Xref: utzoo rec.aviation:13309 sci.space.shuttle:2785
Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!haven!vrdxhq!bobs
From: bobs@vrdxhq.verdix.com (Bob Smart)
Newsgroups: rec.aviation,sci.space.shuttle
Subject: Re: SR71 to be retired October 1st, rumors regarding SR-71
Summary: JP-4, JP-5
Message-ID: <15751@vrdxhq.verdix.com>
Date: 31 Mar 89 22:57:37 GMT
References: <524@gonzo.UUCP> <1475@petsd.UUCP> <13987@elroy.Jpl.Nasa.Gov> <7855@venera.isi.edu>
Followup-To: rec.aviation
Organization: Verdix Corporation, Chantilly,  VA
Lines: 37

In article <7855@venera.isi.edu>, raveling@venera.isi.edu (Paul Raveling) writes:
> 
> 	The real danger isn't the liquid, but vapors.  Although
> 	most fuels are more benign, watch out for JP-5  -- it's
> 	volatile and the vapors are heavier than air; it'll
> 	lie on the ground and wait for your cigarette instead of
> 	dissipating quickly.
> 
> 	This problem is why only the military uses JP-5, and I'm
> 	not sure how much they still use it.  As for buckets of
> 	gasoline, that may be safe, but I'd prefer not to be close
> 	if you chuck a cigarette into a nearly-empty gas tank.

You are thinking of JP-4. The Air Force uses JP-4 which is very
vaporous. It ie what is called a wide cut distallate. The Navy
uses JP-5 which is a narrow cut distallate and therefor has a 
much lower vapor problem. That is specifically why they use it
They have an aversion to vapors building up on confined hanger
decks. I believe JP-5 is much closer to civilian Jet-A but
being an ex AF type I only dealt with it in annual safety
bbriefings and when one of our planes refueled at a Naval
Base that didn't have JP-4 (some have a limmited supply for
tenant units. The difference for us is the fuel gages read
differntly on the two (different specific gravity). The Navy
was real touchy though. If any JP-4 got into their fuel
system they had to completly purge the system. To complicate
the matter further NATO uses an even different fuel. They
refer to it as F-?? (I think JP-4 is F-41 and their standard
is F-40 but its been a long while) That we call JP-8 ( I always
got that one and SR-71 fuel mixed up is SR-71 fuel JP-7? or
am I reversed again(:-)) Oh well enough dissertation on jet
fuel last comment though- when unleaded mogas was 1.00 a 
gallon in tidewater Virginia our squadron payed 1.55 a gallon
for JP-4 to Base Fuels and we used ~3600 gal for each F-15
flight.

Bob Smart (bobs@verdix.com)