Panel Progress

The CAD file has finally been applied to metal. 6061-T6 Al .0625in thick.

The work was done at Watermark Engineering in Dublin; the owner is an avgeek who is plans-building a Fiesler Stork replica. Using their punch press we (the operator with looking on) punched out the panel and the shock-mount instrument sub-panel.

First up was the shock mount which has the multi-function display in the middle. I’m trying to keep the spirit of the original panel while adding the safety of engine monitoring and electronic AHRS. While I’m using it as an MFD, the unit (MGL iEFIS MX1) is actually a full EFIS with primary flight display, engine management and even an autopilot. The beauty of this unit is the level of configuration possible for the screens. I have designed several custom screens and started work on interactive checklists.

This is the stock Primary Flight Display Screen. It packs a lot onto a small screen and is not how I intend to use it. The checklists are able to show the relevant data directly on the list. The fuel level is manually entered at the start of the flight (as the tanks don’t have electronic sensors and I’m not opening the wings). The system then uses flow rate to calculate and display the remaining fuel in real-time.

The shock mount below is ready for paint.

From left to right will be: Airspeed, AHRS, Altimiter, EFIS, VSI, DI/AHRS (backup function), RPM (Tach). So if the 6-pack is supposed to be in front of the Pilot this is missing VSI, DI and Slip/Skid. However, the AHRS has the DI built in, so heading is shown on the DI. Thus all that’s missing is VSI and skip/skid.

The iEFIS let me build a screen that has all the engine management display, the VSI, slip-skid, AOA, and G-meter so rounding out and exceeding the 6-pack, while also allowing me to control the COM, NAV, and Transponder from the top bar of the screen.

All of that shock-mounts into the panel below which retains the piano keys and hides the fuse panel behind the glove-box door. The slot on the left is for my glasses and the (backup) paper chart I don’t tend to look at as I mount SkyDemon on an 8″ tablet on the yoke.

The punch press “nibbles” the shapes using various round and rectangular punch and die pairs. There was quite a bit of filing and sanding to do to finish it up. It certainly beat hand cutting it!

The result so far is shown below with the piano keys test fit.

If the panel looks too deep (tall), that’s because it is. There are two bends to be made along the bottom to reinforce by forming a u-channel along the whole bottom of the panel. The shock mounting points (tabs) need to be folded also. That’s beyond what I can do here, so it should be done some evening this week at Watermark.

From the back you can see the rebuilt piano key mount with new switches and the (seriously overbuilt) electrical system. Attached to the map box are a stratux (ADSB-in) and 5V power supply for 5 USB charging points to power cameras and tablets. Of course that’s about as tidy as it is ever going to look as the wiring will be a bit of a mess. Have to finish up the folding and painting before I get to that point.

3D CAD for your panel? – Recommended!

Learning a CAD package is non-trivial. I have spent many hours in Solidworks and on occasion thought to myself, “this is a waste of time, I should be working!” However, I have now found 4 separate errors in the panel that would have resulted in having to recut it. Given I have to get 6061-T6 from spruce in the USA, shipped by UPS, it comes out to about $150 per 2’x’4 sheet delivered. Then the cutting it out labour on top of that means remaking it would not be cheap!

Solidworks is very expensive – I just bought it for work and a single seat in the UK is GBP4K + support! Joining EAA gets you a student engineer license as part of your membership. I recommend it!

As I can’t get to the aircraft at the moment due to the Covid-19 lockdown, I decided to “waste” some time tracking down 3D models of instruments to stick into this model. It turned out not to be a waste of time at all. I had left plenty of space for each instrument based on the hole patterns until I tried “installing” them in Solidworks and they snagged on the shock mounts and the edge of the cut-out for the subassembly.

I didn’t have a model for the MGL Blaze unit I’m using as DI and AHRS so was going to assume it must be the same as the other instruments – they’re all standard, right? Wrong. I knocked up the Blaze part and installed it in the subassembly which required more tweaking to get everything clear of snags and obstructions.

In short – all the time spent in CAD has saved money, aggrevation and the delay that would have occurred if I had to buy more Al in from the US.

Still Here!

The work has continued and progress has been made. (We’ve had an election so the passive voice seems to be in fashion.) This is the results of moving the panel from 2D CAD (QCAD) into SolidWorks (thanks to the EAA for the low-cost licence).

Much more to come and as I’m in documentation mode, I’m planning to update this over the next few days!

DRAFT Panel Design

I’m attempting to strike a balance between keeping the quirky nature of a 170 panel and leveraging modern avionics – while NOT spending a fortune.

To that end, the venturis and gyros are gone and this is the draft of her new panel. I’m planning to print it at scae and stick it to the old panel and decide what I like/don’t.

Again the hours logged against this are a guesstimate over several days of on and off research and sketching.

The panel is bare

Everything is now out of the panel. Figured out how to get all the controls out of the panel and despite being aware of the ball bearing in the carb heat control, still managed to lose it. Oh well!

The suction system is removed and a secondary static line that wandered up the A-post and connected the altimeter only has been removed (and retained in case it turns out to be needed.)

I’m starting the CAD work for the new panel and the wiring diagram(s). Away all weekend and next week on familty vacation, bringing laptop to continue research and drawings.


Piano Keys

Everything to date has been tearing stuff out for inspection and replacement. All necessary and interesting but I hit a snag with the last few controls on the panel so I decided to work on some cosmetics.

The piano keys are a trademark feature of the 120/140/170 family. The 6 switches protrude through the panel and some designer went a bit art deco with them. I’m keeping them (of course) so they had to be smartened up. This restored Cessna 140 has them aong the bottom of this photo.

Removed last weekend, they looked like this (except where I had started cleaning:

The switches behind them were all different and mostly trashed. One died during extraction.

Now they look like this:

The brushed look is intentional (not original) there was too much pitting to just clean and polish them up. Several hours with grinder and polisher and they look and feel much nicer. Not sure why someone drilled holes in the centre piece; and couldn’t get them symmetrical.