- Email: [email protected]
Map lag
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THE LAST WORD Upside drone Why do military drones look so different from military aircraft? For example, their tail fins point downwards.
n Abraham Karem was the designer of the Albatross prototype, which later became the Predator drone. This is probably the drone with which we are most familiar from news reports on TV. He notes that drone makers have a distinct advantage in not needing to consider accommodation or life support for a pilot. Karem designed for endurance, giving his drone long wings to maximise lift and stability over speed and agility. He chose a propeller-driven engine because these are more fuel-efficient than jet engines, and usually easier to maintain. He located the propulsion at the rear of his drone to minimise any interference to sensors housed in the nose. The distinctive split downward-facing tail of the Predator exists to protect the propeller during take-off and landing. If the pilot attempts to come in at too steep an angle, the outer tails act like a pair of skids to prevent the propeller from striking the ground. The nose is bulbous to accommodate the satellite-communications equipment required to remotely pilot the drone. The Predator was not designed as an armed aircraft, but for use as a surveillance system. There are many other designs for drones
The writers of answers that are published in the magazine will receive a cheque for £25 (or US$ equivalent). Answers should be concise. We reserve the right to edit items for clarity and style. Please include a daytime telephone number and an email address if you have one. New Scientist retains total editorial control over the published content. Reed Business Information Ltd reserves all rights to reuse all question and answer material that has been
out there. Not all use propeller propulsion, and some are designed to benefit from modern stealth technologies. There is also work going on to develop uncrewed, remotely piloted combat aircraft. These will probably look more like crewed versions because they will need to be far more agile. Thomas Woods Eyemouth, Berwickshire, UK
Map lag On ancient maps, India is usually portrayed as much smaller than it is nowadays. Sometimes it’s perhaps only half the size. Surely mariners of the time could judge distances, especially along a relatively even coastline. What is the reason for the discrepancy?
route maps). This preservation of compass direction, as well as the accurate depiction of coastal features, is what sailors cared about – and they were the most important customers for maps at the time. But the Mercator projection has a huge drawback. It makes a 40-kilometre circle around the North Pole as wide as the 40,000-kilometre equator. Africa looks smaller than Greenland when it is actually 14 times larger, and India looks tiny. So an 1855 alternative called the Gall projection was revived in 1973 as the Peters projection. This squashes the vertical distance near the poles to make up for the inherent horizontal expansion. The result is that northern countries (and Australia) are unrecognisable, but the relative area of each country is conserved. If you are prepared to give up on rectangular maps, a semi-oval is a good compromise, although things at the edges still suffer: the 1805 Mollweide map is a popular
n The root cause of India’s varying size is that you can’t peel the surface off a sphere and lay it flat without distorting it. Imagine trying to do so with orange peel. You have to choose how to distort “Drones have long wings it: you can preserve area, distance to maximise lift and stability over speed or direction, but not all of them. This compromise is inherent in all and agility” map projections of Earth’s surface. There is no perfect depiction, equal-area projection, and the and choosing the appropriate one National Geographic Society uses depends on the map’s purpose. the 1921 Winkel Tripel projection. The 16th-century Mercator Online maps such as Google projection preserves compass Maps still use a simplified directions: the north-south and Mercator projection because east-west lines are straight preserving compass directions on (although all other straight a rectangle is their main purpose. journeys look curved, as you may Ron Dippold have seen on in-flight aircraft San Diego, California, US
submitted by readers in any medium or in any format and at any time in the future. Send questions and answers to The Last Word, New Scientist, 110 High Holborn, London WC1V 6EU, UK, by email to [email protected] or visit www.newscientist.com/topic/lastword (please include a postal address in order to receive payment for answers). Unanswered questions can also be found at this URL.
This week’s questions Rules of attraction
In my business, we use rareearth magnets that are about 32 millimetres across and 8 millimetres thick. Four of them will securely hold a 1-kilogram device on a working bulldozer. But when a delivery of 1000 magnets arrives, the package has nearly no magnetic field around it. Why is that? Chris Seymour Lota, Queensland, Australia Mystery measure
Why do some imperial tape measures have a mark at 16, 32 and 48 inches, and so on? John Jarvis Bristol, UK Cutting noise
Could the treatment of windturbine blades to substantially reduce noise, as described in New Scientist (20 June 2015, p 19), also be applied to lower the noise of helicopters? Geoff Barnes Brisbane, Queensland, Australia Resist and multiply
We hear a lot about bugs, flies and fungi gaining resistance to pesticides and other chemical treatments, making such solutions futile. If this is the case, shouldn’t humans gain resistance to threats such as harmful chemicals and bugs? And if so, how quickly? Nimesh Nambiar Dubai, United Arab Emirates
Question Everything The latest book of science questions: unpredictable and entertaining. Expect the unexpected Available from booksellers and at newscientist.com/questioneverything
THE LAST WORD Upside drone Why do military drones look so different from military aircraft? For example, their tail fins point downwards.
n Abraham Karem was the designer of the Albatross prototype, which later became the Predator drone. This is probably the drone with which we are most familiar from news reports on TV. He notes that drone makers have a distinct advantage in not needing to consider accommodation or life support for a pilot. Karem designed for endurance, giving his drone long wings to maximise lift and stability over speed and agility. He chose a propeller-driven engine because these are more fuel-efficient than jet engines, and usually easier to maintain. He located the propulsion at the rear of his drone to minimise any interference to sensors housed in the nose. The distinctive split downward-facing tail of the Predator exists to protect the propeller during take-off and landing. If the pilot attempts to come in at too steep an angle, the outer tails act like a pair of skids to prevent the propeller from striking the ground. The nose is bulbous to accommodate the satellite-communications equipment required to remotely pilot the drone. The Predator was not designed as an armed aircraft, but for use as a surveillance system. There are many other designs for drones
The writers of answers that are published in the magazine will receive a cheque for £25 (or US$ equivalent). Answers should be concise. We reserve the right to edit items for clarity and style. Please include a daytime telephone number and an email address if you have one. New Scientist retains total editorial control over the published content. Reed Business Information Ltd reserves all rights to reuse all question and answer material that has been
out there. Not all use propeller propulsion, and some are designed to benefit from modern stealth technologies. There is also work going on to develop uncrewed, remotely piloted combat aircraft. These will probably look more like crewed versions because they will need to be far more agile. Thomas Woods Eyemouth, Berwickshire, UK
Map lag On ancient maps, India is usually portrayed as much smaller than it is nowadays. Sometimes it’s perhaps only half the size. Surely mariners of the time could judge distances, especially along a relatively even coastline. What is the reason for the discrepancy?
route maps). This preservation of compass direction, as well as the accurate depiction of coastal features, is what sailors cared about – and they were the most important customers for maps at the time. But the Mercator projection has a huge drawback. It makes a 40-kilometre circle around the North Pole as wide as the 40,000-kilometre equator. Africa looks smaller than Greenland when it is actually 14 times larger, and India looks tiny. So an 1855 alternative called the Gall projection was revived in 1973 as the Peters projection. This squashes the vertical distance near the poles to make up for the inherent horizontal expansion. The result is that northern countries (and Australia) are unrecognisable, but the relative area of each country is conserved. If you are prepared to give up on rectangular maps, a semi-oval is a good compromise, although things at the edges still suffer: the 1805 Mollweide map is a popular
n The root cause of India’s varying size is that you can’t peel the surface off a sphere and lay it flat without distorting it. Imagine trying to do so with orange peel. You have to choose how to distort “Drones have long wings it: you can preserve area, distance to maximise lift and stability over speed or direction, but not all of them. This compromise is inherent in all and agility” map projections of Earth’s surface. There is no perfect depiction, equal-area projection, and the and choosing the appropriate one National Geographic Society uses depends on the map’s purpose. the 1921 Winkel Tripel projection. The 16th-century Mercator Online maps such as Google projection preserves compass Maps still use a simplified directions: the north-south and Mercator projection because east-west lines are straight preserving compass directions on (although all other straight a rectangle is their main purpose. journeys look curved, as you may Ron Dippold have seen on in-flight aircraft San Diego, California, US
submitted by readers in any medium or in any format and at any time in the future. Send questions and answers to The Last Word, New Scientist, 110 High Holborn, London WC1V 6EU, UK, by email to [email protected] or visit www.newscientist.com/topic/lastword (please include a postal address in order to receive payment for answers). Unanswered questions can also be found at this URL.
This week’s questions Rules of attraction
In my business, we use rareearth magnets that are about 32 millimetres across and 8 millimetres thick. Four of them will securely hold a 1-kilogram device on a working bulldozer. But when a delivery of 1000 magnets arrives, the package has nearly no magnetic field around it. Why is that? Chris Seymour Lota, Queensland, Australia Mystery measure
Why do some imperial tape measures have a mark at 16, 32 and 48 inches, and so on? John Jarvis Bristol, UK Cutting noise
Could the treatment of windturbine blades to substantially reduce noise, as described in New Scientist (20 June 2015, p 19), also be applied to lower the noise of helicopters? Geoff Barnes Brisbane, Queensland, Australia Resist and multiply
We hear a lot about bugs, flies and fungi gaining resistance to pesticides and other chemical treatments, making such solutions futile. If this is the case, shouldn’t humans gain resistance to threats such as harmful chemicals and bugs? And if so, how quickly? Nimesh Nambiar Dubai, United Arab Emirates
Question Everything The latest book of science questions: unpredictable and entertaining. Expect the unexpected Available from booksellers and at newscientist.com/questioneverything