Simple chip spewing question

Lately I've been picked up AK early in PartyPoker tournaments, in early position with the blinds at 10/15. I've raised to 50 and gotten 2 callers numerous times now. If the flop comes 8 J8 or 55 2, is it smart to bet at these type of flops with AK high? Or is it a natural check? I'm looking for something like this in Harrington on Hold'em for early tournament strategy as well as some people's +EV analysis. Sometimes I toss out a bet of 3/4s the pot and pick it up, other times I get raised or two callers.

Thanks.