Threat Axis

Ok – I have kept everyone in suspense for long enough. Here is a side view of the same plane – and you can start answering some of the questions I posed.

This was a flight demonstrator for the Shaped Sonic Boom program. The thought was that a modified underside of the aircraft’s fuselage could potentially reduce the sonic boom that an aircraft made when going supersonic (Mach 1+) speeds.

[The newest jet engine's - i.e. the F119 on the F-22 Raptor - no longer has to go to afterburner to get to supersonic speeds. One of the reasons that the Concorde wasn't able to make money (and got retired) was because it was constantly on afterburner (and burned a huge amount of jet fuel). Beyond the fuel costs - the other reason that the Concorde wasn't successful - was because it was restricted to overwater flights. Because on an overwater flight - there was no homeowner's association or EPA to complain about the noise pollution].

Have you figured out why DARPA was pushing this research from the comments above?

Militarily – there is no point to have a Stealth (Invisible to radar) aircraft if it leaves a sonic boom footprint/trail along its flight path.

Commercially – think of the opportunity for an airline or express shipper (FedEx or UPS), if they could fly twice as fast for the same amount of fuel. Think of the surcharges!

The only thing standing in the way of either of these possibilities – now that the fuel economy has been improved – is the Sonic boom’s created. Now – we can’t rewrite the laws of aerodynamics as they apply to the Sonic boom. But this was an attempt to minimize the impact of the Sonic Boom so that restrictions on where Supersonic flight could take place – could be relaxed.