I just posted a new video presentation about my flight simulator. It’s about 45 minutes long and shared for those of you interested learning more about the project in greater detail.
I’ve given this presentation each of the past two years at EAA Airventure in Oshkosh, WI. I hope you all enjoy it and I welcome your comments and questions.
Having finished the bulk of the avionics work, it was time to focus on installing the various trim pieces, mostly plastic, that finish off the cockpit. In order to have the maximum amount of working room, I decided to complete most of this task prior to installing seats and the circuit breaker structures that make up the back wall of the cockpit.
My cockpit sat in the boneyard for about two years before I bought it on eBay in 2011. All of the cockpit windows were certainly removed early on, because they are very expensive parts and the market for serviceable used units is robust. The result of this was that the remaining parts of my cockpit were exposed to the elements for the three year interval after the airplane landed there after a brief flight from Chicago in 2008. The dust and rain that entered the cockpit caused a number of the fasteners holding the trim in place to become seriously stuck. Once again PB penetrating catalyst came to the rescue, but not all of the fasteners were easily removed. Many required turning with locking pliers (eg vice-grips), and the most stubborn ones required drilling out. Just removing the trim took several months back when the airplane was still in the hangar.
As this trim was 25 years old, many of the plastic pieces were very brittle, and some pieces were unavoidably damaged during removal. Several broken pieces needed mending, which I did by backing the pieces with fiberglass, then filling in the cracks with 3M flowable finishing glaze and sanding before painting.
The only unpainted metal parts were the rudder skids, which were easily polished with an orbital buffer and some 3M rubbing compound. The corrugated metal floor pieces outboard of the seat J-rails were stripped and painted.
The trim pieces as well as the screw heads were painted according to location. My cockpit is a classic 737 model, but I was building a 737 NG model, so I painted the lower parts of the trim in a light gray primer obtained at Home Depot. The upper pieces were painted in a medium gray primer. After applying two coats, I applied a clear matte finish on top of each of these to eliminate the sandpaper texture of the primer.
The reassembly process was a bit of a jigsaw puzzle, made easier by the mounting points left behind on the OEM shell. The basic installation scheme is to start low and aft and work your way forward and to the top, as many of the pieces overlap in a specific configuration. Straight awls are helpful for lining up holes to the nutplates. After the trim pieces were installed, various accessories were installed on top, including cupholders, oxygen mask storage boxes, and ashtrays. Believe it or not, when this airplane came off the assembly line in 1988 the cockpit was equipped with ashtrays. Of course this is now a non-smoking cockpit. At some point in the future I will replace the ashtrays with custom sheet metal pieces with USB connections to each of the computers running the simulation, but until then the original (very clean) ashtrays remain in their positions.
If you are attending Airventure 2017 in Oshkosh, WI, be sure to make plans to attend my live presentation on my simulator project in Forum 6 on Thursday, July 27 at 2:30pm. For the true airplane enthusiast, there is no better airshow to attend. I look forward to meeting many of you there!
One of the last major avionics projects prior to closing up the cockpit with trim was the installation of the avionics pedestal. This piece is screwed to the floor and has Dzus rails for mounting various avionics including the radio control heads.
The pedestal itself is a Boeing OEM unit that was installed in the cockpit I originally bought in 2011. Removing the pedestal required a great deal of patience as the screws holding it in place were exposed to the elements for a couple of years while the cockpit was waiting in the boneyard for me to rescue it. PB penetrating catalyst was essential to this task. I stripped the pedestal and refinished it with a self-levelling compound made by 3M. I then painted the unit in the style of an NG model 737, with off white for the body and gray trim around the top. Clear matte spray finish makes for a better appearance and covers up the sandpaper texture of the primer.
The power and USB cables were previously run under the floor back when it was still in vertical position. I chose a combo 12v/5v power supply to provide 12v to the FDS-SYS3 card and 5v for the lighting. This power supply also wound up being used for two USB hubs that wound up inside the pedestal. The backlighting is on a FDS-IBL-DIST-DIM with a FDS-IBL-DIST-EXP card. A 24v power supply was added later when I finished interfacing an OEM fire panel.
After screwing the pedestal back onto the OEM nutplates, I connected the various pedestal modules one at a time. My pedestal has 2x multicom units, 2x NAV radio heads, 2x dummy audio panels, one transponder control, a cargo fire panel, a dummy radar control panel, aileron/rudder trim panel, a door access panel, and a lighting control panel.
Having finished the bulk of the avionics installation, it was time to think about installing the plastic trim pieces in the cockpit. Before proceeding with trim installation, I had a few remaining tasks. In this post I will describe how I interfaced a Boeing OEM nose tiller.
When I purchased my cockpit in 2011, the complete nose wheel tiller mechanism was present. It worked fine, but was in need of cosmetic improvements. I was looking for a way to refinish the wheel itself, which is covered with a very thick, chip resistant coating, when a new-old-stock (NOS) OEM unit came up for sale on eBay…$79.50 plus shipping.
Since the initial design of the Boeing 737, nose wheel steering on the ground has been augmented by a metal control wheel just to left of the Captain’s thigh. On the ground, the airplane can be steered by differential thrust on the engines, but for fine control, especially at low speeds, the steering tiller is used to direct the nose wheel. Larger Boeing aircraft have this control duplicated for the FO, but in the 737, only one tiller is installed on the Captain’s side. In the actual aircraft, the tiller mechanism is connected to the rudder pedal linkage under the flight deck floor via steel cables. In the interest of time I elected to implement my steering tiller as an independent unit.
I simply cut the steel cables and fitted the ends with heavy duty springs. A short piece of RC modeling rod is used to connect one spring to a Phidgets 60mm sliding potentiometer. This pot is then connected to a joystick card (eg Leo Bodnar BU0836X) and the axis is calibrated in FSUIPC. The video below shows how the RC rod is connected to the part of the spring with an amount of travel that is appropriate to the pot.
Having finished the modification of the FMS/CDU bay, I continued my top-to-bottom avionics installation. One of the most critical components, the Boeing throttle quadrant, is located just aft of the FMS/CDU bay.
The TQ I have was purchased several years ago from Art May-Alyea at Northern Flight Sim. Art has a wealth of experience converting old TQs from classic models to closely resemble those used in the NG. He completely disassembles the units, refinishes and paints all the components, installs microswitches to detect every switch position including every detent on the flap lever, then fits the assembly with motors for the trim wheels and throttle levers, as well as servos for the speed brake lever and trim indicator.
Art supplies the TQ conversion with bare wires coming out the front, and interfacing is up to the user. Full details of how I chose to complete the interface will be described in a later post, but the short version of the story is that most of the TQ is connected to a BU0836X joystick controller card from Leo Bodnar. The 12v motor driving the trim wheels are connected to a PhidgetsMotorControl HC card. The throttle levers are driven by two 12v motors fitted with slip clutches and interfaced to two Pololu Jrk 12v12 cards.
The pedestal itself is a Boeing OEM unit that came with the full cockpit I purchased from eBay in 2010. The frame was removed, fully stripped, restored and repainted in the colors of a typical NG model prior to reinstallation. All of the radios and other avionics in the pedestal were provided by FDS, and are purpose built for the simulation market. The one exception is the fire panel in the most forward part of the pedestal frame: this is a Boeing OEM unit that I reverse engineered and will describe in a future post.
Prior to proceeding with installation of the trim pieces and back wall, I spent several months checking avionics functionality to determine whether I would need to run any additional wires behind any of the panels. Access to the back of the overhead panels is fairly easy thanks to FDS mimicking the OEM design . I didn’t think of everything, but I got most of the major kinks worked out prior to proceeding with the finish work.
If you are attending Airventure 2017 in Oshkosh, WI, be sure to make plans to attend my live presentation on my simulator project in Forum 6 on Thursday, July 27 at 2:30pm. For the true airplane enthusiast, there is no better airshow to attend. I look forward to meeting many of you there!
Bad simulator blogger. Eighteen months without an update. The truth is that I’ve kept very busy working towards establishing full functionality. The sim is now operational and flying regularly. Almost everything works, and over the next few weeks I will be bringing you up to speed on everything I’ve done since my last post.
This update today concerns the FMS/CDU (Flight Management System/Control Data Unit) bay just under the main instrument panel (MIP) and forward of the throttle quadrant (TQ). As described in a previous post, the width of this bay is one of the major differences between the cockpit of a classic model 737, which I obtained in 2010, and the the NG model, which I am attempting to simulate.
As I wanted to retain the original equipment manufacturer (OEM = Boeing) rudder pedals, with their linkages and height adjustment mechanisms, I had to figure out a way to taper the FMS/CDU bay so that it remained narrow at the bottom, but was wide enough at the top to fit the two control units, as well as the lower EICAS screen. The difference in width is about 1.75 inches, with the NG model being wider. In the real airplane, the rudder pedals in the NG are more narrow to allow the overall width of the cockpit to remain the same.
My strategy was to retain the OEM frame at the bottom, and use a bay and FMS units built by Flight Deck Solutions (FDS) for the top. The OEM rudder pedals are fairly tall, and the FDS FMS units are fairly deep, having been designed to sit on an angled base when used on a desktop.
After a number of rounds of measurements, I cut off the top of the OEM base and fitted the sides with 1 inch angle aluminum. I then cut off the top of the FDS bay. I retained the interior shelf from the FDS bay and cut it so it would fit inside the OEM base, allowing a place to mount 4 interface cards, a PC power supply (to provide 5 and 12 volt power) and a USB hub. These components provide interfaces to all of the electronics for the MIP, FMS/CDU units, OEM bell/clacker box, lower EICAS screen and associated panel lighting.
The cut off top of the FDS bay was similarly fitted with 1 inch angle aluminum. As the MIP was also an FDS product, the forward edge of the FMS/CDU bay had pre-drilled holes that allowed the two components to mate up correctly. Lining up the aft edge of the FMS/CDU bay to the forward edge of the TQ required a number of dry fit adjustments prior to actually drilling holes to set the proper angle for the three screens.
After assembly, I used the OEM trim pieces to cover the aft edge of my creation. The top of the trim doesn’t quite match up to the aft edge of the FDS bay. Most visitors to the sim never notice because there are so many things to look at and explore. The rudder pedals at the most aft position (for those pilots who are most vertically challenged) clear the bottom of the cut off FDS bay by less than 1/4 inch, but there is no play in these controls as everything is firmly in place.Eventually I will fabricate some custom trim for the outside of this contraption, but for now I am very pleased with the result.
Having previously installed my original Boeing landing gear lever, I decided to remove the old, yellowed ‘large’ wheel typical of the -200, -300 and -400 models, and exchange it for a smaller one more typical of the NG series.
For the small one, I decided to use the wheel and bracket from an FDS landing gear lever that I had left over from the disassembly of their MIP. This was easily separated after removing four hex screws.
The Boeing bracket holding the wheel was riveted in place, fortunately with solid rivets instead of blind rivets, which are generally much harder to remove. I was able to quickly drill out the rivets and remove the old bracket/wheel combination .
Installing the FDS bracket/wheel required tapping some threaded holes to accept the hex screws. This was a quick modification that looks really good in the end, even if replacing the rivets with screws is not completely authentic.
Happy New Year! It’s been more than six months since my last blog entry, but I have kept very busy fitting avionics into the shell. At the beginning of this phase of the project, I had a general idea of where the various pieces (main instrument panel, mode control panel, EFIS modules, glareshield, and FMC/CDU bay) would wind up, but had to work out a large number of details about how the major components would fit together.
The dimensions of a 737NG cockpit are virtually identical to that of the classic model, with one major exception: the FMC/CDU bay of the NG model is almost two inches wider than that of the older models, to accommodate the lower EICAS screen between the two CDUs. The rudder pedal bays are slightly smaller to accommodate this change.
I had two FMC/CDU pedestals, a narrow Boeing one that came with my cockpit and a wider, NG size model made for the simulation market by Flightdeck Solutions.
The problem could not be easily solved. The FDS pedestal was too wide to fit into the available space without rubbing against the rudder pedals, and the Boeing one was too narrow to accommodate all of the components. So I decided to use the top of the FDS pedestal mated to the bottom of the Boeing unit.
I would have to be fairly precise with the cuts. The mated pieces would have to be high enough at the forward edge to meet the main instrument panel (“MIP”) at the right place, and low enough to join up with the throttle quadrant at the aft edge. Furthermore, the rudder pedals needed to be able to clear the enlarged pedestal at the aft end of their travel, and the top, FDS portion would also have to be deep enough to accommodate the FDS CDUs, which sit on wedge shaped bases to allow them to be used as freestanding units on the desktop.
My original plan was to mount the MIP first, so that I would know exactly where to mount the FDS top onto the Boeing bottom. The only problem with this was that the mode control panel (the “MCP” or autopilot control panel) and EFIS control panels needed to be mounted first so that the top of the MIP would be fitted correctly. As I plan to do for all avionics, this unit was first bench tested and fully configured prior to installation. Troubleshooting these units is so much easier before they are installed in the shell.
The FDS MCP/dual EFIS units are beautifully constructed, sturdy pieces that are faithful to the originals, with precise dimensions on the front faces. In spite of this, the units do not fit on to the Boeing mounts without significant modification. The original mounting brackets are relatively thick given the importance, weight and cantilevered configuration of the autopilot system in the real aircraft.
In order to fit the FDS units into the mounts, I cut openings in the sides of the FDS MCP. To take advantage of the Boeing angle brackets, I mounted two #10 nutplates on the inside of the MCP case to allow the mounts to be squeezed together and the screws attached, all without opening the MCP case. For this application I chose an aerospace fastener made by ClickBond, a brilliant, mil-spec system that allows the nutplates to be attached with a two part epoxy, thus avoiding riveting. I also drilled holes in the FDS shelf that holds the MCP and dual EFIS units. I used two large clamps to hold the assembly together while inserting screws from the bottom. Each screw went through the FDS shelf, then through the Boeing angle bracket, and finally into the nutplate mounted on the inside of the FDS MCP.
In each of the FDS EFIS units I mounted two additional floating nutplates, used to fix the units into proper position on the shelf. After mounting these units, I was able fit the FDS glare wings and glareshield and the result was a very clean install that looks great.
The MIP as originally received from FDS was assembled in their factory as a complete unit and fully wired, including the glareshield, MCP/dual EFIS units, MIP lower EICAS screen and FMS/CDU bay. It was also designed to be a freestanding unit, with easy access to the backside.
In order to be able to handle the MIP frame easily, I would need to strip all the avionics out. This required making the avionics much more modular than they came from the factory. I repurposed several AMP cannon plugs salvaged from the Boeing cockpit, splicing them into several large wire bundles connecting the various components. This allowed me to separate the glare wings from the MIP, and also to remove all of the MIP panels from the frame in groups of 3 or 4.
FDS uses a shelf that spans the full width of the MIP to support the monitors used for the displays. These are typical LCD computer monitors with their plastic cases removed. Fortunately this shelf was the exact width of the Boeing opening, so I simply needed to fabricate some brackets to hold the shelf onto the Boeing structure. I built an aluminum support for the Boeing landing gear lever to help support the FDS shelf.
After mounting the shelf, I attached the monitors and started a cycle of repeatedly dry fitting the now bare FDS MIP frame to figure out the right angle for the monitors and the proper place in space for the MIP.
