Therefore, V A is equal to J into n D. I can calculate my wake. Is that correct? Good. One assumption only I have made that, when I enter this chart, I assumed that the propeller open at a characteristics and propeller behind characteristics are same. That immediately you will note that it is not same, because I have got K T. I have entered the chart with K T. What if I enter the chart with K Q? I should have actually got this value this, but I will find that my K Q is not here, but somewhere here, which means then I getting a different J and different wake.