A Rockville company plans to use some microwave magic to detect and combat icing on helicopter rotor blades and airplane wings.

Ideal Research Inc. has developed a Microwave Ice Accretion Measurement Instrument, or MIAMI. This warning device utilizes a surface wave guide, or transducer, mounted flush on the leading edge of the wing or rotor blade to generate microwave beams whose characteristics change if ice forms on the guide.

A microprocessor monitors not only the thickness of the ice but the rate of accretion, and can recognize the difference between ice and other substances that could adhere to the wings, such as oil, dirt or insects. A cockpit light or warning tone alerts the pilot when ice is forming on the wings or rotor blades.

Company President and inventor Bert Magenheim says that the MIAMI has advantages over existing ice-detection instruments that utilize high-frequency sound waves or infrared radiation. He said that these instruments cannot be put on wings or rotor blades because they protrude and would disturb the aerodynamic profile, so pilots have to infer from the amount of ice measured elsewhere how much ice is on the wings or rotors. He added that those instruments can measure only small buildups before they must be deiced.

Magenheim said he created the MIAMI because he knew that the Army needed all-weather helicopters, he knew how microwave ovens work and he knew that ice is a good medium for the transmission of wave types of energy.

He believes that his MIAMI also could be used on the ground, for example, by electric power companies to monitor the amount of ice on transmission lines, which now is done by visual inspection.

"We've got all the hard scientific data that we need" and are ready to decide which components to manufacture and which suppliers to go to for the others, Magenheim said. Production is expected to begin in July 1984.

"If I had my desires, I'd make it the manufacturing plant in this area," Magenheim said. "The beauty of it is that it's a relatively simple device." He said that the company could produce up to several thousand a year.

Magenheim has worked in the microwave field since the 1950s, and last was employed by System Development Corp., a communications consulting and software firm. He formed Ideal Research Associates in 1977 to work on icing problems after being unable to get support for it when he was with SDC.

Magenheim won funding to develop and test the MIAMI from the National Aeronautics and Space Administration's Lewis Research Center in Cleveland, which a spokesman said has one of the bigger and better icing wind tunnels in the country.

NASA not only will fund unsolicited proposals it considers feasible and of particular interest to its mission, but it also will try to spin off to the private sector the technology it has developed, according to Sandy Felger, a technology utilization specialist at the Lewis Research Center.

The agency was directed by Congress to assist in engineering research, development and demonstration programs in aeronautical and space science and technology, explained Peggy Evanich, an aerospace engineer at the center.

Besides the microwave warning device, Magenheim also has won a patent on a deicer that would use microwaves to raise the temperature of the ice just enough to break the adhesive bond between the ice and the aircraft wings. The deicer has not been built, and Magenheim said that "the only people who are going to fund it, I suspect, are the military."

Magenheim estimates that one or two wave guides would suffice for small aircraft, while up to five might be used for large ones. Ralph M. Sollod, Ideal's vice president for organization and marketing, said that the MIAMI probably will cost between $1,000 and $2,000 once production is geared up. Sollod noted that a microprocessor can handle several transducers, so the price wouldn't double were an aircraft equipped with a transducer on each wing.

"We feel the greatest market is general aviation aircraft small private planes , which fly . . . between 2,000 and 10,000 feet, where ice is really a problem," he explained, adding that the secondary market would be helicopters, where ice is a significantly greater problem because its mass on the rotor blades can affect aerodynamic stability and rotor structure.

Jet airliners would not be a prime market because they climb and descend quickly through altitudes where ice tends to form, Sollod added, an assessment supported by government and industry spokesmen.