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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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The physics of flight

Physics in schools teaches two contradictory and mutually exclusive things: (1) 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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How are the weights of sumo wrestlers shown on the load&trimsheet form? [duplicate]

Under normal circumstances most airlines use standard weights to calculate passenger weights. Sometimes, passenger groups with different weight than the normal passenger profile can also travel. How ...
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Trying to find the vertical speed from substituting weight from lift

I'm trying to determine the vertical 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 Lift ...
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What is 737-8 cg range

How does the Boeing 737MAX-8 CG range in percent mac compare with other Boeing airplanes? Forward cg is more stable but more difficult to control. Does the FAA require a certain cg range? Adding the "...
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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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1answer
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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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1answer
634 views

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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1answer
197 views

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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2answers
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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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1answer
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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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1answer
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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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2answers
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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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1answer
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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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2answers
596 views

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 ...
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2answers
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Does object mass have a significant bearing on wind interference?

I'm learning to fly RC quadcopters, and before I go outside with an expensive, possibly dangerous (if it were out of control and hit something) large unit, I've decided to practice flying for a while ...
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Why are “counterweights” used in aircraft production?

From this question, manufacturers use "counterweight" or "ballast" when producing aircraft. Why is the use of weight necessary? Supposedly aircraft should be made as light as possible, and ...
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What is the reasoning behind using depleted uranium as counterweights in the 747?

I recently found out that some of the earlier models of 747 had between 600 and 1100lbs of depleted uranium as counterweights. These counterweights were found in 747s manufactured between 1968 and ...
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How has weight been reduced in commercial aircraft design and how will this trend continue?

Reducing weight of aircraft has become a priority as the aviation industry seeks greater fuel efficiency and commits to strict emissions targets. How much weight has been cut from single and twin ...
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3answers
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What are the physical laws for upscaling an RC model to 1:1?

What are the laws of physics for upscaling an RC model from a smaller to larger scale or even to a full sized 1:1 aircraft? I guess the basic thing may be lift/weight ratio which was nicely described ...
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1answer
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What is the significance of the 10,600 lbs MTOW limit?

I recently noticed that several airplanes have MTOWs very near or exactly 10,600 lbs. That was an interesting phenomenon to me because I am familiar with the 12,500 lbs MTOW regulatory limit on ...
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1answer
856 views

Is V(L/D)max equivalent to glide speed regardless of weight, engine, height, etc.?

I've read Carson's paper on V(L/D)max, and while theoretically interesting, it does not seem to me to be useful in actually finding the V(L/D)max of an arbitrary aircraft, as it assumes knowledge of ...
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1answer
463 views

What is the difference between landing weight and end-of-mission weight?

Raymer says: Landing is much like taking off, only backwards!....Note that the aircraft weight for landing analysis is specified in the design requirements, and ranges from the takeoff value to ...
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5answers
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What happens during a powered descent?

I was having a discussion with my friend about equilibrium condition in flight: Scenario: While going in straight and level flight, say I reduced my airspeed by 30 mph. At the same time keeping the ...
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4answers
657 views

Is an aircraft's maximum landing weight really weight, or is it mass?

I'm calculating the lift of a Cessna 172 and I don't understand the numbers given for weight. The maximum landing weight is 2550 pounds which is nearly 1134kg. But does that mean 1134 Newtons (weight) ...
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Which part of aircraft is contributing the most weight of airplane?

Which part of the aircraft contributes the highest portion of weight? Note: we had argument that, wires connecting the avionics systems are the major contributors of aircraft weight. Due to some ...
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1answer
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How do I calculate aircraft range with these parameters?

The parameters are: MTOW, MLW, MZFW, OEW, maximum fuel weight, fuel flow rate and true airspeed. Measured in lbs and kts. Not given drag so unsure how to apply Breguet equation. Trying to construct a ...
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What are the concerns and consequences of an overweight landing?

If a 777 ER has to immediately land after takeoff on a planned 14,594 km trip (in the case of a fire, e.g.), the landing will be executed with a very heavy aircraft. What are the major concerns of ...
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How heavy are the Boeing 747 landing gear?

Does anyone know how heavy are the combined landing gear on a Boeing 747? It would be interesting if someone has also weight statistics per gear (nose gear and the four other main gear).