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ultra smoothe glassy water landings danger

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ultra smoothe glassy water landings danger

Unread postby CFII » Wed Jan 02, 2013 3:32 am

I was finishing up my latest BFR with some glassy water landings in a SuperCub from CubCrafters (which can totally spoil you) and the CFI said he'd had flight students that had actually touched down on glassy water so smoothly they didn't know they were on the water for a "minute"!

Even if the time was possibly somewhat exaggerated, it shows the usefulness of having enough sink rate so that the water can be felt upon contact.
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Re: ultra smoothe glassy water landings danger

Unread postby RKittine » Wed Jan 02, 2013 8:05 am

Thought it is hard to believe that the drag and spray would not be noticable, but then the higher speed and lower sink rate, would surely result in a LONG landing. I agree that a sink rate that lets you know that you have come in contact with the water is prefered.
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Re: ultra smoothe glassy water landings danger

Unread postby Tim McCormack » Wed Jan 02, 2013 10:14 am

Bob, I'm beginning to worry. You're starting to talk to yourself. :acute:
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Re: ultra smoothe glassy water landings danger

Unread postby RKittine » Wed Jan 02, 2013 11:23 am

Hi Tim,

I was responding here a little differently than to the same post on the SPA Forum. Never had any Seaplane Students that landed that smoothly when practicing glassy water landings, but CFII has a good point.

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Re: ultra smoothe glassy water landings danger

Unread postby CFII » Wed Jan 02, 2013 1:39 pm

An extreme example for sure but, when power is at a certain level there can be very little of that aircraft's floats touching to cause arrest of sink rate, due to its high lift configuration and thereby very little spray out laterally, if any. Forward fixation by the pilot would take care of the rest in just the wrong situation....
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Re: ultra smoothe glassy water landings danger

Unread postby RKittine » Wed Jan 02, 2013 2:51 pm

I would agree with that. When I teach glassy water landings I teach power off on final approach until crossing the LVR and then adjust pitch to the picture they have been taught, while bringing in power to a specific setting rather than an air speed. If the student stays with those two things, the resulting sink rate gives them enough physical impact for them to tell that they are on the water and can reduce power and put in full aft stick. When they chase airspeed, never are never consistent with what they get.
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Re: ultra smoothe glassy water landings danger

Unread postby skimmerone » Wed Jan 02, 2013 3:40 pm

My 2 cents. At least for the Lake and Skimmer. Attitude sets the airspeed and power controls rate of descent. Before we get near the water, or on the way to the water, I have the student set up the correct attitude using visual references like the horizon and longitudinal reference points. Nose just slightly up from level, using about 18 to 20 inches of manifold pressure. Basically, slow flight. Then we hold the attitude and airspeed and reduce the power slowly until we get a 200' per minute rate of descent. Once that stabilizes we check the manifold pressure and remember it. Most Buccaneers and Skimmers end up at close to 58 mph and 16 inches of MP. This last figure will change with load and density altitude. For the actual landing, we descend without power to just before the last visual reference, then add power to the known setting, then adjust the attitude which adjusts the airspeed, or do it simultaneously. But NEVER adjust the attitude first. At this slow airspeed, if we bring the nose up first, we are immediately going to lose airspeed and it is already slow. Power in first to prevent a sink rate from starting. It takes forever to fly out of a sink rate at reduced power. It is the last thing we need to have happen when we don't know where the surface of the water is. Everything should be set up before we cross the last visual reference. There have been many aircraft sent to the bottom because they were out in the middle of a large, glassy lake attempting to set up a glassy landing with no last visual reference at all.

Once contact has been made do not make any power changes until you are absolutely positive you are on the water and you will feel it rather than see it, since any spray is far aft. The best indication is the airspeed dropping off due to more and more friction on the hull which is displacing more and more water. Remember that until this happens you still have flying speed. With the pusher configuration of Skimmers and Lakes one must also be careful not to reduce the power too rapidly where the sudden lack of nose down thrust changes the attitude to nose up and you find yourself flying off the glassy water with no power and deteriorated airspeed and no idea how high you are above the glassy surface.

One little trick that I have never really had the guts to try is using the little mirror on the wing float - it is there to check where the nose gear is (up or down), but you could if you concentrated hard enough watch the reflection of the hull on the glassy water get closer and closer. It is smarter to look out at the horizon, though...and the gauges.
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Re: ultra smoothe glassy water landings danger

Unread postby RKittine » Wed Jan 02, 2013 5:21 pm

Sounds like about the same procedure with the exception of the thrust issues in a Lake / Skimmer and the MP verses just a Tach. 1600 RPM with correct pitch would give 200 FPM down in the Chief, which worked well and related to about 50 MPH which for that little plane was fine.
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Re: ultra smoothe glassy water landings danger

Unread postby Tim McCormack » Wed Jan 02, 2013 5:34 pm

Bob, my bad. I thought you posted the original message and then responded to it. I don't know if I can stop worrying, though. ;)
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Re: ultra smoothe glassy water landings danger

Unread postby RKittine » Wed Jan 02, 2013 6:00 pm

No, CFII did. The cold is getting to me though.
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Re: ultra smoothe glassy water landings danger

Unread postby de Haviman » Mon Jan 21, 2013 10:35 pm

Why is a smooth touchdown on glassy water dangerous?
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Re: ultra smoothe glassy water landings danger

Unread postby CFII » Tue Jan 22, 2013 4:09 am

de Haviman wrote:Why is a smooth touchdown on glassy water dangerous?


It is when TD is so smooth that the pilot doesn't know he's on the surface and is taxiing at high speed for a prolonged period of time.
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