Radius of turn
Thread Starter
Joined: Apr 2002
Posts: 37
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From: LJCE
Radius of turn
Hay!
I need some help. My instructor gave me a task, to find out, from where the rule of thumb equation for radius of standard turn ( r(nm)= TAS(kt)/200) is derived from. The more precise equation is: r(NM)= TAS(kt)/189,4, for rate R=3°/s turn.
I know that full equation for radius of turn in NM is:
r= TAS(kt)/ rate of turn(1,2,3,)x60x3,14(pi)
thanks for answer!
I need some help. My instructor gave me a task, to find out, from where the rule of thumb equation for radius of standard turn ( r(nm)= TAS(kt)/200) is derived from. The more precise equation is: r(NM)= TAS(kt)/189,4, for rate R=3°/s turn.
I know that full equation for radius of turn in NM is:
r= TAS(kt)/ rate of turn(1,2,3,)x60x3,14(pi)
thanks for answer!
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Posts: n/a
Just had a chat with some little schoolboys.....Their answer was:
180 Kts means 180 NM per hour....
divided by 60 minutes gives 3 NM / min
multiplied by 2 min (as in "standard turn") gives 6 NM which is the complete circle.
This divided by 3.1415 gives 1.9099 NM as the diameter
This divided by 2 gives 0.9549 as the radius....
The rule of thumb divides 180 by 200 which equals 0.9......
Now...where was the problem???
180 Kts means 180 NM per hour....
divided by 60 minutes gives 3 NM / min
multiplied by 2 min (as in "standard turn") gives 6 NM which is the complete circle.
This divided by 3.1415 gives 1.9099 NM as the diameter
This divided by 2 gives 0.9549 as the radius....
The rule of thumb divides 180 by 200 which equals 0.9......
Now...where was the problem???
Joined: Aug 2002
Posts: 56
Likes: 0
From: Australia
Geometry.
Circumference (c) = 2 x pi x radius (r)
or r = c / 2 pi
Rate 1 turn = 2 minutes
@ 100Kt, 2 minutes = (100 x 2 / 60) nm = c (approximately)
so r = (100 x 2 / 60) / 2 x 3.1428
on your calculator = 0.5303 or approximately 0.5
So at 100kts r = 0.5nm or 0.5% IAS
For mental arithmetic purposes assume TAS = IAS and use the formulae radius of turn at rate one = 1/2 % IAS
Circumference (c) = 2 x pi x radius (r)
or r = c / 2 pi
Rate 1 turn = 2 minutes
@ 100Kt, 2 minutes = (100 x 2 / 60) nm = c (approximately)
so r = (100 x 2 / 60) / 2 x 3.1428
on your calculator = 0.5303 or approximately 0.5
So at 100kts r = 0.5nm or 0.5% IAS
For mental arithmetic purposes assume TAS = IAS and use the formulae radius of turn at rate one = 1/2 % IAS
