Splinter 720

[Joshua Harel]

Is any one familiar with the unpublished plans for a design called "Splinter 720" by "Wild" Bill Netzeband? It was supposed to be a 72" model with a 7 aspect ratio.
Joshua

[phil c]

I don't recall seeing plans for a 720 sqin. version.  The Splinter was a pretty simple structure.  It would be easy enough to scale up.  Span would be 72 in.  Chord about 10-1/8 in.(to allow for the curved tips).  Wild Bill liked 15% airfoils.  For something this big I'd go with 18%.- 1.8 in. thick.  Due to the long span a 2 in. thickness would help.  Spars 3/8 sq. tapering to 1/8 in. at the tip.  Rib spacing 4 in.(9 3/32 in. ribs per panel plus the 3/16 in. root ribs.)  Two forward half ribs betwen the main to ribs to keep the leading ege shape.  1/1 6in. x 2 in. trailing edge sheets. The wing would have to be covered with silk, possibly with .2oz. carbon veil over it for stiffness.

The stabilizer would be about 2 x 24 x 1/4 in.  Probably 4 booms 4 in. apart.  The booms probably 4 in. long.  Use slightly longer motor mounts, or adjustable metal mounts for final balance.  The leadouts would go about 1.75 in. behind the CG, figuring 25 oz.  and 90 mph.

I strongly suspect I'd end up with a true egg crate wing using ribs spaced about 2 in. apart and45 deg. to the spars to get it stiff enough.  The really high AR wings are prone to flexing and warping and are very sensitive to minor warps.

Have fun.

[Joshua Harel]

Thanks for your advice Phil. What engine would you recommend?
Joshua

[Steve Helmick]

I once flew Bruce Tunberg's Splinter with a G.20 .15, and found it was a wonderful flying airplane. I had a very good flying .35 original ("Masher"), and they were about equal. I also flew Bruce's 1/2a Splinter, and it was too fast for me on the short lines...but it also flew very well. It was all I could do to keep from crashing it, and I wasn't about to fly it level! Was there a .35 size back then, say 350 sq. inches?

The 720 would need a hot .45 or there abouts, I'd think. Maybe a .60, but of course, it depends on whether you want a go-fast combat-type performance or something more stuntable. Since it's a Splinter, I'd expect Bill intended it to be a hotrod. I don't recall the name of his last design, but it was 180 deg. opposite in concept, pretty much, with the very low A/R.  Steve