Tempête restoration: The Electric System (Part 1, Disassembly)

Since the Tempête has a single cantilever wing with a carry-through spar, it is much easier to work on the electric system with the wings still unmounted. The aircraft was purchased without avionics, so I will need to install at least a transponder and a new radio, which is much easier sitting or standing instead of lying upside down in the assembled aircraft.

The first thing to do was to get a grip of the already installed system by looking into the documentation.

Original wiring Diagram for the Tempête

While looking at the diagram, it became apparent, that this isn’t what Mr. Wirenfeldt had built in the end, or it has been altered quite a lot – which would be quite normal for owner built and maintained aircraft. The main difference was, that the Tempête wasn’t built with a starter, but has two instead of one fuel tank.

So I just omitted the old plan and started to investigate on the „living“ object.

The Panel already shows deviations to the wiring diagram.

As the panel was installed between two bulkheads, it wasn’t possible to uninstall it in one piece. At first I disconnected the lines that I was able to reach through the cutouts for the missing instruments. Then I tried to tilt the panel, so it would become free from the bulkheads. This did not work and I needed to separate the lower electric panel from the main instrument panel.

Electric Panel separated from the rest

With the electric panel separated, it became apparent, that I will need to redo all of the electric installation, not just add the radio and transponder. Despite the low time of the airframe – it has spent a mere 50 hrs in the air, I have found many problematic installation issues.

Plug for the turn and slip indicator

The turn and slip indicator was shortened in the coupling. Also, there was no strain relief, so it became disconnected shortly after disassembly.

A „nice“ short at the main power bus

There were several shorts between GND of some instruments and lighting wires and the main power bus. Often, shielded wires were used with the shield as gnd. On some of these, unknown isolator material was used that became brittle and started to crack open.

magneto switch

The magneto switch has been grounded while installed. The GND wire just separated from the switch during uninstall. I cannot imagine the aircraft being easy to start with this installation.

Gnd „terminal“ screw

Many of the main wires for Battery GND or the Main bus had no connector at all. Just a screw driven through the wire. I have found at least 4 ground terminals all over the panel, some in direct contact with power wires.

Mystery-Installation on the brakes

And some items are a mystery to me, like this item on the brake cylinder. I haven’t found out exactly what it’s supposed to do, but it might be a hydraulic switch of some kind.

When buying an amateur built aircraft, you need to take a very close look to all the details. Craftsmanship will vary not only between individual aircraft, but also within one aircraft. A builder might be virtuous with wood or metal and have no sense of electrical systems, and vice versa.

This is how the cockpit now looks like.

The next steps is to make a complete new electric layout for the Tempête. Thankfully, with just a few basics and without a starter, it is a very simple system to begin with.

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