lml@lancaironline.net Mailing List Archive

<<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> >> First Union Securities, Inc. Listers - While doing some final checks this past weekend, I noticed the nose gear didn't want to free-fall. This was depressing, because it has always dropped very nicely in the past. So I crawled under the plane for a look. Here are my observations: 1. The air strut. I thought - maybe the air strut is too old (8.5 years) and needs to be replaced. I tried to disconnect it. No such luck. This is a two- person job, requiring removal of the bracket first. I needed someone to turn the bolts on the firewall because my arms aren't long enough to hold both wrenches. Since I was alone, I couldn't change that part. 2. The hydraulic strut - I noticed during this process (actually, while trying to reconnect the air strut) that the hydraulic ram extends about 3/16" beyond where the gear overcenter stops the strut. This means the hydraulic cylinder is pushing on the overcenter link - very hard. I went through the archives and read some stories about delaminated nose gear tunnels and adjustment of this cylinder. SO - do I need to make it so it is just barely pressing on the overcenter link when extended? Specifically - should I extend the gear with the pump, then while under pressure, set the rod-end length to the extended overcenter length? Or should I have it extend a little beyond that (i.e. open the dump valve and compress the cylinder some distance, then connect?) Part of the problem with this is that the cylinder appears to be too long. It will require that I grind off some of the threaded end of the bearing. As it is currently configured, the rod-end bearing, check nut and aluminum "stop" are all sandwiched together. Something would need to go - the check nut should stay, and there is no additional material that could be filed off the aluminum "stop". So that leaves the rod-end bearing. 3. When I reassembled all the parts, I noticed part of the "free-fall" problem - friction. The air strut rod end does not have a bearing. When I snugged up the bolt holding it to the gear arm, it didn't want to freely rotate. So I loosened the nut one notch on the castle - seemed to help. Ditto for the bolt at the "hinge" point of the overcenter link. When clamped tightly - it wants to bind too. So I have it loose enough to move freely, but no slop. I hope this is okay. Once these things were adjusted, the gear dropped nicely. Matt >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 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. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>