Wind Tunnels’ Long Term Effect on Competition

[ltdiver 3]

Why don't you tell him the one about the manhole covers?




(I'd post a workable direct link to help ya out, but it seems that the old link is dead.)

ltdiver

Don't tell me the sky's the limit when there are footprints on the moon

[kallend 1,623]

Quote

Quote

What do you mean by "real lift"? Lift is certainly developed in the sense used in aerodynamics. I am not aware of another definition.

More than a negligible amount of lift.

OK, lets assume someone can track at 1:1 glide ratio (I believe this is possible for good trackers. Derek (Hooknswoop) has posted data indicating he has done this.

If the skydiver + rig has a mass of 100kg (just as an example) then the resolved force perpendicular to the line of flight (lift) will be 100*9.81*cos(45) Newtons (= 696N, or about 155 pounds force) which is not negligible.

...

The only sure way to survive a canopy collision is not to have one.

[Nick 0]

I think the discussion here is not whether one can track in the tunnel but whether one can simulate a track. After all one does not actually freefall in the tunnel but simulates the freefall!

After being in the tunnel with Thomas it became apparent to me that there are a lot of things one can do things that I'd never thought possible, such as launch formations and produce enough forward movement to simulate an effective tracking position.

Remember the tunnel is a simulator just the save as pilots use.

Nick
Gravity- It's not just a good idea, it's the LAW!

[kallend 1,623]

Quote

I think the discussion here is not whether one can track in the tunnel but whether one can simulate a track. After all one does not actually freefall in the tunnel but simulates the freefall!

After being in the tunnel with Thomas it became apparent to me that there are a lot of things one can do things that I'd never thought possible, such as launch formations and produce enough forward movement to simulate an effective tracking position.

Remember the tunnel is a simulator just the save as pilots use.

How can you possbly simulate something that requires a lot of horizontal speed? Good trackers achieve 60 -80mph horizontally, and this velocity is essential to producing the lift. Vertical velocity drops to maybe 80mph so they'd have to turn down the tunnel speed to accommodate that too.

A body position corresponding to a good track would put your head through the tunnel wall within 1/2 second or so.

The free stream direction in a good track is at about 45 degrees to the vertical, and body position has to be optimized for that angle. You just can't simulate that in a vertical airflow, IMO.

...

The only sure way to survive a canopy collision is not to have one.

[Nick 0]

What I'm saying is that you can simulate the body position while having somebody pushing against you.

As for your head being put through the wall would you have enough time to accelerate to the sort of speed required to do this in a tunnel?

I'm not scientist but I do know that the experience I gained in the tunnel will help my freefall no end, even if it has just taught me more about how my body flies.

Nick
Gravity- It's not just a good idea, it's the LAW!

[quade 3]

Quote

After being in the tunnel with Thomas it became apparent to me that there are a lot of things one can do things that I'd never thought possible, such as launch formations and produce enough forward movement to simulate an effective tracking position.

I've asked for this before and nobody has ever come through for me. Could you PLEASE point me, email me, whatever -- some video of people launching formations in a tunnel.

I simply can not picture how this can be done and I'd be -very- interested in seeing some actual data. Like taking some ab inito tunnel rats, teaching them to "launch" 4-way pieces in a tunnel and then watching them launch the same pieces out of an actual Twin Otter.

As far as I have it figured, there's at least three fairly basic freefall skills that can't even begin to be accurately simulated in a wind tunnel: exits, 10-way/Big-way style dive/float and tracking.

If a person wants to say they can quickly transition from standing to belly to earth in the tunnel, that's one thing, but exits? Where the heck is the door? How do you do a head jam? How do you simulate the uneven airstream between inside and outside of the aircraft?

Maybe it's fun and saves time going from standing to BTE, but it's not an exit. I think even ThomasHuges in this thread pretty much admitted that.

quade -
The World's Most Boring Skydiver

[Ron 7]

Quote

I've asked for this before and nobody has ever come through for me. Could you PLEASE point me, email me, whatever -- some video of people launching formations in a tunnel.

I simply can not picture how this can be done and I'd be -very- interested in seeing some actual data. Like taking some ab inito tunnel rats, teaching them to "launch" 4-way pieces in a tunnel and then watching them launch the same pieces out of an actual Twin Otter.

Quade,

We do it. You can launch a two way in the tunnel from the door.

A 4way you walk in, stand on the net, and give a count. At the "Go" you transition from standing with grips to flying.

Quote

If a person wants to say they can quickly transition from standing to belly to earth in the tunnel, that's one thing, but exits? Where the heck is the door? How do you do a head jam? How do you simulate the uneven airstream between inside and outside of the aircraft?

You can't, but it does *simulate* (which is the whole deal with a tunnel) going from not flying to flying and helps reduce the amount of hold time from exit to break.

You can't practice exits in the tunnel, and you can't track in the tunnel...You *can* practice the body position need to track (although you will not know if you have the correct position since you will not be able to gain the horizontal speed needed to gain lift). And you can practice the not skydiving/suddenly skydiving part of an exit in the tunnel.

Both can be good, but both also are not the same thing as it is in freefall.

Remember while you are flying your body in a wind tunnel, you are not skydiving, or freefalling and that means that somethings will not be able to be practiced.

Ron

"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334

[billvon 2,400]

>After being in the tunnel with Thomas it became apparent to me
>that there are a lot of things one can do things that I'd never
> thought possible, such as launch formations . . .

While this is definitely possible, it can be a dangerous thing to do. If you try to launch an exit out of an otter the same way you launch one in a tunnel you'll be 90 degrees off in your presentation. You can overcome this if you remember, of course, but it can be a bad habit to get in to.

[rehmwa 2]

Quote

If you try to launch an exit out of an otter the same way you launch one in a tunnel .

??You mean everyone start at the same time and launch the formation into the relative wind??

I can see why that would be a bad learning experience.

What I mean here is you can get anything out of even a simulator if that's your goal. (Even with the edge effects, non-(quasi)infinite boundaries, baffling from person(s) off level, etc......)

Still, great supplemental tool. Still, I'd rather practice exits off the plane and the basics in the tunnel. Still having a hard time with the boundary effects for piece practice and anything bigger than 3.....

...
Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants

[billdo 0]

Quote

***As far as I have it figured, there's at least three fairly basic freefall skills that can't even begin to be accurately simulated in a wind tunnel: exits, 10-way/Big-way style dive/float and tracking.

Can you wear a rig in a tunnel and deploy it? What happens when people do that?

Sorry, being a smartass.

[Nick 0]

Quote

Can you wear a rig in a tunnel and deploy it? What happens when people do that?

I'm sure that the people who run the tunnel would get very upset as I'm sure it wouldn't do the fans much good, wouldn't do the canopy much good either!!!

Nick
Gravity- It's not just a good idea, it's the LAW!

[kallend 1,623]

Quote

Can you wear a rig in a tunnel and deploy it? What happens when people do that?

If you try it, can I watch?

...

The only sure way to survive a canopy collision is not to have one.

[Ron 7]

Quote

Can you wear a rig in a tunnel and deploy it? What happens when people do that?

I know that they have worn rigs in the Ft.Bragg tunnel.

I have heard storys about someone trying to deply one....It was much less of an issue than you would think. They have a grateing that it stuck to...(Or so I am told.)

Now an outdoor tunnel might be ugly.

"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334

[Samurai136 0]

Quote

Now an outdoor tunnel might be ugly.

That would be interesting.

"See. They do go up when they deploy the parachute!"

Ken

"Buttons aren't toys." - Trillian
Ken

[ThomasHughes 0]

I've asked for this before and nobody has ever come through for me. Could you PLEASE point me, email me, whatever -- some video of people launching formations in a tunnel.

I simply can not picture how this can be done and I'd be -very- interested in seeing some actual data. Like taking some ab inito tunnel rats, teaching
Maybe it's fun and saves time going from standing to BTE, but it's not an exit. I think even ThomasHuges in this thread pretty much admitted that.

[ThomasHughes 0]

Quote

Rage in 2000 Nats did a 15.3 avg in intermediate with 100 jumps together exits were all fine for the last 75 jumps together. some of the people onthe team had less than 500 jumps, one had less than 200 how would you explain that. besides lots of time in the tunnel? Which they all had.

Exits and entrys to the tunnel are all relevant just on a different angle.

• Quote

[Ron 7]

What are you replying to?

Quote

Rage in 2000 Nats did a 15.3 avg in intermediate with 100 jumps together exits were all fine for the last 75 jumps together. some of the people onthe team had less than 500 jumps, one had less than 200 how would you explain that. besides lots of time in the tunnel? Which they all had.

Exits and entrys to the tunnel are all relevant just on a different angle.

How do I explain what?

And I know who Rage was. One of my old teammates was Glenn.

"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334

[rehmwa 2]

Looks like he's agreeing with you and providing another good example..... The question was likely still in responding to Quade

...
Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants