# Estimate Weight of Plane & Air Speed Above Wings

• mikefitz
In summary, we discussed the pressure difference of 525 Pa between the upper and lower surfaces of the wings of an airplane flying on a level path. We also determined the weight of the plane to be approximately 67200 N. For the second part of the question, we considered using Bernoulli's equation to estimate the air speed above the wings, but were unsure due to the lack of information provided.
mikefitz
An airplane flies on a level path. There is a pressure difference of 525 Pa between the lower and upper surfaces of the wings. The area of each wing surface is about 128 m2. The air moves below the wings at a speed of 81.5 m/s. Estimate (a) the weight of the plane and (b) the air speed above the wings.

Fup = PA
Fdown=mg

F=525*128=67200 N
67200 = m(9.81); m=6850.153kb

It weighs 67200 Newtons doesn't it?

also, I am unsure how to begin part b - any ideas? Thanks

for b u use bernoulli equation and throw the pressure to one side.u will notice that is P1 - P2 and that's ur 525 Pa

semc said:
for b u use bernoulli equation and throw the pressure to one side.u will notice that is P1 - P2 and that's ur 525 Pa

hmm, to use bernoulli's equation I need:

I don't have initial pressure, final pressure, the height, or any way to calculate V above the wings... I guess I'm unsure how to solve with so many unknowns??

any ideas? This one sure has me confused...

## 1. How do you estimate the weight of a plane?

To estimate the weight of a plane, you can use the formula W = m x g, where W is the weight, m is the mass, and g is the acceleration due to gravity (9.8 m/s²). The mass can be determined by weighing the plane on a scale or by adding up the weight of all the components.

## 2. What factors affect the weight of a plane?

The weight of a plane is affected by several factors, such as the materials used to build the plane, the size and design of the plane, the amount of fuel and cargo onboard, and the weight of the passengers and crew. The weight of a plane also changes during flight due to the consumption of fuel.

## 3. How does air speed above the wings affect the lift of a plane?

The air speed above the wings is crucial in generating lift for a plane. As the air flows over the curved shape of the wing, it creates an area of low pressure above the wing and high pressure below the wing. This pressure difference creates an upward force, or lift, which helps the plane to stay airborne.

## 4. Can a plane fly with zero air speed above the wings?

No, a plane cannot fly with zero air speed above the wings. The air speed is essential for generating lift, and without it, the plane would not be able to stay airborne. However, some planes, such as gliders, can stay airborne with minimal air speed due to their design and the use of rising air currents.

## 5. How is the air speed above the wings measured?

The air speed above the wings is typically measured using an instrument called an airspeed indicator. This instrument uses the difference between the static air pressure and the total air pressure to calculate the air speed. Other methods of measuring air speed include using GPS or radar systems.

Replies
6
Views
1K
Replies
2
Views
3K
Replies
12
Views
3K
Replies
4
Views
2K
Replies
4
Views
2K
Replies
2
Views
3K
Replies
2
Views
1K
Replies
2
Views
2K
Replies
4
Views
6K
Replies
2
Views
11K