Menu Sign In Contact FAQ
Banner
Welcome to our forums

Random avionics internals

WOW – that one uses valves!

An amazingly small number of them, too.

Administrator
Shoreham EGKA, United Kingdom

Perhaps I should add this to the collection of avionic photos

Your number 5, solves 8.33khz spacing or any subsequent upgrades: you can tune continuous Frequencies (like old AM/FM bands radios )

Paris/Essex, France/UK, United Kingdom

A_and_C wrote:

Perhaps I should add this to the collection of avionic photos

Works as either a COM or a NAV. Love it!

ESKC (Uppsala/Sundbro), Sweden

Ibra wrote:

Your number 5, solves 8.33khz spacing or any subsequent upgrades: you can tune continuous Frequencies (like old AM/FM bands radios )

…or like modern HF radios.

EKRK, Denmark

I should mention that both those radios are exhibited at the aviation museum at Stockholm Arlanda Airport.

It’s quite as small museum but packed to the gunnels with interesting exhibits, the museum is easily accessed from the terminal by taking the free airport bus to the Radison Blue hotel then a short walk.

With an entry fee of €5 it represents superb value for money, check the museum website for the opening hours.

Someone kindly sent me some Badin-Crouzet autopilot parts.

It was built in 1972 and is amazing stuff in the sense of having been developed apparently in a way which excluded knowledge of the world outside the designer’s workshop to the maximum extent possible Well, unless it was developed in say 1960. Does anyone know the history of the Robin company and Badin autopilot usage?

First we have what looks like a servo controller – for a pneumatic servo. This box contains an ingenious two-way airflow controller which can drive an actuator left or right

The valve is driven by a leadscrew which is driven by a DC brush motor. No expense spared here – look at the flexible coupling on the motor. The valve is beautifully brazed and would have been a bastard to make, and expensive. The electronics are way over the top. The MJ22xx transistors are 1960s but were apparently still made by SEMELAB in the UK in 2002 which suggests a demand from old military users.

The use of open trimpots

is a guarantee that the thing will out of “alignment” pretty fast. These have practically zero immunity to moisture. So clearly the designer was clueless, knowing the application.



The whole thing is handmade

Even the case screws are handmade; machined screws

This is some sort of a turn coordinator gyro which I could not get apart easily but it seems to output an air stream

Interesting details include a method of locking the shaft of a potentiometer using an elaborately machined mechanism

That is way silly since these locking devices have been around since for ever

but maybe they were not known in France?

However, some of it is of a much lower build quality e.g. this unknown box




The metal case devices are 741 op-amps which came out late 1960s I think.

Finally we have another unknown box which is again hand-made to a good standard

and with really complicated mechanics

Look at the components strung across the standoff pillars, to avoid using a PCB

I reckon it might be a design from the 1950s or even before, which was slightly modernised with newer electronics c. 1970.

Administrator
Shoreham EGKA, United Kingdom

Just stopping by to say I like reading about this old stuff.

always learning
LO__, Austria

Me too. Thank you for your efforts in taking the time to post the pictures and comments.

Sans aircraft at the moment :-(, United Kingdom

Peter wrote:

Look at the components strung across the standoff pillars, to avoid using a PCB

It’s called cordwood construction and was I believe quite popular in aerospace in those days. The Apollo Guidance Computer widely employed cordwood construction.

Andreas IOM
Sign in to add your message

Back to Top