[RCSE] OVSS #7 - SOAR Fred Fredrickson Memorial Thermal Challenge
SOAR will be hosting our 8th annual Fred Fredrickson Memorial Thermal Challenge and 2005's OVSS #7 at our sod farm field near Plainfield Illinois this coming weekend Sept 17 & 18. Long flight times, FAI landing bonus, seeded man-on-man ... and no skegs or landing arrestors! For details, http://www.silentflight.org/LSF_Base/SOARFred.html or from the link http://www.silentflight.org/LSF_Base/events.htm We look forward to seeing your here. tk P.S. One additional perk, Jim and Rhonda Bacus will be hosting a bbq at their home Saturday night, details will be available at the field. __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
RE: [RCSE] Tripping modern airfoils, and why do flaps and spoilers do what they do?
Scott - I won't answer your question about "tripping" or "turbulating" an airfoil because it really is horribly complex and situation-dependant. Here's some info in the "Aerodynamics" section of Dr. Martin Hepperle's site: http://www.mh-aerotools.de/airfoils/index.htm However, I *will* (in my own novice way) attempt to explain why the nose of the plane changes pitch when you activate spoilers or flaps: Remember that your airplane has two "centers", the center of gravity and the center of lift (or effort). One is the theoretical "balance point" for downward forces on the plane; the other is for the theoretical "balance point" of upward forces on the plane from the wing's lift (which passes through the "center of pressure" of the airfoil). See these links for more detail on this: http://www.grc.nasa.gov/WWW/K-12/airplane/trim.html http://www.grc.nasa.gov/WWW/K-12/airplane/cp.html http://www.allstar.fiu.edu/aero/Wing31.htm http://en.wikipedia.org/wiki/Center_of_pressure http://142.26.194.131/aerodynamics1/Basics/Page2.html (currently offline, but excellent) These two opposing forces rarely line up; and often the tail surfaces are used to counteract any pitching moment that the airfoil produces as it flies through the air and generates lift. Changing the camber (the curvature) of the wing surface changes the center of pressure and possibly the "effective" angle of attack relative to the oncoming airstream (think about an imaginary line running between the trailing edge of the wing and the leading edge. Now drop the flaps - see how the angle of this imaginary line has changed?). Since the center of gravity DOESN'T change, the distance between the CG and the center of pressure/effort might change and the pitching moments and forces may all change. It is these changes that must then be counteracted by changing the tail-surface deflection. Hope this makes things more clear - the web links are really great sources of info! Take care, --Noel
FW: [RCSE] Tripping modern airfoils, and why do flaps and spoilers do what they do?
Let me start a Jihad here. I have experienced what tripping an airfoil can do on the two best planes I have ever had and beleive in tripping. I have seen other people acting like it is the best thing since sliced bread after checking it out. It turbulates the air so there is less seperation thereby reducing drag. My DLG's launch higher and have less tendancy to tip stall. Now, people who think I have chasing Squirrels in my brain are goint to say things like, "I checked it out on X-Foil and it will not work, period" What I would ask of them is how many positions, thicknesses, and lengths did you evaluate? See how hard it gets! Plus, I would propose that no two wings, even from the best craftsman are identical, especially if they are bagged. You need to fiddle with it and don't expext positive results on your first try. Try it, you will like it if you give it a little time. From: "Scott and Jennifer Martin" <[EMAIL PROTECTED]> To: Subject: [RCSE] Tripping modern airfoils, and why do flaps and spoilers do what they do? Date: Sun, 11 Sep 2005 16:52:39 -0700 Bob Dodgson tripped his E214-equipped wings to achieve better performance. I'm not aware of any other sailplane designers who recommend this. Does anyone today recommend this as a way to improve airfoil performance? Was it ever a legitimate idea in the first place? If it's something that actually works, what kinds of airfoils benefit most from it? Spoilers reduce lift and pitch the nose down; flaps increase lift and pitch the nose up. This we all know. What I don't understand is why the nose pitches the way it does. Does the center of gravity somehow shift? Why doesn't the nose maintain the attitude it had before the flaps or spoilers were activated? Scott Martin Chandler, Ariz. _ Express yourself instantly with MSN Messenger! Download today - it's FREE! http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/ RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
[RCSE] "Finding a winch in Acapulco today was a killer!"
Got in late and it was warm. Then nothing but beaches and bikini's...very distracting. Looked all over that beach for a winch, or somewhere to put up something elastic other than a bra strap, but never did find a spot. Anyone have any contacts down herefor soaring that is.I got the girl thing covered...er or is it uncovered. If its Wednesday its LA. Gordy Acapulco Mexico...yep business :-( :-)
[RCSE] Re: Soaring V1 #6337
The UIUC group issued a report which covered trips. Indeed, some of the Eppler sections do benefit from being 'tripped'. However, the dimensions and placement of the trip can significantly affect the result. Following the earlier Eppler work, the Illinois group (Mike Selig and his folks) developed a number of airfoils that didn't need require trips. In many cases, adding trips didn't accomplish much other than a modest drag penalty. The recent work by Mark Drela is optimized for low Re applications beyond what was done at Illinois (hope that's not stepping on any toes but it shows in the X-Foil and wind tunnel results). So basically many of the sections used today really don't need trips and may lose some performance with them. But many earlier sections (a number of the Eppler airofils as well as the old NACA 4 and 5 digit sections) had better low Re performance (typically, low speeds) with trips. The specific UIUC reference is Volume 3 of "Summary of Low-Speed Airfoil Data", chapter 6, originally published in 1997. The reasons for tripping the airflow are very nicely discussed in this publication as well. Airfoils that don't manage the laminar to turbulent transition well are among the ones that may benefit from a physical trip. The E374 was investigated in the subject report and trips had a significant response. The SD7037 was also investigated and the trip effect was much less noticeable. Subject: Tripping modern airfoils, and why do flaps and spoilers do what they do? Bob Dodgson tripped his E214-equipped wings to achieve better performance. I'm not aware of any other sailplane designers who recommend this. Does anyone today recommend this as a way to improve airfoil performance? Was it ever a legitimate idea in the first place? If it's something that actually works, what kinds of airfoils benefit most from it? RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
[RCSE] "Finding a winch in Acapulco today was a killer!"
Got in late and it was warm. Then nothing but beaches and bikini's...very distracting. Looked all over that beach for a winch, or somewhere to put up something elastic other than a bra strap, but never did find a spot. Anyone have any contacts down herefor soaring that is.I got the girl thing covered...er or is it uncovered. If its Wednesday its LA. Gordy Acapulco Mexico...yep business :-( :-)
Re: [RCSE] Level V task completed
Congratulations Paul. Ray Hayes skybench.com Home of Wood Crafters - Original Message - From: "Barry Andersen" <[EMAIL PROTECTED]> To: "RCSE" Sent: Sunday, September 11, 2005 9:16 PM Subject: [RCSE] Level V task completed > Paul Siegel completed his two hour TD task today. Steve Sieblenaler, > Walt VanGorder and I were there to witness. > > I attempted the task as well, but found major sink at about 1 hour > and 10 minutes; aargh > > Paul completely lost sight of his AVA at one point, got it back with > spoilers out and loops. > > I had my Topaz to 2, 400 feet via Piccolario, very small Topaz indeed. > > Lots of strong up today, as you might imagine, some strong sink as well. > > > Fun toys > > Barry Andersen - CSS > RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format > RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
[RCSE] Level V task completed
Paul Siegel completed his two hour TD task today. Steve Sieblenaler, Walt VanGorder and I were there to witness. I attempted the task as well, but found major sink at about 1 hour and 10 minutes; aargh Paul completely lost sight of his AVA at one point, got it back with spoilers out and loops. I had my Topaz to 2, 400 feet via Piccolario, very small Topaz indeed. Lots of strong up today, as you might imagine, some strong sink as well. Fun toys Barry Andersen - CSS RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
Re: [RCSE] Re: Calling for F3J and TD contests
Who needs a Picolario if you fly an OLY ll ?I arrived too late for the first round of the LOFT Unlimited contest today, but had four consecutive 10 minute maxes with my OLY in the five round contest. Actually, no one in our area has needed a Picolario lately because the weather conditions have been wonderful for flying toy sailplanes for several weeks, pretty much like California around here. Ray Hayes skybench.com Home of Wood Crafters - Original Message - From: "Mike Remus" <[EMAIL PROTECTED]> To: Sent: Sunday, September 11, 2005 7:41 AM Subject: Re: [RCSE] Re: Calling for F3J and TD contests > With all that has been said a bout a Good Timer, who needs a Picolario? > > > > Mike Remus > LOFT Glider Club > Fort Wayne IN > LSF Level 5 #112 > Remember; Dreams are the seedlings of reality. > > On Sun, 11 Sep 2005 00:15:19 EDT [EMAIL PROTECTED] writes: > > A really good timer/caller will take care of the necessary things > > for a > > pilot. A good timer/caller will know what his/her pilot requires. > > If a good goat > > is needed the timer/caller will find the goat. If a good beer is > > needed that > > will also be provided. Sometimes a good swift kick in the ass is > > deserved/needed, a good timer/caller can do that as well. > > happy trails -- Rob Glover RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
[RCSE] Tripping modern airfoils, and why do flaps and spoilers do what they do?
Bob Dodgson tripped his E214-equipped wings to achieve better performance. I’m not aware of any other sailplane designers who recommend this. Does anyone today recommend this as a way to improve airfoil performance? Was it ever a legitimate idea in the first place? If it’s something that actually works, what kinds of airfoils benefit most from it? Spoilers reduce lift and pitch the nose down; flaps increase lift and pitch the nose up. This we all know. What I don’t understand is why the nose pitches the way it does. Does the center of gravity somehow shift? Why doesn’t the nose maintain the attitude it had before the flaps or spoilers were activated? Scott Martin Chandler, Ariz.
Re: [RCSE] Re: Calling for F3J and TD contests
It's also important for your timer to be someone other than yourself. I remember one of my first contests stepping up to the winch with my Great Planes Spirit, butterflies in my stomach and no timer. The winch master asked me where my timer was and I said that I didn't have one. He informed me that I needed a timer in order for the flight to count. I asked him if he'd time for me and he said that he couldn't. I found a timer and proceeded to fold the wing of the Spirit on launch. Good times, good times! Mike RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
Re: [RCSE] The right servo for spoilers
Must be nice for you to have at least one digital servo you can brag about now... 8-)) At 11:57 AM 9/11/2005, you wrote: I'm sorry, John these guys are killin' me I just couldn't take it ;-) Jim Downers Grove, IL Member of the Chicago SOAR club, and Team JR AMA 592537LSF 7560 Level IV R/C Soaring blog at www.jimbacus.net RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
Re: [RCSE] Re: Calling for F3J and TD contests
Good point, Mike. However some pilots seem to be entranced by the lady's accent on their Picolario. Jim Deck
Re: [RCSE] The right servo for spoilers
<<...and Id like your recommendations for the best micro servo for the job.>> Ok... ok... ok OK. I can't resist. ;-) If you want weaker... slower... heavier... larger... and more expensive I'd use the JR 368. ;-) Otherwise, the new Airtronics digital would be a good choice... 94761. Probably more power than you need though I'm sorry, John these guys are killin' me I just couldn't take it ;-) D __ Yahoo! for Good Watch the Hurricane Katrina Shelter From The Storm concert http://advision.webevents.yahoo.com/shelter RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
[RCSE] For Sale - Electric Ultra 120 Tug
I have it listed on RCGROUPS http://www.rcgroups.com/forums/showthread.php?t=414841#post4291436 I put this togeather for a Electric Glider Tug.I have to many projects and need to make room.I wil give you the airframe and 25% off of the new parts.All that is needed to get thi in the air is a ESC that will handle 9S lipo @ about 50 amps.Hanger 9 ultra 120 (Used)Free4 hitech HS 425 servos in the wing (new)4 x $15.00 = $60.002 Hitech HS 5245MG servo in the tail (new)2 x $50.00 = $100.00New Hacker C50 ACRO EXTRA-LONG 14XL1 x $400.00 Motor mount (NEW)1 x $30.0018-10, 19-10 and 20-10 APC props (new)3 x $15.00 = $45.003 3s3p TP 5700 packs to make 9s3p 5700 (used)3 x $100.00 = $300.00Total Price $935.00-25%your price $690.00 + shippingPaypal only please.Pic's upon request.Thanks,John Fruge
[RCSE] The right servo for spoilers
I have a Bird of Time to which I’d like to add spoilers, and I’d like your recommendations for the best micro servo for the job. I plan to use a servo for each spoiler. Thanks! Scott Martin Chandler, Ariz.
Re: [RCSE] Re: Calling for F3J and TD contests
With all that has been said a bout a Good Timer, who needs a Picolario? Mike RemusLOFT Glider ClubFort Wayne INLSF Level 5 #112Remember; Dreams are the seedlings of reality. On Sun, 11 Sep 2005 00:15:19 EDT [EMAIL PROTECTED] writes:> A really good timer/caller will take care of the necessary things > for a > pilot. A good timer/caller will know what his/her pilot requires. > If a good goat > is needed the timer/caller will find the goat. If a good beer is > needed that > will also be provided. Sometimes a good swift kick in the ass is > deserved/needed, a good timer/caller can do that as well.> happy trails -- Rob Glover
