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View Full Version : Yippee! Wingbar

Bro
Apr 28, 2003, 02:03 AM
On a 98-108" Plane with 800-900 sq. in, 85-115oz. what would be the safe diam. for a wingrod on a two pc. wing. 10mm-12mm?
And, what size with steel vs. carbon rod.
I am hoping to go 150-180mph :D
Ollie
Apr 28, 2003, 06:55 AM
The maximum bending moment at the center of the wing depends on the mass of the plane that is not distributed as the lift is distributed spanwise. A rough assumption is that about half the mass of the plane is a central, inertial load. The maximum bending moment also depends on the maximum lift coefficient of the wing and its airfoil. The maximum G force depends on the diameter of the tightest turn.

A more conservative approach is to design the joiner for the maximum lift that the wing can generate at 180 MPH. The airspeed of 180 MPH and airfoil chord put the wing in an operating range where wind tunnel data is scarce and rough estimates of the maximum lift coefficient are required.

The upshot of all this is that you should use the biggest joiner that will fit in the thickness of the airfoil and if it is less than about 3/4 of an inch in diameter, you should use two joiners as large as will fit in the thickness of the root airfoil. The expense of over designed joiners is small compared to the expense of a failed joiner system.

Rectangular crossection joiners are more eficient structurally than round joiners. A one piece wing is more structurally efficient yet.
Bart Vaio
Apr 28, 2003, 09:26 PM
98" to 108" is a pretty wide range, (be forwarned I am no engineer) From experience we all know wizard compact joiners to be good to 186 mph+/- without failing, this joiner may be a good choice for the 98-100" range. Also the Nyx F3F, which is 112" in span has proven itself to 184 mph it's joiner is ridiculosly large at 1.6"w x 15.0"L both of these could be purchased from their respective importers I assume. Wiz joiners from et-air.com and Nyx joiners from f3x.com. But these are just some of the options I am sure CST has some solid carbon rod in the 5/8"+ range that could fit the bill but they probably will not have the dihedral you want...