Gear Leg Fairings
Even as I have not yet completed review of the plans, I have decided to change the plumbing of the brakes. The Chad Robinson build used permanent installation of a nylon tube (.25" od, .125" id), running down the main gear legs and enclosed in a fairing. The preferred standard is hard lines where there is no movement and, where there is movement, braided stainless with a PTFE core. Unfortunately, that change means cutting out the existing tube. If I'm to do that, I might was well change over to the preferred fairing from Eureka CNC. Here are the shapes, ready for use.
Ouch - these precut fairings won't fit over the existing fairing work. I'm back to the starting point, less not-insignificant cash. After a 3rd pass closely examining the gear legs, then looking through the drawings, plans, Lucubration log and the Cozy builders discussions, I am confident that the gear leg torsional wraps were all done, then layup of this fairing. Therefore, I can cut the existing fairing without reducing the strength of the gear legs. Confirming that is a comment from the guru:
Aha - if you've already got the fairings well outside of the torsional layups, then you can definitely cut a channel in the TE of the fairing (totally non-structural) and lay in your new brake lines, then cover the channel with 2 BID and re-fair in the surface. Marc J. Zeitlin 3/14/17
I marked and made the cuts, leaving the existing tube on the right leg, and then cleaned out the trailing edge.
I looked for a flexible tube in which to run the planned stainless PTFE brake lines. The plans call for using a vinyl straw. To get something light with the diameter big enough to handle future service needs I fabricated tubes from BID, pieced them to fit the gear leg cut offs, then micro'd them in place on the cut offs. My test amounted to dropping a -3 fitting through the tubes - it came out just fine! Next comes the re-build of the fairing, where I aim to achieve a decent airfoil.
I'm aiming for an airfoil shape that scales well (the gear leg has varying thickness) and symmetrical should be easier to build. I went with NACA-0021:
Saturday 8/25/18 6.0 6.00 sand lower right strake
Monday 8/27/18 4.0 gl micro fill on strake lower + right gear leg, green stage sanding
Wednesday 8/29/18 1.3 gl document brake set up, refer for advice, research running brake lines
Thursday 8/30/18 29.31 gl sanding supplies - HFT
Friday 8/31/18 0.3 gl sanding strake lower + right gear leg, shaping fillets
Saturday 9/1/18 1.0 gl sanding strake lower + right gear leg, shaping fillets
Sunday 9/2/18 4.0 gl sanding strake lower + right gear leg, shaping fillets
Monday 9/3/18 3.0 gl sanding strake lower + right gear leg, shaping fillets
Tuesday 9/4/18 3.0 gl sanding strake lower + right gear leg, shaping fillets
Sunday 9/30/18 2.0 gl marking gear legs for cuts
Monday 10/1/18 1.0 gl cut TE from right gear leg, prep for next steps
Wednesday 10/3/18 1.0 330.29 gl cut TE from left gear leg, parts for next steps
Friday 10/5/18 1.0 gl inventory ACS order, shape gear legs for next steps
Saturday 10/6/18 2.0 39.85 gl prepare gear leg for brake line; purchase of tubing
Sunday 10/7/18 1.0 gl inventory ACS order, shape gear legs for next steps
Monday 10/8/18 1.0 gl inventory ACS order, shape gear legs for next steps
Tuesday 10/9/18 1.0 gl slice open gear legs, fashion a right sized tube
Wednesday 10/10/18 1.0 gl prep the space for reattaching a trailing edge
Thursday 10/11/18 1.0 gl research gear leg shapes
Friday 10/12/18 1.0 gl build airfoil templates
Saturday 10/13/18 1.0 gl re-build airfoil templates
Sunday 10/14/18 1.0 gl measure legs against templates, reattach trailing edge, wrap one leg
Monday 10/15/18 1.0 1,672.43 gl ordering brake parts
Thursday 10/25/18 10.0 145.30 gl multiple small sessions of building up leg fairing, buying fabric
Friday 10/26/18 3.0 33.27 gl ordering parts - micarts for nutplate support
Saturday 10/27/18 3.0 20.98 gl shaping GL, buying drill bits, #30 and #40, for nut plate rivet work
Sunday 10/28/18 1.0 gl trying to fingure out an accurate method for incidence of GL fairing
Tuesday 10/30/18 1.0 71.12 gl setting p incidence, ordering nutplates + supplies
Wednesday 10/31/18 1.0 gl filling & sanding on GL's
Thursday 11/1/18 1.0 gl filling & sanding on GL's
Sunday 11/4/18 1.0 gl filling & sanding on GL's
Monday 11/5/18 1.0 gl filling & sanding on GL's
Tuesday 11/6/18 1.0 gl filling & sanding on GL's
Wednesday 11/7/18 1.0 gl filling & sanding on GL's
Thursday 11/8/18 1.0 gl filling & sanding on GL's
Friday 11/9/18 1.0 gl filling & sanding on GL's
Friday 11/30/18 1.0 gl filling & sanding on GL's
Saturday 12/1/18 1.0 gl filling & sanding on GL's
Thursday 12/20/18 1.0 gl gear leg cover - fitting & nutplates
Friday 12/21/18 1.0 gl gear leg cover - fitting & nutplates
Saturday 12/22/18 3.0 gl gear leg cover - fitting & nutplates
Sunday 12/23/18 2.0 gl gear leg cover - fitting & nutplates
Monday 12/24/18 1.0 58.20 gl gear leg cover - fitting & nutplates + order battery