The designer during the design and structural analysis process considers the holes, both locations and diameters, and load being applied to determine the final size requirements.
To continue the design process of the spars, the designer determines the landing gear strut load conditions. ++++++++++++++++++++++++ The sensible approach to building an airplane (if you really must) is surely to buy plans or a kit from a reputable designer and build the airplane according to plan. Fact is, few of our species want to go this way, including (with respect) Ken and Stu - in fact, if they had followed this sensible logic when they each wanted an airplane, the KR would never have been born. No matter how strong your feelings may be, getting wound up, insulting and cussing will not achieve anything other than cause rifts - and silence those that already say very little (generally the smart ones who's input we really need). It is sound advice that tells us NOT to mess with things unless we know precisely what we are doing, cannot fault that. For me, even better advice is where to find the skills you need to come over and help you mess with whatever you want messed with. I am sure that is what R&R did, there is just no way they used the core design "as is" for all the products. What they came up with has proved to be adequate - not sure when Jim Marcy got involved, but if they did not know, they sure found someone that did, just like we can. To get a neat KR off the ground is going to cost at LEAST $10k plus a few years of dedication. Another $2k ?? for the right skills check the changes that make it perfect for you is a bargain. The original KR was a copied from the Taylor Monoplane (designed in 1956, 1st flight 1959). I don't know what was available in the way of epoxies, polystyrene, urethane, Dynel etc. 10 years earlier, but we can be sure that when the first KR was conceived, Rand and Robinson changed more than just the name. They seem to stay with the basic configuration, dimensions and wing section, but they took off the blinkers - history says that even their U control model airplane experience came into play - I think this is wonderful, they were true leaders in experimental aircraft. The original Monoplane had a fixed u/c similar to that on a DH Chipmunk, but the KR1 rev 1.0 emerged with a retractable landing gear. A clever concept, but one resulted in many holes being bored in the centre section spar caps for the various pivots and locks. I am sure they did the necessary and "messed with it some" - none have ever failed. This 500lb Monoplane evolved along the same basic structure to become a 1,000lb, two seat, 200 mph (up to) airplane. Most of the completed airplanes have been stretched and widened with more power added and a higher gross weight. I have little doubt that John Taylor engineered (and probably tested) the primary structure to good old British WWII standards, but I sincerely hope that R&R messed a bit with the structure on the way to the KR2. The true contribution by R&R was the concept, the materials and method revealed to the homebuilder - FLEXIBILITY. Maybe that is why less that 120 Monoplanes were ever built, but 20 times as many KR's are flying (or in the pipeline). I am NOT trying to get up anyone nose here - just make the point that our kind (the species that will opt for a KR above all other designs) aspire and dream about how it will ultimately look - different - that is the very essence of this design (concept) and it gets worse every time another great looking KR takes pops up on my screen. . Telling them to build it like it is and leave well alone, takes (for me) a bit of the spin out of the airplane. I bet that each flying KR owner is very happy with his unique, very own airplane - after all, he made it that way. If he is unhappy with some aspect - he will soon take it out back and add a belly flap, nose gear, whatever. It is a scary thought that some builders may have unwittingly done something silly that will someday hurt them - I would hope that this forum will go a long way to preventing that. I have little doubt that the originators were responsible in what they did, and that the present design is adequate (structurally safe), but like anything, it can be improved. It is this builder's intention to change everything that does not suite or appeal to his vision - but to ensure that each change is scrutinized and approved by someone competent. Test wing spars will be built (using white pine, builder's ply and carpenters wood glue) and loaded to failure. It can be done in a weekend, costs very little, gives some practice, and settles concerns. Yes, I know there is a bit more to it than that - this is just one for instance!! Have a great Sunday Steve J
