SlimHeader

facebook_page_plugin
×
Q and A video streaming session (31 Mar 2020)

Would you like a live-streamed Q and A session?

It can be hard to learn in isolation. We don’t know when the classroom can return, but could help bring the classroom to you.

Would you find its valuable to participate in a live-streamed Q and A session?
You can submit questions prior to the event, as well as submit them during live chat.

Would you sign up for this?
We would love to hear your feedback.

Email the office to register your interest and what subject you would like covered. This email address is being protected from spambots. You need JavaScript enabled to view it.

Cheers
Stuart

× Welcome to the CPL Aerodynamics question and answer forum. Please feel free to post your questions but more importantly also suggest answers for your forum colleagues. Bob himself or one of the other tutors will get to your question as soon as we can.

Exercise A1 question 3

  • Posts: 92
  • Thank you received: 0

jukzizy created the topic: Exercise A1 question 3

For an aircraft in level flight to cover the greatest possible time per litre of fuel consumed, it must be flown at a speed which requires
A) The least amount of drag
B) The smallest angle of attack
C) The least amount of power
D) The best lift/drag ratio

The answer in the book is "A"

Just want to know if anyone can explain to me why the answer cannot be D) The lowest possible fuel flow.
#1

Please Log in or Create an account to join the conversation.

  • Posts: 412
  • Thank you received: 60

Stuart Tait replied the topic: Exercise A1 question 3

At the lowest possible fuel flow the power levels would very low as such your airspeed would be low, so induced drag would become a factor as you would need a larger angle of attack, so you would travel less distance per litre of fuel burnt. (ie: maximum endurance)
#2

Please Log in or Create an account to join the conversation.

  • Posts: 92
  • Thank you received: 0

jukzizy replied the topic: Exercise A1 question 3

thank you sir
#3

Please Log in or Create an account to join the conversation.

  • Posts: 111
  • Thank you received: 16

Carello replied the topic: Exercise A1 question 3

The question asks for a speed to "cover the greatest possible time per liter of fuel consumed". In other words, the question is asking for the best endurance speed. It is a time question.

For any aircraft, best endurance occurs when the fuel flow is at a minimum for level flight. For a piston engine aircraft this will occur when the power required for level flight is at a minimum. You may recall that FF is proportional to power in a piston engine aircraft - the lower the power setting, the lower the fuel flow, the greater the endurance.

With the above in mind, the correct answer is "C" not "B"
#4

Please Log in or Create an account to join the conversation.

  • Posts: 92
  • Thank you received: 0

jukzizy replied the topic: Exercise A1 question 3

Thanks alot sir
#5

Please Log in or Create an account to join the conversation.

  • Posts: 18
  • Thank you received: 1

baddles replied the topic: Exercise A1 question 3

In the current version of the CADA book, this is Question 4, with correct answer (c).
#6

Please Log in or Create an account to join the conversation.

Time to create page: 0.221 seconds