Am I the only one who's missing something?
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Don’t worry, you’re not coming off as hostile. And you’re correct things have changed since that manual was written–personally I say scrap that part of the manual entirely because your approach/landing speed varies greatly depending on your weight, and the AoA bracket is still valid once the wheels are on the ground. Scraping only occurs at or above 15* AoA. Not sure if it’s at or above though.
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While on the ground the FPM could be wrong from wind angled down to ground or wake turbulences from another a/c. The AoA sensor is external.
The guncross is rendered somewhere at near 0* wing means incidence. The pitchladder is rendered with INS data. Both are internal.
In r/l HUD video, the FPM and AoA bracket bounce together while rolling on the ground. Looks like vibration. The top bracket of the is not always on the 13* pitchladder. Guncross/Pitchladder and FPM/AoA bracket can show different information. I’ve tried to switch to Guncross/Pitchladder but my eyes are glued to the FPM.
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Are you measuring this on runway, or still airborne? If in air nevermind. The origional manual stated 11deg aoa @ 160kts, then flare at 100’ above the runway to 13 deg aoa GENTLY, keeping airspeed at 130kts until touchdown, with speed brakes still fully open. If you exceeded 15 aoa the speedbrakes would scrape. It was also stated to pull the gun cross to the 10 deg pitch line on the hud to aero brake, as the FPM got unreliable once on ground (weight on wheels). I know stuff has changed since that was written, the speed brake retracts some now with gear down. But you will still scrape the can reguardless of AOA if your a/c pitch on ground is above say 12 deg’s. Let the nose come down around 110 kts while you can still control the nose. Again, I realize pre-touchdown you use the bracket in the hud, but once the wheels are on the ground and your speed is slower the bracket becomes unreliable. I’m not trying to argue with your in-air procedure, just pointing out that with WOW you can only maintain so much pitch before you do dammage, the cross is more relavent on the ground to me. In theory it is where the nose is pointed - keep it as a reference. Again, appologies if I’m coming off as hostile or arrogant, not my intent. I don’t know the fall off point of the fpm on the ground, but the gun cross is constant, and AOA is a direct relationship between the two, if I recall correctly.
real pilots use the AOA bracket to aerobrake at 13 AOA …so better to do the same
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real pilots use the AOA bracket to aerobrake at 13 AOA …so better to do the same
I guess if the runway is not built level and is on a 3* grade, the gunX shows 13* twhile the tail scraping at 16*.
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A 3* grade is going to be gradual over the entire distance of the runway….
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maybe “grade” is the wrong term?
If the runway is built 3° off a level plain…… -
A 3* grade is going to be gradual over the entire distance of the runway….
…and?
that still means that your AoA will be different to the elevation of the gun cross.
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…and?
that still means that your AoA will be different to the elevation of the gun cross.
That depends on if we are talking a runway that starts from 0* and rises up to 3* at a certain point or if it is 3* in its entirety as caper said a second ago.
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well a 3 degree grade is a constant grade of 3 degrees…
in both cases, the gun cross would still be an unreliable indicator of how close you are to a tail strike.
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“Grade” refers to rise and run that creates a right triangle. It’s measured in %.
A 3° pitch = 5% grade.
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“Grade” refers to rise and run that creates a right triangle. It’s measured in %.
http://www.angelfire.com/ultra/mathproject/images/gradesign.JPG
A 3° pitch = 5% grade.
bah, this crap is why im not a rail engineer…
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or racket scientist.
I worked with one aerospace engineer (grad student) that kept talking about how “frequency” effects all this Greek stuff on a rotorwing platform. I recognize some of the Greek symbols/terminology but “frequency” I had no idea. None of the other grads, field engineers or PHDs were using “frequency”. After a few months I asked WTF does frequency have to do with helicopter. “frequency” = rotor rpm.
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bah, this crap is why im not a rail engineer…
….or racket scientist.
I worked with one aerospace engineer (grad student) that kept talking about how “frequency” effects all this Greek stuff on a rotorwing platform. I recognize some of the Greek symbols/terminology but “frequency” I had no idea. None of the other grads, field engineers or PHDs were using “frequency”. After a few months I asked WTF does frequency have to do with helicopter. “frequency” = rotor rpm.
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or racket scientist.
I worked with one aerospace engineer (grad student) that kept talking about how “frequency” effects all this Greek stuff on a rotorwing platform. I recognize some of the Greek symbols/terminology but “frequency” I had no idea. None of the other grads, field engineers or PHDs were using “frequency”. After a few months I asked WTF does frequency have to do with helicopter. “frequency” = rotor rpm.
He probably meant the vibrations caused by the rotor/rotor RPM.
Anyway, the last time I studied ‘grade’ was 11 years ago in Driver’s Ed….and I didn’t pay any attention because my area is completely flat.
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That’s what I was thinking. Next to our lab was a structure lab working on an active system to decrease vibration on the F-15’s vertical fins. I thought he was one of those structure engineer drifting into our lab.
He was saying stuff ei. “increase frequency to deduce alfa to generate more lift.”
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Makes sense to me.
If an airfoil would vibrate at a low freq, I can imagine the airflow has a hard time staying laminair thus will become turbulent and generate less or no lift.
If there is no way to decrease the freq…increasing is a lot could have the same effect. -
“increase frequency to reduce alfa to generate more lift.”
He was saying run the rotor head at a higher r.p.m. and reduce rotor blades AoA.
It’s like reading a car tachometer in Hz. (cycles/sec) that’s not like a Euro/metric thing?*With those adjustment the vibration freq and amplitude would possibly increase. But he wasn’t taking about vibration. geeee
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Units of measure define if it is a metric or english thing. (A tach. is revolutions per min., usually, so I’d be willing to say same diff., just divide rpm by 60 sec) Getting off topic, sorry. Yes I meant in relation to the runway being PERFECTLY FLAT and LEVEL. IRL that is hard to control, ever drive over a frost heave in a cold climate? The runway is usually close enough to be thought of as level, I’d guess in most cases. Viewing the ones in AIR AMERICA may prove otherwise, however.
-Babite -
Oh, I forgot to mention one thing: Y O U G U Y S S U C K !!!