SO I need to use some 1W and 3W leds for the brightnes, but my application will not allow the start heat sink. I have come across a few articles talking about using PWM to drive LEDs Does pulsing an LED at higher current yield greater apparent brightness?
What got me in the link above is
as you reduce your duty cycle you can increase your current because there will be less time for heating affects to kick in. I have done this with a very very short duty cycle using a pulsed laser power supply at 2kV on a normal 1.9V diode. This was pulsing so often that they eye cannot tell. the brightness of the diode increased significantly. My professor and I built a power supply that had a short duty cycle and only overvoltaged the diode to a little over an amp of current and successfully made a normal diode look brighter then a 1W LED when it was only a cheap LED. – Kortuk Jul 28 '11 at 16:09 Blockquote
What I'm needing to achieve is an LED that can be seen in day. I'm putting them on a RC Airplane.