steve%revolver@gatech.edu (Steve Fischer) (06/14/89)
From: steve%revolver@gatech.edu (Steve Fischer) Perhaps this is a naive question, but I was reading an article on another board in which the author claimed that the sonic boom of an SR-71 (at cruising alti- tude can not be heard at the ground - is this true? If true, then what is the minimum altitude necessary for supersonic aircraft to achieve in order that their booms not be heard?
henry@zoo.toronto.edu (Henry Spencer) (06/20/89)
From: henry@zoo.toronto.edu (Henry Spencer) >... the author claimed that the sonic boom of an SR-71 (at cruising alti- >tude can not be heard at the ground - is this true? ... Audibility of sonic booms on the ground seems to be a very complicated function of altitude, aircraft configuration, atmospheric conditions, phase of the Moon :-), etc. Studies of making the boom of a commercial SST inaudible tend to end up requiring cruising altitudes of 100,000+ ft., which are unlikely even for the SR-71. (Its highest unclassified cruise is 70-something, and the difference between that and 100 is awfully large to be just secret performance margin.) Henry Spencer at U of Toronto Zoology uunet!attcan!utzoo!henry henry@zoo.toronto.edu
jkj@hpfchabu.hp.com (Jim Jackson) (06/24/89)
From: hplabs!jkj@hpfchabu.hp.com (Jim Jackson)
Well I have heard it! Place OL-8. Time a tdy from Beale. How do
I know it was SR71 tail #97x? Well they dumped fuel as they flew
over and we could see the fuel trail but not the aircraft, so time
later the soft boom (actually two closely spaced booms or so it
seemed).
It has been too long to me to remember the details, but I seem to
recall it was a "training" flight that also celebrate a milestone
and a large stuffed Snoopy went along with the RSO. I was off at the
time, I was on the night shift and didn't meet the aircraft when
it returned, but I do remember seeing a picture of the Pilot and RSO
with a large Snoopy dog.
People in western Colorado complain about the sonic booms from SR's
but I believe those are from tanking operations.
The alt records fo the SR are about 82000 feet as I recall. The speed
is above mach 3. My Coffee cups have a big 3+ on them. I would
sure like to get more. I got the ones I still have from the
tech rep's building at Beale, $0.40 each, I said it's been a long time
Jim Jackson (Former USAF Tsgt. Electronic sensor repairman)shafer@drynix (Mary Shafer) (06/27/89)
From: Mary Shafer <shafer@drynix> Jim Jackson wrote: > People in western Colorado complain about the sonic booms from SR's > but I believe those are from tanking operations. Refueling is subsonic--KC-135s and KC-10 can only go about 0.85 Mach. Perhaps Jim refers to the SRs descending and slowing to rendevous. > The alt records fo the SR are about 82000 feet as I recall. The speed > is above mach 3. My Coffee cups have a big 3+ on them. I would > sure like to get more. I got the ones I still have from the > tech rep's building at Beale, $0.40 each, I said it's been a long time They sell SR-71 mugs (and a lot of other aircraft & shuttle stuff) at the Dryden Exchange Gift Shop (P.O. Box 86, Edwards, CA 93523 (805) 258-3954) but they just have a picture of the A/C, no writing. They used to sell the ones with the 3+, but no more. I think the mugs are about $4, but the B-2 is a little more. They have a catalog and do mail order. M F Shafer |Ignore the reply-to address NASA Ames-Dryden Flight Research Facility |Use shafer@elxsi.dfrf.nasa.gov NASA management doesn't know what I'm doing and I don't know what they're doing, and everybody's happy this way.
sampson@killer.DALLAS.TX.US (Steve Sampson) (06/27/89)
From: sampson@killer.DALLAS.TX.US (Steve Sampson) I've seen the SR-71 on radar many times (they squawk mode 3/A 44xx when above 60,000 per IFR sup) when I fly to the west coast. They're usually doing Mach over the states. Since this is a normal routine - then the complaints must be small. When I was stationed in Fortuna ND (Near Crosby north of Williston) we heard a boom just about every monday. Every monday except when the turkey farmers didn't post a NOTAM - prohibiting supersonic for the duration of egg laying or whatever turkeys do...
tarquin@zen.co.uk (Ian Mitchell ) (06/30/89)
From: tarquin@zen.co.uk (Ian Mitchell )
In article <7785@cbnews.ATT.COM> sampson@killer.DALLAS.TX.US (Steve Sampson) writes:
:
:I've seen the SR-71 on radar many times (they squawk mode 3/A 44xx when
:above 60,000 per IFR sup) when I fly to the west coast. They're usually
:doing Mach over the states. Since this is a normal routine - then the
:complaints must be small. When I was stationed in Fortuna ND (Near Crosby
:north of Williston) we heard a boom just about every monday. Every monday
:except when the turkey farmers didn't post a NOTAM - prohibiting supersonic
:for the duration of egg laying or whatever turkeys do...
The SR71 does Mach overland? I didn't know that? How come Concorde can't?
No flames please, this isn't a major gripe, I'm just a patriotic Brit who
thinks Concorde is just as beautiful as the SR71 (or F14 for that metter).
Tarqs