Choosing initiation altitude at different dropzones

[sabrepilot25 0]

Okay these maybe some dumb questions but hopefully someone can help me understand. I have been doing 270 landings for a short while. What confuses me is this: How do good swoopers find a good final turn altitude when they go to a different dropzone at a different elevation on their first jump? I have only ever worked out my turn altitude by starting off turning high and then i knock off 10 feet for each jump until i find a good altitude. However I have seen people turn up to a dropzone they have never jumped at before, that is at a completely different elevation to what they are used to and they can pull off a perfect 270 swoop on their first jump. I have also seen a friend jump a canopy he has never jumped before and land a perfect 270 on the first jump.

If I was to turn 660 feet for my final 270 turn at a 0 elevation dropzone, what sort of height do you think i'd need to turn at if i went to a 3000 foot elevation DZ? I know this last questions a long shot and it would be impossible to be specific, i'm just looking for a rough idea. Thanks

[jacketsdb23 45]

The best thing to do with major elevation changes is to start all over. Doing 270's on the first jump with a new canopy or at a new DZ is a bad idea at best.

I would start all over with 90's. Do some 270's high and check your altitude loss just like you did when you started doing 270's at your home DZ.

Be safe!

Losers make excuses, Winners make it happen
God is Good
Beer is Great
Swoopers are crazy.

[JSE 1]

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I have been doing 270 landings for a short while.

That might have something to do with it. Marcel's advice is good. After you've been doing 270s for longer you will develop a better sense of the sight picture for the turn.
It probably isn't hard for you to do 90s at a new dz or on a new canopy. But at one point it was challenging to do a good 90 on any canopy anywhere.

A lot of times I will estimate how much to raise or lower my turn and then control the turn rate to compensate for being high or low as I come around. When in doubt (and even when there is no doubt) start high and air on the side of caution.

[sabrepilot25 0]

Thanks guys, i appreciate the advice, I'm still kind of curious as to how much difference DZ elevation should make to the initiation altitude. Again I know a specific answer isn't possible, but out of curiosity JSE what turn do you do when you land (degrees)?, what altitude at your home DZ and how do you estimate the height to turn at a different DZ apart from doing the turn up high first? Is the difference usually a matter of 10 feet+ or is it more like 100feet+. I'm just confused cos if guys like jay moldeski turn up to a competition at a DZ they have never jumped at before, would he really start with 90s (before the competition of course) or smaller turns than the 450 and work his way up? Thankyou

[BMFin 0]

I dont know what type of canopy you jump, but it sounds like it has a quite positive recovery arc. (in other words youll end up high if you start too high)

I would say it is someworth less essential to initiate a turn at a precise altitude if you are flying a canopy like velocity that doesnt have such a positive recovery arc. Therefore you may keep it diving a bit longer if you need to. And therefore you wont have to worry so much wheter your initiation altitude is +-100ft

btw. Atmospheric pressure does vary on sea level also. Ofcourse the scale of variation isnt more than a few hundred meters.

[chuckakers 370]

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I have only ever worked out my turn altitude by starting off turning high and then i knock off 10 feet for each jump until i find a good altitude.

Calibrated eyeballs?

Chuck Akers
D-10855
Houston, TX

[AggieDave 6]

There's a formula for it:

x = {q + [q2 + (r-p2)3]1/2}1/3 + {q - [q2 + (r-p2)3]1/2}1/3 + p

When you get your pro-card we'll tell you what the variables stand for.


Ok, seriously, its something that you learn by experience. It also helps to ask other jumpers at the DZ what they do or recommend. For instance, The last two times I was able to visit Mile-Hi, I bumped my turn about 100ft. Back in August I bumped it 200ft then brought it down to about 100ft over the course of a couple of practice jumps.

I decided on 200ft, as it *felt* about right to be safe with the altitude and after talking to a couple of other competitors.

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[kameraflyr 0]

Is it printed on the back somewhere? Because I still haven't gotten mine.... Damnit, I started swooping because I was told there was no math....First I have to deal with GW taking the podium at world, and now math....That's it I quit.

[hparrish 0]

I think its pretty common knowledge that higher elevation DZs require extra altitude. I know when I'm at Lost Prarie or Tahoe I bump my initiation height up, than when I'm in NC.

I don't think there are set numbers such a 750 feet at 0 Feet Elevation and 1100 feet at 5000 feet elevation. I think that is determined by the individual pilot and the wing they are flying.

[dzromeo 0]

Can't believe in this entire thread, noone has mentioned density altitude.

The truth is that when flying anything, whether it be a rigid wing airframe, or a low performance parachute, the *actual* altitude MSL of the landing area doesn't matter in the least. What matters is the density altitude, or, how thick the landing area air is. If you're visiting a dropzone with a 10 ft. MSL elevation, but its extremely hot that day and a low pressure system is just arriving, the density altitude could change dramatically over the course of the day and require you to begin landing sequence initiation significantly higher AGL than you did on the first load.

This is an adaptation that comes with a great deal of knowledge and experience. The OP referred to skilled pilots that make a 270 degree front riser dive on final during their first landing at an unfamiliar DZ. One thing to take into account is that these pilots make constant, minor trim adjustments during their approach and landing. They notice the increase or decrease in dive rate and modify the approach as they're making it in order to compensate.

Someday, when we're all grown up, we'll be able to do it too. :)

Blue skies, stay safe.

-Alex

Plan the dive, dive the plan.

[frost 1]

well said.

[dharma1976 0]

wow...

you are wise beyond your jump numbers grasshopper

D

http://www.skyjunky.com

CSpenceFLY - I can't believe the number of people willing to bet their life on someone else doing the right thing.

[nbblood 0]

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Ok, seriously, its something that you learn by experience. It also helps to ask other jumpers at the DZ what they do or recommend. For instance, The last two times I was able to visit Mile-Hi, I bumped my turn about 100ft. Back in August I bumped it 200ft then brought it down to about 100ft over the course of a couple of practice jumps.

I decided on 200ft, as it *felt* about right to be safe with the altitude and after talking to a couple of other competitors.

Dave,
Just to clarify, you're talking about 100 feet and 200 feet more than you normally initiate the turn, not initiating the turn at 100 feet or 200 feet, right??

No, I'm not trying to be a smart ass, I just don't want to hear about someone initiating a 270 at a hundred or two hundred feet. And, yes, I already know the answer......just clarifying.

Blues,
Nathan

If you wait 'til the last minute, it'll only take a minute.

[BMFin 0]

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Can't believe in this entire thread, noone has mentioned density altitude.

I believe I mentioned this in my post ?

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btw. Atmospheric pressure does vary on sea level also. Ofcourse the scale of variation isnt more than a few hundred meters.

But ofcourse its not too bad to mention it again.

[AggieDave 6]

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Just to clarify, you're talking about 100 feet and 200 feet more than you normally initiate the turn, not initiating the turn at 100 feet or 200 feet, right??

Right.

I was closer to 1000ft then 100 or 200ft off the deck.

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[Mikko 0]

With experience, you know pretty well how much the weather and altitude affects your initiation point. (because having skydived on such a many dropzones before) With experience, you are also able to find out if you turned too high or too low in the middle of the turn.(because of having been both too low and too high so many times before) With experience, you are also able to adjust your turn better when you know that you're too high or low. (because of having corrected your own misjudgements so many times during the turn)

With all that experience you can get it right on the first one. Or at least miss it so little that no one notices.

[AggieDave 6]

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Or at least miss it so little that no one notices.

That is one of the things that make the top pros (Ian excluded of course), so amazing to watch. They show up to a random spot, toss out a turn and make it look very easy.

--"When I die, may I be surrounded by scattered chrome and burning gasoline."