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outrager

Real life L/D challenge at Eiger

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Yo !

All this talk about downwind 3.5 glide flights reminded me about a very nice real-life L/D challenge that's still to be conquered:

Try flying from the Mushroom (Eiger) all the way down to Grindenwald. It's a scenic and intense flight over the rolling hills. You will need to cover about 5000m distance to use all 2200m of available altitude, requiring a measly 2.6-2.7 L/D average depending on how much altitude you allow for a start and deployment. Exit altitude is 3200m, which puts it rather close to a skydive. Wind will not be a significant factor: you have to pick a quiet day to survive. Access is easy, start is safe, and LZs are bigger than most DZs :)

Plenty of attempts have been done from this exit over the years, and AFAIK the challenge remains. It should be so easy now with the new suits, eh? C'mon, do it, even at 2.9 you'll be a rock star! ;)

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Sounds like a great challenge..

Whats the furthest distance flown so far on this jump?



Not really sure. I made it to the last hill back in 2003 (4300m mark, 2050m altitude) on S3 prototype, and again to the same exact point on V2 a couple of years ago.

Endurance seems to be the key to make it over the last hill when you are low and tired. I recon if you make it over this point you make it all the way. It's hard to judge exact altitude at such a shallow angle, and you must beware of a weak pull - i almost got burned on the first attempt by using up all of the arms energy and barely extracting PC out of the pouch B|

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Are you flying a V3 already? Any attempts planned in the (your) near or far future?



Nope, and probably not this season. I took a year-long break from flying, and now got stuck in Scotland for a while. Maybe back in the fall, but won't be current and high-alt season will end by then. Otherwise i'd quietly go and rape it instead of posting here :)

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Depending on where in Scotland, you're only 3 1/2 hours on a train up down the country.

We should have a beer :)

Phoenix Fly - High performance wingsuits for skydiving and BASE
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Yo !

All this talk about downwind 3.5 glide flights reminded me about a very nice real-life L/D challenge that's still to be conquered:



....so it's only a real life challenge, if you putting you life in danger in no wind?
:ph34r:;)

How real is your life today?

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Depending on where in Scotland, you're only 3 1/2 hours on a train up down the country.

We should have a beer :)



Or make some performance flight flocks at the UKS boogie next monthB|

But that aside...a drink at UKS (or anywhere in the UK when Im also around next month) would be awesome cool..
JC
FlyLikeBrick
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At 3.52 actual and a mere 2.62 required, this must be piece of cake for Tony.



The graph is suicidal: the red point at 5k mark is impact ;) You need to allow for deployment, say at 100m AGL.

Also, suits start to fly waaaay sooner. It may be hard to scientifically plot the first few seconds, however multiple experiments show S3/V1 style suits at about 300m horizontal mark 300m below the exit point (as measured by deployment and landing/water impacts from 370m range objects ;)

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(as measured by deployment and landing/water impacts from 370m range objects ;)



Is that video still online somewhere....I recall seeing that one a long time ago. I think thats still the longest/furthest B flight in a wingsuit up to this date if Im not wrong??
JC
FlyLikeBrick
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....so it's only a real life challenge, if you putting you life in danger in no wind?



Yuri means that flying a constant glide on all your jumps, and getting the wind on top of that as a variable, is better than betting your life on the variable to begin with...
JC
FlyLikeBrick
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....so it's only a real life challenge, if you putting you life in danger in no wind?



Yuri means that flying a constant glide on all your jumps, and getting the wind on top of that as a variable, is better than betting your life on the variable to begin with...



I thought he meant that if there's any significant wind then the mountain weather will kill you...
Do you want to have an ideagasm?

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ok, I'll do it, ive never done a wingsuit base and I dont like pulling low but....hmmm maybe we can get Toby to do it, you reading this Toby, he doesnt like to pull low either, 300 m.

Heres a question, does the G/R improve with lower thicker air? it sure feels like it.
I know in a plane you gotta go higher to go faster, so, is that the same with a wingsuit?
Life is a series of wonderful opportunities,
brilliantly disguised as impossible situations.

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ok, I'll do it, ive never done a wingsuit base and I dont like pulling low but....hmmm maybe we can get Toby to do it, you reading this Toby, he doesnt like to pull low either, 300 m.



Somebody has to! ;)

You should be able to pull at 300m over the village at L/D of 2.9.

If you do fly at 3.5 you will be pulling at 600m. These numbers assume 200m of altitude wasted for a lazy start, obviously that can be done better.

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Heres a question, does the G/R improve with lower thicker air? it sure feels like it.



It does not. True airspeed (i.e. both vertical and horizontal, proportionally) does increase with altitude, so starting a suit higher up will take slightly longer. Sustained L/D will be the same at any altitude, assuming that you are indeed flying.

Google, like http://www.stolaf.edu/people/hansonr/soaring/spd2fly/densalt.htm if you want to know why in detail.

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Heres a question, does the G/R improve with lower thicker air? it sure feels like it.
I know in a plane you gotta go higher to go faster, so, is that the same with a wingsuit?



Yes...thats the same...higher you go faster, lower you go slower.
Glide-ratio is the only constant in that equation....so that one doesnt improve when you go lower (or decrease when you go higher). Only the speed at which you travel changes.
JC
FlyLikeBrick
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Actually, sustained glide ratio is slightly higher than L/D, because as you're flying into continuously denser air, you're constantly moving at slightly higher speed than true sustained speed for current layer, so effectively, you're constantly plane out.

The effect is tiny, about 1%: if you enter, for example, Vxs=100mph, Vys=40mph (L/D=2.5) in Wingsuit Equations module in Wingsuit Studio, you will see that sustained glide ratio is about 2.53.

That's nothing compared to secret method of bumping G.R. by 40% discovered by Tony in Marl. ;)

Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

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The influence of altitude wind on the glide ratio is huge! The second point is the exit and main deployment procedure...
Look on one my GPS-track.

Glide Ratio is:
In Race Zone 5285/2071=2,55.
For whole track: (619+5285+864)/(551+2071+1397)=1,68

If you see "Ground Speed Graph", you can see decreasing of my ground speed from 250+ to 150 kmh.
The "Vertical Speed" is here all time more or less constant.

If I understood "outrager", for the Eiger challenge you need glide ratio of 2,6 for whole track :ph34r:

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Awesome stuff!

Dean Potter is most likely the 1st in the world who flew from Mushroom to Grindelwald [several times in his Xcess]. From jumping with him and watching his flights, he has a very good glide at quite slow sustained speeds, both vertical and horizontal. Low wingloading allows for quick start (which doesn't require high L/D per se; max lift mode with about 45 degree angle of attack, despite having L/D of about 1.0, pulls you from the wall the fastest; then switch to higher L/D "gear" by controlling your pitch and ensuring lower AoA).

Sometimes he wouldn't be able to repeat it and I mentioned to him that it might be the headwind affecting his glide. With 2m 50s flights from the higher exit, a 20mph tailwind gives a free mile of distance, while the same headwind takes it from you. For such long flights, wind can be used creatively to do flights that would otherwise be impossible to do.

As can be seen from Wingsuit Studio simulations, longer (slower) flights allow lower L/D threshold to achieve the same goal compared to faster flights. In this example, compare two flights from the Mushroom, one is 120s long and the other 150s long. And that's without the tailwind - with tailwind the effect is even more drastic!

I'm sure we'll see lots of other amazing things done by Dean in the near future!

Yuri
Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

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Yuri, if one flew at a glide ratio of 4.5:1 , what more or less would you guess the vertical speed to be, and what would the ground speed be, and distance covered ? i guess there are variables but in very average conditions?

(pronounced G - jii is the force that makes you fly!)

Jii-Wings - no strings!

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