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Does anybody have any ideas on if and how valves/covers can affect the onheading performance of a vented canopy. For instance, when the covers are not aligned the same way over the span of the canopy when packing. Theoretically this could lead to uneven restriction of the airflow over the span of the canopy?

Cheers

small print: as a newbie...

From what I understand, the speed of the opening is a (big?) factor in how the heading performance operates - therefore the faster the opening the better average of heading performance...

C'mon Mac, this is one especially for you

I don't think he's asking whether having valves will impact heading performance (i.e. vs not having valves).

I think what he's asking is, given a valved canopy, would any asymmetry in how the valves are laying in each of the cells negatively impact heading performance? For example, if the valves in cells 2, 5 & 6 are laying perfectly flat, those in cells 1 and 4 are sort of half covering, and 3 & 7 are laying wide open, would that result in any appreciable difference than if they were all laying flat?

Unlikely.

Since bottom skin inflation occurs first, the canopy heading is decided before the effect of the valves is fully felt. Valves help your canopy fly effectively much sooner but I doubt they have much, if any effect on the speed of bottom skin inflation.

Feel free to shoot as many holes in this as is necessary.

PS weather in the UK is unbelievable. How can you live like this?
Wet, bored and pissed off.

They can't...

They all dream to buy a house in France!

yeah right..........

im whith Skin here,i dont think it will effect your opening unless you sew or glue them into that position


told ya to wait untill i visited aswell,come to DK we have nice weather at the time

I beleive that body position and wind has more to do with off headings than anything else. Your off heading is normally determined before you have initial or bottom skin inflation in which the valves and vents help to give you in quicker time - the wind and your body position will have already determined your off heading before the vents / valves have kicked in. (I beleive this is what Skin was saying??

Obviously my thoughts count for shit and someone may like to correct my own thoughts on this....... Generally I believe packing nuances are low down on the list for heading performance…….. again this maybe just the way I think and someone will tear my post to shreds for the school boy errors held within! I would appreciate thoughts if this is the case.....

If you are that worried get non valved or MDV - what ever makes you happy dude!

Just my bored at work thoughts........

You aint fooking wrong! - you non-island guys dont realise how lucky you are!!

I believe that during the development of the Vtec BR tested a canopy with vents on the outside cells (1 and 7), and abandoned those locations because it was causing strange heading/inflation effects. My memory of it is a bit hazy, but I seem to recall someone commenting that the end cells appeared to be inflating early in the sequence, and that effect would magnify offheadings that might be caused by other things.

just throwing some thoughts around here...... so forgive me........

although the end cells may inflate earlier on in the sequence due to vents placed on cells 1 and 7 - Would this not be rather negligble in the timing? Instead of the reasoning that the end cells were inflating earlier - would it not be that due to the end cells inflating earlier they cause some other unusual opening character? I know this must sound like gobblegook - Im not really very good at saying what I mean sometimes - I mean rather than (1) would it not be (2)???

1) Its the vents on cells 1 and 7 that cause strange heading effects
2) its the vents on cells 1 and 7 that cause xxxxx and xxxx to happen which in turn cause strange heading effects.

I know this maybe nit picking - but I can not see why vents on 1 and 7 would in themselves cause unusual effects but would perhaps cause other effects? If the inflation is first through an exposed center cell and through the ports and subsequent opened nose cells then if the vents on 1 and 7 inflate uniformly - I cant see that the minimal time between these events this would be enough to cause off headings - but I guess it might be enough to cause other effects that build toward magnified off headings from other factors?

Please remember, I am only throwing some (inexperienced) thoughts around here trying to understand more about the stages of deployment - something I know little about!! (which maybe obvious from my ramblings on this post!)

Thank you for wasting your time reading!

am i the only one that has noticed that cell 1 and 7 often is colapased after inflation of the rest of the canopy(im jumping a fox265 vtec/no valves),on some jumps they first expose acouple of secs later than the rest.im sure mac can rember me getting a 7 cell just as i flare at some jumps in Lowlands..I never had a problem about this but i has wondered(im talking short canopy rides here),on higher were you have time to do a 180 before you land it aint an issue as you have that much canopy time...

Perhaps smaller vents could prevent this...

other than that im abit whith mac i cant see how vents in cell 1 and 7 could effect your onheadding,but looking forward if some one that tested this will explain...

.... and I just thought you wanted to have a 5 cell canopy!!

I have to admit - that after witnessing you jump 15+ times it seems that your canopy keeps the end cells closed for some time - on lower freefalling jumps (3+ sec canopy rides) it was only your flaring that would pop them out - whereas your other jumps with longer canopy rides it was full drive flight after 1 or 2 + seconds that would unfurl your end cells. Im not sure if this is canopy design (do others have this with foxes?) or trim or vents withhout valves or why this occurs - I have not seen this on any other canopy I have witnessed out of the skydiving environment.

Would it be caused by the wave of air pressurising the canopy but then escaping through the non-valved vent? and thus the side of the canopy being less pressured in the end cell then the out side air trying to push through the closed cell? but this to me does not explain why then the cells would pressurise on flaring - as I thought that unvalved canopies allowed more air to escape on flaring? (which is why faber lands like shit!! hehehehehe) - but explains why they pop open with forward flight??

Again - I am still on my canopy opening / flight / pressurisation learning focus at the moment - so forgive my ramblings and perhaps school boy errors in my thoughts - just me questioning things out loud (sometimes not thinking through as much as I should) so to speak..........

Welcome home fella

Got a cheeky one in last nite so it's not all bad...

I'd agree with skin here, I think that the valves speed up the time it takes for the canopy to "fly" but don't think they increase bottom skin inflation time any. I haven't noticed my vtec/valved Fox opening any higher than a buddy of mine who jumps an Ace. However this has only been across a 100 jumps or so

Stay safe

Neil

That's not really a good comparison of the valves. You'd need to compare to a non-Vtec FOX to get a good idea of what effect the inlets were having.

The Ace has _much_ cleaner inflation characteristics than the FOX, so the fact that you are opening around the same altitude probably indicates that the valves are having a huge effect (bringing FOX openings up to the level of Ace openings).


Adding valves to different canopies can have quite different effects.