Difference between revisions of "LDBconstraints"
(Created page with '== Long Duration Balloon Project Known Constraints == == Launch == === Time === Optimal launch time: Just after sunset. This optimizes for maximum flight time. The idea is to…')
Revision as of 19:34, 23 August 2010
Long Duration Balloon Project Known Constraints
Optimal launch time: Just after sunset. This optimizes for maximum flight time. The idea is to launch as far before sunrise as possible. Reaching float altitude in the dark allows the helium to be densest when it overflows out the vent. Then at dawn, the sun heats the helium and it expands, with some flowing out of the vent, maintaining altitude.
- Clear of obstructions taller than 50 feet and powerlines for at least 100 yards downwind
- Clear of obstructions taller than 10 feet at least 50 yards downwind
- Some paved surface is recommended for ease of setting out tarps and tools and rolling heavy tanks around.
- absolutely no sharp objects or corners in/on the ground for 100 feet from anywhere the balloon will be while laying on the ground, or while tethered to a ground handler.
- Site should be available for 3 hours before and 3 hours after planned launch time. (most launches do not happen on time, and involve a bit of DIY fixing that delays things)
- Accessible closely by pickup truck - helium T cylinders are over 100lbs
- Recommend that site should not be within controlled airspace classes B, C or D.
- Recommend that site should not allow common flight paths to pass into controlled airspace classes B, C or D. These airspaces extend up to 10,000ft MSL.
- Recommend to inquire with local ATC for where approach/departure paths for high traffic runways are, and avoid flight through these corridors as well.
- Low wind required at time of launch - safe maximum 5MPH, technical maximum 10MPH. Higher than this are likely to damage balloon or injure people holding balloon.
- Clear sky - for airplane safety, balloon should not enter clouds
- Temperature - Any is acceptable, however ensure that the balloon envelope is inflated and remains at outside air temperature if any lift force measurement is to be performed. (do not inflate in a heated hangar, and check lift force in there) When the Jet Stream is ready for balloon insertion, it will be one of the coldest nights of the year.
- Barometric pressure - Any.