Nose Gear Plates


The Nose Gear Plates, or NG-2 Bulkheads, are pretty much like the other bulkheads with a few additions.  In fact, I'm not entirely sure why I've devoted a whole section to these parts, but that's the way I set up the Construction page, so I guess I'll roll with it.

Construction began the same way: cut out the high-density .25" thick foam core and sand it to match the template I fabricated a few weeks earlier.  Actually, in this case I built 2 cores, because both left and right parts are required, and they need to be perfect mirrors of each other.   "Why?" you may be asking.  As the name implies, the Nose Gear Plates serve as the attach points for the nose landing gear and its retraction devices.  If the parts are not alike, the gear installation will be skewed which could lead to binding during retraction (or worse--during extension).

The inboard surface of each part was glassed with 2 plies of EBX-1800 cloth, cured, trimmed, and sanded to match the template.  On each part, there are 4 areas (bolt/attach points) that need to be strengthened by boring out the core and building up the area with glass plies instead.  This operation is a bit tricky because the hole saw needs to be positively controlled: cut too shallow and you don't get all the core out.  Go too deep, and the hole saw cuts into the inboard plies that I had just layed up.  Using a drill press, and setting the cut depth using some scrap pieces of core helped a lot.  Then came the tedious job of cutting a bunch of circular pieces of glass.  Thousands of them.  Maybe tens of thousands.  Well, maybe I'm exaggerating a bit.  But I'm sure it was at least 100.  The circular pieces were then bonded into the holes, and the outboard sides of the parts were glassed.

But wait, there's more.  On the outboard side of each part, 4 aluminum crush plates are bonded, faired around the edges with an epoxy/flox slurry, and glassed with some Bi-Direction (BID) cloth.  On the first crush plate, I made the mistake of sloppily applying the flox and allowing it to cure before adding the overlay BID ply, thinking it would just take a few minutes to sand it down to a smooth radius.   Wrong.  As I mentioned before, cured flox is some tough stuff.  I'd say it took about an hour to grind/file/sand that stuff down to a nice radius.  Needless to say, I didn't repeat that mistake when installing the other 7 crush plates.

But wait, there's still more.  On the inboard side, yet another aluminum crush plate (NG-8 for those of you taking serious notes) gets installed at the nose gear pivot point.  Unlike the other crush plates, this one is mechanically fastened rather than bonded.  The NG-8 plates that were supplied with the kit were in pretty bad shape: scratched, holes out-of-round, lousy countersinks, and generally not the type of parts I wanted on my airplane (show me).  I faxed a drawing of the parts to my Dad, and he built me 2 new ones at his workshop which looked--and worked--great.  When you're done cruising my website, check out his at http://www.proto-teck.com.

Once all the parts were installed, the last step was to mate up the 2 bulkheads, and open full size holes through both parts simultaneously.  The drill press strikes again.  That's about it.


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