Firefox Posted November 26, 2003 Share Posted November 26, 2003 I'm thinking of vectoreed thrust control element in EF 2000. What do you think? Link to comment Share on other sites More sharing options...
91WhiskeyM6 Posted November 26, 2003 Share Posted November 26, 2003 Ewww....put the tail fin back hombre Link to comment Share on other sites More sharing options...
Commander McBride Posted November 26, 2003 Share Posted November 26, 2003 Naw, that's pretty cool! It looks like, what was it, the X-31 with no tail? Link to comment Share on other sites More sharing options...
Aegis! Posted November 26, 2003 Share Posted November 26, 2003 Wow , nice , is that Dover I see in the background ? mmm , no it isn´t , but it´s certainly England though (just look at the lack of sunlight ) Link to comment Share on other sites More sharing options...
Druna Skass Posted November 26, 2003 Share Posted November 26, 2003 Ewww....put the tail fin back hombre Well put SOME kind of fin on it... It just don't look right... Link to comment Share on other sites More sharing options...
rocco_77 Posted November 26, 2003 Share Posted November 26, 2003 ooo.... yyyeah.... needs a tail fin... Link to comment Share on other sites More sharing options...
VF-19 Posted November 26, 2003 Share Posted November 26, 2003 Interesting... If I'm thinking right, the lack of a vertical fin allows for a better stealth profile. However, a plane doesn't "need" a rudder to fly. It will still work, just don't get yourself into spins and stalls... Link to comment Share on other sites More sharing options...
Apollo Leader Posted November 27, 2003 Share Posted November 27, 2003 Here's the X-31 flying with its tail removed and using thrust vectoring instead: Link to comment Share on other sites More sharing options...
the white drew carey Posted November 27, 2003 Share Posted November 27, 2003 Here's the X-31 flying with its tail removed and using thrust vectoring instead: Now that's a bad photoshop. Link to comment Share on other sites More sharing options...
David Hingtgen Posted November 27, 2003 Share Posted November 27, 2003 (edited) EF2000 thrust vectoring will look like this: http://www.eurofighter.starstreak.net/Euro...er/engines.html (very nifty design, better than an ACTIVE nozzle) Also, if you want a tail-less plane, it better be a flying wing. You need a WHOLLY different control system. Vectoring isn't used for yaw. Pitch-yes, roll-yes, yaw-no. It CAN be used for supplemental yaw, usually combined with pitch and or roll. But no plane uses vectoring for yaw alone, not yet. Yaw is just plain different than other forces on a plane. Don't know why, just always has been. There's a difference between yaw control and yaw stability. Vectoring can replace control (but it hasn't yet) but it'll never replace stability. (Not until we have like Star Trek level of tech) If you plan to remove the v.stab, you better attach some massive ventral fins. (Unless you've got a flying wing and are using split-style elevons--flying wings are SO stable and so un-influenced by yaw they can be tail-less---but a normal plane cannot have the stab removed) Normal planes simply need X amount of vertical surface. Check out early F-14, F-15, and F-16 designs. You'll see plenty of swapping between "ventral fins+1 stab" versus "no ventral and 2 stabs". (And even the "2 small stabs with 2 small ventrals to make up for the shortened stabs"---looked kind of cool on the F-15). YF-23's get away with it by having MASSIVE tails, to counteract their low angle. (Plus they do have B-2 style split ailerons for yaw control--a YF-23 does fly like a flying wing, even if it doesn't look like one--it uses opposing ailerons for drag-based yaw control) (A YF-23's tail still has no technical name AFAIK--it is not a ruddervator, nor a taileron---it is simply "an all-moving canted tail surface"---Pelikan tail has come up as a rejected F-32 tail, but it's not quite the same, but still obviously based on the -23's tail) Edited November 27, 2003 by David Hingtgen Link to comment Share on other sites More sharing options...
Apollo Leader Posted November 27, 2003 Share Posted November 27, 2003 (edited) Doh! I feel stupid. I thought the X-31 had been flown tailless sometime during the last decade, but this picture and the other picture at the Dryden we site are indeed just "concepts". Here's a quote from gloablsecurity.org: In 1994, software was installed in the X-31 to demonstrate the feasibility of stabilizing a tailless aircraft at supersonic speed, using thrust vectoring. This software allows destabilization through the control laws of the aircraft in incremental steps to the goal of simulation 100 percent tail-off. Quasi-tailless tests began in 1994. The first phase started with supersonic evaluations at Mach 1.2. Later subsonic evaluations were performed. During the flights the aircraft was destabilized with the rudder to stability levels that would be encountered if the aircraft had a reduced size vertical tail. The quasi-tailless testing provided data to industry on the benefits of drag reduction, radar cross section, and weight reduction that could be used for future commercial and military designs and modifications. Simulated tailless X-31 flight tests conducted for the Joint Strike Fighter program successfully provided an initial demonstration that thrust vectoring could provide yaw control and, thus, reduce or eliminate the need for an aircraft vertical tail. Edited November 27, 2003 by Apollo Leader Link to comment Share on other sites More sharing options...
David Hingtgen Posted November 27, 2003 Share Posted November 27, 2003 Ah ha. Yaw *control*, not yaw stability. You'd need something like the F-16's pitch control system to eliminate the v.stab to replace stability----- 100 deflections a second. Thrust vectoring is nowhere near that, and won't be for a long time, since you simply cannot deflect the exhaust of a 30,000lb engine at that rate. Link to comment Share on other sites More sharing options...
91WhiskeyM6 Posted November 27, 2003 Share Posted November 27, 2003 To mutilate the EF2000 like that along with the X-31? that's just plain desecration! On the other hand, this one looks awesome... Bird of Prey prototype from Boeing: Link to comment Share on other sites More sharing options...
Nied Posted November 27, 2003 Share Posted November 27, 2003 EF2000 thrust vectoring will look like this:http://www.eurofighter.starstreak.net/Euro...er/engines.html (very nifty design, better than an ACTIVE nozzle) Also, if you want a tail-less plane, it better be a flying wing. You need a WHOLLY different control system. Vectoring isn't used for yaw. Pitch-yes, roll-yes, yaw-no. It CAN be used for supplemental yaw, usually combined with pitch and or roll. But no plane uses vectoring for yaw alone, not yet. Yaw is just plain different than other forces on a plane. Don't know why, just always has been. There's a difference between yaw control and yaw stability. Vectoring can replace control (but it hasn't yet) but it'll never replace stability. (Not until we have like Star Trek level of tech) If you plan to remove the v.stab, you better attach some massive ventral fins. (Unless you've got a flying wing and are using split-style elevons--flying wings are SO stable and so un-influenced by yaw they can be tail-less---but a normal plane cannot have the stab removed) Normal planes simply need X amount of vertical surface. Check out early F-14, F-15, and F-16 designs. You'll see plenty of swapping between "ventral fins+1 stab" versus "no ventral and 2 stabs". (And even the "2 small stabs with 2 small ventrals to make up for the shortened stabs"---looked kind of cool on the F-15). YF-23's get away with it by having MASSIVE tails, to counteract their low angle. (Plus they do have B-2 style split ailerons for yaw control--a YF-23 does fly like a flying wing, even if it doesn't look like one--it uses opposing ailerons for drag-based yaw control) (A YF-23's tail still has no technical name AFAIK--it is not a ruddervator, nor a taileron---it is simply "an all-moving canted tail surface"---Pelikan tail has come up as a rejected F-32 tail, but it's not quite the same, but still obviously based on the -23's tail) Not necesarily David. There have laready been several proposals for tailess aircraft, the afore mentioned X-31 modification (though the final stage where the tail was physically removed was axed for budgetary reasons), two F-22 variants (the X-44 MANTA, and the FB-22), Boeing has already flown the tailess X-45 UCAV, as has Northup-Grumman with thier Pegasus, and finnally Lockheed just proposed a modified F-16XL as a tailess research craft. Three of these aircraft are attempts at creating operational combat aircraft, not just X-plane flights of fancy. The MANTA is probably the most interesting though, since it proposes to control the aircraft entirely by TVC. Link to comment Share on other sites More sharing options...
David Hingtgen Posted November 27, 2003 Share Posted November 27, 2003 X-45 has always struck me as flying-wing-ish. (Mainly in profile). I'm unaware of those F-22 proposals. Let me know when there's a tail-less F-22 flying through turbulence. As I said---there will someday be utterly tail-less non-flying-wing (aka normal) planes, but not until there's a huge jump in TVC technology. (Mainly speed of actuation/deflection). Of course, tech does tend to jump pretty fast... Link to comment Share on other sites More sharing options...
Nied Posted November 28, 2003 Share Posted November 28, 2003 I don't know what to tell you, these things have been proposed and in the case fo the X-31 it's been tested (though they had to program the rudder to simulate the lack of a rudder). X-44 MANTA FB-22 X-31 (14th paragraph) F-16X Link to comment Share on other sites More sharing options...
David Hingtgen Posted November 28, 2003 Share Posted November 28, 2003 Seems most of those use B-2/flying-wing style drag-inducing ailerons for yaw-control. You still can't just chop off the v.stab and have it fly using vectoring alone. (X-31 with "simulated" lack of v.stab doesn't count) Link to comment Share on other sites More sharing options...
Nied Posted November 29, 2003 Share Posted November 29, 2003 Seems most of those use B-2/flying-wing style drag-inducing ailerons for yaw-control. You still can't just chop off the v.stab and have it fly using vectoring alone. (X-31 with "simulated" lack of v.stab doesn't count) Again I don't know what to tell you. Lockheed seems to think it's possible. And why doesn't the X-31 count? How is the TVC reacting to random destabilizations caused by the rudder any different than it reacting to random destabilizations caused by no rudder at all (or the Vertical Stabilizor it's attached to). Everything I've read says that the engineers were confident they could go ahead with loping the tail off the X-31, they just didn't have the budget to do it. Link to comment Share on other sites More sharing options...
Nied Posted November 29, 2003 Share Posted November 29, 2003 Bill Sweetman wrote an article on this (who else would?) The X-31 program uses standard vecotring techniques, the X-44 is supposed to as well, at least at first. Go down to the fith paragraph under the heading of Supersonic cruise bypass Flights of fancy take shape Link to comment Share on other sites More sharing options...
David Hingtgen Posted November 29, 2003 Share Posted November 29, 2003 I simply am not confident that a rudder flapping around to simulate the lack of a rudder and v.stab, is the same as it actually not being there. I mean, flopping an aileron about doesn't 100% simulate lack of wing since the wing's still there making lift, even if the trailing edge is changing it... A v.stab/rudder still has some influence on rolling etc, even if the the rudder is inducing yaw motions. Big factor in the DC-10 design. It wasn't so much the yaw effects from the rudder due to the engine in the tail, it was the rolling motion due to the strange position of the rudder. Also, "we're sure it'll do it, it just didn't actually do it" is the kiss of death for a lot of things. See YF-23 aerobatics... Link to comment Share on other sites More sharing options...
Max Jenius Posted November 29, 2003 Share Posted November 29, 2003 Firefox, you can start one thread in the fanworks section where you can put ALL of your art. Don't post a new thread every time please. Link to comment Share on other sites More sharing options...
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