I currently use Cobalt from Ashlar Incorporated (
www.ashlar.com). I also use SolidWorks and a few others as needed.
I follow the math you stated, however shouldn't it be a two parameter equation as both X ad Y need to be variables? I suppose I could treat the variable s as a two element vector containing X an Y.
The big question I have is why I need to use your formula?
Also you may want to repost with parenthesis at the proper places to correctly specify order of operation. As the equation reads presently the last term is: -thickness/(1 + y'(s)^2)^(1/2).
Again I'm not quite following where you are going with the formula.
What type of differences between Aeronautical Literature and do-it means are you talking about?
I had been considering the idea of laser cutting the foam rather then hot wire. It is faster and equally as accurate.
I will consider the CNC-hot-wiring....
the real question with the Q series airplanes is what exactly high precision means.
As to today's materials use... it really gets down to cost on that one. From what I have seen of experimental composites there is a good reason glass is used. 1) It is light enough, 2) it is inexpensive to buy and use and 3) it is strong enough when proper structural techniques are used.
I would love to create a carbon fiber Q series aircraft. However I don't think the build would be popular for cost reasons. This will not however preclude me from looking into the structures and materials using carbon fiber.
In reality I think carbon fiber will be nearly be a 1:1 replacement of glass. I'll have to validate the structures that way. Keep in mind my first goal was to completely reproduce a Q-200 electronically. My secondary goal will be to create variants of it.
Foam choice is important. Admittedly I am not at a point where I am ready to worry about which foams are used as I am still modeling the outside of the airframe.
However you make a good point that the resistance of foam to Petro is an issue.
There are two ways to solve this problem from my point of view. 1) Design a structure which doesn't need the foam core to meet its structural requirements and 2) to use foam that is resistant to fuel and solvent leaks)
I probably will go with option 2. However I will do an analysis without the foam to see what the original Q-200 structure does without it. I suspect that if it was designed right the foam's structural contribution to the strength of the the fuselage is minimal... the wings are a different story. One important thing to keep in mind is that a composite structure can be built that needs no foam core. Once the proper thickness of composite is used it SHOULD be able to handle ALL the flight loads with minimal need to transmit them via the foam. I will have to determine if this is the case or not.
As to the airfoils... the main problem I ran into is the deviation from the published airfoil data while tracing the patterns. There are some mathematical differences in how the data is represented between the two versions of the airfoils in the airfoil data base.
The secondary problem has been in correctly splitting the airfoil at the control area and attaching the proper control geometry mount points to the airfoil segment. I am still in the process of looking over this... so the exterior model of my CAD file is not complete at this point. However soon will be.
Do you have any recommendations for foam? I know there are fuel resistant foams out there. Unfortunately whatever foam I will use I will have to do quite a few structural failure tests on to find out what the transmitted loads will be.
As of now I have not found any database that categorizes foam core composites with glass in compression, shear and tension. Of course this is data I will have to collect and use for the model I am working on in order to being the process of verifying the structures.
Nate