Cozy Construction Chapters.
Chapter 9 Landing Gear Strut, brakes, wheels, air brake, cover...
Started 05/29/2005 finished 01/19/2006 Finished. Hours worked this chapter :139.5 Holding off on running the brake lines until the nose is complete where the lines connect to the brakes master cylinders.
Start this chapter by adding Landing Gear reinforcement lay up.
In this picture you can see I have already drilled the torque tube holes in the landing gear bulk head. After this lay up I knife trimmed the holes open.
Inside the Landing Gear bay.
Firewall and bulkhead lay up.
The strut is glassed with the peel ply
The mess after the first lay up.
A little 5 minutes epoxy and some Mc D straws taped in place.
This step was made easer by reading Rick Maddy's builder web site, he said lightly sanding the straws before hand which helps the epoxy hold better. Thanks!
I used the book method, which calls for aluminum foil taps the kind used on air conditioning duck work. I had 6 layer of tap enough to make it good and stiff.
Ready for the second lay up, you can see the Mc Donald's straws I used for the brake line conduit.
You can just see the nails I used to hold the strut in place. As I have read in other builders web sites they added a block of wood in increase the height off the workbench. This was a great plus that I recommend. The strut is covered with the second lay up and peel & ply.
Strut is set up in the jig box, glass cut ready to do the tabs.
Marked out the locations of the tabs on the jig box.
After all this work the clamping was to aggressive and the layers slid during cure. One thing about glass is that you can cut it off before it's fully cured and do it again. Next time I will use one long board on each side with less clamping pressure.
Second time around was the charm.
True and parallel next I drilled the pilot holes and removed the jig box and cut the tabs to proper size.
The tabs are drilled and cut to proper size
You can see the 1/4 pilot hole, inside is sanded ready for the inside lay up.
The size of the glass was larger than needed as called for in the book, even after I reduced the size by several inches it's still was a bit to much.
Inside tab before trimming.
Here is the inside tabs after trimming and sanding off any rough spots.
One thing I learned was to make sure that each layer was dry, because as you add layers the epoxy builds up and can make the lay up to epoxy rich. I used the 5 layer on wax paper process and made sure that there where dry spots which would pull in any extra epoxy. Squeegee between each layer helps remove and distribute the epoxy.
Here are some shots of the plats with the 1/4 pilot hole. Floxed in place waiting for cure.
Once the strut tabs where finished I bored out the plats as called out in the book and mounted the bushings. Everything lined up, what a bit of luck, I was kind of worried I had missed something. It would of bend very difficult to fix.
Final tab lay up with bushings in place.
Fit foam to fill the gap, macro in place, also you can see the dimpling on the MKMGA under the bid glass. Finished the tabs by trimming the excess glass now ready test fit.
Here you can see the laser level I used to make sure that the strut and axle mounting hard point are level and true with the proper amount of toe in. The toe in is very important this keeps the strut from splaying during landing and normal operation. If you have to much toe in the wear on the wheels will be excessive.
These two picture show the wood used to make the flat area on the strut where the axle will be located. In this step you make sure that the toe in is set. After cure you can sand it during the fine tuning process.
This is the hard point on the inside of the strut.
These next two picture you can see the strut has been cut to accommodate the axle and brake. You can also see the surface has been sanded to set the toe in alignment.
The black outline is the axle base, I used it to make sure I removed just enough of the strut for the brake.
In this picture show the axle is mounted and the toe in is checked again. At this point you also fit and mount the brake system.
Wheel and brakes mounted, I will finish the brake line and add the heat protection later, most likely during assembly in the fuselage.
Test fit and check of toe in using the laser and the tick marks on the door you saw earlier.
Strut finished waiting to be mounted in fuselage. This will happen once the nose gear is finished.
After shaping the foam the NASA scoop area is glassed.
The NASA scoop near the landing gear not yet shaped to the fuselage. (Camera failure cause blur)
Cover shaped and test landing gear fit.
Cover glassed with flox edges.
Screw holes with counter sink finished.
Starting the speed brake removed from fuselage. Here I made it easer on myself by take the suggestion from other builders web site and cute the glass while it was still green, leaving some points to hold it in place.
Here I am testing the linear motor, I need to find the full cycle limits to determine the location of the hard point. The hard point is made from 1/4 aluminum with a plywood face plate just like the hinge hard point called out in the book for the hinge.
I floxed in the hard point you can see the white dots are silicon plugs that will prevent epoxy from entering the bolt holes. Once the 4 layer reinforcement is cured I just drilled out the glass and then pick out the plugs, it worked nice.
Here is the finished inside. I got the Linear Actuator from Firgelli-Automations.
Here are some picture of the finished outside, I made the wood insert 1/2 inch wider than called for, glad I did.
Here are the parts for the landing bulk head cover. I used a paint can to determine the size of the two holes. Not much detail in the book.
Installed landing gear bulkhead, after cure I cut out the holes and remove some foam from the edges of the hole to make room for some flox.
Landing gear bulkhead covers.
Landing gear covers installed.
On to Chapter 10
This site was last updated 05/22/14