fly-by-wire
Join Date: Apr 2002
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As Acer said a couple of days ago, the NH90 is the ONLY Full Fly-By-Wire helicopter in production today.
The RAH-66 was indeed an advanced FBW system, but the program has been cancelled and therefore it does not count anymore.
The NH90 is using a double attitude reference system with Ring Laser Gyro's which provides the input for the FBW system. There is a third one as backup (if all else fails).
The output to the Main Rotor Actuators is indeed analog, but the control laws can still be tuned to the needs and you can get rid of nasty coupling effects (so it is not only for basic damping etc.).
Of course other manufacturers are experimenting with FBW and in time this will probably be common practice...
The RAH-66 was indeed an advanced FBW system, but the program has been cancelled and therefore it does not count anymore.
The NH90 is using a double attitude reference system with Ring Laser Gyro's which provides the input for the FBW system. There is a third one as backup (if all else fails).
The output to the Main Rotor Actuators is indeed analog, but the control laws can still be tuned to the needs and you can get rid of nasty coupling effects (so it is not only for basic damping etc.).
Of course other manufacturers are experimenting with FBW and in time this will probably be common practice...
NH-90
Has NH Industries flown their aircraft without mechanical backups? All discussions I have seen indicate that their developmental vehicles all had mechanical backups. By comparison the RAH-66 was purely FBW from the get go.
Join Date: Dec 2001
Location: Philadelphia PA
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Canada's National Research Council Institute for Aerospace Research has had fly-by-wire in their variable stabilty helicopters for more years than I care to remember. Started with a Bell 206, moved up to a Bell 205, now have a Bell 412. All modes of fly-by-wire can be demonstrated from the right seat - including 4 axis on one control. amazing. Most fun you can have in a helicopter with your clothes on. But the NH-90 is the first production helicopter as far as I know.
Join Date: Apr 2003
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bockywocky missed the point that I made. The basic architecture of the NH 90's FBW is that all computations are made in a pair of analog computers that match the outputs of a pair of digital computers. Any miscompare shuts down that lane. This means that the FBW on the NH90 is incapable of doing anything that can't be done with resisters and capacitors. It is therefore relegated to damping and making normal helo flight controls, basically 1975 flight controls, in spite of the fact that it is a FBW.
Nonetheless, it is in production, and so it counts, as does the V22
Nonetheless, it is in production, and so it counts, as does the V22
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Analog ~ Digital. They both use wires.
The foundation of a Digital computer is the storage and manipulation of bits [on/off]. Whether that bit is On or Off depends upon the Analog value of the bit's voltage, which is increased, stored, refreshed, decreased, and read.
The 'bit' is a very small capacitor and resistor.
The foundation of a Digital computer is the storage and manipulation of bits [on/off]. Whether that bit is On or Off depends upon the Analog value of the bit's voltage, which is increased, stored, refreshed, decreased, and read.
The 'bit' is a very small capacitor and resistor.
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For the record:
The first prototype of the NH90 (PT1) did not have FBW.
The other four prototypes (PT2 - PT5) have or had FBW controls on the left side and mechanical back-up on the right.
Indeed since december 2003 PT3 was the first NH90 to fly Full FBW and later also PT4 was coverted to Full FBW.
All production helicopters of the NH90 have Full Fly-By-Wire controls.
The big advantage that i see with FBW is that you can get rid of the cross-coupling effects of mechanical controls by programming the control laws the correct way.
For your information: it flies very nice
The first prototype of the NH90 (PT1) did not have FBW.
The other four prototypes (PT2 - PT5) have or had FBW controls on the left side and mechanical back-up on the right.
Indeed since december 2003 PT3 was the first NH90 to fly Full FBW and later also PT4 was coverted to Full FBW.
All production helicopters of the NH90 have Full Fly-By-Wire controls.
The big advantage that i see with FBW is that you can get rid of the cross-coupling effects of mechanical controls by programming the control laws the correct way.
For your information: it flies very nice
