Bart. Lengthily post. I may not understand all of it.
My first thought was that a spin close to the ground is very unlikely to develop. You will hit ground first. That's the way you should land anyway. May be not that harsh of a stall, but close to it when landing. Brings me to the second thought. When you are able to hold the nose wheel off the runway for quite some distance - in a Coupe, you are simply landing too fast. But good advice to air break rather than Goodyear-puck brake the plane. The part about the trim tab influencing landing or stall characteristics is not really clear to me. To me the trim tab is mainly used to keep the elevator in a certain angle, resulting in a certain altitude per power setting. The trim tab is small enough not to represent another flying surface. I did quite a few stalls in my coupe and can say that it makes no difference how you trim the plane. You'll end up full elevator up in any case for the stall. In case you are trying to stall the plane by lets say slowing down to below flying speed at a certain altitude, you won't end in a stall, your Ercoupe simply would not hold the altitude and start sinking like a brick. A good steerable brick though. As for the spins, The Ercoupe is characteristically incapable of spinning. That is proofed in a wind tunnel test with a model. Even when intestinally put in a spin, the model would just get out of the spin by itself. see also: http://www.ercoupe.info/index.php/Main/WindCanalTest Hartmut ----- Original Message ----- From: robertbartunek To: [email protected] Sent: Saturday, May 10, 2008 4:24 PM Subject: [ercoupe-tech] Stall/spin potential-danger At Sun-n-Fun, I watched the C-54 land and the guy held the nose wheel off the runway for quite some distance down the runway. Reminded me what we used to to to aerobrake airplanes in the Air Force and how we used to enhance elevator effectiveness to hold the nose up longer on landing rollout and induce a lot of aerodynamic drag. Saves the brakes, you know. The caveat is that there may be a way to get a higher angle of attack and/or full stall in the Ercoupe, if conditions are right, and subsequent autorotation (spin). Elevator effectiveness is increased significantly, at least in the C/D with the bigger trim tab, if you trim full nose down. You can try it if you don't believe it on landing rollout if there is no crosswind (need that nosewheel on the ground to steer). You can hold the nose wheel off the runway significantly longer with full nose down trim than you can if the airplane is trimmed for landing. The dynamics are, with full nose down trim, the elevator trim tab moves upward, increasing the effectiveness of the up elevator input. The danger is, if you are trimmed full nose down and practicing stalls, you might exceed the design certification test parameters, get a full stall and departure and end up in a spin and become a test pilot. Now, before some jump on me saying the above fearing that someone might go out and try it, I am doing it as a matter of promoting flying safety because there may be a way to spin an Ercoupe and everyone should be aware of the possibility. I'm not saying to do it, the same as I am not saying to push the yoke full forward and add full power to see how fast you can go before the wings diverge and come off, or to put a gun to your head and squeeze the trigger to see what happens. I am just issuing a warning that there might be a subtle booby-trap that can possibly get you in trouble. Bart
