RE: [RCSE] 3 conductor servo wire 22 ga.
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]
RE: [RCSE] Digital Scale Accuracy
300g should measure any complete HLG. I think that 0.1g is sufficient precision, less than that and you don't see the differences in density of small wood pieces, more is probably wasted. Just my opinion. (Got my AllegroLE to come in at 34.7g lighter than anticipated w/ judicious use of a scale.) --TR -Original Message- From: Brad Willoughby [mailto:[EMAIL PROTECTED]] What kind of accuracy is needed for hand-launch building? Is 1 gram enough? .1 gram? .01 gram? How about capacity? 100 grams? 1000 grams? 1 grams? RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
RE: [RCSE] Foam (WAS: Fellow baggers beware)
But you bring up a question I've been meaning to ask: how does Greyboard measure up again Blue and Pink? It's a much more neutral color and feels different, so maybe it's stiffer? Lighter?. -J Here's some info I've compiled from various sources: Comp Strength [psi] Density [lb/ft^3] Specific Strength Dow HL 115 115 3 38.3 OC Foamular 1000100 3.6 27.8 Dow HL 60 60 2.2 27.3 OC Foamular 600 60 2.4 25.0 Dow HL 40 40 1.8 22.2 OC Foamular 400 40 2.0419.6 OC Foamular 250 25 1.8 13.9 Dow Blue Type IV25 1.8 13.9 Dow EPS Type IX 25 2 12.5 OC Foamular 150 15 1.4 10.7 Dow EPS Type II 15 1.5 10.0 Dow EPS Type I 10 1 10.0 Dow Blue Type X 15 1.6 9.4 Dow Grey15 1.6 9.4 OC = Owens Corning Choose your foam based on requirement: lightness = lowest density; strength = highest Specific Strength; all controlled by availability. --TR RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
[RCSE] Re: Dive Brakes!!!.are they Spoilers??
Brian asked: I am curious. If the bottom spoiler/dive brake is hinged from the back (trailing edge), then that forms a type of a scoop or pocket. How could this cause lift? The air can't exactly flow easily around the device or over the top of it... You've probably seen those powered beer cans that spin and foam up and explode or fly? They don't have a very good L/D, but basically they drag air quickly over the top--reducing pressure--and combined with fwd speed, they push up a pile of air underneath--increasing pressure--and in a cloud of suds, the thing flies--sorta. Anyway, a lift killer on the bottom of the wing does the same thing--increase pressure underneath. The flow will be all kinds of bad and the D part of L/D will go way up indeed, but there will be a slight compensation in L, and that's what everyone's getting all excited about. Frankly, the purpose of lift killers is to decrease the L/D to the point where you have a chance at nailing the target. If upper/lower surface killers are such a big deal, they will be a disadvantage because L/D won't drop as fast as a plane with the same killer area on the top surface. Therefore, these god--err CD's--who pontificate about banning them just cause they feel like it are actually doing a favor to the double-sided lift-killer flier types. While absolutely none of any of this is based in objective fact, I wouldn't be surprised if it's mostly hype and 3D windtunnel tests would show there wouldn't be much discernable difference, as long as you require all surfaces to move together. Tony Rogers Money-back guarantee on opinions provided here RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] DAW Me163 Comet
The one important thing I forgot...use servo savers! These are a bit bulky and intended for cars, but compared to digging a servo out of the wing to replace the gears, they're not so bad. I trim down the output arms to just one hole and that helps a bit. They will compress a bit at high speed, over 150mph, but at that speed a bit of reduced travel doesn't seem so bad compared with the confidence they impart. Have fun! Tony Rogers RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] My first molded part....
I'll take on a couple I'm trying to make an all Carbon all flying stabilizer mount like Mark Drella's: When you build a part like the V shaped support, 1)Do you have to mold it to final dimensions, or can you trim the part to dimension after it cures? Sure you can trim it, but you'll have to do more surface prep than if you mold to final size. Taking some off the edges is not that hard, but be aware of severing long fibers and significantly weakening things... 2)If you can trim it to final dimensions, does the vibration of some thing like a dremel tool cause delamination or weakness? Make sure the rotation of the cutter is tangent along the edge, not across it. If you hold a thin sheet flat and position the dremel tool horizontally, you will get vibration like an instrument reed which can be damaging. If you hold the tool vertically, the stock will not vibrate and will be much safer. 3)After my part comes out of my simple mold can I add the reenforcing tow as a second step? Yes (see #4) 4)If I am molding in multiple steps what precautions should I take to insure that I get a good bond in the secondary steps? Using epoxy, be sure to either pile layers upon one another only a few hours apart or clean the surfaces thoroughly between coats. Curing epoxy will put an "amine blush" on the surface which won't allow the next layer to properly grip the preceding. Wash with warm soapy water. You can lightly sand, but only after you clean off the blush. Using polyester resin, you will need to know what type you are using. Laminating resin will not fully cure, but can be recoated w/o much prep. Finishing resin has a wax disolved in it that makes an air-proof layer allowing full curing. If you use this, be sure to let the resin cure, then wash w/ something that will strip the wax (acetone, etc), then sand. 5)What do you use for mold release? Where do you get it? PVA (get the spray cartidges), mold wax. You can experiment w/ others, just consider how much your mold is worth. Look in autoparts shops, plastics shops or marine shops. 6)If I don't need a perfect finish can a use a cheaper/easier to get mold release like Parafin wax or car wax, vaseline? ? You can always try. Again, do a cost/benefit analysis. Is it worth the risk of ruining a mold that took 50hrs to make for a $10 jar of wax? Or do a cheaper experiment on something that won't be missed. Hope this helps... Tony Rogers RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] Prototyping tools and techniques
1) Am I wasting my time getting a hand coping saw for cutting hot wire templates using phelonic material If you are making one-off prototypes, you can get good results making templates from heavy poster board (like on the back of notebooks, etc). Plot out your airfoils and glue them to the poster board using 3M 77 or stick glue. Then you start cutting where the wire cut will end (TE usually) with a pair of long, sharp scissors. Keep the scissors pressed fwd all the time, esp when opening them at the end of a snip. The surface will be adequately smooth, probably better than most home-built foam cutting systems can acheive. I use 1" nails and 3M contact glue to hold the profiles onto the foam. Works well and you can make up a wing's worth of demplates in 30 minutes--then throw them out. Hope this helps... Tony Rogers RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
Re: [RCSE] Prototyping tools and techniques
As for the airfoil modeling software, there is one available online at http://beadec1.ea.bs.dlr.de/Airfoils/calcfoil.htm This doesn't use the Eppler or XFoil code, but conformal mapping to get the velocity distribution. I'm not sure exactly how accurate it is, but I use it for comparison between airfoils. You can easily copy and paste coordinates into the input window from your .cor files. Cheers! Tony Rogers RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
RE: [RCSE] 3R's Delivery Time
Well then my three weeks sans reply isn't so bad. I was concerned at first,
but the card didn't get charged for stuff like carbon fiber or Multiplex
gear (video not even charged yet), so I guess it's all on the up and
up--just in very light lift ...
Tony Rogers
Product Design Engineer [EMAIL PROTECTED]
Precision Interconnect 503/603-4750
(I am still waiting for my "3Rs" Video - over a month now.)
:'{Regis
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RE: [RCSE] One Piece Wing - Tangent
Similar question: I'm just about finished building a vac system and am thinking about bagging my first wing. How do I bag a triple taper (Shumann) wing? The surface has got to really look bad if I fiberglass wrap every transition like Olly was talking about after the bagging. OTOH, aligning all those seperate sections and beds perfectly during the bagging sounds like a nightmare to me, though much more appealing structurally. How's it done? Tony Rogers Product Design Engineer [EMAIL PROTECTED] Precision Interconnect 503/603-4750 RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
RE: [RCSE] 2 meter sailplane wanted and over
Here's a site about Roberstson Trilerons http://www.users.uswest.net/~slickraft/tritext.htm Tony Rogers Product Design Engineer [EMAIL PROTECTED] Precision Interconnect 503/603-4750 RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
RE: [RCSE] Pouring lead into tubes
Why not pour into tubes the same diam as your wing tubes. When the lead cools and shrinks, it will fit the wing tubes perfectly, with no jacketing. Just a thought... Tony Rogers Product Design Engineer [EMAIL PROTECTED] Precision Interconnect 503/603-4750 poured last night and the lead shrank in diameter enough that it easily fell out of the tubes. RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
RE: [RCSE] Re: Adhesives
Acetone: The stuff will dissolve even set CA, it is harmless to humans (unless lit on fire) and is readily available at stores that sell paint or as fingernail polish remover (just get the plain stuff as some has perfume, lotion, hormones, pheromones or other "foofy" stuff in it :) Tony Rogers Product Design Engineer [EMAIL PROTECTED] Precision Interconnect 503/603-4750 I once read somewhere about a common household chemical that disolves CA. RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
RE: [RCSE] Lightweight HLG pushrod alternatives
I use 4lb fishing woven spectra line, routed through small glass beads, for pull-pull control. It can't weigh more than a couple grams, has very little stretch, no slop and doesn't cause trim changes with temperature. Tony Rogers Product Design Engineer [EMAIL PROTECTED] Precision Interconnect 503/603-4750 RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
RE: [RCSE] Wing Spar Design
Sorry I missed the first post. Bill, sounds like you're working on a spar system similar to one I'm building at the moment. It's my first design of a "big" plane at 120". I have two spars like you say, but I placed them so that they are at 90% wing thickness so as not to compromise strength too much. This places one spar at about 17% and the other at around 42% if memory serves. The spars converge in the outer panels as strength requirements decrease. This allows me to use three panels and have two joiners equally sharing the load at the two midspan joints. These two joiners are significantly smaller than the solid joiners typically found in the center of a wing because the load on the joiner increases roughly by the distance from the wingtip squared. I have an almost solid spruce spar (well, two of them actually) 3/8" wide in the center, and no joiner to further complicate things in this already compromising area. The spar tapers by steps of 1/16" to 1/8" as the load decreases. It's still a ways from launch, so I don't know if it will work at all, but theoretically, the wing will sustain 8g--that's 36lb. I don't know if this is typical, but back engineering a couple 2m and a 100" plane gave an average value of about 6g. I don't know if this approach captures what you have in mind. If you're interested, I could fire you off the spreadsheet I used to design the spar system. It's pretty flexible and designed to work w/ the PlaneGeometry spreadsheets, but can be used as a stand alone. Tony Rogers Product Design Engineer [EMAIL PROTECTED] Precision Interconnect 503/603-4750 -Original Message- From: Michael Imsic [SMTP:[EMAIL PROTECTED]] Sent: Wednesday, May 31, 2000 12:38 AM To: RCSE Subject: RE: [RCSE] Wing Spar Design I am sorry this thread did not take off, it is a really interesting one I think. Perhaps everyone was to busy contemplating Inge's fashion sense? Here are some links I have relating to spars. http://www.geocities.com/Pipeline/Halfpipe/4579/spars.html http://www.cstsales.com/SparBuilding.htm Does anyone have any other links? Kindest regards Michael Melbourne, Australia ICQ 3481522 -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Sent: Saturday, 20 May 2000 4:03 AM To: RCSE Subject: [RCSE] Wing Spar Design Let's discuss wing spar design, and as a spinoff, the modes of spar failure. I'm specifically looking at built-up wings, strong enough to withstand heavy-pedal winching. I'll chime in more as the discussion heats up, but my initial spar design in built around spruce main spars with CF laminations, shear webs of vertical-grain balsa or ply, and possibly a ply box structure to contain the wing joiner rod. I like the idea of a secondary spar at 2/3 chord with a light joiner rod to keep the wing halves from twisting. The center of the wing panels(s) should be sheeted and 'glased, and a D-tube LE gives torsional rigidity. I'll fine-tune this the more I build, but from an intuitive view, it seems correct. I've not seen any (sailplane) failed wings, but it seems to be the stresses involved in winching would put the lower surface in tension and the upper surface in compression. --Bill RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] __ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.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]
