Tubing

Last month we described an experiment to determine ways to maximize the strength of a weld involving 4130 chromoly tubing.

You’re one of the participants in a somewhat dull hangar flying session,and suddenly the urge strikes you to liven things up. A great way to do this would be to say, "I’ve finished welding my homebuilt’s fuselage and am wondering whether or not to normalize it?"

Last month I began a discussion concerning building a tube and fabric airplane. The first three steps of the building process were discussed in that article. As a review, the steps are (1) decision and planning, (2) basic building phase, (3) preliminary assembly, rigging, and systems installation.

Building an airplane is a challenging task. The decision should be made only after you have determined what is required financially, emotionally, and physically.

All right, everyone out there who thinks welding was invented by Merlin the Magician and is an exotic combination of alchemy and sorcery, hold up your hands.

I am a Technical Counselor, an EAA member and a member of EAA Chapter 176. When building my Tailwind, I fabricated several fixtures that should be useful to others using steel tubing construction.

Before getting into the nitty-gritty of actually welding the fuselage together, let's review the assembly chronology of putting the fuselage together in the first place.

Knowing how to weld tubing is one thing; but knowing how to get it ready to weld - the cutting, the fitting, the jigging, etc., is another entirely different skill which must go hand in hand with that of welding.

One of the fortunate things about aircraft welding is that it has been around for so long that there is a tremendous backlog of experience which covers just about every type of problem or mistake that can be made.

Although the majority of the steel fuselage and tail is made of tubing, most of those areas where stress is transferred by fittings is composed of a series of flat sheets or plates bent and welded to accept bolts and transfer loads into the tubing.