fit into the excavated groove on the bezel.  Be very careful when using the carbide cutter to not punch out onto the other side of the bezel. 

The four solid plastic front buttons on the bezel were carefully removed.  each button was attached to the front of a miniature tactile switch, and using common ground leads, connected with the Pokey card.  26/28 AWG wire was used to connect the switches to the interface card.

Box Fabrication

A small box needs to be fabricated to house the Pokey card.  The size of the box is controlled by the size of interface card used and the length and width of the LCD screen. 

LEFT:  The box is not seen as it's attached to the rear of the MIP.  My friend's humour - several warning signs suggesting that I not tamper with his creation :)

The material used to fabricate the box is plastic signage card (corflex); real estate agencies often use this type of sign.  The main advantage of this material is that it’s not difficult to find and it's easy to cut, bend, and glue together with a glue gun.    

After the Pokey card is installed to the inside of the box, and the LCD screen attached to the front edge, the bezel needs to be secured to the front of the LCD screen.  The best method to attach the screen and bezel is to use either glue or tape. 

A hole will need to be made in the rear of the box to enable the fitment of the USB and VGA connectors.    Small holes punched into the side of the container ensure the LCD screen and Pokey card do not overheat.  To conform to standard colours, the box is painted in Boeing grey.

LED Backlighting

Careful examination of the backlighting will show that the light coverage is not quite 100%.  There are two reasons as for this.

(i)    There is limited space behind the bezel to accommodate the wiring and the LEDS; and,

(ii)   The material that FDS has used to construct the bezel is opaque.  The only way to alleviate this is to replace the stock bezel with another made from a transparent material.

Potential Problem

An issue can be the limited space to mount a a small LCD screen behind the MIP.  If you're forced to use a smaller screen, the outcome will be that you may see the screen edges within the bezel.  For the most part this is not an issue, if you ensure the desktop display is set to black.  Remember, you are looking at the chronograph from a set distance (from the pilot seat) and not close up.

ProSim737 Virtual Chronograph (position and set-up)

This task is straightforward and follows the same method used to install and position the PFD, ND and EICAS displays.  

Open ProSim737’s avionics suite and select the virtual chronograph from the static gauges:  resize and position the display to ensure the chronograph conforms to the size of the bezel.  To configure the buttons on the bezel, so that ProSim737 recognizes them with the correct function, open the ProSim737 configuration screen and configure the appropriate buttons from the switches menu (config/switches).

The four functions the buttons are responsible for are:

(i)    Chronograph start;

(ii)    Set time and date;

(iii)   Expired Time (ET) and Reset; and,

(iv)   +-

NOTE:  The above functions differ slightly between the panel and the virtual chronograph in use.

Chronograph Operation and Additional Configuration

The chronograph can be initiated (started) by either depressing the CHR button on the top left of the clock, or by depressing the CLOCK button located on the glarewing of the MIP. 

LEFT:  Captain-side CLOCK start button (FDS MIP).

Configuration

Connecting the CLOCK button to the chronograph start (CHR) function is straightforward.

Connect the two wires from the Captain-side clock button to the appropriate interface card and configure in the switches tab of ProSim737 (config/switches/CAPT CHR).

The same should be done with the First Officer side CLOCK button and chronograph, however, ensure you select the FO CHR function in switches to be done for the First Officer side chronometer if fitted.

If configured correctly, one press of the CLOCK button will start the chronograph, a second press will stop the chronograph, and a third press will reset the chronometer to zero.

Video

Here is a short video (filmed at night) showing the new chronograph running the virtual ProSim737 software.

 

Sunday
Nov252012

Modular Floor Structure / Base Platform Installed

Although it has taken longer than anticipated, the second platform to replace the platform made from wood and MDF fibreboard has been completed. 

The new design is constructed from aluminium flat tubing, is modular, and incorporates the mechanical hardware needed for operation of the OEM B737 control columns.  Click images for larger view.

LEFT:  Portion of floor structure showing modules bolted together with control columns and rudder pedals installed to structure.

The structure comprises two main sections - the modular floor structure, and floor (called the base platform).

The modular design of the platform, which in addition to allowing easy disassembly and transport (if required), also allows the platform to be increased in size by adding further modules.  For instance, if I decide to add an instructor station in the future it will be straightforward to manufacture another module and bolt it to the existing framework.  The hollow underneath section also provides an ideal area for the hidden storage of wires, power boards, and other pieces of necessary equipment such as external speakers and sound systems.

LEFT: Centre platform with ABS plastic floor structure attached. Note the shiny appearance.  This was later removed by painting. (click image for larger view).

Access to the underside of the base platform (floor) is via several well-positioned observation hartches.  Removal of a hatch enables access to whatever is beneath the floor.The platform comprises ten modules which are bolted together at strategic locations to ensure the structure is rigid, strong and sturdy.  Each module has several cross stays that have been welded in place ensuring adequate support for the weight which will be placed on the platform (Weber seats, MIP, throttle unit and people).

LEFT:  Two aft modules with flooring fitted, rudder pedals in background on forward command module.

The first three modules, which I call the command module, have been constructed as one unit and house the rudder pedals, control columns and incorporate the duel linkage rods and other mechanical hardware for control column and rudder pedal operation.  Although this unit can be separated into the three modules (by removing the attachment bolts, springs and linkage rods),

it’s best to leave them attached, as removing the steering mechanism and associated equipment is a complicated and timely operation.

Behind the forward command module are three secondary modules to allow attachment of the two Weber seats and throttle quadrant.  The MIP is attached to two smaller and narrower modules bolted at the front of the command module; whilst at each side two longer and narrow modules provide side support. 

LEFT:  Half circle flange and seal around control column and drill holes through floor that match corresponding hole in aluminium framework.  Bolts have been used to secure Weber seats.  In the second picture of this series, you can see the claw feet secured by four bolts through the flooring to the support beneath.

Platform Height and Dimensions

The height of the platform measures 16 cm (6.3 inches) and the total weight, including the two rudder pedals, internal mechanisms and control columns is approximately 160 kilograms (353 pounds).  At this weight, it certainly will not be sliding anywhere.

The platform is not a full size platform as space availability at the current time is limited, however, if and when I wish to move into a full size platform, it will be easy to incorporate and bolt additional correctly sized modules to the existing structure.

Installing Weber Seats

The Weber seats need additional support as seat movement can generate stress at the connection point of the claw feet and floor.  To ensure the seats fitted securely and any stress of seat movement was absorbed by the platform and not just the floor structure, the claw feet bolt directly through the floor to the aluminium tubing structure.  Therefore, the platform absorbs the stress when the seats are moved rather than the flooring.

Platform Floor - ABS Plastic

In the real aircraft the floor is made from pressed aluminum which is studded (rivets) in strategic locations to ensure it is solidly fixed.  Various hatches (hinged and otherwise) are present in certain areas to facilitate access to areas beneath the sheeting.

Builders use many different products for the floor, ranging from MDF fibreboard, ply and aluminium to tin or plastic.  I was intending to use thin aluminium sheeting as a platform floor, however, when I discovered the price I decided to use something less conventional.

A supply of heavy duty ABS plastic was readily available; the advantage of this material being it doesn’t require painting as it’s already coloured Boeing grey, is easy to cut and work with, is of a thickness and weight that can withstand the intended weight and finally, doesn’t flex.  Rather than use one large sheet of board for the platform cover, which would be unmanageable, the sheet has been cut to fit each corresponding module.  The sheets are attached to the aluminium tubing of the module by normal stainless screws. If the material doesn’t hold up to my expectations, I’ll replace it with aluminium or quality ply board. 

Although the ABS plastic is coloured grey, I found it to be too shinny in appearance.  Preparing the ABS plastic for painting was straightforward and entailed thoroughly cleaning the plastic with detergent to remove any residue oil.  Then the plastic was lightly scoured using a low grade sandpaper.  This creates a suitable texture for the paint to adhere.  The ABS sheeting was then painted with one coast of epoxy plastic primer and two coats of matt Boeing grey. 

The ABS plastic and paint has held up to use very well.  Even after scuffing, and moving the throttle quadrant onto and off the floor several times the paint and plastic has not been damaged.

One downside of using ABS plastic can be electrostatic discharge.  If you wear socks on the platform and rub your feet on the ABS plastic a charge can build-up.  I have yet to discover a way to stop this from occurring (other than wearing shoes).

Perhaps I will upgrade the ABS floor at some stage to a full aluminium floor, but at the moment I am more than content with the use of ABS plastic.

Installing the Control Columns, Rudder Pedals and Column Flange

The floor has been cut and the hole shaped to accommodate the control columns and rudder pedals.  The various linkage rods and internal mechanisms have either been either bolted or welded directly to the lower platform superstructure.

LEFT:  Tyre inner tube cut and stretched to fit beneath control column flange.  The overlapping area of rubber tube sits over the bulbous part of the control column lever with the floor.

The half circle flange (or whatever Boeing call it) that surrounds each control column on the floor was constructed from light metal.  To replicate the rubber-like seal that is often observed above at the lower end of each control column, a piece of recycled inner tyre tube was used.  The rubber was cut and easily stretched to fit beneath the half circle flange. 

The installation of the control columns to the platform structure has been addressed in a separate article.

The addition of a forward module to the platform is discussed in this article.

The Main Instrument Panel (MIP) is secured to the platform by several bolts strategically placed on the MIP.

Computer and Sound System Installation

The two computers that are needed to operate the simulator will be positioned at the front of the platform where access is relatively easy to both power supplies and the MIP.  The sound system, which comprises three speakers and a sub-woofer speaker, will be placed directly beneath the floor structure. In the first picture, you can just see the sub-woofer speaker towards the end of the platform.

New Platform Verses Former Platform

The structure of the first platform was from wood, and access to the underside of the platform from the side was next to impossible.  The floor was made from two large sheets MDF fibreboard and although sealed and painted, still appeared to release gases (MDF fibreboard releases gas and requires sealing for indoor use).  The structure and flooring was very solid, but access to anything beneath the floor (maintenance) was difficult. 

Too view additional pictures navigate to the image gallery

BELOW:  Diagram layout of modular design.

 

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