lml@lancaironline.net Mailing List Archive

<<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> Peter - I understand that some of the LNC2 kits had nose gear phenolic blocks mislocated slightly. It may have been the upper phenolic block (static end of the nose gear cylinder), which would result in the situation you describe. Or it was the phenolic blocks on the side of the nose gear tunnel (pivot rod attach point). Perhaps the other guys can comment on this, but it doesn't really matter. The end result is that you've got a problem that needs fixing. You've got a properly located pivot rod and your nose gear locks in place with a 4 degree forward slant. This is good, and you want to keep it that way. There are three options to making your situation happy, one of which is easy and the other two are hard. But there is a hidden problem of which you should be aware -- more on that later. 1) You could get a cylinder with a shorter rod (if you can), or rework the present rod (cut it shorter and extend the threads) and use the existing phenolic block and brackets. I think a competent machinist could do this in less than an hour. So that's a $50 fix, but you'll need to have this done again if you ever have to change the cylinder. 2) You could rework the phenolic block by cutting it out and putting in a longer one. That's a REAL pain and I'd recommend against it. 3) You can make a pair of new brackets which have the hole located slightly aft of the present ones. This is the easiest solution. The hidden problem is when the hydraulic cylinder is fully extended with the gear down. If the rod is a little too long (or is adjusted that way) then there will be substantial force applied by the static end of the cylinder onto the phenolic block, and the block will pop out by tearing itself out of the fiberglass which contains it. It doesn't happen right away but it does happen eventually. This has happened to several people already. This will happen even if your phenolic blocks are in the right place and the cylinder is merely adjusted to be too long, so it's a problem for all of us. Fortunately this situation is easy to avoid. You extend the cylinder all the way, and make sure the cylinder is pressurized with hydraulic fluid for the final adjustment. The cylinders are noticeably longer when pressurized than when extended by hand (not enough to see, but it is important to account for). You then adjust the rod end so that the attach bolt to the overcenter link will just drop into place. This is what I'm concerned about with your siutuation. If you reverse the brackets as you suggest (not a problem) and screw the check nut all the way down (not a problem) and it just fits perfect (not a problem), but then you pressurize the system and the rod extend just a tiny bit more (which it does), then you no longer have the adjustment capability to remove the preload on the upper phenolic block and it will fail eventually. - Rob Wolf LML website: http://www.olsusa.com/Users/Mkaye/maillist.html LML Builders' Bookstore: http://www.buildersbooks.com/lancair Please send your photos and drawings to marvkaye@olsusa.com.