----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]----
Ed. Thank you for your nice advise. But the experienced wing lift was not due to a low tail. I had the rubber donuts replaced at my first annual and the tail is higher than I am (6.1) , no low tail here. I also have to mention that I solved a few landings before in strong X-winds with no such problem. I also had never a problem to get the Coupe run down straight the centerline. By reading through some other messages I found that if you don't crab the plane in the angle required for a centerline approach and hold the plane crabbed until it touches down, things get messed up. Like this Gentleman : "We had a ex Navy carrier pilot WWII have trouble landing a coupe crosswind. He held the crab coming in BUT straightened it up before touchdown." Hold it crabbed all the way until the wheels touch ground! In the moment he straightened the plane, the coupes direction of flight changed into somewhat off runway centerline. Picture it like this : Flying the Coupe down the extended runway line in a crab makes a nice straight lineup of the over 1000 pounds of mass a coupe represents. When hitting the ground lined up but crabbed , it does not matter much for the 1000 pounds of metal. That just wants to keep going the direction. The center of gravity of the plane is ahead of the mains. So, this centered gravity will pull your plane into the direction flown at touchdown and while doing so straighten out your Aircraft. In most cases this happens when the nose had not touched runway yet. Almost all Coupes I have seen are using the snubber cable, which holds the nose wheel way off the ground. If you fly the Coupe like intended, I guess one has to have a flexible grip on the controls when landing in a X-wind. However, pure physics allow the Coupe to run straight down the runway in a crosswind when flown down in a straight line. If you straighten out the Plane before touch down this line of mass - direction will be shifted by the same angle. Now it is off the runway and not anymore centerline. In this game it does not matter where the nose of the aircraft points to, but more which direction the 1000 pounds are pointing on touchdown. This explains the problems this Gentleman might have had: "I did the landings by the book and darn near damaged the plane, the Coupe does not go straight down the runway after the nose wheel hits the ground, it goes in the direction the plane is facing, in this case 45 degrees to the centerline." I admit that you really have to steer hard to keep the plane in a straight line when in a strong crosswind, but after touchdown, initial moment is flight path flown before touchdown. This is at least my experience so far. So what happened on that day when the right wing did not come down? First there is to say that the wind came really in a 90 degree from the right. 15+ knots. Approach air speed 65 miles. Now these 65 miles air speed transformed to 65 miles ground speed after touch down, because there was no head wind component. The wings develop lift well below 65 and that lift had to be dropped via a high tail and negative angle. That did work for the left wing since the initial moment of straightening the plane after touchdown reduces its speed trough the air for a sec and being on the lee side of the crosswind, it stopped flying. Not so the right side. The right wing actually accelerated through the air, producing more lift for a blink of an eye and also had the X-wind blowing full onto its surface. That lifted the wing and without a headwind , nothing was slowing down the plane , except using the brakes, which I was afraid would tip me over, so I kept riding it out. While doing so I tried different elevator deflections. In the contrary to our theory about how the proper tail height would dump lift, pushing forward on the yoke - elevating the tail - would rise the right wing even higher into the air. Pulling on the yoke , would lower the wing although I was in low tail mode. But what ever I did, I could not dump the lift of that wing via angle of attack. The wing finally stopped flying when I was making less than 40 I guess. What I did not try, but will put into consideration next time, is to approach with the left wing into the crosswind. That way I at least sit on the portion of the plane which has to come down. Tail height is important, but not a guarantee that the plane will do your landings. Proper planning of the approaches in heavy x-winds seem to be very important too. Hartmut Ed Burkhead wrote: > ----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]---- > > Hartmut, > > Please also see my other post. > > I think it sounds like your tail is drooping. You ask "Is it the Coupe or > the Couper?" I'd bet it's the Coupe. With the tail at 75" on the ground, > the wings are at near zero angle of attack and near zero lift, even with the > dihedral on the up-wind wing. That being the case, your wing WON'T lift. > > If your tail is below 72", especially if it's way below 72", you WILL get > just the kind of wing lift and control difficulties you recount. > > Twenty three years ago, when I first got into Couping, we thought that > Coupes were just squirrelly in strong crosswinds. Mostly due to Bill Coons, > it was figured out that the Coupes ought to sit ON THE GROUND in the > attitude the designer designed into them. That low angle of attack ON THE > GROUND is critical to Coupe crosswind behavior. > > If your tail is low, get new donuts and spacers and get it up ASAP. I did > it myself (and I'm very non-mechanical) in about 21/2 hours. > > Ed Burkhead > http://edburkhead.com/ > [EMAIL PROTECTED] > > -----Original Message----- > From: Hartmut Beil [mailto:[EMAIL PROTECTED] > Sent: Thursday, December 26, 2002 3:21 PM > To: Coupe-List > Subject: Re: [COUPERS-FLYIN] Re: Digest list: Ercoupe Hangar Flying > > ----[Please read http://ercoupers.com/disclaimer.htm before following any > advice in this forum.]---- > > Gentlemen. > I had my share on good Crosswind take offs and landings. > First I must tell you no fear! A lot is possible in a Coupe. > While other Aircraft might be limited by the the amount of force they can > put in on the rudders in cross wind landings, the Coupe seems to be limeted > only by your own abilities. > Of course these abilities grow with practice. > I remember my first X-wind takeoff with a 10 knot direct ( 90 degrees) > x-wind. > Did not work to well because I left the elevator trim in takeoff position as > per book and desperate as I was, I tried to steer down the runway with a > already lifted nose wheel., so I aborted and after realizing what was > missing , I forced the nose wheel down to give me the steering authority > needed. Piece of cake. > Years later circumstances will have it that I arrive at my airport on a > beautiful but windy Saturday just to find myself the only pilot to be out > there. > The wind was straight pointing at a 90 degree angle and extending the > windsock to its full glamour and left even the ends of it flutter . > I heard that a fully extended windsock indicates 15 knots of wind . What the > heck I thought, 15 knots, thats just 18 miles and reported are 25 miles for > the Coupe with claims of even more. My Coupe, well maintained as I am a > German has its tail where it should be , so no problems will come up on > landings I thought to myself. And how to take off I learned years ago > anyway. > So up I went. > The take off was already an adventure. The tail pushed hard on the plane - > it really wanted to go into the wind, and I had a hard time to keep the nose > down and steer and finally when reaching 60 I gave the plane what it wanted > and let it fly and up we went, pointing 45 degrees toward the wind - > perfect. > So I went into the traffic pattern, adjusted the plane for the Crosswind in > all turns, excellent. > Down to the final approach. I adjusted for the cross wind and found myself > pointing with the left wing toward the runway!. That seemed akward, but I > told myself 25mls are reported. If others can do it , you will to. > So I came down. Centerline runway. All perfect, just the plane was actually > pointing wing forward. When over the concrete I also realized that if you > approach in a 90 degree crosswind > your ground speed is really 65 in contrary than landing into the wind where > your headwind takes off some of your ground speed. > So there I am really making 65 down the runway and pointing forward with > the left wing. > All seems to be too fast then, I was in doubt for a moment and was thinking > for a go around, but then I realized, nothing would change, this is the way > I have to land now. > Touch down. Good , all seemed well. . The plane turned into the flown > direction, centerline, but the right wing ....did not come down, so did not > the speed. > Now I got a little concerned. I can not roll down all the 3000 ft of the > runway with the right side of the plane up and the feeling of actually > steering the Coupe only on the front wheel and the left . What the @T%$$*^. > Come down right wing! It did not come down. > I was afraid to use the brakes, because I didn't want the Coupe to get out > of balance also I found it hard to steer the plane only on two wheels. It is > hard folks. Really. Takes a lot of nerves. However, I found that when I > pulled backwards, the wing would come down and when I let go or pushed > foreward the wing would actually come up. Wow. > As the speed finally came down to .. a number I can not report, the wig came > down, the plane was acting normal again... and up I went again! lets see who > is the boss here!. > I really thought I learned ho to deal with the wind, came down for a second > landing and.. > I have to tell you guys, It is not funny to land a Coupe in a direct > crosswind at or above 15 knots and so it is surely not with other light > aircraft. > After the second landing I felt my luck was exhausted and I gave up. > Not really. I just stopped flying for the day and gave it some consideration > that no onelse - no one even tried to dare the winds. > So is it the Coupe or the Couper???? > > Hartmut N3330H > > > > > > > My book says 25mph crosswind. I've don 25 to 30,N3619H > > -----Original Message----- > > From: Ed Burkhead <[EMAIL PROTECTED]> > > >>From the http://www.ercoupe/org FAQ article: > > >Question: I rode in a Coupe on a crosswind landing and the up-wind wing > > >lifted so high I though we'd flip! > > >A few people have ridden in a Coupe which, during this yaw motion, lifted > > >the up-wind wing quite a ways -- and that ride is scary. Ten or twenty > > years > > >ago, the majority of Coupes were sitting on their landing gear with the > > >tails drooping low. Some of this was caused by aging and compressed > rubber > > >donuts in the gear (or by old Belleville springs). On many planes, this > was > > >worsened by replacing the original nose gear single-fork with a later > > >designed (and slightly longer) double-fork. > > > > > >We didn't think much of it, at first. But it was realized that this > > >on-the-ground position gives the wings more angle of attack that was > > >designed into the plane. Bill Coons of Lombard, Ill., went to an FAA > > >engineer in Chicago and got shims approved for the landing gear and he > > >passed the technique around the club. Added into the shock absorber > stack, > > >the shims return the on-the-ground attitude of the Coupe to the designed > > >angle of attack in spite of compressed rubber gear donuts, aging springs, > > or > > >a longer nose gear fork. Subsequently much of the fleet has gotten > > >maintenance and/or shims as needed to raise the tails on the ground to > the > > >designed 75 inches and no-lift angle of attack. > > > > > >With the tail at the right height, the Coupe's crosswind landing behavior > > is > > >the best in the industry, bar none. > > > > > >Question: How high a X-wind can a coupe handle? > > >Like most planes, pilots report having landed in crosswinds much higher > > than > > >the demonstrated crosswind component. Some Coupe pilots say they don't > > think > > >twice about 30 kt. direct crosswind component, others claim to have done > > >even higher crosswinds. In practice, many Coupe owners are comfortable > > >flying in crosswinds that keep them on the ground if they were flying > most > > >other light planes. Smart pilots first work their way up to the > > demonstrated > > >croswind component listed in their owners manual. First they get fully > > >competent at that level, and only then experiment as their own skill and > > >equipment allow. Be sure your tail is at or very near regulation height > of > > >75 inches for good crosswind behavior (see detailed discussion below). > > > > > >Ed Burkhead > > >http://edburkhead.com/ > > >[EMAIL PROTECTED] > > > > > >-----Original Message----- > > >From: John Jameson [mailto:[EMAIL PROTECTED] > > >Sent: Wednesday, December 25, 2002 8:46 AM > > >To: Ercoupe Hangar Flying > > >Subject: [COUPERS-FLYIN] Re: Digest list: Ercoupe Hangar Flying > > > > > >----[Please read http://ercoupers.com/disclaimer.htm before following any > > >advice in this forum.]---- > > > > > > > > >merry ERCOUPE xmas everyone!!!! > > > > > > my question is that a 415c coupe i am flying has a little bit of a low > > >tail (63 inches). i haven't got around to putting spacers in to raise > the > > >tail. it flies and lands great. the "squirrley" landing characteristics > > of > > >a low tail are supposed to be on crosswind landings. > > > > > >can someone describe what i might be in for in a crosswind landing with > > this > > >low tail?.... thanks jm jameson > > ========================================================================== == > == > To leave this forum go to: http://ercoupers.com/lists.htm > > ========================================================================== ==== > To leave this forum go to: http://ercoupers.com/lists.htm ========================================================================== ==== To leave this forum go to: http://ercoupers.com/lists.htm
<<attachment: winmail.dat>>
