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Really should've run this by someone who knows how airplanes work, because they don't do what these hypothetical airplanes do. First off, "elevator flaps" is a

by _moof 4y ago

Really should've run this by someone who knows how airplanes work, because they don't do what these hypothetical airplanes do. First off, "elevator flaps" is a howler. Elevators and flaps are two very different things. More importantly, you don't climb with the elevator; you climb with excess thrust. You can kinda sorta climb a little bit with just elevator, but unless you're making a very minor altitude correction, you'll slow way down and your climb rate will be really anemic, if you climb at all. But most importantly, an airplane won't just keep climbing and do a loop like that (unless you've got a thrust-to-weight ratio greater than one, which, to put it simply, you don't); the wing will stall way before you get anywhere near vertical, and the airplane will just stop flying until the angle of attack is reduced.

tzs 4y ago
> More importantly, you don't climb with the elevator; you climb with excess thrust. You can kinda sorta climb a little bit with just elevator, but unless you're making a very minor altitude correction, you'll slow way down and your climb rate will be really anemic, if you climb at all. So what happens to something like a jet fighter that is in level flight with the engines at maximum power if the pilot uses the elevators to raise the nose?
- _moof 4y ago
  It will climb (and slow down), but again, it's the thrust that's producing the climb, and this is an extreme example that isn't illustrative. Fighter jets produce enormous thrust for their weight with many having thrust-to-weight ratios greater than one. If they weren't air-breathing, they could literally fly into space. A normal airplane, even if it weren't air-breathing, couldn't do that. Depending on the configuration an F-16 has a T/W a little under 1.1, while a transport category aircraft (an airliner) will have a T/W somewhere between 0.20 and 0.35. Totally different performance characteristics.
- p_l 4y ago
  Powered airplanes hide the energy-management nature of climb/descent. Essentially, you have potential energy (altitude) and kinetic energy (speed), and you trade one for the other. For safe range of inputs, your lift is function of pitch and airspeed, with drag as result. Increasing pitch increases lift (most of the time) at expense of increased drag. Lift gets you higher raising your potential energy, which you can spend back on glide, exchanging it for kinetic energy necessary for airflow. With powered plane, you provide extra kinetic energy that can be spent on higher lift. You use your stick to manipulate energy/speed, and in fact it's common to descend while pulling the stick on purpose. A fighter jet with TWR above 1 has enough extra energy that it's going to be able to maneuver rapidly (afterburner/reheat exists for it, even, as jet engines are slow to spool up). Plane with lower TWR, or with significant mass, is going to behave closer to glider (heavy planes like airliners make energy management a big issue)

by _moof 4y ago

tzs 4y ago

> More importantly, you don't climb with the elevator; you climb with excess thrust. You can kinda sorta climb a little bit with just elevator, but unless you're making a very minor altitude correction, you'll slow way down and your climb rate will be really anemic, if you climb at all. So what happens to something like a jet fighter that is in level flight with the engines at maximum power if the pilot uses the elevators to raise the nose?

_moof 4y ago
It will climb (and slow down), but again, it's the thrust that's producing the climb, and this is an extreme example that isn't illustrative. Fighter jets produce enormous thrust for their weight with many having thrust-to-weight ratios greater than one. If they weren't air-breathing, they could literally fly into space. A normal airplane, even if it weren't air-breathing, couldn't do that. Depending on the configuration an F-16 has a T/W a little under 1.1, while a transport category aircraft (an airliner) will have a T/W somewhere between 0.20 and 0.35. Totally different performance characteristics.
p_l 4y ago
Powered airplanes hide the energy-management nature of climb/descent. Essentially, you have potential energy (altitude) and kinetic energy (speed), and you trade one for the other. For safe range of inputs, your lift is function of pitch and airspeed, with drag as result. Increasing pitch increases lift (most of the time) at expense of increased drag. Lift gets you higher raising your potential energy, which you can spend back on glide, exchanging it for kinetic energy necessary for airflow. With powered plane, you provide extra kinetic energy that can be spent on higher lift. You use your stick to manipulate energy/speed, and in fact it's common to descend while pulling the stick on purpose. A fighter jet with TWR above 1 has enough extra energy that it's going to be able to maneuver rapidly (afterburner/reheat exists for it, even, as jet engines are slow to spool up). Plane with lower TWR, or with significant mass, is going to behave closer to glider (heavy planes like airliners make energy management a big issue)