Introduction My Builder's Log My Flight Log Tips List of Builders Gallery Ideas for Paint Links News





I finally got my nosegear mounted and swinging freely, but not without some issues. As my friend Leighton keeps telling me, I've got to stop following the manual to the letter. It keeps getting me in trouble. Here's what happened.

I assembled the over center link and over center link arms onto the engine mount, attached the nose gear oleo to the over center link arms, installed the bearing blocks on the nose gear, clamped the bearing blocks into their approximate position on the attach plates of the engine mount, and then leveled the plane. So far so good. At this point the manual says you should adjust the position of the bearing blocks so that the nose gear is raked forward between 1 and 5 degrees. (It also says to swing the gear and make sure it doesn't bind. Very good advice. Do it every time you adjust anything!) With the bearing blocks pretty much aligned with the edges of the mounting plates (top, bottom, front, and back) I didn't have any forward rake. I loosened the clamps and moved the bearing blocks back until I had some forward rake. Oh yeah, you also have to make sure that, while you're moving things around you also keep the nose gear perfectly vertical when viewed from head on (or from the tail). I achieved some forward rake, 1 degree as I recall, swung the gear and checked for clearance. It was close, but looked ok. Since 1 degree was the minimum forward rake specified in the manual I decided to go for another 1/2 degree. This placed the bearing blocks a surprising distance back from the front edge of the mounting plates (see NosegearOld3.jpg). Apparently I forgot to swing the gear one last time because after I drilled the blocks and bolted everything in place the gear bound up when I tried to manually retract it. The 180 degree bend in the over center link tube hit the oleo housing (see NosegearOld5.jpg). Crap!

I called Lancair and got Tim Ong, who was very helpful. He had me take some measurements and send him pictures of the installation. After he talked it over with Carsten, and they checked out the clearance on Carsten's plane (I have a Lycoming engine mount, same as Carsten), Tim called me back and said they felt the bearing blocks were too far back on the mounting plates. Moving them forward would reduce the rake, but they were both comfortable with going down to 0 degrees of rake if needed. They sent me new bearing blocks and I did the whole thing over. This time I kept the bearing blocks near the front of the mounting plates. (See NosegearNew1.jpg. Note that the new bearing blocks are shaped differently than the original pair and so do not match the shape of the mounting plate as closely as before.) I now have about 1/2 degree of forward rake and a comfortable clearance at the point where it was binding on the first attempt (see NosegearNew4.jpg). All's well that ends well, I suppose.

I also have a suggestion for an additional step when installing the engine mount. Before drilling the 1/4" holes for bolting down the nose gear brace mounts (page 13-10) I recommend installing the over center link on the engine mount's nose gear brace. I had some difficulty getting the second bolt in place as the holes are tight tolerance and they ended up not being perfectly aligned. Installing the over center link first would hold the nose gear brace mounts in alignment while you're drilling holes through the firewall.

As additional information I had some quibbles about the AN hardware called out in the manual. In the for-what-it's-worth category here's the mail I sent to Carsten with my findings:

Page 13-10, Fig 13:C:1, Nose Gear Brace Mounts The manual calls out AN4-10A bolts. These weren't quite long enough and I had to use AN4-11A in order to have some of the bolt end protrude past the elastic locknut. By the way, I did use the optional spacers at the main mounting holes and then did a release at the nose gear brace. The -10A probably would have been long enough if the spacers weren't used.

Page 13-12, Fig 13:D:1 (5 items) 1) The AN4-11A and AN4-12A bolts (I do have the optional Tow Bar Plate) used to attach the nose gear fork weren't quite long enough. I used -12A and -13A. 2) I found that AN3-7A were plenty long enough to attach the right side bearing block to the engine mount, and that was using an AN960-10 washer between the bearing block and the engine mount plate at each bolt. (The manual calls for -10A or -12A.) If someone is able to use thinner, or no, spacers a -6A would work. 3) AN363-428A locknuts are called out for attaching the over center link arms to the over center link weldment. The hardware kit has AN363-428 metal locknuts, but no AN363-428A nuts. 4) AN5-17 bolts are called out for attaching the over center link weldment to the nose gear brace portion of the engine mount. A later page in the manual (I don't have it in front of me right now but it's the one that shows the retract yoke) calls out AN5-20. Neither bolt is in the hardware kit but there are some AN5-17A bolts. 5) A retract yoke bushing, 4739, is called out that I can't find in any of the parts I have.

Hope you and other builders will find this useful. Of course not every builder tries to follow the darn manual as slavishly as I do. Most probably have the sense to modify slightly if it looks like it will work better. I keep forgetting that they probably wrote most of the manual based on putting one airplane together, and of course not all planes are going to be exactly alike. Someday I'll learn.

If you have further questions don't hesitate to ask me,
Tom Gourley













Home | Introduction | My Builder's Log | My Flight Log | Tips | Legacy Builders | Legacy Gallery | Ideas For Paint | Links | Legacy News

Copyright © 2005. All rights reserved. This site is the builder's log of Don Barnes and for the purpose of sharing information and opinions related to building a Lancair Legacy. Any person using these images, ideas and tips does so at their own discretion and risk. No responsibility is expressed or implied and is without recourse against anyone related to this site. This site is not affiliated with Lancair International or Neico Aviation Inc., however, we love their aircraft.

Design by Cellar Ideas and produced with GoLive CS. Hosting generously provided by Rob Logan