I had been flying for a couple of years when I finally got around to trying a wing. Up until then, I was flying traditional 3, 4, and 5 channel planes. Some of these were bought as kits while others were built from scratch using foam board and plans from Flite Test. My first wing was a little 36" Popwing from Nitro Planes. It wetted my appetite enough to try another wing. After spending time searching various forums, I decided to try the Gladiator XL kit made by Crash Test Hobby.
The Gladiator XL is a big wing, measuring in at 66 inches. It can be used as a sport plane or as a large FPV platform. It is made from EPP (Expanded Polypropylene Foam) foam that has various uses such as packing material and even bumpers for some cars. It is light weight and extremely durable. In other words, it is good material for making RC aircraft that may be subjected to a fair amount of abuse.
The Gladiator XL kit from CTH does not include any of the electronics needed for flying the plane. The kit does contain everything needed to assemble the wing except for tape and glue. Pre-cut EPP foam wings and center extension, fiberglass spars, Formica motor mount bases, nylon shock cord, control horns, stainless steel motor mount, push rods and guides, laminate, etc. are all included. I purchased an extra roll of laminate when I ordered the kit and I am glad I did. The laminate cost is minimal and having extra allowed me to practice with it before ironing it onto the foam. It also made for an easy recovery if you goofed up while cutting and fitting the laminate.
The CTH website has several construction videos as well as written directions for the Gladiator XL. My recommendation would be to view and study these several times before starting on your first wing assembly. The RC Groups forum also has a section specifically for the large CTH wings and the company's owner is active in the forum group. I've communicated with him on the forum as well as regular e-mail with good results. The comments and photos I've included in this write-up do not cover all the steps necessary to assemble the plane.
I borrowed some long T-pins from my wife's quilting room to hold a wing and the center section in position during gluing. I pinned them onto a piece of scrap Dow Styrofoam, normally used for house insulation. I opted to use Gorilla Glue for this part of the construction. While a generous amount of hot glue would work here, it does add more to the overall weight and since I wasn't in a big hurry, I had time to let the glue cure. A piece of newspaper was put beneath the EPP foam so any spillage wouldn't glue the EPP foam to the Styrofoam. Gorilla Glue expands to fill voids and will easily squeeze out from between the pieces being glued so don't get too liberal with it while applying to the EPP foam.
From my construction notes: Applied glue to edge of center section with q-tip, making sure not to apply too much. Wetted the matching edge of the wing and then pressed the two pieces together after applying a pea sized blob of hot glue at the leading edge of the two surfaces. Held pieces together until hot glue cooled, then proceeded to t-pin the pieces to each other as I worked towards the trailing edge. A minimal amount of Gorilla glue squeezed out of the seam as it dried. Repeat process to attach other wing to center section.
After the other wing was glued to the center section, it was time to create slots in the foam for the fiberglass spars. The spars need to be positioned into the foam so they do not protrude above the foam surface, so the slot is made about 1/4" deep. I had a foam cutting tip for my Weller soldering gun and decided to give it a try, never having used that tip before. Using the recommended measurements from the CTH build page, I traced lines for the spars on both the top and bottom surfaces of the foam. I used a metal ruler as a guide to keep the slots straight. T-pins were used to keep it in place, as seen in the above photo.
From my construction notes: Used soldering gun with foam cutting tip to create slots for spars. Worked very well. It's not as goof proof as what CTH recommends in their build video, but I found it easy enough to maintain a consistent depth of cut for the slot. I used the metal ruler to maintain a straight edge.
Included in the kit is several pieces of 6" long wire. Once you have the slots cut for the spar, bend a piece of wire to fit into a slot where a spar meets up with another spar. These wires help prevent the spars from separating during an accident. They are laid in the slot and then the spar is placed over it. The wire is very stiff so be sure to use a pair of pliers to get a nice, clean bend.
Here is a photo of a wing with the fiberglass spars cut to length and glued into the slots. I used Beacon "Multi-Grip" glue for this step of the assembly. The 4 ounce bottle's applicator makes it easy to get the glue into the slot. It doesn't expand like Gorilla Glue so no mess to worry about there. As I write this, this wing has been flown many times which includes a few not so great landings. The glue has shown no sign of failing.
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