Re: 500 mile flight (II)
Ralph Wallio, W0RPK <wallio@...>
All of these "around-the-world" attempts were flying in the busy 15-35kft
altitude range but they were using altitude encoded radar transponders and
in constant communication with air traffic control. ATC could always
identify them on radar and vectored more maneuverable aircraft away from
them. In my opinion, these manned flights are not reasonable operational
models for much less significant unmanned missions.
It is possible to fly a transponder, even with encoding, in an unmanned high
altitude payload but they are expensive, ~$2,000, and they use a lot of
power. It is my general impression that without a transponder and constant
communications with ATC, the FAA would consider an unmanned balloon cruising
at 15-35kft to be derelict and a threat to air navigation.
Summer winds aloft above 60kft would not be useful for a west-to-east
flight. If we want to fly during the summer above controlled air space
(above 60kft) we would have to go east-to-west at a much slower speed of
4-8m/s (7-15kts, 9-18mph). A record breaking 710 mile flight would
therefore take 710/13.5 = ~52 hours which is far two long for an amateur
zero pressure mission. (This MZW-derived estimate compares nicely with
NASA/NSBF missions in August 2000 from south central Iowa to southeastern
Nebraska, roughly 200 miles in 16 hours, averaging 12.5mph.)
Timing this mission for GPSL-2003 would be a problem because attendees are
already completely scheduled with a busy symposium and multiple flight
schedule. There would be very little, if any, time available for attendees
to participate in a complicated long-duration long-haul mission.
All of this takes me back to a west-to-east 60-80kft mission during the
winter. Ascent and descent would be in controlled airspace but only for an
hour each. The roughly 24 hour cruise would be above controlled air space
so a transponder and constant ATC contact would not be required. It is easy
to imagine a payload of two <6-pound packages, including ballast dumping, so
the flight would be exempt.
A winter flight would allow the eastern recovery troops to dedicate a
weekend to the mission while driving long distances to be in the right place
at the right time for descent and touchdown. Home stations at intermediate
distances, spaced ~200 miles apart, could capture telemetry and report their
observations. They could also be equipped for an "emergency" cutdown
command if system failure allowed descent into controlled air space.
It is reasonable to believe that a recovery team can be put together at this
end (Iowa, Illinois, et al.), that intermediate stations can be recruited
for any possible flight track, and that winds aloft data and track
prediction processes are dependable. I believe this can be done and safely.
TNX es 73 de Ralph Wallio, W0RPK
Optimal solutions do not always exist