Swing Wing & The Tornado
The most recent swing-wing concept I have seen is a Gulfstream supersonic business jet design. Rationale: low supersonic/transonic drag and low sonic boom combined with high lift/low thrust on takeoff and landing, for both short runways (one of the selling points of a Gulfstream versus a 737 bizjet is that it can get out of a 6000 foot runway) and low noise.
The killer app for swing wings was the ability to combine high speed at low level (and a smooth ride), supersonic speed at altitude, subsonic cruise/loiter and decent runway performance. As some have noted, modern engines and FBW can deliver some of these attributes without the mechanical complexity of swing wings - but also, there is less fixation on the ability to go Mach 1.2 on the deck or Mach 2.5 at altitude.
Overall, swing wings cost more than people expected and delivered rather less, and the aircraft where it was taken to its extreme - mated to an engine that was sized very precisely for high-subsonic on the deck, with lots of fuel-thirsty afterburner for anything else - proved rather less flexible than the aircraft that came a few years later.
The killer app for swing wings was the ability to combine high speed at low level (and a smooth ride), supersonic speed at altitude, subsonic cruise/loiter and decent runway performance. As some have noted, modern engines and FBW can deliver some of these attributes without the mechanical complexity of swing wings - but also, there is less fixation on the ability to go Mach 1.2 on the deck or Mach 2.5 at altitude.
Overall, swing wings cost more than people expected and delivered rather less, and the aircraft where it was taken to its extreme - mated to an engine that was sized very precisely for high-subsonic on the deck, with lots of fuel-thirsty afterburner for anything else - proved rather less flexible than the aircraft that came a few years later.
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Load Toad
This event has probably been covered in the F-4 thread, but the crew-free aircraft landed about 100 yards from QRA with its 3 aircraft fully-loaded in the strike role. In addition, the new hardened shelters were being constructed and the German workers were doing swallow dives off the top of them when they saw the jet heading their way. Gotta laugh, eh?
This event has probably been covered in the F-4 thread, but the crew-free aircraft landed about 100 yards from QRA with its 3 aircraft fully-loaded in the strike role. In addition, the new hardened shelters were being constructed and the German workers were doing swallow dives off the top of them when they saw the jet heading their way. Gotta laugh, eh?
Not sure if this is a difficult question to answer, but I'll try my luck:
Is there a fixed relationship between speed and where you put the wings on a Tornado - as in, "Below this speed you will put the wings here, above this speed you will put them here" - or is it a more complicated situation factoring in what you're doing and what you're about to be doing?
Just idle curiosity.
Phil
Is there a fixed relationship between speed and where you put the wings on a Tornado - as in, "Below this speed you will put the wings here, above this speed you will put them here" - or is it a more complicated situation factoring in what you're doing and what you're about to be doing?
Just idle curiosity.
Phil
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And following that one, I understand that the GR's wingsweep is manual and the F's is auto. So does the auto work properly and put the wings in the optimum position every time?
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Zoom, F3 was originally fitted with auto wing sweep, but problems during testing resulted in it being disabled. So yes it had, no it hasn't and it really wasn't that good. The reality is, that in any 'Tonka' the control of the wings is easy and is learnt within a few trips.
Really, it's a 3 position switch.... Foward for Slow, Mid for Fast Subsonic, Back for Very Fast Subsonic or Supersonic.
Advo
Really, it's a 3 position switch.... Foward for Slow, Mid for Fast Subsonic, Back for Very Fast Subsonic or Supersonic.
Advo
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The true difficulty is memorising all of the various speeds you have to stick to in different sweeps - I am lead to believe that the F111 has a strip ASI which has a little red don't-go-above-this-speed tell-back on it that changes as you sweep the wings. Now THERE'S a good idea!!!
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And then....as well as the speed for each wingsweep, you also have a different G limit and AoA limit. And just when you've learnt them, you strap some underwing tanks on and they all change again!! In reality, it's not that bad and the jet does 'talk' to you if you've got the wings in the wrong place (generally by falling oout of the sky). And those M fit tanks do go super quite nicely!
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Really, it's a 3 position switch.... Foward for Slow, Mid for Fast Subsonic, Back for Very Fast Subsonic or Supersonic.
Funny old thing, the Mig 23 series had only three "locked" positions by memory,
16, 48 and 72 degrees.
And all this in the late 1960's.
Funny old thing, the Mig 23 series had only three "locked" positions by memory,
16, 48 and 72 degrees.
And all this in the late 1960's.
Last edited by RETDPI; 20th Mar 2007 at 04:49.
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Touchin,
Yes, 'M' Fit goes super, even at low level!!
(I would imagine) However, there was a pilot who explained to the Boss, that his 'mild' 'g' overstress in M fit was due to Transonic 'Tuck'........ Hmmmmm Didn't help too much.
Advo
Yes, 'M' Fit goes super, even at low level!!
(I would imagine) However, there was a pilot who explained to the Boss, that his 'mild' 'g' overstress in M fit was due to Transonic 'Tuck'........ Hmmmmm Didn't help too much.Advo
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lol...actually I believe that there were two types of Mike fit tanks originally, sub and supersonic. Rumour has it that there was a screw up to do with the numbering/labelling and as a result they became mixed up and now, not being able to correctly identify which are which, they are all limited subsonic?? Anyone confirm this or is it an urban legend????
Regardless, they still go a bit quicker then my 757 does now!
Regardless, they still go a bit quicker then my 757 does now!
) (I would imagine)
Ecce Homo! Loquitur...
Zoom, F3 was originally fitted with auto wing sweep, but problems during testing resulted in it being disabled.
In particular, the fatigue incurred if the wing sweep changed whilst turning/pulling G was enormous. So, within a couple of days of the system becoming available - a signal went round telling everyone not to use it any more on pain of death.....
IIRC, they had just finished the trials of the autosweep and got a release to service at the same time as they finally decided to wire up the F3 for fatigue trials. They had assumed the GR1, in the LL environment, would run up fatigue faster than the F3. How wrong they were.
In particular, the fatigue incurred if the wing sweep changed whilst turning/pulling G was enormous. So, within a couple of days of the system becoming available - a signal went round telling everyone not to use it any more on pain of death.....
In particular, the fatigue incurred if the wing sweep changed whilst turning/pulling G was enormous. So, within a couple of days of the system becoming available - a signal went round telling everyone not to use it any more on pain of death.....
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For whoever asked earlier -
F-111 - for ops other than takeoff / landing / long range cruise, the rough rule of thumb is wingsweep in degrees to 10% of speed in KIAS.
so 350knots = 35 wing
500 knots = 50 wing.
And yes, the little red barber's pole flag moves with configuration and KIAS / mach number so's you don't overspeed the wings.
Beautifully designed and very user friendly - just have to teach new pilots that there's something else to think about besides throttle!
SW
F-111 - for ops other than takeoff / landing / long range cruise, the rough rule of thumb is wingsweep in degrees to 10% of speed in KIAS.
so 350knots = 35 wing
500 knots = 50 wing.
And yes, the little red barber's pole flag moves with configuration and KIAS / mach number so's you don't overspeed the wings.
Beautifully designed and very user friendly - just have to teach new pilots that there's something else to think about besides throttle!
SW
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Auto Wing Sweep
As far as I am aware the RSAF still use Auto Wingsweep on their Tornado ADV. It is part of the AWMDS (Auto Wingsweep & Manouevre Device System) and when I left the project in 1999 they had not had any significant problems with it.
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All I know is that the less buttons, levers and switches you give a pilot is less for him to break and more time to be admiring his new mirrored raybans in the rear view mirror!!
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Use the wingsweep to control AoA - simple as that.
You want fuel efficiency - sleect a sweep that gives a particulat AoA that gives a particular Range / Endurance etc. You Wan't less Drag??, use wingsweep to select an AoA that equates to that figure. Hint - Know your Min Drag, Best RNG, MNVR, Turning Velocity etc...AoA.
MSMA (F-111 Term) allows a high speed low level pass over land that if utilised correctly will give you a "REDUCE SPEED" light at Mach 0.98. (For a specific wingsweep - know to those in the know) Seem to remember this little device came in handy on more than one occasion when Mum, Girlfriend, Dad, Son et al were watching....
...as for the Tonkas effort - see above comments on Limits with / Without Tanks, MNVR Slat, Under wing stores, Big Jugs, G Limits VNO / VNE blaah blah blahh..
I Thought that F-14 (RIP) auto wingsweep gave the energy state to the bandit - not so much a good idea!!
B-1..... Well what a nightmare in fuel transfer and C of G to sweep wings....
...gimme '60s technology anytime
You want fuel efficiency - sleect a sweep that gives a particulat AoA that gives a particular Range / Endurance etc. You Wan't less Drag??, use wingsweep to select an AoA that equates to that figure. Hint - Know your Min Drag, Best RNG, MNVR, Turning Velocity etc...AoA.
MSMA (F-111 Term) allows a high speed low level pass over land that if utilised correctly will give you a "REDUCE SPEED" light at Mach 0.98. (For a specific wingsweep - know to those in the know) Seem to remember this little device came in handy on more than one occasion when Mum, Girlfriend, Dad, Son et al were watching....
...as for the Tonkas effort - see above comments on Limits with / Without Tanks, MNVR Slat, Under wing stores, Big Jugs, G Limits VNO / VNE blaah blah blahh..
I Thought that F-14 (RIP) auto wingsweep gave the energy state to the bandit - not so much a good idea!!
B-1..... Well what a nightmare in fuel transfer and C of G to sweep wings....
...gimme '60s technology anytime