Winnebago Industries, Inc., one of the nation's largest motor home manufacturers, today introduced a propane power system meant to protect recreational vehicle owners-and the RV industry-from gasoline shortages.

The $599 option allows motor homes to burn either gasoline or propane, which Winnebago officials said now costs an average of 51 cents a gallon and is available at 2500 outlets across the nation. A dashboard control switches fuel.

Most motor homes average from six to 14 miles per gallon and get about one mile per gallon less with propane, said Fred Emmert, Winnebago's vice president for marketing. But the lower cost, higher performance and assured availability of propane-which the company said is in oversupply-make it an attractive alternative to gasoline, Emmert siad.

"We're trying to answer the RV ownerhs worst fear-that he'll get to the beach or the mountains or the desert and can't get home again because he can't get gas," he said.

The innovation is also aimed at the RV industry's worst fear-that gasoline shortages and closed filling stations will destroy the $6 billion a year industry. With sales of $230 million a year Winnebago is one of the biggest motor home manufacturers, turning out 15,000 units every year.

But sales have slumped this spring and with an inventory of nearly 2000 unsold motor homes, Winnebago is preparing to shut down its plants here and in Forest City, lowa for six weeks starting June 1, and lay off all production workers for that period.

The company has equipped about 50 of its Winnebago and Itasca motor homes with what it called the "dual/fuel system" and plans to have at least one for each of its 528 dealers by the end of June. The company has committed orders for nearly 5000 propane conversion kits manufactured by a Los Angeles firm, Impco Corp.

The system can be retrofitted to existing motor homes and will probably become standard equipment in the future. Winnebago chairman John K. Hanson predicted it will be followed by a gasless RV using either propane or hydrogen.

Most motor homes already have propane-fueled stoves and refrigerators which will run off the same tank as the engine. Two sizes of tank-good for about 100 or 200 miles-will be offered by Winnebago.

Also known as Liquified Petroleum Gas (LPG) propane is widely used for cooking and heating and powers many vehicles especially forklift trucks used in warehouses where its low pollution advantage is needed.

Emmert said motor home sales are not as bad now as they were during the 1973-1974 gas crisis when Winnebago built up an inventory of more than 4000 unsold units.

But he said dealers are offering large discounts from the $10,000-plus list price on motor homes and he conceded "There will be some attrition of dealers due to the sales slump."

The Recreational Vehicle Industry in general has been hit hard during the recent gas crunch. In the first quarter of 1979, unit sales fell 13.9 percent, to 105,000 from first quarter 1978 sales of 122,000, according to the Recreational Vehicle Industry Association.

March sales were off 28 percent from the same time last year, the association said, dropping from 54,000 to 40,000.

Winnebago has cutback motor home production by 14 percent and has already laid off 270 employes, about 8.7 percent of its workforce.

The industry still has not recovered to the sales level of its best year, 1972, when 564,200 units were sold. The 1973-74 oil crisis caused sharp drops in sales-including a 44.1 percent drop in 1974.