New Record For Solar-Powered Autonomous Flight: 28 Hours Without Refueling 20
Hallie Siegel describes a new and impressive achievement for solar-powered flight: keeping a drone aloft for more than a full day. From the article: To actually pull it off has required a fair bit of innovation in flexible solar cells, high energy density batteries, miniaturized MEMS and CMOS sensors, and powerful processors ... but researchers at ETH Zurich have just recently managed to keep their unmanned UAV aloft for 28 hours without any fuel, building on their previous record by over an hour. Having more than 24 hours of endurance is important because overcast skies can inhibit recharging and poor weather or high winds can affect power consumption.
Good achievement, but (Score:2)
But why not just use a lighter-than-air vehicle and stay aloft for months?
Re:Good achievement, but (Score:5, Informative)
Airships only exceed optimized airplanes in transport efficiency for extremely large sizes and severely limited speeds. Solar/battery airplanes can already exceed one diurnal cycle, so there is no reason in principle why they themselves cannot stay aloft for months.
Airships are subject to problems that do not apply at all to airplanes. A major one is that they are subject to serious lift variations due to varying degrees of heating differential to the surrounding atmosphere. This can only be countered via engine power or by expenditure of ballast and valving of gas. This has traditionally been the ultimate limit to their endurance, which has never exceeded 11 days in practice.
Re: (Score:2)
Makes sense. How about a hybrid approach with a lighter-than-air vehicle shaped to generate lift? Does the extra size needed for the lighter than air gasses cause more loss from drag than it saves by reducing the energy needed to stay aloft?
Re: (Score:1)
Using solar energy to compress the gas instead of leaking it?
Question (Score:2)
If the craft can fly for greater than one diurnal cycle, why cannot it fly indefinitely?
Re: (Score:1)
Nope, RTFA, batteries had higher charge at the end of the 28 hour flight than at the start.
Re: (Score:2)
Two cloudy days in a row.
Fuel. (Score:3)
I do not think that word means what you think it means.
28 hours? (Score:4, Funny)
Small difference between 28 hours and many weeks (Score:2)
Not a record, not even close (Score:4, Informative)
Qinetiq Zephyr [wikipedia.org] flew for "336 hours and 22 minutes (2 weeks / 14 days)".
I'm pretty sure I remember a similar but much longer flight, but I can't find the details. Regardless, 28 hours isn't very impressive compared to 336.
Re: (Score:3)
From the article:
"thereby setting a new *Swiss* endurance record for unmanned solar-powered flight, and improving upon the previous internal record (ASL’s Sky Sailor) by a over an hour."
(emphasis mine)
So the summary overstates the record by most of a planet.
Unmanned UAV? (Score:2)
As opposed to a manned unmanned aerial vehicle?
Top Packers and Movers (Score:1)