ACE Package - Cowling Top Sides, Bottom & Hardware Kit (Part 4 of 4) **912is, 915is**
SKU:
$970.00
$970.00 - $1,384.00
per item
This kit includes an aluminum cowl bottom, fibreglass lip, aluminum top sides, screws and anchor nuts for mounting the top and bottom cowling in place.
1/4 Turn Skybolt fasteners are an option for the top cowling only and are highly recommended to save you time. They are different hole spacing so they are not easy to install after the screws in this kit have been installed.
1/4 Turn Skybolt fasteners are an option for the top cowling only and are highly recommended to save you time. They are different hole spacing so they are not easy to install after the screws in this kit have been installed.
INSTALLATION INSTRUCTIONS
Dimpling/Rivetting Information:
Below are two videos that explain how to dimple and rivet without specialty equipment.
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STEP 1:
Trim lower forward cheek skins (Lh & Rh) parallel to firewall. Lh shown. Verify nose bowl looks level as fit before.
Lay four rows of tape as shown above on both forward sides of cheek skins (lower half only) and nose bowl fibreglass part only three rows of 3/4" only over the whole thing. This 1.25" line that you have marked on the cheek skins will eventually be your trim line for the bottom cowl on the back side. On the front side, you will eventually trim your lower cowling skin to the edge of the fibreglass (aft edge of the first tape laid).
STEP 2: Fitting of The Lower Cowling Skins
Slide your Lh bottom skin up the exhaust pipe and verify that its corners match the corners of the nose bowl (front) and chin skin (aft).
Enlarge the opening for the exhaust pipe if required. Clamp and tape in place. Verify that the cowling fits to the 1.25" mark or farther on the aft side and extends forward of the edge of the fibreglass nose bowl. Adjust forwards or aft to accomplish this.
On 916, skip the exhaust pipe part, as that will come at the end and your cowl does not have an exhaust hole. Mark a position line on the cowl and nose bowl so that the forward edge of the cowling can be replaced in the same position. Do the same for the aft edge between the cowling and the cheek skin.
Enlarge the opening for the exhaust pipe if required. Clamp and tape in place. Verify that the cowling fits to the 1.25" mark or farther on the aft side and extends forward of the edge of the fibreglass nose bowl. Adjust forwards or aft to accomplish this.
On 916, skip the exhaust pipe part, as that will come at the end and your cowl does not have an exhaust hole. Mark a position line on the cowl and nose bowl so that the forward edge of the cowling can be replaced in the same position. Do the same for the aft edge between the cowling and the cheek skin.
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STEP 3:
Trimming the front vertical edge of the bottom cowling to match the back edge of the fibreglass nose bowl exactly.
Use your tape as a guide by running a tape line directly over your third tape and onto the cowling if it extends that far forward. If Your cowling does not reach the third tape line, run one down the second line. If it did reach, run a second tape line up against the first line you just installed.
Run a second or third tape line (make it 1/2") so the aft edge of the tape line will be 1/4" from your finished cut line.
Remember to only worry about the vertical part and no more than 1" on the bottom (the 6th picture down shows how I marked and cut the bottom part at this time). Do not trim the bottom forward edge farther than 1". Remove the cowling bottom side. Trim to the edge of your tape line. Reinstall and verify that you have a 1/4" overlap.
Run a 3/4" tape down the forward edge of the last (aft) 3/4" tape. This should give you the finish cut line (shown in green on the pictures for the aft side of the cowling).
Run a second tape line exactly against this tape, as when you pull the cowling to make the final cut, the first tape will come off the cowling. The same is done for the aft side, but you want a 1.25" overlap. Remove material till you get to within a 1/4" of your final cut trim. Then, run a 3/4" tape down the 3rd tape from the left, as shown in the picture in step 1. Once again, run a second tape line on the cowling exactly against the first tape edge. Remove cowling and trim both forward and aft sides to the trim line.
HINT: It may be best to file the last bit so you do not get waves in the metal from tin snips. Repeat this procedure for the Rh side; there is no exhaust pipe to worry about. The intake hole center should be about 10.5" aft of the fibreglass on the nose bowl.
Run a second or third tape line (make it 1/2") so the aft edge of the tape line will be 1/4" from your finished cut line.
Remember to only worry about the vertical part and no more than 1" on the bottom (the 6th picture down shows how I marked and cut the bottom part at this time). Do not trim the bottom forward edge farther than 1". Remove the cowling bottom side. Trim to the edge of your tape line. Reinstall and verify that you have a 1/4" overlap.
Run a 3/4" tape down the forward edge of the last (aft) 3/4" tape. This should give you the finish cut line (shown in green on the pictures for the aft side of the cowling).
Run a second tape line exactly against this tape, as when you pull the cowling to make the final cut, the first tape will come off the cowling. The same is done for the aft side, but you want a 1.25" overlap. Remove material till you get to within a 1/4" of your final cut trim. Then, run a 3/4" tape down the 3rd tape from the left, as shown in the picture in step 1. Once again, run a second tape line on the cowling exactly against the first tape edge. Remove cowling and trim both forward and aft sides to the trim line.
HINT: It may be best to file the last bit so you do not get waves in the metal from tin snips. Repeat this procedure for the Rh side; there is no exhaust pipe to worry about. The intake hole center should be about 10.5" aft of the fibreglass on the nose bowl.
Run tape lines on the forward and aft edges where the cowling will eventually fit. The final size of the cowling will be the aft edge of green tape on the aft side and the aft edge of yellow tape on the forward side.
Cut your tape lines off, as shown above. This will give you a 3/4" overlap on the front end. By adding one more 1/2'' tape line to the upper (pictured) row you will be at the 1/4" long mark on the front side, if trimmed to the back edge of the 1/2" tape line.
Slowly trim the front (it is the most important, as you will see it) till it matches the contour on the vertical part of the nose bowl. Once the front is done, trim the aft vertical as well.
If you follow the picture below, you will make the cowling 3/4" extra long. If the yellow tape was replaced with a 1/2" tape, and cut on the forward side of the tape, you would have a 1/4" overlap on the backside as well. I recommend filing the last 1/8'' to keep from getting snip marks in the skin. Finish trimming cowling to final length (aft edge of fibreglass nose bowl and aft edge of green tape on the cheek skin or 1.25" aft of the fwd face of the cheek skin).
Slowly trim the front (it is the most important, as you will see it) till it matches the contour on the vertical part of the nose bowl. Once the front is done, trim the aft vertical as well.
If you follow the picture below, you will make the cowling 3/4" extra long. If the yellow tape was replaced with a 1/2" tape, and cut on the forward side of the tape, you would have a 1/4" overlap on the backside as well. I recommend filing the last 1/8'' to keep from getting snip marks in the skin. Finish trimming cowling to final length (aft edge of fibreglass nose bowl and aft edge of green tape on the cheek skin or 1.25" aft of the fwd face of the cheek skin).
Cut and tape 1/4" wide strips of cardstock paper to the aluminum joiner strip that is immediately aft of the fibreglass on the nose bowl. Build this up until your cowl fits flush with the nose bowl fibreglass. This can be done over the entire nose bowl. Mark the locations on the tape, where you can install fasteners on the fiberglass part of the nose bowl (shown by a circle with an arrow in the picture below).
Place the Lh lower skin in position again. Tape or clamp to the C-channel. Mark a line 9/16" from the front of the skin at the nose bowl and 5/8" from the aft end of the skin at the cheek skin on the bottom cowling skin.
Run a piece of 1/2" masking tape to mark this line using the front or rear edge of the tape as the line. Using the locations you previously marked for fasteners on the nose bowl, mark four holes (close to evenly spaced) on the forward vertical edge of the bottom cowl. Mark the three fastener locations on the aft edge of the lower cowling as well.
Run a piece of 1/2" masking tape to mark this line using the front or rear edge of the tape as the line. Using the locations you previously marked for fasteners on the nose bowl, mark four holes (close to evenly spaced) on the forward vertical edge of the bottom cowl. Mark the three fastener locations on the aft edge of the lower cowling as well.
The top two holes are to go into the C-channel you previously fit when installing the nose bowl. Be sure they are not too high as to make it difficult to install the anchor nuts in the C-channels. Drill these with a #40 and cleco as you go, starting from the bottom corner.
Complete for the Rh side as well.
Complete for the Rh side as well.
Now, fit the bottom front edge of the cowling skins.
This is done the same way as you did the sides, but clamp a straight edge (angle) across the back of the skins so they do not sag down. If they sag down, the cut line at the front edge of the nose bowl changes (see picture above).
Run your 3/4" and 1/2" tape lines till you are 1/4" from the final cut size. Mark the aft side for cutting as well. Trim skins. Reinstall the skins and mark the final trim size. Trim these skins and reinstall.
Mark the 9/16" line at the front and the 5/8" line at the back on your cowling skin. There should be a total of five equally spaced screws at the forward bottom end, with the center screw lined up with the center row of screws in your nose bowl split line. Lay out for two screws on the aft edge - one right close to the edge of the cheek skin and one right close to the outside corner. Drill these with #40 and cleco as you go, working inboard to the center from the corners.
This is done the same way as you did the sides, but clamp a straight edge (angle) across the back of the skins so they do not sag down. If they sag down, the cut line at the front edge of the nose bowl changes (see picture above).
Run your 3/4" and 1/2" tape lines till you are 1/4" from the final cut size. Mark the aft side for cutting as well. Trim skins. Reinstall the skins and mark the final trim size. Trim these skins and reinstall.
Mark the 9/16" line at the front and the 5/8" line at the back on your cowling skin. There should be a total of five equally spaced screws at the forward bottom end, with the center screw lined up with the center row of screws in your nose bowl split line. Lay out for two screws on the aft edge - one right close to the edge of the cheek skin and one right close to the outside corner. Drill these with #40 and cleco as you go, working inboard to the center from the corners.
STEP 4: Cowl Skirt Installation
Mark the inboard edge of the cheek skin on the top side of the cowling skin. This will become your final trim line for the bottom opening.
Position the cowl skirt and clamp it in place. This will replace the angle previously clamped there. The back ends should come to about 5/16" from the bottom chin skin previously installed with your firewall and be centered on the belly of the aircraft.
Mark a line on the bottom cowling halves using the cowl skirt as a guide (shown in the second picture below). This will become part of your cut line. Remove the cowling halves. Transpose the cheek skin line to the outside of the cowling skin on each side. Extend the cowling cheek skin forward till it meets the line drawn from the cowl skirt. This angle is too sharp to cut, so draw a 3" radius to join the two lines. This can now be cut on each cowl half to give the cowling aft opening. Reinstall cowling bottom skins using clecos.
Position the cowl skirt and clamp it in place. This will replace the angle previously clamped there. The back ends should come to about 5/16" from the bottom chin skin previously installed with your firewall and be centered on the belly of the aircraft.
Mark a line on the bottom cowling halves using the cowl skirt as a guide (shown in the second picture below). This will become part of your cut line. Remove the cowling halves. Transpose the cheek skin line to the outside of the cowling skin on each side. Extend the cowling cheek skin forward till it meets the line drawn from the cowl skirt. This angle is too sharp to cut, so draw a 3" radius to join the two lines. This can now be cut on each cowl half to give the cowling aft opening. Reinstall cowling bottom skins using clecos.
Clamp the cowling skirt in position to hold the bottom flat. Draw a line from the cut line in your nose bowl to 1/2" off the center of your nose gear leg on the Rh lower cowl skin. This is your cut line.
To the right of this lay out a double row for rivets 1" apart at approximately 1" spacing. They should start at about 3/8" from the cut line you just drew. Make sure your first rivet holes miss the aluminum strips riveted to the nose bowl.
Run these rivets up to and on the center of the cowling skirt flange. I trim the skirt flange to about 3/4" width to look nice. A slight adjustment of the rivet spacing may need to be made to accommodate this. Layout for rivets at approximately 1" spacing on the cowling skirt starting with the rivets spacing you just laid out. The last aft hole on each side will become a screw. Once again, the hole spacing may need to be adjusted. Be sure the last rivet does not come in contact with the fuselage cheek skin. File cheek skin out as required.
Drill #40 and cleco as you go through all the holes you just marked.
Remove the cowling skins from the aircraft. Trim the Rh skin to the line marked above. The Lh skin can be trimmed to 3/8" from the last row of holes drilled in it.
Place the cowling doubler angle on the inside of the Lh cowling skin so that the angle is even with the cut just made. Clamp and back drill the double row of holes just drilled in the two skins. Trim the aft end to match the opening in the cowling. Cut the vertical part of the angle at a 45-degree angle. Trim the Lh side of the doubler angle to give a 3/8" edge distance.
Deburr all holes. Dimple the double row of holes in the doubler angle, and each lower cowling side skin except the last two holes as they go through the cowling skirt. Countersink (100-degree) the cowl skirt to accept the heads of the 3/32 rivets supplied. They should just sit flat. Do not over countersink.
At this point, if you are doing a 916is, go to the 916 instructions to fit your exhaust pipe to the Lh side of the lower cowling.
To the right of this lay out a double row for rivets 1" apart at approximately 1" spacing. They should start at about 3/8" from the cut line you just drew. Make sure your first rivet holes miss the aluminum strips riveted to the nose bowl.
Run these rivets up to and on the center of the cowling skirt flange. I trim the skirt flange to about 3/4" width to look nice. A slight adjustment of the rivet spacing may need to be made to accommodate this. Layout for rivets at approximately 1" spacing on the cowling skirt starting with the rivets spacing you just laid out. The last aft hole on each side will become a screw. Once again, the hole spacing may need to be adjusted. Be sure the last rivet does not come in contact with the fuselage cheek skin. File cheek skin out as required.
Drill #40 and cleco as you go through all the holes you just marked.
Remove the cowling skins from the aircraft. Trim the Rh skin to the line marked above. The Lh skin can be trimmed to 3/8" from the last row of holes drilled in it.
Place the cowling doubler angle on the inside of the Lh cowling skin so that the angle is even with the cut just made. Clamp and back drill the double row of holes just drilled in the two skins. Trim the aft end to match the opening in the cowling. Cut the vertical part of the angle at a 45-degree angle. Trim the Lh side of the doubler angle to give a 3/8" edge distance.
Deburr all holes. Dimple the double row of holes in the doubler angle, and each lower cowling side skin except the last two holes as they go through the cowling skirt. Countersink (100-degree) the cowl skirt to accept the heads of the 3/32 rivets supplied. They should just sit flat. Do not over countersink.
At this point, if you are doing a 916is, go to the 916 instructions to fit your exhaust pipe to the Lh side of the lower cowling.
STEP 5: Assembly
Rivet the four pieces that make up the lower cowling together.
Cleco the bottom cowl into position.
Starting in the middle, upsize the #40 screw holes to #10 holes and cleco as you work your way evenly outboard and up. Start on the aft row as well, so you finish at the top on each side, front and back, at the same time. Drill the hole in the cowling skirt at this time if you have not already done so.
Mark the lower cowl sides even with the top of the C-channel. This can be cut here, or, if you have the equipment, cut it 5/16" away from the line and put a 90-degree bend in it so it folds over the C-channel. This adds rigidity, and you are less likely to snag on it.
Pick up the center hole in the sides of the bottom cowl. This hole is in the steel bracket attached to the stainless rods. Forward one has a screw already, and the other hole needs to be picked up in the cowl skin on each side.
Remove the bottom cowl assembly, drill for and install anchor nuts in the nose bowl and cheek skins, leave the card stock shims in place until the side cowlings are completely fit, and countersink rivet holes so the rivets are proud (sticking up slightly).
The top three holes in the cowl on each side need to be dimpled for a #10 screw. Remove the cowl C-channels. Dimple the forward and aft holes in the cowling and the C-channel, as well as the middle hole if it is not already dimpled for a #10 screw.
Install anchor nuts on the forward and aft holes just dimpled in the C-channels. Be sure to use the correct anchor nuts for dimpled screws.
You can now file an extra 1/16" off the front of the bottom cowling, all the way around, till you have a nice even gap between the cowling and the nose bowl. This gap should give enough room that the paint will not be chipped off every time you try to remove or install the cowling.
On the 915 engine, be sure you have a minimum of 5/16" clearance between the exhaust pipe and the cowling. Check after running the engine (first run and again after the first flight) for wear marks and trim more as required. Repeat as required.
The bottom cowl can now be screwed into position, ready for the top side cowling installation. Do not overtighten the forward screws, as it could deform the aluminum bottom cowl since it is not supported all around the fastener, just a 1/4" at the front where you have previously shimmed it. You can also go to Induction Connection kit for installing the air filter, scoop and temperature sensors on the Rh side of the bottom cowling.
Cleco the bottom cowl into position.
Starting in the middle, upsize the #40 screw holes to #10 holes and cleco as you work your way evenly outboard and up. Start on the aft row as well, so you finish at the top on each side, front and back, at the same time. Drill the hole in the cowling skirt at this time if you have not already done so.
Mark the lower cowl sides even with the top of the C-channel. This can be cut here, or, if you have the equipment, cut it 5/16" away from the line and put a 90-degree bend in it so it folds over the C-channel. This adds rigidity, and you are less likely to snag on it.
Pick up the center hole in the sides of the bottom cowl. This hole is in the steel bracket attached to the stainless rods. Forward one has a screw already, and the other hole needs to be picked up in the cowl skin on each side.
Remove the bottom cowl assembly, drill for and install anchor nuts in the nose bowl and cheek skins, leave the card stock shims in place until the side cowlings are completely fit, and countersink rivet holes so the rivets are proud (sticking up slightly).
The top three holes in the cowl on each side need to be dimpled for a #10 screw. Remove the cowl C-channels. Dimple the forward and aft holes in the cowling and the C-channel, as well as the middle hole if it is not already dimpled for a #10 screw.
Install anchor nuts on the forward and aft holes just dimpled in the C-channels. Be sure to use the correct anchor nuts for dimpled screws.
You can now file an extra 1/16" off the front of the bottom cowling, all the way around, till you have a nice even gap between the cowling and the nose bowl. This gap should give enough room that the paint will not be chipped off every time you try to remove or install the cowling.
On the 915 engine, be sure you have a minimum of 5/16" clearance between the exhaust pipe and the cowling. Check after running the engine (first run and again after the first flight) for wear marks and trim more as required. Repeat as required.
The bottom cowl can now be screwed into position, ready for the top side cowling installation. Do not overtighten the forward screws, as it could deform the aluminum bottom cowl since it is not supported all around the fastener, just a 1/4" at the front where you have previously shimmed it. You can also go to Induction Connection kit for installing the air filter, scoop and temperature sensors on the Rh side of the bottom cowling.
STEP 6: Fitting The Side Cowling Skins
Run a tape line from the back edge of the fibreglass center cowling down to the back edge of the lower cowling. Make it a smooth-looking arc. This will become your final trim line for the aft edge of the cowling. Repeat on the other side. Add an additional couple of tape lines aft of that so you have a guide for trimming and fitting.
Your fastener row will start at 1/2" at the top and grow to 5/8" at the bottom to line up nicely with the bottom cowling on the aft side.
Place a tape line going down the center of the screws in the C-channel on each side where the top cowling fasteners are going to eventually be located. Place a second and third piece of 3/4" tape below that to help you with the trimming later.
Find the center of the flange for the side cowling to fit onto the center top fibreglass cowling. Mark where you are going to place your fasteners. Be sure there is no interference with the center support bracket. The last fastener will be in the space previously left in the U-channel at the back of the center cowl a few inches from the very aft end. Position an additional 5 fasteners at equal spacing in front of it. The very forward or seventh fastener will be installed in the stainless nose bowl doubler, slightly outboard of the row in the center cowling. Make some marks, tape lines, etc., so you can drill in the center of the flange when the cowl skin is in position.
Check with a straight edge that the top skin is parallel from the nose bowl to 1.25" aft. If you did not flute the back skin when the nose bowl to side cowl strips were installed, you will have to do so now. Be sure not to flute where a cowling fastener is to be located or flute past where the cowl skin will cover.
Position and tape the side skin in place so that it overlaps at least one of the tape lines on the nose bowl and gives at least 1" overlap at the top with 1.25" overlap at the bottom. If this can not be done, you may have to take a 1/8" off either the forward or aft inboard end, tapering to zero at the other end. If the cowl fits better when moved inboard, take up to 3/4" off the inboard end. Verify there is an edge distance on the bottom by the C-channel before cutting. This can be repeated as long as you have an edge distance.
Drill the 6 holes through the cowling and the center fibreglass with #40, cleco as you go. This ensures the same positioning of the skin.
Your fastener row will start at 1/2" at the top and grow to 5/8" at the bottom to line up nicely with the bottom cowling on the aft side.
Place a tape line going down the center of the screws in the C-channel on each side where the top cowling fasteners are going to eventually be located. Place a second and third piece of 3/4" tape below that to help you with the trimming later.
Find the center of the flange for the side cowling to fit onto the center top fibreglass cowling. Mark where you are going to place your fasteners. Be sure there is no interference with the center support bracket. The last fastener will be in the space previously left in the U-channel at the back of the center cowl a few inches from the very aft end. Position an additional 5 fasteners at equal spacing in front of it. The very forward or seventh fastener will be installed in the stainless nose bowl doubler, slightly outboard of the row in the center cowling. Make some marks, tape lines, etc., so you can drill in the center of the flange when the cowl skin is in position.
Check with a straight edge that the top skin is parallel from the nose bowl to 1.25" aft. If you did not flute the back skin when the nose bowl to side cowl strips were installed, you will have to do so now. Be sure not to flute where a cowling fastener is to be located or flute past where the cowl skin will cover.
Position and tape the side skin in place so that it overlaps at least one of the tape lines on the nose bowl and gives at least 1" overlap at the top with 1.25" overlap at the bottom. If this can not be done, you may have to take a 1/8" off either the forward or aft inboard end, tapering to zero at the other end. If the cowl fits better when moved inboard, take up to 3/4" off the inboard end. Verify there is an edge distance on the bottom by the C-channel before cutting. This can be repeated as long as you have an edge distance.
Drill the 6 holes through the cowling and the center fibreglass with #40, cleco as you go. This ensures the same positioning of the skin.
Trim the forward and aft edges of the side skin to within 1/4 " of the final trim line as before on the lower cowling. Trim to the final size, starting from the top (inboard) and working down (outboard).
Place a tape line 9/16" from the fibreglass nose bowl for your fastener row on the forward side fasteners. Your aft row will follow the 1/2" to 5/8" line marked earlier. Mark your forward fastener holes spacing out. The inboard fastener goes in the stainless nose bowl bracket. The outboard most hole is about 1" above the top of the C-channel. There should be 5 equal spaces and 4 fasteners located between the two.
The aft row will have 6 fasteners total. The bottom outboard hole will be about 1" above the C-channel and there will be 6 equal spaces between it and the last hole in the fibreglass center cowling.
Mark your center line for the fasteners in the C-channel using the tape lines previously laid down. Place one near the front so it does not interfere with the anchor nut plate for the bottom skin top screw. Lay out 5 equally spaced fasteners total on the bottom going into the C-channel (be sure not to make them too high where you cannot reach them to install later). Drill and cleco these with a # 40.
Place a tape line 9/16" from the fibreglass nose bowl for your fastener row on the forward side fasteners. Your aft row will follow the 1/2" to 5/8" line marked earlier. Mark your forward fastener holes spacing out. The inboard fastener goes in the stainless nose bowl bracket. The outboard most hole is about 1" above the top of the C-channel. There should be 5 equal spaces and 4 fasteners located between the two.
The aft row will have 6 fasteners total. The bottom outboard hole will be about 1" above the C-channel and there will be 6 equal spaces between it and the last hole in the fibreglass center cowling.
Mark your center line for the fasteners in the C-channel using the tape lines previously laid down. Place one near the front so it does not interfere with the anchor nut plate for the bottom skin top screw. Lay out 5 equally spaced fasteners total on the bottom going into the C-channel (be sure not to make them too high where you cannot reach them to install later). Drill and cleco these with a # 40.
STEP 7:
On the Lh side you can now install the oil access door. See instructions for "Cowling access door Kit (5.25x8 inch opening)" under optimization kits. Install the fuse box cooling scoop in the Lh side cowling. See fuse box mounting and cooling kit for instructions.
STEP 8: Side Cowl Fasteners
With the side cowlings in position, upsize all the #40 screw holes to #10 for screws and anchor nuts or 1/4" for Skybolt fasteners (see note below). Cleco as you go.
Remove the cowling and deburr holes. You can now file off 1/16" from the front edge to give paint clearance, as you did earlier on the bottom cowling. Take your time and make the line nice, straight, and even. This will be seen by everyone.
Use a screw and anchor nut to drill for anchor nut installation. Do not install anchor nut rivets through the bottom cowling when installing in C-channels. Countersink the holes in the top forward and aft sides slightly proud (sticking up slightly).
NOTE: If you are installing 1/4 turn Skybolt fasteners, use one to pick up the two #40 rivet holes. Remove the fastener and receptacle. Upsize the main center hole to 5/16". Deburr the holes. Countersink the proud rivet holes. Install 1/4 turn nut plates. Be sure to upsize the correct holes in the bottom cowling to 5/16" as well, but do not rivet the receptacle to the bottom skin, just the C-channel.
Once your cowling is painted, install 1/4 turn fasteners. Adjust the length of each receptacle as per Skybolt installation instructions on their website after installing a bead of (Proseal 1422B-2, CS3204B2 or equivalent).
FOR ALL INSTALLATIONS
Place a bead of Proseal (1422B-2, CS3204B2 or equivalent) on the forward and aft edges of the nose bowl and tub cowl skins where the cowling overlaps. I also place a thin, even layer on the top and bottom of the side cowling (shown in the second picture below). Smooth this out to replace the cardboard shims used to fit the cowling.
It also fills in the divots caused by crimping the metal. Soapy water keeps it from sticking to things when you are smoothing it out. Once this has dried for a day or two (it should be a rubber consistency like a tire), rub it with baby powder so it will not tend to stick to the cowling (be sure to remove the unlock pin when finished adjusting the fastener length for the 1/4 turn fasteners).
Remove the cowling and deburr holes. You can now file off 1/16" from the front edge to give paint clearance, as you did earlier on the bottom cowling. Take your time and make the line nice, straight, and even. This will be seen by everyone.
Use a screw and anchor nut to drill for anchor nut installation. Do not install anchor nut rivets through the bottom cowling when installing in C-channels. Countersink the holes in the top forward and aft sides slightly proud (sticking up slightly).
NOTE: If you are installing 1/4 turn Skybolt fasteners, use one to pick up the two #40 rivet holes. Remove the fastener and receptacle. Upsize the main center hole to 5/16". Deburr the holes. Countersink the proud rivet holes. Install 1/4 turn nut plates. Be sure to upsize the correct holes in the bottom cowling to 5/16" as well, but do not rivet the receptacle to the bottom skin, just the C-channel.
Once your cowling is painted, install 1/4 turn fasteners. Adjust the length of each receptacle as per Skybolt installation instructions on their website after installing a bead of (Proseal 1422B-2, CS3204B2 or equivalent).
FOR ALL INSTALLATIONS
Place a bead of Proseal (1422B-2, CS3204B2 or equivalent) on the forward and aft edges of the nose bowl and tub cowl skins where the cowling overlaps. I also place a thin, even layer on the top and bottom of the side cowling (shown in the second picture below). Smooth this out to replace the cardboard shims used to fit the cowling.
It also fills in the divots caused by crimping the metal. Soapy water keeps it from sticking to things when you are smoothing it out. Once this has dried for a day or two (it should be a rubber consistency like a tire), rub it with baby powder so it will not tend to stick to the cowling (be sure to remove the unlock pin when finished adjusting the fastener length for the 1/4 turn fasteners).
This shows the proseal rub strip on the top and bottom edge of the Rh cowling.
