From: skunk-works-digest-owner@harbor.ecn.purdue.edu To: skunk-works-digest@harbor.ecn.purdue.edu Subject: Skunk Works Digest V3 #71 Reply-To: skunk-works-digest@harbor.ecn.purdue.edu Errors-To: skunk-works-digest-owner@harbor.ecn.purdue.edu Precedence: bulk Skunk Works Digest Saturday, 3 July 1993 Volume 03 : Number 071 In this issue: crowbars and crosshairs Al White and XB70 Re: crowbars and crosshairs Re: crowbars and crosshairs SWERVE Paris Air Show Re: SWERVE Paris Air Show Re: SWERVE Vindication Re: SWERVE 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: Rick Pavek Date: Fri, 2 Jul 1993 00:36:10 -0700 Subject: crowbars and crosshairs why does it have to tumble? Small fins could keep in aligned with the trajectory. Coat it with an adequate layer of Shuttle ceramic. In fact, it would have to be a straight flyer since it's steerable. Shape it like the type of pin with the small ball on the end. Put the seeker on the front. The 'ball' on the end could be sectioned in quarters, extend a quarter into the slipstream to steer it (like the exhaust petals on the F105 Thud - the airbrakes). Better yet, drop a pod with a cluster of them from orbit and slow them down... no, just protect them long enough to get into the atmosphere and acquire the target. Yeah (make up your mind, Rick!), you'd slow them down some. But you could do this from 80K feet just as easy and cheaper, too. Why the pin shape? Well, it works. I used them in a straw to make a crude blowgun. Stuck them into the wall (I was _very_ bored that afternoon... ;-) Rick ------------------------------ From: S.Dray@ste0402.wins.icl.co.uk Date: Fri, 2 Jul 1993 08:59:23 +0100 Subject: Al White and XB70 Sometime ago I wrote asking for information on an XB70 pilot who escaped the crash his Name was AL WHITE can anyone tell me anything about him. He also flew as an X project pilot with Chuck Yeager. I was given duff gen the last time round as Ed White was killed in the Apollo Fire. (Gravity is a Myth the Earth Sucks ) ------------------------------ From: "Philip R. Moyer" Date: Fri, 02 Jul 1993 08:34:31 EST Subject: Re: crowbars and crosshairs >why does it have to tumble? Small fins could keep in aligned with the >trajectory. Coat it with an adequate layer of Shuttle ceramic. > >In fact, it would have to be a straight flyer since it's steerable. > >Shape it like the type of pin with the small ball on the end. Put the >seeker on the front. The 'ball' on the end could be sectioned in >quarters, extend a quarter into the slipstream to steer it (like the >exhaust petals on the F105 Thud - the airbrakes). The Air Force Museum in Dayton, Ohio, has one of the (used) SWERVE proof of concept vehicles. I don't have all the info here, so this is from memory; perhaps one of the lucky individuals who lives in Dayton could bop over on their lunch break and check it out (it's right near the Apollo capsule, along the same wall), then report the exact info back to the list. It's 3.5 or 4 meters long, and at its largest cross section, is about 30 or 40 centemeters in diameter. It looks, not surprisingly, like a very elongated high-accuracy boattail rifle bullet. It is a sharply pointed cone with a boattail. The surface is black, and rough to the touch, almost like not-quite- finished fiberglass, though it's obviously not. The procedure for this vehicle was to mount it on a solid rocket booster, which was then mounted atop an Atlas rocket. The Atlas took the package up over the Pacific test range, then it nosed over and the solid rocket fired, accelerating it downwards. I think the SR separated at something like 180,000 feet, and it controlled itself all the way down. There are small, long panels near the base, which are hinged along the leading edge. These panels are almost rectangular, except they are narrower at the leading edge than the trailing edge. There are small hydraulic arms under the panels which lift them up. This changes the aerodynamics of the vehicle and provides for steering. If I remember correctly, it was controllable at Mach 14 and had a "range", in which it could be steered, of 7000 nm. Hmmm. That might've been 700 nm. I'll have to drive to Dayton to check.... ;-) Cheers, Phil ------------------------------ From: Mary Shafer Date: Fri, 2 Jul 1993 13:23:11 -0400 (EDT) Subject: Re: crowbars and crosshairs Here's a section from AIAA-93-0311, "A Comparison of Hypersonic Flight and Prediction Results" by Iliff and Shafer. Actually, this is a section from the draft, as I don't have a copy of the final text since I turned it over to my editor at this poing. \section{SWERVE Flight Test Experience} Sandia designed, developed, and conducted three flight tests of a slender hypersonic vehicle called SWERVE (Sandia Winged Energetic Reentry Vehicle Experiment) (Ref.\ \cite{williamson}). The first flight test occurred in 1979 and the last in 1985. All vehicles flown were spherically blunted conical vehicles. The cone half-angle in all cases was $5.25^\circ$ and the third vehicle was a little over 100 inches long. The nose tip radius to base radius ratio was about 0.07. Small wings and elevons were used to increase lift and provide control. The heat shield and nosetip were ablative materials. The vehicle was flown out of the Kauai Test Facility and, in the case of the third flight, reentered near Johnston Island. A large wind tunnel database exists on this shape. Figure \ref{walt1} shows the extent of the database for the Reynolds number based on vehicle length as a function of Mach number. Some of the flight test experience from this flight, relating to aerodynamics and aerothermodynamics, is summarized in the following paragraphs. A complete simulation of aerodynamics, aerothermodynamics, dynamics, trajectories, and autopilot were done preflight. \begin{figure}[p] \vspace{1.0cm} \caption{\label{walt1} Wind tunnel test conditions for the SWERVE vehicle.} \end{figure} The SWERVE maneuver from the third flight (shown in Fig.\ \ref{walt2}) included a $-10^\circ$ angle of attack Mach 12 high altitude pull out at 20 seconds, requiring control deflections of $4^\circ$, followed by a return to $0^\circ$ angle of attack at 60 sec at about Mach 8. Preflight it was assumed the boundary layer would be laminar at Mach 14 and turbulent at Mach 8, so the boundary layer was artificially tripped in the Mach 8 wind tunnel studies to ensure a turbulent boundary layer. A comparison of the response predicted by the wind tunnel at Mach 14 and 8 are compared to the flight data in Figs.\ \ref{walt3} and \ref{walt4} respectively. Note that the Mach 14 wind tunnel data accurately predict the control deflection observed in flight at Mach 8 and the Mach 8 wind tunnel data match the control deflection from flight at Mach 12. Surprisingly, the flight data exhibited a turbulent boundary layer at Mach 12 and a laminar boundary layer at Mach 8, which accounted for some of the peculiar agreement between the flight and wind tunnel predictions. In addition, there was disagreement preflight as to which wind tunnel and limited computational fluid dynamics (CFD) predictions would more accurately predict the flight results. Recently, a parabolized Navier-Stokes (PNS) code has been used to predict the control surface deflection, $\delta$. This PNS code accurately matches the Mach 14 laminar and Mach 8 turbulent wind tunnel data. The PNS, which used values that match the boundary layer states observed in flight, are shown in Tables \ref{waltt1} and \ref{waltt2} (Mach 12 turbulent and Mach 8 laminar). The PNS results accurately predict the control deflection for Mach 12 (turbulent) but are not as close for Mach 8 (laminar). A 20--30\% difference still exists. The PNS prediction, which is a function of the Reynolds number and boundary layer state, is still incorrect in some places. The wind tunnel prediction and CFD results still do not agree well with flight in some areas. \begin{figure}[p] \vspace{1.0cm} \caption{\label{walt2} Angle of attack and control deflection time histories for the SWERVE vehicle.} \end{figure} \begin{figure}[p] \vspace{1.0cm} \caption{\label{walt3} Comparison of flight measured control deflection with Mach 14 wind tunnel prediction.} \end{figure} \begin{figure}[p] \vspace{1.0cm} \caption{\label{walt4} Comparison of flight measured control deflection with Mach 8 wind tunnel prediction.} \end{figure} \begin{table}[p] \begin{center} \begin{tabular} {ccccc}\hline \multicolumn{5}{l}{PNS results (Mach 12)} \\ \hline \hline $\alpha$ & $\delta$ & $C_N$ & $X_{\mbox{CP}}/\mbox{LB}$ & $C_m$ \\ deg & deg & & & \\ \hline 10 & 0 & 0.476 & 0.701 & -0.00529 \\ \hline 10 & 5 & 0.452 & 0.687 & 0.00114 \\ \hline 10 & 10 & 0.437 & 0.6878 & 0.00514 \\ \hline \multicolumn{3}{l}{$M=12$} & \multicolumn{2}{l}{$\delta_{\mbox{TRIM}} = 4.11^\circ$} \\ \multicolumn{3}{l}{Turbulent} & \multicolumn{2}{l}{$T_W = 4000^\circ R$} \\ \end{tabular} \end{center} \caption{\label{waltt1} PNS Results for Mach 12 with turbulent boundary layer.} \end{table} \begin{table}[p] \begin{center} \begin{tabular} {ccccc}\hline \multicolumn{5}{l}{PNS results (Mach 8)} \\ \hline \hline $\alpha$ & $\delta$ & $C_N$ & $X_{\mbox{CP}}/\mbox{LB}$ & $C_m$ \\ deg & deg & & & \\ \hline 2 & 0 & 0.0930 & 0.721 & -0.00291 \\ \hline 2 & 2 & 0.0861 & 0.702 & -0.00107 \\ \hline 2 & 5 & 0.0756 & 0.667 & 0.00175 \\ \hline \multicolumn{3}{l}{$M=8$} & \multicolumn{2}{l}{$\delta_{\mbox{TRIM}} = 3.1^\circ$} \\ \multicolumn{3}{l}{Laminar} & \multicolumn{2}{l}{$T_W = 2000^\circ R$} \\ \end{tabular} \end{center} \caption{\label{waltt2} PNS Results for Mach 8 with laminar boundary layer.} \end{table} Boundary layer transition was determined postflight from a combination of thermocouple data and photodiode data. Flight measured temperature at about the midpoint of the cone are shown in Fig.\ \ref{walt5}, with preflight predictions with the General Electric low mass addition (GELMA) criteria and with CFD results assuming the entire flight is laminar. The oscillation at the end of the time history were due to changes in the angle of sideslip. Figure \ref{walt6} shows photodiode data on opposite sides of the cone at the 89 in.\ station which indicates that when the attitude of the vehicle was changed the windwardside flow ($180^\circ$ ray) went from laminar to turbulent (full-scale or 100 unit photodiode indication) and the leeward side flow ($0^\circ$ ray) went from turbulent to laminar. Utilizing the boundary layer state observed in flight (such as that for the photodiode data shown in Fig.\ \ref{walt6}) resulted in the flight-corrected CFD curve shown in Fig.\ \ref{walt5}. It matches the flight data very well. There were over one hundred thermocouples located throughout the vehicle thermal protection system and agreement between flight and prediction was very good once the boundary layer state pattern observed in flight was used in conjunction with the prediction. Figure \ref{walt7} shows the GELMA criteria and the state of the boundary layer observed in flight. The criteria clearly is not adequate for this flight. \begin{figure}[p] \vspace{1.0cm} \caption{\label{walt5} Comparison of flight measured temperature on the cone with predicted temperature for several different criteria.} \end{figure} \begin{figure}[p] \vspace{1.0cm} \caption{\label{walt6} Photodiode data at 89 in.\ station for the $180^\circ$ and the $0^\circ$ rays.} \end{figure} \begin{figure}[p] \vspace{1.0cm} \caption{\label{walt7} Comparison of flight data with boundary layer state and prediction criteria.} \end{figure} In summary, the SWERVE vehicle has been flight tested three times. The data discussed in this paper is from the third flight. A very large wind tunnel database exists with sophisticated CFD codes to predict flight conditions. Some uncertainty still exists in the aerodynamic database and large uncertainty exists in the prediction of boundary layer state, as shown in the differences between the predicted values and the flight values. The boundary layer state affects the aerodynamic state and has a major impact on the aerothermodynamics, affecting the adequacy of the thermal protection systems. Mary Shafer DoD #0362 KotFR shafer@ursa-major.spdcc.com ------------------------------ From: larry@ichips.intel.com Date: Fri, 2 Jul 1993 13:37:59 -0700 Subject: SWERVE Phil writes: >The Air Force Museum in Dayton, Ohio, has one of the (used) SWERVE proof >of concept vehicles. This is amazing! When the articles on SWERVE were written in 1990, the shape was still classified, "because of what it resembled" according to one source I personally talked to. That's great if it actually available now for inspection! I'd love to see it! Larry ------------------------------ From: "Philip R. Moyer" Date: Fri, 02 Jul 1993 17:01:23 EST Subject: Paris Air Show Hughes Aircraft was warned by the CIA on (or near) April 16 that the French government had a series of industrial espionage operations planned against US firms participating at the Paris Air Show. Based on that warning, Hughes cancelled its plans to go to the show. Other firms targetted were IBM, McDonnell Douglass, Boeing, General Dynamics, and, of course, Lockheed. Does anyone know whether or not these firms actually participated in the show? Cheers, Phil ------------------------------ From: Mary Shafer Date: Fri, 2 Jul 1993 18:06:05 -0400 (EDT) Subject: Re: SWERVE You'll notice that our paper didn't have any figure showing the vehicle, although there is a pretty good description. I don't remember why this happened. It may have been that no good figure was readily available. I know that I have seen photos and/or drawings. Mary Shafer DoD #0362 KotFR shafer@ursa-major.spdcc.com On Fri, 2 Jul 1993 larry@ichips.intel.com wrote: > > > Phil writes: > >The Air Force Museum in Dayton, Ohio, has one of the (used) SWERVE proof > >of concept vehicles. > > This is amazing! > > When the articles on SWERVE were written in 1990, the shape was still > classified, "because of what it resembled" according to one source I > personally talked to. > > That's great if it actually available now for inspection! > > I'd love to see it! > > Larry ------------------------------ From: "Philip R. Moyer" Date: Fri, 02 Jul 1993 17:01:23 EST Subject: Paris Air Show Hughes Aircraft was warned by the CIA on (or near) April 16 that the French government had a series of industrial espionage operations planned against US firms participating at the Paris Air Show. Based on that warning, Hughes cancelled its plans to go to the show. Other firms targetted were IBM, McDonnell Douglass, Boeing, General Dynamics, and, of course, Lockheed. Does anyone know whether or not these firms actually participated in the show? Cheers, Phil ------------------------------ From: Mary Shafer Date: Fri, 2 Jul 1993 18:06:05 -0400 (EDT) Subject: Re: SWERVE You'll notice that our paper didn't have any figure showing the vehicle, although there is a pretty good description. I don't remember why this happened. It may have been that no good figure was readily available. I know that I have seen photos and/or drawings. Mary Shafer DoD #0362 KotFR shafer@ursa-major.spdcc.com On Fri, 2 Jul 1993 larry@ichips.intel.com wrote: > > > Phil writes: > >The Air Force Museum in Dayton, Ohio, has one of the (used) SWERVE proof > >of concept vehicles. > > This is amazing! > > When the articles on SWERVE were written in 1990, the shape was still > classified, "because of what it resembled" according to one source I > personally talked to. > > That's great if it actually available now for inspection! > > I'd love to see it! > > Larry ------------------------------ From: Rick Pavek Date: Fri, 2 Jul 1993 21:18:29 -0700 Subject: Vindication Ah... feels so good. The SWERVE now sounds exactly like what I'm calling the crowbar. In the original work (It might have been either _High Frontier_ or _Mutual Assured Survival_ by Jerry Pournelle) the crowbar was simply a metaphor that described an inert, steerable projectile that could hunt down a tank. It didn't necessarily have to -look- like a crowbar. It'll be interesting to see what else comes out of the SWERVE... Rick ------------------------------ From: dnadams@nyx.cs.du.edu (Dean Adams) Date: Fri, 2 Jul 93 22:54:46 MDT Subject: Re: SWERVE Phil said: > ...I think the SR separated at something like 180,000 feet, and it > controlled itself all the way down. There are small, long panels near the >base, which are hinged along the leading edge. These panels are almost >rectangular, except they are narrower at the leading edge than the trailing >edge. There are small hydraulic arms under the panels which lift them up. >This changes the aerodynamics of the vehicle and provides for steering. Interesting... The DC-X has the very same sort of "petals" as control surfaces. Sounds like it may owe a lot to past SWERVE research. - -dean ------------------------------ End of Skunk Works Digest V3 #71 ******************************** 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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