Groen Bros. Aviation Inc., designers and manufacturers of the Hawk Autogyro, a rotorcraft that is a cross between a helicopter and an airplane, is planning to move its Salt Lake headquarters and manufacturing plant to Tooele next year.

Jay Groen, president of GBA, said the city of Tooele has deeded his company 20 acres in the Tooele Industrial Park, "which has an airport and large runway that will greatly accommodate our business expansion plans."Groen and his brother, David Groen, secretary and treasurer of GBA, said they plan to begin building a 50,000-square-foot manufacturing facility and a two-story office building at the Tooele Industrial Park in the summer of 1991.

"We hope to move from our facilities at 1784 W. 500 South in Salt Lake City to Tooele by the end of next year," Jay Groen said.

He said his company has already successfully test flown a prototype of the Hawk Autogyro and is nearing completion of a production prototype.

The Hawk Autogyro's projected flight specifications show an empty weight of 750 pounds, a gross weight of 1,500 pounds, a top speed of 160 miles per hour and a slow speed of 15 miles per hour.

The new aircraft, which is being certified by the Federal Aviation Agency, flies on the same principle as the autogyro of the 1930s but has modern aerospace design and performance, Groen said.

"The market for our Hawk Autogyro is significant and includes law enforcement, border patrol, military surveillance, land management, crop spraying and other domestic and international civil, military, commercial and general uses.

"The craft is safe, economical, fast, maneuverable and capable of vertical takeoff and landing," he said.

David Groen said GBA, a publicly traded over-the-counter stock, expects to make a secondary issuance of stock soon to help the firm pay for expected production costs.

Earlier this year, Gov. Norm Bangerter visited the Groens' facility to congratulate the two brothers for their enterprise and ingenuity. The brothers are both veterans of the Vietnam War and have been business partners over the past 15 years.

A year ago, the Utah Technology Finance Corp., a quasi-governmental organization that lends money to promising Utah companies, lent the Groens $50,000 to help them design and develop a rotor-blade system that lifts the Hawk Autogyro.

Since then, state officials and representatives of law enforcement agencies and the military have toured the plant to find out more about the new aircraft.

David Groen, a helicopter pilot in Vietnam, said the Hawk Autogyro is much easier to fly than a helicopter and much less costly to purchase, operate and maintain.

The two brothers are the authors of the best-selling novel, "Huey," a story about a helicopter assault pilot in Vietnam, based on the experiences of David Groen, who piloted a combat helicopter in the war, and his brother Jay, who served as an Air Force intelligence linguist during the Vietnam War.