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heli loop not providing lift

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edt
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Re: heli loop not providing lift

Postby edt » Thu Oct 08, 2020 8:55 pm

We already have names for these loops the front heli loop is a heli down loop and the back loop is a heli kiteloop

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Re: heli loop not providing lift

Postby dice » Thu Oct 08, 2020 9:01 pm

Peter_Frank wrote:
Thu Oct 08, 2020 1:47 pm
You can not jump higher using loops, as you can not add energy thus max jump height is the same (in steady air).
The wind is a source of energy. It can always add height if there is more wind during your jump.
And the loop could (not saying it always is) maximize the use of the wind to get lift.

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Re: heli loop not providing lift

Postby Toby » Thu Oct 08, 2020 9:38 pm

edt wrote:
Thu Oct 08, 2020 8:55 pm
We already have names for these loops the front heli loop is a heli down loop and the back loop is a heli kiteloop
but a downloop loops down...this one loops on top...same with kiteloop...

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Re: heli loop not providing lift

Postby Peter_Frank » Thu Oct 08, 2020 9:57 pm

dice wrote:
Thu Oct 08, 2020 9:01 pm
Peter_Frank wrote:
Thu Oct 08, 2020 1:47 pm
You can not jump higher using loops, as you can not add energy thus max jump height is the same (in steady air).
The wind is a source of energy. It can always add height if there is more wind during your jump.
And the loop could (not saying it always is) maximize the use of the wind to get lift.

NOT true, as soon as you have left the water, you can not harvest ANY more energy at all, unless there are thermals or odd wind of course.

You can transfer your "speed" energy to height, and thats it, not possible to increment the amount of total energy, on the contrary, you will lose a bit all the time, "loss".

Thus your max jump height is fixed, and you can never get to this, but the better you are, the closer you can get to this of course :naughty:

The wind is not a source of energy when you are "in" the air, only if you are fixed to the ground or water - then it is a source of energy.

Not when flying, I am one hundred percent sure of this.

8) Peter

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Re: heli loop not providing lift

Postby edt » Thu Oct 08, 2020 10:55 pm

Until you are actually going downwind at the exact same speed as the air is you can always harvest additional kinetic energy from the difference between your speed and the speed of the air to produce height (it doesn't matter if you have the speed or the air has the speed the energy comes from the difference in speeds). We normally never go downwind at the exact same speed as the air (usually we only do that immediately after a kiteloop), so you can use theoretically use this energy to make height (though we don't do it in practice). Our wings are so inefficient compared to aircraft wings that most of our lift is produced quite near our take off when we jump so aren't normally able to harvest this kinetic energy. I can imagine a very efficient wing, some paraglider wing for instance, that lifts lightly off the water from a dead stop and continues to glide up for quite a while.

I agree of course that there is a fixed amount of total energy available when you jump you can't make something out of nothing and you can't increase it while in the air.

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Re: heli loop not providing lift

Postby pākihiroa » Fri Oct 09, 2020 12:11 am

What edt says. It is the speed differential that matters. Definitely when a decent gust comes along while you are in the air you can get a (perceived) boost.

Also, think in three dimensions. Presumably there can be a vertical component to the gust. Watch a seagull hover.

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Re: heli loop not providing lift

Postby Papiloko » Fri Oct 09, 2020 2:34 am

Leon van Bergen wrote:
Thu Oct 08, 2020 9:54 am
Check 2:30, 3 Heliloops and he almost double the hangtime (14sec).

''heliloops not increase overall hangtime, not possible'' ???

for the original author of this topic look how when he loops three times at 2.30 he is not fishpoling the bar or having the bar all the way pulled in... otherwise he would fall faster like what you are experiencing.

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Re: heli loop not providing lift

Postby Peter_Frank » Fri Oct 09, 2020 7:28 am

edt wrote:
Thu Oct 08, 2020 10:55 pm
Until you are actually going downwind at the exact same speed as the air is you can always harvest additional kinetic energy from the difference between your speed and the speed of the air to produce height (it doesn't matter if you have the speed or the air has the speed the energy comes from the difference in speeds). We normally never go downwind at the exact same speed as the air (usually we only do that immediately after a kiteloop), so you can use theoretically use this energy to make height (though we don't do it in practice). Our wings are so inefficient compared to aircraft wings that most of our lift is produced quite near our take off when we jump so aren't normally able to harvest this kinetic energy. I can imagine a very efficient wing, some paraglider wing for instance, that lifts lightly off the water from a dead stop and continues to glide up for quite a while.

I agree of course that there is a fixed amount of total energy available when you jump you can't make something out of nothing and you can't increase it while in the air.

You are twisting the words wrongly edt.

We say exactly the same though :D

My point is you can NOT harvest energy once you have left the water.

Yes, you can transfer energy, kinetic to potential and reverse - but this has got nothing to do with "harvesting" energy.
The amount of height (energy) you gain, is lost in speed (relative to the air) - meaning you dont harvest any energy.

A wind turbine can harvest energy, because you constantly add energy from the wind (relative to the ground).

But a glider or a kite no matter if 100 % efficient, can not harvest energy if in stable air, also only convert energy, meaning you dont harvest energy whatsoever.

For energy to be harvested, you need to have external energy added, at least for a short period.
This is not the case when you are airborne in stable wind.
No energy added, so no energy can be harvested :-?


The autogyro effect though, that heliloops can add hangtime (but not energy nor height), is most likely correct to some extent, yes, and interesting.

8) Peter

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Re: heli loop not providing lift

Postby Peter_Frank » Fri Oct 09, 2020 7:35 am

pākihiroa wrote:
Fri Oct 09, 2020 12:11 am
What edt says. It is the speed differential that matters. Definitely when a decent gust comes along while you are in the air you can get a (perceived) boost.

Also, think in three dimensions. Presumably there can be a vertical component to the gust. Watch a seagull hover.

No it is not.

The speed differential is simply your present energy you are just converting to another type of energy (height, well height and speed actually).

You dont harvest energy.

A gust is another matter, and here we agree, you ADD energy from outside, and can harvest energy.
The same if you got a thermal updraft, or ridge updraft (the ones seagulls use, also on waves), then you can harvest total energy.

But that was not the topic of this side topic, it was about whether you can harvest energy when doing a jump in clean air.
You can not, not even if it is nuking wind :D

8) Peter

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Re: heli loop not providing lift

Postby AndersP » Fri Oct 09, 2020 7:45 am

The heliloop creates kitespeed. That temporary overspeed can be used to make the landing softer by pulling the steering lines after the the heliloops.

It's the principle that paragliders use when they increase the speed by spiraling downwards before doing for an example a wingover.

First increase the speed by turning the kite, the use the overspeed to create a temporay lift.

It is almost the same as you do when boosting.
Create as much kitespeed as you can, then use the speed to get lift.


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