Busak+Shamban were able to employ all their experience ofsealing in high-pressure systems to offer Airbus robust solutionsfor the A380?s hydraulic pressure of 5,000 PSI, 66% above the 3,000PSI norm for commercial aircraft.
Advanced design of the new Airbus A380, with its carryingoptions of 555 or 850 passengers, has led to operating costs some16 percent lower than other wide-bodied aircraft. A major factor inrealising their ambitious performance targets is Airbus Industries(Europe) identification of system suppliers who could employ newtechnology to enable them to meet their objectives.
Busak+Shamban achieved this when presenting options for sealingin airfoil surfaces areas, where their unique silicone profileseals play a part in airflow optimisation of the flaps andfairings. These seals offer improved aerodynamics and thus, noisereduction and decreased fuel consumption.
Despite the designers of the new Super-Airbus A380 attachinggreat importance to weight reduction, the aircraft is the heaviestof its type with full fuel tanks its take-off weight can be over500 tonnes. To lift this load but to avoid increasing weight andsize of the hydraulic actuators, Airbus increased the hydraulicpressure from 3,000 PSI, the norm for commercial aircraft, to 5,000PSI. The greater pressure enables relatively small hydrauliccylinders to generate the larger forces required to retract andextend the undercarriage, as well as to adjust the rudders andflaps.
To offer solutions in this area, Busak+Shamban utilised theirwide experience of high-pressure systems, gained from their work onmodern direct injection diesel systems; known as 'Common Rail' and?High-Pressure Unit Injector?. These operate at system pressuresup to 29,000 PSI, making the hydraulic pressure of Airbus at 5,000PSI, appear relatively low. However, this still presented atechnological challenge to Busak+Shamban engineers, not only inmeeting pressure parameters but also in providing a solution thatmet stringent requirements for sealing security, maintainedlong-term strength, operated in temperature extremes and providedresistance to a wide range of aggressive media.
Though two propulsion units, with a total thrust of 227 kN, weresufficient for the Airbus A320; four propulsion units are needed togenerate the 1244 kN thrust required to lift the 550-seater A380.Newly developed Rolls Royce Trent 900 jet engines were chosen forthe task. The seals for the turbine blades presented specificchallenges with their requirements to operate over a wide range ofextreme temperatures and the necessity to seal lubricant into theengine, while excluding external media. Busak+Shamban innovativedesign for this application used composite construction materials,the fibre-reinforced sealing systems effectively providing optimumsealing in their harsh operational environment.
Busak+Shamban also supplies seals for numerous other aircraftprogrammes including Eurofighter EF2000, new NH 90 helicopter,Tiger, Airbus, Bombardier and Embraer. In addition to the RollsRoyce Trent 900 engines, Busak+Shamban sealing systems are usedwithin the Trent 500, V2500, BR710 and BR715 engine families.