For that, my friend, you need to start reading the tutorials. They are littered everywhere in the FS community. Goto FreeFlightDesign.com and look at either the tutorial section or the forums. Very helpful.

http://www.fsalpha.com/home.shtml

These are flash video tutorials. The top half of the page consists of payware tutorials. If you have money in the bank, go ahead and buy one. That's if you're interested in buying one.

For freeware tutorials, scroll halfway down until you see a flash tutorial about the Helix.

www.onnovanbraam.com

This site provides text tutorials [along with screenshots] on how to understand and use splines, how to make a wheel, and how to make odd-shaped tubes, and how to set up a 3-view image for development.

The site also provides a motherload of 3-view images on human figures, ships, tanks, planes, jets, cars, even weapons, motorcycles.

http://www.suurland.com/

This site also provides 3-views as well. But don't use the tutorials, because those tuts are based on a 3D-modeling application that is incompatible with Flight Simulator aircraft development.

http://www.comet-cartoons.com/toons/

This site provides tutorials on how to make human figures as well as scripts that are very useful for Gmax. The scripts and tutorials are all based on 3D Studio Max, but Gmax is the same as that one so it's no problem.

Maybe this will help

Download it and chuck it in a folder somewhere for easy reference

Regards,
Stratobat