38% Bill Hempel Decathlon
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Mar 27, 2010
, 09:52 PM
Joined Jun 2004
The wing and jury struts were pretty much installed as supplied except for the addition of brass sleeves and epoxy in the jury strut ends and the use of 6-32 all-thread in the cross members. The jury strut cross members had pre-bored hardwood dowels installed in the ends and it looked like the idea was to attach them to the “T” block and straps with the 6-32 cap screws supplied. The problem here is that the jury strut “T” blocks that attach the jury to the main struts are forced into alignment with the main struts by the straps that wrap around them. This means a straight shot through the “T” blocks into the cross member is almost impossible. I actually had to open the hole in the “T” blocks to 7/32” diameter in order to get the all-thread rod to pass through. I have seen some build threads for Hempel Cubs where the modeler has simply bolted the cross member on the outside of the jury strut assembly but that didn’t suite my taste and besides, the dowel in the end and the length of the cross member seemed to point towards the installation I chose. I replaced the supplied cross member tubing with heavy-wall T6 aluminum of similar size rather than boring out the kit pieces. This system seems to work OK.
I also had to modify the ends of the jury struts in order for them to fit in the channel blocks attached to the wing. I used the 6-32 cap screws provided for attaching the channel blocks to the wing and they don’t leave enough room for the end of the jury struts and the cross-hole for attaching them. I should have replaced the cap screws with round or pan head for attaching the channels but chose to grind the end of the struts instead. This didn’t leave much room between the end of the strut and its attachment hole so I decided to add the brass sleeve and epoxy. An advantage in doing this is the “anti-crush” action on the strut.
I use US Composite epoxy, sometimes West Systems, and cabosil and 404 high density filler where appropriate. I make a “cakefunnel” applicator as shown using freezer paper and masking tape. Be sure to put the plastic on the freezer paper to the inside. This little device allows you to precisely apply epoxy where needed or you can open the end as required and pile it on. I use this anytime I need to make a fillet or apply epoxy in tight areas.
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Using the "cake funnel" to apply thickened epoxy into jury strut ends
cross member and all-thread
6-32 all-thread, tube and locknut in position
Cross member and jury struts
First fit of the wings. Everything fits great.
Overall shot of the strut assembly ready to be fitted for a bubble wrap sleeve
Close up of the cross member showing how the rear "T" block is angled towards the strut plane by the strap
Last edited by Asher Carmichael; Mar 31, 2010 at