Flying Scotsman 70

How does everyone here scratch build? what i mean is do you draw up plans first be it on Cad or paper or do you just cut wood and use a mental plan . I would like to know how you do it>>

SoCal GliderGuider

How to do it. Many start with a three view of the aircraft of interest. A jpeg is usually a good start. Many of the CAD programs will take a graphic in behind the drawing area. Make a layer that has a nice contrasting color and use lines, arcs and polylines to outline the aircraft and any obvious internal structures like bulkheads, ribs, etc.

Do both sides of centerline. Straighten out the outlines so the center line of the plan view is aligned with the CADs default axis and mirror each side upon the other. This will show you any discrepancies in the jpeg of the printing. Now work all lines out so you have a good side. Delete the other side and mirror the good side over. Now you have a symmetrical view to began with.

Scale your reconciled views to what ever size you want it to me and start laying in the balsa, ply, foam, carbon fiber, to build it.

The use of materials for a certain size and use aircraft is another thread.

Flying Scotsman 70

how bout OD's

SoCal GliderGuider

Original designs have to be based upon sound aeronautical principles. Depending on what type of plane you want to design and build will dictate the airfoil, surface volume relationships, movements. It's sometimes best to find an established design that you like and build variations of it.

Guess you need to provide a little more background. Your intent.

Flying Scotsman 70

Im not planning i was just curious

Gray Beard

My Feedback: (-1)

If your not into designing just go buy an RC Modeler or Model Airplane News magazine and go to the plans section, they have them on line also. Pick out A couple of planes you would like to build, the mags inform you of about how hard they are to build so you don't get in over your head. When you buy them they also come with an articial from the Mag that is A help in building, not exactly step by step but they are A big help.
What your doing this way is for the most part just buying the materials and building your own kit and building it the way you would like. That's why you will see posts stating plans built and scratch built or scratch built from so and so plans.
There are plans out there for some very different planes you don't see very often.

E-snake

My Feedback: (2)

for a good variety of free plans, go to [link=http://www.rc-files.com]www.rc-files.com[/link]. They have a lot of plans to be downloaded.

CafeenMan

For me it depends on the complexity of the design. For a simply mono-wing I just work out moments and areas on paper and then start cutting wood. If the design is too complicated to do that way then I draw as little plan as I can get by with. Normally that's for things like biplanes where I want to figure out how to place the wings, length of cabanes and such.

For a very small model where there may be a problem fitting the equipment I almost always draw a side view and top view of the fuselage just to ensure I can get everything in there.

dicknadine

its simple to say - just find a 3 vu of the aircraft and enlarge the outline to your desired wing span. weather you use pencil and paper or cad, its similair. the big exercise is what size of balsa do you use, how much, where do stringers go, how to determine to fuselage contour, it goes on and on. it all comes with experience of doing it over and over again over the years. suggest that you start learning to enlarge the 3 vu's, manually or computor program to your desired wing span size. then start looking at the plans of different planes, shown in the magizines and start thinking along those lines. formers go here, stringers needed to stiffen the structure up. on and on and on. start simple and keep going, going and going. expect lots of boo-boos and some happy days. I have learned that over the last 70 years of modeling that there is still plenty to learn. model application is NOT the same as a real aircraft, but the real thing helps a heck of a lot. heres some proof, 21 scratch design and build models hanging from the wifes laving room, dinning and 2 bedrooms and more in my back shops. dick

BMatthews

I don't do nothin' without at least a sketch to scale. Like they said the numbers count and the design must be based on the numbers so the areas have a proper relationship to fly well. Those numbers and relationships can come from the TLAR (That Looks About Right) but the ability to TLAR only comes with experience and studying a lot of other designs that came from using the numbers or TLAR from other designs that used the numbers to define their shapes.

So for a new designer it's wise to do the math or closely follow a proven design and change some shapes to make it "original".

As for structure and sizing up the parts that too comes from familiarity with past projects or other folk's successful designs.

Basically study all the magazine plans you can and download all the free plans you can and study the details and shapes. Then make your own design that is close to what you've seen.

cwesh

I do my designing on the PC now, using QuickCAD by Autodesk. It a cheap 2D CAD program but works good for what I do. ($49.99)

It really helps me with the accuracy of the parts. So far I have 26 different projects in CAD, from creating a drawing of the old Andrews TrainerMaster via raster/vector conversion to my own designs.

My latest creation, Starliner Mk III is flying. It has proven to be an excellent flyer. I will smile whenever I fly it. Also have it's bigger brother under construction the Mk IV. It is 20% larger and has retracts, where the Mk III is fixed gear.

Here are some pictures of the Mk III.

Later!