Explanation Given information: The maximum downward air speed ( v ) is 80 ft / s . The diameter ( d ) of the slipstream is 30 ft . Total weight of the helicopter and the crew, W is 3 , 500 lb . The specific weight of air γ is 0.076 lb / ft 3 . Calculation: Sketch the free body diagram of slipstream as shown in Figure 1. Find the mass flow rate ( d m d t ) using the Equation as follows: mass = density × volume = density × ( area × length ) Δ m = ρ A B ( Δ l ) (1) Substitute ( v B × Δ t ) for Δ l in Equation (1). Δ m = ρ A B v B ( Δ t ) Δ m Δ t = ρ A B v B Δ m Δ t = γ g A B v B d m d t = γ g A B v B (2) Here, A B is area of the slipstream well below the helicopter and v B is the corresponding velocity in the slipstream. Substitute ρ for γ g in Equation (2). d m d t = ρ A B v B Find the thrust ( F ) on the helicopter using the relation as follows: F = d m d t ( v B − v A ) (3) Here, v A is located at top of the blade. Thus, the v A is zero. Substitute γ g A B v B for d m d t in Equation (3)

12th Edition

ISBN: 9781260265453

Author: BEER

Publisher: MCG

See similar textbooks

Concept explainers

Conservation of Energy

In physics, the rule of the conservation of energy states that energy doesn’t disappear from the atmosphere; instead, it changes its form from one type to another. Energy is one of the most important physical quantities in nature, and it cannot be create…

Videos

Question

Chapter 14.3, Problem 14.72P

To determine

Find the maximum load such that helicopter can lift while hovering in mid-air.

Expert Solution & Answer

Want to see the full answer?

Check out a sample textbook solution

See solution

Chapter 14.3, Problem 14.71P

Chapter 14.3, Problem 14.73P

Students have asked these similar questions

The helicopter shown can produce a maximum downward air speed of 80 ft/s in a 30-ft-diameter slipstream. Knowing that the weight of the helicopter and its crew is 3500 lb and assuming y= 0.076 lb/ft3 for air, determine the maximum load that the helicopter can lift while hovering in midair.

The total drag due to air friction on a jet airplane traveling at 900 km/h is 35 kN. Knowing that the exhaust velocity is 600 m/s relative to the airplane, determine the mass of air that must pass through the engine per second to maintain the speed of 900 km/h in level flight.

Q3/ PROBLEM 12.24 An airplane has a mass of 25 Mg and its engines develop a total thrust of 40 kN during take-off. If the drag D exerted on the plane has a magnitude D = 2.25v, where v is expressed in meters per second andD in newtons, and if the plane becomes airbone at a speed of 240 km/h, determine the length of runway required for the plane to take off.

Chapter 14 Solutions

VECTOR MECH...,STAT.+DYN.(LL)-W/ACCESS

Ch. 14.1 - A 30-g bullet is fired with a horizontal velocity...Ch. 14.1 - Two identical 1350-kg automobiles A and B are at...Ch. 14.1 - An airline employee tosses two suitcases in rapid...Ch. 14.1 - Car A weighing 4000 lb and car B weighing 3700 lb...Ch. 14.1 - Two swimmers A and B, of weight 190 lb and 125 lb,...Ch. 14.1 - A 180-lb man and a 120-lb woman stand side by side...Ch. 14.1 - A 40-Mg boxcar A is moving in a railroad...Ch. 14.1 - Two identical cars A and B are at rest on a...Ch. 14.1 - A 20-kg base satellite deploys three...Ch. 14.1 - For the satellite system of Prob. 14.9, assuming...

Knowledge Booster

Learn more about

Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.

Find the maximum load such that helicopter can lift while hovering in mid-air.

Solution Summary: The author calculates the maximum load such that helicopter can lift while hovering in mid-air using the Equation as follows:

Concept explainers

Videos

Find the maximum load such that helicopter can lift while hovering in mid-air.

Want to see the full answer?

Chapter 14 Solutions