Wheel Pant Alignment and Cutout

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Yes, the carbon fiber backing plates I purchased came completely fabricated with 1/4 axle holes drilled and nutplates riveted in place. I spoke to the seller, and he said that the plates work with straight gear legs with wheel pants, so as I mentioned my next step is to put the gear onto the fuselage, raise the tail to simulate level flight, then make measurements to spot the holes in my pants so the horizontal rib line is parallel to the direction of flight.

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Update: I solved all of my wheel pant alignment with gear leg issues so the pant streamline longitudinal rib is parallel to the air stream in level flight. The key was to know that the lower holes as measured up from the bottom of the wheel pant edge are the same distance. So, I made a couple of hole template plates that would key off of the center of the axle bolt pattern. The hardest part was to locate the center of wheel in each pant both in water line and butt line. First, I turned the wheel pant upside down in a fixture and laid a string along the open end fore and aft and measured from each edge to find the center. Then I laid a straight edge along the centerline to find the center fore and aft. Then I transferred the center point on the open end to the side of the pant were the center of the axle would be using a string and plumb bob. I then inserted the wheel with axle nut and center punch inside the axle nut, along with blocks front and back and top to confirm my center point. Once I had my center point, I drilled it, then Clecoded my solid template plate to the side of the pant to locate all of the mounting plate holes. I drilled each hole, one at a time and Clecoed the plate to the pant for each hole. I then Clecoed my cutout pattern plate to the pant to trace the irregular hole for the plate and axle, I used a Dremel and special cutoff wheel disk to cut the hole, then clean it up with a drum sander wheel. I used carbide brad point drills to drill all holes so as not to delaminate the fiberglass layers. The installation when well and the wheels fit in. See photos.

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More photos

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More data

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Note. My wheel pants are such that the bottom of the pant where the wheel fits in is not parallel to the streamline rib that runs longitudinal along the side of the pant. What matters is that the streamline rib is parallel to the airflow rather than the bottom of the pant. Understanding this was important for me to understand the setup. Once I knew this, and the approximate vertical location of the centerline of the axle up from the bottom from the open end of the pant (about 3.1 in) , I had a path forward to finish the job. I got the 3.1 dimension from the Club Member who sold me the carbon fiber mounting plates as he had a spare set of pants in his shop to make some measurements for me. I had only one pair of pants to fit, so I made temporary fixturing to do the job, but if someone was making multiple sets, I could see that a more permanent fixture to place around the pant to hold it square and to locate the mounting holes, including the axle center point would be useful. I have read articles about how the RV builders fit their pants onto the gear, and it can get complex, including the use of lasers to find centerlines and centerpoints.

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Sketches that I made to understand how to locate the wheel pant plate mounting holes once I located the centerline for the axle in the wheel well inside the pant.

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Here are some more progress photos with the aluminum doublers installed where the AN6 axle bolt pierces the side wall of the wheel pant. I used two doublers to sandwich the fiberglass made from 2024T3 Alclad, 2.5 OD x 2.0 Rivet Circle Dia x 0.032 in thick secured with AN470AD-3 rivets, which I squeezed (rather than bucking) to avoid fracturing the fiberglass. I have started applying Polyfiber UV Smooth Prime now to protect the fiberglass from UV. The UV Smooth Prime fills pinholes and sands well. After the UV Smooth Prime cures for 7 days, I will seal with Polyfiber EP-420/430 Epoxy, then top coat with Aerothane.

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One of the other members sent me a private message about what my plans are for wheel pant color scheme. I am not sure if my email made it through the system, so here is my reply.
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I debated the color scheme for my pants, and I am ready to epoxy prime them now having done the UV Smooth Prime regiment and gotten a good surface.

My plan after looking at many photos of other aircraft is to go with a Madrid red pant with a Nevada silver stripe along the longitudinal rib. My aircraft color scheme will be Nevada silver primary with Madrid red trim.

Initially, I debated a Nevada silver pant with a red stripe, but decided the opposite.

I plan to paint the whole pant first red, then mask the stripe area, then re-paint the stripe with red to seal the tape edges to prevent bleed through of the silver. After the tape is sealed, I will apply the silver trim. I've noted the red color covers well, much better than the metallic Nevada silver, so I may need an extra coat of silver to do the trim.

Another way would be to paint most of the pant silver first, use a strip of wide tape to block out the area for the stripe (tape over the dried silver), spray over the tape edges with silver to seal the tape, then paint the rest of the pant red. This may be a better way to get the silver stripe without excessive coats of silver on top of red paint.