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I am not trolling. No offense, but I honestly believe that your understanding of basic physics is flawed. Speed or location with regard to the ground means nothing in aerodynamics; this is because the only force acting between the earth and the jumper is gravity, which always points straight down and does not have any horizontal component. If the earth can not cause a horizontal force, according to mr. Newton there also can not be an horizontal acceleration (F=m*a; a = F/m). No acceleration means no change in speed. Or, in other words: no effect. All forces in horizontal direction are a result of the interaction between the object (jumper/plane/parachute) and the surrounding air, and these are dependent of the speed difference between the two. Not on the speed w.r.t. an object that has no interaction with it (like the surface of the earth). Groundspeed does not cause any aerodynamic forces, simply beacause there is no interaction between the two in the horizontal direction. Still dont believe it? Drop a napkin on the floor while flying in an airliner. The groundspeed of the napkin is 500 mph, the airspeed is 0. Does the groundspeed cause any effect? No. The napkin drops straight down w.r.t. the plane. Or more precisely: straight down wrt it's surrounding air. Looking from the ground, its trajectory will be curved, so for an observer it may seem that groundspeed causes something very complex - but is does not. Now for your example: If jumper number 2 waits an hour, by the time he opens, jumper no. 1 has been drifting with the wind for an hour, giving an enormous amount of separation between the two, instead of the zero you stated. The distance between jumpers will be exactly the same in this case as when there would be no wind. (again, differences in windspeed do matter, but if we cannot even agree on the simple case, let's not make it even more complex).

You are missing the most basic point: Wind means nothing. Only the difference between uppers and lowers will influence the distance between jumpers at opening. In other words: If the wind is equally strong at all altitudes, from exit until opening, the distance between two groups will be exactly the same as when the winds are zero at all altitudes. Therefore using groundspeed as a reference is just as valid as using the faulty "45 degree rule".

I think this is the correct explanation. I had those bruises too, and they disappeared when I stopped grabbing the risers during deployment.

What is your first impression?

OK this is getting pretty off-topic. Our C182 does have a hatch, but it is not visible from the inside. The entire left side is covered by a metal panel that runs from the pilot's door until the end of the cabin. So i would say zero risk of pilot chutes escaping here.

OK, I understand the purpose of the hatch, but I think I am missing the point you are trying to make?

Found a screenshot from the inside. A panel is mounted over the entire side, so the hatch is definitely not accessible.

I found a picture that (I think) shows the door you are talking about. I still think it is not accessible from the inside, but I will check this next saturday. Because I do agree, sitting against a door with a container may not be the best idea ever.

Not on the plane Baksteen is talking about (PH-TGC). Just two doors are accessible from the inside, one for the pilot (on the left front) and one on the opposite side (right front). So only the pilot and the jumpmaster are sitting next to a door, both are not leaning against it. There may be a door behind the rear bulkhead (which looks like it may have been added later)

This explanation is so cool!! I checked/repeated your calculations while drawing the vectors on a piece of paper, and found the exact same results. I think your conclusions are correct!

First of all, I comletely agree. Groundspeed means nothing, airspeed and gravity is all the canopy "feels". There is however one detail that makes things a bit more complex. The wind is not constant for all altitudes; especially close to the ground the differences can be significant. So when you descend under canopy, the wind suddenly changes, to which the canopy has to react. Just like it has to react to a gust of wind. In theory, I can imagine this would affect the recovery during a swoop; However i do not have enough swooping experience to notice it at all.

In the first video I'm not seeing any lines outside the slider grommets either. What I do see is a couple of slack A/B lines on the right side. Could it be that those belong to the collapsed right endcell? And that pumping the brakes maybe could have solved this?

Using two protracks is ofcourse better than one, but still... The fact that both agree does not prove that the value is correct. A design flaw in the software, the electronics or the housing could have exactly that effect.

I think the graph shows the running average over the previous 4 seconds, which makes sense in order to smoothen out the curve and eliminate very short peaks due to turbulence, noise etc. Even so, the difference in average speed divided by a certain time gives the average acceleration.... which in this case is physically impossible (at least based on my rusty math capabilities)

His measured speed increases from 450 km/h to 600 km/h in just 2.5 seconds. That's 16.6 m/s^2 or 1.7 g. Obviously this measurement is complete nonsense.

The question is this: are you, at your experience level, able to judge this? To be more precise, are you able to estimate the speed at which your (somewhat malfunctioning) canopy is flying, both forward and downward? This is very difficult to say when you are still high enough to - safely - cut away. Not saying you made the wrong decision - just something to think about.

Buying your own gear at just 30 jumps is perhaps a bit early. You are rapidly adding skills at each jump and you do not have a lot of experience. Maybe consider renting different types and sizes and find out what you like most?

I've been thinking about the two different angles thing.... How does this work in a competition? I mean, how do you decide which video you give to the judges.... Do you check the footage before you upload it? Or do you get a second change to upload after a point got busted? ( I would not think so) Or is it a matter of knowing you screwed up and then decide to go for the wider angle....in which case the team may be too tiny, costing you points as well?

Its predecessor is the CX105, slightly larger, but otherwise very similar. I (and many others) have been jumping that for years, great video, but no BOSS or larger formats than HD. Imo still better than GoPro because of its reliability. It has never failed me, wheras my GoPro....well thats another story.

Hi little icerabbit, I will be replacing my CX105 this winter for a (yet-to-be-released) X3000. Looks like a great camera to me, so maybe that is an option for you (might be over your budget tough), and also: cheap CX105 for sale! ;-)

thats exactly what I did, many years ago as a student under a Fury 220 ...... except I broke 2 bones in my left hand ...

Has a solution ever been found? Cutting away my flat-top pro does not work as it should; the metal hinge does not always open by itself, I need to help it a bit after pulling the release. Not ideal, altough (after practicing it a couple of times) I am sure I will get it off my head if needed. Still, a better solution would be nice.

If your helmet and ring sight are shifting, then so are your cameras. Kinda the idea behind mounting a ring sight to the helmet. Yeah, except these movements don't totally compensate for eachother. You can try this experiment (I did!): Put your camerahelmet on your head and connect the camera to a TV. Hold your head still an now use your hands to shift the helmet around, just like the wind would do in freefall. Watch the screen, and you will notice that the image does not really move a lot. This is because a) a few mm's translation is hardly a problem when u are trying to frame a 4way team or a tamdem and b) a few degrees of rotation is not much for a wide-angle lens. Now look at your ringsite, and you wil probably see a much larger influence. This is because the site is very close to your eye, so even only a few mm's will have a huge impact. The result is that the ringsite tells you to compensate way too much, resulting in bad framing. Ofcourse there are ways to overcome this problem, like getting a helmet that fits tight to your head so it doesn't move, and you can learn to compensate for it, but this will cost you some jumps. Or you can duct-tape your goggles

This is a pic of my goggles. I used this system for 2 yrs now, it works great! Just before exit and every now and then during freefall I close my right eye to check the framing. What you see is definately what you get! My new helmet (Flat Top Pro) does have a ringsight, and I find it much more difficult to get the framing right. There is quite a bit of difference in framing in the air as opposed to on the ground. When the helmet shifts just a tiny bit, so does the ringsight, causing me to adjust my head accordingly, which is a lot. Only drawback so far: I would need a pair of goggles for both my camera helmets, and if I would accedentally mix them up, I would be screwed

COOL!!! This is almost exactly what I did, even your discription of how you did it is identical. Only difference: I only use 1 eye for framing, and I use cheap sunglasses instead of goggles. They don't fog up. And it works great. I've been using this for two years now, mainly for shooting 4-way competition. Will post a pic later.