Re: [RCSE] CF on spruce spars
The Kevlar tow that I used is roughly an eighth inch wide. The tow is basically a bunch of parallel fibers that are not bonded to each other. While wrapping the spar, I have to take a little care to spread out the tow and not get twists in it. Near the center of the wing, the wraps should basically be continuous, i. e., touching each other. Less wrapping is needed in the outer sections. On my Majestic I wrapped the entire spar with nearly touching wraps. Regards, Dick -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-315FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 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] New experiences and questions
Hi Vince, A few years back, I became intrigued with high-start launching and began to look at how to optimize a launch. My ruminations have been included on the Charles River Radio Controllers web site: http://www.charlesriverrc.org/articles/design/dickwilliamson_histartphysics.htm To translate between the table in CRRC article and the tubing supplied by Mark Mech and NSP, I have created the following table which I hope survives transmission via email without screwing up the formatting. Tubing sizes are listed in order of increasing cross section. CrossInsideWall CRRC Mech NSP section dia. (sq. in.) (in.) (in.) 0.024 1/16 1/16hand launch- - 0.025 1/83/64 - - upstart 0.037 1/81/16 2 meter2 meter - 0.049 3/16 1/16 - - M 0.064 1/83/32 - comp 2 meter - 0.074 5/16 1/16- - standard 0.098 1/81/8 standard3 meter - 0.101 1/43/32 - - L 0.138 1/87/16heavy duty - - High starts work nicely, especially with some head wind. However, you need a strong arm to launch a heavy plane. Regards, Dick The end of the soaring season is close here in Ohio, and the sun was out this morning. I had previously test launched my newly acquired 150" Aquila XL off of a histart made for a 2 meter (wimpy), but I thought today would be a great chance to try the bigger hi-start. Loaded up the car and drove to the club field. Range check OK. Walk WAY down the runway to stake down the end of the histart. I have only done a dozen histart launches in my life, and only 2 in front of anyone other than my dad and brother, so I am a bit nervous. I put about 60% of the stretch to try it out, point the nose at the horizon and give it a heave. WOW! I mostly let it do it's own thing, with very minor rudder corrections and just a bit of down elevator, it climbed in a nice arc. Don't know if that was right, but it felt good. Since I had not given it a full stretch, it ran out of pull before it had more that about 200 feet of altitude (guess) I did a lot of lazy circles (sun hid behind the clouds, and no thermal activity to be found with my meager skills) Landing was great, and the next launch was with full extension of the histart. Very impressive launch. I think that it was nearly over the stake before the line pulled off the hook. I played around, going upwind hunting, but there was no sign of lift, so I was back down in short order. 4 times in my RC career I have specked out my birds (Zagi wings and Dads 2 meter electric) so I can't wait to try it with this majestic sailplane! (plus it is bigger, so specking it will mean even more altitude!) Sorry for the novel, but I am stoked. I know that this is an ancient design, but I was in heaven. Now for the questions. Our fish scale said I had 25 pounds of pull at full histart extension. Is this too much? Can I try for more? Without a zoom launch at the top, a 510 foot histart, and a mild headwind, am I really about 500 feet in the air? (I am trying to come up with real world estimates of altitude) Does it sound like I am doing anything wrong or could do them better? Our club is mostly nitro, with a growing electric presence, so there was not much sailplane guidance available (but a lot of willing help with the line) Thanks in advance, Vince __ Yahoo! Mail - PC Magazine Editors' Choice 2005 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 -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-315FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 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] Foamie trainer...
Title: Re: [RCSE] Foamie trainer... Hi Les, I have been a promoter of the EPP Highlander as a great sailplane trainer. Following my advice, many beginners in our club, Charles River Radio Controllers, bought and built Highlanders. Some experts at the field tried the plane and complained that it flew too well for a foamy! My Highlander has probably been flown by at least a dozen different people. Unfortunately, the Highlander is no longer produced. As far as I know, the two EPP sailplane trainers on the market are the 72-in. Gentle Foamy and the 79-in. (2m) Defiant. http://www.mtntoys.com/ http://www.nesail.com/categories.php?subcatID=3 Currently, the Gentle Foamy is listed as "Sold Out". There are several Defiants in our club and they have proven to be good trainers. The plane flies well. I estimate that most of the Defiants have come out slightly under 40 oz. While heavy for a 2-m plane, the large wing area still allows the plane to thermal quite well. Built-up balsa tail feathes in place of the supplied Coroplast save some weight while only slightly compromising durability. The kit is well designed with one exception. The first round of kits had suspect (weak) wing joiners. Later kits may have changed this feature. I recommend the plane. Dick Hi all, have a friend who is just 'getting started'. The local club recommended a couple of good trainer planes she would find forgiving in the training, but she can't find them locally. I can see why, as I don't think any of these are still offered. Makes me wonder why they recommended them. But, using the power of THE NET, I told her I'd search and see what I could find. They planes in question: Highlander (I seem to recall these are long gone, and very difficult or impossible to find, particularly new.) TG-3 (haven't seen one of these in a long time either. Gentle foamie: I've never heard of this one. If anyone has a line of *any* of these foamie kits (particularly nib), drop me a line if you would. It would be greatly appreciated. (If not...what IS the current foamie trainer people use for training for td flights?) -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. Williamson Phone: 781-981-7857 Room C-315 FAX: 781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Re: [RCSE] Speaking of carbon spars ...
Title: Re: [RCSE] Speaking of carbon spars ... Scott Martin asked: What's the best adhesive for affixing carbon strips to wood spars? Epoxy works well. However, be sure to sand the carbon fiber first. Dick -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. Williamson Phone: 781-981-7857 Room C-315 FAX: 781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Re: [RCSE] canopy tinting
Don, You asked: Anybody have a way to tint your canopy w/o warping the plastic? RIT dye works fine. The first time I used the dye, I had the water too hot and warped the plastic. The second time, I used a scrap piece of plastic for testing. With a thermometer in the water, I kept raising the temperature and sticking in the test piece. In this way, I got an estimate of the temperature at which the plastic started to warp. When I tinted the canopy, I kept the temperature below the warping temperature and everything came out fine. Periodically, I took the canopy out of the dye solution to judge the amounting of tinting. When it looked right to me, I stopped the tinting process. Dick -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 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] Choosing Stab Sections
Title: Re: [RCSE] Choosing Stab Sections Hi Adam, You might consider Mark Drela's HT series airfoils. These are designed to have minimal dead band. http://www.charlesriverrc.org/articles/drela-airfoilshop/markdrela-ag-ht-airfoils.htm Dick Hi folks, Hoping someone can give me a hand with the particularities of proper stab/fin airfoil design. I remember understanding the concepts behind it at one point, but I've since forgotten, and would appreciate a refresher (the archives for these lists didn't help I'm afraid). I'm designing a new aerobatic model, and after some investigation have decided to try some of the Eppler sections that were presented in the March 2001 issue of S&E Modeller. When Dr. Eppler was writing about the E175, he said: http://groups.yahoo.com/group/xfoil/files/E175/ "Also, when I calculated the flapped case for the rudder chord of the 1/3 scale Swift at 50%, I clearly noticed a turbulator is necessary on both sides of the section at 35% chord. You must be aware of this fact, as I am afraid that the landing control may become very difficult without the turbulator" Well, frankly...I don't see it. I tried running a few test cases, and I see a marked decrease in the lift/drag ratio with the addition of the turbulator. Maybe my Reynolds number is too high? (300K) I've included the output I get for the section in flapped condition (6 degrees) with and without the turbulators in the following folder: Could some kind soul explain to me how best to optimize a stab or fin airfoil for a particular Re#? I'm not really interested in the full-flying variety at this point, but am willing to learn anything new if you'd like to share those concepts as well. In a related manner, I've been doing some reading on F3A pattern models, and have noticed that even though their manoeuvre speed is about 80 mph, they tend to truncate the wing airfoils they use so that the wing has a thick TE (2-3mm sometimes on a 19" chord). This apparently results in a dampening effect much like exponential. When I simulate this, I get a slight increase in max lift at a corresponding increase in drag at low Cl, but I can't rationalize an "exponential" effect. I've even heard of flared TE's on F3A rudders, which apparently help the models keep a heading on an upline (my guess is that this works much the same way as a double gurney flap). Is this a case of an airfoil actually needing a turbulator, as Dr. Eppler describes? Finally, regarding the location of hingelines, my typical approach in the past has been to run a variety of flapped conditions using a single value for degrees of deflection, and then to choose the case with the best lift/drag ratio. If this is different at for the tip and root of the stab, I've drawn a line perpendicular to the fuse centerline and aligned the hingelines to give me an overall stab planform. Is this method sound? Thanks for any help you can offer, Adam Adam Till Mechanical Engineer 403-270-9200 (ext 154) 403-270-0399 (Fax) UMA Engineering Ltd. 2540 Kensington Road NW Calgary AB, Canada T2N 3S3 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 -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. Williamson Phone: 781-981-7857 Room C-317 FAX: 781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Re: [RCSE] Tailbooms
Title: Re: [RCSE] Tailbooms Mike Fox asked: Back to doing some building again. It has been a few years and don't remember where I got some tailbooms for DLG. I am thinking it is what most DLG's are using now. Where came these be purchased? A source for a variety of high-quality booms is Rick Walba. I don't know if he has a supply of DLG booms. None are listed on his web site. [mailto:[EMAIL PROTECTED] http://tailboom.com/ -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. Williamson Phone: 781-981-7857 Room C-317 FAX: 781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Re: [RCSE] Carbon fiber reinforced spars
Title: Re: [RCSE] Carbon fiber reinforced spars Hi Wes, I am in the process of building a Majestic. Mark Drela has provided a series of suggested modifications for the Majestic, one of which is to add carbon fiber to the spars. For this 110-in.-span plane, he recommends tapered carbon fiber for the top of the spar. The suggestions are similar to those for the Bubble Dancer. Details are available on the Allegro web site. http://groups.yahoo.com/group/Allegro-Lite/ For the Majestic, the prelaminated tapered unidirectional carbon fiber strips are 0.060-in. thick and 0.5-in. wide at the center tapering to about 0.014-mils tick and 0.25-in,. wide at the tip. I purchased 48-in.-long 0.5-in.-wide strips. These don't go quite to the wing tips. For the last segment of the tips, I used 0.007-in. unidirectional carbon fiber. The bottom spar cap is under tension and needs only half the carbon fiber. For the bottom spar cap, the prelaminated tapered unidirectional carbon fiber strips are .030-in. thick and 0.5-in. wide at the center tapering to about 0.007-mils thick and .25-in,. wide at the tip. For a 2-m-wingspan plane, all of the thicknesses can be approximately halved. For one of my 2-m kits, I purchased 48-in.-long double tapered carbon fiber. Look at the details for the Allegro Lite: http://www.charlesriverrc.org/articles/allegrolite2m/markdrela_allegrolite2m.htm I have used end-grain balsa shear webs between the spar caps and wrapping with Kevlar tow in a manner similar to the Allegro construction. Also, I have used carbon fiber carry throughs as spar joiners. Mark Drela has pointed out that the spruce or basswood spar caps normally supplied with a wooden sailplane kit add nothing to the strength if carbon fiber is used. He recommends substituting hard balsa instead. What I did was to cut pieces of hard balsa the same width and thickness of the supplied spruce spar caps. Then, lengths and widths of carbon fiber were cut to match the length and width of the balsa pieces. Because I used carbon fiber carry throughs, I sanded slight depressions in the balsa where the carry throughs would eventually go. Before vacuum bagging, I slid pieces of plastic sheet into the depressions so that the carbon fiber would not be bonded to the balsa in those areas. The carbon fiber was vacuum bagged to the balsa with epoxy. Lacking vacuum-bagging equipment, a series of weights could be used to press the pieces together while the epoxy sets. After lamination is done, the edges of the carbon fiber are beveled so that the edges won't cut the Kevlar tow. I have also tried using Kevlar thread, but I prefer the tow. Because the carbon fiber will add significant thickness to the spar caps, you need to either deepen the spar-cap notches in the ribs or you need to thin the spar caps. I found that the thinning was easy to do. The balsa spar caps were laid on the bench with the carbon-fiber side down. Pieces of the original spruce spar caps were laid along each side. Using the spruce as a sanding stop, I sanded down the thickness of the laminated spar caps with the sanding bar running transverse to the strips. This procedure makes the final laminated spar cap dimensions exactly equal to those of the supplied spruce spar caps. Having done this, the assembly of the wing is just as if the original spruce spar caps were used. I used Tite Bond. CA can be used, but this adhesive adds weight and is more brittle than construction with Tite Bond (aliphatic carpenters glue) CA really soaks into end-grain balsa. Regards, Dick Building a new woodie RES and this time I want to reinforce the top and bottom spars with carbon fiber. I've been looking over the CST and Aerospace Composite Products web sites ending up with more questions than answers. I know I should use unidirectional carbon fiber, but what's easier to use: tapes or tow? What thicknesses are recommended? I don't have a vacuum bagging system, so I'll have to use old fashion phone books to weight the stuff while the epoxy dries. I did find an informational article by Bob Vixie which helped out a lot, but he didn't talk about thicknesses. Anyway, what does everybody recommend out there. Wes Gibson AMA 607029 LSF 7533 -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. Williamson Phone: 781-981-7857 Room C-317 FAX: 781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Re: [RCSE] Majestic 110" RES from Laser Arts
Title: Re: [RCSE] Majestic 110" RES from Laser Arts Dan said: I'm looking to build a RES ship to fly in our local club contests. While doing a Google search, I ran across the Majestic 110" RES from Laser Arts. Question: has anyone had any experience with this kit - pros or cons? Flying characteristics? The Majestic is a popular plane in our club and many have appeared at our RES contests. The laser cut parts fit together nicely. The wing takes a fair amount of work because cap strips are used on the top and bottom of every rib. The plane, built stock, flies quite well. It penetrates better, but doesn't float as well as something like a Paragon. Modifications can help the performance in several ways. Mark Drela's list of suggested modifications is well worth implementing. They are on the Allegro web site and in other places. The supplied fiber glass tail boom has a fair amount of flex. Replacing it with a tapered carbon fiber tail boom will provide more rigidity and also save weight. The stock plane requires a fair amount of lead in the nose ( maybe 8 oz.). The plane can be lightened a lot by using a carbon fiber boom and making an essentially new set of tail feathers out of lighter balsa. Getting rid of the metal tail mounting structures also helps. I have seen two Majestics fold their wings on winch launches. Mark's suggestions for strengthening the spar should make the wing nearly bulletproof. The spoilers are fairly small for a plane this size. The spoilers can easily be made longer spanwise. Yaw stability and rudder authority are improved by using the larger tail feathers suggested. Stability and sink while circling are improved by using the suggested modification of the polyhedral and by adding washout. These modifications take no extra work. Regards, Dick -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. Williamson Phone: 781-981-7857 Room C-317 FAX: 781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Re: [RCSE] Winch launching... thanks!
Title: Re: [RCSE] Winch launching... thanks! Hi Jeff, I am guessing that you followed the advice of Anker Berg-Sonne of CRRC. He wrote up his suggestions along with video images at: http://flyesl.com/News-y-Articles/featured_article.asp?FORUM_ID=7&TOPIC_ID=112 Dick All the negative stuff that gets posted where (some deserved Roy!) I thought I post a positive I learned right here. To the person who posted a few weeks ago, or months, whatever, about changing to my left foot for the pedal since I launch right handed. THANK FRIGGIN YOU I think he was with the CRRC. For me winching launching was a frightening experience every single time. When launching with my right foot I'd stumble backwards or otherwise lose balance 50% of the time. I approached winching each time with trepidation. I switch to standing sideways with my left shoe on the pedal and tossing the plane almost over my head as it pulls. It works GREAT! Knock on wood, now launching is no big deal. I just have to work on throwing it straight ahead (I tend to toss it to the left - sometimes WAY to the left). Really I don't recall your name, but thanks. That article was a revelation and shows again, sometimes the net is worth is weight in gold. :) Best wishes, = --- Jeffrey D. Gortatowsky La Habra Heights, California -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. Williamson Phone: 781-981-7857 Room C-317 FAX: 781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Re: [RCSE] Beginner's 2M
Hi Rense, You said: I'm looking for a rank beginner's 2M plane for an acquaintance. Has anyone any experience with the Defiant as advertised by NSP? Any other (low building) suggestions? For many years, I have been a strong proponent of the EPP polyhedral Highlander as a beginner's plane. There must be close to a dozen Highlanders in our club, the Charles River Radio Controllers. The results have been great. The plane flies amazingly well and is quite rugged. Unfortunately, the Highlander is no longer being produced. The Defiant looks to be a close replacement for the Highlander. Up until now, I have only seen a kit. Two of us in the club will be building Defiants over the next few months. My first reaction to the kit is that it is well done. However, there are a few things that I would change. The joiners at the center and at the two polyhedral breaks look like a poor design. The spar caps end up being unsupported by shear webs at these crucial breaks. The two of us plan to make full-depth joiners. In addition, the center joiner would benefit from being longer and from some tapering at the ends to avoid stress risers. From my experience with several different kinds of planes, most spar breaks occur at the end of the central joiner. In addition, we plan to replace the coroplast tail feathers with built-up balsa. I am anxious to see the Defiant fly. Reports will probably have to wait until late winter. Regards, Dick -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 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.
Re: [RCSE] Blue Hills slope soaring pictures on CRRC picturespages...
Title: Re: [RCSE] Blue Hills slope soaring pictures on CRRC p Stuart said: I cannot recall whether there was any conversation on RCSE about slope soaring at an inland Massachusetts site - Blue Hills Reservation. If anyone has soared this site can you let me know a little bit about how it was? I used to live directly across from the hill and can remember the easy hike up the hill, but that there were lots of trees to make the airflow turbulent. Perhaps you saw some photos at: http://www.charlesriverrcpictures.org/ Of the members of the Charles River Radio Controllers, I know that Ron Weissman [EMAIL PROTECTED] , Derick Veliz [EMAIL PROTECTED] and Lincoln Ross [EMAIL PROTECTED] have flown at the Blue Hills. Perhaps they can help you. Regards, Dick
Re: [RCSE] Newbie!/Spirit
raqmaninov wrote: Hello All, This forum is great. I'm learning all sorts just by reading! After years of building my kids 'chuckies' and band powered gliders from balsa, I've taken the plunge and bought myself a GreatPlanes Spirit(seems to be a good beginners choice) Did you buy a kit or an ARF. I have helped a number of club members with both kit and ARF 2-m Spirits. The ARF has two major weak points. The balsa and aluminum wing joiner fails with very little force. Replace the wing joiner with a plywood one. The stabilizer is held on by some bolts to a wood plate on the bottom. The stabilizer comes loose quite easily. The solution is to just glue the stabilizer to the fuselage. I have seen numerous crashes of ARFs from these two types of failures. If you build the kit, there are several things that you can do to improve the Spirit. These are described at: http://www.charlesriverrc.org/articles/kitmods/dickwilliamson_gpspiritmods.htm Regards, Dick -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 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.
RE: [RCSE] 3 conductor servo wire 22 ga.
Joedy, To clarify what Tony is saying, you can make up servo wiring by taking individual "wires" and twisting them together. Each "wire" should be made up of many small copper strands surrounding by an insulating jacket. You can get "solid" wire which is a single piece of copper surrounded by an insulating jacket. This type of wire tends to fatigue and break more easily than multi-strand wire. That is why the wiring on all of your household widgets is multi-strand. Once you twist the three "wires" together, go over wiring with a heat gun. This will soften the insulation and "set" the twist in the wires. Dick === >Use single strand and wind it w/ your electric drill. It'll be cheaper and >you get increased EMI noise rejection for free. > >--TR >Portland, OR > > >-Original Message- >From: Joedy Drulia [mailto:[EMAIL PROTECTED]] > >Can anyone point me to a source of the typical 3 conductor servo wiring in >22 ga? > >I have found a local source for the 26 ga variety, but not the 22 ga. >RCSE-List facilities provided by Model Airplane News. Send >"subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
[RCSE] Lost plane beeper for frequency control
The lost plane beeper/alarms are designed to look for incoming control signals from a transmitter on the same frequency as the receiver in the plane. If the alarm circuitry is powered, i.e. receiver battery is on, but senses an absence of incoming signals, the beeper starts sounding. One way to locate the plane is to intermittently turn the transmitter on and off and listen for a beeper going on and off. It would seem that the same circuitry would help avoid a shootdown. The procedure would be to turn on the receiver to check the airways before you turn on your transmitter (e.g., before launch or before ground testing your equipment at the field). With the transmitter off, the beeper should sound. If it does not, that means that there are signal pulses coming into the receiver from some other transmitter. Silence would mean that you shouldn't turn on your transmitter. Does anyone use a lost-plane beeper in this mode? Of course, additional frequency control would be required to prevent someone else from turning on his same-channel transmitter after you are in the air. Dick -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] Hard data on L/D values for models
Whenever a discussion of optimum flight strategy in head winds and sink comes up, I go back to an excellent web site that graphically ties all of this to drag polars: http://home.att.net/~jdburch/polar.htm In a head wind, you do not want to fly at the max L/D, as illustrated nicely on this web site. Dick >I can add some credibility to these numbers. > >Flying at max L/D is great when looking for thermals in relatively still >air. > >However, where flying at best L/D is really, really important is when you >are trying to return to the field from downwind in a stiff breeze, or a >howling hurricane. > >The problem is that flying at max L/D isn't optimal. Some higher speed is. >To comprehend this, it is useful to imagine trying to get back in a breeze >which is exactly your best L/D speed, It isn't difficult to understand that >you will have zero ground speed and never get home. So best L/D is some >unknown speed that is higher than max L/D. What that speed is, is totally >dependent on the specific wind speed, and is one of the most difficult >things to learn. At the F3J selection trials a couple of years ago I was >most impressed by the ability of the top pilots ability to come back home >from way, way downwind in a wind that was really pushing them back. If I had >a really good feeling for that I would be able to stay in lift much longer >than I currently dare. > >Anker -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] Speed 400 Sailplanes - Direct drive or geared?
Ron, You asked: >Can someone who is knowledgeable in this area explain why a geared >motor is (or can be) more efficient than a direct drive. If you >consider the extra weight of the drive, say 30-35 grams for a good >planetary gear box, such as cosmotec or graupner(?), and the extra >weight of a larger prop, say 5-10 grams, and factor in the extra >drag from the gearbox, is a geared motor really better than a direct >drive? I am also a novice in this area so I picked up Martin Simon's book, Model Aircraft Aerodynamics, and read the section on propellers. The starting point is the fact that a motor has a limited range of rpm and torque over which it runs efficiently and puts out a high level of power. For a direct-drive propeller, the pitch of the propeller has to be matched with the target rpm so as to pull the plane forward at the target speed of the airplane. (The pitch is the distance that the propeller slices forward in one rotation.) For a propeller with a pitch that is too high, the torque increases, the motor slows down and the propeller flails away at the air with poor efficiency. So the first step is to obtain the proper match between the motor, the propeller pitch and the speed of the plane. With the pitch optimized, there is a second consideration. Larger-diameter propellers are more efficient as described in the book. The total thrust is given by the area traversed by the propeller (a disk with a diameter equal to the length of the propeller) multiplied by the pressure differential between the front and back of the propeller. The same thrust can be obtained with either a large-diameter propeller with a low pressure difference or a small-diameter propeller with a large pressure difference. However, the efficiency of the propeller is directly related to the pressure difference. The smaller pressure difference (larger diameter) gives higher efficiency. High-rpm motors are not well matched to large-diameter propellers. Therefore, the strategy is to allow the motor to run at a good rpm while the larger propeller rotates at a lower rpm. This means using a gear box. Dick -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] Glider descent? (spoilerons)
The use of spoilerons is much like the use of upward deflected ailerons during crow. When the neutral position of both ailerons is up, as in crow, then a normal aileron input will send one aileron up and the other down. The problem is that the aileron that is deflected upward may hit the stops. One way to help out the situation is to program reverse aileron differential when in crow or spoileron mode. Programmable mixes are turned on either with a switch or a motion of the throttle stick (that controls the degree of crow or spoileron) past a certain point, e.g., 50%. Once the programmable mixes kick in, reverse differential is added. At maximum crow, the ailerons are set such that they don't go further upward when an aileron input is given. However, the ailerons go down to the neutral position for maximum aileron throw at maximum crow. This way, one wing stays braked while the other wing tip (the one with the downward traveling aileron) speeds up. In addition, the plane rolls. Dick = >Ade wrote: >> > >> If you hold full aileron in then open the brakes the "up aileron" goes up.. >> then stops at only part spoiler.. the "down" aileron then keeps going up >> until you are only slightly short of the full up aileron. > >Well, yes it does still work proportionally. > >> If I reduced the amount of spoiler then I got more aileron but less braking. >> The Multiplex works quite differently so I do get as much down movement with >> the brakes deployed as I do without them. > >I see. I just never had a problem with that on the planes I using >spolieron on. I always had very good roll control. I suppose on >the 8U I could just add in a 1 directional mix that would move the >ailerons more downward when the spoilerons were activated, but I >haven't had the need for it. > >Brett -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
[RCSE] Ezone (was ...newbie yet)
Andy Roberts asked: >what is the ezone? It is an on-line magazine devoted to electric-powered flight: http://www.ezonemag.com/ Dick -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
[RCSE] Re: Electra (was ...newbie yet)
There is already a review of the Electra on the Ezone. The reviewer stated what almost every flyer has noticed, namely, the small propeller and direct drive are a bad combination. The plane has a hard time climbing at all. A larger geared folding propeller are needed for this plane. Dick = >- Original Message - >From: "Andy Roberts" <[EMAIL PROTECTED]> >To: <[EMAIL PROTECTED]> >Sent: Wednesday, October 24, 2001 3:56 PM >Subject: [RCSE] Not even a newbie yet > > >> I always hate a question with what is the best so I will try a little >better >> question. >> >> I have yet to fly a glider, I have gotten my transmitter so I'm ready to >> choose a plane. >> Looking for something that ends up close to $100 since I have a feeling I >> may need >> to take a rake with me for the first month or so. >> >> Would you recommend an electric sailplane as a first plane or using a >> highstart. >> I live in Tallahassee Fla. So slope flying is out. >> RCSE-List facilities provided by Model Airplane News. Send "subscribe" >and "unsubscribe" requests to [EMAIL PROTECTED] > >Hi, try an electric Electra from Goldburg. I'm writing a column on the ezone >on just this subject. > > >Ric Vaughn >Marietta, Ga. > >RCSE-List facilities provided by Model Airplane News. Send >"subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
[RCSE] On-line resources for airfoil information
Joel, This is a copy of a message that I sent to someone via RCSE. Having gone through the trouble of assembling this list of sites, it might be useful to put these sites in the Model Design Section of the CRRC web site. For on-line resources, one place is to start is the NASA site that covers aerodynamics at the high-school level: http://www.lerc.nasa.gov/Other_Groups/K-12/airplane/listing.html An explanation of polars and how they affect flight performance, especially in a wind is at: http://home.att.net/~jdburch/polar.htm Martin Hepperle has a nice site. Especially see the section on Model Aerodynamics: http://members.tripod.de/MartinHepperle/Airfoils/ Performance Analysis of a Family of R/C Thermal Sailplanes http://www.rc-soar.com/tech/perfanal.htm A neat way to calculate the performance of airfoils and sailplanes: >http://eiss.cnde.iastate.edu/calcs/frames.shtml Regards, Dick -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
[RCSE] On-line resources for airfoil information
I recommend Martin Simon's book, "Model Aircraft Aerodynamics", Some of the following sites and comments are copied from an old message from R. J. Steinhaus. For on-line resources, one place is to start is the NASA site that covers aerodynamics at the high-school level: http://www.lerc.nasa.gov/Other_Groups/K-12/airplane/listing.html An explanation of polars and how they affect flight performance, especially in a wind is at: http://home.att.net/~jdburch/polar.htm Martin Hepperle has a nice site. Especially see the section on Model Aerodynamics: http://members.tripod.de/MartinHepperle/Airfoils/ Performance Analysis of a Family of R/C Thermal Sailplanes http://www.rc-soar.com/tech/perfanal.htm Glider Design Web Source http://www.charlesriverrc.org/articles_modeldesign.htm (The Charlesriver R/C web page includes several of the Mark Drela example design gliders. Drela's designs are very excellent and advanced and include a lot of supplemental engineering information difficult to come by from other sources.) Another site mentioned earlier: >http://eiss.cnde.iastate.edu/calcs/frames.shtml -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Fwd: [RCSE] Dynamic Soaring anthology
I think it was James Deck who asked: > A young friend of mine, impressed by viewing some of my videos, has > decided to make a presentation on DS for extra credit in her high school > honors physics class. I'm providing her with good footage from the videos > and she has gathered good background material for her talk. She likes John > Roe's explanation (even the non-honors students can understand it) and is > almost ready but has one question that I couldn't answer. She'd like to > tell her class the maximum velocity theoretically attainable by a sailplane > specifically designed for DS (she thinks the "tech-heads" would really like > that). Can anyone give me some educated prognostications she can use? I saved an earlier message on RCSE that may help answer her question. Regards, Dick >Reply-To: <[EMAIL PROTECTED]> >From: "Bill Swingle" <[EMAIL PROTECTED]> >To: "RCSE Soaring" <[EMAIL PROTECTED]> >Subject: [RCSE] Dynamic Soaring anthology >Date: Tue, 23 Nov 1999 13:07:33 -0800 > >I've saved several of the RCSE posts from when Joe Wurts first started >mentioning DS. I found it fun to watch the topic evolve over the course of the >discussions. I've included some of the posts below. If possible, try to get >your hands on one of the video's John Roe sold for the F3B fund raiser. The >video explains it in seconds. > >Bill Swingle >[EMAIL PROTECTED] >Pleasanton, CA > >-- >From: Joe Wurts >Date: 28 May 96 02:35:19 EDT >Subject: Dynamic Soaring > >For quite a long time I've heard about "dynamic soaring", but have almost >never really used it in any operational sense while flying rc gliders. In >fact, I've kind of filed it under the Holy Grail category. Just one of those >things that you read about. But I've now had a bit of practical experience >with it. > >One of the slopes that I have been flying at has a very pronounced "razor >back" to it (Parker Mountain near Acton CA). What is really neat about it is >that the air behind the hill is completely separated. That is, it can be >blowing 25 mph on the face, and behind the hill, it is almost calm and >sometimes even blowing softly in the opposite direction. It turns out that >this is an absolutely perfect set-up for dynamic soaring. All you have to do >is fly straight down-wind over the hill into the calm air and turn around. If >you want, when you come back over the upwind face, turn around and repeat. >With each turn, you get an amazing boost in the energy of the glider. The >first time I really played with this was with my Floyd, and on the second >go-around I fluttered the wings. The plane will take an extended vertical >dive without any possibility of flutter, so I was able to get it to above the >terminal velocity of the glider in horizontal flight!!! > >One thing that is especially wild is when the wind dies down a bit, and you >can just stay up in the normal lift in minimum sink mode. Start doing the >orbiting for the dynamic soaring and you can get up to about three times the >speed that you can when you just fly in the normal slope lift. Wild stuff. >What really gets entertaining is when you make a mistake behind the hill. The >air is a bit turbulent, and occasionally I miss the air (read: smite the >earth). This is where a good foamie comes in handy. I woulda never really >investigated this phenomena without a crash-proof plane. > >If your slope has separated air behind the hill, and you do not mind >occasionally crashing while you learn a new trick, give this a try. Caution, >I'd recommend trying this maneuver out sometime when you have the hill to >yourself. It takes a little getting used to... And a hint, the lower you go >on the downwind side, the better off you are (more delta-vee typically). > >Joe Wurts > >- >From: Joe Wurts <[EMAIL PROTECTED]> >Date: 31 May 96 01:09:58 EDT >Subject: RE: dynamic soaring > >>> With each turn, you get an amazing boost in the energy of >the glider. >>"Dynamic soaring"--- is this what seabirds do over ocean >chop/swell? Where >is >>the extra energy coming from (are you sure there is any?!)? >Using gravity to >>pick up more ground speed while in the dead zone with less >headwind=lower >drag? > >The energy increase in dynamic soaring is due to flying into a airmass that >gives you a change in airspeed "free" of charge. Lets go through an example >here. Lets assume a 25 mph wind on a slope, with the backside completely calm >(I've flown at slopes where the wind on the backside is blowing towards the >top at 1/2-2/3 of windspeed, but we will use the worse case above). I turn >downwind with 25mph airspeed, and with the windspeed, I get a 50 mph >groundspeed. I then enter the calm air, and with the 50 mph gorundspeed, I >now have a 50 mph airspeed as well. I turn around, and fly into the active >wind on top/in front of the hill with this 50 mph gr
Re: [RCSE] Book on programming computer radios
J S, You said: >Due to a severe case of CRS (can't remember sh**), does any one know >where I saw a listing for a book on programing computer radios? J S >Fleming What you are looking for is one or more books by Don Edberg. See his web site: http://www.flash.net/~dynamic3/ There are four books. The first is a general one on programming computer radio systems. A second is on the Futaba Super 7. Another on the Futaba 8U radios has been invaluable to me. A fourth book on the new Futaba 9Z will appear soon. Dick -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] high start & turnaround
Ed, I looked at the use of a turnaround with a high start and decided that it was not a good idea. Indeed, the turnaround would eliminate the weight of the rubber. However, an energy calculation indicates that the energy used to lift up the rubber with a conventional high start is a small fraction of the energy used to lift up the plane. If you use a high start with a turn around, there is the obvious problem of wear and drag on the rubber as it runs along the ground. I also looked at how to optimize a high start. My thoughts for a conventional high start can be seen at: http://www.charlesriverrc.org/articles/design/dickwilliamson_histartphysics.htm I went through a similar calculation for a high start with a turn around. The optimization assumes a fixed maximum length of the flying field. The optimization involves choosing the best length of tubing. If the tubing is long, more energy can be stored. If the tubing is short, a higher launch height can be reached before the high start pulls the plane down. When the optimization is done (on paper), the maximum launch height is very similar for a conventional high start and a high start with turn around. There is a third configuration which does look quite nice on paper. In this configuration, a traveling pulley is used on the downwind end of the tubing. The line runs from a stake upwind to the pulley, through the pulley and back downwind to the plane. The tubing used is twice the cross section of the tubing that would be used in a conventional high start. This choice provides the same peak force on the plane. With this configuration, the calculation indicates a launch height about 40% higher than that for a conventional high start. I may try this some day. Dick >Has anyone experimented with using a turnaround with a highstart. The idea >would be to eliminate the weight of the rubber by keeping it on the ground >and using the spring action of the tubing but in a different fashion than >most people use their highstart. > >In theory it seems like it should work better than the traditional way of >using a highstart for launching but since I have not seen others use this >sort of setup I thought I must be missing something. > >I would appreciate hearing from anyone that has actually tried this or know >what results were achieved by others when they did the same. I know this >most certainly is not a new idea but since I have not tried it yet I thought >I'd draw on the experiences of others that have. >Ed -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] Upstart stretch?
Dave, You said: >Using a 50 ft piece of rubber and some nylon line (50 ft ?) to create an >upstart (or mini-hi-start), what is the normal max stretch allowed. I heard >3 to 1. Is that 100 ft of stretch making the final length of the rubber >150 ft or is the stretch itself 3 to 1 making the stretch 150 ft and the >final length of the rubber 200'. Perhaps the article: http://www.charlesriverrc.org/articles/design/dickwilliamson_histartphysics.htm might provide some insight concerning your question. Also, Rich Hollyday's web site includes some data on force versus distance for surgical tubing: http://www.hollyday.com/rubberdata.htm The tubing stretches rather benignly out to 3.5 times, i.e., a 100-foot piece of surgical tubing stretched by 350 feet out to a total length of 450 feet. I regularly stretch my high starts to at least 3 times. Regards, Dick -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] servo wire
Larry, I bought some three-strand twisted wire from FMA. I also made up some myself at minimal expense. I bought wire of the appropriate gauge, fineness of inner strands, insulator thickness and color, etc. I then took about 10 foot sections of each color, tied them together in knot at one end and then clamped the knot in a vise. The other ends were put in a drill which put the desired twist in the wire. To set the twist, I then went down then length of twisted leads with a heat gun. Dick >I want to get some high quality, three strand, twisted wire for a wing servo >harness, does anyone have a source. > >Larry Scaramella >5479 Pacifica Drive >La Jolla, CA 92037 > >(858) 581-3422 >(619) 807-1653 cell > >www.mauioceanfrontrental.com > >RCSE-List facilities provided by Model Airplane News. Send >"subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] Recommend a hi-start?
Title: Re: [RCSE] Recommend a hi-start? Dean, You said: My son and I are new to RC. We have a 2M Spirit and we will be learning to fly with the help of the local club. We want to get a hi-start as the flying field is some distance from our house and we hate risking going over there and not having a means to launch. So... I'm looking for recommendations for hi-starts for the 2M class airship. Reading the messages on RCSE, you got some good advice, especially from Gordon Cottrill. I will add a couple of things. The plastic electrical reels are exactly what to use. If you buy a Pinnacle high start, the supplied reel is the same as what you can get at Home Depot or similar hardware places Visibility of the tow line can be an important factor in finding your line on the ground. What you want is some neon colored braided nylon line. I have purchased some neon yellow stuff called mason's line. Pinnacle high starts come with a bright orange line. Standard white line will soon become the same brownish gray color as the ground and will be so perfectly camouflaged that you have a hard time finding the line. The size of the rubber tubing is a major variable. For some insight on what size to get, look at our web site: http://www.charlesriverrc.org/articles/design/dickwilliamson_histartphysics.htm The "two meter" tubing is a little weak for a Spirit, but will work OK. I have a high start with exactly that tubing from Rich Hollyday. The "standard" tubing gives a robust launch for a Spirit and is a good "all-around" tubing. Dick -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. Williamson Phone: 781-981-7857 Room C-317 FAX: 781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
RE: [RCSE] zagi
Stefan, The usual sequence is to spray 3M77 on the EPP surface that you are about to cover. Don't spray the other surfaces until you are ready to cover. If you spray everything in the beginning, everything on your workbench will end up stuck to the 3M77 coated surfaces. After spraying that one surface, put on the strapping tape. Sanding the strapping tape is optional, but it does help the adherence of the covering. After putting on the strapping tape (and possibly sanding it) spray once again with 3M77. You only need to spray the tape, but you will inevitably end up spraying most of the surface. Then apply the Ultracote with an iron. Repeat with the other surfaces to be covered. While doing so, try not to get too much dust and junk in the 3M77 covered surfaces. When you are done with the covering on all surfaces, wipe off all of the 3M77 overspray on the Ultracote using Goo Gone. Finally, take out the remaining wrinkles and shrink the covering with a heat gun. The 3M77 softens with heat so that there is no problem with shrinking the covering. In fact, if you ever need to remove the Ultracote or strapping tape, use a heat gun to soften the 3M77 and you can readily peel off the Ultracote or tape. In the same vein, be careful when using the heat gun where the Ultracote has been stretched around curves or where the Ultracote is overlapped. Dick >I still have a Zage EPP lying around, that I'll start building after my >Highlander, but since it are both foamies: > >>I always cover my foamies with Oracover/Ultracover... >>Sand the strapping tape good and put on a good coat of 3M 77 I use about >3/4 heat setting >on the iron. Tack down the top and bottom completly >before you go for the smooth finish. >>lay the wing in the beds and iron/heat gun until it's nice and tight... > >Do you put a coat of 3M77 only on the strapping tape, or only at the places >you'll tack it down, or everywhere ? If there's 3M77 everywhere, it seems >hard to stretch to me, but I've never tried it (I used the _red_ tape that >came with my Zagi 400 on that one, didn't know then it could be done with >Oracover ..) > >Stefan. > -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] Paragon
Title: Re: [RCSE] Paragon Lee, If you take pains to keep the tail light and use the best light-weighting practice for construction, the balanced Paragon may come out close to 50 oz. I agree with Stan Myers. At around 50 oz., the plane is too light to fly well. The plane is so slow that it is hard to search around for thermals. Also, you better not let it get downwind in anything other than a gentle breeze. I built my Paragon with some emphasis on added strength. To balance it out, I used a 1200-mAh battery and still needed 8 oz. of lead in the nose. The balanced plane came out at about 64 oz. Even at this weight, I often add 8 to 16 oz. of ballast. Dick === I Need Advice.. I'm building a 118" Paragon (by Pierce Aero Company) If I build it per plans how much weight is required to balance CG.. Lee mailto:[EMAIL PROTECTED] -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. Williamson Phone: 781-981-7857 Room C-317 FAX: 781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
[RCSE] Definition of decalage
The Oxford English Dictionary quotes earlier aviation publications: Decalage, the difference in angle of incidence between any two distinct airfoils on an aeroplane; e.g., the main plane and the tail; or more usually between the chords of the upper and lower planes of a biplane. (from a 1917 publication). Decalage, The term aerodynamic decalage.. defined as the angle that the no lift angle of the upper plane makes with the no lift angle of the lower plane, positive when the upper plane is at greater incidence than the lower.(from a 1933 publication). While these earlier definitions were oriented towards biplanes, they include the more modern usage associated with conventional single-wing airplanes. Today, the usual definition of decalage is the angle that the no-lift angle of the wing makes with the no-lift angle of the tail (the combination of stabilizer and elevator, or the equivalent for a V tail). The decalage is positive when the wing is at greater incidence than the tail. Positive decalage implies that the wing lift is upward while the tail lift is downward. -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
[RCSE] RES Contest, Sudbury, MA July 1-2
The Charles River Radio Controllers club is holding its third annual Rudder-Elevator-Spoiler RES thermal-duration contest at Davis Field in Sudbury, MA on the weekend of July 1-2. There will be two classes, 2 meter and unlimited. Pictures from last year's event may be viewed on the club web site at: http://www.charlesriverrc.org/media/1999/9907crrc_rescontest.htm For details on the RES contest, see the events calendar: http://www.charlesriverrc.org/contestinfo/contest_00res.htm For directions to Davis Field, see: http://www.charlesriverrc.org/fields_davis.htm - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] Flying the Cape- HELP
Scobie, Cape Cod soaring sites are well covered in a summary prepared by Helmut Lelke of the Charles River Radio Controllers. His excellent summary is on our club web site at: http://www.charlesriverrc.org/fields_capecodslopes.htm One of the favorite places for slopers to stay is the Seascape Motel because of the slope right there. The CRRC web site has links to local weather and wind info. http://www.charlesriverrc.org/links_weather.htm The weather in May is often windy with warm weather winds from the southwest and colder highs providing breezes from the Northwest. If you are lucky, the winds will come straight out of the west and allowing soaring at the best sites. A rare event is wind from the east which allows sloping off the cliffs on the Atlantic side of the outer Cape. Enjoy your trip. Dick >Hey all you East Coast slopers out there... > >I have a trip coming up in the first week of May that will get me some time >at the Cape with my brother who is also a sloper in the early stages of >addiction. I have heard that cape cod has some good sloping to offer. > >I would really appreciate information about how to best take advantage of >the flying that the cape has to offer, given a couple of days or three. > >Useful to me would be: > >-site maps, descriptions, and directions >-links for the most useful weather/wind information, and the seasonal trends >for early May. >-food and lodging tips are always welcome, of course, but not so important, >unless you knowabout some kind of sandwich I just gotta have. I live to >find the perfect sandwich. > >Thanks in advance. > >Lift, >Scobie in Seattle >m - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
[RCSE] Jeff Reid's Dove questions, long
My apologies to the list for this long message, but Jeff's email address doesn't seem to work. Jeff asked: >What do you think of the dove? I have the Dove I, not the Dove II. The Dove I looks like a scaled-down open-class composite plane. The wings taper down near the tips. Everyone comments that it is a very nice looking plane. This is probably not optimum for a 2-m plane where a wider chord is more efficient at low Reynolds number. The Dove II has a wider chord near the tips and more wing area. It probably flies better. That being said, I have greatly enjoyed my Dove I, my first full-house plane. == >Is the weight listed at www.nesail.com for the Dove II actual flying >weight (26 ounces seems light for a 2-meter glider with 6 micro servos, >receiver and 600-mAh receiver pack)? My Dove I came out at 26-oz with 6 microservos and a battery around 500 mAh. The fuselage is very narrow so fitting everything in was a challenge. Instead of the "special" battery pack sold by NSP, I bought a pack in a "stick" configuration, i.e., four batteries end to end. This pack fits nicely along the bottom of the fuselage with the front end far up into the nose. The small receiver is not hard mounted, but rather it sits loose above the battery. Before choosing a receiver and battery pack, I suggest that you check out the geometry so everything fits and balances. I only needed a small amount of lead in the nose to balance the plane. >Since the listed torque outputs seems close, what would be the pros/cons >of using all Hitec HS81MG versus the suggested five HS85BB and the one >HS85MG? (HS81MG's are a bit lighter and faster, but I would assume >that unless you're using gyros, that servo speed is not much of an >issue). I used 6 microservos similar to the HS80. So far, I have stripped only one gear set. Two HS81MG servos might be better for the flaps. Being a high-wing plane with fairly narrow flaps, the tendency to hit the ground on landings is less than for many other full-house planes. === >How strong is the wing on the Dove II? Can it handle a hi-start with the >3/16 inner 5/16 outer diameter tubing? (I use 50 feet of tubing, 200 >feet of monofilament fishing line). The wing appears to be quite strong. I wouldn't try zoom launches on a winch, but you shouldn't have a problem with a high start. Your high start is probably too weak for a good launch with the Dove. I have launched my Dove on a much stronger high start and into a strong wind without any problems. For a discussion of what size high start you need, and my experience with the Dove I, see: http://www.charlesriverrc.org/articles/design/dickwilliamson_histartphysics.htm I did have problems with the wing tips breaking off at the polyhedral joint. A couple of strips of fiber glass over the joint solved this. Also, the two-piece wing gave me some grief, so I permanently joined the wing halves and fiberglassed the joint. I think that the Dove II comes with a one-piece wing On the Dove I, the rear wing hold down is two nylon bolts that go through the very thin rear part of the wing. This part of the wing broke easily whenever the wing tips hit on a landing. I moved the rear mounting point forward to a beefier part of the wing and eliminated the problem only to encounter another. The fiberglass fuselage would crack around the mounting points when the tips hit. My final solution has worked very well. I use a single hold-down bolt and line the wing saddle and underside of wing with rubber and sand paper so that the wing is quite secure when flying, but can rotate if a tip hits the ground. This solution was inspired by observing the construction of a Mantis. = >How strong is the fuse on the Dove II...do the 2-meters fly in >contest where skegs and "dork" landings are used? Is the Dove this >type of contest glider? The fuselage seems quite strong with the exception of the wing-mounting issue discussed above. I haven't flown the plane in a contest, but it would probably do quite well in light winds. == >Last Dove question...the Dove is pretty light... what kind >of winds can it handle? Would occasional slope usage be risky >for this model (local slope winds range from 8 to 25mph, but >10 to 15mph is the normal range). Despite its light weight, the plane flies reasonably fast so it can handle reasonable winds. Winds up to 15 mph are probably OK. The narrow fuselage and wing-mounting design make it difficult to add ballast for windier conditions. I would worry about crash landing the plane in aggressive slope situations. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory
Re: [RCSE] EPP "floaters" (?)
Paul Koissner asked: >I'm thinkiing of getting a floater for my nephew this summer. >Normally I think WindStar or Gentle Lady, but now I'm seeing EPP >floaters with DiHedtral. > >I'm gonna go out on a limb here and venture a guess that the EPP >floaters don't float as well as the built ups, trading off durability >for floatability. >What's the scoop? = A 2-m MAD Highlander is a great EPP polyhedral. It weighs nearly the same and flies about as well as my 2-m Spirit. EPP is not as stable as balsa so I have to periodically check and correct for wing twist on the Highlander. Durability is great! Dick - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] First Hand Catch Glider - part 2
Jeff Reid said: >By better performance, I just meant sink and glide ratio, not >more speed. The Dove II at www.nesail.com sailplanes 2 meter >section is the type of glider I might consider... it would >be a better TD type glider, and allow me to learn how to >hand catch (assuming with flaps deployed it flies slow). > >Or I may just end up getting a true HLG sized glider. Jeff, I would recommend a true HLG. I have a Dove I which will slow down with the flaps, but I don't usually try to hand catch it. When I fly my HLG Chrysalis, the normal flight speed is fairly low and the plane doesn't weigh much. That makes hand catching a joy. Dick - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] Aileron/Rudder mixing
Rodger, You asked, >When using A/R mixing, can you still use rudder independently? >also I have a futaba 6 xa, not with specific sailplane programsbut >programmable...for example if I wanted "Crow" for landing, would it still be >possible? during crow, how are ailerons functioning? Are they full up and >flaps full down, and are you controlling yaw and roll with rudder alone? = I have a Futaba 8UAF, so I can't intelligently comment on what you can do with the 6XA. "Crow" or "Butterfly" is available on the 8UAF. Don Edberg's book on the 8-channel radios describes how to do the set up and why the controls need to be set up certain ways. He may also have suggestions on the 6XA. With A/R mixing, the right stick gives the programmed amount of rudder coupling. The left stick can be used to add to the input giving by the right stick. Thus, more (or less rudder) can be added by manipulating the left stick in addition to the right stick. Note: when you have trims, along with multiple switches and levers manipulating a control surface through programmable mixes, the effects of the several different inputs is additive. They don't override each other There are special considerations when the plane is in crow. Because the plane is moving slowly, the ailerons are not as effective. You need to rely more on rudder control. On the 8UAF, the mixes can be set up such that the "throttle" stick which controls the amount of crow is linked so as to provide extra A/R mixing. Once the throttle is beyond about half way, the A/R mixing is increased. When in crow, the ailerons go up as the throttle stick is moved, and the flaps go down. The maximum deflection (trim position) for the ailerons is in the range of 20 deg. The maximum flap deflection is close to 90 deg. When the ailerons are raised, furthering raising of an aileron by using the right stick may not be possible without hitting the stops. Also, the interaction of ailerons and yaw can be reversed at large deflections. The strategy with the 8UAF is to use programmable mixes such that an aileron is not allowed to rise when there is a lot of crow. Only the downward going aileron moves with the right stick. When the aileron is lowered, drag is reduced and that side of the wing speeds up. This is the opposite of the normal adverse yaw when not in crow. So both ailerons and rudder are controlling yaw, but you rely mostly on rudder at low speeds. Regards, Dick - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-0122 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] MAD Highlander?
>Where does one get the MAD Highlander? >Tom The web site is: http://www.madaircraft.com/index.html Regards, Dick - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Dr. Richard C. WilliamsonPhone: 781-981-7857 Room C-317 FAX:781-981-5793 Lincoln Laboratory Email: [EMAIL PROTECTED] Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02420-9108 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
