Losing altitude in your carves in wind versus no wind

[CanuckInUSA 0]

Here's a question which has bugged me for a while. It appears that when I jump in some fairly strong (yet constant) winds and I am performing a carving front riser turn, I tend to lose more altitude that if I was jumping in low to no winds. Is this something to be aware of, or am I just out to lunch as the canopy will lose the same amount of altitude no matter what the winds are doing.

Try not to worry about the things you have no control over

[Hooknswoop 19]

It's only perception. You are a pilot, think of it this way: You are in a C-172 and bring the power to idle and maintain 70 kts. That will give you a steady descent rate, somewhere near 500 fpm. It doesn't matter if you are bucking a 70 kts headwind or have a 70 kts tailwind, the 500 fpm won't be affected. Wind only affects groundspeed.

Derek

[CanuckInUSA 0]

Thanks for the info ... I thought it might be me, but I just had to ask.

Try not to worry about the things you have no control over

[rigging65 0]

Like Derek said, it's just your perception. Since you're used to covering a certain amount of ground in your swoop given a certain amount of time, if you cover less ground in the same amount of time, your brain tells you that you must be descending faster than normal...when in actuality, it's just the head wind slowing your forward progress.

Silly brain, trix are for kids!

"...and once you had tasted flight, you will walk the earth with your eyes turned skyward.
For there you have been, and there you long to return..."

[johnny1488 1]

I spoke w/ Scott Miller at lenght about this. Your canopy doesnt know if there is 70kts of wind or no wind at all. It only knows the inputs the pilot gives it.

Now in turbulence, all bets are off.

Johnny
--"This ain't no book club, we're all gonna die!"
Mike Rome

[SBS 0]

But, if you are doing a long, drawn out, carving turn, the top of your canopy will be presented to the wind longer than in a snapping turn (for example), thus making a difference to your decent rate in wind vs. no wind...

In other words...wind will not make much difference to a snapping turn...but, will make a difference in a carving turn.

-S

_____________
I'm not conceited...I'm just realistic about my awesomeness...

[TB99 0]

The question was if you did a carving turn ... no matter what the winds are, you will lose the same amount of altitude if you do the same exact turn ...

The question of carve vs snap wasn't even an issue in this poll, maybe another thread can be started if you want

Trailer 11/12 was the best. Thanks for the memories ... you guys rocked!

[SBS 0]

I presented an answer to the question that I believe to be true, based on my personal experience as well as the experience of my mentors. That experience is that in a long carving turn, you do lose more altitude at a faster rate when there is wind, because of the wind being presented to the top of the canopy. I offered the difference of the snap vs the carve as a point of reference.

I believe the information was perfectly relevant to the conversation.

I edited the post to try to make it more clear what I was trying to say...sorry if it was unclear, I hope it's better now.

-S

_____________
I'm not conceited...I'm just realistic about my awesomeness...

[TB99 0]

I see now, that is relevant ... are you saying that performing the same exact identical carving turn in no wind and in high wind will account for more altitude loss??? As well as the same exact snap turn in both situations will result in a difference one way or another??? If so, I believe your theory is off ... the wind does not affect altitude loss either way, carve or snap ... the wind will crab you off your line (moreso in a carve), but you'll lose the same amount of altitude either way! Someone who actually knows better, please chime in?

Trailer 11/12 was the best. Thanks for the memories ... you guys rocked!

[grega 0]

No the altitude loss is the same.

I have a great example explaining this:
Take small aquarium full of water.
then take a small rock (representing a skydiver making a turn) Put it in the aquarium. Count the time that it needs to get to the bottom of aquarium full of water

Now lift the aquarium with your hands and move it over the ground with constant speed. this is impossible with bare hands, you'll probably make waves and water will be moving forward and backward. but let's say that you somehow manage to move that aquarium with constant speed. now this movement of water inside the aquarium presents the wind (water is liquid just like air only more dense, and the wind is nothing else but moving air over the ground). now put the rock again in the moving aquarium. the time that it needs to get to the bottom will be exactly the same. If you look at the rock away from the aquarium it won't fall straight down, because it was moved sideways with the water (wind). if you look at the rock within the aquarium. it will move exactly the same as if the aquarium wasn't moving (no wind), but through the bottom of the aquarium you can see the ground moving, but the rock is still moving the same as the aquarium would be still (no wind)...

Hope that makes any sense...

again, we are talking about wind with constant speed, if wind changes speed (accelerations, decelerations) like in turbulence, then we have a lot more to say about different masses (skydiver-heavy, parachute-light)...
But this is for another thread

"George just lucky i guess!"

[johnny1488 1]

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you do lose more altitude at a faster rate when there is wind, because of the wind being presented to the top of the canopy.

Your canopy doesnt know there is wind presented to the top skin. It knows nothing about wind. There is more wind at alltitude than you would ever jump in on the ground. If that were true, your canopy wouldnt dive at all up top, right? The only factor here is in stronger winds, you most likely arent moving over the ground at the same rate because your ground speed would be different than you're used to(the only difference clean wind makes) and you will most likely not use the same amount of input. Pilot induced.

Johnny
--"This ain't no book club, we're all gonna die!"
Mike Rome

[craddock 0]

I would hardly call comparing a rock to a ram air canopy with forward movement a great example. It really does nothing to counter those who feel the wind exposed to the top of the canopy uring a turn make it dive harder. Rocks fall with the pull of gravity. Canopies fly.

That spot isn't bad at all, the winds were strong and that was the issue! It was just on the downwind side.

[grega 0]

it's not the point about the rock, but about what the wind avtually is and what it does.
it doesn't matter if it's a rock, a fork, remote control, a boat, or canopy if you will.
I was trying to make an example what wind is and that it does not effect your movement in the constant wind (moving aquarium) at all. everything in constant wind moves the same like there was no wind. relative to the wind itself not the ground of course...

"George just lucky i guess!"

[PhreeZone 15]

Why am I reminded of the "Canopies want to open downwind" arguement right now?

The canopy is moving in an airmass that is also moving. As such the only place where the canopy knows that it is moving in the airmass is where it touches the ground. If you look away from that point you realise the canopy is the same no matter is there is wind or not since the canopy does'nt get "pushed" from the wind.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[Hooknswoop 19]

Wind only affects ground speed, not airspeed and not rate of descent. The wind does not "hit the top of the canopy". The aquarium analogy is a good one.

A Cessna in a 500-fpm descent indicating 80-kts with a 80-kt tail wind turns 180-degrees and the pilot changes nothing else. The airspeed indicator will still say 80-kts and the VSI will still read 500-fpm. The Cessna’s ground speed will have gone from 160-kts to zero-kts.

Take a fish bowl. A goldfish in the bowl swims at 1-mph. Now take a imaginary car with awesome suspension and a very smooth road. Put the fishbowl on the floor board and drive at 30-mph. The fish swims towards the front of the car at 1 mph. It’s ‘water speed’ is 1 mph, it’s ground speed is 31-mph. The fish only feels the 1-mph. If it swims towards the rear of the vehicle, it’s ‘waterspeed’ is 1 mph and it’s ground speed is 29-mph. The entire time it only feels like 1 mph to the fish. It has no way of knowing or feeling it’s ground speed.

It is the same thing for a canopy. Wind is a large mass of air moving over the ground (fish bowl in a car). We fly within this moving air mass. Just like the fish, we only feel our airspeed, and only know our ground speed changes because we can see the ground.

Take a canopy with a 30-mph forward speed. Fly it into a 30-mph headwind. It’s airspeed is 30-mph and it’s ground speed is 0-mph. It still flys and feels like 30-mph even though it is not moving over the ground. It doesn’t fall out of the sky because it’s ground speed is zero. It’s airspeed is still 30-mph, but it’s ground speed is 0-mph. Same canopy, same conditions, except turn downwind. No difference in the turn, it’s airspeed was 30-mph at the beginning of the turn, it will loose the same amount of altitude in the turn regardless of it’s ground speed or the winds. It’s airspeed during the turn will be exactly the same as if there was zero wind. With the 30-mph tailwind, it’s airspeed is still 30-mph, but it’s ground speed is now 60-mph.

Again, wind only affects ground speed, not airspeed and not rate of descent.

Derek

[craddock 0]

Just for the record when I said this:

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It really does nothing to counter those who feel the wind exposed to the top of the canopy uring a turn make it dive harder.

I was in no way including myself in that group.

Some of them that do feel that way have thousands of jumps and I did not feel that the rock example was going to get them to understand after all these years. Perhaps rather than implying it was a bad example, I should have said I thought it was an ineffective example. I think those who feel it is a good example are the ones that do not need to be conviced.
Regardless, I could care less about trying to convince someone experienced that they hae been wrong for their entire sydiving career. It's not hurting anyone. (unless they are instructors I guess)
Josh

That spot isn't bad at all, the winds were strong and that was the issue! It was just on the downwind side.

[Pasha 0]

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Wind is a large mass of air moving over the ground (fish bowl in a car). We fly within this moving air mass. Just like the fish, we only feel our airspeed, and only know our ground speed changes because we can see the ground.

Does this mean that you cannot determine the wind direction unless you see the groud?

[Hooknswoop 19]

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Does this mean that you cannot determine the wind direction unless you see the groud?

Correct. If your canopy flys at 30-mph airspeed, then regardless if you are backing up over the ground or doing 65-mph, you’ll only feel 30-mph wind. Imagine if you are over a solid cloud layer, you wouldn’t know if you were backing up or zooming across the ground. You could only feel the 30-mph of wind, regardless of your ground speed. With only the cloud as a reference (and the air mass you are flying in) you could only sense your airspeed, not your ground speed.

We determine wind direction by our drift over the ground. If we are going very fast, we have a tailwind, slow and we have a head wind, drifting sideways, a crosswind. We need the ground as a reference for determining our ground speed. Without it, we do not have enough information to determine which direction the mass of air we are flying in is moving over the ground.

Derek

[SBS 0]

We are not talking about ground speed here...I totally agree with you, that the ground speed will change, but the air speed will remain the same.

Of course the canopy knows that wind is hitting the top skin...and the longer the top skin is presented to the wind, the more it will affect your decent. The only way, in a dive, that the canopy would not know the difference, is if the wind was coming straight up from the ground.

That is not to say that the canopy will not dive if there is not wind presented to it...only that the wind can make a difference.

Once you are presented back to the wind, after the turn, you have already created the speed and decent at which you are approaching the ground, and that is when the wind will not make a difference to your approach...before that, though, when you are changing your presentation to the wind, and your angle of attack, it will make a difference.

Again, this is something to which I have given a lot of thought, and discussed at length with the people who taught me to swoop. As a matter of fact, this was one of the first lessons...in wind, for a carving turn, turn higher...for this very reason that I am trying to explain.

Would you make the same turn altitude wise if you were going into the wind, landing with no wind, or going downwind?

-S

_____________
I'm not conceited...I'm just realistic about my awesomeness...

[Hooknswoop 19]

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We are not talking about ground speed here...I totally agree with you, that the ground speed will change, but the air speed will remain the same.

Then how does the wind hit the top skin? If it hit the top skin in a dive, it would hit the nose if you were flying into it, slowing your airspeed, but it doesn’t. If it were true, an airplane would descend faster (fpm) with a head wind than wind a tail wind, all other things being equal. They don’t.

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Of course the canopy knows that wind is hitting the top skin...and the longer the top skin is presented to the wind, the more it will affect your decent. The only way, in a dive, that the canopy would not know the difference, is if the wind was coming straight up from the ground.

Not true. If it hit the top skin, it would collapse your canopy.

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That is not to say that the canopy will not dive if there is not wind presented to it...only that the wind can make a difference.

No it doesn’t, for the same reasons it doesn’t affect airspeed.

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Once you are presented back to the wind, after the turn, you have already created the speed and decent at which you are approaching the ground, and that is when the wind will not make a difference to your approach...before that, though, when you are changing your presentation to the wind, and your angle of attack, it will make a difference.

No, it won’t, it will only affect your ground speed.

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Again, this is something to which I have given a lot of thought, and discussed at length with the people who taught me to swoop. As a matter of fact, this was one of the first lessons...in wind, for a carving turn, turn higher...for this very reason that I am trying to explain.

It really doesn’t make a difference.

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Would you make the same turn altitude wise if you were going into the wind, landing with no wind, or going downwind?

Yes. I have jumped in very high winds and no wind. The wind never caused my canopy to dive more.

Derek

[SBS 0]

Here is another example, using an airplane...

In order for an airplane to go straight down, it must nose over past vertical, because if it simply turns down 90 degrees, the lift created by the wings will cause the plane to travel at an angle...

A canopy creates lift...when the canopy is pointed towards the ground, the lift is created horizontally, based on the angle of attack of the canopy. Let's call this lift that it is creating "forward energy" in this case, because we are talking about the canopy being nose over in a carve. If there is no wind, this forward energy that is being created has nothing stopping its progression, so for every measure of energy that is created, it is spent on horizontal movement over the ground. Let's say that it is 20mph of wind speed that is created. Now, if that is being created pushing against 20 miles per hour of wind, that will not change your wind speed, but it will change your flight. Your foward vector will be reduced to zero (as relating to the energy that was specifically created by that lift), but the energy is not destroyed. As we remember from Junior High, energy is not created or destroyed, only changed in form. So, where does that lift that the canopy created go? It dispurses itsself into the other vectors of the canopies flight.

When we are presented to the wind, the lift is no factor, but when we point that lift into said wind, then it is affected. The energy has to go somewhere, and there are two major vectors in the approach...forward drive and downward drive.

-S

_____________
I'm not conceited...I'm just realistic about my awesomeness...

[headoverheels 291]

You are just wrong on this. If your turn is made with the same input (risers, weight shift, toggles), you will lose the same altitude, and turn at the same rate. With higher wind, you would have to start that turn further upwind. If you start the turn at the same location, in higher wind, you would end up downwind of your intended landing point; in order to start the turn and land at the same points as in no wind, you will have to turn faster, which will make you drop more, so as to decrease the amount of time you spend in the air.

[Hooknswoop 19]

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Here is another example, using an airplane...

In order for an airplane to go straight down, it must nose over past vertical, because if it simply turns down 90 degrees, the lift created by the wings will cause the plane to travel at an angle...

A canopy creates lift...when the canopy is pointed towards the ground, the lift is created horizontally, based on the angle of attack of the canopy. Let's call this lift that it is creating "forward energy" in this case, because we are talking about the canopy being nose over in a carve. If there is no wind, this forward energy that is being created has nothing stopping its progression, so for every measure of energy that is created, it is spent on horizontal movement over the ground. Let's say that it is 20mph of wind speed that is created. Now, if that is being created pushing against 20 miles per hour of wind, that will not change your wind speed, but it will change your flight. Your foward vector will be reduced to zero (as relating to the energy that was specifically created by that lift), but the energy is not destroyed. As we remember from Junior High, energy is not created or destroyed, only changed in form. So, where does that lift that the canopy created go? It dispurses itsself into the other vectors of the canopies flight.

When we are presented to the wind, the lift is no factor, but when we point that lift into said wind, then it is affected. The energy has to go somewhere, and there are two major vectors in the approach...forward drive and downward drive.

You are thinking in terms of relative to the ground and not relative to the air mass.

First, define wind. Def n. a large body of air in rapid natural motion.

Second, how do we measure wind? With a wind meter that is fixed, usually in mph or knots. This tells us how fast the air mass is moving in relation to the ground.

Third, define airspeed, the speed at which a body moves through the air.

Airspeed is irreverent of wind speed. An aircraft, glider, or canopy flys exactly the same regardless if the air mass it is flying through is moving across the ground or not.

A perfect loop as viewed from a hot air balloon will look exactly the same to the observer in the basket in zero wind as it would in a 50 mph wind, because the balloon is staying at the same fixed point within the moving air mass, even though it is moving over the ground at 50 mph. To an observer on the ground, the loops would look different because the air mass is moving relative to the observer on the ground. The loops would be identical to the pilot of the aircraft. The wind doesn’t affect how the aircraft flys, lift vectors, or anything else, only its ground speed.

Derek

[ianmdrennan 2]

Don't feel bad if you struggle to grasp the concept right away - it's a hard one to visualize (and I don't mean this sarcastically - I've seen a lot of people struggle with it), but understand that you are incorrect. I'd highly recommend chatting to Scott Miller if he's ever in your area - he's a great teacher and is doing a lot to debunk these kinds of canopy myths.

Blue skies
Ian

Performance Designs Factory Team

[SBS 0]

I don't feel bad at all, because I am not convinced that it is your point of view that needs grasping. I am not a stupid person, and have not discussed this issue with stupid or inexperienced people. I have tried to get a hold of these people to ask them again about this issue, but unfortunately have not been able to reach them. In the event that I am incorrect in how I remember our conversations going, I do not want to say, "so and so told me this and that". But, I believe whole heartedly that I remember the conclusions as they were presented.

-S

_____________
I'm not conceited...I'm just realistic about my awesomeness...