Hi,
Q5) SEE Attached image
identical a/c in every respect except Gross weight to achieve maximum range in nil wind conditions
Answer is B - Heavier Aircraft Should Fly Faster than the light one .
This Makes sense as the Heavier Aircraft Requires More Lift to INC WEIGHT in Level Flight therefore this is achieved by what you choose to use and in this scenario you need to use a HIGHER IAS to achieve the extra lift required to Fly at the Best L/D AOA . understand you have also used more Power For Thrust to achieve the higher speed and which increases parasite Drag Not induced Drag, AND THIS IS WHAT WE NEED TO DO FOR RANGE TO FLY AT THE BEST L/D AOA NOT SPEED "IM ASSUMING".
THEN THIS QUESTION CONTRADICTING ANSWER ABOVE
Q7 ) Refers you to Total Drag Graph with Speed S being the Best L/D speed and question asks to use least amount of fuel in a given distance nil wind a/c must be flown at ..
answers:
A) At speed S for any weight (ANSWER IS A)
b) faster than speed S if weight increased
c) slower than speed s if weight increased
d) faster than speed s if weight is reduced
so the answer now being A above, contradicts answer to q 5 having to fly at a higher speed to achieve the L/D AOA at increased weight so my understanding and the confusion here is what question will BE asked about weight in relation to range,
SO WHEN WEIGHT IS INCREASED, FOR MAX RANGE.... IN NIL WIND
DO WE USE A HIGHER AOA AND USE THE Best L/D Speed OR....
USE AN INCREASED IAS AND THE BEST L/D AOA That we need To consider For Range ?
So it all comes down to what is the higher penalty with increased weight, the power thrust required for slight increase
in induced drag or parasite drag ?
am i on the right track or am i missing something ?
Thank You For your time