#### StarJar

##### Well-Known Member

Some of you had questions or made suggestions which màde me think about how to explain exactly what I have here. This may be painfully boring with obscure details, but it all ties together to explàin exactly why it is the way it is now.

The formers have notches and the formers are cut out out of chipboard on à Sizzix Eclips machine from a pàttern made on DevFus, which is à newer version of Profili.

The notch pattern is actually for straight stringers, but I just ran the diagonal stringers through the notches diagonally.

This means there are intersections AT each bulkhead, and BETWEEN each bulhead. There are 27 notches on each bulkhead. If there were less than 27 notches the lattices would hàve steeper angles, and if there were more than 27 notches they would have shallower angles.

The notches are each deep enough for 3 stringers (lattices); two diagonal sets crossing each other, and one horizontal' or lateral set which are the outermost stringers, and last to apply. This allows for structural compression and tension, gives a more streamlined outer shape, and allows for fabric attatchment.

The fuselage is quite stiff tortionally after only 6 diagonal lattiçes are inßtalled, so by the time you have all 54 diagonal lattiçes installed it is incredibaly stiff. The adition 27 'streamlined' stringers add more strength.

On the full size plane, stringers will be cut from 1/4 inçh thick unidirectional plywood sheats special ordered from Home Depot.

There are 83 stringers total, with an everage length of about 10 feet. The stringers do not run on the first 15 inches of the airdraft because the firewall is 15 inches from the nose. they also dont run the rear 15" of the aircraft, because the tailpost and tailwheel spring are 15" from the rear of the 12 ft. long airplane. A spevial lightweight, less structural tailcone will be used there.

87 striners times 10 ft. is 870 feet. the crossection of stringers is .25x.25 or .0625 sq. inches. So the volume of wood for the stringers is 870x12x.0625 or 652.5 cu. inches.

To calculate the weght, a cubic foot (1728 cu. in.) of the wood weighs 30 lbs. ....652.5÷1728 is .377. .377x30= 11.3 lbs.

The bulheads- I haven't fugured the exact weight yet, but their total area with 1/4" plywood comes out to about 9 lbs.

So you have about a 21 lb shell including hot melt glue from a gun.

Below are two pictures side to side for a larger veiw.

This is a 1/4 scale of a planned ultralight flying wing.

That is the El Centro News, thanks for watching, lol.