Chapter 21 - Section 2A

Feather Lite Leading Edge

 

I decided to add this section to the document for my Feather Lite leading edge assembly process. Obviously, this section is not per plan...

 

One of the most 'judged' profiles of the plane is its leading edge. After flip-flopping umpteen times, I decided to go with the Feather Lite pre-made leading edge. Besides looking good, its supposed to hold an extra 5 gallons of gas per tank. In case you are wondering if this pre-made leading edge will save you some build time...here's a short answer to that thought...HA!

 

The leading edge arrived within a week because I got the last set of a pre-made batch. The first thing I did was to match a strake rib template to the cross section of my wing root as well as the LE. Here's a paper template of R57 - looks like it matches my wing profile relatively well. So far so good.

 

 

 

 

 

 

 

Then I lined up the paper template to the Feather Lite leading edge. To my surprise, the spread on the LE is much wider than expected. I had a hard time visualizing how I can squeeze the LE to fit the template profile without cracking the foam. Then panic set in...

 

After a few phone calls to Feather Lite and previous builders using the Feather Lite LE, I was convinced that I need to make several fine cut lines on the foam such that I can 'fold' the LE to fit the ribs. Actually, I was less than thrilled about it...I cut out a few small strips and tried to figure out where to make the cut line...lots of fiddling time wasted. 

 

 

 

[Hindsight] It turned out that when the LE is mounted at an angle (49o) to the ribs, I do not have to squeeze it as much as initially thought - I only made 1 cut (approximately 1") below WL17.4 and 2 cuts at the joining edge to the top skin. 

 

Extended Strake or Not

The LE came almost a foot longer than needed. I thought it may be a good opportunity to use the extra length and turn it into a Cozy Girrrl's Strake configuration. The idea was to cut the LE into two sections - one from the wing root to R33. The second section (which is one foot+ longer) can go from R33 to where ever it meets the fuselage. Notice the extra LE length overlapping the wing section? After much...much...much...more flip-flopping, I decided to go with the plan's approach. Besides, the Feather Lite LE allows me to open up the access hole larger than the plan's version anyway. 

 

 

 

 

 

Cutting the LE to Length

Due to the angle of the LE, it was more difficult to trim it to the exact length than expected. I eventually took an R33 template and traced it out onto the fuselage at the plan's location. Then I cut out the hole with my FEIN tool.

 

The next step was to trim back the foam at one end of the LE such that I can slip it through the hole in the fuselage.  

 

 

 

 

 

 

 

Here's a picture of how the LE slips through the hole in the fuselage...This opening to the fuselage is a bit larger than plan - which is nice. Actually, I plan to open the hole even a bit more (aft) for more elbow and shoulder room later on.

 

 

 

 

 

 

 

 

 

 

 

 

 

Since the LE is plenty long (with one end slipping through the fuselage, while the other end meets the wing), the plans OD (Outboard Diagonal) bulkhead does not really apply in my case. However, I do need a bulkhead to support the outboard end of the LE. I followed Jon Dembs' approach and added a small bulkhead that has the same profile as the wing root and glassed it about 1" inboard from the tip of the center section spar. Once cured, I cut a sizable hole at the center such that I can use the empty space for extra cable lengths and equipment. In addition, I needed the access space for glassing the outboard end of the top and bottom skin to the LE.

 

 

 

 

 

 

To squeeze the LE to conform to the ribs profile (R33 and R57), I clamped two 6' aluminum angle beams (top and bottom) such that I have a straight profile.

 

 

 

 

 

 

 

 

 

I decided to put the wing back on before floxing and glassing the LE in place - just to make sure they line up ...

 

Once cured, I glassed and peel-plied the ribs to the inside of the LE. This was tougher than expected because of limited access room, especially at the acute angles at the tip of the ribs. However, I managed...

 

 

 

Now I return to Section 02...