Okay, I spent a couple of hours this weekend messing around with approach speeds, trying to shorten up my landings.
Here's a synopsis of my experiences, based on full fuel and 130# of crew. First of all, every mph over 75 over the fence costs me 100 feet of runway. Second of all, I need to disabuse myself of any notion that I'll land a 415D without split elevator like a 150 or 172, ever. Forget it. Ain't gonna happen. Those 'bird on a fence-post' landings aren't the Ercoupe way. Between the ground effect floatiness and the minimal elevator authority, the ingredients aren't there. Third, these Cleveland brakes actually work pretty well and are worth using. Fourth, they aren't kidding about the margin between floating and sinking being very small. Fifth, they aren't kidding about running out of 'up elevator' to flare. Sixth, there is a substantial difference between a power-off glide and a power-on glide in that the former exacerbates both the sink and lack of pitch control mentioned before. I started by really paying attention to nailing 75 MPH on final. This is not that easy with the old-style trim. I found just by doing that, and by not letting it creep up or down, I shaved 500 feet of my landings. Still a bit long, though. So I started easing back the approach speed, and found that I did get shorter right up to the point where I ended up in a power-off glide around 72 MPH. On short final, I observed that the runway was coming up to smite me. I initially thought I might 'save' it with a little power, but I was on VERY short final so decided to go for full power and a go-round. It was the right thing to do. So I decided to focus on 75 MPH, but no more, still not much less. Particularly with power off. Power-on, there seems to be more lattitude. Later on, I let the speed bleed off a bit with power on over the fence. I actually got as low as 70, then discovered, to my dismay, that the yoke was now full back but that I was poised to land on all three wheels at once. A hair of power and she went on the mains first, then right to the nose gear. There's that unmodifed D-model limitation! So, my conclusion is that in ordinary circumstances, 75MPH is a good safe number, and that any float that results is a mere annoyance that is a good safety trade-off when there are 2500 feet of runway available. First choice in the absence of the latter is to try and stay with the flatter 75MPH glide over friendly terrain such that the floating takes place prior to the numbers. If that's not an option, then no less than 72 is acceptable, with the understanding that a bit of power may be needed to flare is in order. And, at least for my plane, no less than 72 MPH, ever. Greg
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