stormglove 0 #1 January 28, 2011 Hi, I'm currently working at columbus AFB and we are having trouble finding out some info on how exactly these LaMoigne slots work on the chutes used for some of the aircraft. any help would be great. We are trying to figure out if the LeMoigne slots on canopies are always open (as in when they are packed) or if they are closed and get released when pulling the steering toggles (sort of like how a lot of ram air chutes are packed at 50% brakes). Sorry if this is not the place to ask this question. I have 580 jumps but all on ram air canopies so I really have no idea how these slots are meant to work. We are to figure this out so we can explain it to the pilots so they know what to expect. Thank you for any help. Blue Skies... Quote Share this post Link to post Share on other sites
riggerrob 643 #2 January 28, 2011 Try reading manuals for Para-Commander, Papillon, Crossbow, Starlite, Lancer and other Lemoigne-class canopies. Somewhere - in one of those manuals - I saw a diagram explaining how slots improve the glide ratio of high-performance round canopies. At risk of simplification, Lemoigne slots divide the canopy into a series of high-aspect-ratio, single-surface airfoils, perpendicular to the wind. By allowing air to vent towards the rear, they create a high-speed airflow over the top of the canopy and generate a bit of lift, flattening the glide ratio. Similarly, the pulled-down apex is just another way to flatten the canopy, reduce drag and flatten the glide ratio. Most of the forward speed - of Lemoigne-class canopies - comes from large drive-windows in the rear gores. Compare a Lemoigne-class parachute with a para-sailing canopy and you will notice that the large "church window" drive window is missing from the back of the para-sailing canopy because it derives thrust from a boat motor/tow rope. Pulling down on steering lines closes some of the slots, reducing thrust on that side, forcing the canopy to turn. But what do I know, I only made 1.5 jumps on a Crossbow! Hah! Hah! Quote Share this post Link to post Share on other sites
JerryBaumchen 1,468 #3 January 28, 2011 Hi storm, Quote they are closed and get released when pulling the steering toggles There is no 'open/closed' about them. When packed they are merely folded to lay flat. When the canopy opens/deploys they are then in full flight. On ParaCommanders, Papillons, etc the steering lines are attached to them to control the canopy. I have no idea on just how these are 'on the chutes used for some of the aircraft.' A photo or two of your canopy(s) might help us in knowing more about your inquiry. JerryBaumchen PS) Rob, the Crossbow did not have LeMoigne slots; they used Derry slots for steering. Although Dan Abbot came up with a 'slick' construction technique to mimic a Lemoigne slot. Quote Share this post Link to post Share on other sites
mjosparky 4 #4 January 29, 2011 Here is what they look like. Sparky http://www.flickr.com/photos/53825637@N06/5397836614/ http://www.flickr.com/photos/53825637@N06/5397836622/My idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
LouDiamond 1 #5 January 29, 2011 If you can provide a model number of the specific system you are asking about I am sure the information can be tracked down either in a TM and or the manufacturers manual. As has been mentioned, the slots are typically always open, they just get folded during the packing process of the canopy. Are these bail out systems or part of a chair?"It's just skydiving..additional drama is not required" Some people dream about flying, I live my dream SKYMONKEY PUBLISHING Quote Share this post Link to post Share on other sites
hackish 8 #6 January 31, 2011 Besides Rob who already answered another good person to query would be beatnik who probably has a copy of the manual for every canopy made before 1980 :) -Michael Quote Share this post Link to post Share on other sites
