Boeing reveals successor to legendary Blackbird SR-71 spy plane

Boeing has finally revealed a successor to the legendary Blackbird SR-71 spy plane, that can travel  at five times the speed of sound.

The new 'Son of Blackbird' was unveiled at an event in Orlando, Florida, but as of now it is only a concept design.

The new aircraft will take on rival Lockheed Martin's upcoming SR-72.

The rival firms are in a race to create a hypersonic aircraft capable of stealthy recon assignments as also strike missions.

Speaking to Aviation Week Aerospace Daily, Boeing's hypersonics chief described Boeing's plan comprising a two-step development process for the new war plane.

In the first stage flight tests will be conducted on an "F16-sized, single-engine" precursor vehicle that will act as a "proof of concept".

The second-stage envisages the creation of a "twin-engine, full-scale operational vehicle" with roughly similar dimensions to the 107-foot-long SR-71.

The company aims to develop an aircraft that can travel at speeds beyond Mach 5, five times the speed of sound.

Mach 1 or the speed of sound is around 1235km/h and Mach 5 would mean the Son of Blackbird would travel at 6,174km/h.

Typically a Boeing 747 passenger jet typically hits cruising speeds of only 885km/h.

"It's a really hard problem to develop an aircraft that takes off and accelerates through Mach 1 all the way to Mach 5 and beyond," Kevin Bowcutt, Boeing chief scientist for hypersonics told Aviation Week.

"The specific impulse of an air breathing engine goes down with increasing velocity, so you have to make the engine bigger to get to Mach 5," said Bowcutt.

"But doing that means a bigger inlet and a bigger nozzle, and trying to get that through Mach 1 is harder," he said.

According to experts, hypersonic technologies including a combined cycle propulsion system that combines a rocket engine and a supersonic jet engine, are now sufficiently advanced to allow the planned SR-72 project to begin.