Walking bag vs. dragging container

[kimemerson 7]

Great discussion, guys. Thanks.

Gary, I think, from looking at the photos, I might be thinking of the "stack" pack.

[Airviking 0]

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...We all tend to think of a parachute opening and flying the direction the nose is facing, but I don't think that is true all that often....

Not having nearly the experience level of others in this conversation, I can only contribute an engineer's take, and that is that the orientation of the tail has more influence than the orientation of the nose. It's the tail that inflates first, no? And the nose last?

I believe you have my stapler.

[peek 20]

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... that the orientation of the tail has more influence than the orientation of the nose. It's the tail that inflates first, no? And the nose last?

Perhaps, but I really don't know. Until someone does some research on it we won't know. And it wouldn't be an easy project because there are so many variables in parachute inflation.

It's easier to just argue about it on the internet.

[airtwardo 6]

... PRO packing is an acronym for Proper Ram-air Orientation.

When it first came out, 'PRO' was an acronym for Probably Reserve Opening.

~ If you choke a Smurf, what color does it turn? ~

[Halfpastniner 0]

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...We all tend to think of a parachute opening and flying the direction the nose is facing, but I don't think that is true all that often....

Not having nearly the experience level of others in this conversation, I can only contribute an engineer's take, and that is that the orientation of the tail has more influence than the orientation of the nose. It's the tail that inflates first, no? And the nose last?

In BASE jumping, we use a tailgate in order to force the nose to inflate before the tail. When the tail is allowed to inflate before the nose (especially with no slider), lineovers are much more common. I cant say for sure in skydiving, but I think the nose is supposed to inflate first.

BASE 1384

[Beatnik 2]

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When the tail is allowed to inflate before the nose (especially with no slider), lineovers are much more common. I cant say for sure in skydiving, but I think the nose is supposed to inflate first.

The tail is a point where there is the lowest volume, similar to the apex in a round and should always inflate before the nose. When a canopy inflates it will go from the lowest volume point to the largest. I don't have a lot of knowledge in the subject of tailgates but I can't see how it would change inflation. I would tend to believe there is another reason that tailgates are used.

[pchapman 261]

Let's be careful in this side issue of canopy inflation whether we are talking about bottom surface inflation (spreading of the canopy) or cell inflation (filling cells with air).

Beatnik I think is talking more about cell inflation while the heading issue will be affected first by how the canopy spreads.

We also have to be careful when comparing openings with sliders and without (eg low speed BASE with a tailgate).

I'm not solving any argument here, just saying be careful what exactly it is one is discussing.

[Beatnik 2]

Good point. I don't think bottom surface inflation can be considered inflation by definition but even thinking about it, it is kind of a grey area. I understand what is being conveyed though.

Not completely convinced that the spreading will be the first thing to affect heading as per the discussion. It is one of the first things to happen but it could be debated that the canopy spreads because of inflation and not spreads then inflates. I don't know the answer and am playing devil's advocate.

It is an interesting thought since it will eventually spread anyways. Single surface parachutes show us that but that doesn't prove it happens first. It could also depend on whether the brakes are set or not. When they are set there will be a small volume to fill whereas without any brakes set there isn't anything cupping.

[kimemerson 7]

Just to help me get up to speed:
What's a tailgate?
How does the tail of a ram-air inflate first?
Does inflation move from tail to nose?
Would brakes being set cause the tail not to inflate first or just to be inflating while the nose is too, rather than ahead of it?
Thanks

[Beatnik 2]

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What's a tailgate?

A tailgate is a device to control the steering lines during inflation. It is another small piece of line that wraps around the steering lines and is held together with a rubber band. Essentially it controls the steering line movement. There is a lot more information on this site:

http://www.basicresearch.com/tailgate.htm

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How does the tail of a ram-air inflate first?

With a canopy inflating regardless of shape, air will fill low volume areas first. With a ramair the air will enter the cells and will fill the tail first. This doesn't mean that ther areas aren't inflating at the same time but the amount of air required to fill that small space at the tail is less than other areas and because of that requires less time to fill. It will then move to the next smallest volume area and so forth. You could take a fan to one of the cells of a ramair and see what I mean. The tail will fill first then the rest. If you can find photos of a round inflating you will see the same thing with the apex filing and then filling downwards to the skirt.

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Does inflation move from tail to nose?

The filling areas really depend on the design of the canopy. I think the above answer how the air fills.

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Would brakes being set cause the tail not to inflate first or just to be inflating while the nose is too, rather than ahead of it?

The brakes not being set won't change the inflation but more factors that help it. Like what was mentioned in the above posts. The brakes set causes the tail to cup air. The cupping and slowing down actually help with air entering in the cells. Without them set, the parachute streamers more, for lack of better descriptive words.

I hope I answered your questions. They are not really easy questions to answer without getting into other areas.

[kimemerson 7]

Excellent. Thanks. I knew what a tailgate was, just never knew it had a name. I've seen it mostly as an after market field mod., a lot like soft links were before things like Slinks.

Now I can go back and understand what I already read. Thanks.