From: skunk-works-digest-owner@mail.orst.edu To: skunk-works-digest@mail.orst.edu Subject: Skunk Works Digest V5 #490 Reply-To: skunk-works-digest@mail.orst.edu Errors-To: skunk-works-digest-owner@mail.orst.edu Precedence: bulk Skunk Works Digest Monday, 30 October 1995 Volume 05 : Number 490 In this issue: Undeliverable Message Re: Report: U.S. May Use Big Blimp Re: Report: U.S. May Use Big Blimp Questions looping mail Re[2]: Report: U.S. May Use Big Blimp airships/cfit Some more GPS (and the last one, I think) LTA See the end of the digest for information on subscribing to the skunk-works or skunk-works-digest mailing lists and on how to retrieve back issues. ---------------------------------------------------------------------- From: Date: Mon, 30 Oct 95 4:54:02 EST Subject: Undeliverable Message To: Cc: Subject: Skunk Works Digest V5 #489 Message not delivered to recipients below. Press F1 for help with VNM error codes. VNM3043: Howard German@BSC@IBK VNM3043 -- MAILBOX IS FULL The message cannot be delivered because the recipient's mailbox contains the maximum number of messages, as set by the system administrator. The recipient must delete some messages before any other messages can be delivered. The maximum message limit for a user's mailbox is 10,000. The default message limit is 1000 messages. Administrators can set message limits using the Mailbox Settings function available in the Manage User menu (MUSER). When a user's mailbox reaches the limit, the user must delete some of the messages before the mailbox can accept any more incoming messages. - ---------------------- Original Message Follows ----------------------Skunk Works Digest Monday, 30 October 1995 Volume 05 : Number 489 In this issue: Undeliverable Message Report: U.S. May Use Big Blimp U.S. to halt Bosnia spyplane flights - Albania Re: Looking for this aviation poem... SR-71 CIA pilot (fwd) See the end of the digest for information on subscribing to the skunk-works or skunk-works-digest mailing lists and on how to retrieve back issues. - ---------------------------------------------------------------------- From: Date: Sun, 29 Oct 95 4:34:36 EST Subject: Undeliverable Message To: Cc: Subject: Skunk Works Digest V5 #488 Message not delivered to recipients below. Press F1 for help with VNM error codes. VNM3043: Howard German@BSC@IBK VNM3043 -- MAILBOX IS FULL The message cannot be delivered because the recipient's mailbox contains the maximum number of messages, as set by the system administrator. The recipient must delete some messages before any other messages can be delivered. The maximum message limit for a user's mailbox is 10,000. The default message limit is 1000 messages. Administrators can set message limits using the Mailbox Settings function available in the Manage User menu (MUSER). When a user's mailbox reaches the limit, the user must delete some of the messages before the mailbox can accept any more incoming messages. - - ---------------------- Original Message Follows ----------------------Skunk Works Digest Sunday, 29 October 1995 Volume 05 : Number 488 In this issue: Undeliverable Message SR-71 CIA pilot Re: SR-71 CIA pilot See the end of the digest for information on subscribing to the skunk-works or skunk-works-digest mailing lists and on how to retrieve back issues. - - ---------------------------------------------------------------------- From: Date: Sat, 28 Oct 95 4:47:15 EDT Subject: Undeliverable Message To: Cc: Subject: Skunk Works Digest V5 #487 Message not delivered to recipients below. Press F1 for help with VNM error codes. VNM3043: Howard German@BSC@IBK VNM3043 -- MAILBOX IS FULL The message cannot be delivered because the recipient's mailbox contains the maximum number of messages, as set by the system administrator. The recipient must delete some messages before any other messages can be delivered. The maximum message limit for a user's mailbox is 10,000. The default message limit is 1000 messages. Administrators can set message limits using the Mailbox Settings function available in the Manage User menu (MUSER). When a user's mailbox reaches the limit, the user must delete some of the messages before the mailbox can accept any more incoming messages. - - - ---------------------- Original Message Follows ----------------------Skunk Works Digest Saturday, 28 October 1995 Volume 05 : Number 487 In this issue: SR-71 at Nellis Re: Blackbird goes travelling See the end of the digest for information on subscribing to the skunk-works or skunk-works-digest mailing lists and on how to retrieve back issues. - - - ---------------------------------------------------------------------- From: Kathryn & Andreas Gehrs-Pahl Date: Fri, 27 Oct 1995 05:55:42 -0400 (EDT) Subject: SR-71 at Nellis SR-71A, article '2018', USAF serial '64-17967', tail number '17967', one of the reactivated, USAF-operated aircraft, landed on Wednesday, October 25, 1995, at Nellis AFB, after the NASA crew experienced an in-flight fuel transfer problem over Nevada, while on the way back to Palmdale, CA. They elected to land at Nellis AFB, Las Vegas, NV, because they didn't want to risk running out of fuel. The aircraft created two loud sonic booms over Las Vegas, when she came in at about 05:15 p.m. PST. She was apparently scheduled to return to Palmdale on Thursday, October 26, 1995, at 04:30 p.m. PST, but seemed to have experienced more problems, and is still there. The aircraft is apparently visible from outside of the air base, and will probably try to return to Palmdale, later today (Friday, October 27, 1995). Nellis AFB is right now quite busy, because the exercise Gunsmoke '95 is currently held there, lasting from October 26 to October 29. [Info compiled from r.a.m and Tim Gerlach, Las Vegas] - - - - -- Andreas - - - - --- --- Andreas & Kathryn Gehrs-Pahl E-Mail: schnars@ais.org 313 West Court St. #305 or: gpahl@raptor.csc.flint.umich.edu Flint, MI 48502-1239 Tel: (810) 238-8469 WWW URL: http://www.umcc.umich.edu/~schnars/ - - - - --- --- - - - ------------------------------ From: Mary Shafer Date: Fri, 27 Oct 1995 14:16:41 -0400 (EDT) Subject: Re: Blackbird goes travelling Fuel transfer problems, it turns out. Had enough fuel onboard, but couldn't pump it to a tank the engines could draw from. In defense of Dryden's maintainence folks, this is one of the reactivated birds, maintained down in Palmdale by Lockheed. Regards, Mary Mary Shafer DoD #0362 KotFR shafer@ursa-major.spdcc.com URL http://www.dfrc.nasa.gov/People/Shafer/mary.html Some days it don't come easy/And some days it don't come hard Some days it don't come at all/And these are the days that never end.... On Thu, 26 Oct 1995, Dean Adams wrote: > > Mary sez: > > Right now (Thursday morning) there's a Blackbird at Nellis AFB. They hope > > to recover it fairly soon, though, so don't dawdle. > > Sounds interesting! How about the "rest of the story"? :) > > - - - ------------------------------ End of Skunk Works Digest V5 #487 ********************************* To subscribe to skunk-works-digest, send the command: subscribe skunk-works-digest in the body of a message to "majordomo@mail.orst.edu". If you want to subscribe something other than the account the mail is coming from, such as a local redistribution list, then append that address to the "subscribe" command; for example, to subscribe "local-skunk-works": subscribe skunk-works-digest local-skunk-works@your.domain.net To unsubscribe, send mail to the same address, with the command: unsubscribe skunk-works-digest in the body. Administrative requests, problems, and other non-list mail can be sent to either "skunk-works-digest-owner@mail.orst.edu" or, if you don't like to type a lot, "prm@mail.orst.edu A non-digest (direct mail) version of this list is also available; to subscribe to that instead, replace all instances of "skunk-works-digest" in the commands above with "skunk-works". Back issues are available for anonymous FTP from mail.orst.edu, in /pub/skunk-works/digest/vNN.nMMM (where "NN" is the volume number, and "MMM" is the issue number). - - ------------------------------ From: Wei-Jen Su Date: Sat, 28 Oct 1995 21:02:01 -0400 (EDT) Subject: SR-71 CIA pilot Hello Skunkers...Just some interesting question: Some missions of the SR-71 are flown by CIA pilots... Does they have any relation with the Air Force pilots? They are actually Air Force pilots that work for the CIA or they are CIA agents that have some special training to become SR-71 pilots???? And why the pilots must be from CIA???? I will appreciate your answer and discussions... May the Force be with you Su Wei-Jen wsu02@barney.poly.edu - - ------------------------------ From: jstone@iglou.com (John Stone) Date: Sat, 28 Oct 1995 22:08:37 -0500 Subject: Re: SR-71 CIA pilot Wei-Jen, > Hello Skunkers...Just some interesting question: Some missions of >the SR-71 are flown by CIA pilots... Does they have any relation with the >Air Force pilots? They are actually Air Force pilots that work for the >CIA or they are CIA agents that have some special training to become >SR-71 pilots???? The pilots that flew the SR were USAF pilots. The CIA flew A-12's, which were flown by civilain pilots (actually USAF pilots lent to the CIA, but being paid by the CIA and not the USAF or DoD. They went through a course of instruction to learn to fly th A-12 at Groom Lake, NV (Area 51). > And why the pilots must be from CIA???? > I will appreciate your answer and discussions... Because the CIA was operating these planes. They used a similar process to "sheep dip" the pilots, like want Gary Powers and his compatriots went through before under going training to fly the U-2. Hope this helps, John Stone | / ^ \ ___|___ -(.)==<.>==(.)- --------o---((.))---o-------- SR-71 Blackbird U-2 Dragon Lady John Stone jstone@iglou.com john.stone@shivasys.com U-2 and SR-71 Web Page http://wl.iglou.com/blackbird/ - - ------------------------------ End of Skunk Works Digest V5 #488 ********************************* To subscribe to skunk-works-digest, send the command: subscribe skunk-works-digest in the body of a message to "majordomo@mail.orst.edu". If you want to subscribe something other than the account the mail is coming from, such as a local redistribution list, then append that address to the "subscribe" command; for example, to subscribe "local-skunk-works": subscribe skunk-works-digest local-skunk-works@your.domain.net To unsubscribe, send mail to the same address, with the command: unsubscribe skunk-works-digest in the body. Administrative requests, problems, and other non-list mail can be sent to either "skunk-works-digest-owner@mail.orst.edu" or, if you don't like to type a lot, "prm@mail.orst.edu A non-digest (direct mail) version of this list is also available; to subscribe to that instead, replace all instances of "skunk-works-digest" in the commands above with "skunk-works". Back issues are available for anonymous FTP from mail.orst.edu, in /pub/skunk-works/digest/vNN.nMMM (where "NN" is the volume number, and "MMM" is the issue number). - ------------------------------ From: Kathryn & Andreas Gehrs-Pahl Date: Sun, 29 Oct 1995 08:53:16 -0500 (EST) Subject: Report: U.S. May Use Big Blimp I found the following article on ClariNet, forwarded here without permission. A model photo and a small article about the blimp mentioned here, can be found in the Lockheed Martin Skunk Works Star magazine, Vol. 5, No. 7, of July 28, 1995. The article is titled: "Glasgow, Wexler are inventors of year, fifteen other patent holders announced", and lists mainly patents for LTAVs (Lighter-Than-Air Vehicles) and VSTOL (Vertical/Short Take-Off and Landing) transports: LONDON (AP) -- The U.S. military is considering building a giant blimp to transport troops and cargo to future crisis zones, Jane's Defense Weekly reported. Saturday's edition of the magazine said a 1,485-foot blimp is one of several radical proposals being considered by the Pentagon to prevent a repeat of logistic problems during the Gulf War. Although U.S. Air Force C-5 and C-141 cargo planes were able to move troops quickly to Saudi Arabia after the Iraqi invasion of Kuwait in 1990, it took many weeks for tanks and other heavy equipment to arrive. "Using a fleet of airships, each with a potential 500 ton lifting capacity, the Joint Chiefs of Staff would be able to guarantee a fully capable military response to any future act of aggression in days, rather than weeks," Jane's said. The idea is that each airship should be able to move a platoon of four armored fighting vehicles and their personnel, the magazine said. A Pentagon spokesman, who was not identified, was quoted as saying the Defense Department and the Joint Chiefs had received some unsolicited proposals for large airships, and they were being considered along with other alternatives. Jane's said several companies have discussed their airship designs with the Pentagon and the Joint Chiefs including the Lockheed Martin Skunk Works, which did secret work on the Stealth aircraft. Fred Ferguson, chairman of the Pan Atlantic Aerospace Corp. of Ontario has already held discussions with the U.S. military about his company's proposed 1,485-foot blimp, Jane's said. It would be twice the length of the largest airship ever built, Nazi Germany's Hindenburg, which exploded over Lakehurst, N.J., in 1937. Jane's said the Worldwide Aeros Corp. of California, in partnership with Westinghouse Airship Industries, is planning to start construction of a sub-scale airship prototype in the next few months. Westinghouse is also involved in another team concept from Germany, the magazine said. - - -- Andreas - - --- --- Andreas & Kathryn Gehrs-Pahl E-Mail: schnars@ais.org 313 West Court St. #305 or: gpahl@raptor.csc.flint.umich.edu Flint, MI 48502-1239 Tel: (810) 238-8469 WWW URL: http://www.umcc.umich.edu/~schnars/ - - --- --- - ------------------------------ From: Kathryn & Andreas Gehrs-Pahl Date: Sun, 29 Oct 1995 08:56:21 -0500 (EST) Subject: U.S. to halt Bosnia spyplane flights - Albania Another article forwarded from ClariNet (without permission): TIRANA, Albania (Reuter) - The United States will halt unmanned reconnaisance flights over Bosnia from a base in northern Albania early next month, Albanian daily Koha Jone reported Saturday. The three "Predator" aircraft stationed at Gjader airbase, whose spying missions have already been scaled down to just one flight a day, will be grounded on November 5, the paper quoted Albanian military sources as saying. The aircraft, which are said to be undetectable by radar, are guided by remote control. They were stationed in Albania in July. U.S. diplomats in Albania declined to comment on the report. - - -- Andreas - - --- --- Andreas & Kathryn Gehrs-Pahl E-Mail: schnars@ais.org 313 West Court St. #305 or: gpahl@raptor.csc.flint.umich.edu Flint, MI 48502-1239 Tel: (810) 238-8469 WWW URL: http://www.umcc.umich.edu/~schnars/ - - --- --- - ------------------------------ From: "Randall Clague" Date: Sun, 29 Oct 1995 21:47:29 -0800 Subject: Re: Looking for this aviation poem... LURK MODE OFF Yes, it's off topic, but some might enjoy it... I think this is from MCAS El Toro's monthly mag, about '88 or '89. LOW FLIGHT Oh, I have slipped the surly bonds of Earth, And hovered out of ground effect on semi-rigid blades; Earthward I've auto'ed, and met the rising brush Of non-paved terrain -- and done a thousand things You would never care to -- skidded and drooped and flared Low in the hear soaked roar. Confined there, I've chased the earthbound traffic And lost the race to insignificant headwinds. Forward, and a little up, in ground effect I've topped the General's hedge with drooping turns Where never Skyhawk, nor even Phantom flew. And, shaking and pulling collective, I've lumbered The low trespassed halls of Victor Airways, Put out my hand, and touched a tree. LURK MODE ON - ------------------------------ From: megazone@world.std.com (MegaZone) Date: Sun, 29 Oct 1995 23:58:38 -0500 (EST) Subject: SR-71 CIA pilot (fwd) Once upon a time Wei-Jen Su shaped the electrons to say... > Hello Skunkers...Just some interesting question: Some missions of >the SR-71 are flown by CIA pilots... Does they have any relation with the I don't know where you heard this. The CIA operated the A-12 Blackbird, but the USAF used the SR-71 Blackbird. What evidence do you have that the CIA flew the USAF's SR-71? - - -MZ - - -- megazone@world.std.com 510-527-0944 MegaZone's Waste Of Time Moderator: anime fanfic archive, ftp.std.com /archives/anime-fan-works; rec.arts.anime.stories - Maintainer: Ani Difranco Mailing List - Mail to majordomo@world.std.com with 'subscribe ani-difranco' in the body. - ------------------------------ End of Skunk Works Digest V5 #489 ********************************* To subscribe to skunk-works-digest, send the command: subscribe skunk-works-digest in the body of a message to "majordomo@mail.orst.edu". If you want to subscribe something other than the account the mail is coming from, such as a local redistribution list, then append that address to the "subscribe" command; for example, to subscribe "local-skunk-works": subscribe skunk-works-digest local-skunk-works@your.domain.net To unsubscribe, send mail to the same address, with the command: unsubscribe skunk-works-digest in the body. Administrative requests, problems, and other non-list mail can be sent to either "skunk-works-digest-owner@mail.orst.edu" or, if you don't like to type a lot, "prm@mail.orst.edu A non-digest (direct mail) version of this list is also available; to subscribe to that instead, replace all instances of "skunk-works-digest" in the commands above with "skunk-works". Back issues are available for anonymous FTP from mail.orst.edu, in /pub/skunk-works/digest/vNN.nMMM (where "NN" is the volume number, and "MMM" is the issue number). ------------------------------ From: Charles_E._Smith.wbst200@xerox.com Date: Mon, 30 Oct 1995 04:07:01 PST Subject: Re: Report: U.S. May Use Big Blimp There is alot more to this than meets the eye. I was asked at one point to do a quick study on feasability, possibly leading to a research project. The use of aero-gels and VHBP fans might could form the technology base for a new breed of airships with 200kts+ cruise. (This is when I became aware of the similarities of submarines and airships which I alluded to a while back.) As with all airships, the term "lighter than air" is incorrect. Airships are heavier than air, but not very. I`ve witnessed the Goodyear America make over a 1000` takeoff run on a hot afternoon. I digress... The use of aero-gel material would [possibly] allow a superlight airframe with a much more efficient shape than the old NACA 0024 torpedo. A neat CFD model was based on a manta ray. (Equivavent Re at cruise, I figured Mother Nature was a good start.) The big problem with a ship of this size is vibration. You get into "flapping" problems in a hurry. Also, as span goes up, so does minimum turn radius. Flapping would almost surely make Lockheed -Martin the people to see. Lockheed`s got the most experience. The wings on the C-5 will flap right off at some airspeeds if the aerodamping is turned off. Ever seen films of the wings when they turn it off? WOW! Must be a scary feeling watching those engines twist through +/- 15 deg.!! Again, I digress.... The Idea had some merit, but the Soviet approach is really vastly superior. Their solution is HUGE ground-effects aircraft. These are very low aspect ratio transports with engines out the kazoo. Flying very close to the water (or desert?) they can use smaller wings. The Soviet design can also make brief excursions into the .5 to 1K ft. altitude region. This has 2 real benefits. 1) Much higher speed. 2)The technology ( and the craft now) exist. The biggest problem with any airship from a tactical standpoint is that they are just a little hard to hide, and they are sitting ducks in a war. The civilian possiblities look brighter. I would love to design an aerial cruise ship. Be fun, huh? Chuck ------------------------------ From: David Windle Date: Mon, 30 Oct 1995 15:30:16 Subject: Re: Report: U.S. May Use Big Blimp Chuck wrote: >As with all airships, the term "lighter than air" is incorrect. Airships >are heavier than air, but not very. I`ve witnessed the Goodyear America >make over a 1000` takeoff run on a hot afternoon. I'm not quite with you there Chuck. It's with some trepidation that I take you up on this matter as you're an aerospace engineer :) But here goes nothin'...It's my understanding that small LTAs, like the Goodyear and Fuji blimps, use a t/o run to overcome their relatively poor lift and low ballast levels. For those on the list who aren't into LTA, it should be pointed out that LTA craft suffer from loss of useful lift in hot weather as hot air being less dense than the cool variety means that the ship diplaces less of it and becomes relatively heavy. I once had a flight in Goodyear's Europa during a glorious English summer, which involved quite a long take off run, but a flight in a Fuji ship late in the year entailed a very short t/o run. However... the big rigids were "weighed off" in their hangars so that they were in equilibrium. When the command "Up Ship" was given, ballast would be dumped and the ship rose straight up - aerostatically. To save ballast it was flown aerodynamically when it was well clear of terra firma. Airships have always used their hulls as crude aerofoils. >Flapping would almost surely make Lockheed -Martin the people to see. >Lockheed`s got the most experience. The wings on the C-5 will flap right >off at some airspeeds if the aerodamping is turned off. Ever seen films of >the wings when they turn it off? WOW! Must be a scary feeling watching >those engines twist through +/- 15 deg.!! Again, I digress.... Let's not forget that Lochkheed had plans for a small rigid lifting body shaped airship in the 80s using a stiff composite hull. >The Idea had some merit, but the Soviet approach is really vastly superior. >Their solution is HUGE ground-effects aircraft. > >These are very low aspect ratio transports with engines out the kazoo. >Flying very close to the water (or desert?) they can use smaller wings. The >Soviet design can also make brief excursions into the .5 to 1K ft. altitude >region. >This has 2 real benefits. >1) Much higher speed. >2)The technology ( and the craft now) exist. >The biggest problem with any airship from a tactical standpoint is that they are >just a little hard to hide, and they are sitting ducks in a war. I'm not sure that a huge WIG/Ekranoplane flying at 300 knts in ground effect would be any less difficult to hide,or less of a sitting duck, though I understand that the class 3 types are capable of flying high enough for the Soviets to be seeking ICAO approval for them....well out of G/E ! But I agree, they're less of a technological risk than airships for military use. Though something of a potential nightmare for IMO safety regs. I understand that a delegation of US congressmen visited the Gorki plant and were charged 133,000 for a demo flight in the Caspian Sea Monster Ekranoplane a while back...seems the Soviets have the technology would no funding. >The civilian possiblities look brighter. I would love to design an aerial >cruise ship. Be fun, huh? Now you're talking. I spoke to someone who had flown on both the Graf and Hindenburg about their cruises to the US and I've never been so jealous of anyone in my life. Before anyone shouts "off charter"..I *did* mention Lockheed :) Best D ------------------------------ From: RHOEFELM Date: Mon, 30 Oct 1995 10:20:50 -0400 (EDT) Subject: Questions In the thread on lighter than air, heavy lift vehicles, Chuck mentioned "aero-gels", "flapping" and "aero-damping". May I please have some more information on these items? TIA, Ralph S. Hoefelmeyer rhoefelm-cos3@kaman.com Dire_Wolf 70436.511@compuserve.com ------------------------------ From: Kean Stump Date: Mon, 30 Oct 1995 09:52:13 -0800 (PST) Subject: looping mail A pox on broken mailers that don't behave like they should! Arrrrghh! There, I feel better now... I've temporarily removed "Howard German" from the digest until he fixed his mailbox. kean Kean Stump Information Services kean@ucs.orst.edu Oregon State University OSU doesn't pay me to have official opinions. (503)-737-4740 ------------------------------ From: "Terry Colvin" Date: Mon, 30 Oct 95 12:26:07 EST Subject: Re[2]: Report: U.S. May Use Big Blimp "Chuck" said: > As with all airships, the term "lighter than air" is incorrect. > Airships are heavier than air, but not very. Now, I am not an aeronautical engineer, just a dumb peter pilot. So I usually don't get into theoretical discussions. Still ... I have operated from airfields where various "blimps" have operated. They were always tied to their mooring mast when not flying. If they are really "heavier than air, but not very" it seems to me that they would, when not under power, settle to the ground. Not float at the peak of the mast. I am always ready to learn something new. If someone can explain how something heavier than air can float in the air, please educate me. For now, I will maintain my current understanding: the net result of the amount of the weight of the aircraft, the ballast, and the helium in the cells will be just the opposite. The blimp will be "lighter than air, but not very." Bill Riddle Skeptical Army Aviator (Retired) ------------------------------ From: "I am the NRA." Date: Mon, 30 Oct 95 12:52:43 PST Subject: airships/cfit >As with all airships, the term "lighter than air" is incorrect. That would come as a heckuva shock to the folks who operated the Hindenburg, et al. (some the ops manuals have been reprinted, in translation.) >Airships are heavier than air, but not very. Sometimes. Like a submarine, they can be statically positive or negative buoyant and dynamically positive or negative. And whether they are statically positive or negative varies with external air temp/humidity, etc and lift gas temp as well as the obvious matters of ballast, gas purity, fuel load etc.... It was typical to lift off heavy, possibly flying off, to have max fuel available AND max ballast, because the ship got lighter as fuel was burned off. (Water recovery, etc, omitted for brevity...) >I`ve witnessed the Goodyear America make over a 1000` takeoff run on a hot >afternoon. Yep. True story from Graf Zeppelin's Round the World Cruise: They were in Frisco(Moffit?). Next step was over the rockies. Tricky, as an airship has a design pressure height, lower than rockies, in this case. Ship was lightened, extraneous crew and spares sent by rail to nest stop etc, etc. Lift off was for first thing in t he morning, involved "flying off" dynamically. Problem is there were High Voltage lines at end of field. Cdr(?) Eckert made his run. As lines approached, popped the nose UP clearing the lines, then DOWN toggling the tail up. Literally JUMPED the ship over 'em. Rest of the trip was without incident..... ================================= In the Circumlocutions Contest: An FAA report on a certain FlybyWire fault included the phrase: ....may result in premature contact with the ground... A reporter asked: Does that mean "crash"? (This was written up in comp.risks, at the time....) regards dwp ------------------------------ From: Marco Giaiotto Date: Mon, 30 Oct 1995 22:09:50 +0100 Subject: Some more GPS (and the last one, I think) Hi. It's a long time since I posted two messages about GPS. In my opinion, the topic was not fully covered, and it will probably never be, but I have some nore stuff. GPS is not really related to skunk-works topic, but at least is interesting for aviation enthusiasts, so please forgive me. (BTW, I would not know where to post it...) I hope this mail can help to clarify almost everything concerns a simple use of GPS. It cannot be a linear speech, because the topics are different, but I'll do the best I can. - - Speed. A GPS receiver gives its position, but also its speed. Somebody thinks that the speed is evaluated from the distance between two fixes. It isn't. The GPS receiver evaluates the doppler shift of the incoming signal, i.e. it is able to discriminate the doppler contribution of your speed over the one due to the speed of the satellite (it is worth reminding that GPS satellites have a low orbit, 22,000 km, and complete a orbit every twelve hours). - - Health. The signal transmitted by the satellites includes information about the health of each satellite composing the constellation (when complete 28 SV, 24 operative and 4 spare). The receiver is able to exclude from its processing the defective ones. - - Position. Planet earth isn't a sphere, but similar to an ellipsoid. GPS receivers process the position in a tri-axial coordinates system earth-centered, so X axis begins at the center of the earth and points the North Pole; Y axis begins at the center of the earth and points the equator at 0 degrees; Z axis begins at the center of the earth and points the equator at 90 degrees. The coordinates are then converted to Longitude, Latitude, Altitude, referred to a standard ellipsoid called WGS84, not to the actual earth surface, so GPS altitude could be different from true altitude, since the ellipsoid is a regular one and planet earth isn't. - - Time. The GPS time started in .... (could anyone add the date ?) and was synchronized to UTC (Universal Time Coordinated). Since then, planet earth slowed down its rotation, and UTC was corrected. GPS time wasn't, so we have to take into account this shift. It is transmitted as a piece of information contained inside the satellite signal, and today it's equal to 10 seconds. A further second is expected on December, 31st, 1995. - - NANUs NANUs are short reports about the GPS constellation healt, maintenance, elapsed second and so on. They are available on the web (I don't remember now the adresses, I have them at my office), but you can use the Lycos robot to find them: use "NANUS" and "GPS" as keywords in "and" configuration. There are two sites, one in USA and one in Europe. The European site issues a newsletter (unfortunately in German) available in electronic and smail form (for free). From the NANUS sites you can find many links to lots of GPS stuff. OK, this is the end of my off-topic. I just want to clarify that everything I wrote about GPS is public domain. I simply collected the relevant data and put them in a readable form (at least I hope it is readable). If you think I can be of any help in clarifying what I wrote, feel free to contact me. I will answer (if i can) to you directly and to the list, should the topic be of general interest. If I won't be able to answer, please accept my apologies since now. Ciao, Marco ------------------------------ From: Charles_E._Smith.wbst200@xerox.com Date: Mon, 30 Oct 1995 13:34:03 PST Subject: LTA Yep, Everybody got it right and didn`t even know it! The density of helium being less than air, Archimede`s principle says the helium will result in bouyancy. The net bouyant force on a modern airship is just a little less than the weight. Why? Good question. Reason #1. Since area = huge, there isn`t a heck of a lot of dynamic pressure required to get lift in the tons range, even with low Cl. #2. Mooring. When moored, i.)the velocity gradient of the wind, ii.)the increase in enthalpy- well, let me put it in human terms- the flow gets slowed by the mooring mast (some linear momentum gets turned into angular momentum). The net result of these two things -> V uppersurface exceeds V lowersurface. We all know what happens next. The opposite - a suckdown can occur in a crosswind, but thats a whole different story altogether. Yes, these ships can operate very happily when lighter than air, but things go very much easier when they are slightly heavier. You have to figure it this way. You`ll never have it perfect. If you are lighter than air you fly with the nose down to keep level. If you are a little heavier you keep the nose up. Never having flown an airship I can only guess that a little weight makes things alot easier near the ground. The other operational consideration in propeller placement. When you gun the engines close to the ground you get a suckdown. With a gear located on the CG you get a nice rotation and off she goes. I`m told latest blimps use vectored thrust and can achieve near vertical takeoffs. The problem with vertical takeoffs is obvious to most aero-minded types. You are flying at 90 deg. angle of attack. The stability derivatives of a conventional airship tell you this situation won`t go on for very long!!! So you end up with forward velocity anyway. Chuck ------------------------------ End of Skunk Works Digest V5 #490 ********************************* To subscribe to skunk-works-digest, send the command: subscribe skunk-works-digest in the body of a message to "majordomo@mail.orst.edu". If you want to subscribe something other than the account the mail is coming from, such as a local redistribution list, then append that address to the "subscribe" command; for example, to subscribe "local-skunk-works": subscribe skunk-works-digest local-skunk-works@your.domain.net To unsubscribe, send mail to the same address, with the command: unsubscribe skunk-works-digest in the body. 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