fudd 0 #1 December 2, 2003 The transparent canopy idea got me thinking... How about a biplane canopy? Could make malfunctions interesting, how do you deal with a three-out situation! There are only 10 types of people in the world. Those who understand binary, and those who don't. Quote Share this post Link to post Share on other sites
fudd 0 #2 December 2, 2003 Here is a picture of what I'm thinking of. It's a kite, but could one make such a canopy? I guess deployment would be dificult (probably would have to be two-staged or more). Packing would be horrible. Flight characteristics would be interesting. There are only 10 types of people in the world. Those who understand binary, and those who don't. Quote Share this post Link to post Share on other sites
gus 1 #3 December 2, 2003 I'd love to see it done! As usual I don't really know what I'm talking about but I think the point of stacking wings on top of each other in aeroplane design is to get more lift from less wingspan - and less wingspan means less stress on the structure of the aircraft. So I'm not sure the logic would really apply to canopies but it sure would be an interesting experiment! GusOutpatientsOnline.com Quote Share this post Link to post Share on other sites
JeffD 0 #4 December 2, 2003 I was thinking about this once too, and one of the Canopy Manufacturers stated that they had experimented this and the canopies needed to be 1 chord length apart to fly properly. But for handling I have no Idea. Quote Share this post Link to post Share on other sites
quade 4 #5 December 2, 2003 You -could- do a lot of things and for some special purpose demo or movie, yeah, a bi-plane canopy might be interesting. I think all of the regular jumpers in the audience would laugh their asses off, but you certainly -could- do it. You'd have to find a way for it to make sense within the context of the story, but it's certainly possible. However, for day-to-day usage, there would be very few advantages and quite a few disagvantages. When airplanes were being made as bi-planes, it was because the materials at the time were very weak and it was the one way to have enough wing area and still be strong. The two wings acted together to created a strong, cross braced box structure and help keep each other from flexing. Because of all the cross bracing, they had a LOT of drag. One of the major goals at the time was to build a single wing that could support itself without all the cross bracing and associated drag. Once that happened, airspeeds improved dramatically.quade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
pchapman 279 #6 December 2, 2003 FWIW, I know a biplane paraglider has been built. A fun experiment, but it didn't lead to anything. Believe it was by the paragliding company Apco. Saw the pictures, but don't seem to have a copy. So a biplane ram air wing has been flown, but I don't know of a freefall deployable one. Peter Chapman Toronto, Canada Quote Share this post Link to post Share on other sites
gus 1 #7 December 2, 2003 There's a thread here where CobaltDan says Atair built and tested one for fun but there aren't any pictures . GusOutpatientsOnline.com Quote Share this post Link to post Share on other sites
riggerrob 643 #8 December 2, 2003 Yeah! What Quade said. The only reason airplanes were built as biplanes was for structural reasons. All the drag created by all those struts and wires was insignificant at the low airspeeds early airplanes flew at. Since the strength - and weight - of a beam is directly related to the square or is it cube of its depth (any structural engineers in the audience?), a biplane can easily have a "depth" of 2 or 3 meters (yards) and a corresponding light weight. Since modern mono-plane parachutes already have long suspension lines, they already have the structural advantage of a deep beam. The disadvantage of any biplane is that the high pressure area under the top wing interfers with the low pressure area over the bottom wing, reducing the amount of lift both wings can produce. This is why Atair (or was it P.D.) need at least one chord width between the surfaces on a biplane. The only way the Wright brothers were able to fly - a century ago - with a tiny engine was by keeping structural weight low. A biplane gave the Wright brothers a light structure and a massive wing area within a reasonable wing span. The Wright brothers flew with a wing loading of 1.6 pounds per square foot. How many modern skydivers exceed 1.6? Quote Share this post Link to post Share on other sites
billgkerr 0 #9 February 14, 2011 How about this! I know it isn't a chute, but it does seem to fly. Anybody got more info? I found the pictures on a PPG forum with this message: ########### After an amazing collaboration between Boeing and some very smart Korean designers a wing is now flying in both single and tandem format that is a bi plane type recreationalparaglider, it has a normal paraglider wing with a smaller one just under it, the lines go via a 4 riser system to the small wing (Conard) and then carry on to the large (normal) one. The canard combo wing has a glide ratio of 10.5 and that's at 65 kilometre's per hour, that makes the current recreational wings real bricks! They had real trouble trying to do any form of acro due to the unbelievable stability. Shorter line lengths to the first canopy give the pilot an unprecedented amount of control when inflating the glider, wing reactions are immediate and precise. With the line to wing ratio radical reduced this wing will out climb anything before it and speed is not a problem with designers having to strengthen the under surface's to allow it to reach its potential. With high aspect ratio wings the main problem is launch, they are pigs to A, get up and B, get straight on to wind to begin running but with the Conard it is completely the opposite with pilots thrilled and saying that it is the easiest wing they have ever launched, all this with 6.1 aspect ratio. Just when we thought we new it all and had run out of ideas..... ############## Bill Quote Share this post Link to post Share on other sites
billgkerr 0 #10 February 14, 2011 Sorry for the miniature pics. Bigger ones now: Bill Quote Share this post Link to post Share on other sites
tsalnukt 1 #11 February 14, 2011 that would be a bitch to pack Quote Share this post Link to post Share on other sites
nt8us 0 #12 February 14, 2011 i built a bi plane canopy for Steve Snyder in 1988. it was an idea he had for easily increasing payload on para point delivery systems.. packing wasnt all that bad,just propack one canopy at a time.since we actually had one that was a in use i would imagine ol snydly went ahead and patented the idea. Quote Share this post Link to post Share on other sites
kellja2001 0 #13 February 14, 2011 What if, on opening, one canopy had a 360 degree, or greater off-heading, whilst the other didn't. Stable biplane, but a heck of a lot of twists potentially restricting the surface area/effectiveness of the lower canopy. Just a thought... Quote Share this post Link to post Share on other sites
DrewEckhardt 0 #14 February 15, 2011 QuoteThe transparent canopy idea got me thinking... How about a biplane canopy? For a given wing area biplanes have less lift and more drag than monoplanes. They look good and are easier to build in a small garage but are otherwise an anachronism predating the cantilivered monoplane design in 1915 and better materials. Quote Share this post Link to post Share on other sites
Trae 1 #15 February 16, 2011 While we're dreaming... What about a bi-plane wingsuit? Might be one way to increase wing area without extending past the arms and legs. Of course there are many reasons why it wouldn't work.... and perhaps a few why it could. One poss...a tiny cross braced canopy suspended with very short lines from the torso. Perhaps the upper wing could be released to deploy the canopy. Quote Share this post Link to post Share on other sites
NewGuy2005 53 #16 February 16, 2011 Could I claim a two stack for deploying one? Quote Share this post Link to post Share on other sites
