You probably know about flying and landing wires on bipes and ancient monos. Most scale builders include these for looks only. I recommend they be made totally functional on any Quarter-size or larger model.
The Jury Strut serves nearly the same purpose as the landing wires in that it insures the integrity of the wing during negative "G" situations. The wing strut alone is fine for positive "G" loads if properly set up; but without a functional Jury Strut that same wing strut is prone to bowing and snapping when air pressure (or a small child) pushes down on your wing.
A 20 to 30 inch 1/2" x 1/4" spruce (or other equally feeble) strut is just fine for those who fly straight and level with a totally vibration-free engine... and every landing. However, some of us do fly in a somewhat different manner and must concern ourselves with struts that work under both tension and compression.
Not less than one of the popular jumbo kit manufacturer leaves this lifesaving device completely off, or merely includes it for scale appearance only. Current production kits may have improved in this area, but the Howard DGA-6 (Mister Mulligan) I built two years ago showed "fake" Jury Struts on the plans; the upper ends were to be run up through small plywood plates in the underside of the wing.
The Citabria kit I just finished didn't show a thing.
I've seen a beautiful J-3 Cub assembled and flown with the "fake" Jury
Struts missing those little holes, which caused an unsightly and dangerous
half-inch bow in the struts.
As in skinning cats and mounting canopies, there
are probably a thousand and one ways to set up struts
and Jury Struts. Here's how I've done it on two
different airplanes.
