Windsurfer 100 (oz5681)


Windsurfer 100 (oz5681) by Joe Bridi 1982 - plan thumbnail

About this Plan

Windsurfer 100. Radio control sailplane model. Wing area 790 sq in. Plan # 582.

Direct submission to Outerzone.

Update 09/08/2018:Added kit review from MAN August 1984, thanks to RFJ.

Quote: "Field & Bench Review: Windsurfer 100. A Joe Bridi design for silent sensations. By Ralph Boehm.

The Windsurfer 100 is a Standard Class sailplane designed by Joe Bridi and manufactured by Kraft Systems. The basic construction is of the finest quality machine-cut balsa.

Included in the kit are a clear canopy, assorted hardware, full-size plans and a very comprehensive instruction booklet. If there was anything missing, I certainly couldn't find it.

When I opened the box I was amazed at the compact arrangement of the wood. It was obviously an exercise in efficiency! Not a square inch of room was unused. This makes for minimal damage in shipping, as well as giving you the feeling that you are getting what you paid for, which is refreshing.

I selected this particular design for many reasons. I wanted a good flying model, and one that would not take forever to build. Above all, I wanted something that was competitive. I can honestly say that I was more than pleased on all counts.

The Windsurfer 100 is a majestic flying machine. It seems to have eyes for thermals. Like a giant eagle, it seeks out and preys upon lifting air. It is unlike any other sailplane I've ever had. This beautiful bird stalks and tracks and rises in an uncanny fashion, almost as if it had a mind of its own. Perhaps Joe Bridi put something into it that only he knows about. Whatever it is, it's magic. But then, all of Joe Bridi's designs are magic, aren't they?

CONSTRUCTION: The construction of the Windsurfer 100 is as delightful as the performance. It has a well-thought-out design, one in which all the pieces fit like they should. I was never confronted with a head-scratching situation where I didn't know what to do next. The building sequence was conventional and straight-forward, and even the novice builder shouldn't have any problem completing this model.

The fuselage and stab construction, like I've said, are straightforward. The instructions provided are easy to follow. The basic framework of the body contains so few pieces that at first I thought there had to be some pieces missing. Not at all. It is very simple, yet strong. Certainly sailplanes must have integral strength to withstand the abuse of nose-down landings. I have witnessed many such occurrences and have also observed the snapping off of the fuselage toward the tail section. Not so with the Windsurfer 100.

The stab section is designed for a 'plug-in' type of arrangement, which makes it easy to transport, particularly in a small auto. The horizontal stab is of the 'flying' style, and the pivot and actuator setup is well-engineered for minimal slop. The vertical stab is generous in area and very effective. Since the horizontal stab is raised above the base-line of the fuselage, it is free of the vortex coming from the wing. Again, the parts count here was minimal, yet everything was very sturdy once assembled.

The wing design is also a plug-in configuration and is equipped with spoilers. Note: If you use a super powerful winch or launch in extremely windy conditions, I would recommend adding a dihedral brace to the poly-section on the outer panels. The reason I say this is because I cracked mine on a monster winch launch which required repair to the wing. It may not be necessary under normal conditions, but just for added insurance I would suggest that you do it. Construction again is very uncomplicated and goes together so fast you'll be amazed. Make sure that both wing halves are exactly the same size and weight.

I prefer using transparent Super MonoKote on the wing and stab. It is both asthetically pleasing and functional, since the sun shining through makes this bird easily seen from below. I chose Super MonoKote for a number of reasons. It's a very strong film for one, and is extremely manageable. It shrinks evenly and predictably without fuss.

To prepare the model for covering, simply sand the daylights out of the wood until it almost shines. Vacuum off the dust residue and commence covering. A sharp knife and a straightedge are essential tools. When you apply the Super MonoKote, tack it down with your iron at about 6-inch intervals. Pull out any wrinkles and then seal the edges to the wood. Shrink it completely, using your heat gun. Be sure to keep it moving so you don't burn a hole in the material.

Like all sailplanes, the fuselage is narrow, so care must be taken to insure room for your servos, receiver, and battery. There is adequate room, however, and once everything was installed, little ballast was necessary to achieve proper balance. I used a Kraft radio in the Windsurfer 100 and I'm very pleased with the results.

FLYING: It was very windy and bitterly cold on the day of the initial flight test. My determination to see this bird fly, however, could not have been quenched even if a tornado was on the loose!

I set the release hook, hit the winch, and the Windsurfer 100 shot up like a rocket, almost vertical. I realized almost before it happened that this was too much strain on any wing. And then I heard a slight cracking sound. I got off the winch immediately and landed. The outer panel at the dihedral brace had a slight twist in it, and upon examination I found that the dihedral brace had cracked.

I cut a slit in the Super MonoKote, applied some Zap, and it seemed strong enough. I re-rigged it again for launch and this time it went up at a normal angle with no difficulty. Release was right on the money and even with the windy conditions I had little trouble keeping it near. It was a fitting culmination of a fine ship.

Subsequent flights on the Windsurfer 100 have proven to be a joy to behold. The kit is extremely nice to build and the competitive potential of the design is obvious. It is an attractive model that you will be proud to fly and to own. It is just that kind of ship."

Update 01/06/2020: Added kit instructions, thanks to StevenMills.

Quote: "Hi; I have just came across the build instructions for the Windsurfer 100 (oz5681). Please find the pdf attached so others can enjoy also."

Supplementary file notes



Did we get something wrong with these details about this plan (especially the datafile)? That happens sometimes. You can help us fix it.
Add a correction

Windsurfer 100 (oz5681) by Joe Bridi 1982 - model pic

  • (oz5681)
    Windsurfer 100
    by Joe Bridi
    from Kraft Systems (ref:582)
    99in span
    Glider R/C Kit
    clean :)
    formers unchecked
  • Submitted: 24/06/2014
    Filesize: 815KB
    Format: • PDFbitmap
    Credit*: JJ, StevenMills
    Downloads: 3678

Windsurfer 100 (oz5681) by Joe Bridi 1982 - pic 003.jpg
Windsurfer 100 (oz5681) by Joe Bridi 1982 - pic 004.jpg
Windsurfer 100 (oz5681) by Joe Bridi 1982 - pic 005.jpg

Do you have a photo you'd like to submit for this page? Then email

User comments

No comments yet for this plan. Got something to say about this one?
Add a comment



Download File(s):
  • Windsurfer 100 (oz5681)
  • Plan File Filesize: 815KB Filename: Windsurfer_100_oz5681.pdf
  • Supplement Filesize: 391KB Filename: Windsurfer_100_oz5681_instructions.pdf
  • Supplement Filesize: 1474KB Filename: Windsurfer_100_oz5681_review.pdf
  • help with downloads


* Credit field

The Credit field in the Outerzone database is designed to recognise and credit the hard work done in scanning and digitally cleaning these vintage and old timer model aircraft plans to get them into a usable format. Currently, it is also used to credit people simply for uploading the plan to a forum on the internet. Which is not quite the same thing. This will change soon. Probably.


This model plan (like all plans on Outerzone) is supposedly scaled correctly and supposedly will print out nicely at the right size. But that doesn't always happen. If you are about to start building a model plane using this free plan, you are strongly advised to check the scaling very, very carefully before cutting any balsa wood.


Terms of Use

© Outerzone, 2011-2024.

All content is free to download for personal use.

For non-personal use and/or publication: plans, photos, excerpts, links etc may be used, provided that full and clear credit is given to Outerzone with appropriate and specific direction to the original content i.e. a direct hyperlink back to the Outerzone source page.

Unauthorized use and/or duplication of this material without express and written permission from this site's owner is strictly prohibited. If we discover that content is being stolen, we will consider filing a formal DMCA notice.