Re: [RCSE] Joiner sizing
With respect to the winch load values being quoted and using those values in the previously-posted formula for wingrod sizing, I'm getting some large wingrod sizes. For example, for a 2M wing, a 150 pound winch load requires a 7/16 wingrod, and a 50 pound winch load needs a 5/16 wingrod. These are hefty wingrods. I'm sure that this formula is correct, but I suspect that the winch load values tend to get overstated. 150-200 pounds is no doubt a value tha _can_ be reached with a strong winch and full-pedal zoom launches. I also suspect that a 50 pound winch load is still quite respectable and would be a strong launch by a typical sport flyer, and even 30 pounds is a good launch. I've not measured these values, but plugging known wingrod sizes from planes that have been flown successfully for years into the formula I've back-calculated these 30-50 pound winch loads. Has anyone actually instrumented a sailplane to measure the load aty the towhook on launch? I'd be interested in seeing those values. --Bill From: Joe Jan Wurts [EMAIL PROTECTED] To: [EMAIL PROTECTED], Mark Drela [EMAIL PROTECTED] Subject: Re: [RCSE] Joiner sizing Date: Thu, 19 Jul 2001 21:32:58 -0700 I seriously doubt you will see 200 lb pull on your winch. This number is probably initiated by me. We will occasionally (rarely) see this kind of load on an F3B winch. Much more frequent on two man F3J towing however. With a little bit of headwind, and some lift on tow, the line tension will grow extremely fast, frequently far faster than the pilot realizes. This is how most planes die on tow. I'd rate the 200 lbs case in the 99th percentile, assuming that you have your plane set up well for launch (most people have very conservative launch set-ups, which ends up precluding the high launch tensions). I end up designing my planes for the 200 lb load case, and in fact, design for deflection limits rather than plane failure. By my calculations, the Icon gets to the 200 lb case at a little bit over 40 ksi compression max. on the upper spar. Using the 100 ksi number, this points to about a 500 lb line load failure case. Designing to failure at 200 lbs will get you an airplane that is pretty flexible on an energetic tow. All that said, for F3B, the dead air line tension gets to only 50-60 lbs, and in mild headwinds, about 100 lbs. Still, one thermal on tow and the tension can quickly build towards the 200 lb number. Smaller airplanes don't have this issue nearly as much due to line drag losses reducing the power available. joe RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] _ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
Re: [RCSE] Paint Sprayer Recommendations?
Where can you buy KB Superpoxy I would like to try this. Thanks, Gary Legerton - Original Message - From: Bob Johnson [EMAIL PROTECTED] To: Jim Miller [EMAIL PROTECTED]; soaring [EMAIL PROTECTED] Sent: Wednesday, July 18, 2001 9:16 PM Subject: Re: [RCSE] Paint Sprayer Recommendations? Jim, I've been using a Binks Model 15 Automotive Touch-Up spray gun to spray epoxy paint and really like it. Three size nozzles sizes are available and I use the smallest diameter. For spraying KB Superpoxy, I mix one part pigment, one part hardner, and one part thinner. Spray with adequate ventilation and use a good quality mask. You will probably need to purchase an air compressor that will supply a larger volume of air. Regards, Bob Johnson Fond du Lac, WI I've seen recommendations here to use an automotive touch up spray gun for applications too large for an airbrush. Anyone have specific brand or model recommendations or are they pretty much all the same? I've got a piston compressor for my Aztec airbrush. Will this be adequate or will I need to get another compressor as well? tnx jtm RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
[RCSE] BSS Mid Am Contest
The Bluegrass Soaring Society will hold its annual Mid-America Soaring Championship on August 25th and 26th, 2001 at Jacobson Park in Lexington KY. This contest is also part of the Ohio Valley Soaring Series (OVSS #6), following the DARTS contest (August 11 and 12th). The CD's will be Frank Foster (Sat the 25th) and AJ Bhattacharyya (Sun the 26th): Pilot registration will begin at 9:00 AM and flying will begin at 10:00 AM. and we hope to finish by 3:30 P.M. on Sat and 3:00 P.M. on Sunday. We will be flying 3 classes, namely, Unlimited, Standard and RES, with the format being same as last year, i.e. open winch. Lunch and drinks will be provided on Sat the 25th, compliments of the BSS. 1st to 4th place trophies will be awarded in all classes flown, with an overall trophy for the highest total score from both days. Saturday's festivities willl be followed by dinner at a local restaurant (venue to be announced later). Come one, come all. AJ __ Do You Yahoo!? Get personalized email addresses from Yahoo! Mail http://personal.mail.yahoo.com/ RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
Re: [RCSE] FVK K-2
In a message dated 07/20/2001 8:55:11 AM Central Daylight Time, [EMAIL PROTECTED] writes: Can someone point me to a website for a dealer that sells this plane? It is listed on Fatlion's site but the link goes to a netmeister page that says that this site is not on their server. Thanks, Joe Gullett Spring Hill, Tennessee ChicagoSky1.com might be a good bet, although Rich may be careening his caravan over to the nats even now... Bill Wingstedt RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
[RCSE] BSS Mid Am Contest
Guys: Info about the upcoming Mid-Am contest, hotel info, driving directions to Jacobson Park etc can be found at: http://ourworld.compuserve.com/homepages/bluesoar/. AJ __ Do You Yahoo!? Get personalized email addresses from Yahoo! Mail http://personal.mail.yahoo.com/ RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
RE: [RCSE] foam cutting power source
I have a surplus variac type control, new surplus. I will sell it for $28.00 plus shipping. There is a wiring diagram with it but no instructions per se. John Derstine Endless Mountain Models E-mail; [EMAIL PROTECTED] Web Page: http://www.geocities.com/scalesoar/EMM/rand.htm -Original Message- From: Tripp Meister [mailto:[EMAIL PROTECTED]] Sent: Thursday, July 19, 2001 6:58 PM To: Mark Miller; Lincoln Ross; [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: RE: [RCSE] foam cutting power source If you don't mind spending a little money (about $100) I use a variac (sp) it's basically a 5A AC variable output controler. I can put out 0-130v AC and it works great. It will power any size bow for the most part and can be used with any other AC device. The nice thing about it is it's a closed system with a fuse so you really can't do much damage to yourself or the transformer. -Original Message- From: Mark Miller Sent: Thu 7/19/2001 6:22 AM To: Lincoln Ross; [EMAIL PROTECTED]; [EMAIL PROTECTED] Cc: Subject: RE: [RCSE] foam cutting power source I use a old large Lionel train transformer. It's the big cubic one with the two lwvers on the top for you train types out there. All I do is adjust one of the handles and it adjusts the power. It also has many different taps for different power outputs. I have had it since I was a kid (I'm 48) and it and I are still going strong. Cheers, Mark Miller http://www.isthmusmodels.com --- Lincoln Ross [EMAIL PROTECTED] wrote: I've used a power supply kit from Aircraft Spruce which has a big transformer and a dimmer switch. Cost me $25 or so some years back, and last time I checked they still had it. Had to add a little resistance to use with .020 music wire and about 28 bow, so plenty of power. (www.aircraftspruce.com, I think) Cutting slow is good if you have a setup which feeds the wire for you, such as a Feathercut. Stefan wrote: Please answer in public; I just build my foam cutter, and I'm looking for a power supply also. I've tried a car-battery charger and a transfo for modeltrains, and they do heat enough to cut very slowly, but not enough to pull wires at the end (I don't know the exact wording for this). I also have a computer power supply lying around of 200W, but that's the only indication it gives. Would that work ? Thanks, Stefan. -- Lincoln Ross RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] __ Do You Yahoo!? Get personalized email addresses from Yahoo! Mail http://personal.mail.yahoo.com/ RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
[RCSE] Re: Soaring in Socal
Eben, Welcome to Socal! There is some slope flying in Torrance. People fly between Avenue A and Avenue C. There are some slopes above Malibu but I am not sure where. I'll copy the list. I'm sure folks can tell you where many great sites are. At 08:29 PM 7/18/01 -0700, you wrote: David, I got your name off an old archive. I'm from South Africa, now in LA for at least 3 months, and I'd like to get some flying done while I'm here. I brought my own little wing with, and I'll buy a cheapie 72MHz set before the weekend. We don't fly on 72MHz in SA, so I only have 35 and 60MHz equipment. I know about the Temple Hill Squadron, but could you point me to any other slopes around Santa Monica or greater LA? I'm sure there must be some good sites in the mountains, maybe above Malibu? regards Eben RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
[RCSE] Re: how to make variac safe?
One of the more accepted hookups is to connect the output of the variac to the input of a 24v or 40v transformer, of sufficient power handling capacity, and then hook the hot wire to the output of the transformer. This way you get isolation and a fine vernier control of the actual cutting voltage. Bob -- Date: Thu, 19 Jul 2001 23:44:55 EDT From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject: Re: how to make variac safe? Message-ID: [EMAIL PROTECTED] I've used a variac for cutting foam for a couple years, no problems, but I'm ALWAYS very careful and methodical. Still, is there a way to add something to it that would make it safer? Keeping it simple. - Robert P. Andris 12155 Terrence Ave. Saratoga, CA 95070 USA (408) 252-5469 LSF 004, AMA 5055 RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
Re: [RCSE] Joiner sizing
--- Bill Harris [EMAIL PROTECTED] wrote: how do you calculate the winch load from the speed of the plane? --Bill The lift on a wing is: L = (.00237/2) * CL * S * V^2 where .00237 = density of air S = area in sq ft V = velocity in ft/sec CL = coefficient of lift, which during the launch is roughly 1.0 The tension in the line = the lift generated by the wings, so you can solve for V, which is where I get the 125 mph for my 2-meter plane to create 150 lbs of line tension. As Joe Wurts points out in a recent post on launch tension, a wind gust or a strong thermal will add lift. However, the Brits measuring launch tension on their F3B planes got nothing over 40 kg, about 88 lbs. This jibes with my 72 mph conjecture (for a 3M plane) based on the maximum speed at which my winch can pull in line when unloaded. Now 2 guys pulling a line in via a pulley certainly don't make the plane fly faster than 72 mph. However, if the wind up there is 20 mph and the plane is hanging there with no forward velocity, just kiting, and the line is stretchy, and there's a thermal, and the flaps are down allowing the CL to rise to, say, 1.2, and then they run like hell -- who knows? Due to the plane's inertia, the tension in the line can spike to a level much greater than that sustainable by wing lift. The line stretches in response to the increased tension. Then the pilot resolves this unstable situation by pointing the nose straight down. Let's say that there's 150 lbs of tension in the line, and that the plane weighs 5 lbs. That's 30 g. So the plane accelerates downward with an initial acceleration of 30 times the acceleration of gravity (!!!). The acceleration declines linearly as the tension is taken up, until it equals the acceleration of gravity. By that time the plane can be going _fast_ (see http://www.mvsaclub.com/zoom.htm) Now when you pull the nose up you can generate a lot of wing-busting force. Joe's layups.xls spreadsheet allows you to design for maximum load both due to line tension and to the high-speed pullout. If the plane doesn't explode, you also generate a lot of altitude. Dennis Phelan sez he has measured F3B launch altitude at about 1000 feet when everything goes just right. __ Do You Yahoo!? Get personalized email addresses from Yahoo! Mail http://personal.mail.yahoo.com/ RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
[RCSE] For Sale: Ready to Fly 10-Cell F5B (F5F) Simba Electric Sailplane
Check it out at: http://www.teleport.com/~slip/simba/simba.htm If you have any questions, email me at [EMAIL PROTECTED] or call me at 503-975-4864 between 8 am and 9 pm Pacific Standard Time. Shipping would be from Portland, Oregon. Thanks, Jay Decker RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
Re: [RCSE] Joiner sizing
Ah! Now this puts it all into perspective. And I'd not considered the wingloading that results from the acceleration and pullout in the zoom phase of the launch, and that is considerable. --Bill From: tony estep [EMAIL PROTECTED] To: Bill Harris [EMAIL PROTECTED], [EMAIL PROTECTED] Subject: Re: [RCSE] Joiner sizing Date: Fri, 20 Jul 2001 10:09:16 -0700 (PDT) --- Bill Harris [EMAIL PROTECTED] wrote: how do you calculate the winch load from the speed of the plane? --Bill The lift on a wing is: L = (.00237/2) * CL * S * V^2 where .00237 = density of air S = area in sq ft V = velocity in ft/sec CL = coefficient of lift, which during the launch is roughly 1.0 The tension in the line = the lift generated by the wings, so you can solve for V, which is where I get the 125 mph for my 2-meter plane to create 150 lbs of line tension. As Joe Wurts points out in a recent post on launch tension, a wind gust or a strong thermal will add lift. However, the Brits measuring launch tension on their F3B planes got nothing over 40 kg, about 88 lbs. This jibes with my 72 mph conjecture (for a 3M plane) based on the maximum speed at which my winch can pull in line when unloaded. Now 2 guys pulling a line in via a pulley certainly don't make the plane fly faster than 72 mph. However, if the wind up there is 20 mph and the plane is hanging there with no forward velocity, just kiting, and the line is stretchy, and there's a thermal, and the flaps are down allowing the CL to rise to, say, 1.2, and then they run like hell -- who knows? Due to the plane's inertia, the tension in the line can spike to a level much greater than that sustainable by wing lift. The line stretches in response to the increased tension. Then the pilot resolves this unstable situation by pointing the nose straight down. Let's say that there's 150 lbs of tension in the line, and that the plane weighs 5 lbs. That's 30 g. So the plane accelerates downward with an initial acceleration of 30 times the acceleration of gravity (!!!). The acceleration declines linearly as the tension is taken up, until it equals the acceleration of gravity. By that time the plane can be going _fast_ (see http://www.mvsaclub.com/zoom.htm) Now when you pull the nose up you can generate a lot of wing-busting force. Joe's layups.xls spreadsheet allows you to design for maximum load both due to line tension and to the high-speed pullout. If the plane doesn't explode, you also generate a lot of altitude. Dennis Phelan sez he has measured F3B launch altitude at about 1000 feet when everything goes just right. _ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
Re: [RCSE] Re: Soaring in Socal
Eben, There's a slope in Pacific Palisades (just north of Santa Monica) called Temescal, though I've never flown there. I understand its good, but there is virtually no landing area. In Malibu, there are no really good spots right on the coast, but there is a pretty good place called Snake Hill, which is a 3 or 4 miles inland from the coast. Lots of people fly there and the landing area is pretty good. I also know of at least one secret spot just a bit north of L.A. which is very consistant and even offers some DS. Do you know what city you will be staying in? Brett At 08:29 PM 7/18/01 -0700, you wrote: David, I got your name off an old archive. I'm from South Africa, now in LA for at least 3 months, and I'd like to get some flying done while I'm here. I brought my own little wing with, and I'll buy a cheapie 72MHz set before the weekend. We don't fly on 72MHz in SA, so I only have 35 and 60MHz equipment. I know about the Temple Hill Squadron, but could you point me to any other slopes around Santa Monica or greater LA? I'm sure there must be some good sites in the mountains, maybe above Malibu? regards Eben RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] -- _ Brett Jaffee [EMAIL PROTECTED] http://home.earthlink.net/~jaffee The Unoffical Extra 300 Home Page http://www.bayarea.net/~nathan/extra300 OnTheWay Quake 3 Server Utility http://www.planetquake.com/ontheway _ RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
Re: [RCSE] Re: Soaring in Socal
Brett Jaffee wrote: Eben, There's a slope in Pacific Palisades (just north of Santa Monica) called Temescal, though I've never flown there. I understand its good, but there is virtually no landing area. In Malibu, there are no really good spots right on the coast, but there is a pretty good place called Snake Hill, which is a 3 or 4 miles inland from the coast. Lots of people fly there and the landing area is pretty good. I also know of at least one secret spot just a bit north of L.A. which is very consistant and even offers some DS. Do you know what city you will be staying in? Brett At 08:29 PM 7/18/01 -0700, you wrote: David, I got your name off an old archive. I'm from South Africa, now in LA for at least 3 months, and I'd like to get some flying done while I'm here. I brought my own little wing with, and I'll buy a cheapie 72MHz set before the weekend. We don't fly on 72MHz in SA, so I only have 35 and 60MHz equipment. I know about the Temple Hill Squadron, but could you point me to any other slopes around Santa Monica or greater LA? I'm sure there must be some good sites in the mountains, maybe above Malibu? regards Eben RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Eben, there is a web site that has several slopes with directions for SoCal. www.combatwings.com Bob Pope Laguna Hills, CA RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
[RCSE] Manzanita Oregon
In the next few weeks, I'll be flying my small taildragger down the Oregon Coast for a few days at Manzanita beach with my wife. Wondering if anyone's doing any interesting flying anywhere nearby there on the Oregon coast, especially anywhere near any little coastal airports ( ;) ). What's the scene? Lift, Scobie in Seattle RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
[RCSE] My first buzzard soar.
Howdy! (The I'm from Texas greeting!) Last Saturday I flew for two hours and caught lots of light lift thermals that didn't get much height, but helped me stay in the air longer. My watch's battery died a few weeks ago and I've been too busy/lazy/cheap to go get a new one with the result that I really don't know how long I have been flying. I wanna get one of those talking count-down timers since I am often out there alone and I want to learn to practice fixed length flights like y'all fly in competitions. (Gotta get them landings down too!) Anyway, I did have one really good/high/long flight thanks to my first buzzard lift. I tossed the ol' skeeter on my short highstart and just as I came off I saw a buzzard circling about 40-50 yards to the left and half-again as high as I had launched. I had yet to encounter a buzzard in my flying field when I had a plane up, so I scooted skeeter under the buzzard and sure enough there was lift! We both climbed with him/her flying about 100' above the skeeter. Eventually the buzzard vectored off somewhere else, but I kept with the thermal which got bigger and stronger and I just kept flying higher and further downwind. Fortunately it was a mild 5-10MPH breeze so I didn't feel too uncomfortable going downwind. I wouldn't say I specked out, but it was small enough that I was having trouble seeing how she was flying. Another personal best height! I looked over to see if anyone was at the glow field, but it was empty. I wanted someone to see that itty-bitty way-up-there plane and say wow! However, it was just me enjoying the flight. I was so high that when I finally came back over the field I still had two or three times my highstart height on the skeeter, but I just couldn't find another thermal. That is one thing that I haven't succeded in doing that I would like to do - catch at least two successive big thermals on the same flight. I wonder if a big boomer thermal sucks the energy away so that it is hard to get a second thermal from the same area? (No parking lots, just hay fields and some woods.) I can't wait until I can build or buy a bigger plane! John Gossett Austin, Texas __ Do You Yahoo!? Get personalized email addresses from Yahoo! Mail http://personal.mail.yahoo.com/ RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
