SU-30 Video
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su30 vid
Does performing these manouvers stress the a/c more than standard flying, that is this short flight probably added more fatigue to the frame than a "normal sortie". Although as a demonstrator it will probably be junked after a few thousand hours anyway.
And how do you stress parts of the a/c that aren't necessarily designed to cope e.g. the radome is meant to point into wind mostly, how does it cope with a 90* aoa (at 300-400kts?) or the sideways motion imposed on it?
It does however look mighty impressive for a big 'un.
And how do you stress parts of the a/c that aren't necessarily designed to cope e.g. the radome is meant to point into wind mostly, how does it cope with a 90* aoa (at 300-400kts?) or the sideways motion imposed on it?
It does however look mighty impressive for a big 'un.
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Bizarrely enough alot of those manoeuvres won't cause as much stress as flying fast followed by a roll and pull.
Rate of change of direction will give the G's and the levels of stress produced will be linked to the amount of kinetic energy of the aircraft.
When an aircraft is designed there is normally a large scale computer model built which will run through the manoeuvres of the aircraft generating the loads for each stage of flight and point in the flight envelope. This normally results in excess of 4000 different loadcases. The worst cases for each of the major axes are selected (both linear forces and moments/torsions) then the parts are stressed for those cases. You'll find that there would have been several cases the apply side loads to the radome and that it is fine. The loadcases can sometimes take into account the additional load of a control surface deflection i.e wing bending due to a max rate roll will include the additional forces generated by the aileron moving.
Hope that was clear ... I'm a bit tired and hope I haven't made a technical faux pas.
Rate of change of direction will give the G's and the levels of stress produced will be linked to the amount of kinetic energy of the aircraft.
When an aircraft is designed there is normally a large scale computer model built which will run through the manoeuvres of the aircraft generating the loads for each stage of flight and point in the flight envelope. This normally results in excess of 4000 different loadcases. The worst cases for each of the major axes are selected (both linear forces and moments/torsions) then the parts are stressed for those cases. You'll find that there would have been several cases the apply side loads to the radome and that it is fine. The loadcases can sometimes take into account the additional load of a control surface deflection i.e wing bending due to a max rate roll will include the additional forces generated by the aileron moving.
Hope that was clear ... I'm a bit tired and hope I haven't made a technical faux pas.
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Rate of change of direction (itself) will not 'give' G - an ac rating at (say) 20 deg/sec could be experiencing (say) 3g or 9g depending on how fast it's going.
At 90 deg AoA the ac is unlikely to be doing 300+ KTS - the speeds involved at these 'bizarre' AoAs are more likely (IMHO/E) to be double figures (or low three figures).
A very impressive machine :-)
Ray
At 90 deg AoA the ac is unlikely to be doing 300+ KTS - the speeds involved at these 'bizarre' AoAs are more likely (IMHO/E) to be double figures (or low three figures).
A very impressive machine :-)
Ray
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http://www.knifeedge.com/forums/down...o=file&id=3768
Will be as close as I will ever Get
John.
Are you talking about FBW or EFCS's? What is the difference ? (I don't know)
I have been told that the SU29 has a auto level System where, if the Pilot becomes disorientated beyond Regain, they hit the switch and the Aircraft will return to Level. what is that ? EFCS or FBW ?
(Not sure on the details of altitude loss for given attitude etc etc. but with the SU 30MK's, I could imagine a EFCSystem where the Aircraft could do a return from Vertical nose down with in 1000feet (Depending on Given IAS at that attitude) : )
Will be as close as I will ever Get
John.
Are you talking about FBW or EFCS's? What is the difference ? (I don't know)
I have been told that the SU29 has a auto level System where, if the Pilot becomes disorientated beyond Regain, they hit the switch and the Aircraft will return to Level. what is that ? EFCS or FBW ?
(Not sure on the details of altitude loss for given attitude etc etc. but with the SU 30MK's, I could imagine a EFCSystem where the Aircraft could do a return from Vertical nose down with in 1000feet (Depending on Given IAS at that attitude) : )
Last edited by BGRing; 15th Dec 2007 at 00:29.
Do a Hover - it avoids G
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All the airframe structural cases (for whatever manoeuvre) will be cleared as not causing any overstress on the aircraft (or pilot) by setting an upper limit on the particular manoeuvre entry speed.
The aerodynamic (stability and control issues) will have been dealt with by normal flight test iterative procedures.
The technical challenges of such manoeuvres actually centre round the engines. You have to keep them running and you must not overstress them with the gyroscopic forces that arise at high rates of aircraft rotation in pitch and yaw.
Avoiding compressor stall due to intake flow distortion at large angles of attack or sideslip requires two things. To quote former MiG-29 chief designer Michael Waldenberg these are a “good basic engine surge margin” and a “suitable” intake. Sadly, an explanation of what is involved in both these topics needs more than a few words. However there is more to a “suitable” intake than is apparent from a casual external inspection.
The overstressing of engine components in high rate manoeuvres first raised its head back in the 1970s when the USMC got the bit between their teeth on the Blot flop air combat manoeuvre during which a Harrier can be made to pitch at rates exceeding 90deg per sec. This turned out to be very much more than the engine had been designed to accept mechanically and was also way outside the AvP970 design standards for military engines at that time.
The aerodynamic (stability and control issues) will have been dealt with by normal flight test iterative procedures.
The technical challenges of such manoeuvres actually centre round the engines. You have to keep them running and you must not overstress them with the gyroscopic forces that arise at high rates of aircraft rotation in pitch and yaw.
Avoiding compressor stall due to intake flow distortion at large angles of attack or sideslip requires two things. To quote former MiG-29 chief designer Michael Waldenberg these are a “good basic engine surge margin” and a “suitable” intake. Sadly, an explanation of what is involved in both these topics needs more than a few words. However there is more to a “suitable” intake than is apparent from a casual external inspection.
The overstressing of engine components in high rate manoeuvres first raised its head back in the 1970s when the USMC got the bit between their teeth on the Blot flop air combat manoeuvre during which a Harrier can be made to pitch at rates exceeding 90deg per sec. This turned out to be very much more than the engine had been designed to accept mechanically and was also way outside the AvP970 design standards for military engines at that time.
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Hovering a MIG 29
I suspect this is not what the MIG 29 designers had in mind.
http://www.youtube.com/watch?v=sFypnPK1dPU
Charles
http://www.youtube.com/watch?v=sFypnPK1dPU
Charles
