Questions tagged [weight]

In science and engineering, the weight of an object is usually taken to be the force on the object due to gravity. Weight is a vector whose magnitude (a scalar quantity), often denoted by an italic letter W, is the product of the mass m of the object and the magnitude of the local gravitational acceleration g; thus: W = mg. The unit of measurement for weight is that of force, which in the International System of Units (SI) is the newton.

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How can I calculate the minimum thrust to weight ratio required for a given takeoff distance?

I am building a plane and I have a take-off distance of 50ft, is there a way for me to estimate the thrust-to-weight ratio required for this constraint (even if it was in terms of say wing loading)?
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Does the center of lift have to be in line with the center of mass?

Imagine 2 theoretical planes, A and B, shown in the image below. The center of mass is yellow, and the center of lift is blue. Would plane A and plane B work as well as an airplane with the center of ...
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What do we mean by taking the lowest of ZFW; TOW and LW to determine the maximum takeoff weight of the day?

Firstly, I understand that the maximum permissible takeoff weight can be limited by landing weight because landing weight plus trip fuel gives us one take off weight. We obviously do not want to be ...
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How much aluminum was used in the Boeing 727?

What is the weight of aluminum used in the Boeing 727 fuselage? Do you know where I can find it? Any manual or site or something like that?
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How fixed air, gas and fixed weights in rigid airships is computed in this book?

I hope I am posting this in the right forum. My current problem is part aviation, part maths. I have been struggling with the following computation ( Burgess, Charles Paine. Airship Design. Honolulu, ...
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Are General Aviation tires filled with Nitrogen?

Long story short, I'm working on a concept for a book. We all know why commercial aircraft have nitrogen tires, but my question is if GA aircraft have nitrogen tires, or are they just filled with ...
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Why does the mass penalty of cantilever vs externally braced wing decrease with aircraft size?

From Wikipedia Cantilever wings require a much heavier spar than would otherwise be needed in cable-stayed designs. However, as the size of an aircraft increases, the additional weight penalty ...
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For electric aircraft, is MTOW = Empty weight + Maximum payload?

Electric aircrafts and most drones have simple powertrains, and their weight does not vary along the flight. After reviewing this thread I assume that: MTOW = Empty weight (batteries incl) + max ...
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Why does increasing a glider's weight using water ballast improve its speed and performance? [duplicate]

I was studying gliders and how they fly. There is a point that's not clear to me: why does using water ballast improve the performance/speed of a glider? If I understand correctly, my glider jumps ...
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How to calculate bending moments and shear forces on a wing?

I am trying to create a MATLAB script to plot the Bending Moment Diagram (BMD) and Shear Force Diagram (SFD) as a function of spanwise distance, x, along a wing from the wing root (x=0) to the wingtip ...
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Are there any airliners capable of vertical climb with engine thrust only by pointing the nose up?

So, sort of inspired by this question, I was wondering if there were any passenger airliners with enough thrust to fly straight up, supported purely through the thrust of their engines rather than the ...
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Average weight of fuel required to carry 1Kg additional cargo weight per hour [duplicate]

I'm looking for an average number here, I know there is not one correct answer as there are many parameters to take into account. Alternatively, I could also use something different, like : how many ...
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MTOW Calculation with Roskam Wempty and MTOW corellation

I'm an aerospace engineer and as a semester project, I've been assigned to do a conceptual design of a wide-body passenger aircraft(320 PAX, 9500 NM, M=0.89). Our handbook uses Roskam's equation, ...
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Do airline dispatchers pre-block seats for weight and balance on large wide body aircraft?

I was reading a Oman Air flight review and one of the bits intrigued me: I had earlier used ExpertFlyer to monitor both how busy the flight would be and the seat map. I selected a window seat ...
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How is the impact force on the landing gear distributed in fighters?

Upon landing, what percentage of weight is distributed on the main and the nose landing gears of fighters? Upon landing of a fighter aircraft, what would be the approximate time of transfer of the ...
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What adds more weight to a twinjet? Tail-engines or wing-engines?

Let's say we have a large commercial jet, with exactly 2 engines, capable of holding at least 200 passengers. It could be a traditional jet like the Boeing 777, where both engines are in the wing. Or ...
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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 ...
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Can the removal of a duty-free sales trolley result in a measurable reduction in emissions?

Recently, SAS announced that: Withdrawing tax-free sales will reduce the overall weight of the aircraft, which in turn will reduce fuel consumption and emissions. I could buy that this might be a ...
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Trying to find the vertical acceleration by subtracting weight from lift

I'm trying to determine the vertical acceleration component of a plane with the following specifications: Density of air: 1.29kg/m3 Speed: 33 m/s Wing area: 13.97 m2 Lift Coefficient: 1.5 Mass:560 kg ...
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Why does the DC-8-70 have the same MTOW as the DC-8-60, despite its more powerful engines?

The DC-8-70 is a more-or-less straight reengine of the DC-8-601, replacing the obsolete JT3D-3B low-bypass turbofans of the DC-8-60 with the CFM56-2C1 high-bypass turbofan. According to Wikipedia, ...
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Would knowing the exact weight that has been loaded on a commercial plane and it's distribution be useful? [duplicate]

There's been a bit in the media about weighing passengers in order to get more accurate take off weights for commercial planes. I'm guessing the delta between a heavy set of passengers and a light ...
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What is the weight of the fuselage (only) of the Boeing 747?

I'm wondering about the weight of the Boeing 747's fuselage.
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How long will an aircraft need to fly before it can land without dumping fuel? [closed]

Now, I know perfectly well that the literal and unhelpful answer to the question is long enough to burn sufficient fuel that it is no longer overweight for landing. What I'd like to understand is ...
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How does wind affect takeoff weight limits?

Two days ago I took off from BUR in relatively windy (although dry) conditions. Flightradar showed departure from runway 33, and winds were recorded roughly mid 20s kts from the N-NNE direction. ...
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What are (wing area)/(weight) ratio in birds and airplanes? [closed]

I like to know the usual ratio of wing area over weight in birds and airplanes? I mean if total weight of an airplane is 100 Lbs(Kg), how much should be the least ...
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How do airlines handle their non-standard passengers for the load control process? [duplicate]

How are non-standard passenger weights maintained in the systems? How they do they handle these passenger weights between check in and load control system and etc..
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What are the B737 MAX 8's OEW and max payload?

I have Googled it, but have not found official info on that.
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Does Raymer's installed engine equation include the weight of the pylon?

I am currently modelling an aero engine and require the weight breakdown of the individual components, I have the dry weight of the engine and need to verify the pylon and nacelle weight. Raymer has ...
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How to calculate the amount of weight my plane can takeoff with?

This is how I approached this problem- My takeoff run is limited. So, depending on my configuration I calculated the maximum possible velocity I can attain in my groundroll. I assumed that at the end ...
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Where to find information on weight breakdown for helicopters?

I would be interested in information on the weight breakdown for the different components of a helicopter. How much of the maximum gross weight is related to the airframe, engine, gearboxes, ...
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If airliners profit by moving luggage from checked to carry-on, why do some LCC gate-check luggage?

According to this answer, the less luggage is transported as checked luggage, the more "room" (in terms of weight) there is to bring along cargo, and thus more profit. At the same time, some LCCs ...
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How much does basecoat/clearcoat paint cost for an airline?

Suppose an airline with 15-20 A320 wanted to change the paint for the entire fleet, how much would it cost approximately? I need this for my thesis, but unfortunately, paint manufacturers I contacted ...
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Why are airlines so concerned with checked baggage weight?

Why is it that commercial airlines are so concerned with checked baggage weight, such that they charge extra just for the privilege of checking in a suitcase with a limited weight (e.g. 15kg), and ...
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How do I calculate new minimal speed for a glider when I put water into the tank?

Lets say a glider weights 400kg and has a minimal speed of 70km/h. When it has additionally 100l water, so in total 500kg, what is the new minimal speed? I would argue, that in order to reach the ...
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What is the maximum body weight allowed for a pilot?

What is the maximum allowed body weight for a new commercial pilot student? Would someone weighing 130kg be rejected on the basis of health? If so, what should that person weigh to avoid the ...
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How much extra weight is added by strengthening a piston-prop fighter for carrier landings?

To land on a carrier, an aircraft must be strong enough to withstand sudden deceleration by the tail hook catching the arresting wire. I think it also requires strengthening the undercarriage to ...
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How much water does a passenger airliner carry?

How is the amount of water for (a) toilet and (b) drinking to be carried by a flight calculated in the industry? Is there any formula or thumb rule using which we can roughly estimate the amount of ...
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What is the weight limit for a pilot to eject from an F-100?

What is the maximum weight for a pilot to use the ejection seat in an F-100 fighter?
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Would a lighter aircraft require the same amount of power than a heavier one to fly at the same speed?

I had a question come up: If aircraft A is identical to aircraft B, except that aircraft B weighs 200 kg more. Which of the following statements are true? The answer I selected was wrong: ...
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Why is the thrust/drag increase much lower at a lower FL with weight the only variable?

From and related to: What is the relation between drag and weight? Friction drag is not affected by the angle of attack change. The [induced] drag will increase with the square of the mass ...
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Where do I find the Weight Variants of an Airbus aircraft?

Where do I find the Weight Variants (WV) of an Airbus aircraft?
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Why do all airliners have life jackets?

According to this question, life jackets are not mandatory in planes that do not fly over large bodies of water. However, I have never been on an airline flight without life jackets (and the ...
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What is the average weight difference between composite and metal airliners?

Is there any rule of thumb for weight savings using composite materials. For example, is there an early model large airliner like the B747 or even B737 that later was modified with composite wings or ...
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Is there any way to estimate the weight difference between a trimmable horizontal stabilizer and a fixed tailplane?

I am trying to estimate the benefits of using a trimmable horizontal stabilizer (THS) instead of a fixed tailplane. In my model I use a T-tail (Sh~30 m), and I can trim the aicraft in every condition ...
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Why aren't there V-tail airliners?

Since a V-tail is lighter and generates less drag than a conventional empennage, why has this solution been put away from production?
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How does aircraft weight affect landing distance?

I am a private pilot. I posed a question to instructors in the flight school and got differing answers. For a given aircraft, landing at the same speed, with everything the same except for landing ...
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What is the largest aircraft (by max takeoff weight) in which all engines are in the tail?

The largest one I'm aware of is the Il-62, with a whopping 4 turbofans at its tail. Max takeoff weight is 165 tons. I actually don't care how many engines there are, as long as all are at the tail. I ...
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How large are the banners that are trailed behind small planes for advertising?

How large are the banners that are used for aerial advertising, and how much do they normally weigh? Example: source: © Raimond Spekking / CC BY-SA 4.0 (via Wikimedia Commons) Wikipedia page on ...
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Do you have to update weight and balance charts after installing new avionics?

The POH always has weight and balance charts. Let's say you install some new avionics, hence changing the weight of the aircraft. Do you need to update the POH binder with new weight & balance ...
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Free baggage allowance: Weight concept vs Piece concept? [closed]

What are the advantages of piece concept free baggage allowance policy compared to the weight concept free baggage allowance policy in terms of contribution to the profitability of a commercial ...