The pilot reported that as the aircraft became airborne, he noticed a loss of engine power and believed the aircraft may have touched the ground after the landing gear was selected up. He was subsequently unable to obtain a gear down and locked indication, although the gear appeared to ground observers to be fully extended. During the landing roll the right main gear collapsed. The right gear did not fully retract or extend because of damage sustained by the retraction mechanism, probably as a result of ground contact after the down lock had been released. The engine power loss was probably caused by an intermittent breakdown of one magneto, and/or a partial blockage of fuel injector nozzles by particles of corrosion from a fitting on the manifold valve.
