Jeb Corliss Landed his wingsuit

[davelepka 4]

Quote

Because a suit and its pilot can travel at a trajectory not equal to and not decaying toward the gravity vector, there must be a force to maintain that trajectory. This is accomplished almost entirely by the net effect of fluid(air) being turned or deflected from it's original state, thus creating a dynamic force that In physics we call lift.

A wingsuit is most definitely flying.

As for ground effect, I too doubt that it played a significant role in this incident. I also doubt that it has much observable effect on any "proximity" flight done by a wingsuit. For one, the general rule of aviation ground effect would show that it is all but inapplicable to most wingsuit flight currently being shared via publicly viewable video.

Of course, the GA common belief of aerodynamics in not always similar to the true physics behind the events.

I don't know your educational background, but that's more of what I would expect from a college physics professor/pilot/skydiver/wingsuiter. Informative and a contribution to the discussion.

[Calvin19 0]

Quote

I don't know your educational background, but that's more of what I would expect from a college physics professor/pilot/skydiver/wingsuiter. Informative and a contribution to the discussion.

Yeah. They called me at home.

[theonlyski 3]

On facebook:

Quote

Jeb Corliss
Thank you every one for the well wishes :) I am fine and relatively unhurt. Thank you to all the people that helped in my rescue and continue to help me in the hospital :) It's going to be a rough next couple months but I guess I am getting a forced 8 week vacation :) I will try to make the best of it :)

"I may be a dirty pirate hooker...but I'm not about to go stand on the corner." iluvtofly
DPH -7, TDS 578, Muff 5153, SCR 14890
I'm an asshole, and I approve this message

[kallend 1,623]

Quote

Quote

You are using an incorrect definition of lift.

Great. You pointed out that I used an incorrect definition of one term within the context of the point I was trying to make. How about contributing something to the thread and either provide a correction to my definition, or better yet, realize that the point of my post wasn't to define 'lift', it was to comment on the validity of claiming that wingsuits benefit from ground effect, and that it played a critical role in a previous wingsuit flight, and contribute to that discussion.

For an over qualifed college professor, you sure post like a high-school drop-out sometimes.

Wow, you sure get pissy when your mistakes are pointed out.

Since you show a defective knowledge of basic aerodynamics, why should anyone trust your statements about other aspects of aerodynamics?

...

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

[Andrewwhyte 1]

Quote

Wow, you sure get pissy when your mistakes are pointed out.

Since you show a defective knowledge of basic aerodynamics, why should anyone trust your statements about other aspects of aerodynamics?

Do you wander the halls of your school occasionally yelling WRONG! as your contribution to various conversations? That is pretty much what you do on here when it comes to discussions within your speciality.

[kallend 1,623]

Quote

Quote

Wow, you sure get pissy when your mistakes are pointed out.

Since you show a defective knowledge of basic aerodynamics, why should anyone trust your statements about other aspects of aerodynamics?

Do you wander the halls of your school occasionally yelling WRONG! as your contribution to various conversations? That is pretty much what you do on here when it comes to discussions within your speciality.

Pointing out an incorrect definition is not the same as shouting "WRONG". It should encourage the perp. to look up the correct definition rather than getting all pissy.

The topic has been discussed previously on DZ.COM

...

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

[wildcard451 0]

Quote

Quote

I don't know your educational background, but that's more of what I would expect from a college physics professor/pilot/skydiver/wingsuiter. Informative and a contribution to the discussion.

Yeah. They called me at home.

Bravo. [golfclap]

[davelepka 4]

Quote

Wow, you sure get pissy when your mistakes are pointed out.

Since you show a defective knowledge of basic aerodynamics, why should anyone trust your statements about other aspects of aerodynamics?

No, I get pissy when you bother to post, but make no real contribution. As one of the few people here who is 'overqualifed' to speak on physics and aerodynamics, I value your opinion and consider it to be the 'final word' on these matters, and would look forward to a correction and learning something in the process.

Meanwhile, your useless post wasn't even on-topic, it was pointing out that you thought I used an incorrect definition of a term that was secondary to the topic at hand. Using the correct definition of 'lift' or not, the purpose of the post, and how it was related to the thread, was the subject of ground effect and if it applies to wingsuits, and your 'drive by posting' didn't speak to that at all.

True to form, you still have not made any meaningful contribution to the thread. Bravo sir, consistancy is thy name.

[normiss 622]

SC get migrate to BF yesterday during the outage???

[Calvin19 0]

Quote

Quote

Quote

I don't know your educational background, but that's more of what I would expect from a college physics professor/pilot/skydiver/wingsuiter. Informative and a contribution to the discussion.

Yeah. They called me at home.

Bravo. [golfclap]

This is Bonfire, we are both allowed to make our sarcastic and completely useless contributions.

-SPACE-

[billvon 2,400]

>A wingsuit can lift 'some' of the weight of a jumper, but it cannot lift 'all' of the
>weight and provide for a zero descent rate.

It does indeed lift all the weight - just as a glider's wings support all its weight. Even if it never reaches a zero descent rate.

>My point is that you can't say one way or the other if ground effect is indeed present in wingsuits.

Ground effect is present in any vehicle that relies on lift. It was even present on the X-24 which had no wings at all - but could still land on a runway. (In fact I think it had an even worse L/D than a modern wingsuit.)

[dorbie 0]

Quote

Quote

Wingsuits certainly produce lift

Indeed, but not enough to qualify as a positive value in terms of the weight of the jumper. A wingsuit can lift 'some' of the weight of a jumper, but it cannot lift 'all' of the weight and provide for a zero descent rate.
.

Lift is lift, further, in any stable glide slope the upward vertical component of aerodynamic forces equals (is in equilibrium with) downward forces due to gravity, (weight). Any reduction in descent rate or shallowing of the glide slope would mean that upward aerodynamic forces exceeded weight briefly. The forward component of aerodynamic forces is in equilibrium with drag (in fact drag is an aerodynamic force so I'm reluctant to separate it but it helps illustrate propulsion).

As for the ground effect again, my point would be that ground effect should not be relied upon, further I said at first mention that we may never know how much ground effect was in play on the video I cited.

There is nothing magical about wingsuits that preclude ground effect when low enough.

[dorbie 0]

Quote

As for ground effect, I too doubt that it played a significant role in this incident. I also doubt that it has much observable effect on any "proximity" flight done by a wingsuit.

Calvin, I agree in general, except that my suggestion is that ground effect may have played a role in the "Grinding the Crack" video, not this incident.

http://www.youtube.com/watch?v=TWfph3iNC-k&t=1m37s

Watch at 1:36 and see the additional lift at 1:40, and consider the altitude above the smooth slope, how much was ground effect? I have no idea.

My further suggestion would be that such an experience has the potential to be a "negative training" experience if not properly understood leading to less lift than expected in a similar situation where the proximity to a smooth grassy slope was absent.

[theonlyski 3]

Quote

There is nothing magical about wingsuits that preclude ground effect when low enough.

Is it possible that nobody ever thought about it in detail because nobody figured people would be flying at a height of less than their wingspan off the ground?

"I may be a dirty pirate hooker...but I'm not about to go stand on the corner." iluvtofly
DPH -7, TDS 578, Muff 5153, SCR 14890
I'm an asshole, and I approve this message

[kallend 1,623]

Quote

Meanwhile, your useless post wasn't even on-topic, it was pointing out that you thought I used an incorrect definition of a term that was secondary to the topic at hand.

It wasn't that I THOUGHT you used an incorrect definition, you DID use an incorrect definition. Your analysis was flawed, as has been pointed out by several people now.

You were wrong, but somehow you want it to be my fault.

...

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

[Calvin19 0]

Quote

Quote

As for ground effect, I too doubt that it played a significant role in this incident. I also doubt that it has much observable effect on any "proximity" flight done by a wingsuit.

Calvin, I agree in general, except that my suggestion is that ground effect may have played a role in the "Grinding the Crack" video, not this incident.

http://www.youtube.com/watch?v=TWfph3iNC-k

Watch at 1:36 and see the additional lift at 1:40, and consider the altitude above the smooth slope, how much was ground effect? I have no idea.

I have no idea either. Without testing and and ways to test there will never be hard data.

In that video, at the times you specified, as well as other sustained consistently very low flights, there very well may be a significant amount of ground effect.

It seems you are very informed on aerodynamics, probably much more so than myself. Please take what I write here and what I have written in this thread before as opinion based on experience and a limited education in aero.

Ground effect is a complicated thing. {in response to someone else] To say that "an X-24 experienced ground effect" is in no way untrue, but No one ever flew an X-24 at low altitude in a high speed configuration. Ground effect is not "on or off", it has immense variables and not only between different aircraft. An F-4 Phantom no doubt experienced ground effect on landing, and probably around an AGL of one wingspan. But what if a pilot took it to the deck at 300kts? at one wingspan, would there be significant ground effect? how about 500 kts? Sure, the effect would be there but most likely not noticeable.

At about 130kts I have, and for long periods of time, taken a PA-30 (with the gear up) to about an altitude of 12" prop to water. Where the gear down, it would be dragging in the water from time to time. This is about <1/5 the wingspan of the plane. There was without a doubt ground effect. But, at about 10', less than half the wingspan, there was no perceivable ground effect. Even at 5' I cant be sure.[Edit to add: Of course the PA-30 on landing would begin to have a noticeable float about 1 wingspan off the ground (<80kts)] Of course a wingsuit is at WAY high angles of attack, so maybe the GF altitude range is different. I do not know. AOA does play a hugh factor though.

Quote

My further suggestion would be that such an experience has the potential to be a "negative training" experience if not properly understood leading to less lift than expected in a similar situation where the proximity to a smooth grassy slope was absent.

I think what we are seeing there, and again i do not know because I have never flown a suit that low, is Jeb controlling the flight of his suit and not in any way evidence of ground effect.

[Calvin19 0]

Quote

Quote

There is nothing magical about wingsuits that preclude ground effect when low enough.

Is it possible that nobody ever thought about it in detail because nobody figured people would be flying at a height of less than their wingspan off the ground?

I have thought about it a lot since about 2003 when I started. I imagined there would be ground effect. BUT i -think- the lifting methods and ultra turbulent flows of wingsuits would make the standard "one wingspan" rule less than reliable.

-SPACE-

[billvon 2,400]

>Sure, the effect would be there but most likely not noticeable.

Ground effect increases at higher speeds. Gliders often use this trick to do something called a "penetration approach." They dive at the ground to get as much speed as possible then level off within a wingspan of the ground. The significantly increased L/D then allows them to cover more distance than they would have if they had performed the usual sort of approach and entered ground effect with less speed.

>At about 130kts I have, and for long periods of time, taken a PA-30 (with the gear up)
>to about an altitude of 12" prop to water. Where the gear down, it would be dragging in
>the water from time to time. This is about <1/5 the wingspan of the plane. There was
>without a doubt ground effect. But, at about 10', less than half the wingspan, there was
>no perceivable ground effect.

During WWII there were several stories of damaged bombers descending to just above the water; the ground effect allowed them to continue flying and make it back across the channel. (What happened after that, of course, was still problematic - but it allowed them to crash in friendly territory.)

As a side note, the Russians once built a rather absurd nuclear bomber powered by eight JT9D-sized engines. It had stubby little wings and was more boat than airplane; it flew in ground effect at speeds up to 460mph.

[ryoder 1,384]

Quote

As a side note, the Russians once built a rather absurd nuclear bomber powered by eight JT9D-sized engines. It had stubby little wings and was more boat than airplane; it flew in ground effect at speeds up to 460mph.

http://www.youtube.com/watch?v=su141UIHqOI&t=2m30s

"There are only three things of value: younger women, faster airplanes, and bigger crocodiles" - Arthur Jones.

[Calvin19 0]

Quote

Ground effect increases at higher speeds.

[confused face]

Quote

Gliders often use this trick to do something called a "penetration approach." They dive at the ground to get as much speed as possible then level off within a wingspan of the ground. The significantly increased L/D then allows them to cover more distance than they would have if they had performed the usual sort of approach and entered ground effect with less speed.

I know, I have done that in a 102.

Quote

During WWII there were several stories of damaged bombers descending to just above the water; the ground effect allowed them to continue flying and make it back across the channel. (What happened after that, of course, was still problematic - but it allowed them to crash in friendly territory.)

exactly what I was doing in the PA30, minus the damage and crash. It gave me an extra 5kts at a given power.

Quote

As a side note, the Russians once built a rather absurd nuclear bomber powered by eight JT9D-sized engines. It had stubby little wings and was more boat than airplane; it flew in ground effect at speeds up to 460mph.

Ekranoplan. Ground effect vehicle. there has been several civilian "swampboat" versions as well. The ekranoplan also "flew" very low, and only very low.

-SPACE-

[Calvin19 0]

Quote

>Sure, the effect would be there but most likely not noticeable.

Ground effect increases at higher speeds.

Not sure here, but I would like to share how I think it is.

The vector of the induced drag changes with speed, it moves forward. This is also the result of ground effect. When viewed as an equation as speed increases for a given load, the average angle of attack of a wing approaches zero. This means that the ability of ground effect to have a measurable influence on an aircraft also approaches zero[as speed is increased]. Thus, ground effect's perceivable influence decreases as speed is increased.

Edit to add: But, you might be able to argue that from the standpoint of an observer, a sailplane can travel significantly farther and for a longer period of time while in ground effect at speed than it can at landing speed because of the same factors I just sited. (the aircraft is in very low AOA and low camber configuration, so the difference between gravity and induced drag is very small allowing the vehicle to travel with minimal drag, and any small gain would appear to be amplified by these factors.)

-SPACE-

[CSpenceFLY 1]

Quote

>Sure, the effect would be there but most likely not noticeable.

Ground effect increases at higher speeds. Gliders often use this trick to do something called a "penetration approach." They dive at the ground to get as much speed as possible then level off within a wingspan of the ground. The significantly increased L/D then allows them to cover more distance than they would have if they had performed the usual sort of approach and entered ground effect with less speed.

>At about 130kts I have, and for long periods of time, taken a PA-30 (with the gear up)
>to about an altitude of 12" prop to water. Where the gear down, it would be dragging in
>the water from time to time. This is about <1/5 the wingspan of the plane. There was
>without a doubt ground effect. But, at about 10', less than half the wingspan, there was
>no perceivable ground effect.

During WWII there were several stories of damaged bombers descending to just above the water; the ground effect allowed them to continue flying and make it back across the channel. (What happened after that, of course, was still problematic - but it allowed them to crash in friendly territory.)

As a side note, the Russians once built a rather absurd nuclear bomber powered by eight JT9D-sized engines. It had stubby little wings and was more boat than airplane; it flew in ground effect at speeds up to 460mph.

That was built to be a troup carrier.

[billvon 2,400]

>That was built to be a troup carrier.

Yep. Six nuclear missiles and two million pounds worth of troops and gear. They were so hard to get off the water that they needed 250,000 pounds of thrust to get into the air; once they were in the air they'd shut down about half their engines. They turned _extremely_ slowly since they couldn't bank much. That meant they couldn't easily avoid obstacles; they'd rely on sighting obstacles far off and firing up the extra engines to get enough altitude to turn.

Sounds like it was a little nerve wracking to fly. (drive?)

(Sorry completely off topic; we now return you to your thread already in progress.)

[mutumbo 0]

yikes. no thanks. lol

Thanatos340(on landing rounds)--
Landing procedure: Hand all the way up, Feet and Knees Together and PLF soon as you get bitch slapped by a planet.

[AggieDave 6]

Quote

>That was built to be a troup carrier.

Yep. Six nuclear missiles and two million pounds worth of troops and gear. They were so hard to get off the water that they needed 250,000 pounds of thrust to get into the air; once they were in the air they'd shut down about half their engines. They turned _extremely_ slowly since they couldn't bank much. That meant they couldn't easily avoid obstacles; they'd rely on sighting obstacles far off and firing up the extra engines to get enough altitude to turn.

Sounds like it was a little nerve wracking to fly. (drive?)

(Sorry completely off topic; we now return you to your thread already in progress.)

Much like a lot of things invented or built during the Soviet era: "Should we make it this big? NYET! We should make it bigger!"

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