# Questions tagged [cg]

The CG (Center of Gravity) of aircraft is the point at which the aircraft would balance if it were possible to suspend it at that point.

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### Is fuel in trim tank usable?

Some aircraft (A380, Concorde,...) are equipped with a trim tank in the tail. Transferring fuel from or to this tank help controlling the CG. This feature can only be achieved if there is fuel to ...
248 views

### What if all passengers move from one side to the other?

Given the question What happens when all passengers jump at once?, I wonder what would happen if they all moved from side to side. If all the passengers moved from the front to the tail, or the other ...
120 views

### Sensitivity of aircraft stability with respect to the CG location

I am working on the design of an aircraft (2 m long, wingspan = 3 m). The platform is longitudinally stable but it is very sensitive to the variation in CG location. For example, 1) CG_location = 100 ...
82 views

### How is the load & trimsheet form sent to ACARS?

After the last passengers and baggage are loaded onto the aircraft, the pilot in command is given a form called load & trimsheet which shows the passenger/baggage distributions, total weights and ...
478 views

### How are forward and aft CG limits calculated?

I have been tasked to create a POH for my aero engineering coursework and part of this task is to create the CG envelope for the theoretical 65 passenger aircraft. I have figured out weight, moment ...
242 views

### How to determine Center of Gravity of the airplane parts? [closed]

I am building a small-medium sized airplane. Is it possible to calculate "C.G" of each part of the airplane? If yes, How? Parts: Wings, Tail, Fuselage, Propeller(?)
624 views

### How to calculate the location of C.G. A.C. & N.P. in static longitudinal stability?

We are in the conceptual stage of design and, using Raymer & Nicolai as references, I am doing a rough calculation of "power off" neutral point (N.P.) to find the optimum c.g. and a.c. positions. ...
107 views

### How is proper CG maintained in ultralight pusher aircraft?

Considering pilot weight can vary 100lbs or more how do ultralight pusher airplanes maintain proper CG range?
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### Controllability vs. Stability in PHAK. Is it an error?

My understanding on the relationship between stability and controllability has been that greater stability means less controllability and vice versa. This post confirms that. However, I've came across ...
746 views

### Why is the top left corner cut off on the cg location envelope for small airplanes?

Why does the PA-28 C.G. envelope have the top left corner cut off rather than allowing higher weights at a forward C.G. like it does at the aft C.G.? (source)
4k views

### What is the weight that is used to balance an aircraft called?

I remember I was reading about balancing an airplane a few days ago, and i came across a type of weight that is added to balance the airplane. But, I do not remember what it was called. Also could ...
42k views

### What does %MAC mean?

A document said that the optimum CG position is from 13% MAC to 33% MAC. I'd like to know what that means, and what would this look like on an actual plane.
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### What is the Optimum center of mass location for an air-craft? [duplicate]

I was doing my mathematics exploration, and i would like to know what is the optimum center of mass location of a plane. Specifically, what would happen if the point were to be too close or too far ...
903 views

### Is the differential between the forward and aft CG limits indicative of the overall stability of an airplane?

Studying up on the Cessna 162 Skycatcher POH to take my checkride in soon and I noticed the differential between the maximum and minimum CG's is a mere 2.5 inches from one to another. I got curious ...
4k views

### Why is the AWACS' rotodome located at the back and over the aircraft?

Browsing this website, I found this question dealing with torque due to the huge piece in motion, and its answers also speak of drag. The rotodome is located above the aircraft and at the aft of the ...
3k views

### How Centre of Gravity (CG) is adjusted?

I've gone through the following questions on Stack Exchange and other few questions too: Why is managing CG (centre of gravity) important? How are the limits of the center of gravity chart ...
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### What is the effect of moving the centre of gravity ahead or behind the aerodynamic centre for HALE UAVs?

I have heard a lot about keeping the centre of gravity (CG) behind the aerodynamic centre (AC)will give better performance than keeping CG ahead of AC (for UAVs require high performance). However, I ...
391 views

### What aircraft design elements contribute the most to sustained flight?

If I wanted to design an aircraft for autonomous operation and maximum endurance, what design philosophies provide the greatest benefit? I'm imagining a powered glider. Does not have to be highly ...
289 views

### Are the implications of weight and balance for rotary wing aircraft similar to fixed wing aircraft?

Original discussion here. How does weight and balance for rotary wing aircraft work? Is lateral CG more or less of an issue, or is it comparable to fore/aft CG since the lifting surface is rotating ...