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Getting Big to get back from a long spot????

 

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azureriders  (D 28830)

Jun 22, 2010, 7:15 PM
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Getting Big to get back from a long spot???? Can't Post

This past weekend we had a couple professional canopy coaches out working with some of our novice jumpers. I was working and not involved but everything I saw was great. They spent a lot of time and effort and were even looking out for others that were not taking the course and giving free advice. A really nice job I thought.

After they were gone I asked a couple of people taking the course how their long spot exercise went. I was told how well that getting big worked as the wind was hitting them in the back and pushing them back. At first I thought it was simply misunderstood information but after questioning a couple others it was obvious that is what they were taught: get big if the wind is hitting your back, get small if the wind is hitting your face.

Your thoughts and discusion ??




My thoughts:

Your air speed is going to be the same regardless of wind direction given all other factors equal. If getting smaller helps you move faster horizontally with a head wind, it will also help you move faster horizontally with a tail wind. Although ground speed is what is going to bring you back, a faster air speed is going give you a faster ground speed in either situation.

While under a properly functioning ram air sport skydiving canopy in half brakes (which is the way they were told to fly to get back, which is fine to me and not the point of this conversation) you will have a positive air speed and therefore the relative wind will always be in your face and there will always be a burble behind and above you and the wind will never be able to hit you in the back as you will always be out running it by exactly your air speed.

Getting big is only going to increase drag and therefore slows both your air speed as well as your ground speed. It is also going to increase you skydiver/parachute drag ratio which is going to push your body back further under the parachute increasing your angle of influence and therefore cause your canopy to fly steeper towards the ground. None of which is going to help you get back from a long spot.




Everyone’s opinion is welcome of course. I am an Instructor questioning a canopy coach. It would be good to hear from others of the same. I am also very interested in not only opinion, but the verbiage used by any one in canopy design or CReW.


(This post was edited by azureriders on Jun 22, 2010, 7:51 PM)


skydiverkeith

Jun 22, 2010, 7:27 PM
Post #2 of 81 (1766 views)
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Re: [azureriders] Getting Big to get back from a long spot???? [In reply to] Can't Post

I can tell you that geting small when flying into the wind helps a lot. As for the other way around, the physics suggest it would work, but I have no personal experience.


kallend  (D 23151)

Jun 22, 2010, 7:28 PM
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Re: [azureriders] Getting Big to get back from a long spot???? [In reply to] Can't Post

In reply to:
This past weekend we had a couple professional canopy coaches out working with some of our novice jumpers. I was working and not involved but everything I saw was great. They spent a lot of time and effort and were even looking out for others that were not taking the course and giving free advice. A really nice job don’t I thought.

After they were gone I asked a couple of people taking the course how their long spot exercise went. I was told how well that getting big worked as the wind was hitting them in the back and pushing them back. At first I thought it was simply misunderstood information but after questioning a couple others it was obvious that is what they were taught: get big if the wind is hitting your back, get small if the wind is hitting your face.

Your thoughts and discusion ??




My thoughts:

Your air speed is going to be the same regardless of wind direction given all other factors equal. If getting smaller helps you move faster horizontally with a head wind, it will also help you move faster horizontally with a tail wind. Although ground speed is what is going to bring you back, a faster air speed is going give you a faster ground speed in either situation.

While under a properly functioning ram air sport skydiving canopy in half brakes (which is the way they were told to fly to get back, which is fine to me and not the point of this conversation) you will have a positive air speed and therefore the relative wind will always be in your face and there will always be a burble behind and above you and the wind will never be able to hit you in the back as you will always be out running it by exactly your air speed.

Getting big is only going to increase drag and therefore slows both your air speed as well as your ground speed. It is also going to increase you skydiver/parachute drag ratio which is going to push your body back further under the parachute increasing your angle of influence and therefore cause your canopy to fly steeper towards the ground. None of which is going to help you get back from a long spot.




Everyone’s opinion is welcome of course. I am an Instructor questioning a canopy coach. It would be good to hear from others of the same. I am also very interested in not only opinion, but the verbiage used by any one in canopy design or CReW.

Getting big increases drag, which increases your descent rate and slightly reduces forward speed. Doesn't matter if you are going into the wind or downwind. If you want to go farther, you do not want to get big.


airtwardo  (D License)

Jun 22, 2010, 7:52 PM
Post #4 of 81 (1732 views)
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Re: [kallend] Getting Big to get back from a long spot???? [In reply to] Can't Post

Getting big increases drag, which increases your descent rate and slightly reduces forward speed. Doesn't matter if you are going into the wind or downwind. If you want to go farther, you do not want to get big.
I wonder what the actual increase of distance gained would be for a given altitude of say 2500' ?

Not that it would ever really matter to me...I'm pretty much the same size with or against the wind. Wink


davelepka  (D 21448)

Jun 22, 2010, 8:30 PM
Post #5 of 81 (1714 views)
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Re: [azureriders] Getting Big to get back from a long spot???? [In reply to] Can't Post

 
You are 100% correct in your assumption. Reducing drag increases airspeed, end of story. Make your canopy ride as long as possible (half brakes, or some other input to reduce the descent rate), and go as fast as you can during that canopy ride (reducing drag as much as possible).

When you say canopy coaches, you're saying that there was more then one of them, and they were all in agreement about 'getting big'? Very surprising to hear.


pilotdave  (D License)

Jun 22, 2010, 8:32 PM
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Re: [skydiverkeith] Getting Big to get back from a long spot???? [In reply to] Can't Post

Quote:
the physics suggest it would work, but I have no personal experience.

We're always* flying into the RELATIVE wind. Getting big never helps. Hard to believe anyone is teaching a canopy course that can't grasp that concept.

*ok, not ALWAYS... see attached. Smile

Dave


(This post was edited by pilotdave on Jun 22, 2010, 8:34 PM)
Attachments: flying backwards.jpg (22.7 KB)


pchapman  (D 1014)

Jun 22, 2010, 8:34 PM
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Re: [azureriders] Getting Big to get back from a long spot???? [In reply to] Can't Post

If the course participants were indeed being taught to get big to use the tail wind, the instructors have a fundamentally flawed concept of how a canopy flies.

The error is a clear one, not mitigated by any significant differences of opinion in the community, or any imprecision of the terminology used in the sport.

Their mistaken understanding is likely to cause other major errors in teaching about canopy flight.

This would be true even if they are otherwise skilled canopy pilots and instructors.


azureriders  (D 28830)

Jun 22, 2010, 8:47 PM
Post #8 of 81 (1699 views)
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Re: [pchapman] Getting Big to get back from a long spot???? [In reply to] Can't Post

In reply to:
If the course participants were indeed being taught to get big to use the tail wind, the instructors have a fundamentally flawed concept of how a canopy flies.

The error is a clear one, not mitigated by any significant differences of opinion in the community, or any imprecision of the terminology used in the sport.

Their mistaken understanding is likely to cause other major errors in teaching about canopy flight.

This would be true even if they are otherwise skilled canopy pilots and instructors.

I agree with every bit of that, but before we tar and feather them, let me clairify something that I may have mis worded in my original post. There is no doubt what so ever that what I posted is what the participants took away from the course. However, most Instructors will agree that you can teach the same class over and over and at some point a whole class room of people will misunderstand the same point. I normally chalk it up to them asking each other questions when the teacher is out.

anyway, point is I did not hear this info being taught, I just know what the class took home in their head.


pchapman  (D 1014)

Jun 22, 2010, 8:53 PM
Post #9 of 81 (1689 views)
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Re: [azureriders] Getting Big to get back from a long spot???? [In reply to] Can't Post

In reply to:
anyway, point is I did not hear this info being taught, I just know what the class took home in their head.

Good point. I've taught a few little canopy courses myself and there have been times when someone came away with an idea that certainly wasn't what I was trying to teach. Misunderstandings do happen when trying to teach a lot in a short time.


thedude325  (A License)

Jun 22, 2010, 9:04 PM
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Re: [azureriders] Getting Big to get back from a long spot???? [In reply to] Can't Post

In reply to:
It is also going to increase you skydiver/parachute drag ratio which is going to push your body back further under the parachute increasing your angle of influence and therefore cause your canopy to fly steeper towards the ground.

That was the first thing I thought of when I read this. If you increase the area of the pilot without doing anything to the canopy, the wind will push the pilot farther forward, causing the centroid to move farther forward. Increasing the angle of attack.

Attached is an excerpt from Brian Germain's sizing chart.
Attachments: angle of attack.JPG (41.0 KB)


pilotdave  (D License)

Jun 22, 2010, 9:36 PM
Post #11 of 81 (1655 views)
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Re: [thedude325] Getting Big to get back from a long spot???? [In reply to] Can't Post

In reply to:
In reply to:
It is also going to increase you skydiver/parachute drag ratio which is going to push your body back further under the parachute increasing your angle of influence and therefore cause your canopy to fly steeper towards the ground.

That was the first thing I thought of when I read this. If you increase the area of the pilot without doing anything to the canopy, the wind will push the pilot farther forward, causing the centroid to move farther forward. Increasing the angle of attack.

The opposite will happen (though in ordinary conditions I don't think it would make a noticeable difference), as it says in what you quoted above. When your canopy is flying through the air, a tailwind has no affect on how the canopy flies in relation to the air. Getting big with a tailwind or with a headwind will have the exact same effect. You will increase your drag, slowing you down. Your body will move back in relation to the canopy (usually very slightly) causing the canopy to steepen.

We cannot use our bodies like sails. It doesn't make sense.

Dave


thedude325  (A License)

Jun 22, 2010, 10:08 PM
Post #12 of 81 (1641 views)
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Re: [pilotdave] Getting Big to get back from a long spot???? [In reply to] Can't Post

In reply to:
In reply to:
In reply to:
It is also going to increase you skydiver/parachute drag ratio which is going to push your body back further under the parachute increasing your angle of influence and therefore cause your canopy to fly steeper towards the ground.

That was the first thing I thought of when I read this. If you increase the area of the pilot without doing anything to the canopy, the wind will push the pilot farther forward, causing the centroid to move farther forward. Increasing the angle of attack.

The opposite will happen (though in ordinary conditions I don't think it would make a noticeable difference), as it says in what you quoted above. When your canopy is flying through the air, a tailwind has no affect on how the canopy flies in relation to the air. Getting big with a tailwind or with a headwind will have the exact same effect. You will increase your drag, slowing you down. Your body will move back in relation to the canopy (usually very slightly) causing the canopy to steepen.

We cannot use our bodies like sails. It doesn't make sense.

Dave

Gotcha. Interesting stuff.


riggerpaul  (D 28098)

Jun 23, 2010, 3:49 AM
Post #13 of 81 (1585 views)
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Re: [azureriders] Getting Big to get back from a long spot???? [In reply to] Can't Post

In reply to:
In reply to:
If the course participants were indeed being taught to get big to use the tail wind, the instructors have a fundamentally flawed concept of how a canopy flies.

The error is a clear one, not mitigated by any significant differences of opinion in the community, or any imprecision of the terminology used in the sport.

Their mistaken understanding is likely to cause other major errors in teaching about canopy flight.

This would be true even if they are otherwise skilled canopy pilots and instructors.

I agree with every bit of that, but before we tar and feather them, let me clairify something that I may have mis worded in my original post. There is no doubt what so ever that what I posted is what the participants took away from the course. However, most Instructors will agree that you can teach the same class over and over and at some point a whole class room of people will misunderstand the same point. I normally chalk it up to them asking each other questions when the teacher is out.

anyway, point is I did not hear this info being taught, I just know what the class took home in their head.

Now you are confusing me.

In your original post, you said you confirmed with them their intent to say that getting big for a tail wind would help come back from the long spot.

Did they say that or didn't they?


azureriders  (D 28830)

Jun 23, 2010, 6:20 AM
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Re: [riggerpaul] Getting Big to get back from a long spot???? [In reply to] Can't Post

I am positive that three novice skydivers left that day with the concept of getting big to get back. All three were very adimant that that is what they were taught. I have not talked to the actual coaches nor did I hear the information being taught. I am inclined to believe this information was indeed taught, however to be fair it is possible that the information was simply misunderstood by the three participants.

You are right, my original post did not leave room for honest misunderstanding. My apologies. Still a good discusion.


riggerpaul  (D 28098)

Jun 23, 2010, 6:27 AM
Post #15 of 81 (1526 views)
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Re: [azureriders] Getting Big to get back from a long spot???? [In reply to] Can't Post

In reply to:
I am positive that three novice skydivers left that day with the concept of getting big to get back. All three were very adimant that that is what they were taught. I have not talked to the actual coaches nor did I hear the information being taught. I am inclined to believe this information was indeed taught, however to be fair it is possible that the information was simply misunderstood by the three participants.

You are right, my original post did not leave room for honest misunderstanding. My apologies. Still a good discusion.

And my apology to you, too.

I thought you said that you had confirmed it with the instructors.

But you actually said you talked to the students.

When I read the post a third time, I noticed my own error.


azureriders  (D 28830)

Jun 23, 2010, 6:44 AM
Post #16 of 81 (1516 views)
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Re: [riggerpaul] Getting Big to get back from a long spot???? [In reply to] Can't Post

In reply to:
When I read the post a third time, I noticed my own error.

We all make a few of those, no biggyCool


rehmwa  (D 12816)

Jun 23, 2010, 6:54 AM
Post #17 of 81 (1501 views)
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Re: [azureriders] Getting Big to get back from a long spot???? [In reply to] Can't Post

sounds like poor delivery of information - it's up to the coaches to be correct and clear

1 - getting big only increases drag - the coaches are not clear in communicating that canopy aerodynamics reference the air around them and not the ground

2 - half brakes to get back - the coaches were not clear in communicating that canopies have several inputs - while half brakes is good for many canopies, rear risers might be smarter for other models, etc etc

do you know if they mentioned spreading the risers (loosening the chest strap is an example) - giving the canopy a flatter profile increases its efficiency - that's a big deal for some canopies


(This post was edited by rehmwa on Jun 23, 2010, 8:05 AM)


DocPop  (C License)

Jun 23, 2010, 7:43 AM
Post #18 of 81 (1465 views)
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Re: Getting Big to get back from a long spot???? [In reply to] Can't Post

Could you please let us know which canopy course this was? Who were the instructors?

My guess is that if it was multiple instructors, it was probably Flight-1, am I right?


ChrisL  (C 35323)

Jun 23, 2010, 7:46 AM
Post #19 of 81 (1463 views)
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Re: [azureriders] Getting Big to get back from a long spot???? [In reply to] Can't Post

Ultimately, it sounds like they were only told to do the wrong thing in a circumstance that will never happen, so the belief will not likely result in anyone coming to grief.

The wind will always be in their face so they will always get small.

Perhaps...


azureriders  (D 28830)

Jun 23, 2010, 8:19 AM
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Re: [DocPop] Getting Big to get back from a long spot???? [In reply to] Can't Post

In reply to:
Could you please let us know which canopy course this was? Who were the instructors?

My guess is that if it was multiple instructors, it was probably Flight-1, am I right?

There are many skydivers, including canopy competitors and teams who teach canopy courses. Using multiple instructors is fairly common. In other words, your odds of just guessing who this was based on the fact they use multiple instructors are very slim. No this was not Flight-1.

I would not hash and bash on the instructors unless I actually heard the mis information being taught. These guys did a lot of good things while they were there and the point of this thread was not to flame them. It is still possible that this information was just misunderstood. I was not worried to much about that aspect, but I think I will follow up on this and find out.

I just wanted to bring up what I heard going arond for discusion so that hopefully some would learn from it.


pchapman  (D 1014)

Jun 23, 2010, 8:33 AM
Post #21 of 81 (1431 views)
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Re: [ChrisL] Getting Big to get back from a long spot???? [In reply to] Can't Post

In reply to:
Ultimately, it sounds like they were only told to do the wrong thing in a circumstance that will never happen, so the belief will not likely result in anyone coming to grief.

No, the point was that "wind at their back" was being understood as "flying with a tail wind", so it is something the jumpers will do a lot.


rehmwa  (D 12816)

Jun 23, 2010, 8:49 AM
Post #22 of 81 (1412 views)
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Re: [pchapman] Getting Big to get back from a long spot???? [In reply to] Can't Post

In reply to:
In reply to:
Ultimately, it sounds like they were only told to do the wrong thing in a circumstance that will never happen, so the belief will not likely result in anyone coming to grief.

No, the point was that "wind at their back" was being understood as "flying with a tail wind", so it is something the jumpers will do a lot.

this also leads to incorrect assumptions like - front risers into a wind will cause the nose to fold, etc etc etc - it's basic aero referencing. It should be taught correctly.


elightle  (D 5966)

Jun 23, 2010, 9:36 AM
Post #23 of 81 (1380 views)
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Re: [azureriders] Getting Big to get back from a long spot???? [In reply to] Can't Post

I was taught to use rear risers when flying into the wind from a long spot, and to use half brakes when the wind is at my back.


rehmwa  (D 12816)

Jun 23, 2010, 9:45 AM
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Re: [elightle] Getting Big to get back from a long spot???? [In reply to] Can't Post

weren't you also taught to rake up the peas after each crash, er, landing? and to check your apex for a sky view?Tongue


airtwardo  (D License)

Jun 23, 2010, 9:48 AM
Post #25 of 81 (1370 views)
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Re: [rehmwa] Getting Big to get back from a long spot???? [In reply to] Can't Post

In reply to:
weren't you also taught to rake up the peas after each crash, er, landing? and to check your apex for a sky view?Tongue

No....sawdust, peas are too expensive and they don't stick to ya when yer all sweaty! Sly


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