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Designing a plane, wanting to do so in Draftsight

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Old 01-18-2014, 10:18 AM
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flyingagin
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Default Designing a plane, wanting to do so in Draftsight

I am starting an ambitious design project for a dual build project. By that I mean that there will be 2 airplanes with very much in common. Common fuses, engine nacelles and the root sections of the wings with a common plan form (but different airfoils). One to be RC and one to be CL (a rather large Cl).

I have made two 1/2 scale drawings the old fashion way with pencil and paper. But I would really prefer to use Draftsight. I have installed it and downloaded the GETTING-STARTED-GUIDE, some videos. Still struggling to define the drawing boundaries.

The plane(s). Tri motor bi planes. 78" upper wing span 72" lower span. 10" chords for a total of 1500" square. Power three .25s two strokes.

The drawings I have made are really crude as I could not scan anything that big and the only way I could take a picture was to trace over everything with a felt tip marker.

Setting up my drawing boundaries in Draftsight is giving me fits.

Well as crude as the drawings are I will post them. This design is going to under go some major changes.

Ken
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Old 01-26-2014, 05:40 PM
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Hey Ken, How are you doing?! I did what you are proposing to do. Here are my trials and tribulations over on RCG designing and building a Kraft Super Fli

http://www.rcgroups.com/forums/showthread.php?t=1956662

Ken (the other one)
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Old 01-26-2014, 07:39 PM
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Quote:
Originally Posted by kenh3497 View Post
Hey Ken, How are you doing?! I did what you are proposing to do. Here are my trials and tribulations over on RCG designing and building a Kraft Super Fli

http://www.rcgroups.com/forums/showthread.php?t=1956662

Ken (the other one)
Well Hi there Ken, Been a long time. I have seen some of your post on Roberts Pitts build (over there).

I will jump over on your link and check it out.

Recouping from back surgery. Darn stables in my back and upper rear end are rather tender. Had an implant put in this past Friday.

Ken

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Old 01-27-2014, 02:16 PM
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For starters don't try to set drawing boundries. Do all your initial work on a "world size" work plane with the parts all spread out so you don't run into other areas when selecting elements in one part. Working with CAD is quite a bit different in this way. With paper we're taught to visualize the final product and work towards that goal from the very first witness lines to the final penning in with ink. But CAD is flexible that way. It gives us the freedom to spread out and work on parts without running into other areas.

Later on work from this primary working drawing to cut and paste the parts over to a new second presentation/print/plot drawing that has a paper size that matches something real world for printing/plotting.


There's nothing wrong from working from a drawing of that sort to import the image then trace over it in CAD. But the quality of your "scan" can depend a lot on the picture you take. To achieve the maximum accuracy in the photograph you want to pin the drawing to a wall and set up the camera so it is dead on perpendicular in both axes from the center of the drawing to the center of the lens. This pretty much requires a tripod since you also want the front of the camera lens to be vertical (use a level to check) and parallel to the wall (that level set horizontal and measured to the wall so both ends are the same distance can work as a bar to set the lends of the camera against to square it up). A picture taken that way will retain as true an accurate image as a scanned image.

When imported as an image to trace over it's still only going to be a guide. Trace over it and then edit the line elements to square things up and make stuff parallel and all the rest of the good things.

Also only ever work on the one half. Get all the parts ship shape and square and such then select and mirror to produce the other side. The whole point of CAD is not to duplicate efforts. If changes are needed don't do them twice. Instead delete the whole other part. Then after you're done making changes just mirror copy them to the other side of center again.
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Old 01-28-2014, 07:28 AM
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one key rule in any sort of cad program, is that EVERYTHING is drawn to true scale. 1"=1". Set your units to inches, or mm, which ever you prefer, and go to drawing. Send me a p.m. I guarantee I can have you drawing in less than 1 hr. I've be doing this for 30+ yrs.
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Old 01-28-2014, 03:42 PM
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Wow BMatthews. I never realized I could use the drawings I had made before and trace them into cad. I had only drew them to visualize my concept. I will set them up to take a good and centered picture. They are certainly not going inot my home scanner. I knew that when I was drawing them and thought about making them at a scale that would. But now that you have explained it so well, I can just use what I have drawn. Those drawings are no where set in concrete anyway. Still areas that I do not like.

I had an ideal that I could mirror, just was not sure.

I set my units up in inches, but set up a bunch of things wrong. Since I never made it as far as my first line, no loss starting over.

I have not had the chance to spend any more time on this project since the original post. I had back surgery after that. Still rather sore. I had an implant put in my back. A SCS (Spinal Chord Stimulator).

As soon as I can pull it down from in the closet I am going to hook a second monitor up to my lap top. I can put things like a instruction PDF. or video on it. Might help. But then again I might be a bit dense to help. But then I am a stubborn cuss so I will get there.

I will pm you Chuck. I really appreciate that offer of help.

Ken
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Old 02-02-2014, 09:15 PM
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Hi Ken,
Check out You Tube. They have some really good videos on using Draft Site. I have been an Auto-Cad user for 25 years and cannot use it anymore because the program that I used is a 32 bit program and will not install with the new computers. I have been using an old IBM think pad laptop with XP on it but that computer is dieing, and I need to reload the bios information every time I turn it on. I decided to bite the bullet and learn Draftsight. I have made several drawings so far and can assure you that this program will fit your needs.
Larrykop@Aol.Com
PS! Forget about scanning anything. It is really simple to create a new drawing. The command I use more than any other is the Offset Command.
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