Try Marine CRCLooking for suggestions on what to clean the inside of the jury struts with? I'm thinking the best way is to soak them in something, but not quite sure what to use, any suggestions?
I have never worried about them. Their only purpose is to keep the lift struts dead straight. They have very little strength beyond that. .
Really? They keep the spars straight, using the rigidity of those .032 steel lift struts?
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Good link. Mike makes a point that a wing on sawhorses without leading edges is loosey goosey. It surely is, but that rear spar is not bending. It is twisting a bit, but a jury strut does not inhibit twisting, since, among other things, it is pinned with a joint that can rotate.
Spars simply do not deflect much in the vertical direction. Try it - you can stand on a rear spar, and not see more than maybe 1/8" deflection end to end. Without ribs, it could rotate, and then bend or fail, but if loads are vertical it will not move much.
Interesting discussion. I am going flying. I have to admit - I really don't know what the J4 jury struts look like. Flies fine.
I am no engineer but I am with Mike, jury struts are just as important as any other small component to the overall strength on the wing
I agree with Gordon (I do not possess the ability to analyse this on paper) with the observation that it is likely the primary purpose is to control the oscillations or the natural resonant frequency of the entire wing assembly more than the negative G compression loads on the strut. The negative G compression load carrying capability of the struts will be doubled when the jury strut holds it stable at the center.5. On an assembled plane, absent the jury struts, just feel how floppy the lift struts are. They're crazy-floppy. They need stabilization for negative g's for sure, and possibly for oscillations.
Actually, it will be quadrupled because the critical buckling load varies inversely as the square of the unsupported length.The negative G compression load carrying capability of the struts will be doubled when the jury strut holds it stable at the center.
If jury struts only served to keep struts straight they’d be more effective if they were perpendicular to the strut, yet they’re perpendicular to the wing.