Week Four 4/27/2017

During the fourth week of construction, the shrink wrap, nylon cord, and carbon fiber rods arrived. The goals for this week were to practice using the shrink wrap to properly construct the skin for the glider and to build the outside frame using the carbon fiber rods. While practicing with the shrink wrap, it was noticed that the edges only retracted as it shrunk, therefore it was necessary to crimp the edges using a hot blade. Using a heat gun, the wrap was then shrunk around various items. Markers, pieces of wood, and old kite prototypes were wrapped. In addition, the carbon fiber frame was lashed together using the thin-nylon cord. Superglue was then added to solidify the frame.

Week Three 4/20/2017

Week Three Summary: The original prototype was flimsy, small, and stayed in the air for a very short period of time due to the weight of its construct. A revised, slightly larger model was built today, consisting of straws, string, and thread rather than wooden coffee stirrers. This decision reduced the overall weight by 4 grams, despite the glider having a greater surface area. Ultimately, the new model works better in every way; the frame does not bend and does not require constant maintenance like the original one did and flies straighter. Additionally, there was no guidance string attached. Thus the product resembles a glider more than a kite, and will be thrown between people rather than pulled around a room.

Performance characteristics

Glide ratio: 3
Bend radius: 0
Weight: 15.5g
Glide speed: Variable, more trials needed
Lift: ?
Drag: ?
Dihedral angle: 20 degrees
Wingspan: ?
Dimensions: ?
Surface area: ?
Current total expenditures: $0

Material Concerns: The string at the lab is glossy and frays easily, making it a poor choice of material for any serious design. Thread is sturdier and does not slip as easily, but is still susceptible to breaking under stress. Fishing line and nylon string are being considered as better options, as they provide high strength without adding much weight.

Week Two 4/13/2017

In addition, towards the end of the lab lines were added balance the gliding action of the kite. However, it was decided that the final design will not feature this line, as a glider design will be now constructed instead.

The first prototype of the kite was constructed during week two. It is a scaled down version of the final kite design featuring a wooden frame and plastic skin. The kite measures 45.0 cm wide and 29.5 cm long, which is a little less than half scale. A rounded front and back were constructed using metal wire and straw to keep the plastic skin in a curved shape to allow for smoother air flow. The weight of the kite at this point was 12.0 g.

During preliminary testing, the kite stalled (angled upwards), so weight was added using extra wire and paperclips. This added weight moved the center of mass of the kite towards the front, balancing the lift force so that the kite flies steadily. The final mass for the prototype was  19.1 g.

Week One 4/6/2017

4/6/2017

During the first day of lab, we decided on a Manta ray design for our kite. The kite will feature a rounded front with sides that taper off to the rear. The back of the design will have concave sides that bend inward.

In order to support the kite, rods will be used to keep the fabric of the kite in tension. The fabric of the prototype will be made of plastic bags, but a sturdier, more versatile material will be used in the future. Propositions for the fabric material has included heat shrink, which we could use in a prototype to create tension in the body and eliminate the need for bonding materials (i.e. glue, tape, etc.).
Four proposed materials have been researched so far for the body: carbon fiber, fiberglass, bamboo, and balsa wood. Carbon fiber is the most likely candidate, so rods made of this material were searched for online. The preliminary diameter of the rods will be 1.5 mm, as this was the diameter of the example kite shown in our design class. This diameter will provide a strong ratio of rigidity to flexibility in the kite, so the design remains taught yet malleable.