Trijetsonly From Germany, joined Jul 2009, 197 posts, RR: 0 Posted (8 months 2 weeks 5 days 23 hours ago) and read 2611 times:
after flying now between a local city pair with ~350km distance inbetween for several years, I made following consideration:
Assuming that you have two airports with the similar runway direction and the direction from one airport to the other is similar to their runway direction:
Until which wind speed and distance between the airports, the flight is more economic with headwind because you don't have to circle or fly traffic patterns on departure and arrival? (no holdings in this case)
So the point is, that the total flying distance is longer with tailwind, because takeoff and landing are in the wrong direction with headwind. How strong has the wind to be, to compensate the total distance flown.... OR how long has the direct distance to be that even a slight tailwind compensates the additional circling/pattern distance?
So I guess one can draw a graph with head-/tailwind speed on one axis and the distance between those two airports on the other axis.
As a result we get a line which shows the breakeven-point.
oly720man From United Kingdom, joined May 2004, 6684 posts, RR: 11
Reply 1, posted (8 months 2 weeks 5 days 17 hours ago) and read 2461 times:
There are far too many variables to make a meaningful determination and the likelihood is that any optimum condition will occur so rarely it will be little more than an academic exercise.
The flying distance isn't the issue it's the flying time, fuel's measured in volume per hour. You can fly a longer distance but with a suitable headwind/tailwind a higher ground speed will mean you're not in the air as long as on another day with less wind.
Though having said that there can be ATC procedures in place to improve flight performance by optimising routes and approaches to airports.
atct From United States of America, joined Mar 2001, 2265 posts, RR: 38
Reply 5, posted (8 months 2 weeks 4 days 9 hours ago) and read 1986 times:
All depends on the type of aircraft, runway available . weather, etc.
Taking the KingAir into a 12,000ft dry runway, I'd take a 20kt tailwind component on takeoff or landing to save 5 minutes. When we went into 3000ft runways, always take the headwind and a nice long stable approach. Flying my J3, anything more than 5kts on the tail and I was chirping for into the wind operations. I've landed with a 15kt tailwind in the J3 and its not fun. Many many variables.
"The way to get started is to quit talking and begin doing." - Walt Disney
skyhawkmatthew From Australia, joined Oct 2005, 147 posts, RR: 0
Reply 6, posted (8 months 2 weeks 3 days 2 hours ago) and read 1760 times:
Over a 350 km stage length...
Let's assume the time taken to fly a circuit instead of a straight in approach adds 3 minutes to the flight time (ignoring changes in taxi time).
If the sector usually takes 40 minutes to the commencement of the approach, that's an average speed of 284 knots. Taking 43 minutes instead, and making a straight-in approach, such that the overall time spent is the same, requires an average speed of only 264 knots, that is, anything less than a 20 knot average headwind means the straight in approach will save time.
Of course, wind speeds vary dramatically with altitude, so this is a very vague generalisation!