I got one jump on a Unit, best damn canopy I have ever flown, however vented people are right, jumping conventional canopies will kill you and it's just madness, should not be done, you will die, they will open all fucked up and off heading, you will strike things left and right, and you won't be able to free fall anything lower than 150'. All the mojos and aces should be burnt to the ground now, please go and burn those canopies now before you die.
I am hotknifing a the bottom skin of a cruiselight as we speak so I won't die.
I am hotknifing a the bottom skin of a cruiselight as we speak so I won't die.
You know you have a problem when maggot is the voice of reason at the exit points
Thanks for those helpful words Mac. Perhaps my 'recommendation' was inappropriate. Just trying to share my experiences as a newby jumper on a vented canopy. I qualified my comments by trying to be humble and stating the limited nature of my experience. I think confidence in your kit is very important. If you have are worried about opening with brake settings set too deep and stalling whilst peering over the edge, your mind is not where it should be.
Should I refrain from passing comment until I have a minium level of experience? Jump numbers? You tell me.
Should I refrain from passing comment until I have a minium level of experience? Jump numbers? You tell me.
Shelley, I'd suggest having a look at poster's details when reviewing the advice given. There are some low key posters who have close to a 1000 jumps and others who are critical, frequently passing comment and have very little practical experience (and they are crap jumpers to boot).
With a notable exceptions there seems to be an inverse relationship between the number of posts a person makes and the number of jumps they have.
Good luck
With a notable exceptions there seems to be an inverse relationship between the number of posts a person makes and the number of jumps they have.
Good luck
Lucifer 0
QuoteCell Inflation: After the bottom skin expands, the cells fill with air. This happens for many reasons, but a prime motivator is that the canopy will slide or hop forward (almost in the same fashion as an old style tracking jumper--by deflecting air off the bottom skin). This forward motion is not strictly "flight" (the cells are not yet inflated and the canopy is not yet formed into an airfoil shape), but rather more "deflection." This motion results in air rushing in through the nose of the canopy, pressurizing the cells (and creating the "wing" that you will fly to the landing area).
Standard disclaimer , etc.
Just trying to clarify :
As I understand the phenomenon the prime motivation of the canopy filling is the depression zone created over the canopy because of the vertical speed (relative to air) towards the ground. This depression expands the upperskin, just like inflating a chewing-gum outside-in (inside your mouth) by sucking air from outside. There would be three steps in an ideal canopy inflation :
*POC = air Pressure Over Canopy
PIC = air Pressure Inside Canopy
PUC = air Pressure Under Canopy
1) The canopy (after expansion) is deflated and act as an aerodynamic deccelerator just like said above. The trajectory is vertical. A depression is created over the canopy, thus sucking the upperskin up, making the canopy suck the air from outside. During this phase, POV < PIC < PUC so any vent will let the air inside the canopy fill the cells quicker but the canopy will inflate even if there's no forward motion and no vents.
2) The canopy is inflated, but the bottom skin is curved inside or just flappy. POC < PIC = PUC. The shape is ready to act as a wing as soon as any horizontal component will occur.
3) As the canopy begins to move forward (because of the "deflection" explained by Tom), a minimal amount of air goes dynamically in the cells from the nose (due to the relative wind). POV < PUD < PIC. As the pressure inside the canopy is greater than the pressure under the canopy the bottom skin inflates towards the outside, making a clean inflated shape of each cells.
so pretty much the same conclusions
head wind -> quicker inflation in 3) and quicker transition to flight mode (less forward speed to build before flying)
vents (any) -> really quicker inflation in phase 1) reducing the loss of altitude during this phase. the inflation also begins earlier when the canopy is still expanding
open vents (no valves) -> maybe slowing down last inflation phase in 3) but probably not noticeable
Anyone could try to evaluate the relative duration of each phase? (probably they arent practically clearly separated, mostly because the forward motion depends on when you pop the brakes and how you set them)
any comment or stupid joke appreciated : )
L.
To verify the theory of bottom skin expansion, one could make the following experiments on a windy day:
1. Pinch the nose cells and try to kite the canopy. Does it expand?
2. Fold the overhung tops of the nose cells inside and fix with tape to make the nose "straight", with no overhang. Present the canopy perpendicularly to the wind (so that it passes parallel to nose openings). Does it expand?
I think even without doing the above, it's clear that the canopy will just bunch up and flap like an old rag.
1. Pinch the nose cells and try to kite the canopy. Does it expand?
2. Fold the overhung tops of the nose cells inside and fix with tape to make the nose "straight", with no overhang. Present the canopy perpendicularly to the wind (so that it passes parallel to nose openings). Does it expand?
I think even without doing the above, it's clear that the canopy will just bunch up and flap like an old rag.
Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio
Hey Mac just a question here but who are you to say that I don't make decent decisions? Just because I'm new to BASE? You don't know much about me or my abilities to make such a statement.
remember:
"The individual is always the exception.
'Everybody can't...' but anybody can."
- Richard Bach
i.e. Mac may be correct in general, but wrong in regards to you.
The lies in learning how to throw yourself at the ground and miss.
sloppy habits -> sloppy jumps -> injury or worse