Re: Jettisonable Pylons?

[Jeroen Wenting]

Indeed they would be jettisoned only if doing so would be critical to either
the mission of the survival of the aircraft.
The situation you mention is one, another is where the pylon itself is
heavily damaged causing a lot of drag which would prevent the aircraft from
reaching home.

Or you might think of an F-22 carrying external fuel to penetrate into enemy
territory jettisoning those tank and pylons to decrease its radar cross
section for the commencement of the combat part of its mission (and meeting
a tanker on the way out).

"Jeremy Thomson" > wrote in message
m...
> 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 guess that meant the pylons with which the bombs, rockets & fuel
> tanks were attached.
> 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.
>
> Under what conditions would plyons be jettisoned?
> I dont know but is it usual these days for fighters to return to base
> keeping their empty drop tanks with them?
> Are plyons still jettisonable as USAF standard?
>
> Jeremy Thomson

[David Windhorst]

Jeroen Wenting wrote:

> Indeed they would be jettisoned only if doing so would be critical to either
> the mission of the survival of the aircraft.
> The situation you mention is one, another is where the pylon itself is
> heavily damaged causing a lot of drag which would prevent the aircraft from
> reaching home.
>
> Or you might think of an F-22 carrying external fuel to penetrate into enemy
> territory jettisoning those tank and pylons to decrease its radar cross
> section for the commencement of the combat part of its mission (and meeting
> a tanker on the way out).
>
> "Jeremy Thomson" > wrote in message
> m...
> > 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 guess that meant the pylons with which the bombs, rockets & fuel
> > tanks were attached.
> > 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.
> >
> > Under what conditions would plyons be jettisoned?
> > I dont know but is it usual these days for fighters to return to base
> > keeping their empty drop tanks with them?
> > Are plyons still jettisonable as USAF standard?
> >
> > Jeremy Thomson

I recall seeing an account somewhere -- might have been the A-4 Squadron Signal
volume -- of a Skyhawk pilot providing cover for a pilot rescue in Vietnam in
which he had expended all his ordnance, and as a desperation measure to keep
the bad guys' heads down, made a pass and released his multiple ejector racks.
For whatever it's worth, he said it worked.

[Paul Hirose]

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.

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)

Imagine your car dropping from 26 mpg to 20.5 mpg - quite a
difference. You might be tempted to throw that roof rack away. On the
other hand, if it's not your car and you will have to explain the
missing rack...

BTW, the company name is spelled "Northrop", and I've always seen the
nickname spelled "Skoshi Tiger".

--

Paul Hirose >

[Peter Stickney]

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