RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

Hello fellow scratch builder,
I'm new to rc universe and would like to chat with others who use pencil, paper and good sense, but are a little crazy when it comes to designing airplanes.cratch built CL planes and have recently started on the RC planes. My designs look great but I'm not all that up on the engeneering side. I need to talk with others on this subject.
stevefyttvll

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

Updated link from NextCraft™ - ( Mike James )


I'm completely out of the fabrication business, but am now taking the time to produce some tutorial CD's. More info, including all the previous content on my site, can be found at http://homepage.mac.com/mikejames/ne...dbuilding.html

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

I would like to build a plane that has not been created yet for a .91 duct fan. I have downloaded scale drawings from a russian site of a F-5 a,b, e, and f.
now what do I do? I have downloaded a cad program called cad I from the parkjets website. Please email or direct me to what I need to do next. I apprecialte all of your help. T

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

tsmith,

I suggest that you take the drawings that you have to a shop with big copying machines and get them blown up to the size airplane that you want to build.

At this point you can proceed with pencil and paper or CAD.

If I were doing it in 2D CAD, I would then take the drawings and draw station lines on the fuselage, top view and side view. Then, you get you ruler and vernier caliper and measure x distance to station line, top y distance, bottom y distance. Make a table to record these dimensions. If you are using CAD you input the x-y coordinates for each of the stations for both top and side views. This may sound terrible but it won't take that long. Then, you draw straight lines and curves (splines) between each of the coordinates.

Looking at your drawings you don't have y-z sections except for the front view. So, you'll have to make these on your own guessing at what the section should look like.

When determining the geometry from you drawings, you need to break it into pieces, like wing, h-stab, vertical fin, etc. You may even want to break the fuselage into sections.

Some of the folks that use 3D modeling programs may take a slightly different approach, but you can't get around dealing with the details of the geometry that has to be extracted from the drawings that you have.

Finally, this is a very complex airplane, so you may want to do something simpler...even if only for an exercise....to learn your CAD program. Learning to use CAD is no small thing...especially if you use a program that follows the command type data entry of AutoCAD. Personally, I use Ashlar Graphite which is much simpler and more intuitive....but way too expensive for normal modeling pursuits.

It would be far simpler to get your full size copies, trace over that with velum drawing paper, then do all the crossection geometry manually.....to make your formers, etc. On the other hand if you goal is to learn CAD....go for it.

Another approach would be to use your two view drawings to make a foam model, which can be carved to shape, blending between parts of the airplane. From this you could cut it into sections to get the geometry for formers...or if you want to make a molded/composite fuselage,you can use this as the starting point to make your plug, from which you make a mold, from which you make parts....but way too much trouble for a one-of airplane.

Cheers,

Ken B.

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

Just take the plunge. CAD may be easier than you think....spent hours asking questions without doing and then, once i decided to get the trace and all done....it all happened much faster than I could have imagined.......

I have used those raster to vector converters....results were not too desirable. I started work on this about 8.00 am this morning and by 10:00 am, I was done...this far. Makes me wonder what took me so long -- cold feet from over analyzing the advise and responses here???

Eventually, I plan on smoothing surfaces out after I have "skinned" this cat. The effort here was minimal so if anyone is interested in the .DXF files up to this stage....i'm willing to share. Beware though that I have not verified how smooth the contours are after skinning....you'd have to do that yourself.

I will be going further to add all the details in CAD to ensure everything fits and is at the proper location before I even cut wood. I intend to have working flaps/slats so if anyone has details of these structures (especially the flaps and how they pivot), please share with me and I'll be forever grateful.

Thanks.......S

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

I have been playing around with Turbocad Learning edition (it was the free version they gave away on line up until last year, I think it is actually v5 or 6) and will re-post a question asked previously but still can not figure out. I have some bitmap and other files I would like to drop into Tcad LE to trace but for the life of me can not get it to work. There is an "insert file, picture" option and it even specifies BMP files. When it comes in there is a small box of black and gray pixels witht the file title. If I double click on it it opens in Paint (it is an Ole object when added) but if I try to scale it up by dragging an edge or changing the x,y coords it just goes blank.

I have also downloaded A9cad as it was free but it is just differnet enough from Tcad that I hesitate to jump. I do have a regular job after all and little time to play with these things.:D

Any advice out there?

Eric

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

From your posts I can see there are some old hands at drawing plans. I'm not much of a draftsman and CAD software is out of my budget would any of you have a set of plans for a Ryan SC-W sometimes referred to as a Ryan SC145? I'm looking for something in a .40 to .60 2 cycle size.

Thank you!

Mike

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

Thanks for this great thread. I've been drawing plans like Dicknadine for a while(okay, maybe not as long as he has.[I'm only 18.]), but I've taken the plunge into CAD with TurboCAD v.4.(the free version) I've spent maybe an hour(at the most) playing around on it, and I really didn't get the whole thought process behind it. I still don't entirely, but this thread has really helped. So thanks to all who have contributed.


Sincerely,
Woops:)

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

I hope this thread is still alive, because we were just getting started. I need more info:D got CAD for Xmast and now I need guidance with it.

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

What did you buy? I have TurboCAD Pro 11.2 and by far the best source for help, beside online help and the manual is the TurboCAD User Conference. Those folks really know what they are doing with TurboCAD. Several things I thought were bugs turned out to be me not understanding how the program worked (and that was just from searching the forums. Another problem that almost stopped me is now history thanks to insight gained from a question I posted. Now I'm productive. Not FAST, mind you, but my 3D model is progressing.

Maybe there is a forum just for users of your CAD software.

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

This is clearly not done yet but I have gotten so excited about progress that I had to post this. I think I now have the hang of it and will be going back to ensure all meeting points, intersections etc are really smoothened out.

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

I am going to be building a plane off of plans for the first time, I'm wondering if anyone can tell me what I should expect? Thanks!

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

what kind , how big and whose plans, what power???? dick

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

heres a little somthing i was just messing around with on solidworks.

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

Hi, still messing round building my second plane at the moment. But keen to get one drawn up in 3D. I've got some plans off the net, but it seems none of them ever have the lines actually joining, so I can't import them into the 3D solid modeller and extrude them.
I'm keen to model a P51 Mustang or an Extra 330 (? or some kinda extra) but how do you work out what size balse you should use and what do you use as Airfoil sections ? I've tried to copy some from paper, but the plot always end's up too rough. The line thickness on most plans introduces too much error.
Would appreciate some guidance.

Cheers.

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

I have a 3D model of the 300 built using Form-Z. Not totally accurate as it is also based on 3-views. However I can scan actual aircraft and you would have to email me concerning solutions.

Wendell

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

sorry I can't help you too much, as I am not a computor person. my experience goes back to the 1930's. the good old days when we bought a kit for 10 cents and it was one a day as long as there was grass to cut or snow to shovel for the nieghbors. in addition to the rest of my carreer as an auotmotive and aircraft draftsman and engineer, pre computor, few years military and 4 years of college didn't help the model activity too much. suggest that you look at a lot of plans for sizes that they specify for the various wing sizes and types of planes. dick

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

to whom it may concen: i am try to scratch build a b-25 mitchell and i have a freind of mine that has a cnc machine that would help me make the most important parts of this project the wing rib formers,i should tell you what kit it is. It is a royal products B-25 mitchell (maratuka),the thing that i need to know is what is the airfoil design?the wing is 70"wide if that helps ,i did some research on some sites and the real one has a S3012 air foil so i don't know if that would follow suit to the kit size.so if anyone can help me i would greatly appreciate it. you can e-mail me at [email protected] thanx much.

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

Can anyone tell me how to determine the CG of a Delta Wing aircraft. I am building an F-18 with twin Fan Ducts made from Foam. It is 4 'Long and the wing span is 3 ' wide. Is there a formula for deterimining the CG for a delta wing aircraft and can someone let me know how to calculate the CG. Also I have strakes on the aircraft are they also included in the calculations. My E-Mail address is [email protected]

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

Hey guys, looking for some help.I tried to put a 22cc gasser on the front of a telemaster, couldn't get it to balance- even shortened the nose - no help.So I put a .75 on the front and called it good.
Still want to build a gasser, this time I want a pattern plane.going to use the same incidences as a sig cobra because I like the way the plane flies. Any advice on the wing span and total weight? I would like to go with a tapered wing{I think they look better} Or am I expecting to much from a converted engine?

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

I should add that you can get a free copy of autodesk inventor if you are a student from autodesk.com

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

Hi there ,,,just a silly question but very relevant to most r/c builders or at least the ones I know ...... my problem I go to Mike James page and all I get is error message ,,, I went to a page called www.whatsnew.com and it has one or two nice plans there I,d like to try the catch is they are in dxf format so I go to internet to find program dam hopeless exercise that was: question how do I open these plans, I,ve now got 3 programs downloaded and still can,t get at plan was going open and copy to C D then take them down to photocopy shop and print out, I,d never heard of CAD until a couple of years ago cheers Paul [email protected] my email if you can would very thankful as would really like to try the ugly stick tail dragger for camera craft

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

just checked the above web address its www.plans.rcmodell.hu/whatsnew.com

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

Hi Starwoes,

I worked on F-14A s while in the Navy in the early 80's. (VF-1 Wolfpack stationed at Miramar) Primarily electrical systems which affect all aspects of the aircraft. The Tomcats flaps are fowler flaps. The inboard flaps roll down small tracks when extended. There is a small panel running the length of the wing, hinged on the wing surface, that then drops down to cover the gap between the wing structure and the extended flap. This "door" was controllable from a thumb-wheel on the joystick. This system was used on landing approach to dump lift enabling the pilot to maintain glide slope. The pilot would roll the thumb-wheel and the doors sealing the gap between wing and flap would open proportionally. Air from under the wing would then flow up through the gap made by the door and join the air stream over the flap and the aircraft would descend. Keep in mind landings are made with a high AOA.

The outboard flaps were hinged at the trailing edge of the wing and would be deployed in flight as "Maneuvering Flaps". The Tomcat had no conventional ailerons. Roll control was through spoilers and use of the stabilators. (Stabilizer/elevators). In my opinion, for a model, stabilators should work just fine.

Craig.

RE: Scratch Building, Aircraft Design, 3D/CAD FAQ
 

I hope I didn't miss something, but a predominant assumption seems to be that a single software program for going from concept to a functional 3D aircraft. Do we really need to have a separate software program for each of the following?
form design = CAD/MODELING
lift+propulsion surfaces = technical airfoil coefficient stuff
engine+control system = ?
aircraft flight handling characteristics = flight sim
graphics = paintshop pro, corel draw, etc.

The graphics area is understandably specialized, but what about the rest?

Is there a particularly good (RC-small aircraft sized) aircraft design program for
ease of use
moderate learning curve
functionally powerful yet user friendly

I'd like a program for designing new aircraft design. Seems like if you do a good job with flight modeling (wind/fluid dynamics), your most of the way there.

Man, it's been a long while since I've posted here. Good to be back. I can't hardly believe how fabulous these forums are slicked out!!! LOVE IT!