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# Questions tagged [lift]

In aeronautics, lift is a component of aerodynamic force that acts perpendicular to drag, and balances the weight of the aircraft against the effects of gravity to achieve flight. In astronautics however, the lift component of a flight of the spacecraft is a force directly negating and greater of the effects of gravity and atmospheric drag on the body of the spacecraft as it gains altitude, a distance between itself and the body it is lifting off from.

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### Inflatable tank/balloon use for recovery

Hopefully this idea makes sense. Basically if you've seen the space-truck (ROOST), you'll get where I'm going with this. I'm wondering whether an inflatable tank/tank lining could be used to produce ...
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### Is it possible for fuselages to have a negative lift coefficient at positive angle of attacks?

Recently I was interested in the descent phase of the first stage of the falcon 9 launch vehicle. I assumed a long cylinder to represent the first stage. using DATCOM to predict aerodynamics ...
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### Ion propulsion system [duplicate]

Good evening. Is there a formulae to calculate how much lift an ion propulsion system would create on earth, given factors like voltage, load, etcetera? Just a mathematical formulae. That is all I ask ...
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1 answer
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### Lift and Drag of a Model Rocket

Talking about aerodynamic forces in a model rocket, I believe that Lift and Drag are the components of a net force which acts on the Center of pressure. Knowing this, could I affirm that the net ...
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### Drag and lift coefficient tables/plots for Saturn V/Space Shuttle/Other

I'm looking for drag and lift coefficient data to plug into my launch simulation. I could assume constant coefficients, but I'd like to structure my model to accept lookup tables, so I'm looking for ...
2 votes
2 answers
222 views

### Is aerodynamic control in an exosphere possible, in case velocity is high enough?

Exospheres are different than the lower parts of atmospheres (if there are any): the molecules don't collide anymore and it doesn't behave like a gas. However, it still causes some tiny little drag on ...
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4 votes
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### What if you tried to fly a kite on Mars?

I wonder what kite flying might be like on Mars, in one per cent the atmospheric pressure of Earth, about two per cent the Earth's atmospheric density and 38% the Earth's surface gravity. Are there ...
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5 votes
2 answers
939 views

### What would it take for a balloon to reach an altitude of 65 km (214,000 ft) above the Earth's sea level?

Kind of a follow-up question to Could a helium balloon on Mars and on Triton float at air pressures lower than it could on Earth due to the bodies' low gravities?. As stated in the linked question,...
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### Could a helium balloon on Mars and on Triton float at air pressures lower than it could on Earth due to the bodies' low gravities?

The highest altitude ever reached by a balloon above the Earth's surface is about 33 mi (53 km), unmanned above Japan. The 2nd-highest one reached 51.8 km above California. Both reached the lower ...
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### With a 10% increase in Earth's mass, would the Karman line move up or down, and by how much?

This is an exercise to better understand the basic physics and math behind scale height and the Karman line. It was inspired by this answer to Why is FAI considering lowering the Karman Line to 80km? (...
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1 vote
1 answer
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### What if GOCE rolled 90°?

Reading this question: Is GOCE a satellite or aircraft? I wondered what would happen if GOCE rolled 90° in either direction, so that it's solar panels become parallel to Earth's horizon, and then ...
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### Can impact lift produce greater than 1 lift to drag ratio?

At orbital velocity in low circular Earth's orbit, at an altitude where mean free path exceeds cross sectional area of a craft or wing. therefore aerodynamic lift becomes impossible (Consider ...
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3 answers
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### When do aircraft become solarcraft?

Any body travelling through particles undergoes drag. Any body able to generate lift (for instance spheres cannot generate lift) can generate lift if it undergoes drag. First by assuming one body in ...
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1 answer
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### Could a rocket launch off water horizontally in stages us using water and air for lift to save fuel? [duplicate]

A term I have heard is the "water was like class". Meaning that the water had 0 waves. Could a rocket be modified to take off a horizontal surface starting slowly increasing throttle on each stage? ...
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### Could the $C_L$ of the X-15 be calculated from the flight data near the Kármán line altitude?

The "lift coefficient" $C_L$ can be very different for one specific aircraft at different speeds. According to this article from NASA about the lift coefficient: So it is completely incorrect to ...
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1 answer
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### Does an airplane in orbit near the Kármán line altitude, with the air providing lift, ever reach orbital velocity? [duplicate]

The equation for an airplane in orbit with the air providing lift would be: $$\frac{GM_Em}{(R+h)^2} - \frac{\rho(h) v^2 S C_L}{2} = \frac{mv^2}{R+h}$$ $GM_E$ is Earth's standard gravitational ...
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2 votes
2 answers
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### Is the equation showed below the right one for an airplane flying at the Kármán line altitude?

$$\frac{GM_Em}{(R + h)^2} - \frac{ \rho v^2 S C_L}{2} = \frac{mv^2}{R + h}$$ $GM_E$ is Earth's standard gravitational parameter , $R$ is Earth's radius and $h$ the altitude of the airplane above the ...
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-7 votes
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### Does a credible Kármán plane reach escape velocity within 1 minute or does it follow the curvature of the Earth? [duplicate]

Edit: This question is no duplicate because here the dropping of the atmospheric density together with the horizontal line, play an important role. Furthermore none of the answers and question ...
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1 answer
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### Where does the definition of the Kármán line on Wikipedia come from?

According to Wikipedia's article about the Kármán line: The Kármán line is the altitude where the speed necessary to aerodynamically support the airplane's full weight equals orbital velocity ( ...
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2 answers
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### Is it correct to use the vis-viva equation when there are two forces acting on the orbiting body? [closed]

Edit: Although this question seems similar to the question "Is it correct to apply the vis-viva equation to an airplane that flies in a straight line", it is different because there the airplane flies ...
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1 answer
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### Is it correct to apply the vis-viva equation to an airplane that flies in a straight line at the Kármán line?

The vis-viva equation models the motion of an orbiting body and it applies when the only force acting on the body is it's own weight. So is it correct to apply this equation to an airplane that ...
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### Would an autogyro be a good solution for a space re-entry vehicle?

From what I can imagine, using an autorotative maneuver as a re-entry control method would be a good idea because I believe very high lifts would be generated when relative air speed is high (first re-...
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### What's the *calculation* for the altitude near the Kármán line where the lifting force equals the centrifugal force? [duplicate]

Edit: This question is not a duplicate of the associated question and has no answers to it that were posted for that associated question. This question asks specifically for a calculation, the ...
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### Orbital reentry glider with no heat shield

Let's assume a reentry craft designed to not use heat protection like Soyuz or the Space Shuttle, and budget is not an issue. The Concorde max surface temperature was 400 K, so let's use this as a max ...
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### Is the definition of the Kármán line from Wikipedia right? [closed]

Edit: this question is about making clear that the Wikipedia's article about the Kármán line is an interpretation, not the definition ! Why not consider the Kármán line as a curved boundary that ...
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70 votes
17 answers
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### Why is using a space elevator cheaper than rocket power?

Why is rocket power so much less efficient? In both cases you want to lift a given weight a certain height. What does climbing a tether give you that you don't have when using rockets? Wouldn't a ...
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### What would a "Kármán plane" look like, a bird, or a plane?

If I understand correctly (which I might not), the Kármán line is roughly the altitude where a "Kármán plane's" upward lift force at the orbital velocity for that altitude would be equal in magnitude ...
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9 votes
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### Grid Fin lift to drag ratio

For a Grid Fin, what would be the most optimal way of finding the lift to drag ratio? I am thinking about comparing lift to drag ratios of square lattice Grid Fins but with different geometrical ...
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### Modeling SpaceX's lift and drag versus angle of attack and Mach number

I've been trying to find data in the literature that would provide analytical expressions for the relationship between the lift and drag of an object similar in shape and size to the Falcon 9 first-...
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10 votes
4 answers
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### Challenging the Kármán line from above

The initial conditions of the thought experiment is (very) LEO / reentry. capsules, space shuttle and other spacecraft can generate lift in upper atmosphere during reentry, in order to reduce ...
9 votes
1 answer
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### Just how much can tall skinny rockets bend? (roughly, safely)

Below is a GIF I prepared and used in an earlier question, and the answer seems quite reasonable. With a height to diameter ratio of about 70 m to 3.7 m (nearly 20:1) a weight-conscious design, ...
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2 votes
2 answers
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### Rocket drag and lift based on flight direction - in which frame of reference?

Drag is aerodynamic force component parallel to the direction of motion. Lift is aerodynamic force component perpendicular to the direction of motion. Direction of motion with respect to what? 1) ...
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7 votes
4 answers
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### Is aerodynamic lift ever useful in rocket flight?

When a rocket is traveling through an atmosphere, the component of the aerodynamic force in the direction of motion is called drag, and the component perpendicular to that is called lift. Usually a ...
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11 votes
2 answers
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### Would an ionocraft have better or worse performance in the upper atmosphere?

The ionocraft produces lift by accelerating ions in the air downward by the use of two meshes held at a large relative voltage difference. With a cursory look at the physical principle, it seems like ...
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