What is a Jet Blast Barrier or Deflector

January 9, 2020 | Aviation, Barriers
When a military or civilian jet is about to take off, its engines can produce winds of up to 120 mph from its exhausts – as much as a hurricane. What’s more, these winds can travel as much as 60 metres behind the plane. The danger to personnel and the possibility of damage to other planes seems obvious. And it’s not just wind – the jet blast also creates very high noise levels, while some aircraft, such as military jets, have excessive levels of heat from their afterburners. Jet blast deflectors have a huge role to play in managing these problems.

Jet Blast Barriers

There are circumstances where the problems caused by the jet blast have to be managed very carefully: when military aircraft are taking off from the confined space on the deck of an aircraft carrier, for example, or when a jet is in maintenance and the engines have to be tested at full thrust to ensure that they’re working properly (this takes place in what is called a “ground run-up” enclosure).

Barriers are required to provide protection from the wind, noise and heat that jets produce (this is collectively known as “jet wash”). But clearly, these have to be a special kind of barrier to deal with such extreme challenges. Not only that, but because space is often at a premium at airports, the barriers – also called “jet blast deflectors” – either need to be portable so that they can be moved or to be capable of being raised and lowered.

To be effective, jet blast barriers have to have a design that is aerodynamically efficient. The design needs to be regularly updated as new materials and technology become available. The barriers also have to be available in different sizes so that very large planes like the Airbus A380, or small ones like corporate jets, can be accommodated.

When Noise Is the Main Challenge

There’s a particular demand today for acoustic barriers. This is because population growth has led to more housing around the perimeters of airports, while growth in air travel has led to a greater volume of aircraft using the airport. This can add up to conflict unless the noise is managed and confined so that it is less of a nuisance to the surrounding community.

Communities affected by airport noise need to know that the airport and airlines are doing everything they can to minimise the problem. It used to be the case that concrete was used to provide barriers to contain excess noise. However, while concrete is good at limiting noise transmission, it’s heavy, hard to move and not very environmentally friendly.

New high-tech acoustic barriers use sound-absorbing materials that perform as well as concrete but result in a barrier that is much easier to move. While the “ground run-up” enclosures used in maintenance can be fixed structures, these jet blast deflectors, built from prefabricated components, can be disassembled and rebuilt very rapidly.

 
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