ahem...your maths is abit off
simple example:
500$ risk , 2:1 Risk reward. 50% Hit ratio.
For each 500$ risked you gain 1000$.
20 trades , 10 Losers and 10 winners.
I'll leave the rest of the math to you.
Using say 7% , 3 losers in a row and you have 20% drawdown.
Some mistakes more...