There is a modestly popular televisual series called "How Do They Do That?", which explains how people do things like building suspension bridges, digging tunnels or producing 25,000 fish-fingers per second. Along with "How It's Made", it addresses the many hows of modern life.
Proposed, "Why Do They Do That?", a series which explains the reasons behind all the mysterious things that workmen and officials do for no apparent purpose. For example, why do they leave roadwork speed restrictions in place when it's August and all road repairpeople are on holiday? Why do they close the boarding gate thirty minutes before departure, then leave the plane standing there until 12 minutes past departure? Why do they retract the landing gear as soon as the plane leaves the ground, but lower it 20 miles before landing? Why do lorry drivers on 2-lane motorways overtake each other at a speed differential of 0.2mph, regardless of the slower lorry's speed? There are of course excellent reasons for all these things, and it would alleviate some degree of angst if we were all told.-- MaxwellBuchanan, May 29 2019 // Why do they retract the landing gear as soon as the plane leaves the ground, but lower it 20 miles before landing? //
<Jumps up and down, waves hand in air/>
Oooh ! Ohhh! We know this one !
On takeoff, the priority is to reduce drag as much and as soon as possible, to maintain airspeed in the climbout. The high-lift devices go/next, to clean the wings up. This allows a power reduction, ostensibly for noise abatement but actually to try and prevent the engine(s) from making an Expensive Noise of a quite different sort.
In aircraft with fixed undercarriages, instead of retracting the undercarriage it is the tradition for the pilot not flying to criticise the pilot flying for poor technique, inadequate personal hygiene, lack of sartorial taste, but most of all for selecting an aircraft with fixed gear.
On landing, it's best to have all drag inducing features activated while there is still a good bit of air underneath the plane, making it possible to adjust engine power (if any) to hopefully give a less uncontrolled rate of descent. It also allows the crew to resume breathing when the "three greens" (gear down and locked) hopefully appear. If they don't, see the previous paragraph on criticism of the pilot flying.-- 8th of 7, May 29 2019 Yes, [8th], we know you know. We were hoping you'd let someone else answer.
I'd always assumed it was because you can tell pretty accurately when you've taken off, but it's difficult to know where or when you're going to land.-- MaxwellBuchanan, May 29 2019 The idea is about an internet video show not about annotations in a black and white no hyperlink python run website from the former century luckily for me with no votes enabled on comments.
For 8th's Anno to count you need to see him at the computer all exited with his own voice over reading the question while in the background you see various types of aircraft retracting their wheels on takeoff and leaving them out on return. Then the program narrator says stay tuned and we'll be back right after the advertisements.
A witty program would have an advertisement for air travel. When continued we are at an airport watching from a drone focusing on something near the runway. It's 8th waving wildly and yelling me me!
Now we watch a few famous accidents and a historical review of landing gear development from the 1950s. Back to the airport where 8th is trying to outshout the motors of a 757. Off to the pilot of a wwi style sea plane who says his name is Ian Tindale and in the passenger seat behind him is Maxwell Buchanan, the host of this new show. He has a scarf with some kind of pastry on a plate flying behind him in the wind and they are both worried because it is not clear when and where they will land.-- pashute, May 30 2019 //...where 8th is trying to outshout the motors of a 757// ...only to get sucked into the engine moments later? Please? Pretty please! :D-- DrBob, May 31 2019 OK, [pashute], you've got the job. When can you start?-- MaxwellBuchanan, May 31 2019 not sure if I've ever witnessed [8th] in a state of exitness.-- po, May 31 2019 I would posit that all of the questions that might be asked by the persistently periapoplectic viewers of this television documentary could be answered by one of the following: (a) cost;(b) safety; (c) lol people are irrational *shrug emoji*It might be worthwhile expanding on (a) and (b), just so people know how the world works, but generally (c) will be Old News.-- calum, Jun 03 2019 What about (d), "limitations of the underlying science/technology ?" ... jetpacks etc. - can be built, can be made (relatively)* safe, not overly expensive - but limited by available hypergols, operational time etc.
*Safer than trying to "fly" without one, anyway.-- 8th of 7, Jun 03 2019 Why did God make the Earth flat? It should be round.-- blissmiss, Jun 04 2019 random, halfbakery