Fixed Gear Fairing Modification

From Velocity Aircraft Wiki
Jump to: navigation, search

This modification comes to us from Jorge Bujanda.

Main Gear-Fuselage Fairing Modification

Jorge Bujanda

I did not like the way the plans approach the installation of the main gear-fuselage fairings on a fixed gear. The fairing is supposed to be bonded to the leg and a significant gap left between the fairing and the fuselage. This is to allow leg movement from the gear’s fully loaded position at gross weight to the unloaded position in flight. Instead of bonding the fairing just to the gear and leaving the gap between the fairing and the fuselage, I modified the setup by bonding the factory-provided fairing both to the leg and the fuselage and made the gap on the fairing itself. Although I made significant modifications to it, the original idea about locating the gap on the fairing was not mine. I saw a similar set up on a canard aircraft several years ago, while surfing the net, and decided that was what I would do. Since then, I have not seen a similar set up in other canard aircraft and therefore believe the idea is not that prevalent in the canard building community and have decided to share it. This approach makes total sense, at least to me. It results in a much cleaner and aesthetic finish. I tested the displacement of the attached parts over each other by unloading the gear. I had to increase the gap a bit after I started flying but the setup works as expected and has shown no signs of damage to the fairings after 80 hours and many landings both very light and very close to gross weight.

1. I filled and finished the provided fairings to fit the fuselage and leg as much as possible.

MG Fairing 04.jpg
MG Fairing 05.jpg

2. I made a cut on the inboard side of the fairings to allow removal and replacement of the fairing after some weight was placed on the airplane. I wanted the fairing to look as aligned as possible with the airplane sitting on the ground. Therefore, I installed them after the airplane was ready to fly and the fuel tanks were half full. I have not painted or upholstered my airplane yet but feel that some minor filling will take care of any misalignment in case it varies significantly after their weight is added to the airplane.

MG Fairing 03a.JPG

3. I marked a straight cut line parallel to the fuselage surface around the part with a laser light.

4. I cut most of the part with a cutoff air tool and/or a hacksaw blade, leaving uncut portions to keep both parts aligned during the bonding process.

5. I bonded the partially-cut fairing to both the fuselage and the leg with flox, cleaned the excess and allowed it to cure.

MG Fairing 01.JPG

6. I finished cutting both parts of the fairing with a hacksaw blade after curing. Be careful not to damage the gear leg or the brake lines. I have my flexible brake lines inside a larger polyethylene tubing that allows protection and easy replacement.

7. I sanded the fairing gap with a coarse (36) sanding disc to about 1/8”. I believe the gap is large enough for both parts to slide over each other without touching.

8. I filled with microballoons and sanded to shape, finishing it with primer.

MG Fairing 06a.jpg
MG Fairing 07.JPG

9. I tested them unloaded by jacking the airplane up while adjusting my wheels and the gap seemed wide enough. I noticed that the areas most prone to touch are the fore and aft points. Should there be a need to increase the gap for clearance while landing, only some sanding will do.