A400M About To Fly

[Garry Russell]

http://news.bbc.co.uk/1/hi/business/8383212.stm

Garry

[TobyV]

About time too! I cant remember how long this project has been on the burner. I may be missing something, but in essence its a four turboprop transport and thus shouldn't be "that" hard to get right, should it?

[Garry Russell]

HI Toby

Din't know the full story but engine software problems has been an ongoing issue. ..maybe they were using Vista

Surely a Turbo prop is more comples and could suffer more delays than a jet as they have to develop the jet engine and the propeller??

Garry

[SkippyBing]

thus shouldn't be "that" hard to get right, should it?

If you just wanted to recreate the Hercules then no, however the A400 is much more powerful than the C-130, if you search for pictures of the Herc test bed it looks like it could fly just using the test engine and turn the other three off! They're pretty much at the cutting edge of what they're trying to do, hence the problems which hit all programs that are going beyond what's already been done.

There are various reasons for choosing a prop vs a jet, mostly to do with efficiency at cruise speed, using a jet may not have made development any simpler either, the C-17 had to accept a reduction in some of its performance targets because the engines weren't up to it. I think the main problem with the program is that it's a new airframe and new engine, which never seems to be a good idea...

[Garry Russell]

Wasn't the Herk testbed the former RAF Snoopy XV208??

Garry

[SkippyBing]

Think you're right Garry, obviously they couldn't find another use for a relatively low houred C-130K....

[TobyV]

Garry - not sure about propellers but I imagine they are no harder than a front fan. Front fans are actually pretty complex. The high aspect ratio nature of the blades, the fact the flow is transonic (and thus by definition supersonic in places) and the various rules on noise, bird impacts, containing single blade losses actually makes their design very complex.

[Garry Russell]

Props have complex pitch mechanisms and often power changes need different shaped props.

But this seems to be a software problem

Garry

[TSR2]

Skipp hit the nail on the head, the dealys are largely down to the new airframe AND engine / props. Most other aircraft will use existing powerplants and this makes the development cycle notably shorter.

[TobyV]

This is true, Brian Trubshaw noted in his autobiography that new airframe/proven engine or proven airframe/new engine was always preferable than both at once. Notable cases of the latter included the TSR.2, Vanguard and I think the Britannia?