Behind the Curve 

Mark, are you still im deutschland? Oder back in the US?

@@THEDonMaxwell Hi Don! I happen to be in VA for about a week, then back to Deutschland. Hope you are well and having fun!

@@mch979 I've just emailed you at yahoo.com

Good question. In this particular case I knew that the tire was soft but not completely flat. And I knew that there's not much weight on the tailwheel--less than 150 lbs. AND I knew from having had the tailwheel tire go completely flat once when I had to taxi from grass up over the sharp edge of the concrete ramp at the Udvar-Hazy Museum that the airplane steers well with no air in it at all. So I didn't expect any difficulty. It was a calculated decision, and as you see in the video, the landing went well as far as the tire was concerned. The problem was landing with full flaps and insufficient power. And even that wasn't really much of a problem.

Thanks for the report! I don't remember why I chose the reddish color. You're right that white would have been easier to read--although white with a black outline would be easier no matter what the background color happened to be.

They wear and tear I fly a 1946 7ac champ it's common, due to back weel coming down a bit hard on 3 pointers

Another excellent question. I don't remember why not a wheel landing--but it probably had to do with ground speed. With full flaps my Searey stalls at about 36 mph, so maybe that influenced my thinking at the time. If the tire had been completely flat I would have done a wheeler no matter what--although at that time my brakes didn't hold well enough for a wheeler to have made much difference. A few months ago I replaced the wheels and brakes with new ones, and now I can keep the tail up to a dead stop--so NOW I'd definitely choose a wheel landing.

Great question. It was both! I was doing fine, flying along just above the runway in ground effect--which was also slow flight, just faster than the stalling speed. In true "slow flight," to slow down without losing altitude, you have to add power, and the slower you get, the more power you need. The nose is pointing up and gets ever more up as you get slow. That's often called "flying on the back side of the power curve" or just "behind the curve." Eventually, you can get so far "back" that the engine doesn't have enough power to keep you in level flight. Well, recently I'd been experimenting with using full flaps for landings, changing from 20 degrees to 30 degrees just before rounding out over the runway. And although I'd have known better if I'd bothered to think about it, this time I just went to 30 flaps without adding power--but to keep flying I had to pitch the nose up to compensate for the added flap angle. That, of course, slowed the airplane to the stall speed and it quit flying abruptly and fell--maybe 1 foot--with a thump. Stalls are benign in my airplane--so if I had been flying well above the ground, the nose would have dropped to break the stall and I could have gone on flying even without adding power. But at 1 foot, it just went thump. (I think the FAA now recommends exiting a stall by adding full power as well as lowering the nose. I do that as a rule; but it's not always necessary, especially in airplanes as stable as mine.) The effect of increasing flap angle is especially interesting in amphibians because increasing the flap angle tends to lower the nose, and nose-low is generally not a good thing during a water landing because the water drag can cause the nose of the floats or hull to submerge. That's likely to send you swimming. On land, submerging is a lot harder to do because the ground resists it. On water, you need the floats or hull to be at a certain angle to the surface so that the water drag is as little as possible. So you have to be more wary of changing the flap angle. (I think. I'm not an aeronautical engineer.) As for the two terms, I think I squeezed both "stall" and "behind the curve" into the titles--anyway, I meant to.

I just realized that I hadn't answered Guy's excellent question about an AOA. My plane has an AOA (Angle Of Attack indicator), but I've never looked at it during a landing. That's mainly because I'm concentrating on getting the landing right, and I already know I'm going to stall. Now, though, I'll try to point a video camera at and see what it tells me.