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i have a small wind tunnel i inherited from a friend. its all folded up right now and a box of paper tubes and fans. but i have no interest in testing airfoils with it. a more effective approach would be to use software simulators like profili or foilplot but i dont really want to do that either. real world testing like what steve did is of more interest to me.
as i mentioned before a friend and i did extensive glide, speed, and and drag evaluations some years ago. results pretty much confirmed what the government sponsored tests concluded. when mentioning in discussion with dickeroo that i had photos of the plane and removeable steps he showed interest in seeing them. so i will dig them out of my friends old hard drives and post them on rcgroups. the drives are pata and my pc is sata/usb so it will take a while. heres a pic of the same plane rich and i used for those tests that i posted in the radio forum last year: maybe you can see the foam has been broken in a few places (aerodynamic testing can be a rough game. ) the steps are not shown because i dont use them anymore but i still have them and when i get a chance ill put them up too. for curiosity sake heres that thread: https://www.rcgroups.com/forums/show...2#post19933907 |
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Last edited by dave1993; Feb 13, 2012 at 05:54 PM.
Reason: photo
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Ok, even though it is said by some very prominent members that the KF airfoil just does not meet up with the performance of more conventional airfoils (no insult or sarcasm intended, I really do not want to see another argument break out ), do you guys think that the KF airfoil could be used in smaller applications such as small UAVs such as the RQ-11 Raven? Would that be a practical application or not? Also, one of the reasons I think the KF airfoil might not be as efficient is that the vortex is not being constantly trapped. Perhaps wing fences would help with that. Just an idea.
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Last edited by teflyer; Feb 13, 2012 at 09:42 PM.
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Yes, it will work very nicely. Here is one of the best examples ever seen on these forums I think:
jaron's UAV Flying Wing - https://www.rcgroups.com/forums/show....php?t=1028334 Check jaron's blog page too, he has some very interesting stuff there. He has shot some of the best aerial photography I have ever seen... Jack |
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More terrific aerial footage with Jaron's design.
Mr. Utopia has also posted some terrific videos that he shot using Jaron's KFm3 flying wing as well as Jaron's Intermezzo 100 KFm7 flying wing. Here is his blog.
https://www.rcgroups.com/forums/member.php?u=300307 Here is a long range flight he made with the KFm7 flying wing by Jaron.
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Last edited by Dickeroo; Feb 13, 2012 at 11:21 PM.
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Wow! Marlena Shaw and California Soul. That is a classic!
Great video too Dick, thanks for sharing it. And for those of you that did not know it, Dickeroo is Mr. Richard Kline himself. Yes, that Mr. Kline! If you pursue Dick's link for Mr. Utopia and Jaron's Intermezzo 100, there are some wonderful details. One of my favorites is the airfoil cross section that shows how the flat plates were arranged to create the KFm7 airfoil in an arrangement that fits with the Sipkill 1.7/10B airfoil. https://www.rcgroups.com/forums/atta...mentid=3112309 Jack |
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Last edited by jackerbes; Feb 14, 2012 at 04:03 PM.
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By the way, that Jaron layout looks a lot like the planes/rockets that Rob Edmonds (user:Edmonds) designs. This is one example.
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I guess this is a bad time to bring this up , but I never used a KF wing for Best Glide ... I always used it to stabilize the wing (stall resistance) ... Making many squirrel -y park fliers into dependable fun planes ... LAR wings especially , Deltas too ... my $00.02
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Latest blog entry: Lost plans
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Nonetheless, GP, that's a data point. The preponderance of empirical data suggests that this is one of the undeniable aspects of the KF that bears further detailed study.
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[QUOTE=dave1993;20735371]i have a small wind tunnel i inherited from a friend. its all folded up right now and a box of paper tubes and fans. but i have no interest in testing airfoils with it. a more effective approach would be to use software simulators like profili or foilplot but i dont really want to do that either. real world testing like what steve did is of more interest to me.
Dave: could you send me pix or drawings or literature from it on sizes and particularly the lift and drag measuring parts if there? |
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Quote:
wind source consists of 2 dual reversable window fans with triac control. the tunnel itself is a cardboard klh speaker box about 6' long, now folded flat. theres also a box of tubes about 1"x12" made from newspaper, most of which are twisted out of shape. theres a hole in the side opposite one wall painted flat black which must have been for taking pics. i also saw an envelope full of what looks like either incense sticks or fireworks "punk". probably used for flow imaging. there must have been a light source although i dont recall seeing one. theres another opening in the top where a wire hung from a postal scale (long gone) for lift measurements. today one of those digital scales would be better for that it seems. afaik there was never any drag testing. it was used mostly to test lift of airfoils constructed from copy paper. i dont think any had kf steps. they were cut out and glued from postscript printouts generated by a program called "plotfoil". i still have a copy of that program and was playing around with it recently. hundreds of naca files. one conclusion was for small models the airfoil shape is not important. i think he also used it for checking out profiles for full size ultralight aircraft of which he designed and built several. i have a couple folded up in the garage. personally im not a huge fan of laboratory testing, either for aerodynamics or radio. imo nothing beats the real world for gathering reliable information. |
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"personally im not a huge fan of laboratory testing, either for aerodynamics or radio. imo nothing beats the real world for gathering reliable information."
I would agree with that statement. Plenty of inventions have been successfully tested in the lab only to fail in the real world. With a KF airfoil test in either a computer or wind tunnel test, it is not likely that any forward pushing air pressure directly behind the step would be revealed unless the testing was specifically designed to do so. Computers are not set up for that aspect of testing. The KF airfoil has been shown to be less than stellar when it comes to gliding. However, it does more than hold its own in many other areas. My guess is that the KF can carry a much heavier payload than the thin Drela airfoil to which it is always compared. So, it really depends on what the purpose is. Gliding or payload. If I'm off base with the statements above anyone is more than welcome to straighten me out. |
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Last edited by Cap_n_Dave; Feb 15, 2012 at 09:05 AM.
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Quote:
Quote:
Also worth mentioning is that with "real world testing" you need a way to gather some data ... Steve's test was pretty simple, had few variables, and did not require exotic/expensive data acquisition instruments. Suggest you consider the same approach. Possibly more interesting would be some tests using actual data acquisition instruments to gather infomration of interest (pressure, temperature, etc.) but I suspect that would be confined to a rich hobbyist or a university program. |
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