60 years of the Bristol 171 Sycamore

She is as unique as she is fascinating! The Flying Bulls’ own Bristol 171 Sycamore is celebrating her 60th birthday. Not only are her rotor blades made of Maplewood an absolutely unique feature, the Sycamore in Hangar 8 is also the only flight-ready model of her kind worldwide. Not to mention her exceptional flight characteristics. But first things first…

Manufactured in Weston-super-Mare, England, for the German Army in 1957, the aircraft with the identification number 13475, which is now owned by The Flying Bulls, is one of two models with what was, back then, considered to be VIP paintwork. All other 50 Sycamores manufactured for the German Army bore the usual olive military colour scheme. After ending her military career in 1969, she changed hands twice in Germany before ending up in Switzerland in the fold of Peter Schmid, a winemaker who is also a veritable aviation enthusiast. During that time, the helicopter received a new, completely unique look. With the official approval of the Queen of England, the machine was repainted to resemble the last Sycamore ever to be flown in England - in honour of the Royal Air Force. She still dons the same striking paintwork today.

But how does such an aircraft end up in the custody of The Flying Bulls? At this point, a certain Dieter Hasebrink comes into play. The former German Army technician is a true Sycamore expert and knows every tiny detail about the machine. Ever since the “Bundeswehr” started replacing the Bristol 171 helicopters in 1968/69 and selling them to civilians, every single model has, by his own admission, passed through Hasebrink’s hands. Accordingly, he was indispensable as a maintenance specialist during the time that the Sycamore donned its leaf-frog green paintwork. However, Peter Schmid lost interest in the helicopter after a while. When Hasebrink came across a newspaper article about head pilot Siegfried “Blacky” Schwarz he thought: “He’s the man!” In 2007, he wrote him a letter that resulted in a phone call a few months later. “Hello, this is Siegfried Schwarz. I’m calling about the Sycamore.” Three years later, the Bristol 171 was relocated to The Flying Bulls in Salzburg. Seeing that there were no more pilots capable of flying the Grande Dame, she had to be moved by road.

What makes the Sycamore so special? Basically everything about her is unique. In the absence of licensed pilots and technicians, Blacky Schwarz and Dieter Hasebrink jointly devised a test flight programme to obtain a flight license via Austro Control. The approval process was immensely complex in that the Bristol 171 Sycamore was the first of its kind to be awarded Austrian approval.

The practical documentation, which was carried out at the same time as its theoretical counterpart, was extremely challenging, even for renowned experts such as Dieter Hasebrink and his team. Whether it was overhauling the engine or adjusting the valves, every aspect proved to be highly complex. As one of the main technical characteristics, he highlights the fact that the Old Lady has special rotor settings, whose static balancing requires extensive know-how and sensitivity. By means of a scale, the technicians determine the heaviest rotor blade, which serves as a so-called “base blade”. In the process, they ensure that all blades are equally heavy by applying weights to their brackets. This sophisticated procedure “is essential when flying this helicopter”, says Hasebrink. “Especially as the entire steering system of the Sycamore is mechanical.”

To make matters worse, Siegfried Schwarz had to learn how to fly the Bristol 171 Sycamore from scratch all by himself. After all, there was not a single person worldwide with a valid license. To this end, he needed to “fly off” a vast amount of requirements. In addition to five hours of hovering, the head pilot of The Flying Bulls needed to complete flights at countless different heights and speeds, as well as having to undergo an emergency programme (auto-rotation in the event of an engine failure). Dieter Hasebrink was always by his side during the process. With bated breath, Hasebrink remembers Siegfried Schwarz’s first flight in the Sycamore. Her unmistakable features include the enormous main rotor with a gigantic diameter of 14.80 metres, as well as her liquid trimming that moves 27 kilograms of water in a longitudinal direction via a pump and duct system. “It requires immense finesse!” During his very first start, Siegfried Schwarz executed a steep launch. He was so close to the ground that the Sycamore’s spur touched down at the rear. However, Schwarz “managed to turn the machine back into the wind. I have the utmost respect for how swiftly he regained calm control. That was an incredibly impressive achievement”, Hasebrink still marvels years later.

All these efforts, the thousands of hours of maintenance, the unfailing perseverance of Hasebrink and his team, and the courage and stamina of Blacky Schwarz paid off in the end. On the 1st of February 2016, the Sycamore obtained the type approval of Austro Control and has been in operation under the auspices of The Flying Bulls ever since with the registration OE-XSY. How does this make technician Dieter Hasebrink feel? “It feels like the ultimate fulfilment. It’s the perfect ending for my personal Sycamore story.” And how do Siegfried Schwarz and The Flying Bulls feel? For them, the search for yet another unique aircraft has reached its peak. They are the ones who made the Bristol 171 Sycamore, with all its unprecedented properties, what she is today: the world’s only airborne model of its kind.

Happy birthday, Sycamore!