Tuesday, May 6, 2014

Vans Aircraft RV-12 Airplane Build, Section 35: Landing Gear & Engine Mount (part 5) & misc jobs

Reference: Page 35-06; 1.5 hours

This last week I had another EAA Technical inspection from a different counselor. Jake my old counselor (retired?) in January of this year. Ernie has inspected at least 14 RV-12 constructions and know a lot about their weak point. So there are a few things I am going to correct and I will list them as they are completed and add them to the GOTCHA list.

The first on is were the wires come through the seat rib for the auto pilot servo. As can be seen in the first picture the wires come through the rib but can rub against the edge of the rib. So i install edge grommet to protect the wires.

Reference page 35-07 (previously page 35-06); SB 10-12-14

Inspected the nose fork per SB 10-12-14 and found no manufacturing defects. Step 1: Attach the WD-1201 Nose Gear Assembly to the fuselage using the hardware called out.

Step 3: Tap 5/16-24 the holes indicated in Figure 2 of the RV-12 plans on page 35-07. Thread screws into the WD-1230 Nose Fork Assembly as shown in Figure 2.

Step 4: Grease the SF 4048-16 Bronze Bushings with Aeroshell #5 or equivalent. Slide the WD-1230 Nose Fork Assembly, the two U-611 Washers, and the NAS1149F2090P Washer (The U-611 washers are "cupped", and to function properly, the outside perimeter of both washers must be in contact with each other when installed) onto the WD-1201 Nose Gear Assembly. Finally, thread on the MS21025-20 Nut.

Step 5: Thread safety wire through the bolt holes used to secure the Nose Wheel and Tire Assembly to the WD-1230 Nose Fork Assembly, then attach a spring scale to the end of the safety wire. Tighten the MS21025-20 Nut until a force of 18-20 lbs is measured as the Nose Fork Assembly pivots around the spindle. Use the nut as a drill guide and drill #30 both sides of the nose gear leg for the cotter pin. Deburr as required then secure the nut with the cotter pin called-out in Figure 2.

Step 6: Slide the U-1210A Axle through the bearings, then slide the U-1210B Spacer over the end of the axle as shown in Figure 3. Bolt the Nose Wheel and Tire Assembly, the axle, and the spacer to the Nose Fork Assembly using the hardware called-out in Figure 3. The Nose Wheel utilizes ball bearings that are prelubricated and sealed. The axle nut need only be torqued so that slight drag is produced from the bearings and then backed off slightly (approximately 1/4 turn). Please note that this is different than the torquing procedure used for the main wheel which has tapered roller bearings with an integral grease seal.

I didn't take any pictures of the mounted wheel. Not sure why. But this completes this entry and the installation of the landing gear with the exception of adding brake fluid and bleeding the brakes on the RV-12 aircraft.