Contents

- 1 What is CL and CD?
- 2 What is a good lift to drag ratio?
- 3 Why should you fly at maximum LD ratio?
- 4 What are 3 things needed for flight?
- 5 How do you read a CD or CL chart?
- 6 How do you calculate CD and CL?
- 7 What is drag curve?
- 8 What is minimum drag speed?
- 9 Does drag affect lift?
- 10 What is maximum L D ratio?
- 11 How is glide ratio calculated?
- 12 How do you reduce drag?
- 13 Can I bring perfume on a plane?
- 14 What can I not bring on an airplane?
- 15 Can I bring snacks on a plane?

## What is CL and CD?

The lift/drag ratio is used to express the relation between lift and drag and is determined by dividing the lift coefficient by the drag coefficient, CL / CD. A ratio of L/D indicates airfoil efficiency. The maximum lift/drag ratio occurs at one specific CL (Lift Coefficient) and AOA (Angle of Attack (AOA)).

## What is a good lift to drag ratio?

This is especially of interest in the design and operation of high performance sailplanes, which can have glide ratios almost 60 to 1 (60 units of distance forward for each unit of descent) in the best cases, but with 30:1 being considered good performance for general recreational use.

## Why should you fly at maximum LD ratio?

As discussed on the maximum flight time page, low fuel usage allows an aircraft to stay aloft for a long time, and that means the aircraft can fly long range missions. So an aircraft with a high L / D ratio can carry a large payload, for a long time, over a long distance.

## What are 3 things needed for flight?

The four forces are lift, thrust, drag, and weight. As a Frisbee flies through the air, lift holds it up.

## How do you read a CD or CL chart?

To find the best glide ratio, you have to draw a line from the origin ( Cl =0/ Cd =0) tangentially to the curve. Read the values of Cl and Cd at the point where the line touches the curve and calculate Cl / Cd, the glide ratio. The “lift polar” shows the lift coefficient Cl, plotted versus the angle of attack alfa.

## How do you calculate CD and CL?

This creates a swirling flow which changes the effective angle of attack along the wing and “induces” a drag on the wing. The induced drag coefficient Cdi is equal to the square of the lift coefficient Cl divided by the quantity: pi (3.14159) times the aspect ratio AR times an efficiency factor e.

## What is drag curve?

The power required curve represents the amount of power needed to overcome drag in order to maintain a steady speed in level flight. The propellers used on most reciprocating engines achieve peak propeller efficiencies in the range of 80 to 88 percent.

## What is minimum drag speed?

So the minimum power required (maximum endurance) occurs when is a maximum. Thus the minimum power (maximum endurance) condition occurs at a speed which is 3^{–}^{1}^{/}^{4} = 76% of the minimum drag (maximum range) condition. The corresponding lift-to- drag ratio is 86.6% of the maximum lift-to- drag ratio.

## Does drag affect lift?

Drag acts in a direction that is opposite to the motion of the aircraft. Lift acts perpendicular to the motion.

## What is maximum L D ratio?

If the airplane is operated in steady flight at ( L / D ) _{MAX}, the total drag is a a minimum. Any angle of attack lower or higher than ( L / D ) _{MAX} reduces the lift-drag ratio and consequently increases the total drag for a given airplane lift. Many important items of airplane performance are obtained in flight at ( L / D ) _{MAX}.

## How is glide ratio calculated?

Glide Ratio = Horizontal Distance divided by the Change in Altitude. Horizontal Distance = 50 feet Change in Altitude = 10 feet Dividing Distance (50) by Altitude (10) = 5 The Glide Ratio is 5 50/10 = 5/1 = 5 The glider flew forward 5 feet for every 1-foot drop in altitude.

## How do you reduce drag?

Frontal area Ways to reduce it include using the handlebar drops or aerobars. Getting down low into a crouched position with elbows in reduces drag because there is a more streamlined shape and there is less frontal area.

## Can I bring perfume on a plane?

In carry -on baggage, liquid perfume falls under the TSA’s 3-1-1 rule. The rule allows each passenger to pack liquids, gels and aerosols in containers of up to 3.4 ounces, with all containers fitting in a single 1-quart plastic bag. Bags get jostled during the screening process, especially checked bags.

## What can I not bring on an airplane?

Each country’s government has slightly different rules about what can and can’t be brought aboard a plane, but as a general rule you should never put any of the following in your carry -on: firearms, explosives, baseball bats or other sporting equipment that could be used as weapons, self-defense sprays (such as mace),

## Can I bring snacks on a plane?

Solid food items (not liquids or gels) can be transported in either your carry -on or checked baggage. TSA officers may instruct travelers to separate items from carry -on bags such as foods, powders, and any materials that can clutter bags and obstruct clear images on the X-ray machine.