Tests by NASA with a modified fighter jet have shown that novel airframe shapes can reduce the boom.
Beyond that, the cost of the airframe could easily amount to the same again or more.
The engines had to be pulled from the airframe and examined for hairline cracks and microscopic wear.
And as Zafar Khan of Société Générale, a bank, notes, the CSeries is a new airframe and a new engine, a double risk.
If forced to keep the A-10, the air force calculates it would need to scrap 14 squadrons of multipurpose F-16 fighters to save the same money.Though tough pilots sit in armoured "tubs" of titanium, and the airframe can survive small-arms fire the A-10 is horribly vulnerable to surface-to-air missiles, so it is only good in very specific circumstances.
It hopes to have its supersonic business jets airborne by 2010 or 2011, by which time SCIA is unlikely even to have made a dent in the ICAO regulations.Aerion's approach is based on the massive improvements in engine and airframe design since Concorde, says Richard Tracy, the company's chief technology officer.
Airlines can then choose which airframe to buy, and which engines, and there is competition in both fields.
Dr Krapp's colleague Mirko Kovac is now attempting to do this.HovercraftOne way manoeuvrability might be engineered into a drone's airframe is shown by the work on hawk moths.
That translates into a double saving in fuel that has to be hauled along for the ride as well as in the airframe of the launch vehicle itself.
Apart from its ingenious wing design, the airframe was beefed up to meet wartime duties.
The stresses on the airframe, caused by the pressure difference as the plane climbs and descends, make the structure expand and contract whenever the aircraft takes to the air.
