Figure 2: Prep & Fill Seam
Figure 3: Seam filled and fared in one area Figure 4: Seam before repair
Section A-2
For good paint adhesion the gel coat shiny surface needs to be abraded with 150 grit sandpaper until there is a matt surface with no shine before the primer coat is applied. Sanding through the gel coat subsurface and into the fiberglass weave is not recommended and will create additional work to fill in pin holes.
2.3 Assemble Landing Gear
Required Parts And Supplies:
2 Landing Gear Skid Tubes 2 Landing Gear Bow Tubes 2 Front Skid Bow Fittings 2 Rear Skid Bow Fittings 2 Front Fuselage Bow Clamps 2 Rear Fuselage Bow Clamps
24 3/16” X 3/8” Stainless Steel Rivets 4 AN42b-17A Eyebolts
4 AN3-5A Bolts
8 AN365-1032A Elastic Lock Nuts 6 AN960-10L Flat Washers
4 Ms20667-3 Stainless Steel Forked Cable Ends 4 Ms20668-3 Stainless Steel Eye Cable Ends 8’ 3/32” Stainless Steel Wire Cable
Parts Fabricated:
2 Landing Gear Stabilizer Cables Notes:
• The landing gear consists of two horizontal skids attached to two transverse bows by four steel fittings. The bows are attached to the fuse-lage by four fiberglass clamps. All attachments use 3/16” stainless steel rivets.
• The steel fitting consists of a tubular collar welded at an angle to a half-round saddle. The two rear fittings will have an additional small tube to receive the axle of ground handling wheels.
• If the landing gear will be used for float opera-tion, the steel fittings should be galvanized, zinc or nickel coated to resist the corrosive effects of the water.
• If the gear is to be used only on land, the fit-tings can be primed and painted.
Procedure:
A) Mark, drill, and deburr a 3/16” hole in each corner of the saddle of the first skid fitting. Each hole should be no less than 3/8” from any edge.
Repeat for remaining three skid fittings.
Figure 5: Landing gear skid and fitting 10” from end of bow.
Figure 6: Landing gear fitting secured to bow and skid with rivets.
SADDLE
Figure 7: Square against the outer horizontal edge of saddle and intersecting circumferential line on bow.
10” BOW
SKID
Section A-2
B) Lay a fitting on one side and mark the center of the tubular collar, no less than 1” from its open end. Drill a 3/16” hole vertically through both walls, and deburr. Repeat for remaining three skid fittings.
C) Fabricate the landing gear assembly jig per Drawing on page A.2-7.
D) Lay landing gear skids next to the jig with the larger curved ends at the front and turned up. Lay bows in jig with their ends closest to the nearest end of each skid.
E) Slide the collar of one of the skid fittings onto one end of a landing gear bow. Rotate fitting as needed to provide a snug fit between saddle and skid. Maintaining that alignment, remove bow and fitting from jig and firmly seat collar onto bow us-ing a mallet or dead-blow hammer. Replace bow and fitting in jig and verify that correct alignment between saddle and skid is maintained. Make adjustments if necessary. Repeat for remaining three fittings.
F) With the skids laying next to the bows with fittings attached, make a mark on top of the skids 10” from the top rear edge. Then place skid into the saddles mounted on bow’s with the mark aligned to the rear edge of the rear saddle. With the ends of the skids positioned in the up position, drill a 3/16” hole in the skid through one hole in the saddle. Deburr the hole and insert a 3/16” X 3/8” stainless steel (SS) rivet through the saddle and into the skid. Repeat for the remaining three fittings. Figure 5 & 6.
G) Re-check fitting alignment and if satisfactory, drill a 3/16” hole in skid through each remaining hole in the skid fitting saddle. Deburr all holes.
Repeat for remaining three skid fittings.
H) Insert and fasten a 3/16” x 3/8” SS rivet in each hole in the skid fitting collar and fasten all rivets. Repeat for remaining three skid fittings.
I) Remove landing gear from jig and invert (fig-ure 9). Drill 3/16” holes in bow through bottom hole of collar. Insert 3/16” x 3/8” SS rivet in hole and fasten collar rivets. Repeat for remaining three skid fittings.
Figure 10: Use straps to preload skid bows for proper cable tension.
Figure 8: Upright landing gear in jig.
Figure 9: Inverted landing gear in jig.
Section A-2
J) Mark a circumferential line around bow 3”
above top of collar. Lay a square against the inner horizontal edge of a skid fitting saddle, with the square rule resting on underside of bow. Position the square such that the circumferential line in-tersects the 6” distance from saddle (Photo) and mark. Drill and de-burr a 1/8” pilot hole in bow.
Repeat for remaining three bow legs.
K) Reinstall landing gear in jig right side up as be-fore. Lay the square against the outer horizontal edge of saddle, with the square rule resting on the upper side of bow. Position the square such that the circumferential line intersects the 6” distance from saddle (Photo) and mark. Drill a 3/16” hole in bow and out through the 1/8” pilot hole on the underside. De-burr both holes. Repeat for remaining three bow legs
L) Install four AN42B-17A eyebolts in bows from below and fasten finger tight with AN365-1032A nuts. Attach an MS20667-3 fork cable end to one eyebolt on each bow with AN3-5A bolts and fasten finger tight with AN365-1032A nuts. Temporarily install both cross cables.
M) Remove gear from jig. Add a 29 1/2” spreader bar (see drawing on page A.2-7) between bows on center. Install a ratchet strap around each skid and draw strap to pull in skids to 60” center to center on skids.
N) Cut a 48” length of 3/32” steel cable and swage an MS20667-3 fork cable end to one end.
Temporarily attach that cable end to an eyebolt with an AN3-5A bolt and stretch the cable to the other cable end on the same bow. Mark the cable at the point where it will enter the other cable end (not swaged). Remove both cable ends. Add 1 1/4” to the mark and trim the cable to that length.
Insert the cable into the cable end until the mark is just inside and swage. Repeat for other bow.
Then temporarily install both cross cables.
Note: When swaging cable ends, tighten swage and strike with a blunt chisel and hammer 2 to 3 times between swage points to ensure the swage is set properly.
MARK CENTER
Figure 11: Mark center of bows and fuselage.
Section A-2
2.4 Attach Landing Gear to Fuselage
Required Parts And Supplies:
1 Fuselage
2 Front Gear Bow Clamps 2 Rear Gear Bow Clamps
21” Bow Clamp Concave Shim Stock
22 3/16” X 3/8” Stainless Steel Rivets (Non-XE3) 10 3/16” X 3/8” Stainless Steel Rivets (XE3 Only) 12 3/16” X 1/2” Stainless Steel Rivets (XE3 Only) 2 AN3-5A Bolts
4 AN4-22A Bolts
24 AN960-10L Flat Washers 8 AN960-416L Flat Washers 2 AN970-3 Fender Washers 2 AN365-1032A Elastic Lock Nuts 4 AN365-428A Elastic Lock Nuts 7’ 3/32” Stainless Steel Wire Cable Parts Fabricated:
4 Landing Gear Stabilizer Cables 4 Bow Clamp Concave Shims 4 Bow Clamp Flat Shims (XE3 Only) Notes:
• The fuselage is attached to the landing gear bows by four fiberglass clamps, two at the rear bow and two at the front bow under the cockpit.
All attachments use 3/16” stainless steel rivets except for two AN3-5A bolts in the front clamps which also anchor gear stabilizer cables and four AN4-22A bolts which anchor the gear bows in the clamps.
• The XE3 model requires shims between the rear bow clamp and the fuselage. 1/2” rivets must be used to accommodate the additional thickness.
Procedure:
A) Make a mark on the center line of the rear of the rear bow and also on the rear surface of the landing gear shelf of the fuselage. Place bow spreader bar (see drawing) between the bows on center line. Next with tail boom removed from fuselage, place the fuselage on top to the landing gear with the two center lines previously marked on rear bow and fuselage aligned. Measure the thickness of the four curved shims provided and sand down or build up until they are 1/8” thick in the center. Place the two curved shims between the top of each bow and the underside of the fuselage, flush with the rear of the gear mount shelf at the rear of the helicopter fuselage. Apply a small amount of RTV clear silicone between the fuselage and curved shims. Figure 12.
Figure 13: Rear bow clamps installed.
Figure 14: Rear bow clamps installed.
Figure 12: Curved shims sanded to 1/8” and bed in RTV silicone.
CURVED SHIMS
Section A-2
Figure 15: Completed landing gear assembly.
B) Install the rear clamps in place around the rear bow with the back of the clamp on the vertical end of the shelf and the front of the clamp under the fuselage. The edge of each clamp should be flush with the outside edge of the shelf.
C) Use a 3/16” drill to drill holes in the corner of each flat surface of the clamp and through the fuselage underneath. Holes should be ½” in from each edge. Use the 3/16 x 3/8” stainless steel blind rivets provided to rivet the clamps in place.
Reach through the hole inside the fuselage to ac-cess the inside of the shelf area and place 3/16”
washers over the rivets before setting them. The washers prevent the rivets from damaging the fiberglass when they are fastened.
D) Place the front bow clamps onto the front bow with the shims between the bow and fuselage.
Figure 12.
E) Drill up through the corner of the clamp 1/2” in from each edge with an 1/8” bit and check align-ment. Once correctly located, drill the remaining holes and rivet in the same manner as the rear
bow with reinforcing washers placed over the riv-ets. Do not place a rivet in the inside rear hole of the two front clamps. These holes will be used for the reinforcement cables.
F) Check to see that the skids are parallel and properly centered along the center line of the fuselage. Drill through the pre-drilled hole in the center of each clamp with a 1/4” bit directly through the center of each bow and install the AN4-22A bolts provided into each clamp.
Figure 14.
G) Bolt the forked cable end fittings onto each of the eye bolts using AN3-5A bolts. Add an eye type cable fitting to the underside of the eye bolt on each side of the rear bow. Bolt eye type cable fittings to the inside rear hole of the front bow clamps using AN3-5A bolts and a washer inside the fuselage.
H) Using the same procedure as used on the cross cables, make and install the two longitudinal cables.
Section A-2
11 1/2”
4”
4”
1/4” Plywood
3/4” Plywood
2 X 4
29 1/2”
SIDE VIEW
4”
4”
2 X 4 1/4” Plywood 3/4” Plywood
11 1/2”
FRONT VIEW
29 1/2”
2 X 2