RMURRAY

She is in Sudbury. If the tunnel in Niagara is going to be worth the short trip it will have to prove it to us - until then, it is just a tourist attraction like everything else there.

on track to get the Kodiak next month???

yes, you are right - poor choice of words. anyway, this discussion is not about cross braced...

In other words, in turbulence you should fly as close to the stall point as possible. Is that what Mr. Sherman is saying? Mark no, he is not. here is what is in the article. "We do, however, recommend that you fly near deployment brake configuration or depth" Nancy is going to comment on this subject. She feels it needs urgent attention. What I am hoping is that several industry experts can rethink what they have stated in the past and come up with a simple unified statement we can all go by in the future. I tend to feel immune to turbulance (highly loaded x brace) but tend to go to quarter brakes when it gets real bumpy close to the ground - just because I feel more in control and ready to act. rm

here is the entire article - I am hoping John or Nancy respond (I let them know the subject is being discussed)..... What to do in Turbulence? 1/23/2004 Necessary Action when Encountering Turbulence The purpose of this article is to illuminate on the facts necessary for jumpers to make an informed decision, so that they may better plan their corrective/preventative action when encountering turbulence while flying their ram-air parachute. We are aware that others have published information contrary to what will be presented here. It is for that very reason we write this article. We believe this is a major safety issue, and that there should be a hearing and finding by the USPA Safety and Training Committee. Encountering turbulence under a ram-air canopy can be unnerving at best. It can and has led to canopy collapse and sudden impact with the ground. Turbulence can happen at any altitude, however, it is the most dangerous when it occurs close to the ground because of the limited recovery distance. To fully understand the problems created by turbulence we must first understand some basic aerodynamics. The principal, which keeps a ram-air flying, is one of pressure differential. It’s the same principal that makes airplanes fly. The pressure on the top of the canopy aft of the thickest point is reduced to less than ambient. This pressure reduction is caused by the flow of the air over the top surface, and the differential of this flow from the flow over the bottom surface. When the air mass is encountered by an airfoil it divides at what is known as the stagnation point. From here some of the air goes over the top of the canopy and some of it goes below the canopy. The air going over the top is accelerated, ‘cause it has to go further, to keep up with the air going under the bottom. The further the air goes the greater the pressure reduction. This pressure gradient is called the “Boundary Layer”. It is progressive in its flow characteristics from the surface of the skin to the “Free Stream Velocity” (the full uninterrupted flow of the air around the airfoil). At the surface (of the canopy) there is no flow, only a reduced pressure. This is why when you stick your fingertip out the door of an aircraft you don’t feel much air flow. As you progressively expose your finger, the airflow becomes greater. It is this boundary layer we are concerned with. If this boundary layer becomes detached from the skin of the canopy, a loss of lift is encountered and what looks like a collapse ensues. This boundary layer can be blown off the top of your canopy as a result of turbulence. Considering the above, and understanding the axiom “The moment of greatest lift on an airfoil is just prior to an impending stall”, which is taught to every student pilot, tells us that the boundary layer gets stronger as we approach a stall. Why is this? It is because the air flowing over the top must go further and necessarily faster to meet with the air passing on the other side of the wing. Therefore the pressure differential is greater, and the boundary layer is stronger, making it harder to blow off. Understand we are not advocating that you fly at just above a stall. This would be dangerous, as a sudden gust could change the airflow inducing said stall. We do, however, recommend that you fly near deployment brake configuration or depth. This is the flight mode you would want to go to if your canopy did lose lift. Remember, pilots are taught to “reduce to maneuvering speed” when encountering turbulence. One of the considerations for this procedure in powered aircraft is to reduce the structural load, a minor concern for ram-air parachutes. But recognize that at deployment brake depth we have greater lift and a stronger boundary layer, which would be more difficult to separate. Think of it in these terms, if you should be so unfortunate to lose your boundary layer due to turbulent conditions, your canopy may fully or partially collapse. When we want to make our canopies open or re-open faster, what do we do? We set the deployment brakes. If you want your canopy to re-inflate quickly you’d best be in some stage of braking (toggles pulled at or near brake setting). This will cause your canopy to recover more quickly- no matter what kind of canopy we’re talking about. The only time we need to be overly concerned about turbulence is as we get close to the ground. If your canopy bumps and breathes or even partially collapses at 1000’ or 500’ feet - so what! There is plenty of time for it to recover. The time that is takes to recover is about equal to your deployment time. The notion of “sacheting” or front “risering” out of the turbulence doesn’t make sense aerodynamically, nor will it help you avoid the problem in the first place. Turbulence travels around with the air mass, rising with the thermal activity, descending in the downdrafts. Understanding thermal activity will prevent surprises, and help you to avoid mishaps. Remember for example, not to land directly downwind of tall trees or buildings on a windy day. Land on the upwind side of the runway on a hot (thermally) day, rather than the downwind side. Try to land where the clouds cast great shadows on the ground – you’ll more likely encounter smoother air. For a wonderful explanation of turbulence as it relates to aviation, read Peter Lester’s Weather Smart article at http://www.met.sjsu.edu/~lester/ws_aug03.html. Written by: John Sherman, USPA I/E, Master Rigger, Commercial, Instrument, Multi-engine Pilot, Medallist In 4 Way, 10 Way, Style & Accuracy, US National Championships, Designer of the Racer, AngelFire Reserve, & FireBolt Elliptical Canopy, Tandem, Student, Military and BASE Canopies. Nancy LaRiviere, USPA I/E, Tandem Examiner, Senior Rigger, Commercial, Multi-Engine Pilot, Double Bronze Medallist 2003 World Championships, Multi-time U.S. Nationals Medallist and U.S. Team Member, Holder of 10 World Records, 5600 jumps, Canopy 102 Coach, President of Jump Shack

Peter, not that turbulance was confirmed but I thought that I would point out the relatively recent technical article by John Sherman and Nancy LaRiviere. Here is part..."Understand we are not advocating that you fly at just above a stall. This would be dangerous, as a sudden gust could change the airflow inducing said stall. We do, however, recommend that you fly near deployment brake configuration or depth. This is the flight mode you would want to go to if your canopy did lose lift. Remember, pilots are taught to “reduce to maneuvering speed” when encountering turbulence. One of the considerations for this procedure in powered aircraft is to reduce the structural load, a minor concern for ram-air parachutes. But recognize that at deployment brake depth we have greater lift and a stronger boundary layer, which would be more difficult to separate"

from www.skyworksrigging.com - not sure how busy he is at the moment....... Mark "Mel" Lancaster Owner 2222 Buffalo - West springs Hwy. P.O. Box 507 Buffalo SC United STates 29321 (864) 429-8428

fluff....rubber bands work well for the very important job of keeping the canopy in the bag until linestretch AND deploying lines in an orderly manner. When needed they break. yes, they require some work to change out. no big deal.... rm

nick, how many jumps will the old version last? are you guys recommending a change out to the new style? I tend to like the old since they have got to be easier on the lines than any machined and polished ring. rm

I have not called them yet but anyone know why they moved away from the RDS rings using the plastic bit and the normal grommet? Looks like they are using an all-stainless one now. rm

the last used VX I bought I made sure it was made in Spain and not Tennesee - where is your FX from? rm

I think there is the idea out there that you can pack on as much clothing as you want. It is not true - you need to be able to handle any sitiation. Best is to buy the best type of clothing possible - ie from MEC in Canada. high quality, thin and warm. Also, just get used to the fact your fingers will be cold by the time you land. I find winter jumping great - we get the usual group of local lunitics along with hardcores from other DZs that close down. rm

good information! "300 HMA" from PD, "350 HMA" from NZ Aerosports and the blue "340 HMA" from Skyworks are all really the same size - is that true? does your Velo break lines because there are less of them to carry the load compared to a JVX or VX? rm

I asked MEL this once --- continuous lines mean more drag which you do not want for a HP canopy. rm

I got a new sabre 170 at 20 jumps and had the same problem. make sure the container and main D bag is made for the 135 or bigger. Seems obvious but make sure you are packing on a good surface with some friction - like carpet. Then get someone with lots of experience with different rigs (like a packer) to show you their technique - from that you will probably customize a bit to make up your own technique. I still use the method from that 170 even though it is not the best for my sail jvx.... rm

While sewing a pocket usued to be the thing to do years ago, installing a domed slider is a better solution. Sewing a pocket on it requires a master rigger to do it (alteration) and the pocket if made improperly can lead to a cutaway. We first made pocket sliders around 1992, but again I no longer recommend them to anyone. The domed slider has a more consistent opening than the pocket slider. Cheers, MEL I would get one of MELs dome sliders. I have seen a sabre1 170 go from unjumpable (at terminal) to soft consistant slow openings. PD should have fixed this long ago.... rm

agreed. I cannot imagine taking to a car wash. I use the recommendations of Bill Booth on the RWS website - whatever they call themselves now. I have cut and pasted in threads like this many times.... edit: here it is again.... Washing Your Vector Over the years we've seen some extremely dirty Vectors! We've found that many people are unsure how to get their container clean. For that reason, we have put together the following instructions on how to make your Vector smell and look good again. The best way to wash a rig is the "good old fashion way" with slightly warm water and Woolite. Use a big tub; let the rig stay in the soapy water 4 hrs. Occasionally swish the rig around in the tub to loosen dirt. Drain soapy water, fill tub with clean water, and swish rig around until the clear water becomes soapy and cloudy. Drain tub and repeat until all soap and dirt residue are gone, usually in 3 rinses. Let the rig naturally dry, without direct sunlight. We usually allow a small fan to blow air past it to speed up the drying process. We do not recommend using a washing machine. Extended agitation in a washing machine could have negative effects in the long run. This also requires you to wrap the heavy hardware to minimize damage to the machine. © 2000-2003 The Uninsured Relative Workshop, Inc. All Rights Reserved. rm

come on up to Parachute School of Toronto (PST) in Baldwin, we are jumping year round.... rm

288 manta 170 sabre 150 stiletto 115 FX 98 VX 97 JVX 85 JVX (sail)

the Thielert Centurion 4.0 is turbocharged V8 350HP diesel so is not really a direct replacement for the 206 engine. Diesels have a very high compression ratio so everything needs to be "beefy". The 4.0 is liquid cooled. for more info on diesels for aircraft check out dieselair.com - very interesting stuff.... rm

agree completely but I guess someone has to buy the new gear and then sell at less than half price a couple of years later. My first rig was new but never again - I'd rather spend the cash on a coach/camp or just jumps... I would just buy everything separate if needed. it's not rocket science. rm

hoping for really cold weather so they can plow the runway and we can jump again - from the plane with no door.... rm

I asked Keener about shelf life. They only know how long they have to get them to the military..... "The military requires that the bands it purchase be no older than six months. I do not know how long they maintain them in inventory. Sincerely, Richard Michelson Keener Rubber Company"

a couple of times I just found someone coming over (from UK or Germany) and had it sent to them. They just carried with them like it was their own... rm

excellent post. I wish we all could read a post from everyone who has banged themselves up with a note that starts with these words. hope you are healing well... rm