To take a slightly different tack...

If you look at a lot of beginning racers, their speeds tend to hover in the low 40mph range for typical "good" East Coast days (5,000 feet with 4kts and Cu) while the fast guys in the same class are doing 60-65.

So, if you're a beginner, your best bet is to look at any XC flying you've been doing and figure out how fast you've typically been able to go on similar days. Divide the task distance by that speed and that's about what it will take you to finish. Work backwards from that assuming you want to be back on the ground by 5 pm to figure out when you need to start. If it's a time-limited task (say a 3.5 hour area task), then multiply that speed by the time to get a rough idea how far you will have to fly.

P3


On Monday, December 2, 2013 1:15:26 PM UTC-5, Tom Kelley #711 wrote:
On Monday, December 2, 2013 8:44:00 AM UTC-7, wrote:

Hi



In is book S. Kawa write that in AST you have to determine the "task required speed". He do not explain how or what this mean. I know the speed after the flight.



Explanation please



Thank you



This may help you compute the task speed for the day. As a simply example, lets say that we will have clouds and the bases will be 5,000 agl. Take 60% of that and your achieved climb should be around 3.0 kts. Now, some software used on PDA's, allows you to enter in this MC of 3.0. Now this should show you the speed and time around the called task whcih you had already entered into the PDA. Using this, you can get an idea of the best time to start. Considering your experience, you might either want to start earlier or later if YOU feel how you think the day is going. Watch the morning temp rise is important, as it gives an idea if the day will be warmer/cooler than forecast. For every degree warmer, it will roughly raise the cloud base 400 ft. As the could base rises, the lift factor should also rise. Of course things like streeting and boomers will affect this, but its a place to start.. Some planning is better than nothing.



Some will use a factor of 60-70 percent, or their own brew.



If your PDA can't supply this information, is why you should understand the polar of your glider. As using the achieved climb rate with your polar will result in giving you your cross country speed for this day. To find out how to do this, please read the ANDY DAVIS article found on this link. Also, you will find other outstanding articles to read.



http://www.dragonnorth.com/djpresentations/index.html



Its best to remember to start and complete the task. Keeping notes at the end of your day is also a good habit to develop. Some notes may include spending a few minutes looking at you IGC file. As it shows you where you found the best climbs at or other areas. Marking these spots on a paper map and after a few days of soaring, will start showing a trend as to areas you might not want to go! Keeping notes of how the weather turned out verses how it was forecast can be of paramount importance.



This is just a start for you. Reading those articles will bring new information, NOT all, as you will add some over the years.



Best Regards, #711.