In a note to investors on Wednesday, RBC Capital Markets General Manager Mike Abramsky suggested that sales of RIM’s new BlackBerry PlayBook tablet may be exceeding the company’s initial expectations. According to Abramsky, RIM may have increased the number of tablets on order from its manufacturing partners by as much as 100% to between 1.2 and 1.5 million units for the second quarter of 2011. The note cites strong sales estimates as one possible cause, and also states that the launch of 4G-enabled versions of the PlayBook may have been pushed up to June — another possible cause for the ramp up. Despite the possible increase in orders, RBC maintains its earlier sales projections of 500,000 PlayBook tablets in RIM’s May quarter and 4 million units total in 2011.