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33 votes

Flying upside down without feeling it

This sounds like a barrel roll. This is a corkscrew-like flight path in which the airplane rotates around an axis between its longitudinal and pitch axes by flying along a path which lies on the ...
Peter Kämpf's user avatar
27 votes
Accepted

What is a "rapid changes in gravitational force"

The TSIB preliminary findings and the BBC use "G" as a short-hand for g-force, which is not the same thing as "gravitational force". They are using the wrong terminology here. The ...
Bianfable's user avatar
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23 votes

Why a kite flying at 1000 feet in "figure-of-eight loops" serves to "multiply the pulling effect of the airflow" on the ship to which it is attached?

The giant kites mentioned aren't the quadrilateral kites kids fly. They are airfoil shaped parachutes with open noses that generate lift as they move through the air. Ram air pressure inflates them ...
Pilothead's user avatar
  • 20.7k
21 votes

Why does a sudden tailwind/headwind change IAS?

Why that happens is due to the aircraft's inertia. Consider a fairly simple case: an aircraft is flying due north, straight & level, with a constant 100 knots of indicated airspeed (KIAS) and a 10 ...
Ralph J's user avatar
  • 51.8k
15 votes

If I am at absolute ceiling, can I climb further by trading airspeed for altitude?

Yes, you can zoom climb. While you have no excess power to sustain a climb, if you just pull back you can gain altitude briefly. You will rapidly lose airspeed and will stall if you attempt to keep ...
Chris's user avatar
  • 16k
14 votes
Accepted

Why is a flat turn less efficient than a coordinated turn?

I don't believe Chris's answer is incorrect, however I'd like to pose an alternate way of explaining what happens: As you have noted, turning requires a horizontal force perpendicular to velocity, and ...
ThatCoolCoder's user avatar
13 votes
Accepted

How to slow down while maintaining altitude

To maintain altitude, lift must be equal to weight. The first question is, does slowing down reduce the amount of lift we have? We can look at the lift formula for the answer: $$\mbox{Lift} = C_l \...
Ben's user avatar
  • 14.5k
12 votes

Why a kite flying at 1000 feet in "figure-of-eight loops" serves to "multiply the pulling effect of the airflow" on the ship to which it is attached?

Have you ever flown a dual line kite? If you keep it steady it will climb until it reaches a steady state and until it is mostly horizontal and only pull minimally on the lines. If however you turn it ...
ratchet freak's user avatar
11 votes

If I am at absolute ceiling, can I climb further by trading airspeed for altitude?

Vx and Vy converge at the absolute ceiling, at an airspeed that is higher than stall speed. So yes, you can still pull back on the stick or yoke and temporarily climb a bit. Of course, you will soon ...
quiet flyer's user avatar
  • 22.7k
9 votes

What is the load factor in a descending turn?

Due to the descent the load factor wouldn't increase I have to disagree with your first CFI, even though I suspect that he was misunderstood. Your load factor due to descent will decrease with the ...
Peter Kämpf's user avatar
9 votes
Accepted

How does the horizontal component of lift when flying at a bank angle cause the aircraft to follow a circular path?

You are absolutely right that the horizontal force perpendicular to the direction of flight cause a side slip. The rotation comes from the vertical stabilizer which as soon as a side slip occurs ...
DeltaLima's user avatar
  • 83.5k
8 votes

Flying upside down without feeling it

I guess it means the pilot managed to provide a net 1 g of acceleration upwards, so the body and any other object experienced the usual head-to-toe force. But to achieve that (1G) acceleration it ...
quiet flyer's user avatar
  • 22.7k
8 votes

Why is a flat turn less efficient than a coordinated turn?

The sideslip angle. An airplane's drag increases with sideslip angle. In a coordinated turn, the nose is always pointed into the relative wind, and so there is not as much of an increase in drag. ...
Chris's user avatar
  • 16k
7 votes

Why the heavier the aircraft is, the higher the airspeed must be to obtain the same glide ratio?

In still air, the glide ratio of an aircraft is the same as its L/D ratio (more info here). The L/D ratio of a given aircraft depends only on its angle of attack; a given AoA will always correspond to ...
Aditya Sharma's user avatar
6 votes

Did the dog-tooth notches in the wing of the F-8 Crusader really have anything to do with "yaw stability"?

The usual way in which such devices work is that they provide a barrier between separated flow and the ailerons. The vortex coming from the notch ensures that the flow separation from the inboard wing ...
ROIMaison's user avatar
  • 7,447
6 votes

If I am at absolute ceiling, can I climb further by trading airspeed for altitude?

At the absolute ceiling, you have no extra engine power to push you through the air any faster, so you cannot add lift to climb by pushing the power lever further forward - you are already maxed out. ...
niels nielsen's user avatar
6 votes

If in a coordinated turn, the horizontal lift vector is equal to the Centrifugal force. Then how is the aircraft still turning?

The forces in the first pictures would be as shown if you are observing situation from reference frame connected to the turning airplane. Then, in this reference frame, the airplane is not moving and ...
Martin's user avatar
  • 2,766
6 votes

If in a coordinated turn, the horizontal lift vector is equal to the Centrifugal force. Then how is the aircraft still turning?

How does the Aircraft continue to turn when both the Horizontal component of lift and the centrifugal force are equal? Those pictures are not 100% correct. To enter and keep a turn, a force toward ...
sophit's user avatar
  • 13.5k
6 votes

In a straight and level flight if thrust is equal to drag how is aircraft moving forward?

Per Newton's first law, A body remains at rest, or in motion at a constant speed in a straight line, except insofar as it is acted upon by a force. You need excess thrust to get up to speed. But ...
Sanchises's user avatar
  • 13.4k
5 votes

Why a kite flying at 1000 feet in "figure-of-eight loops" serves to "multiply the pulling effect of the airflow" on the ship to which it is attached?

I think the reason is to maintain the optimum angle of attack, while also positioning the kite lines so they pull the ship forward. It probably only helps when the ship is sailing at certain angles ...
Robin Bennett's user avatar
5 votes
Accepted

How does the lift force stop increasing itself after a certain point?

It seems like the lift force would very quickly increase with airspeed (velocity). What I am unsure about is, what forces counteract lift to prevent it from reaching an extremely high value. Let's ...
Thomas Perry's user avatar
  • 1,392
5 votes

Flying upside down without feeling it

Peter Kämpf has the right idea here. It sounds very much like the pilot is doing positive G or so-called “Gentlemen’s aerobatics”. Aileron rolls, barrel rolls, and even some variants of inside loops ...
Romeo_4808N's user avatar
  • 74.1k
5 votes

If in a coordinated turn, the horizontal lift vector is equal to the Centrifugal force. Then how is the aircraft still turning?

The centrifugal force is produced by the act of turning. If you weren't turning, it would be zero. If it were zero, you would have an imbalance of forces which would cause an acceleration that would ...
Rob McDonald's user avatar
  • 13.1k
5 votes

How does the horizontal component of lift when flying at a bank angle cause the aircraft to follow a circular path?

Key point: in a steady-state turn, net torque on the airplane must be zero. Net force on the airplane however is not zero-- there must be a horizontal force toward the center of the turn. This is ...
quiet flyer's user avatar
  • 22.7k
4 votes
Accepted

Why does bank angle have no effect on pivotal altitude?

Assume zero wind. The airspeed $V$, turn radius $R$, gravitational acceleration $g$ and bank angle $\theta$ obey the relation $\frac{V^2}{R} = g\tan\theta$. Meanwhile, at the pivotal altitude $H$, the ...
Foster Boondoggle's user avatar
4 votes

How does mass affect rate of turn?

You have stumbled on an intriguing and fundamental aspect of Physics, the equivalence of Gravitational Mass and Inertial Mass. Gravitational mass is the "m" in the equation that is used to ...
Charles Bretana's user avatar
4 votes

Why does a sudden tailwind/headwind change IAS?

Let's suppose that our airplane possesses a speed of 100kts in respect to earth (speed measured for example via a GPS system) and it's flying into a windy air which has a speed of 20kts (measured for ...
sophit's user avatar
  • 13.5k
4 votes

How does the lift force stop increasing itself after a certain point?

What I am unsure about is, what forces counteract lift to prevent it from reaching an extremely high value The airplane disintegrating is what would stop aerodynamic forces to grow too much. That's ...
sophit's user avatar
  • 13.5k
4 votes

How to slow down while maintaining altitude

Consider the four forces acting on an aircraft in equilibrium: Drag must exceed thrust in order to decelerate. Presuming that you don't have speed brakes to increase drag, the only way to slow down ...
Michael Hall's user avatar
  • 26.9k
4 votes

Longitudinal/Lateral CG envelope for hoist operations

Presuming that the winch is in a fixed location, (not on a track that allows it to move fore and aft or sideways) the longitudinal and lateral center of gravity of the helicopter would not change as ...
Michael Hall's user avatar
  • 26.9k

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