> I am in the process of changing my 6 x 30 inch speed brake. It has 12, 2" holes in it. It does ok in terms of slowing the KR down, but it doesn't do much to lower the nose attitude on approach. Has anyone compared the two type of SB with respect to nose attitude on approach? If so, please enlighten me. >RV +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Is your wing incidence set to 3.5 degrees per the plans? To get a more nose down attitude on approach you need to add more drag. My brake (9" X 30") gives me a nice over the nose view all the way down to the flare. I loose the view when it drops into a three point attitude. That much drag also gives me a rather high decent rate, somewhere in the neighborhood of 800 or 900 fpm. I carry a bit of power until I get close to the numbers and then I cut the power and attempt to slow it down another 5 to 10 mph before I get into ground effect or it floats forever. I approach at 80 smph indicated. The size of the brake is determined mostly by the ground clearance you have. I have plenty with my 30 inch gear legs but even then my brake comes close to tall grass. Tri-gear might be to an advantage here. Moving it forward would help some with the clearance but I'm not sure how it would affect handling. I'm inclined to want to keep the drag forces behind the center of lift to help stabilize the aircraft rather then in front of the center of lift. If the drag loads are balanced side to side and basically centered and parallel to the direction of travel you probably don't have a problem. The brake behind the center of lift and C.G. would be acting more like a "drogue chute"(sp?). At least that's how my pea sized brain pictures it. Your brain could very well be larger and give you an entirely different view. :-)) As to which type of brake is better, the one with the most drag. Now all we have to do is figure out which one that is. Maybe a test rig hanging out the car window could tell us. Anybody up to that? Better yet, maybe one of the engineer types could just give us the answer. I did a quick search on the web and looked in the Tony Bingalis books but no luck. Larry Flesner
