Re: Geared turbofans

Date:         26 Apr 98 03:44:53 
From:         Damon Rinard <>
Organization: Damon Rinard --
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Low Rider wrote:
> Damon Rinard wrote in message ...
> >I understand P&W are using re-cambered PW4000 fan blades to help develop the
> >blades for the new engine.
> So far as I've hear, the GTF's Fan has not been finalized.

Yep. That's why I said "develop".

> As an aside, how would one recamber a
> shrouded blade?

Hot die. The recamber won't be perfect near the shrouds, of course, but
by exceeding the temperature and time allowed for regular repairs, they
can change the profile quite a bit along most of the length of the
blade. The new twist would throw the shroud face geometry out, so
they'll have to be welded and machined.

I imagine recambering existing blades might be cheaper than making new
blades, but I don't know if they would have to make new forgings or if
they could just machine a PW4000 forging to the new section profiles.

At any rate, perhaps the recamber is just a first guess, and later
protos might be new manufacture.

Damon Rinard