Thursday, 18 August 2011

drift without triangles

click image for clear view

A friend sent me an Excel spreadsheet devised by Joan Walsh at Saxon Microlights and it is absolutely brilliant (I can't find a way to attach the spreadsheet for download from the blog, sorry). If I had an i-phone I would want this as an app.

It works out your drift and ground speed based on the angle of head or tailwind, your indicated airspeed and track required. Also it works out your flying time and your fuel usage .....all in seconds as one calculation.

On advice from a friend I used the spreadsheet to generate figures for a chart I can carry in my bar-mitt pocket, so that it is always visible. Then if I mark the wind on my chart I should be able to work out my compensation for drift without drawing triangles or even getting out my Flylight calculator. But it will take practice working out the wind relative to the aeroplane.

I have worked out my data based on a 60mph/ 52 Kt indicated airspeed. Other data can be interpolated, of course, but in a weightshift it is rarely that precise an art anyway. In effect I have worked out my triangles in advance for every eventuality.

I love it!

Many thanks to my modest friend and to Joan Walsh.

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