A little update

As I concentrate on programming and hardware work you are not getting too much news here from the project. You can always visit and see yourself.

What has happened:

  • Completely moved all hardware from my attic to the real cockpit shell
  • Wired 3 headsets and got them working with online flying on VATSIM
  • MIP almost complete (missing second FMC and Lower Display Unit
  • All Glass Displays working through XPOpenGC and Rasperry PI’s
  • Temporarily installed two small displays for visuals (I would say the Sim is currently well fitted for IFR)
  • Heating and Cooling working but not yet connected to the Sim
  • Done a few test flights and continuing to improve systems for 100% reality.

What will follow next:

  • Development of three projector set up
  • Development of a wooden house around the cockpit to hold the curved screen and the projectors
  • Re-Engineering of Center Pedestal (rip off OpenCockpits and install SISMO hardware)
  • Acquiring a few reserve Rasperry PI 4B and 3B computers (they are not available right now)
  • Starting to build the Aft Overhead Panel
  • Re-Engineering of the Fwd Overhead Panel (rip off OpenCockpits and install SISMo hardware)
  • Complete installation of Audio / Intercom system controlled by Center Pedestal ACP and Aft Overhead ACP
  • Testing and introducing Teensy hardware in order to later replace SISMO hardware

A few current images follow here … feel free to ask about any specific technical details.

How to move Heavy Stuff without Wheels

I wanted to rotate the cockpit shell horizontally by 90 degrees (you may have read the article where we already had rotated it by 90 degrees vertically). The thing weighs around 600 kg and wheels are not an option when rotating in a circle.

The idea was: build skis of wooden plates and use frying butter to lubricate and get around static friction of the wood plates. I had no idea if it would work. This was simply a cheap try. The expensive solution would have been to rent a crane (been there done that, see here).

Fortunately it worked out thanks to the help of my neighbors (no names here in this public blog, but many many thanks again for their force and help!). Using frying butter it rotated with medium force needed … like on butter!

Take 1 (Turning)

Take 2 (Moving)

And … in order to build a house around the cockpit to fit the projectors and screens in a waterproof environment, the whole cockpit was moved away from the platform today … many thanks to the whole family for helping!

Fitting Custom Screens to the MIP

The journey has just begun, or as we say in german: Der Weg ist das Ziel. After adapting the nicely made upper part of the Boeing 737-800 MIP from SISMO Soluciones to the original Boeing 737-300 MIP stand below (see this post), the next task was to outfit the whole thing with proper electronics.

I have started with the MIP LCD displays and the FMC’s. Most cockpit builders use regular monitors and connect them to multiple regular PC’s. There are two uncessary parts in such a setup:

  • Monitor Case: There is no need for it as the monitors sit behind the MIP case anyway. The original monitor case further creates an artificial distance between the MIP glass and the monitor itself. It would be good to have the displayed content as close to the front of the MIP itself to avoid shading effects when viewed from the side.
  • One PC per Flight Display: There is no need for so many PC’s since the flight displays require a minimum amount of CPU/GPU power. They do not display 3D content. They however need to react in real time to the simulated contect. A delay of 100 milliseconds between aircraft movement and the reaction of the artificial horizon would be very hard to fly. So a 25-50 frames-per-second update frequency of the primary flight display and a maximum of 10-20 millisecond delay would be a good target.

The solution was to buy monitor screens and HDMI driver boards instead of the full monitor. With the variety of sellers on Ali Express this becomes rather simple. I’ve chosen the following models:

  • Captain and First Officer CDU: 1920×1080 18.5″ G185HAN01 and the HDMI driver board M.NT68676
  • EICAS CDU: 1680×1050 15.4″ LP154WE3-TLB2 and the HDMI driver board M.NT68676 (please select correct display model for its firmware and cables to match)
  • FMC CDU: 640×480 5″ LCD module including driver board (seems to be out of stock, you may ask the seller why)

For each of those displays I’ve selected a Rasperry PI (3B for FMC or 4B for the CDU’s) which runs XPOpenGC. First tests showed a very good performance within above specs. Rasperry PI’s use little power, are cheap, can be administered remotely and can be easily stowed in the center part of the MIP base.

You may find the following images helpful in case you build your own cockpit:

The Captain Side CDU: the monitor nicely fits close to the MIP case. You can also see the HDMI driver board and the monitor control buttons, which I have put to the back of the MIP, just in case I need them during operation.
First Officer side CDU. Same Procedure.
EICAS CDU was a bit more difficult. Due to the size and lightness of the monitor, it is a laptop screen, It needs to be handled with care. I also glued the top and left hand side in order to avoid stray light entry, especially from the gear annunciator and the EDC above. You also see the ISFD wires which had to fit the monitor mount.
The quality of the Full HD MIP displays is quite astonishing. You also see a fully functional WXR display.
Here you see all three monitors and one FMC in operation. The second FMC will be built once the MIP has proven to be free of bugs.
The three Rasperry PI 4B minicomputers in the center lower CDU bay. The lower CDU will possibly never be built since the B737-300 does not have space for it.

Making of the Integrated Standby Flight Display

The Integrated Standby Flight Display (ISFD) is used in all newer Boeing 737 jets. This instrument is thought to be a backup when all other (now digital) flight instruments fail. In the real aircraft it is a fully independent (in terms of power and sensors) and rather small replacement of the Primary Flight Display (PFD) with reduced amount of information. It will tell you altitude, attitude, bank, speed and heading. What do you need more? In the simulator, we can mimik its usefulness by e.g. turning off the PFD and keeping the ISFD on, simulating broken avionics. The ISFD has five buttons and a rotary encoder to set e.g. the barometric height, since its pressure is measured separately for the ISFD.

Original Image of the ISFD from http://www.b737.org.uk/flightinsts.htm#Standby%20Flight%20Instruments

SISMO Soluciones sells a very authentic “dummy” bezel of the ISFD for a good deal. However, as the description says, the buttons are just decorative. I have removed the button caps and have mounted real buttons behind those caps and a rotary encoder into the dummy bezel. Apart from destroying a few edges of the nicely painted ISFD bezel, the thing looks pretty nice and also works. The key is to use as little space behind the bezel for wiring and screws, since the EICAS monitor will have to fit closely to the plexiglas of the ISFD bezel. Oh, one note: the original plexiglas of SISMO Soluciones is a smoke glas, which looks nicely, but unfortunately “eats” too much of the monitor brightness. The solution was to simply cut my own transparent plexiglas. For those of you who would like to repeat my work, please be aware to buy an additional inputs daugther card and connect it to the SISMO Soluciones master card via the 10 pin downstream link since the ISFD needs a total of 8 inputs (5 buttons, 2 for the encoder and if you want, one for the encoder button).

In case you look for a low height rotary encoder that would fit your ISFD. I can recommend the ALPS EC11E18244A5, as for instance sold by Farnell.

Now have a look at the process and the result and compare to the original above …

Smartphone Battery now lasts 6 days

I have wiped the Fairphone OS (a standard Android) of my 4 year old Fairphone 2 and replaced it with the Lineage OS 18 without any google play and google play services. The problem with this solution is that you have to search your apps by hand and many of the apps still depend on google play services even if you find their binary (APK) to sideload. It is a pity that our world is so much linked to the privacy-neglecting services of Google and Apple these days.

The upside of choosing an open source variant of Android like Lineage OS. totally ignoring Google: my battery life went up from 3-4 days to 5-6 days again, like in the old times.

What does this mean to me: the constant data exchange of my old Fairphone through Google Play and Apps that sent usage data to Google permanently sucked 10-30% of my smart phone battery! I cannot explain it otherwise.

Air Travel: How it could be …

To be honest, I have a larger personal conflict between my professional engagement as climate change scientist, my private engagement on low fossil fuel usage on one side and my unbroken enthusiasm for aviation on the other side. I try to solve it by not owning a car, using things for a long time, repairing things five times and doing rather local vacation with my family.

From time to time, however, it would be cool to fly … not just in the home built simulator. Apart from the uncool carbon emissions, air travel has become non-enjoyable for most, especially with larger airports, security measures, waiting times and with a decreased uniqueness of the event of flying. Unless you upgrade for many bucks, but the increase in service still puts you and 360 others in a big metal canister after all the waiting time in the big airport. And I have never tried (and not even thought about trying) low cost airlines. The whole Corona thing has made me think about quality versus quantity when it comes to air travel.

So I thought about a possible solution and tried it out with my family. Lets revert back from mass transport with mass carbon emissions to personalized air travel and an adequate price tag. Price usually regulates demand and scale very well. A fair price includes service, uniqueness, fair salaries to pilots and maintenance staff and short boarding times. With a fair price for air travel the cost of offsetting carbon emissions is not of relevance any more (so carbon offset tax could even be much higher than it is). Which of course means that for a family of 5 like we are, such a personalized adventure will financially only be doable every 5-10 years … and possibly a long haul flight with such a service will not feasible for us at all. Which is good!

The opportunity was given by the charter flights offered this year by Belpmoos Reisen AG between Bern and Elba by contracting with Swiss Flight Services and using their King Air 350i aircraft with 8 passenger seats. They however did not offer flights at the date when we wanted to book the service. Thankfully they extended their schedule and we reserved 5 seats for the flight from Elba to Bern. They eventually found 3 more people to fill the aircraft. We went to Elba the classical way by train and ferry (well, the really classical way is by car, which is what 99.95% of all tourists do) and had a wonderful post-Corona holiday on the beach village Lacona.

And the adventure to go back from the small airport of Marina di Campo to Bern was really a great one with beautiful weather and very friendly staff of Swiss Flight Services. I wouldn’t want to miss it. It passed rather quickly but it was the opposite of the typical sardine box feeling of modern air travel.

Fitting the MIP to the real Cockpit

I have bought the high quality MIP with glareshield from SISMO Soluciones and wanted to put it on top of the original B737-300 MIP stand and then mount both things into the real B737-300 cockpit shell. Nice idea.

Of course the MIP stand totally changed from the -300 to the -800 (the FMC&lowerCDU bay is much wider now). And the really neatly build MIP from SISMO Solutiones would never fit into the really tight space of a real cockpit.

Also, and challenging everyone who argues that Boeing never changes a running system, the gear lever mechanics shifted by around 4 cm to the left in NG models.

By help of the circular disc saw and many hours of work later I can say that all those things are finally compatible and fit together. I also make sure that I can remove the MIP independently from the stand and independently from the glareshield/mcp in order to service parts once it is mounted.

See the photo story below …

Flight Management Computer using Rasperry Pi

Thanks to my colleague Piki from northern Germany and thanks to Dotsha747’s open source FMC PCB and hardware guidance I have been able to complete the first Flight Management Computer (FMC).

It uses a Rasperry Pi 3B instead of the Rasperry Pi Zero recommended by Dotsha747 since I want to use a wired LAN connection throughout the cockpit instead of WLAN. The Rasperry Pi 3B has more computing power and is further able to operate X11 and my custom OpenGC version very elegantly. The lightplates and keycaps are from OpenCockpits. They fit almost perfectly to the PCB of Dotsha747. The only problem was the EXEC light which I had to drill manually into the lightplate.

The 5″ screen comes with a VGA display driver is connected via a VGA-to-HDMI adapter to the Rasperry Pi and the keys are backlighted. The unit now only needs a 12V power supply (and if chosen) a LAN network cable. No more wiring puzzle in the cockpit, which will be especially helpful in the hardly accessible MIP.

One change was done compared to the Dotsha747 hardware: the encoder to tune the display brightness was connected to the display driver board as follows: Encoder Button is connected directly to display driver button “Menu”. Encoder signals are sent to Rasperry Pi and transformed to Up&Down pulses driving the display driver buttons “Up” and “Down” via the transistors Q2 and Q3 (DSPY and FAIL LED’s which are not supported by ZIBO anyway. Please watch out for R24 and R25 which I had to switch on my PCB Version 3.3.


This is straight forward with the rasperry pi zero which can be directly plugged into the connector of the FMC PCB without a cable. But you have to turn around the whole pin assignment by use of a female to female 40 pin connector if you mount the rasperry pi 3b over a flat wire cable. (I have burned a rasperry pi by this mistake, please be careful).

Our open source software package xpcockpit was extended by a Rasperry Pi module called xppi (Many thanks Piki for your edits!) and we also have adapted the OpenGC module Boeing737FMC for more performance and with an option to simply display the FMC screen without the keys.

J-Rails Mounted

Thanks to Pedro von SimuJabs who was able to exactly replicate the Boeing 737-300 J-Rails I could now mount the original cockpit seats. Original J-Rails are very hard to get and the often replicated Boeing 737NG J-Rails are not compatible to the Boeing 737 Classic mounting holes.

At the end, I had to still move the mounting holes by 0.5-1 mm, but the seats now move freely. Like with many completed steps in the cockpit building project it is now time to remove seats again to get space in the cockpit and store them until their final mount.

Where actually is the Minibar in a Boeing 737 Cockpit?

Nowhere. But I figured out that it is definitively a missing feature in a grounded Boeing 737 Cockpit. There is a perfect spot just above the foldable jump seat. And it can fit the adequate amount of glasses serving the maximum number of crew members (4) and a suitable amount of Grappa bottles for a 4-5 hour flight. Please respect the two fuel suppliers Villa de Varda (Italy, Trentino) and Gregor Kuonen (Switzerland, Valais) …