From: skunk-works-digest-owner@mail.orst.edu To: skunk-works-digest@mail.orst.edu Subject: Skunk Works Digest V5 #431 Reply-To: skunk-works-digest@mail.orst.edu Errors-To: skunk-works-digest-owner@mail.orst.edu Precedence: bulk Skunk Works Digest Thursday, 21 September 1995 Volume 05 : Number 431 In this issue: Re: Arrestor Hooks Re: F-117 call signs Re: GPS UAV over Bosnia British F-117 C-130s on carriers Jet Engine vs. Rockets Re: Engines Re: Does a small space glider exist? Re: F-117 call signs Re: Jet Engine vs. Rockets SR-71 Patch Re: Lessons from the cancelled A-12 Re: Lessons from the cancelled A-12 Re: F-117/U-2/C-130s on carriers Of units & water Re: Lessons from the cancelled A-12 Re: Convair's Blackbird Competitor? Re: Lessons from the cancelled A-12 Killed near Bakersfield 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: John Burtenshaw Date: Thu, 21 Sep 1995 09:27:55 -0100 Subject: Re: Arrestor Hooks At 13:46 20/09/95 MDT, Dennis Overgard wrote:- > The arresting hooks on Air Force aircraft are used to prevent >excursions off the end of runways. I once had the priveledge of >belonging to an Air Force flying club and taking instruction at >an ANG Base. The flight instructor was extremely firm about not >landing short on the runway because the arresting cable at the >runways end would rip the undercarriage off the Cessna 152 we >were flying. An F-104 pilot I talked to at an airshow told me >that the arresting hook on the 104 he was flying was for the >same purpose. RAF Flt Lt John Peters states in his book Team Tornado that the arrestor hook on the Tornado does exactly that (stop the aircraft from going off the end of the runway) but is useless above any speed higher than 175mph (as far as I can recall)as it would simply pull the back of the Tornado from the rest of the fuselage. It is, however, very good for use in small airfields when combined with the thrust-reversers of the Tornado engines. The undercarriage of the Tornado is pretty strong and I would think that it could fly from carriers (if Britain had any big deckers left :-( ) Regards John =========================================================================== John Burtenshaw Systems Administrator, The Computer Centre, Bournemouth University - --------------------------------------------------------------------------- Postal Address: Talbot Campus, Fern Barrow, POOLE, Dorset, BH12 5BB U.K. Internet: jburtens@bournemouth.ac.uk Phone: 01202 595089 Fax: 01202 513293 AX.25: g1hok@gb7bnm.#45.gbr.eu. AMPRnet: g1hok.ampr.org. (44.131.17.82) CompuServe: 100336,3113 =========================================================================== ------------------------------ From: John Burtenshaw Date: Thu, 21 Sep 1995 09:36:18 -0100 Subject: Re: F-117 call signs At 22:35 20/09/95 EDT, you wrote: >Kathryn and Andreas -- > >In answer to your question about how the F-117's are assigned radio callsigns: > >The truth is I don't think we know for sure. I'll forward your post to the comm >monitors listserv and see what response we get. In the mean time, after having >monitored this stuff for several years my opinions are: > >(1) most tactical calls for ACC aircraft seem to be based on the either the >mission and/or the unit and probably not based on the pilots or crew. For >example the Brit F-117 jockey (whose accent is of course quite distiguishable) ^^^^ >has been heard using several different calls although he usually is heard using >SPEAR ##. > This is really news! The RAF have refused to confirm or deny that they have anyone flying the F-117 although they did let it be known that they wanted to lease some F-117s from the USAF. Not sure what happened to that idea? Regards John =========================================================================== John Burtenshaw Systems Administrator, The Computer Centre, Bournemouth University - --------------------------------------------------------------------------- Postal Address: Talbot Campus, Fern Barrow, POOLE, Dorset, BH12 5BB U.K. Internet: jburtens@bournemouth.ac.uk Phone: 01202 595089 Fax: 01202 513293 AX.25: g1hok@gb7bnm.#45.gbr.eu. AMPRnet: g1hok.ampr.org. (44.131.17.82) CompuServe: 100336,3113 =========================================================================== ------------------------------ From: marco.giaiotto@pmn.it (Marco Giaiotto) Date: Thu, 21 Sep 1995 13:03:45 +0200 Subject: Re: GPS > >I have two more thing to clarify: > >1. How can the receiver clock be so precise ? >2. How is the position actually evaluated ? > OK. Let's try and answer both questions. All satellites carry three atomic clocks (worth 100,000 $ each...), so they are very precise. In addition the GPS ground stations are allowed to correct them (and to correct the orbit too) twice a day. To make things simple, imagine we are in a bi-dimensional world, a sheet of paper. Draw a dot on the sheet of paper. That is the satellite. Let's assume that the receiver clock is precise. When you receive the time transmitted by the satellite, you can evaluate the transmission delay. Being the transmission speed very well known (...), you know your distance from the satellite. In a tri-dimensional world you identify a sphere, but let's continue with the bi-dimensional example. Knowing the distance from the satellite (the dot) you know you are on a circle (i.e. by definition all the points on a circle have the same distance from the center). We still don't know our position. Have you drawn the circle ? Please do it. You are somewhere on that circle... Draw another dot outside the circle, more or less the distance of half a diameter: that is another satellite. It is the same thing: you evaluate the delay and the distance from the satellite, so you can draw another circle. This circle intersecates the previous one in two points (draw it carefully... two circles can intersecate in 0, 1 or 2 points: draw the last case.). You are on one of those points, but you still don't know which one, so you need a third satellite. Draw it. Same procedure: evaluate the delay, draw a circle, and the circle must pass on one of the previous points (my advice is to draw the dots representing the satellites at 120 degrees to keep things simple). So far so good. You identified your position on the sheet of paper. In a tri-dimensional world you would need four satellites, but the procedure would be the same (It is the reason why you need only three satellites to evaluate the position of a ship and four for a plane: the ship is virtually in a bi-dimensional world, being the fourth globe the earth). Now suppose that the receiver clock isn't precise (the real situation). You evaluate a wrong delay, i.e. a wrong distance. A wrong distance means wrong diameters for your circles. Suppose you have a longer diameter. Your three circles will intersecate in different points (take your previous drawing, increase the diameters of half a centimeter, and you will isolate a triangle-like area. You are somewhere in that area). The diameter error is the same for all circles, because it is due to your clock error, so you can try to adjust your clock until you identify a single point. This can be done by approximation, or processing the data you have just evaluated. Of course the GPS receiver processes the data. At this point your clock is regulated, but the receiver continuously checks its precision. A word about GDOP (Geometric Diluition Of Precision). I suggested you should draw your circles at 120 degrees to keep things simple. If you didn't follow my advice, your triangle is very flat, and your evaluation of your position very poor. The same applies to the real satellites: if they are in "good" position, the correction your receiver can do is very good. Otherwhise it is very poor. So, your receiver tracks more than four satellites (up to twelve) and chooses the ones in the best position. This affects the accuracy of your measurement and is indicated by the GDOP or PDOP (Position) or VDOP (Vertical) display of your receiver: the smaller the figure, the more accurate the measurement. If you need to perform the differential correction, you have to acquire all the visible satellites with your fixed receiver, due to the fact that you don't have any idea of which satellites the on-board receiver is choosing. I hope it is clear enough. If it is not, do not hesitate to ask. Ciao, Marco Date: Thu, 21 Sep 1995 07:30:25 -0500 Subject: UAV over Bosnia Well, now the bombing of the Serbs in Bosnia is over for now. I will not delve into the political/moral issues of the civil war in that region. Instead I thought that you would like to know that the news media captured on film a UAV flying over Bosnia. The reporter simply called it a spy plane and made no mention of it being a UAV. I am not a UAV expert, so I am not certain exactly what kind was shown. However it did look like the Tier 2 General Atomics Predator due to the distinctive downward pointing V-tail. Paul \ ___ / Paul Adams \ /___\ / paul@erc.msstate.edu ____________\___/__.__\___/____________ YF-22 \ \ / / \__/\___/\__/ ------------------------------ From: seb@tadpole.co.uk (Steven Barber) Date: Thu, 21 Sep 1995 14:20:49 +0100 Subject: British F-117 I'm told that at a recent UK air display (RAF Waddington?), the F-117 display was flown by a USAF pilot on day 1 and an RAF pilot on secondment to the USAF on the second. Apparently there are RAF pilots being rotated through the F-117 detachment to ensure several are trained in how to fly the Nighthawk. My informant has promised to look up the rest of the data he got at the show & bring it in. Anyone got any suggestions for where UK F-117 flights might head? 8-) Steve Barber These statements have absolutely nothing to do with my employer. ------------------------------ From: (SSG, ANTHONY, MAA, 565) Date: Thu, 21 Sep 95 7:05:36 PDT Subject: C-130s on carriers >Sounds like they should carry rocket assists or something similar for >getting back home. C-130's can be fitted with a Assisted TakeOff (ATO) units. Eight units of 1000# thrust each are fitted to the sides of the a/c of the jump door air deflectors. I would think it would be a good idea to use these for a carrier T/O if I were on the subject aircraft! Tony ------------------------------ From: "Terry Colvin" Date: Thu, 21 Sep 95 08:13:38 EST Subject: Jet Engine vs. Rockets Forwarded from SPACE TECH list: Date: Wed, 20 Sep 1995 04:47:39 GMT From: "Dean R. Oberg" Subject: Jet engine first stages In article , ederd@bcstec.ca.boeing.com (Dani Eder) writes: > >Last year we studied a jet-boosted launcher using P&W F100-229 >jet engines (the engine in the F-15 fighter). It works just fine, >taking you up to 50,000 ft and Mach 1.7. Since this engine on >full afterburner has about 4 times the fuel efficiency of a rocket >engine, your best performance is achieved by running pure jet >propulsion until you run out of air, then dropping the jets and >lighting the rocket engines. I just re-discovered an article detailing a Solid Fuel Ram-Jet developed by NOTS (Naval Ordinance Test Station) in 1959 that may make a good "second" stage. No moving parts, burned fuel "briquettes" as they were referred to in the article by H. Powell Jenkins Jr. (Astronautics, Dec. 1959, Pg.44-45). Claimed combustion efficiency of 90%. Operational range was Mach 1.5-4.5, thus it would need to have a first stage boost to this speed. How about a regular oxidizer-added grain to start, then the ram-jet and fnish off with a liquid oxidizer injected after the air runs out at altitude. Three stages in one! - -- (Dean R. Oberg) ------------------------------ From: larry@ichips.intel.com Date: Thu, 21 Sep 1995 09:24:12 -0700 Subject: Re: Engines >A few clarifications: >The flow at the end of the combustion chamber, not the nozzle, cannot >exceed Mach 1. The flow at the exit of the combustion chamber does exceed Mach 1 in a scramjet running in scramjet mode. Just to clarify for those who might be puzzled. Larry ------------------------------ From: "Terry Colvin" Date: Thu, 21 Sep 95 09:27:28 EST Subject: Re: Does a small space glider exist? ______________________________ Forward Header __________________________________ Subject: Re: Does a small space glider exist? Author: djenkins at smtp-fhu Date: 21/9/1995 8:01 AM >I wonder if a smaller spacecraft could use Naiobium (Columbium) for the >outer shell rather than the ceramic tiles of the STS Orbiter..I understand >that this was considered for the Orbiter, but worked out to be too >expensive. Alan "HOTOL" Bond's Skylon SSTO proposal would use an AEA >ceramic composite reinforced with silicon carbide fibre called System 2 >for the aeroshell to reduce maintenance..sounds like a very good idea to >me. I don't know how much you know about Skylon, but it's well worth >looking into. Any idea where I can get some data on the Skylon proposal? I am in the process of updating my Space Shuttle book for early next year and would like to include some of the 'future concept' data in the last chapter. TIA, DJ - ---------------------------------------------------------------- "indecision may, or may not, be my problem" | djenkins@iu.net - Jimmy Buffett | - ---------------------------------------------------------------- ------------------------------ From: mangan@Kodak.COM (Paul Mangan) Date: Thu, 21 Sep 95 12:52:47 EDT Subject: Re: F-117 call signs My son was a CAPs officer on an AWACS. He says they use different call signs depending on whether they are in or out of the country and often reassigned when in combat (the Gulf War). While on one of the training exercises near Groom (alias the box or the black box) they had some fun with some F117s by pretending to see them when they couldn't. Got them guys pretty upset. But that's about the most fun they had other than listening to one of the guys get chewed out and sent home after he went in the "box" Paul mangan@kodak.com Dave says: > > Kathryn and Andreas -- > > In answer to your question about how the F-117's are assigned radio callsigns: > > The truth is I don't think we know for sure. I'll forward your post to the comm > monitors listserv and see what response we get. In the mean time, after having > monitored this stuff for several years my opinions are: > > (1) most tactical calls for ACC aircraft seem to be based on the either the > mission and/or the unit and probably not based on the pilots or crew. For > example the Brit F-117 jockey (whose accent is of course quite distiguishable) > has been heard using several different calls although he usually is heard using > SPEAR ##. > > (2) the number seems to be associated with day/operation/mission (or a 'flight') > and probably not the pilot or crew. However, the AMC a/c (the old MAC) usually > use the generic callsign REACH followed by the actual tail number of the > aircraft for routine flights. There are a lot of variations on this theme > however. > > Coincidently, as I am typing this I just heard the Brit up on UHF using SPEAR > 24. I have logged him using many different SPEAR ##'s but the numbers are always > digits in the 10's or 20's. The numbers always seem to be sequential during any > given (training) mission. For example I might hear SPEAR 21, 22, 23, 24, 26 up > at the same time with BURNER 12, 13, 14, etc. You get the picture. > > F-117 callsigns heard operating around Holloman the past year or so include: > > BANDIT, BRAHMA, BURNER, CHAPS, CHEETAH, CRISPY, FLEX, HAIL, ICE, JAVA, JEEP, > RAIN, RAM, RIDER, SHADY, SNOW, SPEAR, SPOOKY, and VAPOR. > > (As I write this SPEAR, SPOOKY, JAVA and CHEETAH flights are up on UHF getting > ready to areal refuel with UTAH 52, a KC-135 from the 151st ARG, Utah ANG. > During the refuel SPOOKY 04 gives his tail number tothe boom operator as 810793) > > I'll let you know what I hear from some of the other guys on the military > monitoring listserv. > > Dave > > ------------------------------ From: Charles_E._Smith.wbst200@xerox.com Date: Thu, 21 Sep 1995 09:55:00 PDT Subject: Re: Jet Engine vs. Rockets That does sound interesting. The only problem is it would be expensive. You would have to accelerate the entire vehicle to required velocity. This means lots o` dollars. One of the first concepts you learn as a budding rocket scientist is stage optimization. These are the "Pi" ratios. The basic concept is that you have structural mass that becomes dead weight as fuel is burned. It is most economical, therefore, to discard it. If it can be asset recovered and reused the all the better. The computations are actually quite easy. You determine the payload, the altitude, and the velocity you want at shutoff- and plug and chug. As you probably guessed, the formulas are exponential, and as such extremely easy to use. They are path dependent, also. It might seem more efficient at first glance to fire straight up, and then turn 90 deg and fire for velocity as you coast up. It turns out not. Oh yeah, I forgot. Another parameter is max acceleration. The previous gedanken experiment should show the problem. You can`t very well have a manned vehicle accelerating at 640 ft/sec x sec!!! Since you dropped the unused mass, you now can use a smaller motor for the next stage. Since you have a smaller motor you need less fuel- less lift-off weight and hence a cheaper boost. This means more profit for the commercial launch company ar lower taxes for the citizens if it a gov. agency. Either is a prime concern in design phase. Also, you want to keep the tanks as small as possible to avoid chugging. The demands of the regenerative jackets on the nozzles may change as ambient conditions change. You really don`t need to run those big launch turbines at 500K feet, do you? The problem with the proposed "mutimode" motor is that the different oxidizers set up different acoustic conditions. With any solid fuel motor acoustics is a prime consideration. There is a nasty mode of operation called "screaming" that can cause total failures in the motors. (It has been suggested that the Challenger may have had a screaming instability prior to seal failure.) Oops, here comes the boss. Got to fly. Chuck ------------------------------ From: dougt@u011.oh.vp.com (Doug Tiffany) Date: Thu, 21 Sep 95 13:23:41 EDT Subject: SR-71 Patch Does anyone in Skunkville know where I can purchase the patch that commemorates the reactivation of the SR-71? I saw the patch while visiting Kathryn and Adreas Gers-Pahl's home page: http://www.umcc.umich.edu/~schnars/ I've gotten a couple of leads, but nothing concrete. Thanks in advance. - -- A hundred years from now, it will not matter what kind of house I live in, how much is in my bank account, or what kind of car I drive, but the world may be a different place because I was important in the life of a child. Douglas J. Tiffany dougt@u011.oh.vp.com Varco-Pruden Buildings Van Wert, Ohio ------------------------------ From: sschaper@pobox.com (Steve Schaper) Date: Thu, 21 Sep 1995 13:03:22 -0500 Subject: Re: Lessons from the cancelled A-12 All I know is what I read in AvLeak. The A-12 sounded great. I also know an aerospace engineer who has seen what is left of the A-12. No details were given of course, secrecy was kept, but it did/does exist. ------------------------------ From: kuryakin@arn.net (Rick Pavek) Date: Thu, 21 Sep 1995 15:02:49 -0500 Subject: Re: Lessons from the cancelled A-12 +All I know is what I read in AvLeak. The A-12 sounded great. I also know an +aerospace engineer who has seen what is left of the A-12. No details were +given of course, secrecy was kept, but it did/does exist. I spoke to one of the engineers on the project... He said that after it was cancelled they packed up all the airframes (some near completion), the spares, the tooling, everynd shipped them off to parts unknown. It was presumed to be Lockheed. I certainly believe it's alive. Rick Rick Pavek | Get Windows '95!! It's kuryakin@arn.net | the last Microsoft game Graphics and HTML for hire | you'll _ever_ want to Play! http://northshore.shore.net/~wxcentrl/uncle/index.html ------------------------------ From: clarence@spooky.chinalake.navy.mil (Clarence Dent) Date: Thu, 21 Sep 1995 14:34:27 -0800 Subject: Re: F-117/U-2/C-130s on carriers Brad Swanson wrote: >Do you know of a good site for a picture of a C-17? > >Thanks, > >Brad Swanson >!NTERPRISE Networking Services from U S West > I've got a couple of pictures, but I don't remember where I got them from. It seems to me that a friend had borrowed a CD ROM from someone with a bunch of military pictures on it and I just 'borrowed' them from there. I've collected some photos by going to the Edwards air show, which should be coming up in a few weeks. I don't know the exact date, but the PA person from there would know if you called information and talked to them. I would gladly send you copies of these, but I haven't had any luck with Uulite on this new mail server. The pictures always get damaged beyond repair, and I haven't had time to figure out why. Soon hopefully. Good luck in your endeavors...Anyone else got an answer? Unfortunately I can't reply directly back to Brad through my server. Clarence@spooky.chinalake.navy.mil "Jet Noise: The sound of a paycheck" ------------------------------ From: "I am the NRA." Date: Thu, 21 Sep 95 15:40:11 PDT Subject: Of units & water (moderately off toppic, but brief:) 1) The length/beam ratio that limits boat speed does not limit a/c speed. Air is a compressible medium. Water is an incompressible medium. They react differently. (OK. There's handwaving in that, but that's why...) 2) The units in the l/b constant don't match because its an empirical relationship. If one goes thru ALL the math, i guess it can be restated so the units match... (Ob-mil_if_not_skonk) L/B ration was quanitifed when the navies, notably British, started to build torpedo-boat-destroyers (now just called destroyers) ca 1900. They found that even arbitrarily large amounts of power would not push a displacement hull above a speed determined by its l/b ratio. It was expensive learning, as a number of full size destroyers were built which Did Not Work.) regards dwp ------------------------------ From: sschaper@pobox.com (Steve Schaper) Date: Thu, 21 Sep 1995 19:29:30 -0500 Subject: Re: Lessons from the cancelled A-12 This siting was at MD in St. Louis, some time back, though. ------------------------------ From: larry@ichips.intel.com Date: Thu, 21 Sep 1995 18:21:05 -0700 Subject: Re: Convair's Blackbird Competitor? Paul Suhler writes: >Convair, as well as Lockheed, submitted a design to the CIA under >Project Gusto in the late 1950s. Actually, GUSTO was Lockheed's name. Convair's name was not GUSTO. I know that's what "The OXCART Story" says, but it is not correct as far as the total truth regarding the Convair bid is concerned. > Lockheed won and the Blackbird was >the result. Does anyone know anything about the Convair design? I know some things about it. I wish I knew more. I've always been fascinated about it and I would just LOVE to see a drawing of both of Convair's proposals or design directions, if you will. If you love high speed designs like I do, you'd like these designs. I don't care who publishes it, I'd just love to see them, assuming that's legal. But it might not be time yet. After Convair lost the design in 1959, the designs were placed in the Convair classified safe in Fort Worth. In the mid-70's (also the time of HAVE BLUE) Convair's customer sent several people down to Convair and retrieved the designs. They left nothing. There used to be design reports, models, photos of mockups, etc. All that was removed. Yes there were two design directions. The numbers in The OXCART History represent the last of the Convair bids, the one Convair called KINGFISHER. > All >I've ever seen were some projected performance figures in a Crickmore >book. What did the thing look like? Both Convair bids were deltas, of course. That should come as no surprise. Some day someone will hit the mother load, I hope! I really hope Convair's customer didn't destroy the work! Oh to see those designs! Larry ------------------------------ From: kuryakin@arn.net (Rick Pavek) Date: Thu, 21 Sep 1995 20:45:42 -0500 Subject: Re: Lessons from the cancelled A-12 At 19:29 9/21/95, Steve Schaper wrote: +This siting was at MD in St. Louis, some time back, though. DOH! Of course. Rick Rick Pavek | Get Windows '95!! It's kuryakin@arn.net | the last Microsoft game Graphics and HTML for hire | you'll _ever_ want to Play! http://northshore.shore.net/~wxcentrl/uncle/index.html ------------------------------ From: chosa@chosa.win.net (Byron Weber) Date: Thu, 21 Sep 1995 18:27:38 Subject: Killed near Bakersfield Anyone have any details on pilots from the 4450th Tactical Test Group killed July 11, 1986 near Bakersfield and October 14, 1987 at Nellis. Names? What were they flying? What was the cause? Anything. Thanks Byron ------------------------------ End of Skunk Works Digest V5 #431 ********************************* To subscribe to skunk-works-digest, send the command: subscribe skunk-works-digest in the body of a message to "majordomo@mail.orst.edu". 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