What is the total lift for a fixed wing plane and helicopter?

In summary: This is because the propeller creates drag, whereas the rotary wing bypasses the propeller's drag and actually generates lift.
  • #1
KuriousKid
48
0
I came to know that Fixed wing as well as propeller lift equations are same [Am I right]?

Anyways I have question.

What's total lift for fixed wing plane with Wing length of 4 m, 1 m width, Angle of attack = 16 degree, and Wind/plane speed of 6 m/s?

Secondly, what's total lift for Helicopter with propeller diameter of 4 m, width of 1 m and Rpm of 420? Considering angle of attack = 16 degrees?

Any one care to explain in detail?

Surely, I will have follow up questions but let's divide and conquer :)
 
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  • #2
It also depends on the air properties and the airfoil shape...
 
  • #3
This is a difficult question to answer. Like russ said it depends on airfoil shape but it will also depend on whether or not certain parts of the wing are stalled. For a wing with a chord of 1m and velocity of 6m/s in air the Reynolds number is approximately 380000 which is pretty low. At this low Reynolds number and and angle of attack of 16 degrees there will almost certainly be regions of separated flow over the wing. The entire wing may even be stalled.

For a wing, the easiest way to get an estimate of the lift is lifting line theory. Unfortunately LLT assumes the flow is inviscid, which is a poor assumption in your case since there will be regions of separated flow. However it is possible to get decent estimates with this method by using experimental data for the airfoil as opposed to the thin airfoil theory result which determines the sectional lift coefficient assuming inviscid flow.
 
  • #4
Thank you for your replies. Let's consider it's quite air. Air Not flowing, but wings are in speed. No stalling. Wings are in perfect or ideal shape for max lift.

I'm just setting hypothetical envioronment saying everything is ideal as it should be :)

Second question for wing's width in both cases. Having more width at lower speed is'nt benefitial (contributing factor) for more lift?
 
  • #5
If you want an upper bound on your lift the easiest thing to do would be to treat your wing as an airfoil and then use thin airfoil theory.
 
  • #6
What would be equation in either case for Thin Foil Theory?
 
  • #7
KuriousKid said:
What would be equation in either case for Thin Foil Theory?

There is no standard equation for lift or any sort of general case for any sort of aerodynamic force. The situation is much more complicated than that.
 
  • #8
One simple observation: A helicopter's lift is generated by its "Rotary Wing", and NOT its propeller.
 

1. How does an airplane stay in the air?

An airplane stays in the air due to the principle of lift. The wings of an airplane are designed to create an area of low pressure above the wing and high pressure below the wing. This pressure difference creates an upward force called lift, which allows the airplane to stay in the air.

2. What factors affect the lift of an airplane?

The amount of lift an airplane generates depends on several factors, including the shape and size of the wings, the speed of the aircraft, and the angle of attack (the angle between the wing and the incoming air). Other factors that can affect lift include air density, air temperature, and airfoil design.

3. How do helicopters generate lift?

Unlike airplanes, which use wings to generate lift, helicopters use rotating blades to create lift. As the blades spin, they create a difference in air pressure above and below the blades, which produces lift. The angle of the blades can also be adjusted to increase or decrease lift as needed.

4. Can airplanes and helicopters fly in the same way?

No, airplanes and helicopters use different methods to generate lift and fly. Airplanes rely on their wings to generate lift and require forward motion to stay in the air, while helicopters use rotating blades and can hover in place.

5. How does altitude affect lift?

As an airplane or helicopter gains altitude, the air becomes thinner and less dense. This can affect the amount of lift generated, so pilots must make adjustments to maintain the desired amount of lift. In general, the higher the altitude, the lower the lift, which is why airplanes have maximum operating altitudes.

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