Wooden airplanes never cease to amaze me. The construction of the wings especially always strike me as a work of art. This instructable will show you how to make a balsa wood aircraft using some methods that are used for making larger planes as well.
Who in their right mind would want to spend many hours of hard labor to create an airplane when they could just stuff an egg in a cotton ball bag and drop it from 5 meters with the same results? A creative mind would-and since you're on instructables.com, I would expect that you are a creative mind.
This gliding egg lander is built like any other airplane made of wood- it has spars and ribs and monokote as the "skin" of the aircraft. This version is complete with LED lights and Elevators. With a calculated wing loading of 11.86 oz/sqft^2, the project was a go.
The first step (pre-step) is to figure out what the heck you're going to build. Look on one of the images in step one with the blue-print. That was the basic aircraft design that was followed throughout this project.
Basically the wing had a 2 degree angle of attack which is pretty standard for gliders and it also had a 7.4 degree dihedral angle for stability while in flight.
All the other information is included on the photographs: Dimensions of the wings, length, width, height, etc.
The final product had a single boom vs the twin boom design seen in the drawing.
And if you are not making this for an egg drop project, the plane can be made into a real one. You'll have to refine how the fuselage is made, but other than that, the wing should be perfect.
Step 1: Materials
Okay, so before you actually start, lets look at the difficulty level and the time you'll need.
Difficulty Level: 4-5 out of 10 with 10 being the most challenging project ever
Time: 18-25 Hours depending on your level of experience.
Balsa Wood (I had a lot of scrap pieces from the solar plane project) Make sure the you have sheets with a variety of thicknesses. Consult model airplanes to figure out what thicknesses you may want. Make sure to buy pieces for the spars too. Thicker Spar goes in the front, the thinner one in the back.
Basswood: For the tail boom.
CA Glue & Accelerator
Monokote (For covering the wings)
5mm LEDS or other sized LEDS (depending on where you want lights to be located)
CR2032 Battery Holder (optional)
Regular Super Glue
Optional: Egg with Ziploc Bag
Photo Editing Software
Nail Polish Remover (because of the glue)
Super Glue Gun
Step 2: Wing Construction I
The first part to wing construction is going online and finding a rib design that you like. I used the "standard" Clark Y Aerofoil Profile. Find one online and print out the rib cutout. It is optional that you make thinner ribs as the wing progresses outward. For this project, i was constrained on the dimensions of my plane, hence the large, boxy wing to get the most surface area.
The wing was constructed in two halves, the right and left, the joined at the center with some more wood and glue.
Once all the ribs are printed out, trace them to fit onto your balsa wood sheet. If you're following my blueprint, there should be 10 ribs. (plus some longer ribs for the center - I had 3 more extra ribs)
Take these ribs and cut out the little squares for where the spars will go. I did a rough estimate and cut them all at the same spot. (Figure out how large the spars are first before you cut)
This part is optional: to add LED lights to the starboard and port side of the wings, drill small holes. (5mm where the LEDs go and much smaller ones where the wires will go)
Step 3: Wing Construction II
Next, use your photo editing software to create 5 evenly spaced segments so you can have a layout for your ribs.
String both of the spars, front and rear, through the ribs, and once in place, begin gluing them down with the CA glue. After applying a dab of glue, use the accelerator to instantly "freeze" the parts in place. The reaction will make the wood get hot, so make sure not to burn your hands. Then, cut out the trailing edge and leading edge from more balsa wood. (again, apologies for not knowing the exact size of everything, most of the wood I had on hand were scrap parts) After completing both sets of wings, insert the LEDs that have been soldered along with the wires (positive = red, ground = black), though the pre-cut holes for the wires.
After that, take your 3 longer ribs that you cut and depending on your width of the fuselage, match it to the same dimension. Then, also add spars. The trailing and leading edge are optional if you follow this build.
Then, connect both sides of the wing to the center piece and now the skeleton of the wing is complete.
Step 4: Wing Construction III
Now it's time to print out the graphics that will go on your wing. Figure out the size, use your photo editing software to size it and print it out. Cut out those graphics and glue them with stick glue onto the wing.
Monokote is that plasticy shrink wrapping material that is used as the skin for many model aircraft. It's relatively easy to use. Just figure out the sizes, cut it out, and apply it on.There are a lot of youtube videos on how to go about doing this.
To apply on the monokote, cut out a bit extra than how much you actually need. Then, match it to the area that you are going to monokote and iron on the edges, as tightly as possible. After getting all the edges ironed, the monokote will look flimsy in the center. This is where you use the heat gun. The heat gun will shrink the monkote against the wood, creating a tight surface, kind of like a drum. Be sure not to heat up the same area too long or the monkote will melt.
After applying the monokote, take the wires from both halves of the now connected wing and solder together the positive and negative sides and attach it to an xt-60 connector if you have one available. If not, then fashion out your own connectors with straws and wires.
Now your wing should be complete. Stand back and admire what 15 hours of work have gotten you to...(possibly 15 hours if you're doing this for the first time)
Step 5: Fuselage Construction
For the Fuselage, I used two really thick pieces of balsa wood to sandwich the center supports. To make the fuselage, go onto your photo editing software and draw out what you would like for it to look like. If you want the two degree angle of attack, then make the top of the fuselage dip down by two degrees,
Print out the these side fuselage pieces and trace/cut them out from the balsa wood. Next, knowing how thick the fuselage is going to be, cut out the support pieces and CA glue them to the fuselage side pieces. The grain (direction) of the wood matters. Make sure that the grains are horizontal to provide structural integrity.
In the process, if you know where you want the LEDs to go, wire them in to those support pieces. I was not able to wire everything to one battery---I'm guessing the LEDS weren't getting enough amps.
Next, attach the boom to the fuselage. Insert the basswood through the rear of the fuselage through the supports to create a strong structure. Attach on the horizontal stabilizer which is a piece of balsa wood, then glue on the vertical stabilizer. Make sure to reinforce them with extra pieces of balsa wood. Also make sure to have working elevators on the horizontal stabilizer.
Drill holes for wiring and LEDs if you so please. (look at images)
For the landing gear, I had skids that were suspended with rubber bands to cushion the landing. It's not the best way to create the most shock absorbency, but it works.
Step 6: Wing to Fuselage
Attaching the wing to the fuselage is pretty easy. Make two posts on the supports of the fuselage where rubber bands can be attached to. (see images)
Once you have the posts down, create an area in the front portion of the plane for your egg to sit in. (mine was pretty makeshift-with rubber bands and cotton balls.
Then attach on the final decals and balance out the plane. Add little weights (paperclips, pennies, quarters) and now you're ready to launch your glider.
If you had LEDs, turn all of them on, stand back, and admire the beauty.
Step 7: Final Thoughts
Now if you actually completed the project, the first question I asked about why anyone in their right mind would create such a thing, would make sense. You would do this for its sheer awesomeness.
Once you're done with the egg portion, just toss that and attach a real motor to the plane-and possibly change out the fuselage. And...you might want to make a more complex wing design that what is shown here.