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#1
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As many may know, we set records here in Iowa yesterday, hitting 73 degrees
in Iowa City. It felt great! The winds in the afternoon started to kick up pretty good, as a cold front approached from the northwest. On our way back from brunch in Lone Rock, WI (where we ran into this group's own Jim Burns, figuratively speaking. We actually passed on the taxiway...) the wind was humming along at about 40 knots, right on the nose. It was smooth at 6500 feet, though, so Mary and the kids were content to nap all the way home. Iowa City AWOS was reporting 20 gusts to 26, but right down Rwy 25. As I entered the pattern, however, it became very apparent that the winds at pattern altitude were markedly different from the reported surface winds, with a very strong southerly component that was pushing me in too close on downwind. As I turned from base to final, the unexpectedly strong wind had me bent out of shape pretty good, but I managed to wrestle the runway back into alignment without entering the coffin-corner of cross controlling. Nevertheless, I was amazed to find that it was taking full left aileron and right rudder to keep the runway in the windshield. This wind was clearly NOT down the runway. Asking Mary to get AWOS for me, the mechanical man was still reporting winds at 240 -- perfect for Rwy 25. As I cursed the stupid AWOS equipment -- which was clearly malfunctioning (or so I thought) -- I told the kids to hang on for a wild ride. They weren't disappointed. On short final, it felt as if someone had kicked up on the left wing from below with all their might, and we banked hard (toward our hotel!) away from the runway. We were low, and slow, and things didn't look good, but just as quickly as you can say it, I was able to right us, and the wind was suddenly and instantly right down the runway. Surprisingly, despite the wild approach, I continued my unexplained streak of perfect landings, causing nary a squeak. Only difference was, this time I was slightly out of breath, and I had a death-grip on the yoke... ;-) Talk about wind shear. There was a nearly 90 degree difference in the wind direction at MAYBE 500 feet (or less) off the ground. And both wind "streams" were whistling right along, too. Now today it's 35 degrees, and dropping like a stone -- with winds of well over 30 knots. Gotta love the Midwest in late winter! -- Jay Honeck Iowa City, IA Pathfinder N56993 www.AlexisParkInn.com "Your Aviation Destination" |
#2
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The front must have been approaching Iowa and northern IL faster than it was
here in Wisconsin. We stopped at Adams 63C on the way home for 32 gallons of cheap $2.32 100 LL. On the way from LNR to 63C we did a "speed run" just to check the Aztec's performance. Using the KLN 94, it calculated the winds at 3500 ft to be from 200 at 14, surface winds were 240 at 6. 26" and 2400 RPMs gave us a TAS of 200mph, just shy of the always optimistic book figure of 205mph. The rest of the afternoon at STE winds were 240 at 6. Lots of planes out in the nice weather, even a Luscumbe practicing crosswind landings. Later in the evening it must have picked up, because a friend of mine reported flying north from Prairie Du Chien in his C170 with a 150kt ground speed. Now it's 34011G22 and temps dropped from 53 yesterday to 27 now and still falling. Rain, sleet, and snow all mixed. Spring in Wisconsin is spelled SwPiRnItNeGr, because every other day is one or the other. I was happy to see Jay and Mary taxi up in the Pathfinder and almost wished we would have had the "slower" waitress so we could have met before we cranked up the Aztec. The combination of Mary's voice on the radio, two kids in the back seat, Jay with his camera, and that great looking paint job left little doubt as to who it could be! Jim |
#3
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The combination of [...] and that great looking paint job
left little doubt as to who it could be! He painted his =airplane= purple?? Jose -- Math is a game. The object of the game is to figure out the rules. for Email, make the obvious change in the address. |
#4
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![]() "Jay Honeck" wrote in message news:OUZWd.42901$r55.23167@attbi_s52... As many may know, we set records here in Iowa yesterday, hitting 73 degrees in Iowa City. It felt great! The winds in the afternoon started to kick up pretty good, as a cold front approached from the northwest. On our way back from brunch in Lone Rock, WI (where we ran into this group's own Jim Burns, figuratively speaking. We actually passed on the taxiway...) the wind was humming along at about 40 knots, right on the nose. It was smooth at 6500 feet, though, so Mary and the kids were content to nap all the way home. Iowa City AWOS was reporting 20 gusts to 26, but right down Rwy 25. As I entered the pattern, however, it became very apparent that the winds at pattern altitude were markedly different from the reported surface winds, with a very strong southerly component that was pushing me in too close on downwind. As I turned from base to final, the unexpectedly strong wind had me bent out of shape pretty good, but I managed to wrestle the runway back into alignment without entering the coffin-corner of cross controlling. Nevertheless, I was amazed to find that it was taking full left aileron and right rudder to keep the runway in the windshield. This wind was clearly NOT down the runway. Asking Mary to get AWOS for me, the mechanical man was still reporting winds at 240 -- perfect for Rwy 25. As I cursed the stupid AWOS equipment -- which was clearly malfunctioning (or so I thought) -- I told the kids to hang on for a wild ride. They weren't disappointed. On short final, it felt as if someone had kicked up on the left wing from below with all their might, and we banked hard (toward our hotel!) away from the runway. We were low, and slow, and things didn't look good, but just as quickly as you can say it, I was able to right us, and the wind was suddenly and instantly right down the runway. Surprisingly, despite the wild approach, I continued my unexplained streak of perfect landings, causing nary a squeak. Only difference was, this time I was slightly out of breath, and I had a death-grip on the yoke... ;-) Talk about wind shear. There was a nearly 90 degree difference in the wind direction at MAYBE 500 feet (or less) off the ground. And both wind "streams" were whistling right along, too. Now today it's 35 degrees, and dropping like a stone -- with winds of well over 30 knots. Gotta love the Midwest in late winter! -- Jay Honeck Iowa City, IA Pathfinder N56993 www.AlexisParkInn.com "Your Aviation Destination" In NV, I remember flying along in smooth air with 130kts of wind at 19,000' and hearing the AWOS saying "wind calm". You knew you were probably in for a beating somewhere during the descent. The area had frequent inversions at night and the wind would go from high speed to dead calm in a few hundred vertical feet. I also experienced (over UT) winds from the east at 120kts at FL290 and from the west at 25kts at FL250. I reported this and it wasn't long before all the eastbound airliners were down at FL250. I wouldn't have thought it possible before seeing it for myself. I always thought that winds just filled low pressure areas from high pressure areas but apparently, it is more complicated. Mike MU-2 |
#5
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it was a weird day (and night).
I was flying on the UW MedFlight Augusta 109 late Saturday night, early Sunday am this weekend and on a flight to Mauston, and then later to Viroqua, we were showing only 95-100 knots heading to the NW from Madison. On the way back, with a patient on board, we were doing about 205 knots! Which was a blessing with a sick patient on board, keeps the time to a minimum. The shear factor wasn't as big of a deal overnight, which is also a blessing because the approach to the UW helipad is like flying into a canyon. And now we have a crane on top of the hospital to worry about... Ryan Wubben Madison, WI |
#6
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Jay Honeck wrote:
[cut] As I turned from base to final, the unexpectedly strong wind had me bent out of shape pretty good, but I managed to wrestle the runway back into alignment without entering the coffin-corner of cross controlling. [cut] What is a coffin-corner and how does one get into it in the pattern? |
#7
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Milen Lazarov wrote:
Jay Honeck wrote: As I turned from base to final, the unexpectedly strong wind had me bent out of shape pretty good, but I managed to wrestle the runway back into alignment without entering the coffin-corner of cross controlling. What is a coffin-corner and how does one get into it in the pattern? Jay frivolously used that well defined term completely wrong, presumably just because it sounds good. (A tactic which some journalists use, too, especially when they write about aviation...) You never get into the coffin corner at pattern altitude. The stall speed is constant with indicated airspeed, while Vne is constant with true airspeed (acually, it decreases somewhat at high altitudes). So there is a point, at very high altitudes, where Vs meets Vne. This point is called the coffin corner, because you can't escape from it (except by descending): You can't slow down (stall) nor accelerate (Vne). Stefan |
#8
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I'll agree with Stefan that this term gets mixed usage. What Stefan refers
to is mainly a consideration for high altitude aircraft. The U2 is the plane that instantly comes to mind. Think about pulling back, stall... Think about pushing forward Vne.... not much room in between. What I refered to in my response, I generally refer to as the Deadman's Corner, it instills the seriousness of proper airspeed control, coordination, and patience when teaching primary students proper landing patterns. Jim |
#9
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![]() "Stefan" wrote in message ... Milen Lazarov wrote: Jay Honeck wrote: As I turned from base to final, the unexpectedly strong wind had me bent out of shape pretty good, but I managed to wrestle the runway back into alignment without entering the coffin-corner of cross controlling. What is a coffin-corner and how does one get into it in the pattern? Jay frivolously used that well defined term completely wrong, presumably just because it sounds good. (A tactic which some journalists use, too, especially when they write about aviation...) You never get into the coffin corner at pattern altitude. The stall speed is constant with indicated airspeed, while Vne is constant with true airspeed (acually, it decreases somewhat at high altitudes). So there is a point, at very high altitudes, where Vs meets Vne. This point is called the coffin corner, because you can't escape from it (except by descending): You can't slow down (stall) nor accelerate (Vne). Stefan I always thought that the "coffin corner" was where stall speed met the Mach limit. I didn't think that it even applied to non-jet aircraft. Mike MU-2 |
#10
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![]() "Mike Rapoport" wrote I always thought that the "coffin corner" was where stall speed met the Mach limit. I didn't think that it even applied to non-jet aircraft. Mike No, I think the post above yours got it pretty much right..Vne is significant, in that it demonstrates itself by nasty things like flutter, or control reversal. Pull back on the stick to maneuver, or slow down, and stall, or at least buffet like hell. It is true, however, that it is pretty tough for a non jet aircraft to get to the coffin corner. The Exxon tiger (can't think of the guy's name) that has been trying to get the piston altitude record, has said that he is really close to getting into coffin corner. -- Jim in NC |
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