Three years ago,
Columbia University's Solar Splash team introduced a novel and innovative design
to the Solar Splash competition by entering a hovercraft. The boat is a
conventional displacement catamaran during the endurance race but switches to
hover mode for the sprint race. The 2001 Columbia University team
encountered many obstacles when racing the hovercraft. These issues included
excessive weight, a weak transmission, and lack of testing. In 2002, the
hovercraft was completely redesigned for better performance. Although the
second generation hovercraft was dramatically better than our previous one,
there were still many problems faced by our team.
The primary focus
of our team this year has been to build upon the successes of the second
generation hovercraft. This has meant improving the reliability and
performance of the mechanical and electrical systems, as well as modifying the
shape of our catamaran hulls.
First hover test:
The test was a success: the modifications to the center of gravity have
balanced the boat properly and the new Etek motor has proven more than capable
of hovering the boat for an extended period of time. While we successfully
used the thrust fan to move the craft, the air rudder steering system was not
operational for this test.
on the following links to see video clips of the test.
Hovercraft starting up
Hover in action
have begun the process of widening the pontoons. With the stricter
enforcement of the rule against major hull modifications between races we have
needed to mount the pontoons in a fixed position (we used to move them between
races to switch between hover mode and endurance catamaran mode).
When in hover mode the pontoons have too deep a draft to come out of the water
when the boat hovers. To fix this problem we have decided to widen the
pontoons and thus decrease the draft. We have epoxied a set of ribs to the
hull over which we will stretch Dacron. This solution will not adversely
increase the weight and will also not require many man hours to complete.
Here you can see
the ribs being epoxied onto the pontoons.
The New Boat
hovercraft mostly finished, the team decided that we wanted to try a new
challenge. After looking at several different options the team fixed on
building a hydrofoil equipped boat due to the very low drag characteristics of
hydrofoils. Hydrofoils present a unique engineering challenge, especially
in Solar Splash where available power is so limited.
This year, the
team is concentrating on building the new hull with its associated mechanical
and electrical systems. We will enter this boat in the 2005 Solar Splash
competition as a normal displacement mono-hull and in the following year we will
work on adding the hydrofoils to the hull. This two year strategy allows
the team to focus this year on designing and testing the boat's systems to
ensure they are operating soundly, while leaving the next year to design and
test various hydrofoil configurations.
The team has
decided to build a full displacement mono hull out of foam and fiberglass.
This combination will provide, among other things, the lightest weight possible,
excellent endurance race performance (where most of the points are won), and
good strength as well as durability.
16' LOA, ~15.5' LWL, 30"Beam, ~5" Draft.
and analysis has been employed to design the hull and place the components
inside it. Additional physical scale modeling testing has been conducted
to analyze lateral stability. The results have shown that the craft will
pass stability inspections at the race, and provisions are being made for
stabilization floats on the bow hydrofoil support struts should they be needed.
Our initial model is pictured below with hydrofoils.
We have revised the hull design for lower drag: