OUR TAX DOLLARS AT WORK

, July 11 2001 I got to see the NASA experimental plane Helios close up. The above is an artist's rendition since the plane has yet to actually fly. There have been several postponements due to weather, computer glitches, and what-not. The next scheduled time for its maiden flight is tomorow morning.

Actually this is the latest in an ongoing NASA project. An earlier version called Pathfinder (with a wingspan of about 140 feet) was flown here on Kauai a couple of years ago - reaching an altitude of 70,000 feet. There are two flights planned for this $15 million dollar test vehicle (with a wingspan of some 270 feet - almost the length of a football field) - the first to 80,000 feet and the second to 100,000 feet.  At those altitudes, there is very little air to provide lift so wing span is critical. There is some sort of theoretical limit of 125,000 feet with greater wingspan.

Both planned test flights will start at 8 AM and last until approximately midnight. The solar panels covering the wing will power the electric motors during the daylight hours and lithium battery power will be used to bring the plane down.

What is the ultimate goal? In other words why are they spending our tax money?  The concept is that the plane can cruise indefinitely at 100,000 feet - well above all the weather patterns. It can be used to measure the 'ozone hole', for earth surveys,  or to provide communication coverage at far less cost that satellites. It can be landed every 6 months or so to check for wear or to update equipment.

But this is a long way off. The current efficiency of the solar panels, vs their weight, will only allow for useful flight at latitudes between 25º North and 25º South latitudes (i.e. - the sun is overhead). Interestingly the bottom of the wing is transparent so that the solar panels pasted on the top get not only direct sunlight, but also that reflected from the earth. The plane gets greater power when flying over clouds. The next flights of helios are scheduled for 2003 (apparently no great rush in NASA) to test the next phase - a fuel cell. The idea is to use excess daytime energy to hydrolyze water and store the hydrogen and oxygen under pressure. The fuel cell then combines the elements generating electricity to run the plane at night - retaining the water in the closed system for re-use the next day.

The entire plane is covered by photovoltaic cells. The cost of these cells contributes $10 million to the total cost of the plane. They generate the amount of electricity used by 4 or 5 average size homes. This thought might give some pause to those who advocate converting everything to solar power. As you can imagine, weight is critical. The entire Helios weighs a mere 1650 # (the aluminum transport cradle weighs over twice that much. Extremely thin (and light) silicone photovoltaic cells were used - both for weight as well as cost. (apparently $10 million is cheap?).

The plane is too wide to fit in the hangar - so it is broken up into 2 sections, here seen facing each other - each on a separate dolly. The plane sections are attached and removed from the dolly at the flight line. It can take off at about 20 Mph - requiring a runway of a mere 100 feet (albeit 300 feet wide) - and about 500 feet to land.  Flying the plane is done from the ground. The plane is equipped with a few minature cameras (and other telemetry).  The white strip behind the solar panels is made up of a series of ailerons controlled by off the shelf model airplane actuators. The 6 center motors are set to fly at a uniform speed to each other. The outboard 4 motors on either end can be individually speed controlled to turn and bank the aircraft. The motors are air cooled and the propellers have a fixed pitch.

Talk about lightweight - one guy held up the wing while another one put in the prop seen holding it up. This was part of the pre-flight check going on while we were there. The only metal used (other than presumably the motors) is in the wheel assemblies in the pods you can see above. The pods contain the onboard electronics as well as the batteries. Eventually they will be the home for the fuel cell. The plane as currently configured has a payload of about 200# - not nearly enough for the proposed fuel cell.

The wing looked just like those balsa wood model airplanes we used to make - gluing the pieces together on wax paper and covering it with tissue paper. Just back from the leading edge of the wing is a rigid spar made out of some very lightweight exotic material which provides all of the strength. The wings are made to bend and flex in flight. The skin is a transparent mylar-like material. Looking up from the bottom you can see the underside of the solar panels which are glued to the top. The ribs are as flimsy as they look - they feel like the thin plastic that might separate layers in a box of chocolates.

The plane is made in 6 section so it can be shipped. It lives in CA  Simi valley when not here in Kauai. The sections are joined together with what looks suspiciously like duct tape - although my guess is that it more expensive. You can also see the ailerons (flaps?) on the trailing edge.

The flight control center does not look like Cape Canaveral. But everyone seemed busy as a bee doing the pre-flight check.

Just thought I might like to share what is going on with a few of our tax dollars. This could possibly portend some future advances. It was worth the 4 hour roundtrip to see it.

Aloha   Stan

Alas! The Helios crashed into th eocean on a later flight here on Kauai!!