In article ,
Paul Hirose writes:
Jeremy Thomson wrote:

In my 'Great Planes' video of the Northrup F5 Freedom Fighter it
talked of the 'Scochi Tiger's being brought up to USAF standard with
among other things 'Jettisonable Pylons'.
I suppose if an aircraft had taken a hit in a fuel tank & you
absolutely must wring out every last bit of range to get you out of
indian country, jettisoning the pylons would save a little weight &
drag.

I don't know about the F-5A, but a full set of five F-5E pylons weighs
670 lbs according to the 1978 flight manual.

It's not weight so much, as the extra drag. A wing pylon typically
adds about 0.05 - 0.1 sq ft to the Equivalent Profile Area. On a
small bird like an F-5, that's an awful lot.

The book's cruise graph says a clean F-5E gets .260 nm per pound of
fuel. With five empty pylons, mileage drops to .205 nm/lb. (At best
cruise altitude and speed, carrying 1/2 max internal load)

Most of that difference will be due to drag, rather than weight.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster