Hallmarks of Homebuilding

Ken Rand's Composite Airplane, The KR-1

Ken Rand in his KR-1 at Oshkosh.

Among the most talked about airplanes at the 1972 Oshkosh EAA Convention and Fly-In was the Rand Robinson KR-1 created by Ken Rand of EAA Chapter 92 in Huntington Beach, California. Not so much the airplane, which was so small that some EAAers figured it had to be either a large RC model or some over-indulgent father's taxiing toy for his child.

What made the airplane special-and what now accords it "Hallmark" status-is how it was put together and what it was made out of. Its plywood and spruce box fuselage was just like most wooden airplanes, but the engine cowl, fuel tank, fuselage turtle deck, vertical and horizontal tail surfaces, and outer wing panels were completely or largely constructed of a new composite construction method.

Slabs of polystyrene foam were glued in place, trimmed and sanded to the desired profile, on which a layer of Dynel cloth was then epoxied to form a tough and (when sanded) smooth exterior. The foam had little to do with the strength of the finished product, but rather was a filler and, more importantly, a built-in mold or form on which the layer of Dynel and epoxy was added, forming an incredibly light and strong outer shell. This construction method made compound curves and sleek shapes possible on structural members of the aircraft.

The KR-1 ignited use of composite materials in homebuilding.

Rand's little airplane had a 17-feet, 2-inch wingspan and measured but 12 and a half feet nose to tail. It weighed in at a mere 310 pounds, and most of that was engine and prop.

But this airplane represents Rand's innovative process that was a totally new way to build a structure. This aircraft paved the way for the many composite aircraft that were to follow. Today hundreds of aircraft, including some very high-performance designs, use composites as primary structures.

In a feature story appearing in the January 1973 edition of Sport Aviation, former editor Jack Cox wrote about the KR-1:
"The KR-1 is one of the most highly innovative homebuilts to ever make an appearance at an EAA fly-in. Many look at the simple, light and inexpensive polystyrene foam/Dynel/epoxy sandwich construction as the 'breakthrough' that has been needed in the homebuilt world. With it there is no longer any need for our birds to be boxy; the compound curve is no longer a bug-g-boo; and glass-like finishes previously seen only on expensive European sailplanes is within the reach of every homebuilder."

Rand's prototype KR-1 (N-1436) that he brought to Oshkosh in 1972 is a part of the EAA AirVenture Museum collection. Oshkosh visitors can see it on display at Pioneer Airport during the flying season.

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