R.N.A.S. Title

[8Hussar]

Picked this up with a lot of Canadian flashes but all that I can find that refers to a RNAS flash on the forum is a curved example that is from WWI. My question is, what period is this from? Before anyone is kind enough to let me know the period of use of this badge I will warn you that I do not collect these so it will end up on ebay if someone here doesn't pm me to entice me to sell it to them direct. Thanks for your help with this.
Gary