Questions tagged [aircraft-physics]

Physics as they apply to aircraft. Including aerodynamics, flight dynamics, stability and control, aircraft hydraulic and electric systems, engine thermodynamics.

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Has there ever been a VTOL aircraft thruster that generated lift through the use of a drag force?

I have been recently thinking about a conceptual VTOL aircraft thruster that should generate lift through the use of a drag force and I am very curious to know if such a thruster has ever been built ...
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1 vote
1 answer
49 views

When using momentum theory for estimating power needed to hover, is propulsive efficiency accounted for?

I am using momentum theory to estimate power needed for an eVTOL. I have read past papers where the results got from momentum theory was direcly use to estimate the power needed from the battery. How ...
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3 votes
1 answer
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Could the Wright Flyer II takeoff without wind?

The Wright Flyer II could reach about 20 mph of airspeed on the track alone. The aircraft needed an airspeed of about 30 mph to make a proper takeoff (without hanging in ground effect). Before the ...
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2 answers
165 views

Which one produces more lift?

I have come across this question on Twitter. I have found a similar question here. The aircraft isn't flying but just doing Cobra Maneuver. Since the direction of the lift is in the same direction and ...
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6 answers
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What is the name of the effect that causes a plane in a dive to go up?

What's the name of the effect that causes the aircraft to automatically pull out of a dive and buffet up due to aerodynamic lift produced at high speeds?
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4 answers
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How can ground speed be higher than airspeed? [duplicate]

I've heard that ground speed is higher than air speed when the plane is being pushed by wind wind. But how is this possible? Wouldn't your AirSpeed also increase since you're going faster?
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Is there an equation for how fast air accelerates into lower-pressure regions?

I’m designing a propeller, and I want to plan the shape of the trailing edge of each blade such that (as much as reasonably possible) the pressure comes out as an “equal” line. Thus - I'm wondering ...
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2 votes
1 answer
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Why do transport-category aircraft have hard tailwind limitations?

With most transport-category aircraft, even with a 5 km runway, gross weight close to ZFW, using maximum flaps for takeoff, performing an unpressurized, full-power takeoff, the maximum legal tailwind ...
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2 answers
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Is Vbg maximum Lift/Drag ratio, or is it really maximum Speed/Drag ratio?

A question about "minimum power" airspeed had me wondering, why not think of "maximum Lift/Drag ratio" as maximum Lift/Thrust ratio. Gliders would be included, as they use gravity ...
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3 votes
1 answer
79 views

How to calculate the inaccuracy in the "standard" turn radius equation, for supersonic airspeeds

I learned to calculate the radius of a level turn (r) using the function $ r = \frac{V^2} {g . tan(bank angle)}$. V is true airspeed, g is the local gravity constant. But now I have seen in the ...
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Are Airbus A320 Cabin Door Exterior & Interior Levers Linked?

Was looking at this video on Airbus A320 Cabin door procedures and was wondering if the exterior door lever is mechanically linked to the interior lever? It seems as if the exterior lever will open ...
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How does the velocity of a turboprop engine relative to the airplane change when a plane is banking?

I saw this YouTube video recently: And in it, a turboprop engine propeller and gearbox comes out and slashes across the underbelly of the plane, crippling the aircraft....
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1 vote
3 answers
207 views

Why does power go up with the cube of the airspeed?

If i have an airplane with over 100 kN of thrust, and i want to accelerate from a velocity at which drag force is 25kN to a velocity twice higher, is it possible that i wont be able to do this because ...
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Calculate Rudder Angle by Bank Angle [closed]

My question: Is rudder angle equal to bank angle? Or, does rudder angle has some relationship with ROT formula? Below is my steps trying to solve this question. Step 1: Found below graph from this ...
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3 answers
202 views

Calculate speed by turn angle and distance [closed]

I'm trying to combine two rate of turn formulas, which I found it online this and this. The first is ROT = 1091 * tan(bank angle) / speed in knots The second is <...
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4 votes
1 answer
188 views

Can a jet-engine aircraft fly all the way to its service ceiling at its maximum takeoff weight? [closed]

I am trying to understand how high an aircraft can get to at its maximum takeoff weight (minus whatever fuel is consumed in getting to that altitude). Can it make it all the way to its service ceiling?...
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5 votes
3 answers
675 views

Is it realistic that a plane reacts very quickly to rudder input as shown in a MSFS video?

Microsoft Flight Simulator is supposed to be a "simulator", so following the laws of physics. However, I'm looking at a gameplay video (at 2:17) and it shows a plane reacting really quickly ...
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Can a fixed pitch propeller be designed to act as both a propeller and a generator?

The angle of attack (AoA) plays a major role in designing a propeller for specific uses, such as if it is to be designed for aircraft propulsion the AoA must be high, while the AoA must be low if it ...
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-1 votes
1 answer
128 views

What are the feasibility of making a spherical aircraft using Magnus/Coanda Effect? [closed]

Well, I'm quite ignorant in aerodynamics in general, but I couldn't find any aircraft that fits this description. And yes, I know that wouldn't be as efficient as a conventional aircraft, but I'm ...
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7 votes
2 answers
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G Load during payload drop

Some days ago I saw the accident of the airtractor that, just after a drop, suffered a spar failure in both the wings. Luckily the pilot survived. If load factor in his simplest formula is: n=lift/...
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6 votes
1 answer
164 views

What are the wake turbulence characteristics at ground level near landing aircraft?

I'm a structural engineer and I need to understand the additional forces that wake turbulence may cause on a building near a runway. I can determine the natural wind speed and associated forces on the ...
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5 votes
2 answers
947 views

Can the energy dissipated in a power-off descent be calculated and expressed in horsepower?

If the weight in pounds of an aircraft is known along with its sink rate in feet per minute at best power-off glide conditions, can the horsepower being dissipated by drag as the plane descends via ...
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0 votes
1 answer
226 views

How to calculate the takeoff speed for a hypothetical aircraft?

Given some basic information such as: aircraft weight wing load (including wingspan, and basically the whole wing configuration) airfoil profile coefficient of lift angle of attack Is it possible to ...
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2 votes
3 answers
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Can you have a Hybrid Turboprop-Jet engine?

To start things off I am writing this to gain information for vehicles in a story, so I am more so looking for theoretical possibilities, unless there are real world examples. The background and my ...
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2 answers
152 views

Can aileron control maintain track in a single engine failure on a twin?

Let us say I am flying a twin-engine aircraft and I got a engine failure during cruise, without any control on rudder and use the ailerons only, can I still maintain the target track or heading? Will ...
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2 votes
1 answer
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Are the gyroscopic precession and P-factor of a pusher propeller in opposite directions?

according to this picture the P factor cuases airplane to yaw to the right but if pilot wants to pitch up , then p factor and gyroscopic precession acts on airplane at the same time but in opposite ...
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2 votes
0 answers
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Streamline Curvature Theorem applied to Airfoils?

I am new to studying aerodynamics and taking up aeromodelling and am currently learning how lift is obtained in-depth. When studying the two common explanations as to how lift is generated by an ...
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2 votes
1 answer
188 views

Do pusher propellers create the same yawing moment as puller propellers? [closed]

We know that the effect of P-factor on puller propellers is the yawing moment in the opposite direction. I mean if we had a load (thrust or lift) on the right side of propeller, then the airplane will ...
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10 votes
6 answers
6k views

Why do planes fly at a high angle of attack when flying slow?

I've noticed that when a plane does slow flight, the pilot increases the angle of attack (AOA). What is the purpose of this? F-18 - Slow Pass
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0 votes
3 answers
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How does bypass air work?

As far as I’m aware, high-bypass engines have far higher fuel efficiency than low-bypass engines, and as a result the effective specific impulse of the engine is increased. What I’m trying to figure ...
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16 votes
5 answers
3k views

Why is thrust inverse to speed in piston engines?

It is said that piston engines have constant power output, and thus their thrust is inverse to speed (e.g. here), while turbines have relatively constant thrust. I'm looking for an intuitive ...
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1 answer
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If aircraft specific energy is a combination of kinetic and potential energy, why is altitude not a variable in the energy-maneuverability theory? [closed]

The Energy-Manueverability formula is $$ P_S = V \left( \frac{T - D}{W} \right) $$ with velocity $V$, thrust $T$, drag $D$ and weight $W$. $P_s$ represents specific energy, which is a combination of ...
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1 vote
2 answers
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How to fly a quick return to origin after takeoff

If I want the shortest traffic pattern to play touch and go or I got a emergency right after liftoff but the engine is still working, I just want to get back to ground as soon as possible, what is the ...
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2 votes
5 answers
282 views

Relationship between hover power and climbing power

I've been told that, generally speaking, rotor efficiency increase with rotor diameter. This is because the thrust generated by a helicopter rotor equals the mass of air moved times the delta V of the ...
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7 votes
2 answers
481 views

How much does the fuselage of an airplane contribute to yaw stabilization?

Obviously considering that (almost) every plane has a vertical stabilizer, probably not, but for a relatively long aircraft does the fuselage measurably contribute to the yaw stabilization relative to ...
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3 votes
4 answers
708 views

What is maximum acceleration that can be achieved by afterburner in level flight?

I am wondering how a fighter jet (let's take F-22 for example) would compare to other vehicles in terms of acceleration while in flight. For cars and motorcycles, achieving 0-100 KPH in 2 seconds is ...
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2 votes
4 answers
211 views

Which way to turn to return to runway for downwind landing-- into crosswind or with crosswind?

The scenario-- you are taking off with a significant headwind component but also a significant crosswind component. You experience a power loss (or perhaps a tow rope break in a glider). You judge ...
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5 votes
4 answers
438 views

Is the total upwards vertical force (lift included) greater than the weight in a steady climb?

Related to questions on forces in a climb: if any aircraft is climbing with a constant velocity, is the total upwards vertical force (lift included) greater than the weight?
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0 answers
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Does a fighter aircraft slow down when firing machine guns? [duplicate]

I imagine the recoil of a powerful machine gun or cannon would decelerate a plane significantly. Is this an issue?
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1 vote
2 answers
926 views

Center of Gravity and Center of Lift stability

I have recently been reading about the center of gravity and center of lift. On the German Wikipedia there are many different graphics about the relation between the center of gravity and the center ...
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-2 votes
3 answers
252 views

Is lift less in a steeper descent than in a shallower descent, and if so, by how much?

Is lift less in a steeper descent than in a shallower descent, and if so, by how much? For example, if we change our ratio of horizontal distance travelled to vertical distance travelled (through the ...
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-6 votes
1 answer
146 views

Would mid-air refueling for an air-to-space vehicle that flies like a plane be a viable advantage if the tech was available? [closed]

Let's take the style of an F-22 Raptor (awesome!), build the fuselage, wings, etc to handle runway takeoff horizontally and then vertically (if needed) up to orbital space flight to reach the ISS in ...
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3 votes
1 answer
130 views

How can one change the wingtip geometry to enhance the wingtip vortices?

I'm doing some research on enhancing wingtip vortices as part of my Honours project. After spending a fair bit of time in the literature and on this forum I have some models which should kick-start my ...
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7 votes
6 answers
2k views

Is a trimmed flight not always an unstable system?

As soon as I am flying in trimmed flight condition, my pitching moment around the center of gravity becomes zero. So my center of pressure has to be located in the center of gravity, so that there is ...
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2 votes
4 answers
567 views

Engine out over a mountain road. Do you land upwind or up hill?

You're flying solo in a late-model, fixed-gear Cessna 172 with half-full fuel tanks. You are at 1000 feet AGL, 100 knots indicated, directly above the middle of a 2000 foot long straight section of ...
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4 votes
2 answers
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In this F-104 V-n diagram, why does the stall speed (in terms of IAS) decrease with altitude in some parts of the flight envelope?

(This question has been edited to reflect a change in perspective: based on answers to the related question What is causing these "corners" on this F-104 V-n diagram?, I now believe that the ...
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8 votes
1 answer
492 views

What is causing these "corners" on this F-104 V-n diagram?

In this V-n diagram for an F-104 (source: this Wikipedia link), on the left-hand edge of the flight envelope, what is causing the "corners" that we see at the following points? (Numbers are ...
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1 vote
5 answers
488 views

What causes the ball to not be centered in a slip/skid?

I've reviewed quite a few questions on this forum including Forces in a slipping turn is-this-vector-diagram-of-the-forces-at-play-in-turning-flight-correct what-does-the-balance-ball-actually-...
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2 votes
1 answer
164 views

How does airfoil affect the coefficient of lift vs. AOA slope?

I'm trying to understand whether the airfoil shape can affect the slope of Cl vs. AOA (coefficient of lift vs. angle of attack) in the "linear" portion, e.g., from a few degrees negative to ...
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1 vote
2 answers
144 views

Why is this equation for TAS only valid for subsonic flow?

I came across the equation for calculating True airspeed (TAS) on Wikipedia: $$ \text{TAS} = a_0 \sqrt{\frac{5 T}{T_0} \left[ \left( \frac{q_c}{P} + 1 \right)^{2 / 7} - 1 \right]} $$ But this equation ...
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