tso-d_chris

I've often wondered if it would be feasible to take a mount from a retired, large telescope, and replace the telescope with a wind tunnel, such that the angle between the vertical and the free stream velocity is variable. If the airspeed were also variable, you could even fly a canopy in such a tunnel. For Great Deals on Gear

Synthetic materials have already been taken into consideration with respect to repack cycle length. If natural fibers are used, the reserve must be repacked every 60 days (in the US). For Great Deals on Gear

Yes. There doesn't seem to be a problem caused by oscillating pilot chutes in skydiving. During deployment they're not inflated long enough for any slight oscillation to cause a real problem. Essentially it would be a solution to a problem that doesn't exist skydiving. The same cannot be said of base. The larger pilot chutes and the slower airspeed at deployment allow an oscillating pilot chute to have a much greater effect on the opening. (specifically on-heading performance). Just my opinion, though.YMMV. Why do you ask? Are you still having trouble with that Heatwave spinning up on you? Blues! Steve No. I ditched that canopy long ago. I'm not trying to fix a non-existent problem, only wondering if there is room for improvement. If we didn't look for such things we would still be jumping T-10s, which weren't broke, either. For Great Deals on Gear

The point is, the lack of improvement is assumed, without experimental data (in sport skydiving). It would be interesting to see how experimental data compares to this assumption. Currently, most people I have talked to consider F111 PCs to be superior to ZP PCs, bungee collapsible PCs excepted. However, if there is a benefit to a vented apex, and if that benefit exceeds the benefit of F111 PCs over ZP PCs, it would be beneficial, since ZP outlasts F111. The higher cost of production would be offset by a longer lasting PC. For Great Deals on Gear

Your choice of canopy with respect to your experience notwithstanding, a collapsable PC would be beneficial. A kill-line collapsable will, however, increase the risk of a PC in tow. All you have to do is forget to cock it, and it won't inflate when you throw it. One way to avoid this mistake is to have two separate points in your pack job when you cock the PC. You are less likely to miss it completely if you have planned to do it twice. Also, on many rigs, it is possible to see whether or not the PC is cocked when you do a main pin check. I agree with the others that you may need to reevaluate your present choice of canopies, but that is irrelevant to whether or not the collapsable PC will be better than a non-collapsable PC. For Great Deals on Gear

I disagree with the use of the word 'often'. I think 'seldom' is more appropriate. Most DZO's did not start DZ's because they had a financial goal in mind. They started because they like the sport and it is a passion. Sure, we need to make profit, but that is not 'often' chosen over safety. The two go hand in hand. The old saying "If you think safety is expensive, then try having an accident...." Skydivers, if they really think the DZ is 'unsafe' or is choosing profit over safety, is simply 'endorsing' that activity by jumping there. Let your feet do the walking and go somehwere else, thus removing the profit. TK I have jumped at exactly one DZ that did not cut safety corners to some degree, and I was there for a very limited time, so it is possible that I just didn't see it. That seems more like often rather than seldom. Some common things that favor profit over safety: No second jump run when warranted by a long or short spot. Different standards for wind/weather holds depending on whether or not there are tandems on the load. Holding instructors/coaches to different standards in the landing area because grounding them would reduce the number of jumps their students would make. Allowing packers to pack unsupervised. I'm not saying every drop zone is blatantly dangerous. No set of rules can replace good judgement on the part of the jumper. However, some DZs make it fairly easy for bad habits to become accepted standard practice. For Great Deals on Gear

I didn't know Pato Banton covered Legalize It. I'll have to find that. Judging by the rest of your list, you might be interested in Easy Star All Stars' Dub Side of the Moon, a reggae version of Pink Floyd's classic album. I don't like most covers, but this one is very good, at times better than the original. (Never thought I would say that.) For Great Deals on Gear

M*A*S*H Cheers The Simpsons That 70s Show For Great Deals on Gear

I once read about an effective (and free) treatment for Alzheimer's Disease. It is unfortunate that profitability is such a big factor in marketing medical technologies. For Great Deals on Gear

I have heard it broken down into three types of drag, instead of two, which accounts for the discrepancy. Those are parasitic drag, which would be lines, jumper, PC, d-bag, bridle, etc; induced drag, which is the horizontal component of the lifting force (thrust on a canopy! ), and profile drag, which is the drag associated with the actual airfoil due to frontal surface area, viscosity of the air and the associated friction along the skin of the airfoil, etc. I didn't get the terms from a Fluid Dynamics class, though, just personal research. They could be incorrect. For Great Deals on Gear

Isn't induced drag the horizontal component of the Total Aerodynamic Force? In the case of sport canopies, this is actually induced thrust, since they are trimmed to angle down towards the ground a bit, and the horizontal component of that force is positive in the forward direction. For Great Deals on Gear

I don't think that is always true. It may not even be true most of the time. Often DZs set policy based on profit, and not safety. That is not good for skydivers. Granted, it doesn't always happen that way, but often it does. For Great Deals on Gear

In almost all cases, freefall pilot chutes do their job in under 1 second, so whether they oscillate doesn't really matter, does it? As was said above, adding an apex vent would: 1. Make them open slower, 2. Make them harder to manufacture, and 3. Make them more bulky...none of which would be very helpful. The reason I am curious is that I have talked to hard core CRW dogs in the past that swear that, all else being equal, a ZP pilot chute will contribute to off heading openings, whereas as deployments from F111 pilot chute are straighter. I have also heard this elsewhere. The only reason I can think of for this to be true is because the F111 pilot chutes are venting air through the fabric, having a similar effect as a vented apex. This is a guess, and there could in fact be other reasons. Additionally, if BASE pilot chutes have the vents with benefit, wouldn't that benefit be increased with higher deployment speeds of skydiving, even if it's not as critical to have on heading openings? As far as the reduced surface area, that is easily added back with a slightly increased PC diameter. The extra bulk seems like it would be minimal. I understand the extra build expense, but if there was an actual benefit, it seems it would be worth it if there proved to be a benefit to having a vent. For Great Deals on Gear

I'm not following the logic behind a vent causing a streamer. Could you elaborate? For Great Deals on Gear

Thanks for that info, Sparky. I was always under the impression the vent was there to reduce oscillations. For Great Deals on Gear

I really wasn't commenting on whether wearing a seatbelt is a good idea, or whether or not I agree with seatbelt laws. I just pointed out why seatbelt laws are so widespread. I've had my life saved once by my seatbelt, and I survived another accident because I wasn't wearing it. I almost always wear it these days; odds are greater that it will help than hurt. On the other hand, I'm not inclined to jump with an RSL, and I don't own an AAD, although I have in the past. I certainly don't want to see AADs mandatory. For Great Deals on Gear

Forgetting about it increases the risk of two out if you go low and dump your main at, say, 1500 feet. My main deployment hard deck is much when I have an AAD. There is no piece of equipment you can add to your gear that is 100% transparent. It would be nice, but there are possible scenarios when even the best safety equipment can be detrimental. Safety equipment tends to help far more often than it hurts, but the potential for harm is always there if we think of that equipment as transparent. For Great Deals on Gear

It seems to me that if round canopies oscillate less with a vented apex then the same principle would apply to pilot chutes. I cannot remember ever seeing a non BASE PC with a vented apex. Is there a reason it is not done for skydiving pilot chutes?

First, demo before you buy. Nothing you read in a review or an advertisement can compare to what you can learn by actually jumping the canopy. Second, I would highly discourage going from a low aspect ratio canopy to a high aspect ratio canopy and downsizing simultaneously. You will find a large performance increase without the downsize. This would, of course, preclude all the canopies you are considering, except the Crossfire2. However, the Sabre2, Safire2, Lotus and Pilot are all likely to outperform your Diablo at similar loadings. IMO jumpers are over eager to downsize. The best swoopers I know put several hundred jumps on large canopies before moving on to smaller stuff, which was still big by todays standards. Having a tiny canopy does not equate to having the skills to fly it. For Great Deals on Gear

To get federal tax money. New Hampshire is the only state in the union that has had the spine to keep the seatbelt a personal choice. Live free or die. For Great Deals on Gear

This is what I have always heard from instructors as well, including a Strong tandem examiner. Track out of spins. For Great Deals on Gear

I would recommend you keep looking. A canopy made with zero porosity fabric would be better suited to you. Some models that you might consider asking your instructors about are Sabre2, Safire2, Lotus, Pilot, Silhouette (ZP top skin only) or Spectre. If you are on a tight budget, a Sabre (1) or a Safire (1) are both available used at lower costs than many other models, as both models have been discontinued in favor of sequel versions. For Great Deals on Gear

Thanks.

You are correct, assuming two positions of the finger (up or down). You win nothing. Sorry. For Great Deals on Gear

In this case, each option has two possibilities, and choosing one option does not preclude other options being chosen, if I understood the original problem correctly. So each option has two possibilities, with a total of five options, which works out to 2^5=32. If each option had three possibilities, the total number of possibilities would be 3^5. With four possibilities, the answer would be 4^5. Now for the quiz : How high can one count on their hands, assuming both hands are used, and they each have five fingers? For Great Deals on Gear