The Hustler
Your opportunity to build a classic design from the golden age of RC sailplanes.
Call it ‘retro fever’ — designs from 1970s, 1980s and 1990s are amongst the most popular that we publish in the New RC Soaring Digest. We’re delighted to be able to present another in this series with a previously unpublished construction article and drawings from RC soaring legend Don Edberg. These were originally authored in 2002. — Ed.
Recently there has been an increase in popularity of aileron-controlled ‘flat-winged’ sailplanes. These are models with dihedral and ailerons, as opposed to polyhedral models that use rudder control. There are many reasons for this popularity, among them better performance in windy conditions, more maneuverability, higher speed range, and simply that they are more fun to fly. You might consider an aileron model as a sports car compared to a poly model as a commuter car.
This construction article is about how you can quickly and cheaply build a high-performance aileron ship by building a new set of wings to be used with the fuselage of an already existing Airtronics Sagitta 900. The Sagitta appeared in the April 1981 edition of RC Modeler, and a plan set (#831) is available from the plans service. (See Resources below for a current link to Sagitta plans found on Outerzone. — Ed.) Instead of spending $200 or more for a commercial kit such as a Falcon or Saber AND $200 more for wing servos, you can build a new set of wings very inexpensively and need just two aileron servos. The Sagitta 900 fuselage and tail can be used with minimal changes.
The Hustler’s wings are foam-core, with very simple and tough spar construction, and a balsa skin applied with transfer tape. The wings can be built by anyone having the skills to build the Sagitta 900, in a much shorter time period. In fact, if you have a Sagitta 900 kit available, only a few parts need be made — the rest are already in the kit. The airfoil on the prototypes was the Eppler 205.
The Hustler is not a new design. In fact, the first prototype was built in November of 1980 as a test model for the author, who was a member of the 1981 US F3B World Championships team. It was an evolution of the ‘straight-winged’ modification of a Sagitta 900 used to make the 1981 United States F3B team earlier that year. (That wing took a long time to fabricate because of its built-up construction, because it was essentially a fully sheeted Sagitta wing with no polyhedral, and ailerons added.) It was felt that a foam-core version would be faster and easier to build, as well as better aerodynamically. Thus the Hustler was born.
A careful comparison with the Sagitta 900 will show that the wingspan is the same. However, the Hustler features a single-taper wing rather than a constant chord section attached to a tapered tip section. This planform is much easier to build, and does not compromise aerodynamic performance. The wing features a spar construction similar to the Sagitta, yet beefed up for the hard zoom launches that are popular these days. In fact, the Hustler has withstood launches from a long-ago banned 24-volt electric winch!
Hustler only uses a touch of composite materials, and no special skill is needed for their application. The wing is sheeted with 1/16" (1.5mm) balsa sheeting using transfer tape, and may be either covered with plastic film or ‘microglass’, 0.6 oz/yd² (20g/m²) fiberglass. The latter is more work but adds stiffness.
The Hustler, as mentioned earlier, is a ‘full-house’ model, featuring two independent ailerons, elevator, rudder, and spoilers. Flaps are not used to follow the KISS philosophy (“Keep It Simple, Silly”) and to save the cost of two additional servos. Instead, the glide path control is achieved by spoilers activated like the Sagitta’s. Hustler is set up so that the advanced computer radios are unnecessary, which can save additional money for those who would like to try multitask airplanes without buying a computer radio (they were unavailable in 1980 in any case!) The only unusual feature is that there is one servo for each aileron. This makes the linkages trivial — just a short rod from the servo to the aileron control horn — and eliminates control linkages and mechanical hookups with the fuselage. Only two spoiler cables and two aileron connectors need to be hooked up before flying.
You may be asking how well this model flies. After flying the prototype Hustler, I was so enthusiastic about its performance that I built three additional models. In the F3B World Championships that were held in Sacramento during July of 1980, I placed 7th out of some 50 contestants — not bad for an all balsa and foam model constructed in a garage!
After the World Champs, I eventually sold three of the four Hustlers, but I still have one that I regularly fly. This means that the construction has shown its mettle by surviving over 21 years of hard usage! That same model has shown its utility by being competitive in the RCM Trophy Race (now called the International Slope Race), and by placing and winning in many regional northern and southern California slope, thermal, and multitask contests. After its wings were shortened to two meters wingspan, it won the 1982 Two Meter World Cup contest held in Las Vegas.
If you already have a Sagitta 900 and you’d like to try multitask sailplanes without buying a $500 computer radio, a $200 model kit, and $200 more for wing servos, the Hustler should be a worthwhile project to you! Read these simple assembly instructions and you will soon be ready to start your own Hustler!
Construction Procedure
Step 1
Plug one end of the large brass wing joiner tube with a scrap of balsa. Be sure that it is airtight so epoxy won’t leak inside during the next step.
Step 2
Use a coarse file or sandpaper to roughen the outside of the brass tube, and clean off your finger oils with acetone or alcohol. Mix a batch of slow-cure epoxy with microballoons to make a putty-like consistency. Put some in the slot of the joiner block where the tube is located. Put the tube into position, being careful to fill all open areas and get rid of bubbles. Make sure that you have the open end of the brass tube sticking out the correct end of the blocks. Let the epoxy cure before you cut the width of the hardwood block down to 3/8". (If you are working with a Sagitta 900 kit, you will also need to trim off 3/32" from the bottom of the hardwood block that holds the brass tube. Be careful to make a right and a left set.) Both of these operations are best done with a Dremel table saw. (For the Sagitta kit, you will also need to splice the eight spar caps to make four, 48” long pieces. I usually use a long diagonal cut and glue the cut edges together. A 1.5" to 2" long diagonal cut will work fine.)
Step 3
Taper, if necessary, the two pairs of shear webs to accommodate the slight change in thickness along the wing spar. Use a straight pin to make holes in the outer faces of the hardwood block, which will make the glue joint much stronger by increasing the bond area. Also make holes in the mating portions of the plywood shear webs. Don’t get too carried away — just a few holes will increase the glue area.
Separate the parts of the spars into two sets, one for the left spar and one for the right. Use a red felt pen to color the inside face of the hardwood block (that is, the face that the brass tube sticks out of), and the two shear webs. Plan to assemble one spar at a time, one right and one left. The right spar, with the felt pen visible on its root, will look like the one on the plans, while the left will be its mirror image. The longer plywood web is on the front of both spar assemblies.
Now you are ready to assemble the spars. Steps 4 and 5 should be done without interruption.
Step 4
The entire spars will be assembled and allowed to dry, then later joined to the wing. This ensures a strong spar assembly. Mix a batch of epoxy and coat the rear face of the forward plywood shear web, the front face of the aft ply shear web, all faces of the balsa filler block (except half of the rear area). Do not use five-minute epoxy for this step!! Place the hardwood block and the balsa block onto the rear of the forward shear web (be sure that the open end of the tube is towards the outside), and then sandwich them underneath the aft shear web.
Step 5
Coat the spruce spar caps with epoxy 9" out on one wide surface. Put these spar caps into the spaces between the front and rear ply webs. Make sure that the balsa block is pushed hard against the end of the hardwood joiner block, and that everything fits tightly. With epoxy oozing out of everything, it’s a mess, but you’re almost done. Get a bunch of rubber bands and wrap them around all the glued areas. You can also use a bunch of steel ‘paper clamps’ to clamp it all together. Set the spar assemblies aside to cure.
Step 6
While the spar assemblies are curing, you can start preparation of the foam cores. Your reference in this regard is Foam Wings, by J. Alexander, RCM Anthology Library Series. (We have tracked down a current source for this book and noted in Resources, below. — Ed.)
For protection, I like to glue on the leading edge (LE) piece first. You can use either water-based aliphatic resin or User-Friendly Odorless (UFO), the foam-compatible Cyanoacrylate (CA). The former allows more time to get the wood in the proper location. (If you are using a Sagitta kit, you should splice the two short leading edge pieces together with a piece of spruce or ply. You will have to notch the core to fit the splice piece.) Use masking tape to hold the LE in its proper orientation.
Step 7
Now is the time to cut spar notches in the foam core. You will need a 48" straightedge and a Dremel tool with a router attachment and bit. Carefully measure and mark the location of the front and rear of the spars on both the root and tip of the core, then connect with full span marks. Pilot Razor Point pens work well for this application. Then, tape the straightedge into a position so that it will cut right to one of the marks. Use the Dremel to make a slot that is exactly 1/8" (3mm) deep. A scrap of 1/8" balsa is handy for this purpose. The bits are normally not wide enough to make the 3/8" cut in a single pass, so you will have to repeat after moving the straightedge. This will make a mess with little bits of Styrofoam but is easy to clean up with a vacuum cleaner. Check the fit with a piece of 1/8" x 3/8" spruce — it should be snug, not loose or tight. You can make a simple tool to sand the groove with a piece of 120–150 grit sandpaper glued to a piece of 1/8 x 3/8, in turn glued onto a 12” long block.
Step 8
Now repeat this procedure on the bottom of the cores. It is critically important that the locations of the spars coincide, especially at the root. Be very careful in your measuring.
Step 9
Once the spar slots are cut, you will need to remove additional foam where the plywood shear webs and balsa filler block are located. For details, see sections A-A, B-B, and C-C on the plans. This can be done with an X-acto knife with a sharp blade or a hacksaw blade, but be careful either way. You might want to just sand it in, which takes longer but is safer. Final fitting will occur after the spar assemblies have cured.
Step 10
Use the Dremel to cut the tracks for the spoiler tubes. Notice that the right wing and left wing are slightly different, so that the cables will connect to the proper ends of the servo arm. The tubes may be installed with five-minute epoxy or UFO. Leave the portion near the roots loose so that they can easily be fit into the root ribs later. A scrap of balsa supports the end of the tube near the spoiler. Be sure that the tube hole is deep enough at this location (consult with the Sagitta plans for more information). Also check that the tube is more than 1/8" deep where it crosses the aileron wire.
Step 11
You may now cut the aileron wire slots with the Dremel. These can stay just 1/8" deep and the wire will be flush with the bottom of the core. Make two sets of wire by twisting together three insulated conductors of 24 to 26 gauge insulated wire. I recommend black for ground, red for positive, and white or orange for signal. You can glue these wires into position, but they only need to be tack glued, because there are no loads on them.
Step 12
Trial fit each spar assembly in each corresponding wing. If necessary, sand or cut off more foam so that the fit is snug. Check the spar assembly fits snugly within the wing cutout. If the slots are too narrow, the foam may try to expand away from the spar assemblies.
Step 12.5
The original Hustlers had the shear web/spar cap box simply glued together around the joiner tube. If you are concerned about the strength of your joints, you might want to wrap the first two or three inches with carpet thread or better yet, Kevlar® tow or threads. Use CA and be sure to wrap at least the root of the wing, if you do it.
Step 13
Now comes the fun. It is time to glue the spar assembly into the foam core. I used Titebond aliphatic resin on all of my Hustler wings, because it seems to seep in between the beads of the foam core and stick very well. (You may want to try Hot Stuff’s UFO thick CA glue, but I am not sure that there would be enough time and have never tried it.) Apply a generous amount of glue to the front and back of the spar assembly, as well as to the spar cap slots in the core. Gently spread the two caps and slide the spar assembly onto the core. It should move so that the end of the spar is about 1/8" inside of the foam. Use masking tape on both sides to hold the core firmly against the spar at the root. Lay some waxed paper along the inside of the top core bed where the spar is now oozing glue. Place the core/spar inverted into the bed, then place a second piece of waxed paper over the bottom spar. Finally, place the bottom core bed on top of the whole assembly. When you are sure that the cores are properly set in the beds and all parts are properly positioned, place weights on the assembly. I use piles of five or six hardbound books over the entire span of the wing (we’re talking about a library here, 30 or 40 books altogether). I have also used winch batteries. You will want to leave this undisturbed 24–48 hours for the aliphatic resin to dry out totally.
Step 14
After at least 24 hours (with aliphatic resins, less with epoxies), you can open up and look. Now measure the location of the rear alignment pin tubes, and cut a slot to hold them near the root. Glue them in using as little glue as possible.
Step 15
Fit the wing onto your fuselage and joiner rod. If you don’t have a fuselage, you’ll have to get it built before you can continue!! Carefully trim the root of the wing to make it parallel to the fuselage. Drill two 1/8” diameter holes in the fuselage sides positioned to receive and clear the aileron wires and the spoiler tubes. If the brass joiner tube sticks out too far, you may need to file it down. Remember that the root rib is 1/16" (1.5mm) thick, so leave at least that much tube sticking out the spar assembly. It is very important that the brass tube pass through and is bonded to the root rib.
Step 16
The root rib fits onto the root of the wing and is butt-jointed with the sheeting. Remove enough foam so that it fits in well between the wing spar and the fuselage. Glue on the 1/8” ply screw eye mount to take the root screw eye, and drill a matching hole in the foam to clear.
Step 17
Now glue on the root rib. Be sure that both the spoiler tube and the aileron wires are protruding through the holes in the proper location. Use five-minute epoxy and microballoons and fill all the space between the rib, core, and sheeting. Be careful to keep epoxy away from the aileron servo wires.
Step 18
Measure and carefully cut out the aileron servo bay foam, but try to cut in one piece so you can replace it back in the hole so that the sheeting can be put on without caving in. Draw a big X on the top and bottom to indicate where to avoid putting transfer tape, as this piece will be removed after the wing is sheeted.
Step 19
Measure and carefully cut out the spoiler bay with a sharp X-acto knife. Remember to cut the same shape as the spoiler blade. There will be 1/16" sheeting covering the top, so don’t dig down too deep.
Step 20
Take a look at the wing for dents, slots, and other boo-boos. All of these can be filled with the lightweight spackling compound. After the compound dries, sand it gently. Bumps should be avoided because they will show somewhat through the wing surface, but this is the beauty of balsa sheeting — the bumps may be sanded out. Vacuum bagging with fiberglass does not have this luxury.
Step 21
Apply fiberglass tape in a geodetic pattern on the top and bottom surfaces of the wing core, as shown on the plans. Try to avoid the areas of the spoiler bay and the aileron hatch. Be sure that the tape is stuck down well.
Step 22
Join the balsa sheeting pieces for the wing skins. I use thin CA and sand the joints afterwards. If you are careful you can make all four skins out of 10 pieces of 1/16" x 3" x 48" balsa sheeting. I usually try to have the grain parallel to the wing leading edge. Leave the sheeting oversize so that it doesn’t have to be positioned perfectly on the wing.
Step 23
Apply transfer tape to the bottom of the wing. Avoid placing any over the wing spar or the aileron hatch. Put down two layers at the leading edge and the locations just in front of and just behind the spar, as well as at the root and tip of the wing.
Steps 24–30 should be done consecutively, without taking a break, so have about three hours of nonstop time available.
Step 24
Peel off the protective covering from the transfer tape. Squeeze out a bead of your favorite adhesive onto the top of the spar. Now, with the wing core bottom-side up in the bed, carefully position the sheeting just above. It may be worth having a friend to help to be sure the entire area is covered, because once the wood is down, it sticks!
Step 25
Double check to see that the core is in its bed. Now press down the sheeting, starting from the point of first contact outwards. Once contact is made everywhere, use a cloth to rub everything down fairly hard as if you were polishing a car.
Step 26
Turn the wing so its top surface is upwards, and mark the two ends of the spoiler cutout on both the leading edge hardwood and trailing edge (TE) balsa, so that it may be found after the top is sheeted.
Step 27
Bevel the bottom piece of sheeting so that it comes to a sharp edge. Glue the 1/64" plywood trailing edge reinforcement onto the balsa and the top of the foam where it overlaps. Be sure the wing is on a flat surface to prevent warping of the TE.
Step 28
Check for any dents or dings, and fill as necessary. Make a masking tape ‘hinge’ on the trailing edge wood piece bottom, so that the top piece may be just folded over to the correct position. Apply transfer tape to the top, using double layers at the leading edge (just after wood ends), before and after spar cap, root, and foam trailing edge.
Step 29
Peel off the backing of all transfer tape. Apply a bead of glue to the top of the spar and to the plywood trailing edge reinforcement.
Step 30
Now simply fold over the top sheeting, being careful not to pull the masking tape hinge loose. Press down all over, rubbing down with a cloth. Be careful not to crush the sheeting near the spoiler cutout. When all done, place the top bed over the wing, and put as many books or weights on top of the entire surface as possible. An alternate scheme is to use a vacuum bag, but a word to the wise: 1 lb foam crushes at about 4 psi or 8" of mercury, so use very little vacuum or you will ruin the wings. The transfer tape achieves something like 60% of its strength after 24 hours, so let it sit overnight. Repeat with other wing panel.
Step 31
After setting, look at your handiwork! You should trim the leading and trailing edge sheeting, as well as root and tip. You should use a layer of CA to glue the sheeting onto the leading edge hardwood. Glue on the balsa tip.
Step 32
Now carve the tip block to shape, and sand the leading edge to its final shape. Locate the two marks on each end of the spoiler bay, and the rear of the spar cap. Carefully remove the spoiler bay balsa sheet and fit the balsa spoiler blade (trailing edge piece) inside. You may need to take out more foam. If you remove too much, just glue in some balsa sheet spacers. Clear the foam away from the end of the spoiler tube.
Step 33
Lay pieces of 1/16” balsa on the sides and 1/64” ply on the inside of the sheeting of the aileron servo bay. Add your favorite method of holding the servo in place. If you use the Airtronics 94141, you can glue in blocks and simply bolt it into position. With other servos, you can make blocks that the servo slides into, and use a tiny drop of CA to secure into position.
Step 34
Now it’s time for a final sanding before covering. Start with 220 and work your way up to at least 400 grit sandpaper. Try to smooth out all balsa sheeting joints, and the tip blocks. Sand the trailing edge down to the plywood reinforcement, making a knife edge. Fill any dents with putty.
Step 35
This will hurt, but you have to cut up your nice wing now! Cut out the aileron with an X-acto knife or sharp razor saw. Make sure the cuts are in the right position. Glue the balsa pieces onto all exposed foam. Bevel the front of the ailerons to the 20 degree angle, if you do not have the already beveled pieces. This may be done easily with a Dremel saw set to the proper angle, since the ailerons are constant chord.
Step 36
Cover the wing with your favorite covering material. Be sure that it is well stuck down at the leading edge of the ailerons and the trailing edge of the aileron cutout. This is because we will use either tape or covering material as a hinge, and we don’t want the covering to come loose!
Step 37
Now you may attach the aileron to the wing. Use cardboard or paper shims to center the aileron in its cutout. Hold it in its full down position, and carefully tack down the covering material. You can do this at a light heat setting with some materials that will allow you to pull it up if something is wrong. When you are satisfied with the fit and the movement, iron down the entire joined surface. Put some ‘holder’ covering material pieces on the back side of the hinge — one at each end of the aileron, and one at the hinge near the location of the servo pushrod.
Step 38
Cut out the covering over the spoiler bay. Do a final fit on the spoiler before covering it (be sure to allow for the thickness of the covering material). You may now hinge the spoiler similar to the aileron. Next, secure the spoiler horn using CA. Cut out enough foam between the spars for the horn to fit in between. Next, bend up a straight pin as shown on the plans (?) and attach it to the spoiler blade with CA. Fabricate an anchor for the spring and glue it to the top face of the bottom spar cap. Connect the return spring to the two locations. Put the dial cord through the tube and secure to the horn with a toothpick wedged into the hole. If you follow the plans carefully, you will have a spoiler that opens easily but retracts positively.
Step 39
Fit the wing onto the fuselage and use a long 3/32" drill passing through the body to cut a hole into the alignment pin holder wood. Remove the wing and very carefully drill out the hole to 1/8" diameter. Glue the alignment tube into position, using 5 minute epoxy. Slide the wing into position while wet to make sure that the alignment is OK. Repeat with the other wing, being sure that the wings are both at the same incidence.
Step 40
Now terminate the aileron servo wires at the root of the wing. You can either make holes and manually plug them into a ‘y’ connector, or you can make plugs for automatic hookup as shown in the Soaring column, November 1989 RCM (p. 51). I recommend the latter because it will not wear down the wires nearly as much.
Step 41
When you are able, neutralize each aileron servo. Attach an arm to the servos, rotated towards the leading edge about 15–20 degrees. This mechanically provides differential (more up throw than down). If you have a computer radio you can leave the arm perpendicular to the wing surface and set differential mechanically. Make a plywood horn, and glue it to the leading edge of the aileron, or use a commercial plastic horn and embed it within the aileron. Be sure that the horn is mounted securely, or flutter may be a problem. Now make a pushrod by installing a threaded clevis onto one end of a threaded rod, then soldering a clevis onto the other end. You want to make sure that the threaded clevis is located in the middle of its adjustment range when both the servo and aileron are in neutral.
Sagitta Fuselage Modifications
Step 1
You will need to install a ‘y’ connector, or the appropriate wiring if you have built-in connectors. I ended up making clearance holes in the fuselage sides so that the wing connectors could go through and plug in. Later, I came up with the automatic plug-in mentioned earlier.
Step 2
Plug the wings in, plug in the aileron connectors, and see that the ailerons move in the right direction. (Right turn: right aileron goes up, left one goes down). You may want to add rudder coupling for now, but it is best to learn to use the rudder separately. Since ailerons are your primary turning function, I put them on the right-hand stick (Mode 2) and rudder on the left stick.
Step 3
Check to see that both spoilers open at the same time, and close without sticking. Free up any locations that rub.
Step 4 (optional)
We would suggest removing the counterbalance on the rudder, and gluing it onto the fin. Otherwise, at high speeds, there can be a ‘waddle’ that looks bad and slows down the model.
Step 5
That’s all you need to do, except to be sure that the center of gravity is located in the proper location (about 3.8" back from the leading edge). Remember, this new Hustler wing may have a different CG than the older kit wing.
Flying Technique
Pages could be written about flying techniques, but I will try to boil it down into a few important points.
First, you have to recognize that the Hustler is not intended to be a floater. It has high performance but needs to be flown a little differently to achieve it. Be sure that you maintain flying speed at all times, especially thermalling. When thermalling, be sure that the fuselage is more or less level on the horizon, and maintain flying speed. Usually you can use ailerons to bank into a turn, then hold only rudder or some opposite ailerons to keep from spiraling inwards. It is definitely different from flying a poly ship but once you get used to it, you will enjoy it! You will find that the ease of re-centering and changing direction makes an aileron ship a joy to fly.
You will find that the Hustler covers ground very well, and in winds you can easily penetrate upwind to a wave, or thermal downwind and cruise back to the landing area from a great distance. You will need to pay a little more attention to your flying because the aileron-winged ships are not quite as stable.
Launching and landing are similar to the Sagitta, except that for launch you should use rudder for steering rather than ailerons. In fact, in some situations you may discover that giving ailerons creates the opposite of the desired response because the drag of the down aileron overpowers the lift it creates. This is why I suggest that you learn to use the left thumb for rudder only. You can start out with coupled rudder and gradually reduce the amount of coupling until your left thumb is independent.
Landings are a ‘breeze’ because now if one wing drops, you will get an immediate response when you give the correcting aileron control. You will find that you don’t ground loop or flip over nearly as much.
Multitask Flying
As I mentioned at the beginning of this construction article, the Hustler was designed for F3B flying, which these days is also called multitask flying. I believe that you will find the Hustler will compete with the best of the multitask planes of its size, and with larger ones as well.
In distance runs, you will want to fly somewhat faster than you fly for thermalling. You can usually anticipate the near-end turn, and the far-end turn should not be anticipated because you will have to go back and get it if you’re short. The ailerons make pylon turning a snap, because of the instant response. You will find that you can turn in a much shorter distance compared to the poly birds.
For speed, you may want to add ballast. The prototype Hustlers were built with 1/2" model rocket cardboard tube ballast carriers. At the ’81 World Champs I flew with 24 ounces in the wings and 40 in the fuselage, or a total weight of eight pounds! Needless to say, this takes some getting used to and I would suggest adding small weights, like four or eight ounces at a time. For turns, you want to anticipate as much as possible, and as soon as the turn signal is received, pull hard on the elevator if you are already banked over. You will have to practice not ballooning upward as you come out of a turn, because this costs both time and energy.
I hope that you enjoy building and flying the Hustler. You may find, as I did, that polyhedral wings aren’t as much fun any more and that you stick with responsive, high-performance aileron ships!
©2002–present Don Edberg. All rights reserved.
Resources
- Hustler Plan PDF (montaged) — Included in the key image which appears above the title at the beginning of this article. Note this is the product of a low-precision, cut-n-paste workflow which while suitable for simple review purposes, it should not be used where high precision is required.
- Hustler Plan PDF (paged) — The individual PDF pages from which the montage above was cut-n-pasted.
- Hustler Plan CDD — The original ConceptDraw source file used to produce the PDFs above.
- Sagitta 900 Plans by Lee Renaud via Outerzone. — “The Sagittais one of the new breed, which has already proven itself a World Class design in both AMA and F3-B competition. First flown on July 20, 1979…”
- Foam Wings by J. Alexander via RCLibrary in the UK. — “One material that has perhaps done more to revolutionize RC aircraft development and construction in recent years than any other is expanded bead foam…”
Read the next article in this issue, return to the previous article in this issue or go to the table of contents. A PDF version of this article, or the entire issue, is available upon request.
