Smoking Ace Pt.1

Ok, this is not the most verbose of howto's .I will start explaining the most important parts of the pics belo.w.
These are the basic structural elements of the Smoking Ace fuselage.

One thing that I have to say is that it is going together quickly. There are some unforeseen technical bits trying to assemble the fuselage. Mainly around the stiffness of the joints between the sections. The fuselage is 42" long at the moment. A tail and nose cone have not been added, I hope to have them and the lid done soon.

Special thanks to Bill Sheffer at Unique Cutting & Metalworks for his help and support on this project!

The Smoking Ace is in the jig

I got the parts for the Smoking Ace this weekend from Bill at "Unique Cutting and Metal Works". Bill is great to work with and help us on this project.

The parts are coming together well. They were bracketed this weekend and got a coat of enamel. The issue that I see at the moment, is that small variations in a straight line make a big difference now that the spars are weight reduced. Lots more small radii to worry about. I do not think it is a big deal, but I lost a bunch of holes because they were too close to other penetrations.

The best thing, that has come out so far, is that the battery carriers really look like they fit as designed. That is cool, I hope that I can get the heat pipe design to work too. One of my coups of engineering will be to steer some of the motor, esc and battery heat to the same spot across a Peltier device and out to the free stream. I am not sure it will be worth more than a few volts, but something is better than nothing. Peltier recovery is one of several technologies that we hope will get our electronics power-management efficiency up.

I will get some pictures up as soon as the fuselage gets a bit further along. One of the most interesting things about this design, is that it is based on triangles. Any third year structures student will remind you that triangles are the only self supporting shape. Self-supporting makes the air-frame easier to construct because it tends to stiffen up as you assemble it. This means that you can break the assembly up a bit more than normal and things self-support and then support when assembled. Anything that makes this easier to do is good.

More to come.

Building on a Budget

So we are working out our system to build giant-scale planes on a budget. We build mostly our own designs. It is far more challenging to wing it. I have to say that building from forms is pretty challenging, and worth it for those of you who like to do it their way.

One suggestion that I have for you guys is, lattice. Maybe that is not an obvious description. We have the most luck building complicated curvatures, when we lay out a regularly spaced net of 1/16th inch (1.5mm) balsa strips x 1/4" (6mm) . The spacing is what ever makes sense for the model. I mean, you will need to work out some of this for yourself. We find that wings are good with 6"(15cm) pieces cord-wise and 20- 25% spacings span-wise. That way there is a reasonable pitch and still a good amount of coverage. Onto this, you glue your actual skin down.  This helps reduce the actual curvatures involved, but also allows for the skin to be supported without the need of a foam internal block. Use wood glue if you are working on a Styrofoam base or CA if you are working on a compatible base. CA will eat Styrofoam, even the vapors will destroy it.

We get all of our balsa from local suppliers. Our favorite supplier is www.solarbo.com .