Carburetor Drip Trays Assembled & ELT Bracket Mounted

It won’t be long until the Rotax 912 ULS engine will get prepared for instillation.  In removing the carburetors and intake manifolds to install the required air shroud … during reassembly, the Rotax 912’s carburetors will receive a drip tray.  The drip trays are comprised of four components, the FF-01226A drip tray, FF-01226B & FF-01226C stiffeners and FF-01216D drip tray doubler.  The drip tray and stiffeners are riveted together and after the riveting is completed the drip tray doubler is bonded onto the drip tray with fuel tank sealant.

The FF-01226A drip tray FF-01226B stiffeners require some trimming which was covered in a posting a week or so ago when the parts were prepared for primer.  Prior to assembling the drip trays, the plans instruct the builder to match drill the rivet holes in the upper right flange of each drip tray into the FF-01226B stiffener.

Match drilling the upper right flange on the FF-01226A drip tray into the FF-01226B stiffener using a #40 drill bit.

Next the plans call for machine countersinking the middle rivet hole on the upper left flange of both drip trays and the associated rivet hole in the inside of the FF-01226C stiffener so the rivet set in that location will sit flat on both sides.

Machine countersinking the second rivet hole from the top on the left flange of the FF-01226A drip tray using a #40 100 degree countersink bit. During the countersinking, the stiffener was left clecoed in position so the countersink bit would not elongate the rivet hole.

After the drip tray was machine countersunk, the corresponding rivet hole on the inside of the FF-01226C stiffener was machine countersunk using the #40 100 degree countersink bit. Both drip trays are to be machine countersunk at this same location.

My fingers are pointing to the second rivet hole down on the left flange of the FF-01226A drip tray and the associated rivet hole on the inside of FF-01226C stiffener that received machine countersinking.

The both drip trays were assembled using AN426AD3-3 rivets in the countersunk locations and AN470AD3-4 rivets in the remaining rivet holes.

Using the pneumatic rivet squeezer to assemble the carburetor drip trays using AN470AD3-4 rivets.

Completed riveting of both drip trays … one can see the middle rivet on the upper left flange of both drip trays is flush on both sides … because the associated rivet hole was countersunk on both sides.

The remaining tasks to complete the drip tray assembly requires using fuel tank sealant to bond the FF-01226D doubler onto the drip tray and to also seal the seams and gaps in the drip trays. It was getting on in the evening so decided to hold off and perform that task during the next work session. Because the drip trays only require a tiny amount of fuel tank sealant, decided to prepare a couple of locations that still require sealing so the excess can be used there.

The plans call for sealing the base of the instrument tray with fuel tank sealant to protect from water intrusion. Wanting to strive for a neat look, decided to take the time and mask off the areas with masking tape. This way I will be able to use a syringe to lay down a bead of sealant and then use a shaped wooden stick to tool the sealant and hopefully peal the tape away to create a clean edge …but fuel tank sealant has a mind of its own and may not play nice.

The area all along the base of the instrument panel on both sides of the RV-12 was masked to protect the paint from unwanted fuel tank sealant.

Before heading home for the evening decided, while the rivet squeezer was still out, to install the recently painted F-12122 ELT mounting bracket onto the F-1204F-R bulkhead. The ELT bracket mounts onto the bulkhead using two AN470AD4-4 rivets.

Positioning the pneumatic rivet squeezer to rivet the F-12122 ELT mounting bracket onto the F-1204F-R bulkhead using AN470AD4-4 rivets.