Introduction: Building "The Frenzy" RC Wing
According to Merriam-Webster Dictionary, a "frenzy" constitutes "great and often wild or uncontrolled activity." That perfectly describes this plane that I have designed. I'm no veteran of RC planes, but this one seems very fast and aerobatic to me. It's also very loud! This could be for a number of reasons - an imbalanced propeller or its position on the plane could be possible causes. I called it "The Frenzy" after my first flight, as it seemed a little berserk at first. I would say this is an intermediate-level airplane, both for the build and its flight characteristics.
Step 1: The Design Explained
Loosely modeled after Flite Test's blunt nose Versa Wing, "The Frenzy" is designed to be constructed of simple pieces that combine to make a performance airplane. I made the plans with nothing but straight lines, except for the winglets. It has a 35 inch wingspan, and full flat-bottomed airfoil that tapers with the wingtips. With my plans, you will not need to print out a PDF or anything like that - you get to draw them yourself.
As always, I'd like to thank Flite Test for all the work they do for the RC community. Check out their videos below.
Standard Versa Wing:
Blunt Nose Conversion:
Step 2: The Parts
This is a list of everything I bought from Hobbyking and used for this plane. "New Purchases" refers to items I bought specifically for this plane, while "Old Purchases" are from my other RC plane Instructable. Check it out here: https://www.instructables.com/id/How-to-Build-Your-...
*Note that two different kind of props are shown in the picture. Both are 7x5, but I decided to actually use an 8x4 prop I already had.
*The push rods I used are .032" music wire I ordered from Jet.com a long time ago with a free shipping offer...I don't think they even sell them anymore. Perhaps you can find some at a hardware store.
*I also used old black servos I already had, but the 9 gram ones I used before should suffice.
XT60 Connectors: https://www.hobbyking.com/hobbyking/store/uh_viewI...
V-tail Mixer: https://www.hobbyking.com/hobbyking/store/uh_viewI...
Transmitter & Receiver: https://www.hobbyking.com/hobbyking/store/uh_viewI...
Battery Charger: https://www.hobbyking.com/hobbyking/store/uh_viewI...
8x4 Propellers: https://www.hobbyking.com/hobbyking/store/uh_viewI...
Control Horns: https://www.hobbyking.com/hobbyking/store/uh_viewI...
Heat Shrink Tube: https://www.hobbyking.com/hobbyking/store/uh_viewI...
Linkage Stoppers: https://www.hobbyking.com/hobbyking/store/uh_viewI...
Servo Extensions: https://www.hobbyking.com/hobbyking/store/uh_viewI...
Motor-ESC Connectors: https://www.hobbyking.com/hobbyking/store/uh_viewI...
Step 3: Building Materials
- 3 sheets of Adams foam board (Dollar Tree)
- Hot glue gun
- Hot glue sticks
- Super glue/thread locker (used on linkage stoppers and motor mounting if desired)
- Utility blades (Harbor Freight - 100 for 4 dollars or so)
- 1.5 mm allen wrench (used for linkage stoppers, motor adjustment, collet adjustment) (Harbor Freight)
- Ruler, pencil, protractor
- Chopstick/thick BBQ skewer
- Very small drill bit and drill
- Black Sharpie marker - Pliers - Paperclips
- Soldering iron & solder (You will need to solder the ESC connections - here is Flite Test's video and another good one on how to do that:
Step 4: Build the Center Section & Hatch
Using the plans I have created, outline the center section and spar on your foam board. I didn't photograph the process fully, but the building techniques are those perfected by Flite Test. I will assume you will have some knowledge of this already, but if you don't, watch their videos - they explain everything better than I could ever dream of.
- When taping both this part and the wing halves, start with the foam cut out but not assembled yet. Start taping on either end and work your way towards the middle - this means the air will flow with the tape and not pull against it. Each stripe is 2 tape-thicknesses. The last piece of tape you put on should be over the double bevel line, which is the leading edge. If you look at my picture, you'll see that I have 5 stripes on either side of a thick black one. Before I put on the last piece of tape, I had 6 stripes on either side of a white un-taped strip. The last piece of tape completes the job.
*Note that I have holes cut in my spar. Flite Test's Versa Wing incorporates this feature, and I copied them just in case I would need them - I didn't. Everything fit into the front hatch except for the ESC, which is mounted on the exterior.
- The spar is glued onto the center section at the reference rectangle on the plans - this means that when the center section is folded, the spar will sit right in front of the last airfoil bend..
- The entire center section is bent and folded like the airfoil model above. Construct it the same way Flite Test does their blunt nose Versa Wing. Make sure you glue the double bevel, score cuts, spar, and trailing edge completely.
You are free to create a hatch as you deem appropriate, but I have developed a way for it that I'm pretty proud of. I cut out a rectangle in the bottom of the center section near the nose with about half an inch gap from the front and sides of the center section. I only scored the side closest to the noseto act as a hinge - I scored the foam board from the side that makes up the inside of the wing. The hatch rests on half of the spar's thickness.
- Notch out two places in the hatch that the skewers will fit through.
- Using the smallest drill bit you can find, drill holes through the diameter of the skewers, using the least amount of pressure possible to avoid cracking them. I rounded the ends with a file, but you can also whittle them with a utility blade or knife. I painted the skewers with superglue, making sure to poke a pin through the hole while the glue is still wet to keep it open - I did this to prevent the skewers from cracking. Puncture two holes in the spar that match up with the notches in the hatch - the skewers will be mounted in those holes.
- Cut the skewers to length so that when inserted into the spar, the drilled holes peep out when the hatch is closed. Glue the skewers in with hot glue.
- I made a couple of washers out of the lid from a plastic food container, but this isn't necessary - it just prevents the foam from denting as bad when the pins are put in place. I colored them black with Sharpie.
- Using paperclips and pliers, I bent some R-clip cotter pins that will click into place in the skewer holes - If you've ever seen hobby-grade RC cars, this is the way the covers are held on.
That was a lot of words, so if you're confused, leave a comment. I'll reply as soon as I can.
Step 5: Build the Wing Halves
Use your ruler and pencil to mark straight lines, and use the protractor to make the angles specified in my plans. I know my plans look really convoluted, but if you only look at the lines you need to mark, it's actually pretty simple.
I have included plans for one wing half (the right one when viewed from above), but to make the left half, simply mirror it.
- Tape the wing halves like the center section: from the outside in. I overlapped the tape a lot on the wing halves because I made the stripes match those of the center section. Because the wings are swept back, the stripes are narrower. Along the edge that meets up with the center section is where you measure from, but because that line is angled to the line the stripes travel, it makes the stripes themselves narrower (I'm sorry you had to go through that explanation). I used a right-angle square to find lines parallel to the leading edge (mark 2 points perpendicular to the leading edge and connect them) - those lines are what the tape follows.
- Along the path of the stripes, my servos are 7 inches from the inside edge of the wing half. That is about 5 1/2 inches horizontally. They are right behind the spar. To mount them, I cut a rectangle in the top surface of the wing and pressed them in with a little glue.
*You may need to cut a slot in your spar for your servo wire to pass through. If I didn't do that, the servo wire would've led to the rear area behind the hatch. Depending on your servo, you might need an extension.
- Test fold your wing halves, and adjust your spars as thick as your airfoil is. The spar on my plans represents the height of the airfoil in a perfect world, but foam thickness and human error causes the actual dimensions to be different.
*If your wing half doesn't line up, don't worry! Trim off anything that sticks out too far. These wings do not have to be perfect.
- Glue the wing halves like you did the center section.
Step 6: Put Them Together
You will probably need to do some trimming to get all three parts to fit together satisfactorily. I tried and tried to get a perfectly flush fit between the pieces, but I never could. I ended up settling with what I had and using hot glue as a gap filler. This seems to work well - it's still strong. Once your gaps are filled, put a piece of tape or two along the seam. The black tape hides it very well, and I'm sure it makes it at least a little stronger. Place the pieces on a flat surface when gluing. This is difficult because the hatch skewers stick out - I just have them overhand the surface I'm working on.
Step 7: Make the Winglets
Measure, mark, and cut out two winglets using my plans, or design your own with the same rough dimensions. I covered the outsides in black tape (keep in mind the mirrored orientation of the two winglets on the two sides of the plane) and the insides in red tape. I wanted a paper surface on the winglet for the hot glue to grab, so I cut out the outline of the wingtip cross section on the tape only - here's how I did it:
Hold the un-taped side of the winglet against the wingtip in the desired position. trace the airfoil curve onto the white surface with a pencil, and darken the line slightly if needed. Then, lightly place the tape onto that surface - the pencil mark should show through the semitransparent tape. Cut the tape along that line very lightly and peel off only the part that the wingtip will cover. Then press the tape on firmly.
- Glue your winglets on, making sure they are perpendicular. You may need to trim the wingtips themselves to even them up a bit (but remember you can use glue as a gap filler). I set my plane on a level surface and held a square against the winglet while the glue cooled.
- Use the wing tape to cover any imperfections or joins and finish the edges with black Sharpie if you want. I still can't decide if I like the white or black edges better, but I can't change it now!
Step 8: The Elevons & V-Tail Mixer
If you have a transmitter with elevon mixing, you will not need a v-tail mixer. Since I have Hobbyking's unprogrammable radio, I bought a v-tail mixer and used it with perfect results.
The v-tail mixer has a side with 2 rows of 3 pins and a side with two servo-wire-like leads opposite. Your servos plug into the pins, and the two wire leads go into the elevator and aileron channels on your reciever. Here's my suggestion: experiment with what plugs into where until you achieve the desired elevon control. You can switch which servo is plugged into which row of pins, and you can swap the v-tail mixer's wires among the elevator and aileron channels.
Here is how you can tell if you have everything set up correctly:
Up on elevator stick: both elevons move up.
Down on elevator stick: both elevons move down.
Left on aileron stick: left elevon moves up, right elevon moves down.
Right on aileron stick: right elevon moves up, left elevon moves down.
- I put my pushrods in the 2nd hole from the center of the control arm, and the throws are perfect, if not a little bit frenzied (hehe). The linkage stopper is mounted in the middle hole of the control horn (the hole had to be drilled out ever so slightly) and a drop of super glue holds the nut in place so the linkage stopper can rotate freely.
*I maxed out my up elevator trim on the first flight, so I adjusted the linkage stoppers to hold the elevons slightly raised when the servos are neutral - this gives me more room to work with on my trims.
- To mount the control horns, I cut a small triangle through the tape and paper on the elevon. I made sure the holes of the control horn were lined up with the hinge of the elevon. I sanded the bottom of the control horn and attached it with a dab of hot glue. It's not the strongest, but if (or when) it rips off, it won't damage the elevon. Just glue it right back on!
- You may need to have a large gap between the tip of the elevon and the winglet, as the angled surface of the elevon will want to hit the inside of the winglet. Trim the elevons until they don't touch the winglet when you give up elevator. The 1/16" gap on my plans is where you can start, and then widen as necessary.
Step 9: Motor & ESC Mounting
I had a motor mount laser cut out of stiff plastic, but you can use wood or maybe even plastic ID card material. My motor mount is a bit small - the motor has very little clearance when mounted. I had to extend the mounting slot all the way to the back, otherwise the top surface of the wing would interfere with the motor.
*I used servo mounting screws to screw the aluminum mounting plate to the plastic motor mount. Any small screw with a wide head should work.
- Tuck the wires through the hole in the side of the motor mount.
- Carefully cut and remove the paper where you will mount the motor. Anywhere the motor mount won't be sticking to, reapply tape to hide the glaring white patch.
*I sanded the bottom of the motor mount so the hot glue will grab better.
- Glue the motor mount on with hot glue and wiggle it around to smear the glue for maximum adhesion.
The ESC is mounted as far forward as is allowed by the length of the wires. Velcro is used for this - stick it right on top of the tape. It is okay if the velcro is not mounted on a flat surface. Mine is right in the middle of an airfoil bend, and the Velcro conforms to it nicely.
-Cut an XT-60-sized hole in the nose. You can fit the ESC wires through that and into the hatch area. Color the edges with black Sharpie to hide it. There's no doubt that the Sharpie makes the hole look better.
*Airflow to both the motor and ESC is maximized by mounting them on the exterior. After a (short) flight with the 8x4 prop, the motor and ESC were negligibly warm, if not the outside temperature.
Step 10: Balance
Make a mark 5 5/8" back from the leading edge of the wing, and that is the center of gravity. Flite Test suggests a slightly nose heavy balance for all of their planes, which means the plane's nose dips down slightly when balanced at the CG mark. From my experiences, the slightly nose heavy balance is too nose heavy - a neutral balance seems to work for me. With a slightly nose heavy plane, I feel like I'm constantly riding the elevator, which I don't like. Use your own discretion with balancing.
*I hold two spread apart fingers in line with the 5 5/8" mark so it's stable in the roll axis but can shift in the pitch axis to tell me its balance.
- I needed a little bit of nose weight in addition to my 2200 mah battery, so I put some keychain thingamajigs in the front. Keep in mind that I have the v-tail mixer crammed in the VERY front underneath the little overhang that the hatch doesn't cover. It balances perfectly! Don't take my word for it however - you always need to do your own experimentation with the balance of your plane.
Step 11: Have a Blast!
Go fly your plane! I had never flown a wing before this one, and my first flight was nerve wracking. I'm so glad it turned out well and flies beautifully.
Launching and landing can be scary, but Flite Test is here to save the day as usual. Here is their video on that subject:
Thanks so much for checking out my Instructable! I've put a lot of hours into designing my own wing, and I'm very proud of it. Feel free to ask questions or comment, and I'll certainly read and reply to them. Happy flying!