Linked Questions

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1answer
2k views

How comes lift is less than weight on take-off? [duplicate]

If $$lift=weight * cos(angle)$$ this means that lift is less than weight during takeoff. Could someone please explain me why it is so
0
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1answer
452 views

Can an airplane lift off the ground when lift is equal to weight? [duplicate]

Can a plane lift off the ground at the point when there is the same amount of lift as weight? Or does lift have to be greater?
17
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7answers
17k views

Does lift equal weight in a climb?

This subject keeps coming up in the discussions and questions such as this one, which asks if lift equals weight in level flight. Good answers there, pointing out that upwards force has many sources. ...
30
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8answers
6k views

Is excess lift or excess power needed for a climb?

As answered in this question, aircraft need excess power - not excess lift - to climb. This is plausible when the aircraft's thrust vector has a vertical component (its nose and engine points upwards),...
16
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4answers
2k views

Do any airplane designs exist that don't involve a flight surface that provides downforce?

Most aircraft maintain longitudinal stability by balancing three forces: The down force acting through the center of gravity (CG) The lifting force acting through the center of lift The down force ...
8
votes
6answers
7k views

Does lift equal weight in level flight?

Does lift equal weight in level flight? Or does it equal weight + down pressure on the tail? Added) Let's say the total weight of the aircraft on the ground was 100,000 lbs, and when it took off and ...
6
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4answers
3k views

How can lift be less than thrust that is less than weight? [duplicate]

Physics in schools teaches two contradictory and mutually exclusive things: That the upward lift force on an airplane in flight equal its weight (Lift = Weight = Mass x Gravity). This is based on ...
14
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4answers
21k views

How do planes descend for landing?

I fly occasionally on a pretty short route on a turboprop (DHC-8). When the airplane descends for landing, I can look through the window and see the ground below getting closer over time. However I ...
7
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3answers
2k views

What is the relationship between power and fuel efficiency?

We were having a discussion in our ground school that power will make the plane ascend or descend and that you use the stick for speed, forward for higher speed and back for slower speed. So does that ...
18
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1answer
3k views

How frequent is the use of spoilers during descent?

Having flown a number of flights as a passenger recently, I observed that: Roughly 50% of pilots used spoilers above FL180 Almost everybody used spoilers to pass the 10,000 feet / 250 knots mark ...
17
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4answers
2k views

Why do planes not fly “backwards” (up from the planes POV) when in a vertical climb?

As suggested by a user in this question, I'd like to ask this question: One of the most basic aerobatic maneuvers is a vertical climb. This can be achieved by just pitching up to what appears to be ...
8
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3answers
3k views

Does an accelerating airplane also start climbing?

Assume that an airplane is flying level. If I understood correctly in this situations there are four forces acting on it: weight, thrust, drag and lift. Lift depends on air density, airspeed, wing ...
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5answers
2k views

Is there any part of a flight where the pilot would pitch down?

Would the pilot ever pitch down (even slightly) during a flight, or would he/she simply reduce power to reduce altitude? This question is not similar to Why do airplanes lift up their nose to climb? (...
7
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3answers
4k views

Is there always a stall if you exceed a specific angle of attack?

So lets consider that the stall angle (=Cl max) of a B747 is at 16° (in clean configuration). Does this mean, that, at whatever speed you are flying (i.e. 500 knots), you would stall if you go on a ...
14
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2answers
1k views

Is trimming for constant speed equal to trimming for constant angle of attack?

My understanding of trim: When you say you have trimmed an aircraft for a constant speed, say 100 mph, you are actually trimming the horizontal stabilizer so that there are no forces on stick (or tail ...

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