As "Ace Hunter," the would-be flamboyant, indomitable mercenary hero of Hal Needham's ludicrous combat spectacle "Megaforce," currently bombing out at area theaters, Barry Bostwick is obliged to cut the silliest martial capers since Captain America retired his tights and cape.

Although Bostwick is left in the most exposed position by the nonsensical war games invented for "Megaforce," it's obviously Needham who deserves the preeminent rap for fabricating a system of illusion so juvenile that the actors can scarcely avoid looking like chumps. And wimpy, cherry chumps at that. Described as "a phantom army of super-elite fighting men whose weapons are the most sophisticated known to modern science," the happy-go-lucky biker-warriors of "Megaforce" bear a closer resemblance to high school pep clubs than any other recognizable association, military or civilian.

Supposedly a quick-striking, hi-tech scourge of armored divisions, the Megaforce is enlisted by a threatened desert nation called Sardoun to retaliate against a warlike neighbor. Tanks under the command of Henry Silva, a good-humored villain, have violated the frontier, destroyed a power station and returned to safety across their border, since the peaceable Sardounians are loathe to violate frontiers themselves, even in response to thunderous acts of war. Instead, they send a British general, Edward Mulhare, and the potentate's daughter, Persis Khambatta, to enlist the clandestine assistance of the Megafops, a Mission Impossible Rapid Deployment Force subsidized in style by Free World governments and based at a subterranean command post in the Southwest. The plan of attack: lure Silva's tanks back across the border, where Mulhare's armor will be waiting, with a Megafops blitz on the aggressor's headquarters and ammo dump.

Ace and the boys would appear to stand their best chance of defeating adversaries by reducing them to fits of helpless battlefield mirth. The MF uniforms and accessories, which might have been designed by George Hamilton's Zorro the Gay Blade, are an especially funny provocation. It's difficult for Bostwick to impose a plausible semblance of battle-ready authority when he's expected to strike commanding poses in form-fitting gold or silver jumpsuits with his fluffy coiffure tied off by a baby-blue scarf.

The principal MF attack vehicle is an elaborately armored racing cycle, the Megafighter, which looks suicidally unstable. You'd expect the Megafighter to be knocked out of commission the moment its driver hit a rut or actually tried to use one of the rocket launchers mounted on its tinny front shield. The cycles are supposed to be augmented by small armored cars, called Megadestroyers, equipped with laser cannons, but they look slightly less roadworthy and formidable than soapbox racers. Needham himself may be glimpsed inside an electronically omniscient command vehicle, looking unjustifiably smug as he watches the flashing lights and TV monitors and pushes assorted buttons, supposedly directing the mission with pinpoint precision.

Obviously, one inconvenient bump or mechanical failure and that rickety AWACS would be instantly useless too. Needham may look like he's having a swell time at the controls of a kind of live-action video war game, but he's never in effective cinematic control. I needed a studio plot synopsis to clarify the antagonists and battle plans, which remain ridiculous even if you have access to this useful expository reference. Despite the victorious pretense, summed up in Ace's jaunty assurance that "The Good Guys always win--even in the '80s!" the evidence suggests that the Megaforce has blown a billion or two in exotic weaponry on an inconclusive suicide mission.

Needham, who made his reputation as a stunt man, has fallen into the strange habit of bungling or cheating action payoffs with reckless abandon. For example, none of the spectacular capabilities ascribed to the weaponry in "Megaforce" is ever reinforced by credible depiction.

The idea of the cycles and armored cars roaring out of a transport and gliding or parachuting smoothly to the ground looks utterly absurd. Ace's airborne Megafighter at the conclusion is too dependent on defective process photography to suggest a vehicle of the future.