Air Rocket Glider – Kit Building Instructions
PDF version: AirRocketGlider62316
Medium grit sandpaper (150-400 grit)
Spring clamp, quick grip style clamp or vise
Pliers, preferably needle nose
Stapler – that will hinge open for tacking
Fine piece of wire, or small paper clip
1. Sand the ends of the tube
Sand the end smooth and perpendicular, using 220 grit paper. Also use the sandpaper to remove any burrs on the inside and outside of the tube at both ends.
Next, prepare the body tube by drawing a line down the length of the tube with a pencil. I like to use the old rocket fin trick – hold the tube into the corner of a door-jamb, and using the jamb as a guide, draw a line the length of the tube.
2. Assemble the Fuselage
Next, locate the Left Fuselage, Right Fuselage, two short Pins and the Nose.
Push the two pins into the indicated holes in one of the fuselage halves. Dry fit the two halves together, making sure to align the pins in their proper holes, and making sure that the two halves seat together completely. If they do not, shorten the pins slightly. Pull the fuselage halves apart again and apply super glue across the flat faces of the fuselage halves. Insert the Nose end in the pocket of the Left Fuselage; note the orientation of the square in the nose, and align the square formed where the front of the fuselage halves meet. Align and clamp the Right Fuselage to the Left, and allow the glue to cure. The rear of the nose will become captured between the two halves. Once dry, if any glue is visible in the large hole, clean out the hole of any glue using a piece of rolled up sandpaper.
3. Assemble the Wing Pivot
Next, you will want to test fit the wing pivot in the hole. Ensure that the wing pivot rotates freely without any binding. Sand down the outer faces of the wing pivot if needed.
4. Assemble the Body Tube to the Fuselage
Glue the assembled fuselage to the body tube using superglue. I like to apply it to the small diameter at the rear of the fuselage in a zig-zag pattern, and install the fuselage into the body tube with a twisting motion. While twisting the fuselage into the body tube, align the split between the fuselage halves with the Vert. Tail pencil line that runs down the tube. Work quickly, you only have a second or two before the glue sets up.
5. Assemble the Fins to the Body Tube
Wrap the sandpaper around the body tube, and carefully sand the curve at the base of each of the three tail fins, to ensure good surface and a matching radius to adhere the tail fins. Wrap a piece of masking tape around the body tube 2” from the open end of the tube. Apply superglue to the inside of the curved base of one of the fins. Carefully align the flat face of the fin with the Vert. Tail pencil line, and also align the leading edge of the fin with the tape edge. Bond the fin in place. Bond the remaining two tail fins in place, spacing the fins as shown below. Note that all three fins are identical, so the base of each fin will wrap around the body tube in the same direction. Remove the tape and pencil lines.
6. Build the Wings
Next, build the wings. Locate the balsa wings. Use the sandpaper to round the leading and trailing edges of the wings. This will help prevent cracks and to improve the aerodynamics. Align the notch in the wing reinforcement (kits now use metal instead of the plastic pictured below), with the notch in the balsa wing. Dry fit the wing reinforcements over the base edges of the wings as shown below. You must leave a channel along the base of the wing for the wing pivot wire to pivot freely. Apply superglue to the areas of the wing covered by the wing reinforcements, and slide them into place.
Now, you need to add the staple that will act as an anchor for the rubber band. The accurate location of this staple is crucial for the proper function of the wings. Notice the staple location marked on the wing template for both the right and left handed wings.
Wing Template PDF: GliderRocketWingStaplingTemplate
Print out and overlay the template on each wing, and open a standard stapler into “tacking” mode. Place the wing on two layers of cardboard, and staple down through the paper template and each wing where indicated. Pull off the paper template, using care not to dislodge the staple. Note they will be mirror images.
Apply superglue over the base of the staple on the underside of each wing. This will harden the balsa, bond the staple in place and reinforce the wing around the staple.
Once the glue has cured, flip the wings over and bend the staple leg nearest to the middle of the wing down flat to the surface. Cover this leg with super glue. Also apply superglue to the base of leg of the staple that is standing straight up. Once the glue has cured, bend a small hook into the staple leg, with the point of the hook aiming towards the angle in the front of the wing.
7. Bend the Pivot Wire
Next, bend the pivot wire. Starting halfway down the length of the 9” wire, using needle nose pliers, form a gentle radius in the wire that matches the outer diameter of the body tube.
The legs of the wire should be parallel to one another, and roughly equal in length – they don’t have to be perfect, they will be trimmed later. As shown in the picture above, grip the wire just below the midline of the tube. Make an approximate 100° bend in each leg of the wire.
Again, the legs of the wire should be parallel after bending.
8. Assemble the moving parts to the Fuselage
Insert the rubber band through the upper tube-like hole in the fuselage. If needed, a short length of small gage wire or a small paperclip can be bent in a “U” and used to thread the rubber band through the tube.
With the wing pivot, installed in the fuselage, align the notches in the wing reinforcements, with the holes in the wing pivot. Ensure the hooks formed by the staples are facing away from the body of the plane. Slide the bent wing pivot wire along the base of each wing, starting at the rear of the wings. It should slide along the base edge of the wings, through the holes in the wing pivot, and out the leading edge of the wing. This may take a couple tries to get it seated, and sometime an assistant helps. Pivot the wings to ensure smooth operation. Mark the excess wire flush to the front edge of the wings, and trim to length.
Stretch the rubber band and hook each end of the band to the formed staple hook on each wing. Careful, as you can easily pull the rubber band out one side of the body. You should now be able to test the folding action of the wings. When released, the wings will hinge forward on the pivot wire, and then rotate on the plastic pivot into gliding position. Ensure they open quickly, evenly and smoothly. If one side opens faster than the other, equalize the tension in the rubber band between the fuselage and the staple on each wing. When you ”pluck” the rubber band like a guitar string, the sound should be the same on each side, indicating equal tension.
Check the angles of the wings in the deployed position. The angle of attack can be adjusted by altering the two 100° bends in the wing pivot wire. The dihedral angle should be correct as supplied, but can be altered by adding tape or thin shims to the top of the wing where the wing pivot contacts the wing reinforcement at the base of each wing. Greater dihedral angle makes the plane more steady, but reduces lift. 3° to 6° usually works well for this plane.
9. Balancing, and Tuning:
Due to varying densities throughout balsa wood, it is important that the ARG be balanced left to right. To do this, simply invert the plane and balance it so it can roll side to side on your fingers. If the plane always rotates so one wing is lower than the other, that lower wing is slightly heavier than the other. Pieces of tape can be added to the tip of the lighter wing tip, until the plane balances evenly. This will help the plane fly straight and true. If you are flying your ARG in a smaller field or park, you can purposely weight one wing tip to intentionally upset this balance. This will cause the ARG to spiral down to the ground, and not drift too far from the launch site.
If the ARG is to be used on a windier day, a second rubber band can be added to increase the opening power of the wings. This will cause the wings to deploy slightly sooner at a lower altitude, but will help prevent the wind from causing the plane to tumble or spin without opening its wings fully. Also, as the rubber band gets old and tired, it should be replaced to ensure proper wing operation. For storage, it is helpful to unhook the rubber band from the wings to prevent it from stretching.
Your Air Rocket Glider is complete!
The ARG launches off of a 3/8” NPT pipe, about 12” long, which is threaded on one end to connect to the launcher valve. There is also a bent piece of wire that holds the wings in the folded position until the ARG is launched. The new Version 2.0 and 2.1 Compressed Air Rocket Launcher kit includes this launch tube, adapter and the piece of wire for the wings.
If you have the older PVC/Sprinkler valve launcher, the existing launch tube is too large. However, through the KickStarter campaign, we supplied one with the ARG order. If you need to make your own, the proper size tube is easily adapted to your existing sprinkler valve. First, you will need a 3/8” NPT pipe that is threaded on one end and is 12” long. This can be sourced from McMaster Carr, part number 9173K412. The easiest way to adapt this smaller launch tube to your existing valve is with a reducer bushing that has a ¾” male NPT thread to a 3/8” Female NPT thread, also available from McMaster Carr, part number 4596K405. The piece of wire that holds the wings folded before launch can be made from an 18” length of wire coat hanger. Bend as shown in the picture below.
Install this wire onto the base of the new 3/8” launch tube as shown below. You will remove your existing ½” PVC launch tube (in white) and replace it with this assembly (in gray).
Here’s the ARG installed, with the wings held back by the bent wire, ready for launch!
If the wings become damaged or broken in use, you can use the wing template in step 6 above to cut some new wings from a sheet of 3/32 balsa available at most hobby shops or craft stores. The wing reinforcements can be made from an aluminum soda can, and the required shape is also shown at full scale on the wing template. The soda can may be cut with regular scissors, just be careful of the sharp edges.