Published: June 27, 1982

Ya-hoo! Those fellas wielding the high-tech weapons in Hal Needham's ''Megaforce'' may look like space patrollers, but they're really good old boys at heart.

So what if an opening title defines Megaforce as ''a powerful army of super elite fighting men whose weapons are the most powerful science can devise?'' On a tour of the cavernous Megaforce headquarters, a guide remarks on the folksier aspects of the installation: ''Shoot, we used $40,000 worth of mops and brooms last year just tryin' to keep this place clean!'' In the control room, there is a computer that, when asked to analyze the background of one visitor, tells him ''Your daddy's rich and your mama's goodlookin'.'' Of one scientist, it is said ''That man's got more degrees than a red-hot thermometer.''

Mr. Needham, the former stuntman who directed Burt Reynolds in ''Hooper,'' both ''Smokey and the Bandit'' films and ''The Cannonball Run,'' has tried in ''Megaforce'' to combine down-home joviality with stunts, special effects, funny-looking futuristic jumpsuits and a great deal of hardware. The combination is original -just as a peanut butter and olive loaf sandwich might be - but it isn't any good. Furthermore, Mr. Needham's secret weapon is Mr. Reynolds, and Mr. Reynolds isn't here. Without his overriding friendliness and humor on hand, there is too much opportunity to notice the weak spots in Mr. Needham's direction. In the case of ''Megaforce,'' these include silly dialogue, poor matching shots, oafish staging, and one scene filmed between two silhouettes against a magenta background.

Barry Bostwick has the role that might have suited a younger Mr. Reynolds, if indeed it could have suited anyone. He plays Ace Hunter, the head of Megaforce, a man wearing a skin-tight jumpsuit and a rakish smile. Mr. Bostwick, with his hair dyed blond, attempts a swashbuckling manner that is lost on Persis Khambatta, his ostensibly romantic co-star. Here and in ''Star Trek: The Motion Picture,'' Miss Khambatta has had to wear some of the most ill-fitting outfits ever designed for the screen. Unlike Mr. Bostwick, who at least tries to remain animated, Miss Khambatta has a wooden presence here. She even has trouble with a line like ''I wanted it to be different,'' which is about the best line the screenplay allows her. Also in the cast is Michael Beck, the stony, silent hero of ''The Warriors,'' who plays Mr. Bostwick's chatty and good-humored Southern sidekick. Neither he nor Mr. Bostwick has yet been given as interesting a film role as he probably deserves.

''Megaforce,'' which opened Friday at the National and other theaters, has lots of stunts, including some skydiving by stunt people who don't much resemble the actors, and a routine that shows two dozen motorcycles trailing multicolored smoke. The movie was filmed in the desert through red-brown filters, and there seem to be big clouds of dust everywhere. At best, it will make you thirsty.

''Megaforce'' is rated PG (''Parental Guidance Suggested''). Its characters cuss a little.