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 Ballast:: running against a wind &making the field
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22 Posts

Posted - 12/10/2012 :  4:54:03 PM  Show Profile
Just looked up some info and found to my suprise a here-to-for unknown fact (to me) even thou I have been flying full scale and models for the last 30 years. Here's the question as posed in AOPA Pilot last month.
A plane has a published glide ratio of 10:1 (10,000 feet horizontal for avery 1,000 feet elevation.) at 75 knots. Of course at zero wind conditions.
If the same plane looses 10% weight and glides at the same speed will the plane's glide ratio
A increase
B decrease
C stay the same
D cannot be determined

Now I know some of you are are a lot better at this than me but the correct answer is B. One must slow down the plane to keep the glide ratio the same.
The obvious reason I'm interested in this is that I landed in the trees at two of the 5 contests I attended this year with a 54.5oz Supra. So for the last 30 years, I had figured lighter is always better. No ballast ever!! Well maybe in my Paragon in 1985. The Supra's a great contest ship and with a good launch in no wind or lift conditions you can almost always make at least 8 minutes, but add the wind and now it requires skill to make the task.
So if you slow the plane down in a 15kt headwind you will never make it back to the field. It will just hover at best L/D over the trees till it gently alights in a branch. Which is why I spent the better part of 2 contests looking for a lost plane.
I keep asking myself, How can you be in this hobby for 30 years and still be so stupid?
I asked for ballast in my stocking this Christmas.



477 Posts

Posted - 12/10/2012 :  5:17:27 PM  Show Profile
You live and you learn. That is half the fun. ;)

Best regards,
Ed Anderson
Long Island Silent Flyers
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