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Post by beeker46 on Jun 13, 2020 13:01:27 GMT -5
At what point, degree-wise, are winds no longer considered 'headwinds'? 10 degrees off the nose, 15 degrees, 20? 25? Is there a particular moment when wind direction is no longer considered as a headwind, and non-headwind power settings can be utilized? Or is it more about ground speed point to be reached, instead of actual headwinds?
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Post by Tom/CalClassic on Jun 13, 2020 13:38:28 GMT -5
Headwinds are always headwinds, no matter how small. You still have to take them into account. That said, it will vary when you need to take action - and that can't always be reduced to a simple rule. That depends on your flight planning.
If I'm flying a plane with Notepad gauges and you plan a flight using it, it should warn you about headwinds. Here is what the Notepad readme says about that:
"In the absence of these warnings all cruise is conducted in Economical cruise power to conserve fuel and engine wear, save for the L-1649A which uses normal cruise power unless flying a near max range sortie. Your scripted response to these three warnings (Significant Headwinds, Severe Headwinds, Significant Tailwinds) is described in Part 2 of the Propliner Tutorial. Briefly you should increase by one cruise power setting for a Significant Headwind, by two cruise power settings (if available) for a Severe Headwind, and decrease by one cruise power setting for a Significant Tailwind. You will usually also need to change altitude as explained in the Propliner Tutorial."
If you are not flying using the Notepad gauges, then the ground speed can indeed be used as a guide. Assuming you planned your fuel using the Fuel Planner gauge (or used the same planning logic) it gives you a 15% fuel reserve for headwinds. If the headwind component is much less than 15% of your planned true airspeed, then you may not need to increase your power setting and should still arrive with proper fuel reserves. If it even comes close to 15% though, you probably should.
BTW, The Fuel Planner logic is to add 15% route fuel for headwinds, 45 min at econ power for holding, and 45 min at econ power for diversion. If you are flying to an isolated location (like an island, for example) the diversion reserve may need to be increased. Similarly, if your destination airport is reporting bad weather, the holding reserve may need increasing.
Hope this helps,
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Post by beeker46 on Jun 13, 2020 17:35:51 GMT -5
Ahh, it is determined by ground speed, I understand. Since I fly aircraft that do not have the Fuel Planner gauge, as well as aircraft that does, I will go by groundspeed. Makes sense, and now that I understand that, I can incorporate it. Many thanks, Tom.
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