|
The CSIR measures the aerodynamics of model helicopters in the wind tunnel and test them as if they were airborne in the presence of wakes. Simulation may be used to complement flight testing as sea trials are costly, time consuming and potentially dangerous.
|
|
|
|
CSIR engineers in the aeronautics domain are investigating the effects of the wake behind a ship on helicopter landings. This stems from general research into helicopter wake effects that assessed the aerodynamic influence on a helicopter encountering the wake from an upwind helicopter. Wake effects can result in fatalities if not properly understood and accounted for.
Helicopters are routinely operated off ships and oil rigs. Wake encounters in the landing phase lead to greater risk, due to the lack of time for the pilot to react before impact. Extreme cases may result in the helicopter crashing overboard (in the water) instead of on the ship. The Australian Defence Force recently lost a helicopter in such a way that resulted in fatalities.
CSIR expert Peter Skinner explains that anything flying and/or moving in front of you has a wake that influences the handling of the aircraft you are in. "The wake has an effect," he says, adding that aircraft have been designed to fly in clean air and that wakes disturb their aerodynamics. "If an aircraft encounters a wake vortex near the ground, it may spell disaster." This risk impacts airport operations where minimum aircraft separation distances or times are specified for safety reasons.
He continues: "The flow distortion and turbulence of the wake phenomenon changes everything. We measure the aerodynamics of model helicopters in the wind tunnel and test them as if they were airborne in the presence of wakes."
According to Skinner, much research on this has been done internationally to "reduce the risk of helicopters crash-landing on moving ships". The CSIR's research into helicopter wakes, which started in 2003, was presented at the European Rotorcraft Forum in 2005.
Now, Skinner and his group are researching the changes produced by a moving ship on the helicopter's aerodynamics. "This is where simulation may be used to complement flight testing," he says, adding that sea trials are extremely costly, time consuming, and can compromise the lives of the crew. "In this way, we can identify the more challenging test points and prepare test pilots for what to expect."
This, he says, has to be done each time the navy acquires new types of helicopters and ships. "Typically, each helicopter type has to be cleared for operations onboard a frigate."
Skinner says that the experimental techniques were largely established doing the helicopter-on-helicopter research. "Through a relatively simple extension of this test technique we were able to perform research in another area," he says.
"Our results from helicopter formation flying have quantified potential power savings (i.e. fuel savings) that may be made by adopting a particular formation," says Skinner, referring to wind tunnel test results.
Enquiries: CSIR Communication
|
