From wood and fabric contraptions held together by cables, the art of flying has evolved to carbon composite and titanium alloy marvels controlled by complex avionics. A century of aviation has seen the invention of many different machines and crafts, most of which have become obsolete although they may still be found in museums around the world. The Sri Lanka Air Force Museum at the Ratmalana Air Force Base is a treasure trove of knowledge, offering unique insight into aviation in Sri Lanka.
Amongst her many historic exhibits stands the first flight simulation system brought to Sri Lanka decades ago.
When the First World War broke out, there was an urgent need for ground-based pilot training. Several attempts were made to build devices which could simulate instrument flying techniques. After the “Link Trainer” was invented in 1926 by Edwin Albert Link it became widely used by many of the Allied air forces during World War II and helped to train thousands of pilots and navigators.
The trainer was made of a system of pumps, valves and bellows which responded to the pilot’s controls. The inventor used his extensive knowledge in organ manufacturing to connect a motor to the trainer and mount it on a pedestal giving the pilot a range of motion. A student pilot could ‘pilot’ the trainer to pitch, dive, roll and climb. In training he relied on the instruments in the cockpit to ‘fly’ the device.
The instrument readings in the cockpit are reflected to an instructor outside who guides the student to navigate a given flight path. Another important feature was the fact that the actual flight path the student navigates was ‘drawn’ on a map by a mechanical apparatus.
In early 1963 the Royal Ceylon Air Force procured a variant of the Link Trainer (D4) from Air Trainers Ltd of United Kingdom. Air Trainers Ltd manufactured several versions of the Link Trainer under licence from Link Aviation Devices Inc. The trainer was used by the fledgling Air Force in training many of her early pilots and was only retired out of service in the late 1980s, after which it fell into disrepair.
In 1982 attempts were made to repair the trainer. A team of Air Force engineers and specialists from the University of Moratuwa were assigned the task but found it beyond economical repair.
As the operators who manned the trainer left the Air Force, operational knowledge of the device was lost. For the next 27 years the Link Trainer was buried in a maze of other antique machinery at the Aircraft Preservation and Storage Unit (APSU) which is found within the Ratmalana Air Base.
During an annual inspection of the APSU, the present Commander of the Air Force Air Chief Marshal Roshan Goonathilake after seeing the Link Trainer, recalled how it functioned during the 1970’s and the valuable service it rendered. He promptly directed Commanding Officer Wing Commander Malinda Perera of the Air Force Museum to restore it to operational condition.
In August 2009 the Air Force Museum commissioned a team, led by Flight Lieutenant T.N.P. De Silva and also comprising Flight Sergeant Senarathne and Corporal Hemantha, for the task. The first task was to find relevant information of the D4 model. Faced with a lack of manuals and technical details the team searched the web for instructions and diagrams on the Link Trainer.
Help came in the form of scanned pages of a Link Trainer manual from an aviation expert Ray Kidd at the Norfolk and Suffolk Aviation Museum, England. The team had already repaired the three phased motor and set about substituting local ‘Rexene’ fabric to remake the torn bellows.
After studying the manual, the electrical system was restored and the instruments were recalibrated. Within weeks the trainer was pitching and yawing on its pedestal. The second stage saw the original sensing mechanism, based on a “Teletorque” system, duplicated on the simulator. By the end of October work on the exterior had begun and a new coat of paint was used to bring back the trainer’s pride.
After the final touches were made the Link Trainer was ready for her grand re-entrance into the Air Force museum. A few weeks later, when President Mahinda Rajapaksa opened the refurbished Air Force Museum, the Link Trainer in the No.2 hanger caught his eye.
The leader of the restoration team and the Commanding Officer of the museum were on hand to brief the distinguished invitees on the trainer.
Today the Link Trainer D4, which is one of the few still operational in the world, stands as a testament to the skill and dedication of the men and women who serve in the Sri Lanka Air Force .
The museum is open to the public from 9 a.m. to 4 p.m. from Tuesday to Saturday. See also http//: museum.airforce.lk or on www.airforce.lk.