Louie Posted December 12, 2014 Share Posted December 12, 2014 At the risk of opening both ends of the can... i think he's right, it is important to understand so i am hoping I didn't misunderstand (or lead anyone else to) when i posted my thread. So in my mind... my understanding is this - If i am at 65 kts on short final with a crosswind, and it then becomes a tailwind (let's say 10 kts), my ground speed would indeed increase, which would lead me to perceive that I am going faster than i am, but would it not be true that my actual airspeed (ie air flowing over the wings) in fact be 10 kts lower? Yep can of worms open and no airspeed does not change. Really important for all to understand but I will leave that to perhaps Motz to comment. Maybe new thread. Link to comment Share on other sites More sharing options...
motzartmerv Posted December 12, 2014 Share Posted December 12, 2014 Ok ok..We have to contain the example to one context. ayavner, your description WOULD see a change in IAS, because your talking about a sudden "Wind" change. As apposed to a constant wind and the aeroplane "turning" . They are very different scenarios. Sudden changes in wind strength OR direction is known as wind shear. It WILL change your IAS, sometimes very rapidly. Heading changes in a constant wind should NOT cause a change in IAS, but will cause a groundspeed change. There is a little "in between' science that some will argue, but Generally, the above statements are true. Ive got worms on my chin now!!!!! Link to comment Share on other sites More sharing options...
facthunter Posted December 12, 2014 Share Posted December 12, 2014 IF you in an moving airmass , you can go around and around and your airspeed will not vary but your groundspeed will. If you climb or descend into a windshear situation your airspeed WILL change at the boundary. You can also get a wind direction change at a constant height, the most dangerous being a downburst situation near storm activity. Nev 1 3 Link to comment Share on other sites More sharing options...
ayavner Posted December 12, 2014 Share Posted December 12, 2014 haha OK well that was my context, and hopefully in that light some of the worms can go back into the can. i was not looking at the IAS at the time, but surmise that is what happened as the sock was back and forth all day (literally in the blink of an eye a couple times as I sat there afterwards with my coffee, reflecting). Louie you're right though, and ASI shouldn't change just with the normal changes of wind direction experienced on a cross country flight for example. Link to comment Share on other sites More sharing options...
ayavner Posted December 12, 2014 Share Posted December 12, 2014 IF you in an moving airmass , you can go around and around and your airspeed will not vary but your groundspeed will. If you climb or descend into a windshear situation your airspeed WILL change at the boundary. You can also get a wind direction change at a constant height, the most dangerous being a downburst situation near storm activity. Nev Right and this is what I was talking about in my example. I probably should have used the word windshear, but my brain had faded. Link to comment Share on other sites More sharing options...
facthunter Posted December 12, 2014 Share Posted December 12, 2014 The airspeed will certainly vary if you get in severe turbulence where the wind is tumbling or rotating and you will get varying up and down currents as well as horizontal variations. I had a bad one where the airspeed went from about 50 to 140 knots fluctuating, without attitude change. You are going from stall almost to way over VNE and there is not a lot you can do about it except avoid abrupt control inputs. Nev Link to comment Share on other sites More sharing options...
motzartmerv Posted December 12, 2014 Share Posted December 12, 2014 Only prang Ive had was due to windshear. The little guzzelle went from a healthy 65 kts, to being a pole top ornament in the blink of an eye. 1 Link to comment Share on other sites More sharing options...
facthunter Posted December 12, 2014 Share Posted December 12, 2014 It can happen to any of us. I like to have some power on in those circumstances and be ready to give it the lot if it starts to fall out of the sky. but luck has a big part in it. Nev Link to comment Share on other sites More sharing options...
motzartmerv Posted December 12, 2014 Share Posted December 12, 2014 The winds on the day were nothing too serious, about 15kts, gusting to about 20-25. The issue was mechanical turbulence off a hangar right next to the runway, which caused (what I believe) to like a horizontal rotor, which pushed us from behind, rapidly, and took the IAS down to nothing. She fell from windsock height like an express elevator. Full power was in when we impacted. I wasnt on the controls, it was during a BFR. But, it would have happened anyway, even if I was. 1 Link to comment Share on other sites More sharing options...
ayavner Posted December 15, 2014 Share Posted December 15, 2014 Ouch, did your back hurt after that? I always find a day or 2 after a firm landing that my back is a little sore, possibly from tensing up. Link to comment Share on other sites More sharing options...
motzartmerv Posted December 15, 2014 Share Posted December 15, 2014 Yea, it hurt. Link to comment Share on other sites More sharing options...
cooperplace Posted December 15, 2014 Share Posted December 15, 2014 When you think you have it skun, you are ready to be a menace to yourself and anyone around you. You have also stopped learning, which I have always said not to do.Not a bad idea after a flight to review the way you conducted it VERY HONESTLY. That way you will improve, not deteriorate.. Nev agree 100% re v honestly do a flight review. Whenever I do a silly thing, or a forgetting of the basics, the best way I learn from it is to do the honest flight review. Definitely the best policy. Link to comment Share on other sites More sharing options...
Ultralights Posted December 15, 2014 Share Posted December 15, 2014 there is a reason the ASI can jump around in turbulence... Link to comment Share on other sites More sharing options...
facthunter Posted December 15, 2014 Share Posted December 15, 2014 You have my attention..... Nev Link to comment Share on other sites More sharing options...
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