The R's were relegated from the Premier League two years ago, with several players given lucrative long-term deals by the club subsequently unable to be sold once in the Championship.
"The club have spent an astronomical amount of money but we didn't have great success in return for that incredible outlay. That was the bomb," Holloway told the QPR site.
"I knew that before I came here. This isn't new, this isn't about now. That bomb went off a couple of years ago. I am here to tidy things up, and help my owners get value for money from everyone we've got, and whoever we might get.
"What we want to do is make this club sustainable. So I need the fans, more than anybody, to be patient, to trust me and to see what we are all trying to do here."
QPR finished 18th in the second tier last season, just two points clear of the bottom three.