Tuesday, June 28, 2016

Instillation Of The S-1201 Spinner Begins

The euphoria of thinking the propeller installation was complete and good to go was short lived … while reading ahead in the plans, discovered the propeller needs to be removed to complete the spinner instillation. I tried to work around the issue and made great progress … that is until it got time to drill rivet holes for the nutplates on the S-1203-1 spinner bulkhead flange. The angle drill would not clear the spacers under the S-1203-1 bulkhead … so sadly, the propeller blades must come off.

The process of installing the spinner begins with placing tape around the propeller to protect the finish and then placing the spinner in position. It was necessary to do a few on/off cycles for  minor sanding on the S-1201 spinner to clear the propeller blades.
Test fitting the S-1201 spinner after wrapping tape around the propeller to protect the finish.

The spinner alignment begins by making a sighting tool to place in front of the pitot tube to aid in centering the spinner. The camera tripod was enlisted for the job and a ruler was clamped onto the tripod as a sighting aid.
A camera tripod with a ruler clamped onto it is used as a sighting tool to detect the wobble of the pitot tube.

The alignment procedure begins by removing the lower spark plugs so the propeller can be turned easily. The goal is to center the spinner so the pitot tube does not move when the propeller rotates. (The propeller needs to be moved carefully so the airplane does not move … although it will sway on the tires a little but settles when hands are off the propeller blades). I used only two Cleco clamps to begin with one on the top of the spinner and one at the bottom and zeroed the horizontal axis. Next the propeller was turned 90 degrees and the process was repeated ...  when it was perfect, additional Cleco clamps were installed all the way around the spinner to hold it in position for the drilling process.
Sight once the S-1201 spinner was adjusted to center. Placing the propeller in any position resulted in this sight picture after the spinner was completely centered.
Use of Cleco clamps worked out quite well to hold the S-1201 spinner centered for drilling.

The four holes in the S-1203-1 spinner bulkhead are drilled first to #30 and secured with Clecos. After every hole the centering was checked and fortunately the spinner did not move. With the spinner now locked in place with four Clecos in the S-1203-1 bulkhead, the S-1202 spinner plate is drilled beginning with the center holes and working towards the propeller blade cutouts.
All the holes are drilled into the S-1201 spinner … (well almost).
After all the drilling was completed, fortunately the sight gauge was still centered after rotating the prop.

Fellow builders please note: The following photos are not typical in that the propeller was still installed because it appeared a possibility all the work could be done without removing the propeller … but that IS NOT the case, the blades do need to come off to complete all the necessary steps for the spinner instillation ... as I later found out.

Next on the agenda is making gap fillers to cover the slots made for the propeller blades. The two S-1202C gap fillers are made from the scraps that were saved when cutting the blade slots in the spinner. There is a template in the plans that gets the gap fillers to the approximate size, but they still required a lot of extra sanding before clearing the root of the propeller blades nicely. Once the fit was acceptable, the S-1202C gap fillers are clamped to the S-1202 spinner plate and drilled.
S-1202C gap filler clamped in position for drilling.
Drilling the S-1202C gap filler to the S-1202 spinner plate using a #40 drill bit.
Completed drilling of S-1202C gap filler to the S-1202 spinner plate.

For the attachment to the spinner itself, four metal tabs are fabricated by placing a curve in a strip of aluminum to match the spinner’s curvature. Once curved, the strip is cut into 1 ¼" squares. … these squares are used to bridge the gap between the gap fillers and the spinner. Nutplates will be used so the gap fillers can be attached to the spinner.  One of the down sides to using the scraps from the cutout is that there is a gap between the parts from the cutting and the edges seem to taper a bit so the edge that is adjacent to the spinner plate needs to be used as the reference point for laying out the rivet holes.
Installing the S-1202B back plates onto the S-1202C gap filler.

The S-1202B back plates will extend beyond the edges of the gap filler and will need to be cut back. I cut the material back slightly more than necessary so if a little more clearance is desired between the gap filler and the propeller it would be easy sanding without getting into metal. A center line is drawn onto the back plates to aid in drilling the spinner into the back plate. Because the propeller blades were still installed at this point, an angle drill was used to drill through the spinner and into the S-1202B back plate … this hole will be for a nutplate installed later.
My fingers are pointing towards the locations where material needs to be removed from the back plates to clear the propeller.
A center line drawn onto the back plate denotes the drill line for the spinner as can be seen in the photo.

An angle drill being tested for clearance and ultimately used to drill through the S-1201 spinner and into the S-1202B back plates ... (this would not be necessary if the blades were removed as they should be at this point).

Once all the drilling for the gap fillers and back plates was completed, the #30 holes in the spinner are enlarged to #19 beginning with the four holes in the S-1203-1 spinner bulkhead. Clecos for #19 holes were used to keep the spinner positioned. Prior to drilling out the #30 holes in the S-1202 spinner plate to #19 the Cleco clamps were installed to prevent movement while the holes were enlarged and screws were inserted … fortunately, there was no movement.
Drilling the #30 holes in the F-1201 spinner and F-1203-1 bulkhead out to #19.
Drilling out all the holes along the F-1202 spinner plate to #19.

I stopped work short of drilling the rivet holes for the nutplates's on the S-1203-1 bulkhead and F-1202 spinner plate  because it was getting late and there was nobody around the airport to lend assistance with removing the propeller blades ... so will tend to that during the next work session so the S-1202 spinner plate and S-1203-1 bulkhead can be removed for countersinking and riveting nutplates onto them.