Tom's RC Simulator - RC Projects

WindSurfer
2m High Performance Glider

August '02

After finishing the EZ-2, I started working on two different kits at the same time, a house-of-balsa Two Tee, and the Windsurfer. I wanted another 2m class glider and couldn't decide. The reason for the Two Tee was nostalgic; I built/flew two different Two Tees before (a long time ago, in a galaxy far far away), always loved that T-tail look in flight. The choice for the Windsurfer was curiosity after looking at the plan, it was screaming speeeeed at me.

There are actually two WindSurfers, both represent the high-performance line of Bridi gliders. One is 2m the other is a standard class 100" (although the box says "open class"). The WindSurfers were originally released under Kraft, then later under Bridi Aircraft Designs. It's interesting to note the Kraft release has Kraft radio equipments on the plan, and the Bridi release has Futaba on the plan.

As in the case of the EZ-2, the WindSurfers are out of production (and so is the HOB Two Tee). I've been hunting around the country and get what ever left over Bridi gliders. You can keep an eye out on eBay for these (getting) harder to find kits.

The 2m WindSurfer features (from the box):

Wing Span 78.5"
Wing Area 544 sq in
Estimate Flying wt. 28 oz. (about 7.4 oz/sq ft)
2-Piece plug-in wings
Canopy
Removable Flying Stab

What makes this glider "high-performance"? By looking at the plan, it was immediately apparent that the airfoil is thinner than a typical "floater" (such as the Two Tee). The fully sheeted D-Box design at 2m means a much stronger wing than others in its class; and cap strip for every rib!. The mid-mount full flying stabilizer also means precision control of the elevator without the potential wake turbulence from the airflow after the wing. Like I said, it screamed speeeed at me. Of course any glider with a canopy looks cool. The fact that the wings and the flying stab are removable is just what I want for easy transport.

The kit was very well kitted. all the precision parts are pre-cut, such as wing ribs (not punch-out from die cut) and logically bundled in different groups. Building of this kit went much faster than the EZ2, with the help of (me... lame...) pictures!

Again I decided to do some experimentations, you guessed it, winglets! Deviations from plan:

Lower outer wing panel dihedral (by one inch)
Add winglets!, again, modeled after the DG-600, with larger area and toe out (about 30 degrees). The winglet airfoil is a simple flat "bottom" (the bottom of the winglet is the outside). Of course it's a thinner flat bottom.
Added tube for "inside fuse" antenna placement.
Deciding whether to reinforce the fuse or not

Oops of the day. After I've glued the canopy to the canopy plate, I realized there's no access to the plate if I want to cover/paint the inside of the canopy. I guess the it will end up with the plywood finish.

Here's the latest pics, almost ready to cover:

Note the fully sheeted D-Box and cap strip for every wing rib.

Note the larger toe out angle of the winglets

The wings and the stabilizer are removable for easy transport

Late August '02 Update...

A note on glue (or should I use "adhesive"). The type of glue is very much a personal decision than a performance one. I am not sure there are any comparative study out there comparing the performance of various types of CA (cyanoacrylate), Epoxies, and Aliphatic resins (wood glue). Personally I now use very little CA for my projects. I used to use oodles of CA, thick, medium, thin. Ever since I discovered the quality of good ol' Elmer's Carpenter's wood glue, I haven't used anywhere near the amount of CA as I did before. I still use CA where fast setting, or wood penetration (for strength) is required. Recently I started using Elmer's ProBond, a slightly thicker version of carpenter's wood glue. Excellent stuff. Get yourself some at your Home Depot and try it out.

More experimentation for the cheaper side of things, decided to to try painting the fuse instead of shrink-covering. Things went pretty well considering the el-cheapo spray paint I got (< $2). I believe the trick to painting is not the paint itself, but the primer! Put on the primer, let dry, sand the primer (fine grit), then apply the main coat. Glossy Apple Red for the fuse with some yellow trimming. Then I tried painting on the shrink covering itself. The rudder and wings were covered with Black-Baron metal flake red (cheap and look great!), the stab has econokote yellow (might as well carry on the cheap experiment fully). The yellow trim at the trailing edge is painted on (after a layer of primer of course).

Here are the results. Unfortunately the original canopy mistake now glares at me since I've chosen a dark scheme.

Yup, bare plywood inside the canopy. The yellow trim at the wing's trailing edge is cheap spray-paint!

The wings and the stabilizer are removable for easy transport

notes on construction of winglets (click on image for pdf):