Steel 0 #1 July 31, 2003 I pose this as a question to get different opinions. But I believe the answer is not yet proven. I have jumped my 62 with three different sliders and have yet to try the second slider on my 55. Here is what I have found with my 62. The hardest openings came from the factory slider (without a dome). I also jumped it with a domed none removeable slider. It provided a little softer opening but not a huge difference. Then I jumped it with a removeable domed slider and noticed no difference from a regular domed slider. That contradicted what I was told to expect because of the difference in the coverage of the slider over the canopy during the initial part of the opening. My 55 which I had expected to have a bomb for an opening has actually opened quite nicely even at terminal. My theory for this is that since the scaled version of the slider is so small, it restricts the canopy into a tighter nest just long enough to slow down the descent rate before inflating. That to me would suggest that although a bigger slider creates more drag it would not necessarily provide a softer opening. Of course I am aware that there is more to the opening than the slider but here I am just focusing on the effects of different sliders on the same canopy. Anybody else have theories on the matter.If I could make a wish, I think I'd pass. Can't think of anything I need No cigarettes, no sleep, no light, no sound. Nothing to eat, no books to read. Quote Share this post Link to post Share on other sites
nightjumps 1 #2 July 31, 2003 I take a very scientific approach to the sliders effect of canopy opening. I swap sliders until I find the one that works best to constrain the opening to a comfortable snivel without having to roll the nose. Quote Share this post Link to post Share on other sites
gus 1 #3 July 31, 2003 What's a 'domed' slider? GusOutpatientsOnline.com Quote Share this post Link to post Share on other sites
Steel 0 #4 July 31, 2003 QuoteWhat's a 'domed' slider? Gus -------------------- Its a slider that has a dome or a bubble built into it. Its works kind of like dearching does in RW. Even though your not increasing your surface area by cupping air you are creating more drag and therfore slowing your fall rate. That is why this slider comes down slower and slows the opening down in the process.If I could make a wish, I think I'd pass. Can't think of anything I need No cigarettes, no sleep, no light, no sound. Nothing to eat, no books to read. Quote Share this post Link to post Share on other sites
skymedic 0 #5 July 31, 2003 Sounds like a pocket slider to me... Marc otherwise known as Mr.Fallinwoman.... Quote Share this post Link to post Share on other sites
Steel 0 #6 July 31, 2003 Sounds like a pocket slider to me... 3..2..1..C-YA marc ------------------------ As far as I know, no canopy manufacturing company is even selling it. So you can really call it whatever you want. I have always heard it referred to as dome or bubble slider. But pocket sounds fine.If I could make a wish, I think I'd pass. Can't think of anything I need No cigarettes, no sleep, no light, no sound. Nothing to eat, no books to read. Quote Share this post Link to post Share on other sites
Hooknswoop 19 #7 July 31, 2003 PD's Sigma tandem canopies have an F-111 domed slider. The larger the slider, the more air it catches, but it allows the canopy to open more initially( to the size of the slider) The smaller the slider, the less air it catches, but it keeps the canopyreeefed in more. A mongo slider would catch a lot of air, but it would have any reefing effect. A tiny slider would have a lot of reefing effect, but catch very little air. Slider size is a trade-off between how much air it catches and how much it allows the canopy to open initially. Derek Quote Share this post Link to post Share on other sites
rigging65 0 #8 July 31, 2003 Usually a pocket slider refers to a slider with a two (or more) cell "pocket" attached to the leading edge of it. It's a totally separate piece to the original slider and is aftermarket. A dome-type slider just has extra material added to the design so that when it's inflated, the middle creates a "bubble" or "dome" allowing it to catch more air. It's not something that can be "added" or "removed" to a slider, it's just the way it's built. "...and once you had tasted flight, you will walk the earth with your eyes turned skyward. For there you have been, and there you long to return..." Quote Share this post Link to post Share on other sites
Ron 7 #9 July 31, 2003 QuoteEven though your not increasing your surface area by cupping air you are creating more drag and therfore slowing your fall rate. A dome slider HAS more surface area than a regular slider. It has extra material that creates a pocket. A pocket slider has pockets that increase the surface area, and catch more air. Canopies do not "Scale" well....The slider may actually be larger on your 55 scale wise as to your other canopy. But at any rate wings do not scale 1 to 1. I learned this back when I built R/C airplanes. You can't take a full sized airplane and scale it down (well you can, and several people did) It most of the time does not fly at all the same. So, it is very possible that your 55 slider is larger based on the scale. You fiqure that they would also have to scale the "extra" material to make the dome slider as well as just the L & W. Ron"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334 Quote Share this post Link to post Share on other sites
markbaur 0 #10 July 31, 2003 QuoteA dome slider HAS more surface area than a regular slider. A conical parachute having the same drag as a flat circular has less surface, so we cannot say so simply that more surface = more drag. Mark Quote Share this post Link to post Share on other sites
Ron 7 #11 July 31, 2003 QuoteA conical parachute having the same drag as a flat circular has less surface, so we cannot say so simply that more surface = more drag. You just said that a conical with the same DRAG has less SURFACE.... So I would think that if you had the same base size say 12"X 12" and one was flat, and the other was conical....That the conical would have more drag. How is this not correct?"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334 Quote Share this post Link to post Share on other sites
Steel 0 #12 July 31, 2003 QuoteQuoteA conical parachute having the same drag as a flat circular has less surface, so we cannot say so simply that more surface = more drag. You just said that a conical with the same DRAG has less SURFACE.... So I would think that if you had the same base size say 12"X 12" and one was flat, and the other was conical....That the conical would have more drag. How is this not correct? --------------------------------- If the only goal was more surface area then there would be no purpose in the dome shape. You could just simply make the slider bigger and it would be easier to make.If I could make a wish, I think I'd pass. Can't think of anything I need No cigarettes, no sleep, no light, no sound. Nothing to eat, no books to read. Quote Share this post Link to post Share on other sites
markbaur 0 #13 July 31, 2003 (Simplifying here...) The amount of drag is dependent on the projected surface. A flat circular has less projected surface than the equivalent conical. Check out your Poynter's manual, in the chapter on parachute design and construction. Mark Quote Share this post Link to post Share on other sites
cobaltdan 0 #14 July 31, 2003 a few rules of thumb that will vary depending on the design and situation: to modify the slider on a canopy for a slower opening you want to reduce the span dimension of the slider, but not necessarily the drag. reducing the span restricts the canopy more in its up position. but you still need the surface area to provide required drag. doming is one solution slightly increasing the cord dimension is another. ther are many variables at play and no hard and fast advice i can give for all situations. sincerely, dan<><> atair www.extremefly.comDaniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites
Ron 7 #15 August 1, 2003 QuoteIf the only goal was more surface area then there would be no purpose in the dome shape. You could just simply make the slider bigger and it would be easier to make. Yep, but the size and even the shape of the slider needs to be taken into account. If you just make it bigger you create other problems. By Doming it you can have the same size and shape, but more AREA....And it is the area that holds the slider at the top of the canopy."No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334 Quote Share this post Link to post Share on other sites
Ron 7 #16 August 1, 2003 How are we not agreeing here? We are saying the same thing."No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334 Quote Share this post Link to post Share on other sites
