I made my gear legs 1/4-inch wider than the stock Diehl gear legs and 1-inch longer than the tail dragger version. My theory is the extra length is needed to compensate for the extra angle to get the needed 3-inch set back and to get a more level stance on the ground. The 1/4-inch extra width will add about 8% additional stiffness to compensate for the extra length. Some extra twisting comes into play due to the boomerang shape. That extra torque would be about 100 pound-feet at max gross. That seems nominal to me. I don't know the math to actually calculate the spring constant and don't have the lab facilities to empirically measure the various combinations of gear leg shapes. My approach is to duplicate the performance of the stock gear legs and adjust for my particular KR-2 configuration for 800 pound empty weight and 1250 pounds max gross.
Sid Wood Tri-gear KR-2 N6242 Mechanicsville, MD, USA ------------------------------------------------------------------------------------ I got the same legs, but thinking of leaving the same thickness but using the full length of the Grumman blanks for prop clearance on my tail wheel. Just waiting on some cast brackets from Steve so I can finished them off. Do think the Grumman leg thickness would be too much? Mark L commented on leaving them as is as they are longer, Any finished and flying these legs care to comment?? Phil Matheson. Australia -------------------------------------------------- Update on moving the main wheels on my KR-2: Removed the main gear fiberglass struts. These are supposed to be used for a tail dragger version. Obtained Scotch ply Grumman Cougar blanks from Fletch Air. _______________________________________________ I've been thinking on this as well. I suppose one could leave them the full inch thick but make them narrower (i.e. not as wide) if they were too stiff. Leaving them longer (which I also plan to do) will offset some of the stiffness, and additional stiffness will probably be a good thing given the higher gross weight KRs seem to be built to these days (mine will be 600kg/1320 lbs). I don't know enough about the engineering of springs to make an informed decision here, so the experience of others will be welcome. Cheers, Tony ----------------------------------------------------------------------------------------- I have installed the Grumman legs on my KR2-S. I kept them the original length and thickness but trimmed them down in width. Minor deflection as the plane sets now. Fuselage, tail, controls and motor mount (weighs 198 lbs). I have also used the fiberglass leg for the front gear. With me in the aircraft (250) gross so far at 448 lbs the gear deflect about 5/8". I expect a total of 1" deflection as engine, wings, fit out and fuel are added and dispersed across the 3 legs. I can send more detail and measurements if your interested. Dan Prichard -------------------------------------------------------------------------------------------- > >I have installed the Grumman legs on my KR2-S. I kept them the original length and thickness but trimmed them down in width. That is exactly how I would do it. Our planes are heavier these days anyway, so some extra thickness is not a bad thing. Mark Langford ML at N56ML.com http://www.n56ml.com *************************************
