Those from the UK may be familiar with the Royal Air Force’s Tornado fighter jet, which was designed to fight in a theoretical nuclear war and served the country for over 40 years. This flying death trap (words of a serving RAF fighter pilot whom this scribe met a few years ago) was an extremely complex machine, with advanced technology for its time, but apparently had a bit of a habit of bursting occasionally ignites when in the air!
Anyway, the last fleet is now long retired and some of the tech inside is starting to leak into the public domain, as some parts can be purchased on eBay from all places. [Mike] of mikeselectricstuff dug inside the Tornado’s laser head unit, which was part of the bomber’s laser-guided missile subsystem, and what a journey of mechanics and electronics it is!
This unit is largely dumb, with all the clever stuff going on deep in an avionics bay, but there’s still plenty of older high-end tech on display. Using a xenon discharge tube pumped yttrium aluminum garnet (YAG) laser, operating in pulsed mode, the unit’s job is to illuminate the ground target with an IR dot , at which later fired missiles will point.
Designed for ground tracking, while the aircraft is operating at high speed, the laser head has three degrees of momentum, which is likely synchronized with the movement of the aircraft to keep the beam stable. The optical housing is quite interesting, with the xenon tube and YAG rod swimming in a liquid cooling bath, inside a metal casing. The beam bounces around inside the housing using numerous prisms and is triggered by a Q switch which allows the beam to build up in intensity before being released onto the target. Also worth noting is the largest photodiode we’ve ever seen – easily over an inch in diameter, split into four quadrants, allowing the sensor to resolve directional changes in the reflected IR spot and track its error. A separate photodiode receiver is part of the time-of-flight optical rangefinder, which is also important information to have when targeting.
There are plenty of unusual three-phase positioning motors, position sensors and gyroscopes in the mix, all beautifully designed and wired to military spec. It’s definitely a revelation of what was truly possible during the Cold War years, even if such technology never quite filtered down to civilian applications.
We’ve seen a few things on the Tornado before, like that over-engineered attitude indicator, and here’s the inside of an old QAR (Quick Access Recorder) airplane.
Thank you [Zane] for the tip!