# What is the drag (or $C_D$ vs $C_L$) of the Airbus A320 in cruise flight?

Is there any website or data-sheet that I can find drag of airplane for cruise conditions. $$C_D$$ vs $$C_L$$ graph is also acceptable.

To be more specific I am searching drag values of A320 in cruise flight.

• In unaccelerated, straight and level flight, total drag is equal to total thrust. Perhaps you may find the data on the total thrust provided by the engines of the A320 under cruise conditions. That would answer your question. Commented Oct 14, 2018 at 15:20
• Thank you for your answer, I cannot find a website that provide information about cruise thrust Commented Oct 16, 2018 at 17:37
• Try to find the best L/D for the A320. Probably, that's also the L/D at cruise flight. From the weight of the A320 and the L/D, you can easily compute the total drag of that airplane... Commented Oct 16, 2018 at 18:00
• At level flight, constant speed, the total drag is not equal to total thrust , since total thrust is weight related. So certainly not in « accelerated » flight Commented May 28, 2019 at 16:33

## 1 Answer

I need to make a few assumptions to close the gaps in the data you provide.

1. The aircraft flies close to its optimum L/D - which is 18 for the A320-200 in cruise. So the $$c_D$$/$$c_L$$ is 0.055556.
2. The aircraft is close to its maximum take-off mass, minus fuel for climb. Let's pick 76 tons.

Now the drag force is 1/18 of the weight force. Weight is mass times gravitational acceleration: 745,300 N. So drag would be 41,406 N at this point.

At the end of the trip the aircraft has burnt through 15 tons of fuel; now the drag is a mere 34,300 N. Note also that it now is flying quite a bit higher than initially in the flight, so both friction and induced drag have become smaller.