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### AuthorTopic: Ann Birney-Ride into History Tour  (Read 912 times)

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##### Ann Birney-Ride into History Tour
« on: January 27, 2019, 10:36:48 PM »

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#### Martin X. Moleski, SJ

• Posts: 2949
##### Re: Ann Birney-Ride into History Tour
« Reply #1 on: January 28, 2019, 02:00:11 AM »

At one time she was asked the question of navigation and being off course and she said that the pilots had a way of literally throwing their navigation off to keep on track with head winds. True or False.

There is a grain of truth in there somewhere.

But it is not "throwing their navigation off" nor is it a matter of "keeping track with head winds."

Cars, as a general rule, are not blown off course by cross-winds.  The friction between the tires and the road means that, as a general rule under normal conditions, the car goes where you point it.

An airplane lacks that helpful contact with the ground.  Only if the wind is coming directly from the heading you want to fly to reach your destination can you use your compass to steer you to your destination.  If the cross wind is directly perpendicular to your intended path, it will cause you to move with it in that direction even though you are keeping the nose of the airplane in line with a different compass heading.

NASA article on "Cross Winds."

In order to make your ground track align with your path to your destination, you must now point the nose of the aircraft into the wind just the right amount to offset the force of the wind that is carrying you off-course.

If you don't know the exact velocity and angle of the cross-winds, you have to guess the right amount of compensation to dial in between a line drawn on the map from where you are to where to want to be and the actual line being drawn across the ground by the combination of your own airspeed and orientation with the angle and strength of the cross winds.

Fred could only give Amelia new vectors to fly when he could establish their position with some degree of certainty, which would help him to measure the force of the crosswinds they had encountered during the time since their last fix.  There was also a drop tube and a drift sight built into the Electra so that the navigator in the rear could drop flares (?) on the ocean and estimate drift.  See the "Luke Field Inventory," which shows that AE had "Aluminum Direction Bombs" on board when she attempted to take off from Hawaii--"containers of aluminum powder to be dropped onto the surface of the water as a target for a drift meter so that a navigator can judge wind direction and speed."

That these containers were meant to burn is my own conjecture or unclear memory.  I can't find a simple description of them on Google at the moment.  In daylight, I think the navigator could look at wave patterns with the drift sight without having to drop any markers.
LTM,

Marty
TIGHAR #2359A

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