Chapter 9 deals with building the Main landing gear. The strut was purchased from Featherlight because this part is made in a mold with numerous layups. The part needs to be precisely made and would be difficult, at best, to make in the ol’ airplane factory.
3/16/02 - Sanded, cut glass, laid up, and peel plied front landing gear bulkhead reinforcements per instructions. 4.5 hrs.
3/17/02 - Sanded, cut glass, laid up, and peel plied bulkhead reinforcements between landing gear bulkheads per instructions. 4.7 hrs.
3/25/02 - Trimmed front and rear landing gear reinforcement layups. Drilled out 1/4" landing gear holes in bulkheads. Drilled out center seat belt attachment tube. 1.5 hrs.
3/29/02 - Cut glass for all 3 reinforcing layups and sanded area between rear LGB and firewall. 1.7 hrs.
3/30/02 - Laid up and peel plied 3 reinforcement layups between rear LGB and firewall. 3.1 hrs.This picture shows all 3 reinforcement layups between the front and rear landing gear bulkheads, and the firewall.
4/18/02 - Sanded shine and flashing off of main gear strut. 2 hrs.
4/19/02 - Measured and cut main gear leg to 95" with 8-degree angle. Cut glass for first reinforcing lay up. Mounted strut on work bench in preparation for layup. 2.5 hrs.The strut is manufactured long to provide room for a cut of 8 degrees at the bottom of the legs. The gear is swept forward so this is the reason for the angled cut. This glass is extremely tough. (has to handle those carrier landings!!) The plans say to use new hacksaw blades.....and Nat isn't joking. The wood block was used as a guide for the blade.
4/20/02 - Laid up first 4 layer reinforcements for landing gear strut. Peel plied. 4.5 hrs.Here the strut is mounted on nail heads so reinforcing layups can be applied. The glass fibers all go lengthwise when the strut is manufactured. These layups are angled to hold the main fibers from coming apart in a hard landing.
4/26/02 - Removed peelply and sanded leading edge and entire landing gear strut. 1.5 hrs.
4/28/02 - Mounted gear strut to bench for 2nd reinforcing layups. Cut 4 strips of uni for layups. Cleaned shop. 1 hr.
4/29/02 - Inventoried Wicks order for Chapters 9-12. Cut remaining uni for gear leg reinforcement layups. 1.5 hrs.
4/30/02 - Fabricated 4 MG-1's and 4 MG-2's. 1.7 hrs.Here I am making the plates (Mg-1 & 2's) that will attach the gear to the fuselage as shown on the right. The drill press made quick work of them!
5/3/02 - Laid up second 4-ply landing gear reinforcements and peel-plied. 4.5 hrs.
5/4/02 - Trimmed layups on landing gear. Fabricated landing gear jig box and bondoed to strut. 5 hrs.This picture shows the gear jigged in place so the attachment tabs can be fabricated in the proper location. The strut is resting on a 2x4 because the garage floor is not level. The board behind the gear simulates a vertical surface. Notice the bottom of the gear is out away from the vertical plain. This simulates the sweep of the gear once it is installed in the fuselage. The jig box that is on top of the strut will guide me in the proper placement of the tab layups. I was not happy with the first jig so I rebuilt it and got a much better fit the second time....oh well, they keep saying this is an educational experience!
5/5/02 - Rebuilt gear leg jig box. Mounted jig box on workbench. Made all measurements for sweep and levelness. Cleaned shop. 3.5 hrs.
5/6/02 - Marked strut and jig box for layups. Sanded strut. Made spacers for layup clamps. 2 hrs.The strut is mounted to the workbench for the tab layups. The strut is first checked for level (at left), and then a plumb bob is hung off the front of the gear leg and lined up for sweep. (at right)
5/9/02 - Cut and taped 2 - 1X6's to be used as clamps for gear tab layups. Cut glass (uni and bid) for gear tab layups. 1.5 hrs.
5/10/02 - Laid up first 45 ply of uni/bid for main gear attach points. 3 hrs.At left, the strut is ready for the first layup. This will consist of 45 layers. The tab will ultimately be 90 layers thick! The small blocks of wood on the jig box are exactly 1/4" thick and a board is clamped in place after the layup guaranteeing a 1/4" tab at this point as shown in the right hand picture.
5/12/02 - Made jig for LG tab hole location. Drilled LG tabs and trimmed all 4 tabs. 4rs.
5/13/02 - Cut glass for inside 45 ply tab layup. Made 4 wood blocks for clamping layups. Sanded inside of tabs and strut for layups. 1.5 hrs.
5/14/02 - Laid up inside 45 plys on LG tabs. peel plied. 3.5 hrs.The second layup is done like the first. Here I am drilling out the tabs for the attachment hardware to be installed. The two tabs combined equal a full 1" of fiberglass that needs to be drilled.
5/16/02 - Trimmed 2nd layup on LG attach tabs. Inverted fuselage and leveled. Dropped plumb lines from aft firewall and front of F22. 2 hrs.
5/17/02 - Laid out string for centerline of fuselage. Trimmed gear opening in fuselage for gear clearance. Started to fit gear strut into fuselage and slotted front and rear bulkheads to adjust for sweep and level. 3 hrs.
5/18/02 - Completed adjustment of gear strut for sweep and levelness. Indexed MG1's and MG2's. Bondoed MG1's to bulkheads and removed 1/4" dowels. Fitted MG2's in place. Drill 16 #10 holes through bulkheads and MG1's per instructions. Opened MG2's to 5/8". 4.5 hrs.Here you can see the MG1's, 2's, and MKMGA trial fitted into the bulkhead area.
5/19/02 - Drilled out LG attachment tabs to 3/4". Drilled out Ft. and R. landing gear bulkheads and MG1's to 5/8". Fitted MKMGA's into strut tabs. Fitted 4 MKMG4 bushings into MG1's and MG2's. Cut landing brake from bottom of fuselage. 3 hrs.
5/20/02 - Measured sweep on gear legs. Measurements out of tolerance. Started adjusting gear. Still not correct. 2 hrs.
5/22/02 - Contacted Nat Puffer (designer) on how to proceed to get gear into spec. He suggested to slot the rear MG1/2 assemblies down and flox holes and redrill in proper location. .2 hrs.
5/23/02 - Slotted MG1/2 holes measured gear and are in tolerance. Floxed first set of holes. 2 hrs.
5/24/02 - Installed MG1/2's drilled out 2 holes in proper location. Floxed other two holes and main bushing holes in rear bulkhead.
5/25/02 - Drill out 2 remaining holes and bushing hole in rear bulkhead. Alodined all MG1/2's and outside seat belt anchors. 1.5 hrs
5/27/02 - Leveled fuselage. Floxed MG1's, 2's, and bushings in place. (2hrs. in morning) Floxed MKMGA's into main strut and mounted into fuselage. Fabricated LB 19 and 23 from 1/4" birch. (2 hrs. @ night.) 4 hrs.
5/28/02 - Cut and shaped foam for MKMGA. Cut and laid up glass for 2 ply bid over MXMGA. Floxed washers over outside attach tabs. Laid up 2 ply bid over each washer. Peel plied. 3 hrs.
5/29/02 - Trimmed final layups on main gear. Cleaned garage. Gear completed. 1 hr.Here is a closeup of the final gear tab ready for install into the fuselage.
6/3/02 - Cut, fitted, and shaped foam for landing gear cover. Cut and laid up 2 ply bid on inside of NACA duct portion of cover. 3 hrs.
6/4/02 - Trimmed layup on inside of scoop on cover. Made flox corners. Cut and laid up 2 ply on outside of scoop. 2 hrs.
6/5/02 - Released LG cover from fuselage. Trimmed cover to fit. Sanded foam for inside layup. Sanded bulkheads clean of foam and 5 min. epoxy. Cleaned garage. 3.5 hrs.Here is the inside of the gear cover after glassing.
6/6/02 - Cut glass and laid up inside of LG cover. Routed 1/16" on LB19. Trimmed landing brake hinge to 10". Trimmed LG cover while in green stage, mounted on fuselage and weighted down for proper alignment during cure. 3hrs.
6/7/02 - Sanded LG bulkheads. Taped LG cover for release. Flipped fuselage over. Cut and laid up 6 ply bid for LG cover mounting ledge. Peel plied layup. Cut out 4 landing brake slugs from 1/4" aluminum. 3 hrs.This picture shows the layup for the inside ledge that the landing gear cover will bolt to........Thanks go to Wayne Hicks for this solution to the "dreaded joggles" This went very quickly and looks very professional!
6/8/02 - Removed LG cover from flange layup. Trimmed flanges. Located centerline for LB hinge. Made slot for LB23 location. 5 min. slugs to LB23. 5 min. LB19 to hinge. Placed LB23 & hinge in fuse. Trimmed foam on brake for LB19 placement. Floxed LB19 to brake. 5 hrs.
6/9/02 - Microed LB23 into fuselage. Routed 1/8" foam from landing brake area per plans. 2 hrs.
8/3/02 - Measured and cut slot for landing brake. Prepared foam, cut glass, and laid up inside of landing brake well. Cleaned garage. 5.5 hrs.Here is the speed brake depression with LB 23 support installed, and slot cut for electric speed brake actuator.
8/4/02 - Shaped foam, cut glass, laid up, and peel plied inside of speed brake. Knife trimmed in weighted in place after 4 hours for final cure. 5 hrs.
8/5/02 - Drilled and tapped hinge holes in LB-23. Fabricated 2 LB-18 brackets for brake door. 2 hrs.
8/6/02 - Located, drilled holes, and mounted LB 18's to speed brake. Started figuring out geometry for electric speed brake actuator and where to mount on seat back brace. 3 hrs.
8/9/02 - Figured mounting points for speed brake actuator. Drilled mounting holes, shortened mounting tubes, laid up reinforcing plys on each side of speed brake mounts 2.5 hrs.
Mounting the actuator took way too long for me. I guess my geometry is a little rusty. It seemed every time I went for more angle to the speed brake, the brake wouldn't fully close, if it did close, the mount ended up interfering with the map pocket (it didn't help that I was doing this with the fuselage upside down). I ended up with a good compromise with a brake that will open to 75 degrees.
I have left the installation of the axles, hubs, and brakes for a December/January install. It is tough to get the garage up to "Layup temperature" during the winter months so I'm putting off mechanical assemblies until then.
Here are the backing plates that the axle bolts go through on the back side of the gear leg.
Here I am sighting through a 1/4" tube at the "X's" on the opposite wall. The plans give you a formula to follow that tells how far from the center of the fuselage to place the "X's" on the opposite wall.
Here the plates are floxed into place and held with a clamp. I did not flox the axles to the gear leg. I wanted the flexability of toe-in adjustment.
At left you can see what I had to repair. The plate was not perpendicular to the bolts. At right is the completed Axle, caliper, hub, and tire.
The left picture shows the assembly of the brake lines. The bulkhead fittingsfor the fuselage are shown at right.
Here us the brake line routed down the back side of the gear leg to the caliper.
Many builders have suggested adding heat shields to the main gear strut. They block the heat from the brake calipers. I guess there are a few incidents where hard braking has transferred enough heat to the fiberglass strut that it has melted and deformed. There is even one case where a plane burned to the ground.
To make these shields, I used 1/8” aluminum and made them a half inch higher and wider than the brake disc area that is exposed to the strut. It took me a couple of hours to complete the whole job, including mounting the wheel/caliper assembly. Cheap insurance.