Question 4.19: Let us assume that for our previous example (Example 4.17) 1...

Aircraft Engineering Principles

Let us assume that for our previous example (Example 4.17) 1000 kg of cargo (item 2) is removed from the forward freight bay at a transit airfield. Our problem is to calculate the new CG position.

The blue check mark means that this solution has been answered and checked by an expert. This guarantees that the final answer is accurate.
Learn more on how we answer questions.

From our original calculations:

Total mass of aircraft	= 46,700 kg
Total moment for aircraft	= 652,900 kgm
Cargo removed	= 1000 kg
Moment for cargo removed	= (−1000)(5)
	= 5000 kgm
New total mass for aircraft	= 46,700 − 1000
	= 45,700 kg
New moment for aircraft	= 652,900 − 5000
	= 647,900 kgm

So new position of CG from datum

$=\frac{647,900 \ kgm }{45,700 \ kg }=14.18 \ m$

It is important to remember that if any single mass is altered, this will alter the total mass and the total mass moment of the aircraft.

Related Answered Questions

Question: 4.25

1. The mass airflow through a propeller is 400 kg/s. If the inlet velocity is 0 m/s and the outlet velocity is 50 m/s, what thrust is developed? 2. Assume that the mass airflow through a gas turbine engine is 40 kg/s. If the inlet velocity is 0 m/s and the exhaust jet velocity is 500 m/s, what ...

Verified Answer:

We use the simplified version of the thrust equati...

Question: 4.46

Taking atmospheric pressure as 101,320 N/m², convert the following gauge pressures into absolute pressure (give your answer in kN/m² or kPa): (a) 400 kN/m², (b) 20 MN/m², (c) 5000 Pa and (d) 3000 psi. ...

Verified Answer:

We know from above that absolute pressure is equal...

Question: 4.5

Convert (a) 450 knots into kph and (b) 120 m/s into mph. ...

Verified Answer:

We could simply multiply by the relevant conversio...

Question: 4.8

Three coplanar forces (forces that act within the same plane) –A, B and C – are all applied to a pin joint (Figure 4.16(a)). Determine the magnitude and direction of the equilibrant for the system. ...

Verified Answer:

Each force needs to be resolved into its two ortho...

Question: 4.53

A steel bar has a length of 4.0 m at 10°C. What will be the length of the bar when it is heated to 350°C? If a sphere of diameter 15 cm is made from the same material, what will be the percentage increase in surface area if the sphere is subject to the same initial and final temperatures? ...

Verified Answer:

Using

\alpha=12 \times 10^{-6}

from...

Question: 4.54

How much thermal energy is required to raise the temperature of 5 kg of aluminium from 20 to 40°C? Take the specific heat capacity for aluminium as 900 J/kgK. ...

Verified Answer:

All that is required is to substitute the appropri...

Question: 4.55

0.22 kg of gas at a temperature of 20°C and pressure of 103 kN/m² occupies a volume of 0.18 m³. If the cv for the gas = 720 J/kgK, find (a) the characteristic gas constant and (b) the specific heat capacity at constant pressure. ...

Verified Answer:

a) Using pV = mRT, on re-arrangement,

...

Question: 4.56

1. How much heat energy is required to change 3 kg of ice at 0°C into water at 30°C? 2. What thermal energy is required to condense 0.2 kg of steam into water at 100°C? ...

Verified Answer:

1. The thermal energy required to convert ice...

Question: 4.57

During a non-flow thermodynamic process the internal energy possessed by the working fluid within the system was increased from 10 to 30 kJ while 40 kJ of work was done by the system. What are the magnitude and direction of the heat energy transfer across the system during the process? ...

Verified Answer:

Using Q − W =

U_2 - U_1

, where [lat...

Question: 4.58

At entry to a horizontal steady flow system, the fluid has a specific enthalpy of 2000 kJ/kg and possesses 250 kJ/kg of KE. At the outlet from the system, the specific enthalpy is 1200 kJ/kg and there is negligible KE. If there is no heat energy transfer during the process, determine the magnitude ...

Verified Answer:

Using the above SFEE equation, we first note that ...