Night Launch - How many Lumens do you need?

So we want to fly in the October Skies night launch and are curious what it takes to have enough light onboard to see the whole flight and then find a rocket in the dark. Is there a minimum amount of Lumens that make it visible for a flight that goes to 2,000 feet altitude and then drifts a half mile away?


We got a 50 Lumen camper's headlamp that fit in the unpainted nosecone of an Estes Leviathan. When we lit it up in the garage, it illuminated everything brightly within five feet. Is that enough?

That is probably more than my hopeful night flight, though my lights are external, and I am looking at 1600 feet. Is a Leviathan going that high with extra weight? You could also use a smaller motor.

We have always said for out night launches
"Models between 1 lb and 3.3 lbs must have a high-intensity light source such as a strobe or high-output LEDs (minimum 2000 mcd visible at 2000 feet)."

A quick online converter says that 50 lumen at a wide angle (like diffused through a nosecone) is about 27,000 mcd.

I think you'll be fine.

kj

We'll probably start out with an F or small G motor which will keep it low. If all works well, we may throw in a G75 Metalstorm for a Roman Candle effect. If that doesn't send it too high, we'll go with a G145 Pink.

Didn't realize there might be club rules on minimum visibility but it makes sense.

it depends on what you're trying to accomplish. If you just want to make sure that you recover your rocket then 50 lumens is probably fine. If you want to put on a light show then you should consider using some high intensity LEDs, maybe find some LED light strips that do sequential flashing or something of that nature.

you need a string of 300 5630 LEDs wrapped into a 20 inch space !

[video]https://youtu.be/Za9r5ktAXN0[/video]

Kenny

KenRico said:

you need a string of 300 5630 LEDs wrapped into a 20 inch space !

[video]https://youtu.be/Za9r5ktAXN0[/video]

Kenny

Click to expand...

Exactly. A setup like this will rule the night.

I hope you get to run that pink motor at night, would love to see it!

My experience has been, it depend on who is running the night launch and how fast they want to get out of there.

If it is truly a night launch and after dusk, not just sunset, then you don't need as much since it is dark and a little light can be seen from a long ways in a dark field well away from city lights. Flashing light seem to be more easily seen also. If the launch is during dusk and it's not truly dark, then you will need more light to see it against the not quite dark field. It take a surprising little amount of remaining light from a dusk launch to obscure the light in your rocket.