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diablopilot

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I spose you're talking about the "touching the ground versus not touching the ground" .. I understand the difference in ground speed and wind speed. But it seems like wind in the nose is more stable than wind in the tail regardless of either speed.



Ask yourself this question:

When you are flying your canopy with the wind (ie in the same direction as the wind) what direction is the relative wind coming from? Do you feel it on your face or on your back?

Think that through and you will have your answer! :)

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I agree with you in terms of instantaneous climb rate. Same issue that pcchapman had above.

I disagree about horizontal movement over the ground. Additional climb rate from a standing wave decays less from a stationary position over the ground, once you've found a sweet spot. If the jump pilot gets extra climb rate from a wave, he'll be in the wave longer when facing into the wind and get more benefit from it.

Here's a question for both of you fellows: which do you think is more important to the jump pilot in question (or any typical jump pilot) - instantaneous or sustained climb rate? Being practical folks, I'm guessing most pilots are talking in terms of sustained climb rate, because that's what actually makes a difference to them.

You both sound like reasonably intelligent guys, but the phrase "deliberately obtuse" keeps coming to mind as I type these replies. I guess my only point is that the pilot may have been right, at least from his perspective. As both an aero engineer and a pilot, I think a lot of engineers could benefit from more practical thinking.

Lance

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I spose you're talking about the "touching the ground versus not touching the ground"



Negative. He is referring to the portion quoting (pointing out) that you are falling, and traveling ("flying") relatively the same, within the same relative airmass. Wind direction at that point in freefall, makes absolutely no difference to you - RELATIVELY, whatsoever. Therefore, which way you are facing, once you have equalized with (within) the airmass (i.e. outside of doing a H&P rather, for instance), makes absolutely no difference at all.

Why is it that everyone takes such great joy in making someone who is asking an honest question, have to GUESS around the answer?
coitus non circum - Moab Stone

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Knew a pilot once who said he always made sure not to turn too fast for a 180 degree turn to create negative airspeed and stall the plane.

I thought he was talking about turning too fast/hard at too high of an bank/AOA to create a stall. Nope, he really thought he could turn around and get negative airspeed over the wing.

*note to self....don't get on the plane with this guy.

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Ask yourself this question:

When you are flying your canopy with the wind (ie in the same direction as the wind) what direction is the relative wind coming from? Do you feel it on your face or on your back?

Think that through and you will have your answer!



I realize that airspeed is a constant. My disconnect is that during opening, the wind resistance on the canopy is greater than the resistance on just the body alone. At some point the canopy begins to pull the jumper forward at it's airspeed. It seems like wind into the nose would slow down the canopy relative to the jumper more than wind in the tail would.

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Ask yourself this question:

When you are flying your canopy with the wind (ie in the same direction as the wind) what direction is the relative wind coming from? Do you feel it on your face or on your back?

Think that through and you will have your answer!



I realize that airspeed is a constant. My disconnect is that during opening, the wind resistance on the canopy is greater than the resistance on just the body alone. At some point the canopy begins to pull the jumper forward at it's airspeed. It seems like wind into the nose would slow down the canopy relative to the jumper more than wind in the tail would.



if you are falling in that airmass, at some point, the canopy "always" begins to pull forward and fly in the direction it's pointed as far as the canopy is concerned - the fact that the airmass and you are moving simultaneously east or west doesn't matter to the canopy while it's falling in that airmass

If you are falling straight down (i.e., moving with the airmass you are in), then as far as the canopy is concerned, you are always starting at zero forward velocity in every direction you may choose to point.

since you realize airspeed is relative, then that actually does clear up your disconnect - turning and facing "north" for example is absolutely meaningless in terms of opening performance


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the wind resistance on the canopy is greater than the resistance on just the body alone



here's your mistake - this is a moot point, the canopy and the body do not 'resist' the winds - they both ride along within it. Until you touch the ground, winds are meaningless in terms of performance in the air. They only matter in terms of how you travel relative to the ground

Here's an exercise - It's a Totally cloudy day and you can't see the ground at all - there's a layer above you and you can't see the sun either - you are surrounded by grey.........You are under canopy.....tell me which direction the wind is blowing relative to you (easy, in my face, and it's the same no matter which way I'm pointing my canopy).....NOW, tell me which direction the wind is blowing relative to the ground (how did you figure that 2nd one out?). You can even have a compass.

...
Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants

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the canopy and the body do not 'resist' the winds



That all makes sense except this part. If that were true, how come I don't fly at the same forward airspeed in freefall as a I do under canopy when I'm in the same air mass?

It seems like the only time the wind matters is during the transition from freefall to canopy flight, when the body's airspeed does not match the canopy's.

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>If that were true, how come I don't fly at the same forward airspeed in
>freefall as a I do under canopy when I'm in the same air mass?

You could if you tracked forward. (And that's the same whether you are facing into the wind or facing against the wind.)

>It seems like the only time the wind matters is during the transition from
>freefall to canopy flight, when the body's airspeed does not match the
>canopy's.

Actually, the only time it matters is when you land.

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I know it doesn't really "matter" until you land, but in the context of this thread, I was saying that there must be a point during opening where the body's airspeed and the canopy's airspeed do not match. So, the forward movement of the canopy relative to the body is not the same which means their airspeeds cannot be the same .. which means .. wind does matter during opening .. however slightly.

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the wind doesn't matter at that time. The body and the canopy have different airspeeds because they have different mass vs. areas (aka "wind resistance" but that's a confusing term in this discussion).

Consider that when you're in the airplane and have just jumped out -- is your exit different on days when it's windy vs. not windy, or can you pull off a stable exit using the same procedure on both days?

I'll submit that in a steady wind, you have no way of knowing what the ground winds are without looking. Turbulence is different, because it's a change in air density in pockets. But the canopy only really cares about the density of the air it's moving through, and not its speed with relation to a third factor (the ground).

Wendy P.
There is nothing more dangerous than breaking a basic safety rule and getting away with it. It removes fear of the consequences and builds false confidence. (tbrown)

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Another laugh is when someone suggests that to get back from a long spot, you want to spread your body wide, to catch air, because the wind is at your back.


And, DigitalDave, don't know if this helps:

When in freefall, after some time has passed after exit, you are moving with the block of air you are in, drifting with the wind. So you may be in a neutral body position by moving over the ground at the speed of the wind. It doesn't matter whether it is moving 5 mph over the ground or 50 mph.

So when you open your parachute, the wind starts off hitting from directly below, whether you are facing upwind or downwind or any direction. The inflation how the canopy starts to fly are unaffected by the wind.


(This all changes slightly when there are changes in the wind at different altitudes. Then issues of drag & inertia come into play, but in most cases, wind shear will have little effect. One has to understand the situation with essentially constant wind first.)

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. It is also an example as to why just because someone is an instructor and has a copy of the SIM why that doesn't make them qualified to teach a canopy course!



Until there is some way to "certify" the people teaching them, there can't and won't be consistency. Compare Brian Germain's course to Flight 1's - and those are experts.

How can qualified local basic canopy skills instructors be developed?

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That applies to takeoff not sustained flight. Aircraft has not stabilized in the airstream.



Um, no. Climb angle (relative to the ground) will be greater when climbing into the wind. This is true regardless of the phase of flight.

- Dan G

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. It is also an example as to why just because someone is an instructor and has a copy of the SIM why that doesn't make them qualified to teach a canopy course!



Until there is some way to "certify" the people teaching them, there can't and won't be consistency. Compare Brian Germain's course to Flight 1's - and those are experts.

How can qualified local basic canopy skills instructors be developed?



Both Flight 1 and Germain teach a good course, they just approach the same learning objectives from different approaches. The same type of survival skills are taught.

Unless you are implying that Flight 1's course isn't as good or isn't as safe as Germain's course, then I stand in strict opposition to your opinion.

AFF-I's have a certification process and there are still AFF Instructors who have absolutely no business teaching students or jumping with them. They just some how passed a course. It doesn't mean they teach anything well or even the right information. A "canopy coach" rating would end up the same way.

Luckily, as it stands now, the canopy pilot community help get people directed towards canopy coaches who are teaching correct techniques and safe courses. Just like the other thread that was asking about canopy coaches and having to hire a "name," it is good to ask around to people in the canopy pilot community if you have a question about a canopy coach. Students will typically end up with a canopy coach who is passionate about canopy flight and teaching.
--"When I die, may I be surrounded by scattered chrome and burning gasoline."

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How can qualified local basic canopy skills instructors be developed?



If only there was some sort of Association, here in the United States that has some overview of Parachutes and the people who use them......

What if it was made up of skydivers, and was in the business of setting rules, regualtions and certifying instructors to teach skydiving to students....

Nah, fuck that. I'm shooting a tandem video on the next load, who's got an upper level wind forecast for 4000' agl? I need to know which direction to face on opening.

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Thanks for explaining this guys. Both in this thread and in PM's. I keep omitting the "moving with the air mass" part from my thought process.

I guess wind would matter in BASE though ?



Yes in that you have an object to avoid relative to your deployment.

Yes in that in a slow speed (sub terminal) deployment you have not accelerated to the motion of the air mass.
----------------------------------------------
You're not as good as you think you are. Seriously.

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. It is also an example as to why just because someone is an instructor and has a copy of the SIM why that doesn't make them qualified to teach a canopy course!



Until there is some way to "certify" the people teaching them, there can't and won't be consistency. Compare Brian Germain's course to Flight 1's - and those are experts.

How can qualified local basic canopy skills instructors be developed?



Have an actual standard to hold instructor candidates too? Have an apprenticeship format? Have a method to weed out the non hackers, after the fact?

Nah, might cut into DZO's bottom line if they had to pay for quality instructors.
----------------------------------------------
You're not as good as you think you are. Seriously.

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Knew a pilot once who said he always made sure not to turn too fast for a 180 degree turn to create negative airspeed and stall the plane.

I thought he was talking about turning too fast/hard at too high of an bank/AOA to create a stall. Nope, he really thought he could turn around and get negative airspeed over the wing.

*note to self....don't get on the plane with this guy.


Actually, that is a true phenomenon, but the airplane has to be flying slowly in a strong wind. Imagine this:

You're flying along at 30 knots into a 25 knot headwind, groundspeed and the airplane's physical momentum are both 5 knots. The pilot then does a quick 180 in a matter of seconds whch isn't too difficult to do with 5 knots of momentum. So, the airplane is turning downwind to a tailwind of 25 knots, AND has to accelerate its physical mass from 5 knots to 55 knots but at an airspeed of negative 20 knots. The airplane will stall at some point in the turn!

--
It's all been said before, no sense repeating it here.

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You must've heard that from me

I always blame it the cross wind when i have off heading opening.
My pack job is solid, my body postion can't be better, then what caused that off heading???
The 40 mph cross wind at 4 grand.
The line twists are caused by wind sheer or dust devil that occurs at 4000
For optimal slow opening, track down wind and pull.
Bernie Sanders for President 2016

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I see what you mean, a standing wave (wave shows no motion relative to the ground) is a special case where lift is not stable with the airstream it is stable with the ground. Generally that isn't what we're talking about in terms of "wind" and lift, it is an exceptional case.
Sometimes you eat the bear..............

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You're flying along at 30 knots into a 25 knot headwind, groundspeed and the airplane's physical momentum are both 5 knots.



Airspeed is 30 knots, and that will control the rate of turn.

Far an airplane to turn fast enough to stall, it literally needs to 'skid' though the turn, seperating the airflow from the wings. That's the basic definition of a stall, and can happen at any airspeed in any wind conditions.

Other than that, it you have 30 knots of airspeed, and you can keep the airflow attached to the wings, you will continue flying.

None of this is mentioning that no certified airplane can maintain flight at 30 knots airspeed, but that's another story.

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Airspeed is 30 knots, and that will control the rate of turn.

Far an airplane to turn fast enough to stall, it literally needs to 'skid' though the turn, seperating the airflow from the wings. That's the basic definition of a stall, and can happen at any airspeed in any wind conditions.

Other than that, it you have 30 knots of airspeed, and you can keep the airflow attached to the wings, you will continue flying.

None of this is mentioning that no certified airplane can maintain flight at 30 knots airspeed, but that's another story.


Yes, there are many airplanes both certified and homebuilts that can fly at 30 knots, not to mention ultralights wihich are required to have stall speeds of 24 knots or less.

How long does an airplane take to accelerate its mass on a runway from 5 knots to 55 knots? And that's without induced drag.

An airplane with an airspeed of 30 knots and a vector momentum of 5 knots can basically turn as fast as a shopping cart.

Bottom line:

Airplane's mass has to accelerate from 5 knots to 55 knots, while airspeed is falling from 30 knots to -20 knots.

--
It's all been said before, no sense repeating it here.

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So I had a skydiving instructor tell me today that before deployment he turns into the wind because it makes his canopy open more consistently.

He was speaking about changing his heading to face into the upper winds. Not for reasons of spot, but just for quality of opening.

Really? Who's selling this stuff?


thats hilarious!


wings? tommy hungry, tommy want wingy!

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