Friday, December 22, 2006

Fairing the gear legs

I've been flying around with the new wheel fairings for a few months now and actually have myself 90% convinced that they aren't going to fall off or in some way run afoul of the rotating bits down there, so I finally started changing out the old aluminum leg fairings for new fiberglass fairings. This also entails replacing the old upper intersection fairings with new, and adding lower leg fairings where none had existed previously.

As I've said before, what with this being essentially a hand made airplane there is no such thing as "off-the-shelf" parts. That said, pre-made fiberglass parts are available (at a fairly dear price!) that theoretically enable novices such as myself to at least get two-thirds done with a project (by starting us out half way) before throwing in the towel. They do the hard part of creating the molds and laying up the glass, and leave the easy stuff like fitting and installation to us. It's a pretty fair deal all in all, and I relish in the regulatory freedom that allows me to do it. And hey, it's fiberglass, and you all know what I say about working with glass: the great thing about it is you can trim a lot of material away quickly and easily. The horrible thing about it is, of course, that you can trim a lot of material away very quickly.

The first step is pretty obvious: remove the old stuff. Here's the naked leg exposed (and yes, I do expect an uptick of Google hits from using that phrase):

Probably more for reasons of ease in production than any kind of necessity, the gear fairing as it comes out of the box is far larger than what the final trimmed length will be. I made an eyeball measured rough cut on the left fairing and fitted it to the gear leg. The unmolested right side fairing is propped up for comparison:

The upper fairings come as a closed piece, but there's no way to install it that way. The old fairing was cut open in the back to allow it to slide over the gear fairing, so I went with that strategy. It was easy to get a nice, straight cut with a hacksaw:

Once the cut was made, I could slip the upper fairing into place and get an idea of how much more the leg fairing would need to be trimmed to get it to a length that allowed the upper fairing to fully enclose the leg fairing. You can see that there's still a good half inch of the leg fairing sticking out the back of the upper fairing in the picture below. It ultimately required another 3" to be trimmed off the top of the leg fairing to achieve the best fit. I, as is my wont, removed 3.5".

As I shortened the fairing, I had to keep reminding myself to trim from the top rather than the bottom so I could slide the fairing higher up the leg, thereby reducing the width that the upper fairing needed to cover.

Here's all the pieces/parts thrown into the general vicinities of where they will ultimately end up:

I haven't trimmed away any of the excess material around the lower fairing, but I can already see that I'm going to have a fit problem between the Team Rocket lower fairing and the Van's wheel fairing. I'm stumped as to how to better fir the lower fairing. I have a heat gun, so I could try heating the piece to see if I can get it to re-shape, or I could build it up with more fiberglass. The jury is out.

This is what it will look like when done (well, in general. I don't intend to use the making tape, for example, and there will be a lot of trimming on the upper fairing. Oh, and there will be paint, too.):

I posted a question in the Vans Airforce forum regarding what to do with the lower fairing, and in the meantime I'm going to go ahead and get the leg fairing properly mounted. That will require a little more cutting, a little bit of additional glass layout, and a fairly complicated operation intended to correctly align the leg fairing with the in-flight airflow. I'm actually kinda dreading that last part.

Later: less than an hour after I asked, I have a couple of answers. One suggests laying up some glass on the wheel fairing and the other calls for major rhinoplasty on the fairing. The wheel fairings aren't painted yet, so it would be no big deal to add more glass.

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