LED setup on a high power rocket

I'm building a high power rocket for night launches. I want to illuminate the rear with many led's in a ring. This thing will reach 1-2 mile altitudes so the led setup must be extremely bright to avoid losing sight of the thing. What led's should I purchase which have the highest visable intensity, and how could I calculate the battery size needed to power them all for about 20-30 mins? I'd like to use maybe 20-30 leds.

Single-LED lights advertise one-mile visibility, so unless you specifically want 20-30 LED's worth of flash, you might not need to use so many -- especially if you used a circuit that flashed them in a pattern.

If you aren't particular about color, red-orange LED's will give you more for your battery budget as well.

For your application, I expect that you should be able to get away with a small battery pack made up of LR144's or other coin/button type cells. For 20-30 minutes of use, I doubt you'll need more unless you do use 20-30 LED's.

Do you know what the rocket's "cargo capacity" is? How important are balance/weight distribution issues?

Would red-orange led's be as visable to the eye as a green or white led at night?

I want to use a ring of light on the bottom, and maybe some going up the sides in case the bottoms not facing straight down while under the chute.

Although any extra weight won't benefit, it could haul an extra pound or more if need be, so I don't really focus on attaining the lowest weight possible at this point.

green would be the best visable at night. red-orange won't be too good at night at distance.

I know this is an LED forum, but I think you should consider a xenon flash tube. There's a reason that this is the traditional 'light marker' solution. Using the D cell powered module from the 'life vest flasher' (about $15) driven from an AA cell should give very bright flashes for over an hour.

Doug Owen

Welcome to CPF!

As Doug Owen said! I've built several, but the most powerful rockets used were Estes D's. Makes an interesting game of "fetch" at night in the desert, but watch for rattlers. /ubbthreads/images/graemlins/grin.gif The cheap strobes are visable for over 2 miles, and with a Lith AA runtime is several hours. Rep rate just slows as the cell is depleated.

Low forward voltage Luxeon emitters, direct-driven on a 123 cell might work pretty well without requiring much of a heatsink weight penalty. As to viable visability at a mile and a half? /ubbthreads/images/graemlins/icon3.gif

what about flashing? that would attract more attention (be obnoxious) also if your seeking out something in a partly light up area, flashing can discern itself from the ambient.
like if its just over that hill and the light over there keeps CHANGING instead of looking like moon glow.

Alright, I'll still use the continuous led setup on the bottom, however I will use a strobe in a clear payload compartment. So what kind of strobe should I be looking for? I want the brightest possible, it can easily use the regular D cells for power, as this rocket lifts with 200+lbs of thrust. Thanks for the advice guys.

http://www.imsplus.com/ims26.html
"EMERGENCY STROBE LIGHT"
these things are cheap take a Dcell , and would be cheaper than a "kit" , so much cheaper, if you wanted the parts, you could tear them out of it.