Soaring Specialties FUN Slope Glider

The Soaring Specialties One Fun Design (a.k.a. “FUN”) is both a sport sloper and a racer. The FUN is designed on the wing and fuselage rules set forth by the Midwest Slope Challenge's One Design slope race. For those not familiar with it, the One Design class is a slope race formula that sets fairly narrow guidelines for sailplane design and construction. The result is racing airplanes that are generally affordable, easy to fly, and evenly matched.


Wing area:360 sq. in.
Airfoil:S6063 (modified)
Weight:28 oz.
Wing Loading:11.2 oz./sq ft.
Controls:Aileron, elevator
Receiver:Hitec Supreme 8
Ailerons:JR 341
Elevator:JR 341
Battery:4.8v 600mAh NiCad
Available From:Soaring Specialties


The Soaring Specialties One Fun Design (a.k.a. “FUN”) is both a sport sloper and a racer. The FUN is designed on the wing and fuselage rules set forth by the Midwest Slope Challenge's One Design slope race. For those not familiar with it, the One Design class is a slope race formula that sets fairly narrow guidelines for sailplane design and construction. The result is racing airplanes that are generally affordable, easy to fly, and evenly matched.

The FUN meets the One Design rules as a kit with a tough fiberglass fuselage and balsa sheeted foam wing, topped off with very good flying characteristics. The construction of this plane would be very familiar to anyone who has built a sloper in the past ten years or so. Recently, though, molded ARFs and foamie models have made this sort of plane harder to find. Building the Fun involves more work, but the result is a composite plane that's relatively inexpensive.

This review is going to be a longer then usual, because of the longer build process. If you'd like to skip right to the flying part of the review, don't worry, I won't be offended. For everyone else, let's dive right in!

Kit Contents

Let’s start with the most substantial part, the fiberglass fuselage. The unpainted fuselage is sleek, yet quite roomy. There's enough space forward of the wing saddle to easily fit a 600mAh 5-cell battery, a full sized receiver, and a micro servo. It’s also built quite robustly. There was no skimping on the fiberglass with this plane. The fuselage has a fairly thick lay-up, which should make it difficult to damage. A fiberglass canopy provides access to the front of the fuselage.

You can get the FUN with unsheeted wings, or you can get a presheeted version. I opted for the presheeted wings with my kit, as I have some doubts about my ability to sheet the wings without warping them (also, I’m lazy). The two included cores were made from blue foam, and sheeted perfectly with 1/16” balsa.

The kit comes with several precut balsa pieces, including the horizontal stabilizer and parts for the vertical fin. In addition, there are several pieces of beveled trailing edge stock for the elevator and ailerons.

Rounding out the wood parts are the basswood leading edges, and two thin basswood pieces used to reinforce the trailing edge of the wing. Finally, there’s a large light-ply piece, which is intended to reinforce the wing saddle area of the fuselage. The hardware pack is pretty complete. It includes plywood control horns, blind nuts and nylon screws to mount the wing, a strip of fiberglass to reinforce the wing’s center section, and music wire pushrods and clevises for the aileron linkage. About the only thing missing is pushrod hardware for the elevator.


Many who frequent the LiftZone might not be familiar with some of the construction techniques used to build this type of model. These techniques used to be commonplace, but today you are only likely to find them only in composite PSS-type kits. Don’t be scared though, for while the build might be different than what you’re used to, none of it is truly difficult. Anyway, in my opinion, cutting hardwood and sanding balsa is far more satisfying then endlessly applying tape strips to a sticky foam plank (having built a number of foamies, I speak from experience).

The FUN includes a seven-page instruction booklet. The instructions are fairly detailed, and cover each step of construction. However, they do assume that the builder has some familiarity with the construction techniques and tools needed to complete the model. There are three helpful illustrations in the back of the instructions. My only complaint about these is that they are a bit too small.

Wing: The wing is the most involved part of building the FUN. Before I begin, I should mention that I used carpenter’s wood glue to attach most of the wood parts to the wing. I like using wood glue rather than epoxy or CA because it’s strong, easy to sand, and it’s easier to clean up any excess.

The first step (which the instructions indicate is an optional one) is to attach a 1/16” balsa sheet to the trailing edge of the cores. If the builder wants to skip this part the sub trailing edge of the wing will be exposed foam, so it’s a recommend step. If you do want to add the balsa, though, you have to sand the trailing edge of the wing core back by 1/16” to compensate for the thickness of this additional piece. In future kits, I’d suggest to the manufacturer that adding the sheeting should be a mandatory step, and that the wing cores should come with the last 1/16” already removed.

I decided to attach and shape the leading edge pieces next. The leading edges come as two long rectangular basswood sticks. Basswood is a nice choice for this purpose. It’s quite a bit harder and stronger then balsa, yet it isn’t nearly as difficult to sand as spruce. After cutting each piece to length, I glued them to the leading edges of the foam cores, holding them in place with many strips of masking tape.

Shaping the leading edge pieces is about the most time consuming part of building this kit. I started off using an Xacto blade to carve away as much of the excess basswood as possible (the instructions wisely suggest to use a razor planer). Then, using a small t-bar sanding block, I sanded the leading edges flush with the wing sheeting. The final step was to finish-sand the front of the leading edge pieces to a nice round curve, completing the airfoil shape.

Moving back to the trailing edge of the wing: The first step here is to take the two large pieces of balsa trailing edge stock and cut 1/8” from their end edges. With that done, a 1/8” square basswood stick is glued to the aft end of each trailing edge piece. The basswood both stiffens the entire trailing edge piece, and also allows you to sand the edge to a fairly sharp point while still maintaining durability.

The trailing edge stock is actually quite a bit thicker then the sub trailing edge of the wing cores. This brings us to the second most time consuming step in building the FUN: sanding the trailing edge to shape. First, the small root and tip trailing edge pieces must be glued to the rear of the foam cores. Care must be taken on this step to ensure that the pieces are glued on at the same angle. To attach them, I took each core and placed it on the workbench with the sub-trailing edge flat on the work surface. I then glued each piece in place with foam safe medium CA.

Next, I tack glued the ailerons to the sub-trailing edges of the wings. With all the parts of the trailing edge securely in place, I began shaving away as much balsa as I could with an Xacto blade. Once the shape was roughed out, I sanded down the balsa with a t-bar until it conformed to the shape of the rest of the wing. Be prepared to breath lots of balsa dust in this step (or better yet, wear a dust mask). The wing tips could now be attached. I glued the balsa parts to each wing tip with carpenter’s glue, and then sanded the tips to shape.

The instructions suggest glassing the trailing edge and wing tips with light fiberglass. That’s not a bad idea, as the balsa trailing edge ends up being quite thin. In order to strengthen the outer trailing edge pieces and wing tips adequately, I glassed a bit of their undersides.

With the wing now fully shaped, I cut the tacked-on ailerons free and sanded a bevel into their leading edges. The ailerons were somewhat thin and flexible, so like the wing tips, I reinforced them a bit by covering their undersides with light fiberglassNext, it was time to make the servo bays in the wings and install the ply aileron horns. The diagram in the instructions show the horns at the extreme inboard part of the ailerons, with the servos placed very close to the wing root. My preference though, is to drive the ailerons from closer to their centers so they won’t tend to twist as much as. I decided to locate the servo bays about six inches from the wing center. Using a sewing needle, I probed into the wing to figure out the depth and ensure that the servo would fit flush in that location before I cut the bays.

One complication of moving the servos further outboard was that I had to create a much longer channel for the servo wires. My method of creating the channel was somewhat crude, but it did work out. I started out with a long piece of music wire. First, I found the spot on each wing where the wire channel would need to exit the root. Then, I pushed the rod through the foam at the root, until it poked through in the servo bay. With the rod in place, I now had a guide to cut the channel. To accomplish this, I used a brass tube, with small serrations cut on one end. I fed the tube over the music wire rod, and then pushed it into the wing root, rotating it to cut through the foam. Using this method, the brass tube was able to carve out a wiring channel that automatically went right to the servo bay. Once the channels were made, I cut a half circle opening on the bottom of each wing half to allow the servo wires to exit when the wings were joined.

Now that I knew the location of the servos in the wing, I cut slots in the ailerons and installed the ply control horns.

With the individual wing halves complete, it was time to join them. The instructions say to set one wing flat, and prop the other up three inches, giving one and half inches of dihedral per side. That seemed a bit excessive to me, though. I decided to join them with one wing propped up only about an inch rather then three. Since there’s a bevel already cut into the root of one of the wings for the recommended amount of dihedral, I had to do a bit of sanding to get them to meet flush at the reduced angle. Once that was done, I glued the halves together with 30-minute epoxy.

After the wing joint is fully cured, it has to be reinforced with the included heavy fiberglass cloth. I cut the cloth strip in half so I could glass the top and bottom of the center section separately. To begin the process, I lightly sprayed the glass with 3M77 to help keep it tacked down. I then applied the glass to the wing and smoothed it down. Next, I mixed up some Z-Poxy finishing resin and applied it to the cloth. When the cloth was fully wetted out, I took a roll of toilet paper and rolled it across the cloth (in the direction that would not cause the paper to unroll itself). This picks up the excess epoxy from the cloth. Each time the paper was rolled across the surface, I unraveled and removed the epoxy soaked portion from the roll. The process was repeated until the surface was relatively dry.

After the epoxy had fully set, I trimmed any overhanging glass from the leading and trailing edges. When both top and bottom were done, I covered the glass with lightweight balsa filler to fill the weave and blend the edges. Then I sanded it smooth.

As mentioned earlier, the instructions suggest glassing the trailing edges to reinforce them. To do this for the inner portions of the trailing edge, I covered the entire center section, top and bottom, with lightweight glass cloth. When the epoxy was cured, I filled in the edges with balsa filler and sanded it smooth. Now it was time to drill the wing mounting holes. The first step is to drill out two ½” holes, which go through the upper wing skin and the foam core, but not through the lower wing skin. These holes are then filled with a mix of micro balloons and epoxy. Once this is done, the instructions say to drill the final 3/16” bolt hole fully through the filler and out through the bottom of the wing. I skipped this part until I was ready to actually mount the wing on the fuselage, though.

At this point, I took a detour from the wing construction and set about installing the wing mounting hardware in the fuselage. Before doing any work on it, I washed the fuselage with soap and water, and scrubbed it down to remove any trace of mold release.

The instructions say to use the leftover basswood from the leading edges to create the fore and aft wing mounting blocks. I opted instead to cut some of my own blocks using some spare aircraft ply.

Although the fuselage seems very strong, the FUN comes with some further reinforcement in the form of a large light-ply saddle brace. This brace fits underneath the wing saddle, and reinforces the upper part of the fuselage, especially near the wing mount points where most planes tend to get cracks, or break outright (especially when carrying a lot of ballast).

Rather then gluing the wing mounting blocks to the bottom of the brace before installing it, I opted to install the brace into the fuselage first. I found that the bottom of the upper fuselage is quite uneven because of the seam between the two fuselage halves. Consequently, I ended up sanding the brace quite a bit to get it to fit. I also enlarged the hole in the brace beyond the recommended size to make it easier to install and allow easier access to the inside of the fuselage ballast area later.

Once I was satisfied with the fit of the brace, I applied some epoxy, and clamped it in place at the front and back. After the brace was glued in I filled the gap between the brace and the top of the wing saddle with epoxy and micro balloons, as it doesn’t fit completely flush. I next installed the front and rear wing mounting blocks under the brace.

It was now time to mount the wing. The first step was to ensure proper wing alignment. I placed the wing on the fuselage, and then carefully measured from the trailing edge at each wing tip to the end of the tail boom. When both measurements were equal, I knew the wing was aligned. I tack glued the wing in place on the fuselage with thick CA, then drilled a small diameter hole at each mounting point, straight through the wing and into the ply blocks in the fuselage. This properly located the holes in both parts. I popped the wing from the fuselage and enlarged the holes in the wing to fit the nylon bolts. I then enlarged the holes in the fuselage mounting blocks so that the blind nuts would fit in them. The blind nuts were then installed on the bottom of the mounting blocks, and pressed in place with clamps. Now I could finally bolt the wing to the fuselage. I noticed one slight problem…when viewed head-on the wing was tilted a bit to one side. I assume this had something to do with my readjustment of the dihedral angle. No problem, though: I straightened it out by installing a 1/32” shim on edge of the wing saddle to push the low wing higher. Not a pretty solution, but the next step would solve that.

Although the wing actually fits on the saddle pretty well, the instructions call for filling the wing saddle area to get a perfect fit between the wing and fuselage (it also takes care of the issue of my ugly wing shim). The process works as follows: First tape is applied to the bottom of the center section of the wing. When doing this sort of thing, I also like to apply some sort of release agent to the tape (like wax or Vaseline, etc). Next the sides of the fuselage are masked off just below the wing saddle. Now the fun part: a liberal amount of epoxy, thickened with micro balloons, or similar, is slathered all over the wing saddle area.

The wing is then mounted on the fuselage and bolted in place, and the excess epoxy is squeezed out the sides. When cured, the tape on the wing allows it to be easily popped off the fuselage. The epoxy/filler is then sanded flush with the sides of the fuselage, giving a perfectly fitting wing saddle (and hiding my wing shim in the process).

With the above out of the way, I turned my attention fully back to the wing. I decided to install the servos before covering it. The aileron servos I’d be using were JR 341’s, which were salvaged from my dearly departed Opus V. I fished the servo wires through the wiring channels and soldered on the connectors. Next, I installed the control horns on the servos and set up the servo linkages using the supplied pushrods and clevises. After verifying that everything was properly aligned, I wrapped the servos in masking tape, and glued them in place in their bays with silicon RTV sealant.

The wing construction was done. Before covering the wing, I gave it the once-over with balsa filler to fix any imperfections, dents, or dings. I then covered the wing with a combination of pearl blue Ultracote and white Monokote. To finish it off, I taped on some small plastic servo covers (courtesy of Dieter at Shredair). Finally, I taped the ailerons on with Mylar hinge tape from Soaring Specialties.

The parts I worked on next were the horizontal stabilizer and the elevator. The stabilizer is pre-cut to shape, so all I really had to do to it was round off the leading edge. The elevator is a piece of trailing edge stock just like that used for the ailerons. It must first be cut to a width that fits the stabilizer. It’s also a lot thicker then the stabilizer, so like the trailing edge stock used on the wing, it must be sanded down quite a bit.

I sanded a bevel into the elevator’s leading edge, and then cut the slot for the elevator horn. The ply elevator horn is quite bit longer then it needs to be, and would hang well below the end of the fuselage if not trimmed. So, I sanded the horn to an appropriate height, and drilled a new hole for the clevis. Then I glued the horn in place.

When the horizontal stabilizer was finished and sanded smooth, I covered it with Monokote and Ultracote. I left gaps in the center section where the part would need to attach to the fuselage, and where the vertical fin would be attached. Finally, I covered the elevator.

Now let’s return to the fuselage (again). My next task was to install the elevator servo, but first I’d need to make a servo tray. I trial fit my battery, a 4.8v 600mAh battery pack, and my receiver (a Hitec Supreme 8), in the front of the fuselage to determine where the servo should be placed. Using some scrap light-ply, I made a tray that would hold both the servo and the switch, and glued it in place in the fuselage with Elmer’s Polyurethane glue (which I’ve never used before…I hope it holds).

The kit does not include an elevator pushrod, so I chose the materials myself. I used a generic plastic pushrod housing along with a Sullivan cable for the pushrod itself. I soldered a threaded coupler to one end of the cable so that a clevis could be attached.

Before installing the pushrod, I tack glued the horizontal stabilizer to the tail to make sure I was gluing the housing in the right place. In the forward fuselage, the pushrod was glued to the left side, just under the wing mounting blocks. As the pushrod traveled back, it transitioned from the side of the fuselage to the floor of the tail boom. To glue this part in, I held the pushrod housing in place, using the cable to position the aft end of it. I then took thin CA and dribbled it onto the pushrod housing at the wing saddle area, allowing it to trickle down (making sure to keep the end of the housing raised a bit so no CA got inside). A couple shots of accelerator fixed the housing firmly to the fuselage. The instructions mention that the stabilizer should overhang the end of the fuselage by about ½”, to prevent any problems with adjusting the clevis at the elevator end. I’ve never had an issue with this before, so I left the tail boom as it came, ending flush with the back edge of the stabilizer. The vertical stabilizer comes as two pre-cut pieces that need to be glued together. Once I had done that, I sanded the joint smooth and rounded the leading and trailing edges. With the horizontal stabilizer still tack glued to the fuselage, I checked the vertical’s fit. I found that quite a bit of trimming was needed to get the fin to fit flush with both the top of the fuselage and the top of the horizontal.

The instructions say to install some triangular doublers at the base of the fin, where it will contact the horizontal stabilizer. These doublers are actually not included in the kit, though, so I went to the hobby shop and got some ¼” balsa triangular stock for this purpose. I glued the doublers on and then sanded them round at the front and back.

My focus again returned to the fuselage, this time, with the canopy. One thing that's always an issue on nearly every slope kit I've built is the interface between the fuselage, wing and canopy. Invariably there's a gap here, and it's hard to trim the canopy in a way that gives a perfect seal between the parts (for me, at least). My solution here is similar to what was done on the wing saddle. I masked off the leading edge of the wing's center with packing tape and mounted it on the fuselage. Next, I put tape on the bottom/inner surface of the canopy. I mixed up some epoxy and micros and applied it to the fuselage, in the area between the leading edge of the wing saddle and the rear opening of the cockpit. I then squished the canopy in place and taped it down. When the epoxy was cured, I sanded it down to match the canopy and fuselage. When I popped the canopy off I was left with a perfect seal in this area.

When the above was done, I did the same thing around sides and front of the area where the canopy contacts the fuselage, creating a nice seal all the way around the seam. Note: I did only one side at a time, to lessen the chance that I would accidentally glue the canopy on permanently!

I created a forward hold-down on the canopy by gluing a long piece of wire underneath it, which extended out about 1/4". The wire slid underneath the top of the nose to hold the front of the canopy on. To ensure a perfect fit, I put a glob of epoxy/microballons underneath the nose, then put the canopy on and taped it in place. When the glue had set, I pulled the canopy off, and was left with a perfectly placed hole for the hold-down wire to go into. I held off making the rear canopy hold down because I wasn't as yet sure what I wanted to use for it.

Once the canopy was done, it was time for my all-time least favorite step: painting the fuselage. I don't have great luck with painting, probably because I'm not very patient. Basically I try to get a relatively smooth, relatively shiny paint job, but by no means a perfect one. I started by sanding the seams on the fuselage smooth. Then I filled any large voids in the glass with epoxy/filler, and sanded them smooth. I followed this step up with Bob Violet Pinhole Filler. This product is a paste that is rubbed on with a paper towel, allowed to dry, and then rubbed off again. It fills the bulk of the tiny pinholes that unpainted glass fuselages usually have. Before I put any paint on, I had to mask off the areas where the stabilizers would be glued to the fuselage. I used masking tape on the horizontal stabilizer saddle, and a piece of thin striping tape for the area forward of the saddle, where the fin sits.With everything finally ready, I applied a coat of Krylon gray primer. Any remaining voids or holes that were left after spraying the primer got filled with Squadron putty. The putty comes in a tube, and is sort of like a Bondo that's made for plastic scale models. It fills small holes and is easy to sand. After sanding, I applied a final primer coat. When I had sanded the primer smooth, I put on the color coat, using Krylon gloss white. Krylon isn't the best or most durable paint, I'll admit, but it dries very quickly, and doesn't run (a big plus for us impatient types). I finished the canopy in a similar manner, using gloss black Krylon.

After the paint had dried, it was finally time for mounting the tail feathers. First, I test fit the horizontal stabilizer onto it's saddle, using a clamp to hold it in place. Using an incidence gauge on the wing and a torpedo level on the stabilizer, I confirmed that the decalage was about 1 degree positive. To check that the alignment was correct, I used a long ruler to measure the distance between each wing tip and the tip of each side of the stabilizer. Finally, I checked that the wing and the stabilizer were level with each other by sighting the alignment from behind the plane. When I was happy with everything, I marked the position of the stabilizer and removed it. I applied 30-minute epoxy to both the stabilizer and the saddle area of the fuselage and clamped the stabilizer in place again, aligning it with the marks I had made. I confirmed that all the alignments were correct while the epoxy was setting up (phew...that's a lot of aligning). When the horizontal was securely in place, I used Mylar hinge tape to attach the elevator.I next took the vertical fin and checked its alignment before attaching it. I used a triangle to make sure that the fin was sitting perpendicular to the horizontal stabilizer. I then applied 5-minute epoxy to all the contact areas of the fuselage, horizontal stabilizer, and the bottom of the vertical fin, and then set the fin in place.

The final task in construction was the rear canopy hold-down. After much procrastinating, I decided on a simple yet very effective hold-down method that I had seen a friend use several years ago. This involves using a sheet metal or wood screw, and a small piece of rubber tubing. You can see how it works below...

Radio gear and setup:

As mentioned earlier, I used JR 341 micro servos for all control surfaces. A Hitec Supreme 8 full sized receiver was used, along with a 4-cell 600mAh battery. The instructions actually recommend a 5-cell battery, with the fifth cell sticking up into the nose. This is a good idea, but I just happened to have an extra 4.8v pack, so I decided to use that instead. The instructions also show the servo mounted ahead of the receiver, rather then behind it. I must admit that I missed this part until after I had installed the servo tray.

The plane needed about one ounce of lead in the nose to balance on the recommended CG. Final flying was 28 ounces. That gives a wing loading of about 11 ounces per square foot, which is pretty typical for a sloper. The minimum weight for planes entering the One Design Class race is actually 25 ounces. Any less then that and you have to add ballast to bring your plane up to the minimum. I would hardly call my airplane heavy, but I could have probably saved an ounce or two if I hadn't been so generous with the micro balloon filler, and so liberal with the paint, as I put on a very heavy coat. I also could have mounted the servo tray further forward as the instructions indicated, and used a lighter receiver.


Let's Fly!

As always seems to be the case, the first flight took place on a day with light, or at best moderate lift. Ah well, we can’t be too choosey about conditions in Southern California’s autumn. After a preflight and range check, the FUN was given a good toss off the slope. The CG and trim both seemed good. There wasn’t a whole lot I could do given the conditions, but the plane seemed easy to both maneuver and keep aloft in the light air. There was no issue with the reduced dihedral angle I used. The stability was typical for a plane of this size.

I had a bit of camber programmed to activate with a switch on my radio, which seemed appropriate to use in the light lift. The camber did not really have much noticeable effect, though. That’s okay, because although the One Design slope racing rules do allow for camber changing, they tend to discourage this type of electronic gadgetry in favor simplicity.

The lift increased a bit more later in the day, allowing me to get a somewhat better assessment of the FUN. Roll response was good, though the roll rate itself wasn't too high, possibly owing to the somewhat small-chord ailerons. I could also have probably added more of a bevel to the ailerons to increase their available throw, giving a faster roll rate. The airplane will do smooth axial rolls when a little bit of down elevator is applied when inverted. I tried a few loops too, which turned out very well. There’s no tendency to snap out at the top of the loop, or drift off to either side.

Eventually, I removed a bit of weight from the nose, moving the CG back about 1/8” from the start position (which is 4” ahead of the trailing edge). The plane still did not seem twitchy or unstable, so I moved the CG further back by another 1/8".

I tried a few stall tests next. From wings level, the FUN stalled straight ahead, with no tendency to drop a wing tip. The stalls were all fairly gentle, and the plane recovered quickly.

With the requisite aerobatics out of the way, I went on to testing the speed and turning performance of the FUN. This is a racer after all!Well, okay, it’s a one design entry-level racer, so I didn’t expect blistering speed. Still, it’s no slowpoke. Compared with the 60” molded plane I was flying with at the time, I’d say it was pretty respectable. The airplane turns very well too, and doesn’t seem to lose too much energy. I was only able to get it to tip stall in a turn by pulling super hard on the elevator at low speeds (in other words, doing something silly).

Some of the local guys were beginning to dynamic soar as conditions improved, and I just couldn’t resist the DS call. Of course, the FUN isn’t made for dynamic soaring: the wing doesn’t even have a spar or any other internal reinforcement. Still, the DS conditions were light and fairly smooth, and curiosity got the best of me. The FUN actually handled surprisingly well. It probably never got going faster then 60mph, but it seemed to retain energy well, despite having an airfoil that’s not exactly optimized for this task. If you’re willing to risk a non-foamie to learn, the FUN could make a reasonably good DS trainer. You just have to remember that it’s not designed for super fast DS speeds and high g-loads.

I set up the FUN with spoilerons for speed control on landings. Spoilerons have different effects on different planes, causing the plane to both slow down and lose altitude in varying degrees. With the FUN, you get a bit more of the later then you do the former. Popping full spoileron will cause the plane to lose altitude very quickly indeed. Therefore, I found that it was best to apply the spoilerons early in the approach, using the elevator to hold the nose up and slow down. Then I could start retracting the spoilerons and float in to a nice soft landing.

Flying with Ballast:Finally the autumn doldrums abated and there came a day when I was able to fly the FUN in good lift. The Santa Ana winds had arrived. This was a mixed blessing, because along with the winds, our area was struck with at least three major brush fires. When I arrived at the hill, the air was choked with smoke and ash, due to a fire about 10 miles away. As you might expect, though, the wind was good, and I decided it would be a good time to see how the FUN would fly with a little ballast.

Earlier in the week I had installed my dead simple ballast system...a small hole through the bottom of the fuselage at the CG. I had several different lead weights with me at the hill, but I opted for the largest one: a block that weighs a bit over 1/2 pound. This put the flying weight of the plane at about 37 ounces, which is actually over the maximum allowed One Design race weight of 35 ounces. I launched the FUN and it quickly gained altitude. With the ballast in place, the plane had a wing loading of about 14 ounces per square foot. It could have probably used more, but since the lift was cycling somewhat, I decided not to chance it. In the good conditions, the plane was easy to handle, and obviously fast (Again, I can't say it is as blazing fast a molded plane, as the speed is somewhat limited by the 9.5% thickness airfoil that the One Design class mandates). I had loads of fun flying inverted and doing aerobatics. Next I tried a few "half pipes," which resulted in some good vertical climbs. Finally I got down low so I could carve pylon turns back and forth across the slope. I didn't have any other one design type airplanes to fly along with, so its hard to make comparisons, but I think the FUN should be able to handle itself quite nicely in a race situation.


One of the most common questions I get at the slope is “what kind of plane I should get next?”Usually that question is being asked by a foamie pilot who's looking for his first “crunchie” sailplane. A few years ago, the answer to that question would have been easy: You’d start with a 2-meter span polyhedral floater with rudder and elevator control and a built-up balsa wing. Then you might move up to your first aileron slope ship…still made of balsa, but with a sheeted foam wing and a bit more performance then your trainer. Perhaps it would be a Son of Savage, Sig Ninja, or a wood-winged C.R. Renegade. You might move up to a plane that mixed sheeted wings with a fiberglass fuselage. These planes offered sleek looks and good performance in a relatively inexpensive package. Planes with names like Dragonfly, Sparrow, and Quicksilver ruled the skies over many slopes in those days.Things are not so straightforward these days. There are any number of EPP foam slopers to chose from that offer good performance, low cost, and relative indestructibity. On the other end of the spectrum are a large number of molded ARFs that offer screaming speed, crisp aerobatics, and sleek looks. These qualities are unfortunately combined with fragility and a big ding in your wallet. The problem is this:there is very little in between!With the exception of a few PSS warbirds, the relatively inexpensive, glass fuselage/foam-wing sloper kits seem to have almost disappeared. The One Fun offers a package that falls nicely in-between the foamies and the moldies. It's a relatively inexpensive plane with good performance and tough construction that should hold up well even on rough Southern California slopes. I've seen many a foamie pilot fall into the trap of never quite being able to land smoothly. Planes like the FUN can give a pilot the experience of flying and landing a conventional-design composite plane without as many of the worries that come with a fragile fully molded glider. Aside from being a One Design racer or a transition plane, the FUN would make a good aileron trailer or just an all-around (dare I say "fun"?) sport plane.

Thanks to Bill and Alex for their help with the in-flight pictures.

Thread Tools
There are no posts

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Foam flying wing slope glider plans apolo1 Power Systems 16 Jan 13, 2009 06:54 PM
New LiftZone Review: Soaring Specialties FUN bjaffee Sailplane Talk 3 Nov 27, 2003 03:01 PM
New Review on LiftZone: Soaring Specialties "FUN" bjaffee Slope 0 Nov 25, 2003 02:52 PM
GWS Slope Glider J-3 and Stick version GWS4CEO Slope 13 Apr 22, 2002 07:27 PM
BD-5 Slope Glider...NIB gliderdude Aircraft - Electric - Airplanes (FS/W) 5 Jan 15, 2002 07:03 PM