Re: Propfans

Date:         05 Dec 96 02:27:18 
From:         falke@pweh.com ( 0 Falke_Charlie phone dist )
References:   1
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> In article <airliners.1996.2634@ohare.Chicago.COM>, "R. Adam Fogo"
> <bd362@FreeNet.Carleton.CA> writes
> >Is propfan or UDF research continuing?
> >I can't seem to find any current information.
>
> I think its all gone quiet, back to the labs, on the back burner ect.
> I think the vibrations gave them a bad time,also there was the passenger
> thing about propellers to contend with.
> Also conventional fans are getting better all the time

   It isn't on the back burner, it's in the attic.  Vibration was a
problem.  There was a rumor the Douglas demo airplane had sheets of
lead glued to the baggage overheads in the aft cabin to keep them from
rattling against the latches.  The passenger acceptance of propellers
is poor, witness the trend towards regional jets with only 70 or even
only 50 seats.  The other thing that happened is that fuel stayed
cheap.  We're still working on ADPs, which are ultra high bypass
geared ducted fans, offering much of the fuel savings of Propfans and
actual noise reduction of approx. 24db at the same power settings,
compared to turbofans, but airline acceptance of the reduction gear
system is a problem.

--
Charlie Falke                Pratt & Whitney Aircraft
System Test Team Leader      400 Main St. M.S. 121-05
203-565-9063 x1261 fax       East Hartford, Ct 06108