From: skunk-works-digest-owner@harbor.ecn.purdue.edu To: skunk-works-digest@harbor.ecn.purdue.edu Subject: Skunk Works Digest V2 #56 Reply-To: skunk-works-digest@harbor.ecn.purdue.edu Errors-To: skunk-works-digest-owner@harbor.ecn.purdue.edu Precedence: bulk Skunk Works Digest Tuesday, 19 January 1993 Volume 02 : Number 056 In this issue: Re: Aerospace Sciences Meeting AW&ST Re: AW&ST B2 note Blackbird notes 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: "Charles A. Lind" Date: Mon, 18 Jan 1993 08:18:20 -0500 Subject: Re: Aerospace Sciences Meeting Just a couple of comments about 2 recent posts. George Allegrezza writes, regarding a comment by Mary Shafer: >Did you get a chance to attend the two sessions on waveriders (chaired by >Anderson and Lewis, I believe)? If so, what did you think of the >presentations? Was there anything of interest to the (reasonably) >intelligent lay person who is interested in hypersonic aircraft? I'm >considering ordering a few of the papers from the AIAA, but it's always >hard to predict just how interesting something might be from the title in >the Bulletin. > >On the other hand, at $3.50 a pop, I won't go bankrupt, and I might learn >something anyway. Some of the authors listed are *the* heavy hitters in >the hypersonics business. There might even be a pretty picture, or a >nested reference to same. There were 2 waverider sessions, one chaired by Mark Lewis of the Univerisity of MD (that's us) and the other chaired by John L. Anderson, from NASA Headquarters. I believe most of the presentations are not for the lay person. However, the paper by John D. Anderson, Jr. and Mark Lewis should be general enough to satisfy most people (this was in the first session AIAA#0399). Mary Shafer responds: >I went to the second session (Lewis's). After the last paper Mr. Waverider >himself spoke briefly and it was very interesting. I'd like to just clear this up a bit. Mark Lewis, although he is my major advisor and although he does do work in the area of hypersonic waveriders, should not be individually marked as being the waverider person, to do so would be right to all those involved. MANY people have contributed to the concept of waveriders. Nonwieller, if anyone, is Mr. Waverider. At the University of MD, where over 80% of the major work of hypersonic waveriders is done, we do not single out individuals as being the waverider person. We have many major contributors, but only as a research group, under the direction of Drs. John D. Anderson, Jr and Mark J. Lewis have we established the validity of the waverider. Waverider research basically began here in 1986 with Kevin Bowcutt and has continued since. With the arrival of Mark Lewis in 1987 we now have two major contributors to the field. > >I'd have to say that the papers in the session I saw might not be real >accessible to the lay person, but I may be underestimating that person. See comments above. - ------------------------------------------------------ Charles Lind -- lind@eng.umd.edu Hypersonics Research Group Department of Aerospace Engineering University of MD, College Park, MD 20742 - ------------------------------------------------------ ------------------------------ From: gt6745b@prism.gatech.edu Date: Mon, 18 Jan 93 13:14:38 EST Subject: AW&ST Can anyone out there provide me with the address for "Aviation Week and Space Technology"? I'd certainly like to start getting it. Thanks. -Michael Michael David Knight gt6745b@prism.gatech.edu * COMBAT AIRCRAFT: A mix of * Georgia Institute of Technology * sharp teeth, cold steel, * Atlanta, Georgia 30332 * cosmic warlords, and evil * Aerospace Engineering (404)676-0520 * spirits. * ------------------------------ From: "Philip R. Moyer" Date: Mon, 18 Jan 1993 13:25:22 EST Subject: Re: AW&ST >Can anyone out there provide me with the address for "Aviation Week and >Space Technology"? I'd certainly like to start getting it. Thanks. Sure. According to the January 11 issue, the address is Aviation Week and Space Technology P.O. Box 503 Hightstown, NJ 08520-9899 The subscription card in this issue lists the rates as 1 year $ 82.00 2 years $150.00 3 years $220.00 Worth every penny, in my opinion. Philip R. Moyer ECN Software Staff Engineering Computer Network Voice: 317-494-3648 prm@ecn.purdue.edu Fax: 317-494-6440 ------------------------------ From: dnadams@nyx.cs.du.edu (Dean Adams) Date: Mon, 18 Jan 93 20:50:03 MST Subject: B2 note B-2 CLEARS HURDLES: WASHINGTON (AFNS) -- The Air Force has selected an approach to deal with the B-2 signature anomaly that was discovered in the flight test program in July 1991, the secretary of the Air Force announced Jan. 14. Donald B. Rice told reporters at the Pentagon that "Option2," known as the "Improved Treatments" option, has been selected because it meets operational requirements, is the lowest technical risk and is the least costly. The other two options did not offer a significant increase in aircraft survivability and are more costly, Rice said. In August 1992, the Air Force was considering three options to reach the B-2's signature goals. In test conducted early in 1991, the B-2 produced an anomaly in one area of its signature. A special, independent Blue Ribbon team of technical experts determined that the B-2 design was sound, and that the signature variance was not produced by the B-2's basic design. When this variance occurred, the Air Force consulted with Congress and put together a special effort to find a sound technical solution. As part of this effort, the B-2 low observables closure team developed what Rice described as a "national treasure," new and unique diagnostic capabilities for the B-2 and any future low observable program. These diagnostic tools enabled the team to precisely measure and fine- tune stealth technology by detecting "hot spots" on the aircraft, just as forward-looking infrared imagery detects thermal hot spots, Air Force officials said. The ensuing test also allowed B-2 engineers to identify a solution to the B-2 signature anomaly that meets Air Combat Command's requirements at the least cost. Rice said the results of the testing confirmed the Air Force's expectations of a highly survivable aircraft. Used primarily in a conventional role, the B-2 will be the "point of the spear," penetrating the most heavily defended areas on day one of a conflict with its precision guided munitions, flying from bases in the continental United States if need be, officials said. The assessment culminated more than a year's worth of low observable activity by the Air Force to correct the discrepancy identified to Congress in 1991. ------------------------------ From: dnadams@nyx.cs.du.edu (Dean Adams) Date: Tue, 19 Jan 93 00:48:39 MST Subject: Blackbird notes Here are a few Blackbird-related items of interest... SR-71 Mach/altitude Growth: The aircraft was designed for extended cruise flight at Mach 3.2. Various studies have been conducted regarding extending the speed of the SR-71 beyond 3.2. The results of these studies conclude that extension to Mach 3.5, for short periods of time (of 10 minutes or more), is feasible, with approach to that speed to be accomplished incrementally. Extension above Mach 3.5 will be more involved and difficult, requiring substantially greater effort. Mach extension to 3.4 can be achieved without any significant flight test program or change to the aircraft. Extension from 3.4 to 3.5 may require the addition of instrumentation; insulation of inlet hydraulic lines and, possibly, inlet actuators; and a flight test program, which is planned. One of the studies conducted regarding Mach 3.5 flight also addressed achiving higher altutide flight. The study indicated that the aircraft could be zoomed to an altitude of about 95,000 feet. This would be accomplished with an aircraft gross weight of about 85,000 pounds. The aircraft would be accelerated from Mach 3.2 to Mach 3.5, at an altitude of 80,000 feet, then zoomed to 95,000 feet, with Mach decaying back to approximately 3.2. The aircraft would subsequently settle back to an altutide of about 84,000 feet. -- The SR-71 was intended for maximum range flight at altitudes of or approaching 85,000 feet, with speeds at or approaching Mach 3.2. During its military career, the SR-71 rarely and only slightly exceeded its design speed and altitude limits. Studies have been made to determine of these limits could be extended. Study results show that a Mach number of 3.5 is readily attainable, with sufficient thrust at that speed to carry a large external payload. The only structural limitation related to speed above 3.5 is a KEAS limit of 420, set by inlet duct pressures and temperatures which exceed acceptable values. Other factors which limit speed above Mach 3.5 are inlet capture area and excessive engine compressor inlet temperature (CIT). Factors which limit sustained flight at altitudes above 85,000 feet are wing area and/or propulsion system thrust. Replacement of existing outboard wing panels with larger ones will provide increased wing surface area. Increased thrust will require installation of a new powerplant and inlet design. - -=-=- D-21 Drone: The D-21 was designed as a high-altitude reconnaissance drone to be launched from a modified A-12 aircraft, designated M (mother) -12. The D (daughter) -21 has a delta wing, an internally-mounted ramjet engine, and uses 5900 pounds of JP-7 fuel, the same fuel as used by the SR-71. Construction is of titanium and the inlet consists of a fixed spike and air bypass. The drone is over 42 feet long, has a wing span of over 19 feet, and a total (fueled) weight of 11,200 pounds. The D-21 was pylon-mounted on the aft fuselage of the M-12. It was launched at altitudes of about 85,000 feet, at speeds of about Mach 3.2. This speed/altitude was required to minimize lift loads and drag on the vehicle and to "start" the drone engine. The D-21 cruises above Mach 3.2 and has a considerable range. Operational mission applications are still classified. Approximately 17 D-21s are stored for possible reuse at Davis-Monthan AFB in Arizona. - -=-=- NASA Drone: NASA requested a study to investigate mounting a hypersonic drone on a YF-12 aircraft for a launch at cruise altitude and Mach. For the study, a NASA HT-4 drone was to be scaled for a fuselage length of 50 feet, with a total (fueled) weight of 14,800 pounds. The drone was enlarged to accommodate a Pratt and Whitney RL-10 liquid rocket engine and a 115-inch tail cone fairing was added to decrease drag during mated flight. A canoe, with a 5 by 7 inch cross-section, was added along the bottom centerline of the drone to accommodate launch attachments and landing provisions. Various mounting provisions, locations, and methods of launch were investigated. In its final configuration, the mounting consisted of a single, thin pylon, with a length approximately that of the drone, located on the top centerline of the aft fuselage of the aircraft. This location required blocking the wing sections of the aircraft aft fuel tanks (to maintain c.g. during mated flight) and modifications of the aircraft fuel system to forward transfer fuel when the drone was elevated for launch (to compensate for aft movement of combined drone/aircraft c.g.) Although this location required modification of the aircraft fuel system it provided clearance for crew ejection and minimized drone engine plume impingement on the aircraft. After considering other methods (flyaway and impulse), aerodynamic lift was selected as the most appropriate means of drone separation from the aircraft. The drone was stowed at a low angle of attack (low drag) position until just before launch. At launch, a launch beam was raised from horizontal to a vertical position, elevating the drone 8 degrees in pitch and moving it somewhat aft on rollers. The elevated position of the drone gave it positive lift of at least twice its weight, imposing on it a vertical acceleration away from the aircraft of at least 1 G. The acceleration of the drone could be modified by application of aircraft elevon control. The study concluded that installation and launch of the specified drone was feasible. - -=-=- GAR-9 Missile: The GAR-9 missile was essentially a large scale AIM-4 (Phoenix type) missile, with a weight of 815 pounds, a length of over 12-1/2 feet, a diameter of 13-1/2 inches, and a span of 33 inches. The missiles, mounted on launchers, one to a bay, were carried in three internal bays in the YF-12A aircraft. During launch, the missiles were ejected downward by pyrotechnic charges. There were seven supersonic launches of the missile at aircraft speeds from Mach 2.19 to 3.2, at altitudes of 65,000 to 76,000 feet. - -dean ------------------------------ End of Skunk Works Digest V2 #56 ******************************** To subscribe to skunk-works-digest, send the command: subscribe skunk-works-digest in the body of a message to "listserv@harbor.ecn.purdue.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@harbor.ecn.purdue.edu" or, if you don't like to type a lot, "prm@ecn.purdue.edu". 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