From: owner-skunk-works-digest@netwrx1.com (skunk-works-digest) To: skunk-works-digest@netwrx1.com Subject: skunk-works-digest V8 #74 Reply-To: skunk-works@netwrx1.com Sender: owner-skunk-works-digest@netwrx1.com Errors-To: owner-skunk-works-digest@netwrx1.com Precedence: bulk skunk-works-digest Sunday, June 27 1999 Volume 08 : Number 074 Index of this digest by subject: *************************************************** Re: ATF testing Re: ATF testing Re: ATF testing Re: ATF testing Re: ATF testing Re: ATF testing Re: ATF testing Re: ATF testing/C-130 specs Re: ATF testing/C-130 specs Thrust vectoring Re: ATF testing *************************************************** ---------------------------------------------------------------------- Date: Fri, 25 Jun 1999 20:44:14 -0400 From: "James P. Stevenson" Subject: Re: ATF testing > James P. Stevenson wrote besides other things: > >>Life is a trade-off. The question on the table is whether the F-22 would >>be more maneuverable with the loss of the added weight due to the thrust >>vectoring mechanism. > >>In the mid-1970s, Topgun did some experiments on thrust vectoring. It >>took two F-11s (F11Fs), one with thrust vectoring and one without. It >>put them on the ACMI range and ran the tests. I watched them. The thrust >>vectoring was impressive. However, the F-11 without the thrust vectoring >>prevailed. > >>The consensus was that the added weight degraded performance enough that >>it subtracted from whatever advantage the thrust vectoring added. > >>When you learn how much the mechanism weighs that holds the thrust >>vectoring apparatus on the F-22, plus the vectoring mechanism itself, >>you will probably conclude that Topgun had it right. > > That was in the early 1970s, over 25 years ago, and it wasn't really a > thrust vectoring system, but more an "inflight thrust-reverser". And what > about the F/A-18A HARV, X-31As, and other thrust vectoring aircraft tests > since then? The Russians (despite all their other problems and shortcomings) > seem to value thrust vectoring engines on some of their aircraft (including > the Su-30MK/MKI). > > OTOH, the same (added/increased weight and complexity for the purpose of > gaining additional capabilities) can be said for many things in fighter > aircraft design, but is of course especially true for variable geometry > (swing wings), which faded away after the 1970s/1980s. Thrust vectoring > might become as out-moded as variable geometry, while stealth might become > as prevasive as the jet-engine. Only time will tell. > > -- Andreas > I agree. Jim Stevenson > ------------------------------ Date: Fri, 25 Jun 1999 20:49:27 -0400 From: "James P. Stevenson" Subject: Re: ATF testing > james p. stevenson wrote: < To which Wayne Binkley replied: > i > suspect this conversation is about fighter acft,but i must take up the > "ever"challenge.in 1951 the a.f.wanted a cargo plane that could carry 90 > troops,slow to 125kts for airdrops,land on un improved rough fields and > carry 30,000lbs in 2,000 mile increments.the yc130A flew in 1953,af started > taking delivery in 1955.they are still taking delivery of the 1999 C-130J. Wayne may have touched upon an airplane that met its original spec. (I'm sure glad he didn't bring up the C-17.) In any event, Wayne, you did not say that the airplane did meet it; only that you thought it did. Let's find out. Jim ------------------------------ Date: Fri, 25 Jun 1999 20:50:42 -0400 From: "James P. Stevenson" Subject: Re: ATF testing > James P. Stevenson spewed forth the following: > >>You are so right. The question is: should we hold military program >>managers to the same standard that the law hold the average citizen to? >>In other words, does fraud in the inducement apply to the military? >> >>I maintain that it should. If you have a house built and the builder >>tells you it will cost $200,000; you make plans on that basis; you >>budget your household to that amount; you procure a loan based on that >>amount; and on settlement day he tells you ill will be $479,500, you >>will proabably cry foul. >> > > Houses are not new technology, new technology is hard to quote, since its > in a development process. > I am suggesting that we set a figure and get the best we can for it; not set an elusive goal, spend and spend, and never meet it. Jim Stevenson ------------------------------ Date: Fri, 25 Jun 1999 20:52:01 -0400 From: "James P. Stevenson" Subject: Re: ATF testing > You spewed forth the following: > >>>> Experiments were done at Topgun in the mid-1970s on thrust vectoring. >>>> Using two F11Fs (F-11s). The added weight of the thrust vectoring >>>> mechanism offset any advantage. >>> >>> Don't you thing that thrust vectoring technology have improve >>> since mid-1970s? New material, less complexity, etc. >> >>Yes. But the weight has increased as well so the problem is the same or >>worse. >> > > What about the ACTIVE and VISTA F-15 and F-16, they used an almost stock > F100 nozzle, with 3-D vectoring? I am not familiar with them. Were there trade-off flight test done with them? Jim Stevenson ------------------------------ Date: Fri, 25 Jun 1999 20:55:45 -0400 From: "James P. Stevenson" Subject: Re: ATF testing > James P. Stevenson wrote: > >> >> The "original spec" is not an absolute truth. >> > >> You are so right. The question is: should we hold military program >> managers to the same standard that the law hold the average citizen to? >> In other words, does fraud in the inducement apply to the military? >> >> I maintain that it should. If you have a house built and the builder >> tells you it will cost $200,000; you make plans on that basis; you >> budget your household to that amount; you procure a loan based on that >> amount; and on settlement day he tells you ill will be $479,500, you >> will proabably cry foul. >> >> It makes precious little difference if you are told along the way, >> either. Overrun is overrun. But hey, its other people's money so they >> don't care. Well, its my money, and I do care. > > Was it a cost plus fixed fee or firm fixed price contract? If it was > FFP then you plunk down your $200K and you're done. The contractor > ponies up the rest. If it was cost plus, contract law will require you > to pay the full amount because you were the one to benefit from the > work. Both of these situations apply outside of the military contracts > process. As a contractor, if you really want a fixed price contract for > something no one has ever done before I will jack up the cost to try to > cover the uncertainties - or not bid at all. Not to exceed CPFF > contracts are used to try to keep the cost to the customer down. Now, > which way is really in the best interests of the taxpayer? > > >> > >> >> There is usually alot of >> >> uncertainty in what is attainable or affordable for an R&D effort when >> >> the detailed design, fabrication, & test work hasn't been done yet. >> > >> Fine. Then we should decide what amount of money we are willing to pay >> for uncertainly, and ask the military to give us the best they can for >> that amount. In other words, give me the best airplane that $X billion >> will buy. >> > > > Many cost overruns have been caused by the customer changing their mind > about what they really want. Architects see it all the time. I'm not > in business to provide charity to the government. > >> >> Don't you want to set ambitious goals? >> > >> Yes, but I don't want to pay for expanding goals. >> > > That's completely up to the customer. > >> > >The specs can also be set too >> >> high due to flawed or unsophisticated analysis early in a program which >> >> will end up being corrected later on as more is known about the system. >> > >> You want goals: how about this one--here is X dollars. Do the best you >> can. >> > > > But that means you can't tell me how to do it, too. One place military > money gets spent is tracking government property down to individual 1/8" > washer. DOD regulations require that I track ALL items of ANY value > that I buy on a CPFF contract, resulting in many cases in tracking > paperwork costs far exceeding the value of the items. I would speculate > that overall the costs associated with property tracking far exceed the > losses due to fraud - the reason property tracking of ALL items was > instituted in the first place. > > So how do you decide how big X is? Ask the people who build these types > of things how much it will cost? If you set a FFP program cost too low > you will either get no bidders or unqualified bidders who will then > spend all the money and go bankrupt, leaving you with no aircraft and no > money too. Is this really what you want? > >> > >> Architects build to a cost goal. >> > >> >>The specs are USUALLY >> >> moving targets, with extra capabilities and performance goals added on >> >> AFTER the conceptual design work has been done and the contracts >> >> signed. >> > >> You are so right about part of your statement and wrong about the other >> part. The moving target is the downward spiral of the specification. >> Performance seldom increases and the performance goals you speak of are >> reductions in goals. But you are correct when you say it all happens >> after the contract is signed. The next thing that happens is a breach of >> the cotract. >> > >> >>If the government was just asking for off-the-shelf hardware >> >> already in production the spec would be the capability of the equipment >> >> they planned to buy in the first place - there's no uncertainty there, >> >> so is the spec setting the performance or the performance setting the >> >> spec in this case? Once production has started the specifications >> >> should be reasonable and well-understood and serve as a basis to accept >> >> or reject delivery. >> > >> I have no objection to R&D. I just want an agreement on how much we are >> going to spend in advance, not how much we can run up the bill to >> attempt to reach a goal that history tells us the military seldom meets. >> > > By definition, if it is research we don't know the answer. Research is > also, to a large extent, composed of efforts that don't turn out the way > we would like them to. > I can't disagree with what you've said. The point I am attempting to make is that concepts are sold as a "must have" or the Russians are coming. When we don't come close to the "must have" we get, "Oh, no problem. This is fine." R&D costs money. All I want is honesty in the process. Jim Stevenson ------------------------------ Date: Fri, 25 Jun 1999 21:44:39 -0400 From: Gunman and Jacks Subject: Re: ATF testing You spewed forth the following: >> What about the ACTIVE and VISTA F-15 and F-16, they used an almost stock >> F100 nozzle, with 3-D vectoring? > >I am not familiar with them. Were there trade-off flight test done with >them? > Here are a couple links: F-15 ACTIVE homepage: http://www.dfrc.nasa.gov/Projects/active/ F-16 VISTA http://home.sprintmail.com/~mvdunbar/Aircraft/ap_matv.html - ---------------------------------------- Gunman and Jacks PGP Key Available - ----------------------------------------- ------------------------------ Date: Sat, 26 Jun 1999 06:03:34 -0400 From: "James P. Stevenson" Subject: Re: ATF testing > You spewed forth the following: > >>> What about the ACTIVE and VISTA F-15 and F-16, they used an almost stock >>> F100 nozzle, with 3-D vectoring? >> >>I am not familiar with them. Were there trade-off flight test done with >>them? >> > > Here are a couple links: > > F-15 ACTIVE homepage: > http://www.dfrc.nasa.gov/Projects/active/ > > F-16 VISTA > http://home.sprintmail.com/~mvdunbar/Aircraft/ap_matv.html > I reviewed the pages. Other than the F-16 Vista having a close in combat advantage, it did not make other necessary comparisons, such as the relative cost, what the advantages not close in, etc. Jim Stevenson ------------------------------ Date: Sat, 26 Jun 1999 14:27:20 PDT From: wayne binkley Subject: Re: ATF testing/C-130 specs >From: "James P. Stevenson" >Reply-To: skunk-works@netwrx1.com >To: skunk-works@netwrx1.com >Subject: Re: ATF testing >Date: Fri, 25 Jun 1999 20:49:27 -0400 > > > james p. stevenson wrote: > < > > >To which Wayne Binkley replied: > > > i > > suspect this conversation is about fighter acft,but i must take up the > > "ever"challenge.in 1951 the a.f.wanted a cargo plane that could carry 90 > > troops,slow to 125kts for airdrops,land on un improved rough fields and > > carry 30,000lbs in 2,000 mile increments.the yc130A flew in 1953,af >started > > taking delivery in 1955.they are still taking delivery of the 1999 >C-130J. > > >Wayne may have touched upon an airplane that met its original spec. (I'm >sure glad he didn't bring up the C-17.) In any event, Wayne, you did not >say that the airplane did meet it; only that you thought it did. Let's >find out. > >Jim > jim, there are several books out about the C-130,however i can tell you this much off the top of my head with out using a book for reference.(i have 5,800 hrs flying time in C-130B-,C-130E,C-130H .all cargo versions of the C-130,starting with the"A"mod can carry 92 troops,slow down to 125kts for airdrop(even slower for a max effort assault landing).they can take off and land on short,unimproved runways(3500ft).the "A"model had a maximum take off weight of 124,200 lbs. in 1958 we got the "B" model 135,000 lbs.(155,000 lbsEWP,-emergency war plans.the "B"was quickly followed by the"E"which had a normal max take off weight of 155,000 lbs(175,000lbs-EWP). next came the "H" model,basically an"E" with more powerful engines.later models were called"H2"and"H3". the model now in production(C-130J)looks the same,but has a six blade dowtey(sic?)composite prop,new more powerful engines,all new "glass"cockpit,etc.lockheed AND the airforce say it is about 70% different from older model C-130s.the"J"just broke or set about 50 world records for turboprop acft in several weight classes.a representative of the international agency(i forget the name, believe the initials are the FAI)was on board to certify these records,so it was not just lockheed propaganda. wayne d.binkley _______________________________________________________________ Get Free Email and Do More On The Web. Visit http://www.msn.com ------------------------------ Date: Sat, 26 Jun 1999 18:38:51 -0400 From: "James P. Stevenson" Subject: Re: ATF testing/C-130 specs I wrote: >>Wayne may have touched upon an airplane that met its original spec. (I'm >>sure glad he didn't bring up the C-17.) In any event, Wayne, you did not >>say that the airplane did meet it; only that you thought it did. Let's >>find out. >> >>Jim Wayne replied: >> > jim, there are several books out about the C-130,however i can tell you this > much off the top of my head with out using a book for reference.(i have > 5,800 hrs flying time in C-130B-,C-130E,C-130H .all cargo versions of the > C-130,starting with the"A"mod can carry 92 troops,slow down to 125kts for > airdrop(even slower for a max effort assault landing).they can take off and > land on short,unimproved runways(3500ft).the "A"model had a maximum take off > weight of 124,200 lbs. in 1958 we got the "B" model 135,000 lbs.(155,000 > lbsEWP,-emergency war plans.the "B"was quickly followed by the"E"which had a > normal max take off weight of 155,000 lbs(175,000lbs-EWP). next came the "H" > model,basically an"E" with more powerful engines.later models were > called"H2"and"H3". the model now in production(C-130J)looks the same,but has > a six blade dowtey(sic?)composite prop,new more powerful engines,all new > "glass"cockpit,etc.lockheed AND the airforce say it is about 70% different > from older model C-130s.the"J"just broke or set about 50 world records for > turboprop acft in several weight classes.a representative of the > international agency(i forget the name, believe the initials are the FAI)was > on board to certify these records,so it was not just lockheed propaganda. I don't question the worthiness of the C-130. It's done a great job for a reasonable price. We have not established if it met the original goal but that is of lesser importance to the escalating cost. For example, the C-130E was produced between 1961 and 1964. Lockheed produced approximately 300 C-130s during this four year period. During that time the cost of the C-130E (in 1998 dollars) dropped from an average unit price of approximately $13 million per aircraft to around $6 million. In other words, the C-130E unit price obeyed the classic learning curve theory. However, during the period of 1964 to 1993, the C-130 increased in cost almost 800 percent in unit cost from its low of $11 million to $41 million. The model designation changed from C-130E to C-130H during this period. This cost increase raises the obvious question: either the H model must be more capable or the increase is due to inflation. However, that is not the case in this example. The difference between the two models is minimal and the cited costs are in constant 1998 dollars. In late 1998, the U.S. Air Force was buying seven C-130Hs for $465 million or $66 million a copy. Jim Stevenson ------------------------------ Date: Sat, 26 Jun 1999 18:58:34 +0200 From: Urban Fredriksson Subject: Thrust vectoring Kathryn & Andreas Gehrs-Pahl wrote: > That was in the early 1970s, over 25 years ago, and it wasn't really a > thrust vectoring system, but more an "inflight thrust-reverser". And what > about the F/A-18A HARV, X-31As, and other thrust vectoring aircraft tests > since then? While they achieved pretty good results in 1-on-1 close combat, the nose pointing manoeuvres resulting in missile shots seems to have left the aircraft with TVC in a rather low energy situation and thus rather helpless against the -other- opposing fighter. Doesn't mean it's useless, but I think the main advantages are likely to be: * Reduced trim drag * Smaller control surfaces = lower weight and drag => more speed, range, payload * Stealth as you can sometimes get by without moving aerodynamic surfaces - -- Urban Fredriksson griffon@canit.se http://www.canit.se/%7Egriffon/aviation/ ------------------------------ Date: Mon, 28 Jun 99 02:13:12 GMT From: betnal@ns.net Subject: Re: ATF testing Well, I've been away for a while and this has turned quite lively. I may as well jump back in with a whole bunch o' comments. > I agree that the F-14 is very maneuverable at low and slow speeds. But take the >money for one F-14 and buy F-16s with the same money and your F-14 will die. While I am perfectly willing to discuss the F-14D and other, lesser, fighters, that's really outside the scope of this forum, so I'm going to limit notes on that aircraft to Skunkworks kinda stuff. BTW, the B/D doesn't suffer the out of energy handicap of the A at higher speeds. Regarding the AIM-54B, they were replaced by/rebuilt into AIM-54Cs, the last version. >>It's simply an > >illustration of how much lower the Tomcat's drag was than it appeared and how > >it could do much more than most people believed. >McDonnell Douglas put out this same dribble about its conformal tanks on >the F-15 actually reducing drag. It turned out not to be true. Drag was >actually increased. I'll get back to you on the Tomcat's drag. I can't speak to the F-15 or to conformals proposed for advanced F-16s, but in the case of the Tomcat it has been repeatedly proved in service. That's why you see Tomcats always retaining their under nacelle tanks even when engaging in ACM. It doesn't cost them anything to retain them except the weight. The extra bags of gas are considered worth the weight. >Yes we can and here is why. When, in history, has the Air Force ever >produced an aircraft that met its ORIGINAL spec? All aircraft eventually >meet spec because the services keep lowering the spec to meet the >performance. The ORIGINAL spec is the one that interests me because it >is the figure on which the aircraft was ORIGINALLY justified. Lessee... The F-4 (No wait, that was a Navy plane, never mind). O.K., the A-7 (Oh yeah, ditto). The H-3/53 series (Hmmm, same story). The KC-10? (No, strike that, that plane had already been developed by someone else). Maybe the KC-135, if it hadn't been that Boeing designed it with their own nickel and then the Air Force changed their spec slightly to match it. Hey! I've got 'em! The B-47, B-52 and F-86. See? You've only got to go back around 50 years or so (someone else will bring up the C-130, I'm sure). What's that? You'd like something in the last 30 years? Uhhhh, OK. The SR-71 ('Course it doesn't count since USAF thinks that's a tool of the devil). >In the mid-1970s, Topgun did some experiments on thrust vectoring. It >took two F-11s (F11Fs), one with thrust vectoring and one without. It >put them on the ACMI range and ran the tests. I watched them. The thrust >vectoring was impressive. However, the F-11 without the thrust vectoring >prevailed. I don't thinks that's a fair observation. The original purpose of that thing Rohr hung on the back was to test the benefits of in-flight thrust reverse, which is based on a similar principle but operates differently for different purposes. One of the things the test showed was that while thrust reverse had potential, it had to be designed in from the start or the weight/cost penalties were too severe. The F-11 really couldn't use it to advantage Thrust reverse (ground, mainly) was removed from the ATF specs because of cost, because many of the more advanced technologies were simply eliminated from ATF requirements and because it is an article of bedrock USAF faith that their airfield can't be put out of commission. Requiring thrust reverse to permit landing between the craters would be an acknowledgement that this wasn't so, so 'bye 'bye thrust reverse. The 1950s F-11 had neither the power nor the aerodynamics to take advantage of thrust vectoring. To cite it as proof that thrust vectoring doesn't over major advantages is equivalent to saying that the Bell P-59 proved that jet propulsion wasn't worth it over piston engines. Thrust vectoring offers a number of major advantages. One, it provides control forces independent of airspeed. Second, it permits stability and maneuvering at very high angles of attack offering superior point and shoot. Third, it improves controllability. Fourth, pitch and (with 3D nozzles) yaw are dramatically improved, although the latter may not be worth it. Fifth, it can be used to compensate for damaged control surfaces. Sixth, it can permit smaller conventional controls to be used, making wing/empennage design simpler and cheaper. Seventh it is more "stealthy", although this is the least important reason to use it. Eighth, it can be used to increase sustained as well as instantaneous turn rate. Ninth, it can also be used to reduce stall speed and takeoff/landing run. Advantages eight and nine, though, require some kind of foreplane control surface, such as a canard, to be used effectively. While foreplane controls are quite common in current fighter design abroad, US designers tend to ignore the. Ironically, the one major US design that would have used them (the naval version of the F-23) did not have any provision for thrust vectoring. To take advantage of thrust vectoring, the aircraft must have sufficient power and aerodynamics to use it. The upcoming generation of fighters will. It is under consideration for Typhoon and Gripen (I believe Rafale's engine mounting precludes it), and both JSF variants specify it. Lockheed has offered it on F-16s for export, provided someone foots the bill to qualify it. The SU series is already demonstrating it (India's SU-30s will be so equipped) and it seems to be a shoo-in for the next Russian fighter providing they can raise money to develop them (probably just divert some more of the billions of $ we send them). >Fine. Then we should decide what amount of money we are willing to pay >for uncertainly, and ask the military to give us the best they can for >that amount. In other words, give me the best airplane that $X billion >will buy. A better way would be to decide what it is we really want an airplane/weapon to do to accomplish a mission. Be very specific on that, but Not tell the contractor how to do it. When we get the bill for that, the we decide if doing the mission is worth that. If not, we back off and accept that somethings just can't get done. If you say, "I've got $X to spend", I guarantee you that some contractor will say "Here is the best for that $". They may be right, but you may be wasting the whole $X getting the best value of something that doesn't do what you need. It's no accident that MDD/Grumman essentially refused to try an build their ATA for what the Government wanted, they knew it couldn't be done and why wreck their companies. Although the Government apparently strung them along, they were essentially out of the game by the late year or so. It's also no accident that Lockheed chose not to bid on ATA or NASP, for the same reasons. >I have no objection to R&D. I just want an agreement on how much we are >going to spend in advance, not how much we can run up the bill to >attempt to reach a goal that history tells us the military seldom meets. > As a contractor, if you really want a fixed price contract for >something no one has ever done before I will jack up the cost to try to >cover the uncertainties - or not bid at all. Not to exceed CPFF >contracts are used to try to keep the cost to the customer down. Now, >which way is really in the best interests of the taxpayer? These both are describing another one of Robert McNamara's curses (oops! I should say "legacies", of course): Total Package Procurement (TPP). In this type of lunacy, the Government mostly but with some input from contractors decides what it will cost to research, develop, test and produce something or other. This is then announced as the cost of the program and off we go. This can work if you're buying things off the shelf or adapting existing technologies. However, in Every case where true R&D has to take place, where new things have to be developed, these contracts have been dramatic failures with enormous overruns. In order to get a nice, sometimes arbitrary, set of numbers to announce, too many assumptions have to be made including inflation, infrastructure, what'll happen in the future and especially exactly how much it'll cost to develop something we don't know how to do at the time the numbers are generated. One example (of many) is the C-5. One of the bases for R&D and production as well as wing strength that the Government made was that the contractors would have made available to them a 1,000,000 lb. press. This would allow the centerbody carrythrough to be forged as one unit, making it stronger, lighter and cheaper. th only problem was that there was no 1,000,000 lb. press in existence in the country. However, the contractors were required to bid and design as if there was one. The Government said there would be one by the time needed. As it was, no company was willing to build one for the C-5 program at the price the Government was willing to pay. So, the wing carrythrough had to be assembled from multiple parts and was overweight, weaker (eventually cracking) and cost more. There was no provision in the contract for this (I know. Lockheed made mistakes on its own, elsewhere) so it was classed as an "overrun". The last McNamara driven contract like this was for the F-14, which overran by an amount very close to what Grumman originally said it would cost before the TPP "assumptions" were applied. Conversely, the F-14D came in on time and budget because a more realistic contract was used. TPP died after McNamara, only to be revived in the 1980s by the Reagan Administration. TPP looks real good to the uninitiated because it appears as if everything is "efficiently managed" right form the get-go. As before, development of things that weren't off the shelf went blooey and the money needs started rising. The A-12 was a TPP. >By definition, if it is research we don't know the answer. Research is >also, to a large extent, composed of efforts that don't turn out the way >we would like them to. TPP ignored this truth. What we should be doing today is working on the R&D aspect with no commitment to production until we know the thing is going to do enough to be worth continuing and also have an idea how much it will cost to produce it. Then, we make the decision to go into production, with eyes open. To do this, though, we MUST do our R&D faster. We will save scads of money over the life of the program this way. >> And what >> about the F/A-18A HARV, X-31As, and other thrust vectoring aircraft tests > >since then? >While they achieved pretty good results in 1-on-1 close combat, the >nose pointing maneuvers resulting in missile shots seems to have left >the aircraft with TVC in a rather low energy situation and thus rather >helpless against the -other- opposing fighter. The low energy state came about as a result of very extreme maneuvers. Most of the time you wouldn't do those kind of post stall maneuvers, but just a quick point and shoot. However, it should be kept in mind that a non-TVC won't be capable of those kind of maneuvers at all, and will be much more nervous at the edges of the envelope. TVC can also permit expansion of certain areas of the envelope for much less cost than it would take aerodynamically. But first, you've got to have a plane that has the aerodynamics and power to use it. The F-4 was probably the greatest fighter ever produced, but TVC wouldn't have done a thing for it. Art ------------------------------ End of skunk-works-digest V8 #74 ******************************** To subscribe to skunk-works-digest, send the command: subscribe in the body of a message to "majordomo@netwrx1.com". 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 local-skunk-works@your.domain.net To unsubscribe, send mail to the same address, with the command: unsubscribe in the body. Administrative requests, problems, and other non-list mail can be sent to georgek@netwrx1.com. 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". 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