Well, when I was in the Aircraft Owning business, I would take what ever the cost of fuel that I was buying per hour and multiply by a factor of 5 for airplanes and 10 for helicopters. So if you take franks fuel burn of 14 gal an hour @ $2.00 a gallon, its more like $3+ you get 28 dollars an hour, times 10 and you get a good ball park DOC of 280 USD an hour. its a quick way to get an Idea of what the per hour DOC's is going to be. of course you would then fine tune it a little. Frank uses the 500 hours a year to work his numbers. To not consider the other costs, such as finance, Insurance and hangar is not giving the whole story. An R-44 or any helicopter is going to be an expensive toy with out it being used to generate some sort of revenue stream. The Idea of a helicopter as a rec vehicle is at best a dubious one. You need a very large income stream to do so.