Forum: Technology

Modern aircraft, i.e. fighter aircraft 4th gen onwards, use fly-by-wire controls.

If you're flying an FBW-equipped fighter, do you have to be as strong as Hulk Hogan to maneuver it in a supersonic dogfight?

Pierre Sprey thinks so, because he thinks the F-22 Raptor has the maneuverability of a MiG-25 Foxbat, with a turning radius the size of Texas instead of a roundabout.

For Maj. Paul "Max" Moga and Lt. Col. Michael "Dozer" Shower, they don't think so, because maneuvering the Raptor is like playing a video game with a joystick!

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Take whatever Sprey says 'bout the Raptor with a large chunk of salt. Is he a great aero guy? Sure. That doesn't make his opinion the last word on the subject. Yeah yeah I know. He was in the Fighter Mafia and all that but some of his views on the Raptor and other Gen 5 jets makes him sound utterly clueless, IMO. Sprey has NEVER flown the Raptor, supersonically or otherwise. I'd tend to listen to Max and Dozer. They've been there, they've done that. If they say it can be done, it can.

The strength aspect is needed more for G-tolerance, not how much force it takes to move the controls. Remember....you have no direct linkage to the surfaces. You're just a voting member in the loop. The FBW system is what moves the surface thru some actuator. Any load you may feel is artificially induced by the system.

Last edited by skyhigh on May 13, 2009 - 02:55 AM; edited 1 time in total

You mean an onboard computer "flies" your plane, ensuring you, as a Raptor pilot, have full control over the plane close to the point of stalling.

If you have a plane that has mechanical cable controls (e.g. pre-Gen 3 fighter aircraft) you would need to have Hulk Hogan's muscular strength to maneuver a MiG-25 at Mach 2.83+ (3000 km/h), grunting like a weightlifter while the control stick bends out of shape at your hands.

LinkF16SimDude wrote:

The strength aspect is needed more for G-tolerance, not how much force it takes to move the controls.

You mean G tolerance for violent aerial maneuvers?

Forum Veteran Joined: Dec 15, 2006 - 12:28 AM Posts: 760

skyhigh wrote:

You mean an onboard computer "flies" your plane, ensuring you, as a Raptor pilot, have full control over the plane close to the point of stalling.

If you have a plane that has mechanical cable controls (e.g. pre-Gen 3 fighter aircraft) you would need to have Hulk Hogan's muscular strength to maneuver a MiG-25 at Mach 2.83+ (3000 km/h), grunting like a weightlifter while the control stick bends out of shape at your hands.

LinkF16SimDude wrote:

The strength aspect is needed more for G-tolerance, not how much force it takes to move the controls.

You mean G tolerance for violent aerial maneuvers?

G tolerance is not directly related to how much force it takes to move the controls. You seem to be confusing two separate issues.

For the most part it doesn’t take much force to move the controls of boosted or FBW systems. Sometimes the amount of force that is used is artificially increased on some forms of hydraulic assist and fly by wire control systems to give a “feel” of how much force is being applied to the system and how much force is being applied to the control surface.

I’ve heard stories of B-29 pilots and such; where pilots became exhausted just trying to maintain normal flight. I’ve often heard stories of old unassisted/un-boosted heavies; where often both pilots would act in tandem on the controls for hard maneuvering. I’ve often heard stories of old unassisted/un-boosted heavies; where the pilots often take turns at the controls to reduce physical exhaustion.

I seem to remember a story of one of the MiGs we captured, or obtained from a defector. I think it was a MiG-19 or MiG-17. IIRC The American test pilot that flew the captured MiG stated that during hard maneuvers it required so much force and the aircraft was built so lightly that he could feel and see the stick bend/flex.

If you’re traveling at high speed with the modern aircraft the turn radius is not limited by the amount of force than a pilot can apply to the stick; it’s limited by the amount of force that aircraft and pilot can endure. The G force. That’s why traveling at high mach may require a turning radius the size of Texas.

There’s already a thread started on flyby wire.
http://www.f-16.net/f-16_forum_viewtopic-t-212.html

You ought to do a search before starting a new thread on commonly discussed subjects. It's somewhat irritating to have a plethora of threads with the same discussion.

Care to take a guess as to how much force is needed to move the F-16 flaperons and horizontal tails? The hydraulic actuators have a capacity of 50,000 lb each. The flaperons actually use all that force under some conditions. The tails don't use all that force because thay are semi-balanced surfaces (part of the tail is forward of the hinge line, which reduces the actuator force required. All four actuators are the same to reduce logistic costs.

The rudder actuator has much less capability, around 12000 lb, I think.

Forum: Technology

Fly-by-wire controls