Can I age and flavour vodka in an oak whiskey barrel, and would it taste like whiskey in a few years. Not a big barrel, just 15L new barrel.?

If the vodka were distilled from grains and the inside of the barrel were charred, the result would not only taste like whiskey, it would BE whiskey.

If that's so, why does scotch made with peat-smoked barley taste so good? I'm not sure what you'd get with vodka in a barrel, but it wouldn't be whiskey and it wouldn't be vodka. Starting out with less than 50% alcohol the product would probably be pretty low strength.

Bourbon barrels are, by law, new and unused. Virtually all distillers order barrels that are charred - set on fire inside so they are lined with charcoal. Scotch and other distillers buy the used bourbon barrels for aging their whiskey. 

I once bought some moonshine that was aged with a couple of charred sticks in it. It really mellowed out the booze until it was almost drinkable.So.

You're not going to get bourbon or Tennessee whiskey by aging vodka. Distillers put newly distilled alcohol in their aging barrels, that is about 90% alcohol. They also have special mash blends that add flavoring to the distilled spirits (rye whiskey is a good example). So, given this information I doubt you can come up with a great drink aging vodka in your own barrells, but I'd like to be there if you enter it in the science fair.

A NEW barrel will not have much flavoring to impart in an alcohol. 

that's a lot of cost and effort for something that probably won't work.

what does work is the whisky aging stick for about £15.