Lownverted

My Feedback: (4)

Quoting my own post from January of last year:

I've already done exactly this! I fly UAV's for a living. By nature they navigate via GPS waypoints (ground reference manuvers!) and are very highly instrumented! When turning downwind to final, or upwind to downwind, (our wind limits are 35 kts, which I've flown in many times) there is no change in IAS, ground speed changes of course, but not indicated. Your argument has no credibility. I have telemetry files to back it up.

Once again you are not grasping the issue at hand here, microbursts are NOT steady state wind, which is what this thread is about.

chip_MG

My Feedback: (14)

Jaybird Yes the angle of attack has most to do with the creation of lift.

JackD

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Lowinverted, I'm with you, but I wish it were just the RC pilots... but there are full scale pilots here with the same lack of knowledge (some are even instructors!!!!).
I know that understanding that momentum is relative to the frame of reference when the frame of reference is moving at constant speed is hard... but the stubbornness to learn something different from your own preconceptions is incredible...

I wonder if they also think that when are walking east to west and swithch to west to east you need to compensate for the rotation of the earth ... Actually, imagine that on a bicycle, you would lose your balance (again.. maybe too profound haha)

I give up... But thanks for bringing some fun back to RCU by digging this thread hahaha....

Lownverted

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Thanks Jack...see you at BITW?

JackD

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absolutely!!!!!

Dustflyer

My Feedback: (13)

There are two scenarios: steady state wind and non-steady state wind. There is also the issue of inertia (or lack thereof) and acceleration.

If you are flying at 40 knots into a 40 knot headwind your indicated airspeed is 40 knots. Your groundspeed is zero. If the headwind instantaneously drops to zero what's your groundspeed? Zero. What's your airspeed? Exactly zero until the aircraft accelerates back to 40. In that scenario, the aircraft would stall.

This is why windshear is so dangerous. Airbus aircraft have a feature call "Groundspeed Mini" precisely to mitigate this threat. The Flight Management System will calculate a minimum groundspeed and increase the target approach speed as necessary on final to maintain that minimum groundspeed. This avoids a potentially low energy situation on final in the event of a sudden loss of headwind. GS mini is calculated so that in the event of a sudden loss of headwind, as in a windshear scenario, the aircraft will always be at a safe margin above stall.

chip_MG

My Feedback: (14)

The other day I was watching a TV program called "Air Disasters ". It told of a airline pilot with 156 people aboard crashing a commercial airliner, killing all aboard including themselves. NTSB via the black boxes found the P.I.C. stalled the plane all the way to the ground from 33000 feet to the ground , he held full back press on the control column all the way from 33000 feet to the ground as shown by the black box info.
Hows that for a qualified pilot for ya. Allot of misunderstanding all around about flight just not my guy's who fly models.

Jaybird

I'm not arguing with you, I agree with you. I didn't mention microbursts though, so I assume that may have been intended for other contributors.

Jaybird

Lownverted

My Feedback: (4)

Jay we're all good, I'm agreeing with you too. I just quoted you to show that what you suggested had already been done.

Jaybird

Got it!

Jaybird

rt3232

My Feedback: (6)

Hay Chip-mg

What you posted about falling from 33k may be true, but there were a lot of other problem factors involved in that aircraft that you did not post, and the NTSB may NOT have given all the facts in there public communication.

Just saying post ALL of the facts

Cheers Bob T

chip_MG

My Feedback: (14)

Thats what the program stated the NTSB concluded in their findings was pilot error due to him hold full back pressure. It started because of the plane was too heavy once it got to its altitude was above its ceiling for the weight. So the pilot applied back pressure which he never released, but held it into a stalled condition all the way to the ground.
are you awear of the fight yourself??

mr_matt

My Feedback: (10)

Interesting link. For me, these threads are a study in human psychology, or communications or something. Something about a counter-intuitive reality (airspeed vs groundspeed in this case) can generate such a back and forth. There is something inherent in the question and the basic counter-inuitive explanation that creates such a rich breeding ground for outrageous posts.

FWIW, in my experience, misjudgment of ground TRACK in the landing pattern (in a base leg cross wind favoring the rear of the model) causes many problems. The model needs more bank (and therefore more elevator and AoA) to establish proper ground track on final and poof.

KC Air

Panic mode at 33,000 ft! The explanation I heard for JFK Jr's plane was a similar tale of panic. He became disoriented from the horizon, and was flying banked. As he lost altitude, he pulled back on the yoke, which we all know creates a death spiral in that orientation. Imagine being his passenger, and seeing that he was clueless as you plummet towards the drink. The terror had to show on his face when he pulled back and lost altitude even faster. He probably thought there was something wrong with his plane because he was scared and not thinking clearly.

chip_MG

My Feedback: (14)

If wind speed makes not difference then why do all full scale aircraft manuals state a maximum cross wind component, meaning it's not safe to fly at all if winds are higher?

mr_matt

My Feedback: (10)

Probably has to do with the strength of the landing gear. Groundspeed = airspeed right at landing....If the crosswind is high enough, the required groundspeed (and or crab angle) would be too high for the gear at some point. I am sure a professional pilot can explain it.

drac1

My Feedback: (4)

In a cross wind landing, the pilot will kick the rudder just before touch down to straighten the aircraft to prevent side loading on the gear.

drac1

My Feedback: (4)

If wind has no effect on the aircraft, why does everyone, (full scale and models), take off and land into the wind?

mr_matt

My Feedback: (10)

Maybe not side load but ground speed limit, or tire limit, or the rudder authority available.

rgburrill

The process of a turn is also not steady state wind. Your quads are very highly manueverable and are not at all representive of a winged aircraft.
BTW, show the tlemetry plots! Prove it.

mr_matt

My Feedback: (10)

Lower ground speed and needs less runway

mr_matt

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I am pretty sure he is not flying a quad!

drac1

My Feedback: (4)

It was a general comment about cross wind landings. Of course there is a limit for cross wind landings.

At the correct landing speed, the tires would hold up OK, but rudder authority would be compromised at some point.

drac1

My Feedback: (4)

Exactly Matt.

That's my point. Wind does affect aircraft, although there are comments that say it doesn't.

mr_matt

My Feedback: (10)

HUH? ALL of the comments say that windspeed affects aircraft groundspeed. You are saying the same thing.