62887
However , NACA studies indicated that the V-tail surfaces must be larger than simple projection into the vertical and horizontal planes would suggest , such that total wetted area is roughly constant ; reduction of intersection surfaces from three to two does , however , produce a net reduction in drag through elimination of some interference drag .
 NACA
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 NACA