"OVERTALK your picture links suggest that you have a close association with IASA. If that is so, I suggest that you restrict the more extreme views on how to enhance flight safety, however well intention (sic) they might be, to the IASA web site; along with the comments from possible ‘associates’ participating in this thread."
Guilty as charged. It's a widespread secret conspiracy designed to stop runway overruns and restore insurance co profitability, destroy the Brotherhood of Unemployed Overrunners and relieve pressure upon the owners and operators of the 305 marginal runways in the USA alone. You've seen through our shabby ploy. How perspicacious of you. But thanks for the giggle anyway. Keep taking that credibility medication and don't give up on that grammar and syntax primer. The only extreme views I hold are panoramic - from my penthouse suite.
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"your description of back stick "acting against the distant nose-gear fulcrum to lever the main-gear INTO the deck" requires the nose oleo to act as a solid structure whilst the main oleos compress as indicated in your diagram, the result of which will increase the AOA and wing lift, and thus defeats the objective."
I believe that the nose-gear was described as a
dynamic fulcrum. It's not a rigid hinged pivot. In physics it is not unusual for one moment (the sum of the four pitchdown moments) to be counteracted by another moment (the up-elevator opposing moment). I think that it might in combination be called a "couple". The fact that the nose oleo's compression pressure might be eased somewhat by pilot's backstick doesn't mean that the AoA ogre will suddenly take-over and re-launch one luftwards. The reason that it's called a lever is that (for a 2nd class lever), the mid-span resultant is enjoying a significant mechanical advantage). The effectiveness should not be in question. It's basic physics old chap. Try and reconcile with the dynamics of the situation. The amount of backstick is tempered (modulated/introduced) against the degree of braking achieved..... much as in a taildragger.
Couple: A pair of forces acting in parallel but opposite directions, capable of causing rotation but not translation.
"Putting the rotational issues aside, the problem is actually about the transference of load on the gear. Aircraft designs are such that the majority of this is carried on the main gear; the load on the nose gear provides directional control, particularly as airspeed reduces. Thus, as MFS indicates, the % of load that can be transferred to the main gear is proportionally small and depends on many variables in the aircraft geometry and control characteristics. Thus, it is extremely difficult to judge any benefit to be gained, and if any, the effect diminishes rapidly with speed (V*2).
"Effective" weight transference is not about moving the aircraft's mass around like pumping fuel from tail-tank to wings. The backstick uses the ability of the elevator at speed on the runway, very shortly after touchdown, to generate a downwards horizontal stabilizer lift vector which lever-compresses the main-gear oleos and increases the footprint of all main-gear tyres (a very good thing for braking according to Boeing and Airbus - and incidentally also the measure that has most effect upon aquaplaning speeds). Driving the maingear into the pavement significantly increases the tyre surface in contact.... so wheel rotational torque increases, anti-skid becomes less active and braking is thus much more effective.
Ipso (the means)
facto (the indisputable outcome - real and not as you would have it: "imagined" or "simulatored").
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You should take the time to read
this: (the technique would have helped that QF skipper avoid his hole-in-one jumbo).
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Thus, it is extremely difficult to judge any benefit to be gained, and if any, the effect diminishes rapidly with speed (V*2).
And so, I might add, doth runway remaining - if that speed isn't diminished by the most effective means possible. All the useful retardation will happen in that middle third of the runway. Backstick braking over that stretch will extend your lifespan as a professional pilot. Just sit back and think what it might feel like going off the end and through a blast fence at 50 knots with your toe-brakes fully depressed. You are advocating dismissal of a technique that might help avoid that trauma - just because you personally cannot cope with possible change/ come to terms with having been in ignorance for years? You can be a
sceptic without being a heretic.
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"The simple overview is that the majority of the theory is correct, but in practice, there are too many variables for crews to judge. Thus they should not deviate from the manufacturer’s advice.
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I believe this to be what they call "
the neo-Luddite Approach"
You say you agree, but its novelty and other portents (re-introduction of a "new" technique) just strains your brain..... so far better to have the PNF just maintain a religiously neutral stick position after the nose is on - lest the great unknown should up and smite thee for your heresy.
In the fullness of time the industry may re-discover this technique of avoiding overruns. However I must admit that I have little personal faith that this may happen. There is great opposition to change of any sort within the airline industry. But who knows? In five to ten years time, Airbus might have automated the process. Please revisit this thread not before then.
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CHORNEDSNORKACK
Sorry, but I don't understand technical Esperanto. You will have to re-post that in pellucid English prose. If another Ppruner understood what you were postulating and it made sense to him, I'm sure that he will assist by re-positing the theory. I fear that this thread is being intentionally gibberished (a form of obfuscation) in order to denature it, so I'd ask the mods to please now lock it up.