Tuesday, April 19, 2016

Lots And Lots Of Sanding On Upper Cowling Half Begins

The work session began by working the excess fiberglass on the upper cowl half down close to the trim lines with 80 grit sandpaper At this point in time, the plan is to only sand down the sides and the front of the upper and lower cowling to the trim line. The goal is to obtain a nice fit centered on the engine with approximately a 1/8" gap between the cowling and spinner back plate that will be mounted on the hub the propeller will attach onto. By leaving the cowling halves slightly long, there should be just a little wiggle room to make tiny adjustments to the overall fit.
Sanding down the upper cowling to the cut line using Dura-Block sanding block and 80 grit sandpaper.

Even though there is only 1/8" of material to remove to get down to the trim lines, it still requires a lot of sanding ... even with 80 grit paper. As can be seen in the above photo, a Dura-Block sanding block was used to sand the cowling … this made it really easy to make the edges straight without ripples. The sandpaper was switched to 150 grit once close to the trim lines to allow for an accurate finish sanding just barely down to the trim line.

About the time sanding on the upper cowl’s front and sides was completed, Mike and Bernie rolled up. On a lark we held the prop spinner plate on the hub and did a test fit of the upper cowling. Have to say, the amount of material on the upper cowling that overlaps the upper fuselage skin is approximately the amount of material in excess of the trim line. It is amazing, but Van’s trim lines are very close to being perfect in length but it looks to me as though the cowling would be skewed ever so slightly to the left. I should be able to correct for that if I want to take the time to do so. Won’t really get a good handle on it until the bottom cowl is sanded down and fitted to the upper cowl.

The work session yesterday was a short one … only had time to sand down the upper cowling prior to getting distracted with Mike’s lawn tractor, which we were able to fix BTW.