OTTAWA—The federal government has officially launched a competition for the purchase of armed drones after nearly two decades of delays and discussion around whether Canada should buy the controversial weapons. A formal request for proposals was released Friday to the two companies shortlisted to bid on the $5-billion contract, which could see the Canadian Armed Forces launch a fleet of unmanned aerial vehicles in the next few years. A formal contract is not expected for another year or two, while the first drone isn’t scheduled for delivery until at least 2025, with the last to arrive in the early 2030s. The request does not say how many vehicles the government plans to buy, and instead leaves it up to the two companies to say how their bids will satisfy the military’s needs while benefiting the Canadian economy. It does reveal the aircraft will be based at 14 Wing Greenwood in …