Donald.
If you can fly the approach at 80 MPH down to the runway and initiate a normal flare, then the airspeed indication is too high. Thus making you fly too slow. I had this in my brothers Coupe. the airspeed indicator was indicating 20 Miles too much. In fact , the airspeed needle was not even pointing to Zero when standing still, but rather to 20 miles. That explained the offset. After installing a new airspeed indicator, the plane would be controllable exactly to the numbers. I assume your airspeed meter is old enough too to be replaced or if the instrument appears good, then the static system is causing wrong indications. All that makes you fly too slow, while the instrument showing 70 gives you the illusion of having a great margin, but you probably are flying then 50 MPH. With two people aboard, close to gross weight, it will leave you 4 Miles before the published stall speed. When you then flare you will lose speed rather fast and the plane will not only sink down gentle, but drop to the ground. No problem when you are 1 feet off the ground . From 3 feet on this drop will be pronounced. Let it be 6 feet and you will feel it like you're describing. The hint here is flying down to the runway at 80 miles an hour. If I did that with my Coupe, I can not settle don the plane. I rather float for half the runway until the speed dropped off. Tell me if I am wrong, but am convinced your airspeed meter is off. These instruments don't last long. Even unused they get out of calibration. So no need to do stalls to proof the wrong air speed indications. Get the system checked. Or if it is obvious as in my brothers plane, replace the airspeed meter. Hartmut To: [email protected] From: [email protected] Date: Mon, 15 Mar 2010 13:18:34 +0000 Subject: [ercoupe-tech] Re: "Falling Out Of The Sky" at 72 mph Very good William thanks for the guidance. I am going to read this several more times to "get it right". I am having a landing problem with my coupe, although I have only landed it 12-15 times with an instructor aboard. My problem is that I fly approach at 80, have no problem dropping directly to the end of the runway, pull back to arrest the drop and everything is going like textbook landing. Then at about a couple feet above the runway (guesswork, maybe 1 to 3 feet) while I have a beautiful flare going on, all of a sudden the bottom falls out and I drop like the landing gear should be broken off! I have made maybe 3 squeakers, but the rest are terrible! I stop in a short length, I am amazed at how short a field I would need to land in. My instructor claims I am not using enough up elevator, but I think I am just too slow in using it. I never had such a problem with other aircraft, but remember I am old, and it has been 17-18 years since I last flew. My tail height is about 6 inches low, I have not corrected that yet. Any helpful hints anyone? --- In [email protected], William R. Bayne <ercog...@...> wrote: > > > Jerry, > > Your G model has (or should have) the "split elevator". > > If the air speed indicator is accurate and if the plane is rigged > correctly it WILL NOT "fall out of the sky about 72 mph". That's well > above the "high sink rate" range. As a first step, I suggest you take > a GPS aloft, slow the bird to 73 mph indicated, and compare the two > readings. The Approved Flight Manual for Models 'E' & 'G' on p. 11 > showed a "true airspeed" of 60 mph when 56 mph was indicated, 70 mph > when 67 was indicated and 80 when 78 was indicated. > > Landing the various coupe models at the speeds Ed stated is not rocket > science, but it does presume an accurate air speed indicator and > proficiency in accomplishing an appropriate sequence of events. In my > own case, I had absolute confidence in the Ercoupe Instruction Manual > and "just did it"; but some are more comfortable having these things > demonstrated before they can proceed. > > As a rule of thumb, the indicated airspeed is higher that the truth > below 100 mph and lower than the truth above. For all values above > "minimum speed" the error is 3 mph or less. That's not enough to get > anyone in trouble that has any "feel" whatsoever for the aircraft in > flight. > > The "stall" in an Ercoupe should be a gentle drop of the nose to pick > up a few miles an hour and altitude loss should be minimal. If the > yoke is moved back too rapidly near the minimum speed, the resulting > "whip stall" is much more abrupt and more altitude is lost. This is > something best worked out at altitude and not just above the runway. > > Should a low time pilot "balloon" (suddenly climb and find themselves > 5-10 feet off the runway with little forward speed), immediate > application of full power restores lift to the wings with minimum loss > of altitude. Hesitation, however, will likely result in a hard landing > with possible damage. > > Most of us have a WW II training base with long runways within flying > distance that is now municipally owned and operated. Go there and make > any necessary arrangements to practice slow flight and touch and goes > with plenty of hard surface available. > > With a 5,000' runway, practice slow flight...holding the bird one foot > off the pavement at the slowest speed possible. Before the coupe can > "stall", it will sink. So long as you can keep the bird from touching > the runway surface with the yoke at a constant speed you absolutely > cannot stall while in "ground effect" at that speed. Keep reducing > that speed in two mph increments and eventually you will be able to fly > an approach arresting descent one foot off the runway and fly the > length of it without touching down. > > Next time around, at that same constant speed move the yoke back a bit. > If the plane goes up, you weren't flying slow enough. If it sinks to > the runway surface, it will be your slowest, smoothest landing ever. > At the moment of touchdown, THAT is YOUR plane's "minimum speed" > occurring just when you want it to...at touchdown. Jot it down for > future reference. > > If you go back up to pattern altitude and establish that "minimum > speed" you will probably find that you are sinking like a stone. > That's why the landing approach is not flown at that speed in an > Ercoupe. The G model has a power off stall speed of 56 mph. The low > speed warning cushion (spring) is supposed to be felt at 60 mph. > > The 415-D Approved Flight Manual on p. 10 suggests an approach speed of > 75 mph and its power off stall speed is 58 mph. The manual for the E & > G models refers you to the Ercoupe instruction Manual, and it suggests > approaches be flown between 60 and 70 mph. At or near 1400# the higher > value is more appropriate. > > Remember that 70 mph (true) is your "Best Rate of Climb" (see Climb > Data, p. 10 of the Approved Flight Manual for Models 'E' & 'G'). At > that speed, anytime you move the yoke back gently the energy of the > "excess speed" is converted into altitude and the plane's altitude > increases even as the forward speed decreases. Your speed for "Best > Angle of Climb" is even slower at full throttle. This is simply NOT a > speed range where you are tempting fate so long as you understand how > to trade speed for altitude and altitude for speed. This is a > fundamental skill all should practice, but If you are more comfortable > flying the approach at 80 mph, do so. The speed of the approach is > relatively unrelated to the speed at which touchdown takes place. > > Most find it easier to establish a "stabilized approach" (constant > airspeed and engine rpm while maintaining a relatively constant rate of > descent with the yoke) until just before touchdown. When you cross the > runway threshold at 5-10' up reduce power and SLOWLY move the yoke back > only as fast as does NOT make the bird climb. The idea is to slowly > increase drag with higher and higher angle of attack holding the plane > one foot off the pavement and when ALL the "excess speed" is thus > scrubbed off the plane will gently sink to a very smooth landing. > Unfortunately you may be using 4000'+ of runway to do it. > > Now do this again, establishing the one-foot-off slow flight. > Simultaneously close the throttle and move the yoke back to keep the > plane "balanced" at that one foot off. Once THAT coordination is > worked out, reduce engine rpm on final (if necessary) to cross the > "fence" at 70 mph. This should make it possible, with practice, to > land and make most second turnoffs WITHOUT BRAKES! > > Minimum speed at the moment of touchdown is desirable because (1) the > plane can't lift off the runway again without power, (2) the wear on > the tires (the "chirp" at touchdown) is less because they have to "spin > up" only to the lower speed, and (3) brake puck and disk wear is > reduced so much that once the technique becomes "standard operating > procedure" for you there will likely be the need to land fast and hot > about once a month in order that the puck remove the accumulated rust > from disuse. > > Operating a properly rigged Ercoupe in this manner is "stall proof" > except in high, gusty crosswinds. For high, gusty crosswinds, add 5-10 > mph to your approach speed, but chop the power over the runway > threshhold at 5-10' up and do everything in the preceding paragraph > exactly the same from that point on. Having extra speed at or after > touchdown is a PROBLEM, not "insurance". Should a gust suddenly lift > the plane off the runway, immediate throttle restores lift to the wings > and returns to the pilot the option of go-around or a smooth landing > (remaining runway permitting). > > Until this level of proficiency is developed (and more than a few that > will "instruct" in a coupe don't have it to pass on), your are not > master of the Ercoupe. Until you are master there is risk. Maximum > safety depends on owners or operators reducing that risk to zero with > appropriate priority. > > Your metal wings reduce your useful load, but they have no meaningful > effect whatsoever on your approach speed or minimum (touchdown) speed. > > Hope this helps. > > William R. Bayne > .____|-(o)-|____. > (Copyright 2010) > > On Mar 14, 2010, at 22:43, Jerry Ward wrote: > > > > > > > You guys all keep talking about landing your coupe at such slow speeds > > - I have a metal wing G-model and I have trouble getting it to land > > under 75mph.Ê I sure am jealous of all of you that can land slow.Ê If > > I were to try that I would break my landing gear off.Ê It starts to > > fall out of the sky about 72mph.. And I do mean fall fast.Ê Jerry in > > the Great Northwest. > > Ê > > Ê > >> ----- Original Message ----- > >> From: Ed Burkhead > >> To: ety > >> Sent: Sunday, March 14, 2010 7:45 PM > >> Subject: FW: [ercoupe-tech] Kim's Ercoupe > >> > >> > >> Ê > >> > >> Maybe this is more readable: > >> > >> Ê > >> > >> As I said a couple of days ago, this gave these results: > >> > >> Ê > >> > >> 13û up travelÊ 48-52 mph landing speedÊÊ > >> > >> 415-C and 415-CD > >> > >> Ê > >> > >> Ê > >> > >> 9û up travelÊÊ 55-60 mph landing speedÊÊ > >> > >> Ê > >> > >> 415-D and on earlier models > >> > >> ÊÊÊÊÊÊÊÊÊÊÊÊÊÊ with 9û elevator limitation due > >> > >> ÊÊÊÊÊÊÊÊÊÊÊÊÊÊ to using the 1320 pound STC > >> > >> Ê > >> > >> Ê > >> > >> 20û up travelÊ 48-52 mph landing speed > >> > >> Ê > >> > >> 415-E and all later models AND > >> > >> ÊÊÊÊÊÊÊÊÊÊÊÊÊÊ earlier models with split elevator > >> > >> ÊÊÊÊÊÊÊÊÊÊÊÊÊÊ installed via STC or field approval > >> > >> ÊÊÊÊÊÊÊÊÊÊÊÊÊÊ on a form 337 > >> > >> > >> > >> > _________________________________________________________________ Hotmail: Trusted email with powerful SPAM protection. https://signup.live.com/signup.aspx?id=60969
