A successor to the Gnat had been desired since its publication but due to the already small size of the airframe, no further size reductions were feasible. This slow developmental process enabled a "fighter gap" to envelope the Gnat and its larger contemporary, the Super Manx. For several months, no new "drone-fighters" were designed or rolled out. With the success of the later SkyHornet and Super SkyManx paper airplanes, the "Gnat II" project's importance waned. In September 2012, using knowledge gained from designing the SkyHornet and Super SkyManx, I decided to make a new--albeit larger successor to the Gnat with better aerodynamic performance. Equipped with leading edge root extensions (LERX), a high-mounted wing and horizontal stabilizers, the SkyGnat's prototype demonstrated better speed, range and stability compared to its predecessor. With its performance clearly excellent, I decided to make an instructable for the able little airplane.
The SkyGnat is a great choice for use as a fighter-interceptor, stunt and/or research testbed airplane.
Some usages for educators could include studies of:
- Glide ratio
- Hangtime versus other aircraft
- Weight and balance
Step 1: Materials
1 Piece of 8 by 10.5 inch graph paper (4 boxes per inch)
Step 2: Begin Construction
First, begin by folding your your graph paper in half (excluding three boxes on the perforated side). Once the paper has been folded appropriately, make two marks--10 full boxes apart. Use a ruler to make a straight line with the length of 10 boxes directly up 1 row of boxes from the two marks you just made. Then make the rudder and counterweight as shown. Follow the photograph markings. Then, mark out the wing spars and landing gear. From the back, measure 2 boxes forward and make a solid line 2 boxes long. Measure 1 box back from the beginning of this horizontal line and mark out a dotted vertical line. Once all is marked out, cut out the fuselage.
After the fuselage is made, take another sheet of paper that is folded in half along the lines of boxes. Mark out the wing as shown (2 boxes in length by 3 boxes in width, and a swept portion in front of this box of 1 box eliminated every 3 boxes away from the fuselage). In addition, measure 2 boxes along the crease and 2 boxes upwards from one side and the 1 box forward. Then draw a diagonal line connecting this line the other edge of the line along the crease. This will make the horizontal stabilizers. Then cut it out.
Solid lines indicate places to cut. Dotted lines indicate foldlines.
Note: 1 box = 0.25 inches
Step 3: Making the Fuselage
Begin making your airframe's fuselage by cutting it out and folding the counterweight in. Next, cut one of the vertical stabilizers off and fold the landing gear and spars down. Once this is done, fold the vertical stabilizer forward along dotted vertical line and cut along the solid horizontal line as shown. Then unfold. Once this is complete, tape where designated.
Step 4: Applying the Wings and Horizontal Stabilizers; Stapling
Cut out and unfold your wing and flip your airframe inverted. Tape the wing to the fuselage by applying tape to the spars, with the overhang grabbing the wing. Cut off any excess tape. Flip the airframe over and then apply tape to the leading edge of the wing that sits atop the leading edge root extensions. Cut out your horizontal stabilizers and thread them through the fuselage beneath the rudder. Fold them up once through and tape them to the fuselage. Once these surfaces have been mounted, add one staple in the area of the counterweight. This application will complete your SkyGnat.
Step 5: Flight
The SkyGnat is slightly faster and more stable than its predecessor, but those with experience flying small interceptors like the Gnat should be able to transition easily. Launches at moderate to high speed at neutral or negative attitudes will give the aircraft its best possible speed and range performance. Launches can be done at a positive attitude, but launch speed should be faster (range may be reduced). Instability can be cured through proper trimming, and so after only a few test flights the SkyGnat should be able to fly straight very easily. Additional applicable surfaces include slats, flaps, flaperons, elevators, ailerons, spoilers, spoilerons, air brakes and a trimmable rudder. Enjoy!