I'm aware of this benefit, however a speed 400 electric plane might find less weight more beneficial. I agree that the thinnest sheeting should be used, considering the size of the plane.
Don't get me wrong. I DO like his design. I have designed many similar park fliers and found that, most of the time, weight was the biggest enemy for a speed 400 plane.
Probably true and I see and considered your point while I was answering. The sheeting would probably only really prove to provide more than it takes away if it was as light as possible. Like 1/32 light stock. I just wanted to point out that the sheeting can be a viable option if done right rather than an automatic bad thing. I should have presented it as the OPTION that I intended rather than implying that I thought your post was wrong. Sorry.
< Message edited by BMatthews -- 3/27/2004 2:00:47 PM >
Chevelle, I've been seeing various renditions of your drawings for this project for a while now and I must say that these latest are breathtaking. If the model, when you finally get around to it , looks half as nice this will be a world class effort.
But MAN, it's time to put the mouse down and pick up the Xacto knife dude...
< Message edited by BMatthews -- 3/27/2004 2:03:48 PM >
I am an R&D engineer for a living. I am in the medical diagnostics and biotechnology industries. The systems I develop are large, complicated, expensive and usually take years to develop. One thing I've learned over all that time, it is far easlier, faster and less expensive to throw away a dozen virtual versions that don't work than one real one. With today's tools, it is so much easier to try different things before you commit them to metal (or balsa in our case.) I am up to version NINE in the design of the AVRO model. I can't say that it will go together perfectly when I do indeed build it, it will be as close as I can get.
Honestly though. I'm ready. I've taken it as far as I feel that I can in virtual space. It's time put together some test sections and then the real thing. I don't just work on the tube though. I am building a BALSA USA 1/4 scale Pup. It's all framed but there is still a lot of things to do.
So with the weather seemingly broken, I need to finish the Pup, get back to flying, and of course, fire up the Chevelle! I hope to begin building the AVRO towards the end of this flying season.
Thanks for the kind words. They really help keep the motivation up during these long projects.
Ya know. This would make a really cute park or indoor model too. A GWS IPS motor and a span that offers up about 200 sq inches of area. Thin little arced balsa ribs over 1/8 hard balsa or spruce spars so the wings can warp easily for lateral control...
Hmmmm....
I certainly understand about making your mistakes in virtual space and there's no doubt that's where CAD really shines these days. Now that I'm sort of used to CAD (just 2D, I'm still a 3D babe in the woods) I don't think I'll be going back to pencil and paper for much any more. Even if I do get nostalgic and decide to hand do a cute little old timer or scale rubber model I'll probably rough it out in CAD first just to set the arrangement for the item placement on the paper.
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Chevelle; I (Grudgingly) agree with Bruce once again. You cannot figure out where an error may be at until construction begins.
We did four mock ups of a common little Cessna before getting something buildable. The problem many times has been in that creating the drawings is not enough. Just how do you build it then? Oft' times CAD get too accurate with parts placement, or cannot see something infeasible.
Adding in the little details to the interior may be fine. But once things get framed up, how do you access those from the outside. They may be burried down in there with a purpose, but if the part can't held with tweezers and inserted then you need to figure out a building order, or better ways of getting at the location. Your fingers were not as nimble as an employee's at the A.V. Roe company in full size.
I have some old plans which indicate the builder to drill an 3/16" hole through some frame members for the landing gear wire after the skin is applied. Then, the builder is to heat and bend the wire to some specified width and solder on some retaining washers. Can't be done with pliers, and think up in flames if heat is applied. Don't know how the kit manufacturer did it.
Wm.
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Thank you for your tips. here is way I made it:The amount of sheeting in the wing, in my belief, is the right one, because if you don’t put it, the front part will be very irregular, the covering will inlay in the holes between the ribs, and not a clean shape, a plus for a glider. The very narrow space between ribs, give the same advantage, but as you say, maybe a couple less give a light weight plus. The name of the glider is “Elektro-Reflex”, and I can say I’m very happy with it flight. Nice thermal flying, and 20 minutes in the air is a norm. About the dihedral, it was corrected in the next one what build a friend of mine. Mine is with this very low dihedral. But the rudder response is very good. The only problem is that the “Elektro-reflex” is a bit instable, but I keep flying it in this way , and it newer has had a hard landing or an uncontrollable flight. Thank you for all your nice comments. It is very pleased for me. And of course, sorry for my poor English!!
Certainly CAD can't get you 100% there. There will always be things learned in the building process that can't be worked out in CAD. My project will be no exception. I do however hope to build just one prototype, not four, before I have verified the design.
The beauty of 3D CAD is that it really helps you work out even assembly issues. You create parts and then assemblies just as you would in real life. (At least I do.) There were many things about the design that changed because of assembly issues.
The most powerful example was with weight. SolidWorks gives me the CG and the total weight. My original version was much too heavy. With design changes and moving the batteries and other stuff around, I have the weight at a respectable 12lbs. I expect the actual materials to be slightly less because of the types of materials used in the CAD model. However, I did not account for glue or fittings. In the end, I suspect that it will be a wash and the plane should come in pretty much at 12lbs, all up, all in. This would be much to difficult to do manually (at least for me) and it is far tougher to take weight out after it is built.
But your main point is well taken. Sooner or later, it needs to be built to catch everything. It all doesn't count until it takes flight and comes back in one piece.
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Chevelle,
I definitely agree with your design methods. Build once, not four times... sounds funny but it is very true. Especially with a complex design. 3D CAD is a big plus... a lot of the 2D guys are missing out. Plus, electrons are cheap.
Are you using photoworks to produce those images?
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3D saves me a ton of time, balsa, and glue.
When it comes to drawing plans and cutting parts, I still do it on vellum. But for coming up with and tweaking a design, 3D lets you quickly ask a lot of the "what if...?" questions, move internal equipment around, and even try different paint schemes. I'd much rather tweak a 3D model than to draw and build each revision. It's just a matter of familiarity with whatever software you use. Once you can stop thinking about which button to push, it can be a LOT faster than other methods.
Chevelle; I (Grudgingly) agree with Bruce once again....
Grudgingly?????? I can see the pain that caused from here... LOL
Well,I (grudgingly) agree with Coos It's not the drawing per say as he says but rather the process of frabrication and order of work that may find you in a grinder. CAD can show a finely detailed part sitting inside a cage of other structure and show that there is no conflict in fitting but it may be that in the actual physical build it's not possible or practical to build it that way or insert the subassembly later. It's a classic "you can't get there from here". That's one area that I rack my brain over in any project is the building and possible jigging required to get from A to B yet leave room for C to drop in and be accessible.
Kitfoxkid, that looks really nice in true life and the pic shows that there's a lot more dihedral than the 3D rendering suggests. And for what it's worth, as if you couldn't guess from my earlier comments, I'm with you about the idea of the sheeting and rib spacing. To me there are other places to save where the effect on the aerodynamics is not compromised. And while your English may be a little bit rough in areas it is very good. Certainly it is much better than my extremely basic Spanish so please do not feel you have to apologise.
< Message edited by BMatthews -- 3/28/2004 4:40:33 AM >
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Thank you for your comments, BMatthews: Here I send a couple of images more, but this time it isn’t an RC design, it is the drawing of the very well-known rubber powered “Prairie Bird”. In the first image, the bones of it. (uncovered stage) In the second, in a covered stage. Of course, all in 3D drawing, this time with autocad 2000 Best regards
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All Forums >> RC Airplanes >> Scratch Building, Aircraft Design, 3D/CAD >> RE: my drawing 
RE: my drawing - 
, looks half as nice this will be a world class effort. 
