Re: Do airliner engens run at approximately constant speed, varying only torque?

From: (R. & L. Chilukuri)
Organization: Univ of California at San Diego
Date:         17 Jul 95 04:29:34 
References:   1 2 3
Followups:    1 2
Next article
View raw article
  or MIME structure

In article <airliners.1995.1061@ohare.Chicago.COM>,

>   As far as I know, high bypass turbofans measure their thrust output
>through the N1 (rpm of the fan) gauge, as opposed to EPR (engine pressure
>ratio, which compares the static pressure of the tailpipe to static
>pressure of the inlet, which I suppose could be considered ambient),

We had a discussion on this topic earlier: EPR is the ratio of total
pressures, not static pressures.

>   The 707-321 I used to work on did have spring-loaded blow-in doors on
>the inlets, or as I've heard some people call them, "auxillary air doors."
>They would really start flapping if there was a mild oscillating
>compressor stall... You could see them bouncing as you heard a "whoomp
>whoomp whoomp whoomp..." :-)

I have an old technical paper on the design of 707 inlets with blow in
doors. I hadn't realized that these devices made it into production!!