Mark Langford's KR2S Project Page

KR Design History

revised Oct 1, 1996

In the late 60's Ken Rand and Stuart Robinson were working as flight system engineers for Douglas Avionics. Ken was working as an electrical engineer, having previously worked as an autopilots project engineer, while Stu's degree was in aeronautical engineering from Northrop University. They were two of the guys at the end of the DC-8, 9, and 10 assembly lines responsible for correcting some of the nits and picks in various systems before delivery to the customer.

Stu had decided to build an airplane, and began looking for a partner to share in the effort. Ken seemed a likely candidate. He had grown up with the airplane bug, sketching aircraft designs since childhood. He had been into R/C models for years, and had already built a glider. He was a bit of a daredevil as well, having done some time racing motorcycles in cages in Atlantic City, among other things. No doubt who the test pilot would be.

They both wanted to build a fast, inexpensive airplane which was also economical to maintain. Several designs were considered, and plans were bought first for the Jeanie's Teenie and then the Taylor Monoplane. The Monoplane was more to their liking, but would require some modification to fit their needs. A cooperative redesign effort ensued, with virtually no dimensions left untouched. Only the basic fuselage structure, airfoil, and powerplant were retained. The tail shape was Stu's, and came directly from the big DC-8s parked on the ramp outside his office window. The landing gear was designed by Ken, after seeing similar gear on a Dewey Bird at Santa Paula airport.

Construction began in 1968, with both Ken and Stu building an airplane each. Stu was progressing faster, until he met a girlfriend who would later become his wife. This development allowed Ken to complete his airplane first, and it was registered N1436. First flights were in the Spring of '72. Ken was a low time pilot with only about 80 hours at the time, and had borrowed Stu's Curtiss to get some taildragger (tailskid, actually) time. On the first flight of the KR, Stu and three others flew chase in a Stinson, but didn't get to see much of the KR1. It was much faster than either of them had anticipated! That first landing was a real greaser. It looked as though he had done it a thousand times.

Ken also flew to Oshkosh in '72, where his KR1 was awarded Best Aircraft Application of Materials because of its composite wing construction. Ken's and other early KR's used Dynel fabric rather than fiberglass as the covering material. The composite wing had been Ken's idea. Stu, being the more conservative of the two, would have preferred a more traditional fabric covered wooden wing.

Plans were offered for the KR1, priced at $15 a set. Popular demand soon dictated a two place version, and the KR2 was quickly designed. It featured a wider cockpit, almost two more feet of length, and about four more feet of wingspan to handle the extra load. The KR2's first flight was in April of 74.

Stu sold his interest in Rand Robinson Engineering in 1979, and moved to northern California. He already had five acres of land about 60 miles north of Yosemite, and felt it a more desirable place to raise his children than L.A. He and his wife built a new home, then he went on to build several more in the next few years. He now works as an electrical engineer for a large limestone and dolomite mining operation, and is quite content with his move.

Ken was killed in his KR2 a short time later while flying over Cajon Pass in what was apparently a bad weather / low fuel accident. Ken's wife Jeannette became owner of RR overnight, and stepped up to keep the plans and parts coming. Much of the engineering needs are handled by Bill Marcy of Denver, who's been helping out since early '79.

To date, almost 6000 KR1, 9200 KR2, and 760 KR2S plan sets have been sold. 1200 KR2s are estimated to be flying, with 10 KR2Ss now in the air worldwide (this was 1996...many more now). Much of the development work done on KR's is now done by the builders themselves. KR builders tend to be innovative, which leads to some interesting modifications. Some of the mods that work eventually creep into the plans. The KR2S is a case in point. Many builders who'd heard of the pitch sensitivity and tight cabin of the KR2 began to build an enlarged version, with the length determined by the most commonly available longeron material. The result is a KR2 that is stretched 2" between firewall and main spar, and 14" behind the main spar. Higher gross weights dictated more wing area, with the new standard becoming the Diehl wing skin. Those who plan to carry passengers commonly stretch the cabin width a few inches, although 1.5 inches is the limit if you still want to use RR's premolded parts.

Asked it he would change anything in the KR2 design now that several hundred are flying, Stu mentioned stretching the fuselage length and height, as well as adding a little more wing area. Interesting enough, that is exactly what knowledgeable builders have been doing, and as the KR2S plans now reflect. He also thinks that for planes flown close to sea level, that 2.5 degrees of wing incidence is plenty. The prototype KR1 also exhibited a somewhat abrupt stall, with the left wing dropping quickly. He would add stall strips to the leading edge to soften the stall. He is still amazed at how well the prototypes flew, and mentioned that no changes were made to the original plans after the initial flights.

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Information for this design history comes from Jeannette Rand, Stu Robinson, and Kevin Kelly. Anyone with other insight into the KR design process is requested to email me, Mark Langford, at ml "at"