Flying Batteries For Drones

Power is the bane of drone pilots. You’d like to fly longer which means a bigger battery. But a bigger battery will weigh more which leads to less flight time. You have to strike a balance and for most consumer drones that balance is about 20 minutes of flight time, more or less. Researchers at Berkeley have a different idea: don’t use a bigger battery, but simply replace the battery in flight.

The idea isn’t completely new. After all, many planes refuel in flight — a technically sophisticated operation, but it occurs every day. The scheme here is to have a primary battery and a secondary battery. When the secondary battery is low, the drone ejects it while running on the primary battery. Another secondary battery flies to the drone and docks with it becoming the new main power source.

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Gatwick Drone Incident: Police Still Clueless

Quietly released and speedily buried by Parliamentary wrangles over Brexit is the news that Sussex Police have exhausted all lines of inquiry  into the widely publicised drone sighting reports that caused London’s Gatwick Airport to be closed for several days last December. The county’s rozzers have ruled out 96 ‘people of interest’ and combed through 129 separate reports of drone activity, but admit that they are no closer to feeling any miscreant collars. There is no mention of either their claims at the time to have found drone wreckage, their earlier admissions that sightings might have been of police drones, or even that there might have been no drone involved at all.

Regular readers will know that we have reported extensively the sorry saga of official reactions to drone incidents, because we believe that major failings in reporting and investigation will accumulate to have an adverse effect on those many people in our community who fly multi-rotors. In today’s BBC report for example there is the assertion that 109 of the drone sightings came from “‘credible witnesses’ including a pilot and airport police” which while it sounds reassuring is we believe a dangerous route to follow because it implies that the quality of evidence is less important than its source. It is crucial to understand that multi-rotors are still a technology with which the vast majority of the population are still unfamiliar, and simply because a witness is a police officer or a pilot does not make them a drone expert whose evidence is above scrutiny.

Whichever stand you take on the drone sightings at Gatwick and in other places it is clear that Sussex Police do not emerge from this smelling of roses and that their investigation has been chaotic and inept from the start. We believe that there should be a public inquiry into the whole mess, so that those embarrassing parts of it which they and other agencies are so anxious to quietly forget can be subjected to scrutiny. We do not however expect this to happen any time soon.

Keystone Kops header image: Mack Sennett Studios [Public domain].

Aussies Find The True Meaning Of Drone Flight

Ah, stereotypes. Once they’ve solidified it’s surprisingly hard to shake them. When non-Australians think of a generic Aussie then, the chances are that a Crocodile Dundee type of character will spring to mind — a ‘Strine-speaking outdoorsman with a beer in hand. This group of Aussies aren’t helping the case, with a video posted by Australian drone retailer UAVme and featured by ABC News where a large multirotor lifts a guy in a lawn chair, beer in hand, over a lake to do some fishing.

Antics aside, having enough capacity to lift a person is pretty impressive. The drone in question appears to be a large hexacopter frame with rotors both below and above the boom, achieving an unusual dodecacopter configuration.

Of course we’re entertained by the sight, who wouldn’t envy them a spin under a drone in the relative safety of an environment where an unscheduled landing merely means getting wet? It seems Austrailia’s Civil Aviation Safety Authority isn’t quite so happy though, as ABC reports the usual chorus of condemnation. Entertainingly though it’s unclear whether or not our plucky adventurer — named as [Sam Foreman] — has in fact broken any laws given that he’s not flown in restricted airspace, over people or habitation, or above the legal altitude.

This isn’t the first such story we’ve brought you from Down Under, back in 2016 an Aussie landed in hot water for picking up a Bunnings sausage in a bun with his drone.

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Safety Systems For Stopping An Uncontrolled Drone Crash

We spend a lot of time here at Hackaday talking about drone incidents and today we’re looking into the hazard of operating in areas where people are present. Accidents happen, and a whether it’s a catastrophic failure or just a dead battery pack, the chance of a multi-rotor aircraft crashing down onto people below is a real and persistent hazard. For amateur fliers, operating over crowds of people is simply banned, but there are cases where professionally-piloted dones are flying near crowds of people and other safety measures need to be considered.

We saw a skier narrowly missed by a falling camera drone in 2015, and a couple weeks back there was news of a postal drone trial in Switzerland being halted after a parachute system failed. When a multirotor somehow fails while in flight it represents a multi-kilogram flying weapon widow-maker equipped with spinning blades, how does it make it to the ground in as safe a manner as possible? Does it fall in uncontrolled flight, or does it activate a failsafe technology and retain some form of control as it descends?

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Designing Compact Gasoline Generator Prototype For Drone Use

Lithium batteries and brushless motors helped make multirotor drones possible, but batteries only last so long. Liquid fuels have far greater energy densities, but have not  been widely applied in these roles. [Tech Ingredients] has been experimenting with a compact gasoline-fueled generator, with the aim to extend drone flight times well beyond what is currently possible with batteries (Youtube link, embedded below).

The build began with a single-cylinder, four stroke engine. However, torque spikes and vibration made things difficult. After some iteration, the design settled on employing two single-cylinder two stroke engines, fitted with a timing belt to keep them 180 degrees out of phase. In combination with a pair of balanced flywheels, this keeps vibration to a minimum. Brushless motors are used as generators, combined with rectifier diodes and capacitors to smooth the voltage output. The generator is intended to be used in parallel with a lithium battery pack in order to ensure the drone always has power available, even in the event of a temporary malfunction.

This is a build with plenty of promise, and we can’t wait to see what kind of flight time can be achieved once the system is finished and flight ready. We’ve seen others experimenting with hybrid drones, too.

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DJI Fights Back Over Sensationalist Drone Reporting

Over the past few years the number of reported near misses between multirotors, or drones as they are popularly referred to, and aircraft has been on the rise. While evidence to back up these reports has been absent time and again.

We’ve looked at incident reports, airport closures, and media reporting. The latest chapter comes in the form of a BBC documentary, “Britain’s Next Air Disaster? Drones” whose angle proved too sensational and one-sided for the drone manufacturing giant DJI. They have penned an acerbic open letter to the broadcaster (PDF link to the letter itself) that says that they will be launching an official complaint over the programme’s content. The letter begins with the following stinging critique:

As the world’s leader in civilian drones and aerial imaging technology, we feel it is our duty on behalf of the millions of responsible drone users around the globe, to express our deep disappointment at the BBC’s negative portrayal of drone technology and one-sided reporting based on hearsay.

It then goes on to attack the tone adopted by the presenter in more detail : “overwhelmingly negative, with the presenter frequently using the words ‘catastrophic’ and ‘terrifying’.“, before attacking the validity of a series of featured impact tests and highlighting the questionable basis for air proximity incident reports. They round the document off with a run through the safety features that they and other manufacturers are incorporating into their products.

DJI have pulled no punches in their condemnation of the standard of reporting on drone incidents in this document, and it is a welcome and rare sight in an arena in which the voices of people who know something of multirotors have been rather lonely and ignored. The BBC in turn have responded by saying “its investigation had shown positive uses of drones and that its programmes were fair“.

Over the past few years we have reported on this issue we have continually made the plea for a higher quality of reporting on drone stories. While Britain has been the center of reporting that skews negatively on the hobby, the topic is relevant wherever in the world there are nervous airspace regulators with an eye to any perceived menace. These incidents have pushed the industry to develop additional safety standards, as DJI mentions in their letter: “the drone industry itself has implemented various features to mitigate the risks described”. Let’s hope this first glimmer of a fight-back from an industry heavyweight (with more clout than the multirotor community) will bear the fruit of increased awareness from media, officials, and the general public.

If you’d like to see the BBC documentary in question it will be available for the next few weeks to people who see the Internet through a British IP address.

Thanks [Stuart] for the tip!

The UK Drone Community Fights Back, Gains FOI Admission Of No Tangible Drone Evidence

Regular Hackaday readers will have noted a succession of stories following the reports of drones in the air over British airports and in proximity to aircraft. We’ve consistently asked for a better quality of investigation and reporting into these cases, because so far the absence of reported tangible evidence of a drone being present casts doubt on the validity of the official reaction. For too long the official records of air proximity incidents have relied upon a shockingly low standard of proof when apportioning blame to drone operators, and this situation has contributed to something of a panic over the issue.

It seems that some members of the British drone flying community are on the case though. Airprox Reality Check are a group analysing air proximity reports and linking them to contemporary ADS-B and weather records to identify possible explanations. They have devised a rating system based upon a number of different metrics in an attempt to quantify the reliability of a particular report, and they are tabulating their analysis of air proximity reports on a month by month basis. This includes among many analyses such gems as Airprox Report #2019046, in which an Embraer 170 flying at 9000 feet and 20 km offshore reported a drone in close proximity. The Airprox Reality Check analysis points out that no known drone could manage that feat, and refers to a passing Boeing 737 revealed through ADS-B data as a more likely culprit.

Their latest news is that they have made a Freedom of Information request to the Air Proximity Board, asking for what evidence the Board has of a drone having been involved in any of the over 350 incidents in UK airspace having been reported as involving drones. The official response contains the following quote:

in all cases UKAB has no confirmation that a drone has flown close to an aircraft other than the report made by the pilot(s). Similarly, other than from the report of the pilot(s), UKAB has no confirmation that a drone was involved.

This confirms the view of the multirotor and drone community that has been reported by Hackaday in the past, that the whole British drone panic has been based upon unreliable and uncorroborated reports from eyewitnesses with little direct experience of multirotors. If any irresponsible drone operator is flying into close proximity with aircraft or otherwise into protected airspace then it goes without saying that they should be prosecuted, yet it seems that the community is being punished as though this had happened when the reality is that no such acts are proven to have occurred.