From: skunk-works-digest-owner@mail.orst.edu To: skunk-works-digest@mail.orst.edu Subject: Skunk Works Digest V5 #494 Reply-To: skunk-works-digest@mail.orst.edu Errors-To: skunk-works-digest-owner@mail.orst.edu Precedence: bulk Skunk Works Digest Thursday, 2 November 1995 Volume 05 : Number 494 In this issue: SR-71 before Mach 1 Re: SR-71 before Mach 1 Anotherthought on 71 drag!!! Sorry, slightly off topic!! Re: HAVE BLUE ENGINE TYPE Re: AHAA vehicle (As-Heavy-As-Air) Re: SR-71 before Mach 1 The Oxcart Story Re: HAVE BLUE ENGINE TYPE F-117 crash report Articles of note Re: ridgies Have Blue Photos Re: SR-71 before Mach 1 Re: SR-71 before Mach 1 Re: SR-71 before Mach 1 Re: AHAA vehicle (As-Heavy-As-Air) Skunk Works History Re: SR-71 before Mach 1 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: Wei-Jen Su Date: Thu, 2 Nov 1995 03:06:26 -0500 (EST) Subject: SR-71 before Mach 1 Hello all!!! Last weekend, I was listening my Aerospace Profesor about flight characteristics, and he came out with one interesting characteristic of the SR-71. He said that the SR-71 before it reach the Mach 1, the drag is so strong that the airplane has to dive first (using the help of the gravity) to break the sound barrier (Mach 1). After reaching Mach 1, the drag will reduce again. Any comments??? May the Force be with you Su Wei-Jen E-mail: wsu02@barney.poly.edu ------------------------------ From: Charles_E._Smith.wbst200@xerox.com Date: Thu, 2 Nov 1995 04:02:07 PST Subject: Re: SR-71 before Mach 1 Called the "drag divergence Mach number". Lots of aero-bodies show this. The drag spikes as the Mach number gets close to unity. Since the Kutta Joukowski theorem explains subsonic lift you can see that as the velocity of the A/C approaches Mach 1, there are going to be places on the upper surface of the wing where the air goes supersonic. This creates a shock wave on the upper surface of the wing. Now you get compression on top of the wing and the increase in pressure from low to high in virtually no distance causes problems with the flow. Once you get past transonic all the flow is supersonic everywhere. Angle of attack and wing cross section cause Prandtl-Meyer expansion effects to create the pressure delta from upper to lower surface , hence lift. The "supercritical" airfoils (NACA 64 series if my memory serves,) were developed by Whitcomb (et. al) to lower the drag divergence. Notice that these airfoils have a noticably flat upper profile. This was done to keep the velocity differences well distributed. Remember, for all its aura, the SR-71 is a pretty simple A/C in aerodynamic terms. Its a delta. Deltas aren`t real sensitive to airfoil shape, only thickness. The delta creates low speed lift by having a "inefficient" flow near the L.E. The drag divergence can be complicated. Since the `71`s engines aren`t terribly efficient- due to the low hrp of the fuel- using a little potential to kinetic conversion for the jump to compression lift seems very likely. Chuck ------------------------------ From: Charles_E._Smith.wbst200@xerox.com Date: Thu, 2 Nov 1995 04:12:56 PST Subject: Anotherthought on 71 drag!!! Hey, I just had a great idea! Some of the students out there in aerospace can have some real fun. I guess every aero student gets aquainted with Dan Raymer`s software these days. ( Rutan is using it!!) Model the fuselage (easy) model the nacells (even easier) the wing ( a nit) and the rudder/fins (RDS does twin tails!) and do an analysis. Post the results for us. Realize that, RDS probably far surpasses anything the Skunk Works had available in those days. We can probably get a realistic range, stall speed, runway req. and cost to build one today from such an analysis. We can even get the FAR part 25 data! Any takers out there for such a project? if you know the S/W it should only take a couple of eves. Chuck ------------------------------ From: jstone@iglou.com (John Stone) Date: Thu, 2 Nov 1995 07:35:51 -0500 Subject: Sorry, slightly off topic!! Hi, There's a move afoot to get a commemerative stamp for Francis Gary Powers. I was asked by his son to post some address' so that if you feel that there should be a stamp, you could voice that to the Post Office. Thanks. >Fransis Gary Powers >Commemorative >US Postage Stamp >Letters of Support to Issue >The Stamp May be Addressed to: >Citizen Stamp Advisory Committee >475 L'enfant Plaza SW, Rm 5301 >Washington, DC 10260-2420 Thanks for your help, 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/ ------------------------------ From: BaDge Date: Thu, 2 Nov 1995 08:24:23 -0500 (EST) Subject: Re: HAVE BLUE ENGINE TYPE On Wed, 1 Nov 1995, Ralph the Wonder Llama wrote: > >HI! > > Does anyone know what type of engines the "HAVE BLUE" F-117A prototype > >used?? I heard engines from a T-38 were used but I'm not sure. Considering > > According to the book I have, the Have Blue prototypes used J85 engines, as > used in the F-5 fighter (and probably the T-38 as well, since the two are > Speaking of Have Blue, does anyone know if there are pictures of this > aircraft anywhere on the net? Oddly, it seems to be more classified than > the F-117 itself.... I know I've seen this on the Net, but one place I saw it has since tightened up, alas. Jane's site used to have most of it's ATWA on line, and I saw it there. (It's certainly available in back volumes at the lib.) Also, I was a bit frustrated, wanting to reply to the poster's orig. question, since I was away from my books, and didn't want to give an imprecise answer. Thus I searched Lycos on "F117" and about 10 links later, found, at least, the engine type for the NH, and that HB was a GE. The Aerospace community is certainly well rep. on the WWW. In fact it was such an 'embarrassment of riches', that my difficulty was weeding through all of it to find the NH/HB. ;-) I notice Andreas is planning a new section which should cover the internals on most of the aircraft we discuss around here. regards, ________ BaDge ------------------------------ From: "J. Pharabod" Date: Thu, 02 Nov 95 14:33:21 MET Subject: Re: AHAA vehicle (As-Heavy-As-Air) >Together with the existance of the Russian 'Thermoplane' POC vehicle, it >seems to me that one of my favorite 'black programs', the 'Senior Citizen', >might well be: > - a 'manta-ray'/'triangular'-shaped, > - sometimes silent flying or hovering, > - sometimes relatively fast flying, > - relatively big, > - probably stealthy AHAA vehicle, >Andreas Gehrs-Pahl (Tue, 31 Oct 1995 16:47:18 -0500 (EST)) I beg your pardon? This is exactly the craft which has flown over half of Belgium from November 1989 to (at least) mid-1991. And please, don't tell me that this is off charter. I myself inquired in Belgium, heard, saw and discussed with witnesses, inquired inside the Royal Military School in Brussels. IMHO, this is not extra- terrestrial, this is the most skunky event within the last 10 years (or the greatest aeronautical hoax in all times). J. Pharabod ------------------------------ From: "David \"Scre^2ch\" Prieto" Date: Thu, 2 Nov 1995 09:32:39 -0500 (EST) Subject: Re: SR-71 before Mach 1 Yes I did some work on this 2 years ago, designing supercritical airfoils approaching Mach 1 from .864 As you approach Mach 1 the air over the airfoil increases in velocity and in some areas will exceed Mach 1 this creates stability problems along with shockwaves and huge amounts of drag. The supercritical airfoils are very thin and tend to have a flat profile. They generate low lift at subsonic speeds but perform well at transonic speeds. These airfoils allow aircraft such as the 747 and other new transonic civilian transports to cruise at such speeds without wasting huge amounts of fuel. I have yet to learn a high enough level of differential equations before I can even think about comprehending the mathematics behind these airfoils though. Also there is a code that was developed to create a full 3-D wings for supercritical airfoil section designed by the code I used. The airfoil code was called HODO, and the wing code was called FLO22. FLO22 was capable of creating a complete wing in any configuration that you chose. Unfortunately I never was given the opportunity to use it as it wasn't 100% complete at the time. But I have seen some of the wings it outputted and they looked VERY interesting. One had ripples running chordwise along the wing. It looked like... those potato chips.. ridgies? (is that what they are called?) Well anyway that's all I can remember about it for now. If anyone wants just ask me, I'll try to dig up some references sometime. ***************************************************************************** David "Scre^2ch" Prieto 14/3 dpriet01@barney.poly.edu screech@cnct.com TIP#814 ***************************************************************************** On Thu, 2 Nov 1995, Wei-Jen Su wrote: > > Hello all!!! Last weekend, I was listening my Aerospace Profesor > about flight characteristics, and he came out with one interesting > characteristic of the SR-71. He said that the SR-71 before it reach > the Mach 1, the drag is so strong that the airplane has to dive first > (using the help of the gravity) to break the sound barrier (Mach 1). > After reaching Mach 1, the drag will reduce again. > Any comments??? > > May the Force be with you > > Su Wei-Jen > E-mail: wsu02@barney.poly.edu > > ------------------------------ From: Paul Suhler Date: Thu, 2 Nov 1995 06:41:32 -0800 (PST) Subject: The Oxcart Story I've read a copy of "The Oxcart Story," which has circulated online. Does anyone know when it was written and where it comes from? The only information in it is the name of the purported author, Thomas P. McIninch. In it, the author claims that on the first A-12 mission over North Vietnam, the aircraft was never detected by radar. Crickmore claims that it was, which caused consternation in Langley and Burbank, after all the effort at reducing RCS. Is Crickmore's information later and more accurate? The no detection story is repeated in Pace's "The Lockheed Skunk Works." Thanks, Paul Suhler ------------------------------ From: clarence@spooky.chinalake.navy.mil (Clarence Dent) Date: Thu, 2 Nov 1995 07:02:21 -0800 Subject: Re: HAVE BLUE ENGINE TYPE >From: Ralph the Wonder Llama >Subject: Re: HAVE BLUE ENGINE TYPE > >Speaking of Have Blue, does anyone know if there are pictures of this >aircraft anywhere on the net? Oddly, it seems to be more classified than >the F-117 itself.... > >- - Michael Well, Mike, the only pictures I've seen were in Aviation Week a few years ago. I also remember seeing a picture or drawing in the Aerofax book about the F-117. If someone knows of some photos on the net somewhere, I'd like to see them myself. I haven't seen the aforementioned pictures for years, and it seems to me that the tails were canted inwards, which caused a stability problem that couldn't be overcome without the tail configuration being redesigned to outward facing attitude... Clarence Dent Do you mean to tell me there are places where you _don't_ have to water every day just to keep plants alive?... ------------------------------ From: Kathryn & Andreas Gehrs-Pahl Date: Thu, 2 Nov 1995 10:45:11 -0500 (EST) Subject: F-117 crash report The following is paraphrased from AP news reports: Jane's Defense Weekly reported yesterday, Wednesday, they obtained the accident report of the last F-117A crash through FOIA from the USAF aircraft accident investigation board. The most likely cause of the crash of F-117A '822' on May 10, 1995, in the foothills of the Zuni Mountains in northwest New Mexico, was a fault in the automatic pilot system that disoriented the pilot. The aircraft was on a night training mission, and was off course and appeared to have hit the ground in a steep dive, traveling at 644 mph. The F-117A (costing $46 million) and the pilot Capt. Kenneth W. Levens, were assigned to the 9th FS (Fighter Squadron), 49th FW (Fighter Wing) at Holloman AFB, near Alamogordo, NM. The board found no evidence that the pilot tried to eject, but investigators do not believe he crashed intentionally. The crash report states, that engineers said the aircraft was operating normally when it went down. In the most likely scenario, the automatic pilot failed to follow the preplanned route, a failure that is apparently quite common in F-117s! Levens probably did not notice right away that the autopilot had failed and when he did, he most likely over-banked the aircraft. He did not immediately use his cockpit instruments to level the aircraft because he probably was substantially disoriented. Jane's also wrote, that the F-117's instrument layout is such that the pilot could easily have blocked the attitude indicator, which gives the aircraft's relationship to the horizon. [I am not sure, with what he could have blocked it, though.] - -- 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: George Allegrezza 02-Nov-1995 1018 Date: Thu, 2 Nov 95 10:34:36 EST Subject: Articles of note The October 1995 Air International has the concluding article of David Baker's two-part series on stealth. While there is little of interest in the text, there are two photos of wind tunnel models of the General Dynamics Kingfish(er) Mach 6 concept: -- A complete model, including the B-58 launch vehicle and the two-component Kingfish(er) system. -- A model of the manned component, which looks remarkably like modern hypersonic vehicle designs. (Look, I'm making bulleted lists like Andreas now. :-) ) The captions imply that Kingfish(er) development was halted because of concerns about the ability of the B-58 to achieve the required launch speed (M>2) due to the drag from the belly-mounted Kingfish(er) system. One wonders if this was the genesis of the proposed B-58 variant with four J58s. Also, the September/October 1995 Air Enthusiast has an article on the competing designs for the British TSR.2 (GOR 339) program in the early 1960s. While not stealth designs, the various proposals detail the UK industry's efforts to deal with the low level/high speed penetration problem envisioned for nuclear conflicts. Some of the designs, like the Fairey double-delta, are especially attractive. There is also a short recap of the sad history of the TSR.2 program. George George Allegrezza | Digital Equipment Corporation | "Why don't they just shut up and Mobile Systems Business | take their ass-whipping like men?" Littleton MA USA | allegrezza@ljsrv2.enet.dec.com | -- Charles Barkley ------------------------------ From: Greg Fieser Date: Thu, 2 Nov 1995 10:00:02 -0600 Subject: Re: ridgies I believe the correct technical term here is "ruffles".... (i.e. "rrrrruffles have rrrrridges...) > One had ripples running chordwise along the wing. It looked like... > those potato chips.. ridgies? (is that what they are called?) Greg Fieser (hey! plagarism was MY idea!!!) ------------------------------ From: Mike Freeman Date: Thu, 2 Nov 1995 11:12:55 -0500 Subject: Have Blue Photos - ------ =_NextPart_000_01BAA914.DF92F460 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Speaking of Have Blue, does anyone know if there are pictures of this aircraft anywhere on the net? Oddly, it seems to be more classified = than the F-117 itself.... - - - Michael michaelg@alpha2.csd.uwm.edu There is a Skunk Works page, and I think they had photos of it. There = were VERY few pictures of that thing. Oddly enough, there is quite a bit = of video footage of it though. I'm not sure of the Skunk Works page's = address, but you can find it with WebCrawler or Yahoo. 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Climb up subsonic, dive through the transonic, and pull up supersonic. We don't call it the sound barrier, we call it the transonic regime. The sound barrier terminology dates from the '40s and is not used amongst those of us working the the field. Only the uninformed use the older term. 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, 2 Nov 1995, Wei-Jen Su wrote: > > Hello all!!! Last weekend, I was listening my Aerospace Profesor > about flight characteristics, and he came out with one interesting > characteristic of the SR-71. He said that the SR-71 before it reach > the Mach 1, the drag is so strong that the airplane has to dive first > (using the help of the gravity) to break the sound barrier (Mach 1). > After reaching Mach 1, the drag will reduce again. > Any comments??? > > May the Force be with you > > Su Wei-Jen > E-mail: wsu02@barney.poly.edu > ------------------------------ From: Mary Shafer Date: Thu, 2 Nov 1995 13:55:37 -0500 (EST) Subject: Re: SR-71 before Mach 1 We accept it as being in the tomato/tomahto class for speech mannerisms. It's the barrier part we get testy about. 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, 2 Nov 1995, BaDge wrote: > > On Thu, 2 Nov 1995, Mary Shafer wrote: > > > The maneuver is called the dipsydoodle. Climb up subsonic, dive through > > the transonic, and pull up supersonic. > > > > We don't call it the sound barrier, we call it the transonic regime. The > > sound barrier terminology dates from the '40s and is not used amongst > > those of us working the the field. Only the uninformed use the older term. > > > Er... what do you call us, who call it the "transonic region"? ;-) > > > regards, > ________ > BaDge > > > ------------------------------ From: Charles_E._Smith.wbst200@xerox.com Date: Thu, 2 Nov 1995 11:04:13 PST Subject: Re: SR-71 before Mach 1 Gee, I must be uninformed, along with all the engineers I work with, people at test facilities, and professer emeritus types I know. We also never call engines "axial flow compression high bypass turbofans with mixed exhaust streams of the Rankine type of turbomachinery". We call them "fans". We also don`t say "I was dissapointed with the Harper-Cooper qualities of this planform/configuration." We say "flys really nice" or "what a dog" or something like that. I`ve even heard a real live test pilot say "what a peice of shit" . My favorite bad approach/landing euphamism is "Bohemien Cluster Fuck" , or BCF`s when the full name isn`t pollitically correct. Sound barrier is meerly technoslang for Mjustunder1. :-) Chuck ------------------------------ From: larry@ichips.intel.com Date: Thu, 2 Nov 1995 11:07:35 -0800 Subject: Re: AHAA vehicle (As-Heavy-As-Air) >>Together with the existance of the Russian 'Thermoplane' POC vehicle, it >>seems to me that one of my favorite 'black programs', the 'Senior Citizen' >>might well be: >> - a 'manta-ray'/'triangular'-shaped, >> - sometimes silent flying or hovering, >> - sometimes relatively fast flying, >> - relatively big, >> - probably stealthy AHAA vehicle, >>Andreas Gehrs-Pahl (Tue, 31 Oct 1995 16:47:18 -0500 (EST)) J. Pharabod replies: >I beg your pardon? > >This is exactly the craft which has flown over half of Belgium from >November 1989 to (at least) mid-1991. I understand your quandry here, but is it really? Please describe the flight characteristics of the Belgium object again? Are they concistent with a LTA/AHAA (whatever) vehicle? Larry ------------------------------ From: Greg Fieser Date: Thu, 2 Nov 1995 14:14:18 -0600 Subject: Skunk Works History I have just spoken with Jay Miller, and he will soon be subscribing to the list. Someone recently posted a question about the logo on Jay's "Skunk Works History" book. Jay told me that the logo was designed by Lockheed to commemorate the 50th anniversary of the Skunk Works. Jay also mentioned that the book has been revised and updated, and the new release does not feature the aforementioned logo. His F-117A and B-2A mini-books have also been updated and rereleased, too. I don't have the specifics of what changed in the contents, and I don't mean for this to sound like a shameless plug for Jay's books, but these books are excellent reference material for the subject at hand. Greg Fieser ------------------------------ From: larry@ichips.intel.com Date: Thu, 2 Nov 1995 10:36:53 -0800 Subject: Re: SR-71 before Mach 1 > Hello all!!! Last weekend, I was listening my Aerospace Profesor >about flight characteristics, and he came out with one interesting >characteristic of the SR-71. He said that the SR-71 before it reach >the Mach 1, the drag is so strong that the airplane has to dive first >(using the help of the gravity) to break the sound barrier (Mach 1). >After reaching Mach 1, the drag will reduce again. > Any comments??? As others have said, what your professor was really teaching was drag divergence mach no, and others have described it well. As far as the statement about the SR-71 is concerned, I don't believe he is correct, as far as a standard clean A-12 or SR-71 is concerned. This is actually an interesting subject so I will make a few observations here and if I'm wrong, then I'll learn something too! Anyway, another thing you'll notice is that the SR is not area-ruled at all. I believe this is probably true because the engines used in the airplane were quite capable of pushing it supersonic without area ruling, unlike many of the supersonic aircraft designed in that same era. I believe that the SR has no problem going supersonic in level flight or even in a climb, given those magnificent bleed-bypass turbojets it has (J-58s) in the + 30,000 lb. thrust (w AB) class. What the professor was probably talking about, maybe without knowing it, was the MD-21 configuration or other dirty configurations of either the A-12 or SR-71. It is well known that the MD-21 had a terrible time accelerating to supersonic. I have been told by guys involved with the MD program that supersonic speed was attained in a steep dive (very steep - vertical?). There were also more powerful J-58's intended for the SR that the MD program office (2 USAF guys actually - the assigned USAF LCOs) appropriated for the MD to see if it would help with the acceleration problem in the dirty configuration. Actually, many high speed aircraft designs have problem going supersonic because of there high base drag configurations. This is why external burning for base drag reduction is (was I guess - sad!) such a big topic for these aircraft. Larry ------------------------------ End of Skunk Works Digest V5 #494 ********************************* 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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