help with led

any one help me please...

I fly rc helicopters and am very interested in night flying, to do this you have to light the heli in a fashion that dictates orientation. There are several companies that produce pre assembled rotor blades and plug and play led light strips..I plan to use the light strips to light the tail boom and canopy but i want to make my own blades useing leds. This is the digi-key part number for the led kit i plan to buy http://http://www.digikey.com/product-detail/en/511-8007-KIT/511-8007-KIT-ND/1777673      i plan to use 4 or 5 leds on each blade 2 of the same color on one side of the blade and 2 or 3 different colors on the other. I am going to use a single cell lipo battery for each blade. The battery tops off at 4.2v dc @ 300mah the nominal voltage is 3.7v dc my question is what ohm resistors should i use for each led? or can some one give me a formula to figure it out for my self... thanks for any help