Goldberg "Gas Bird" Construction Project Session #4

By Tommy Gray
AMA 17063

With the "tail feathers" well on their way, I decided to take a break and start the fuselage construction.  The Gas Bird fuselage is a "diamond" shape like that of the Lanzo Bomber and a few others.  To build it, you might think it would be difficult, but in actuality, it is relatively easy.  First, I built two identical fuselage sides over the fuselage plan, building the second one on top of the first one so that they would be mirror images of each other.

When I built the sides, I had to sand a taper into the ends of the longerons so that they would blend into each other as you can see in the next picture.

Once I had the sides built, I then started "assembling" the fuselage.  It has a square cross section as I previously mentioned.

I started by cutting all the cross pieces over the plans, and making sure that I had two identical sets of pieces.  I then pinned the first set over their location on the plans in preparation for attaching them to the sides.  I do not have a fuselage jig, so I am going to have to rely on my square and a good eye to make sure that the thing is perfectly square all all the way around.  The front of the fuselage is pretty well straight until you get back to about the 5th cross piece, so here is how I put it together.

I first once again sanded in the taper at the rear of the longerons so that when the sides were joined the fuselage would look the same on all 4 sides.  I then glued the rear together.  Next, I placed the attached sides over the pinned cross pieces at the front and started gluing the sides to the bottom cross pieces one at a time, making sure that I had each location perfectly square using my square before the glue setup.  The reason I started in the front is that since it is pretty straight I could join the front of the fuselage together, add the top and bottom pieces, and then it would stay as a unit and would be easier to handle as I worked my way to the rear.

In the pictures above you can see that I have positions one through four glued in place, and have removed the pins so that I can work the fuselage down over the remaining cross pieces as I go to the rear ( the front of the fuselage will kick up off the plans as you press the rearward ones down to the plans). As I got one section glued in, I removed the pins, and pushed the sides down over  the remaining cross pieces until I have made it to the last one, and I am done.  Once again, keep in mind that I am very careful to keep things square as I go.  I have done it this way for many years and it works for me.  Next year I plan to build a jig, but until then, I have a lot of planes to work on before the '09 Champs so a jig will wait until next season.

Here we are at the end with one piece remaining!  Whew!!

Well, wondering how straight I managed to build it with nothing but a bottle of glue, some pins, and a hand square?  Look below.

First, I always thought this kind of a picture was the coolest thing, so I could not resist!  It puts me in mind of the "Twilight Zone" or something similar! Stare at it for a while and you will get dizzy! 

Just to prove to you that it really is straight, take a look down the length of the top longeron.

Close enough for you?

O.K. back to the build.  you will notice in the picture above that there are some little "stubs" sticking out past the first cross pieces.  These are so that the 1/4" plywood firewall can nestle snugly into place and use these for a guide.

Here is the plywood firewall form the kit.  Sadly, however, it was a little TOO snug and had to be not only squared up (which I did on my sander) but the corner notches had to be relieved a little so that it would go into place between the little stubs.

To glue the firewall in place I pulled out some epoxy and mixed up enough that I could get a really good bond.  This is one piece you don't want coming loose!

I put a few clamps lightly on the firewall to hold it in place while the epoxy was curing

Once the epoxy was dry, I trimmed off the remaining stubs and sanded everything flush with the front of the firewall.

I could not resist starting the stab mounting to see what things would look like partially assembled.  The Stab sits on the two side longerons.  I will build a stab mount out of some 1/8" balsa when I get time but for now, I trimmed off some of the top longeron, and slid the unit into place for a "look see".

A side view.  Notice that I will have to "flatten" the top of the side longerons when I add the mounting plate in a few days.

The view from another position.....

Still another angle.

Well it is getting late and I have to work tomorrow so that is all for now!

More to come.....Tommy!

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