Week 4 Update

The Wright brothers had their first successful flight three days after their first crash into the sand.  Sadly, this is where our paths diverge from those that happened in December of 1903 at Kitty Hawk, North Carolina.  But we were close!!! We had our first successful flight four days after our first failed flight.  A short video of our first flight is below in Video 1.  And before you wonder for too long, yes; Daniel did get very dizzy testing the kite.  We are sure Daniel will get even dizzier in the future.

Video 1 - Video of First Flight.

This successful flight was one more flight after our unsuccessful one.  In the second flight, the first after last week's post, the kite was set up the same, except that the bridle connected the two lines from the kite.  Just for clarification, the bridle is the part that connects the single line to the kite in multiple locations.  In this case, since we are working on a two-line kite, there are two bridles.  The points where the bridles were connected is in Figure 1 below.  This design was an improvement over the last try, but still did not work.  It was noticed that whenever one of the two lines would be pulled, the other line would go slack.  This was causing the kite to be off-balance and shift on one side of the kite, driving it into the ground.

Figure 1 - Bridle Points for Second Flight

After the first failed flight of the week, the second of the project, we were stuck so we started brainstorming.  In the second flight, the bridle was going slack on one side when turning, but was working fine when not turning.  We predicted that this happened because there were four points of control when both lines were tight, but only three when turning.  On a hunch, we thought that maybe four were needed to have control.  On this hunch, we attached the bridle as drawn in Figure 2.  You will notice in this picture that there are now three lines, each going into the two lines used to fly the kite.  Using this method, at least four lines of the six attached to the kite will be taut as long as the kite is flying.  It worked! This was the design that was used in Video 1!

Figure 2 - Bridle Points for Third Test

Locating the perfect place on the kite for the bridle points was harder than expected, so it took most of our time this week. Because of this, we were not able to get to the point of outfitting the kite as planned.  This may have saved us from puncturing holes in the nylon though. When testing the kite this week, we noticed that the vertical carbon fiber rods were puncturing holes in the plastic.  In order to fix this, we came up with a cap for the ends of the rods. The caps are smoother than the ends of the carbon fiber rods, and will spread out the force of the rod onto a wider area of the material of the kite.  The 3-D model of the piece is below in Figure 3.  These pieces will hopefully result in no more punctures, but we have not tested them yet.  When printing the pieces, though, it took many print attempts to get the tolerances right.  Because of the long wait for the printers in the Innovation Studio, we had to use Daniel's personal printer.  His printer is not as accurate though, so getting the tolerances right was tough and took many tries.  We even managed to snap a piece of carbon fiber when testing an end cap, since the tolerance was too low.  We eventually were able to print the pieces though.  There is a picture of a completed piece in Figure 4.

Figure 3 - 3-D Model of End Cap

Figure 4 - 3-D Printed End Cap

An updated picture of the kite assembly and drawing from last week's posts, including the end caps, are shown in Figure 5 and in the link here respectively.

Figure 5 - Updated Kite Frame Assembly

This week, we were very productive in finding the correct placement for the bridle points.  We were also right about the problems that we predicted we would encounter.  The attachment of the material proved to be difficult since the carbon fiber was putting holes in the material.  Finding the exact placement of the bridle points was also difficult.  Due to the fact that these two issues took so much time to solve, we were not able to outfit the kite in nylon.  Because of this, outfitting the kite in nylon is the main goal for next week.  We also hope to start putting together an outline of our final presentation and report.  This puts us on schedule for building and testing the kite, but very ahead of schedule in the preparation of the presentation and final report.  We do not expect to encounter many problems next week, so there is a very high likelihood of achieving all of our goals for the next week.