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QuoteI believe what you have pointed out in your picture is for preventing the nav light from blinding the pilot. A stall fence runs from the leading edge of the wing to the trailing edge.
Actually no, stall fences are both cases. The one you showed is a full leading to trailing edge fence. This was quite common with MiGs. (check out this for some of a MiG-19). The picture I gave is of an Embraer 140 and it, in fact, is a leading edge fence...feel free to contact them to ask. Leading edge fences are actually quite common on airlines these days, even more so on business jets.
Thanks, I was not aware of the leading edge type.
Sparky
My idea of a fair fight is clubbing baby seals
Quoteyeah, more drag with no benefit,
No I said "low speed characteristics. The Xaos isn't a low speed canopy.
Quotebut a lot of people with more talent and experience than you agree with me.
Considering a) you have no idea what my experience level is, and b) you have less than I, you're in absolutly no position to judge.
or "Lighten up, Francis"
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You're not as good as you think you are. Seriously.
You're not as good as you think you are. Seriously.
bmcd308 0
Wouldn't it be cool if two people, neither of whom even owned a canopy with this feature and neither of whom even claims to really understand how it is supposed to work or whether it works, got into a fist fight to settle this once and for all?
Holiday Boogie. Behind Manifest. 10 PM. Bring liquor and 12 oz. gloves.
Brent
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www.jumpelvis.com
Holiday Boogie. Behind Manifest. 10 PM. Bring liquor and 12 oz. gloves.
Brent
----------------------------------
www.jumpelvis.com
quade 4
This thread is hilarious.
While a well designed winglet can offer some decrease in induced drag I can not possibly imagine how these could be effective based on their size, structure and shape.
I would think it would be more effective to simply extend the existing stabilizers another inch or two.
While a well designed winglet can offer some decrease in induced drag I can not possibly imagine how these could be effective based on their size, structure and shape.
I would think it would be more effective to simply extend the existing stabilizers another inch or two.
quade -
The World's Most Boring Skydiver
The World's Most Boring Skydiver
I will agree that I have no means to judge your experience other than by reading your posts, of which there are many. But you also, have no way of gauging my experience other than my posts, of which there are very few.
You indicated that my opinion is a very poor one. My opinion is based on input from people who are consistently at the top of the pack in canopy competitions around the country. It is also based on input from people with advanced degrees in aeronautical engineering.
Are you basing my perceived lack of experience on my lack of jumps? It can't be years in the sport because I have been in this world 2 years longer than you. I just didn't have the time or the money when I started. Most of my jumps have been done in the last 2 years, now that I have more time and more money.
Those "canopy warts" are an interesting idea, but they have no effect, especially when you consider the fact they depend on internal pressure to maintain their shape, which is dependant on speed, which is exactly what is missing at the time that they supposedly give benifit.
I feel I have sufficiently floccinaucinihilipilificated the idea of winglets.
Methane Freefly - got stink?
You indicated that my opinion is a very poor one. My opinion is based on input from people who are consistently at the top of the pack in canopy competitions around the country. It is also based on input from people with advanced degrees in aeronautical engineering.
Are you basing my perceived lack of experience on my lack of jumps? It can't be years in the sport because I have been in this world 2 years longer than you. I just didn't have the time or the money when I started. Most of my jumps have been done in the last 2 years, now that I have more time and more money.
Those "canopy warts" are an interesting idea, but they have no effect, especially when you consider the fact they depend on internal pressure to maintain their shape, which is dependant on speed, which is exactly what is missing at the time that they supposedly give benifit.
I feel I have sufficiently floccinaucinihilipilificated the idea of winglets.
Methane Freefly - got stink?
now that was a witty response.
Edit to add - bmcd308's not mine
Methane Freefly - got stink?
Edit to add - bmcd308's not mine
Methane Freefly - got stink?
larsrulz 0
QuoteYou indicated that my opinion is a very poor one. My opinion is based on input from people who are consistently at the top of the pack in canopy competitions around the country. It is also based on input from people with advanced degrees in aeronautical engineering.
Being a top canopy pilot doesn't necessarily relate directly to technical knowledge of canopies (i.e. what type of modifications do what if anything). JP is basing his opinion on personal experience which you seem to claim is more valid coming from someone who wins competitions. On the other hand, I have an advanced degree in aeronautical engineering, and I can tell you that there is little to no in-depth understanding of parachutes (there is a bit with rounds, but there is just no money for researching rectangular canopies). So while the engineers and physicists of the group may have a bit more insight than others, none of them know with certainty how certain aspects of a canopy work.
QuoteThose "canopy warts" are an interesting idea, but they have no effect, especially when you consider the fact they depend on internal pressure to maintain their shape, which is dependant on speed, which is exactly what is missing at the time that they supposedly give benifit.
While obviously all canopies are low speed by definition, many still maintain a reasonable amount of pressurisation when they would be most useful during, say, a swoop.
Now, I don't agree with JP about said warts, but I also don't agree with your response here.
I got a strong urge to fly, but I got no where to fly to. -PF
QuoteNo I said "low speed characteristics. The Xaos isn't a low speed canopy.
Every canopy has a low speed, it may not be as low as a Navigator 300, but it still has a low speed.
In refrence to the wing, when flying close to a stall, that's low speed.
An F-16 has low speed flight. Its a hell of a lot faster then an Aneronca Champ, but its wings don't know that, they just know they're going sloooooow.
--"When I die, may I be surrounded by scattered chrome and burning gasoline."
"I would think it would be more effective to simply extend the existing stabilizers another inch or two. "
Personally, my opinion is that the less parasitic drag the better. I think the company that does that really small stabilizer has the best idea going. There feeling was that the stabilizer is an outdated idea and does nothing but increase drag. I find it remarkable however that the company offering a slimmed down stabilizer, which reduces parasitic drag compared to other canopies with full sized stabilizers, is also offering a canopy with "winglets" which would do nothing other than increase parasitic drag.
Am I the only person that finds this to be a bit of a contradiction?
Methane Freefly - got stink?
Personally, my opinion is that the less parasitic drag the better. I think the company that does that really small stabilizer has the best idea going. There feeling was that the stabilizer is an outdated idea and does nothing but increase drag. I find it remarkable however that the company offering a slimmed down stabilizer, which reduces parasitic drag compared to other canopies with full sized stabilizers, is also offering a canopy with "winglets" which would do nothing other than increase parasitic drag.
Am I the only person that finds this to be a bit of a contradiction?
Methane Freefly - got stink?
quade 4
Well, ya got two kinds of drag; parasitic and induced and together they add up to total drag.
At low airspeed you have low parasitic drag and high induced drag.
At high airspeed you have high parasitic drag and low induced drag.
At best glide you have where the two cross each other for the least amount of total drag versus lift.
My guess (and admittedly I have no practical data to back this up) is that stabilizers add very little to parasitic drag when compared to the winglets we've seen so far since there is so little frontal area associated with a stabilizer. The winglets on the other hand . . . I can't see how these could possibly be effective at reducing induced drag but I sure -can- see how they'd increase parasitic drag since they -are- shaped rather poorly and have a fairly large frontal surface.
It would basically be the difference between the drag of a small streamer or a whiffle-ball.
But yes, I agree with your basic observation that it is a contradiction of design to make the stabilizers smaller while at the same time adding winglets.
At low airspeed you have low parasitic drag and high induced drag.
At high airspeed you have high parasitic drag and low induced drag.
At best glide you have where the two cross each other for the least amount of total drag versus lift.
My guess (and admittedly I have no practical data to back this up) is that stabilizers add very little to parasitic drag when compared to the winglets we've seen so far since there is so little frontal area associated with a stabilizer. The winglets on the other hand . . . I can't see how these could possibly be effective at reducing induced drag but I sure -can- see how they'd increase parasitic drag since they -are- shaped rather poorly and have a fairly large frontal surface.
It would basically be the difference between the drag of a small streamer or a whiffle-ball.
But yes, I agree with your basic observation that it is a contradiction of design to make the stabilizers smaller while at the same time adding winglets.
quade -
The World's Most Boring Skydiver
The World's Most Boring Skydiver
QuoteBut yes, I agree with your basic observation that it is a contradiction of design to make the stabilizers smaller while at the same time adding winglets.
That's assuming they do the same job, which I don't believe. If I had to guess just by looking at pictures, I'd assume they do nothing at all. But that is not what test jumpers said after jumping the same canopies with and without them (see the post in the thread i linked to above). So test jumpers have qualitative evidence that the "winglets" do something other than increase parasite drag.
I don't believe they decrease induced or total drag one bit. But if the jumpers are right and they really have an effect, I believe they are experiencing a decreased stall speed and better low speed performance (bottom end of the swoop) due to decreased spanwise flow. That's just my guess.
Remember that just about every modern large plane is covered from nose to tail with all different vortex generators, fences, strakes, fins, etc. They all add parasite drag. But they improve the local flow around some feature of the aircraft, delaying separation somewhere for some reason (or actually causing predictable separation, to prevent oscillation). It's a tradeoff. Add drag to fix some other problem or improve some other characteristic.
Dave
QuoteWouldn't it be cool if two people, neither of whom even owned a canopy with this feature and neither of whom even claims to really understand how it is supposed to work or whether it works, got into a fist fight to settle this once and for all?
Yeah, freakin funny. Now find someone who hasn't owned one, cause I have....
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You're not as good as you think you are. Seriously.
You're not as good as you think you are. Seriously.
hookitt 1
I haven't owned one!!QuoteYeah, freakin funny. Now find someone who hasn't owned one, cause I have....
My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto
QuoteWouldn't it be cool if two people, neither of whom even owned a canopy with this feature and neither of whom even claims to really understand how it is supposed to work or whether it works, got into a fist fight to settle this once and for all?
Holiday Boogie. Behind Manifest. 10 PM. Bring liquor and 12 oz. gloves.
Brent
It would be really cool if those people could be hot stripper chicks. This would prove they don't understand the topic, we would need much more liquor and a video camera, air matresses and a bunch of babay oil.
QuoteThis thread is hilarious.
Sure is.
QuoteWhile a well designed winglet can offer some decrease in induced drag I can not possibly imagine how these could be effective based on their size, structure and shape.
I can understand skepticism, but until you've flown it you really won't know. I hav to date jumped 124 different sizes and types of canopies (that's 46 types in various sizes) I think that gives me a little perspective on the subject.
QuoteI would think it would be more effective to simply extend the existing stabilizers another inch or two.
It wouldn't. Canopy Aerodynamics DO NOT parallel aircraft aerodynamics exactly......
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You're not as good as you think you are. Seriously.
You're not as good as you think you are. Seriously.
-- yeah, more drag with no benefit, as I said, it's a gimick, and that may be my opinion, but a lot of people with more talent and experience than you agree with me.
Methane Freefly - got stink?
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