Streamer Recovery

[Daniel Runyon]

I'm starting to want to squeeze a little more altitude out of my relatively small field (roughly 1500 x 600 feet) so I'm exploring streamers.

In the Handbook, I've seen that a fellow from MIT has determined that the optimum streamer ratio in relation to itself is 10 to 1... if the streamer is 1 inch wide it should be 10 inches long.

The Handbook also makes mention of there being some discoveries of optimum streamer size based on the rocket itself, but doesn't go into any detail so I was hoping you folks could fill in some blanks a little. Are there any rules of thumb that you know of?

Also, what are the pros / cons of different materials? The only experience I've had is with the orange "marker" plastic ones that come in the crappy little disposable plastic Estes Super Shot rockets from Wal Mart! I already have some mylar sheets, but I'd be willing to seek out the good stuff if you have any recommendatons!

[CPMcGraw]

I'm starting to want to squeeze a little more altitude out of my relatively small field (roughly 1500 x 600 feet) so I'm exploring streamers.

In the Handbook, I've seen that a fellow from MIT has determined that the optimum streamer ratio in relation to itself is 10 to 1... if the streamer is 1 inch wide it should be 10 inches long.

The Handbook also makes mention of there being some discoveries of optimum streamer size based on the rocket itself, but doesn't go into any detail so I was hoping you folks could fill in some blanks a little. Are there any rules of thumb that you know of?

Also, what are the pros / cons of different materials? The only experience I've had is with the orange "marker" plastic ones that come in the crappy little disposable plastic Estes Super Shot rockets from Wal Mart! I already have some mylar sheets, but I'd be willing to seek out the good stuff if you have any recommendatons!

IIRC, the Handbook uses the 10:1 ratio as the "optimum" measurement; so does RockSim...

As for the materials, you can pick up 1.75" wide paper streamer material, 81' long, in the party supplies section at Wal Mart for $.50, so if you only get a couple of flights out of one before it gets trashed, you've only got a few pennies tied up. Really easy to justify having a few on hand. For thin 2" wide vinyl streamers, go to Lowes / Home Depot, and look near the tools section. It's sold as demarcation tape (like police tape), and a 300' roll is only a few dollars.

[Daniel Runyon]

IIRC, the Handbook uses the 10:1 ratio as the "optimum" measurement; so does RockSim...

Yessir, but how would one determine the optimum width to begin with? In other words, when would one use a streamer that is 1/2 wide and 5 inches long, or 2 inches wide and 20 inches long. He only gave the optimum ratio for the streamer itself, but no information relatively to the size / weight of the rocket itself.

Gracias!

[CPMcGraw]

Yessir, but how would one determine the optimum width to begin with? In other words, when would one use a streamer that is 1/2 wide and 5 inches long, or 2 inches wide and 20 inches long. He only gave the optimum ratio for the streamer itself, but no information relatively to the size / weight of the rocket itself.

Gracias!

That's the beauty of it -- as long as the length is 10x the width, the streamer works. Granted, it may be difficult to stuff a 2" wide streamer into a BT-5 or ST-5 tube; it's plenty difficult stuffing anything into one of those! Best suggestion is to plug different size streamers into a RockSim simulation and see which ones bring the descent velocity into your range of acceptable impact. Also, check the 2D flight playback mode and see what RockSim shows the fall to look like. Select a size that reduces the distance from the pad to something inside the range of your field, and still reduces the drop speed comfortably. Keep in mind, the model is going to hit the ground faster than if it were on a parachute...

[Daniel Runyon]

Alright, much appreciated... I hadn't thought of using RockSim for that. Any ideas of what I should be looking for in terms of ideal descent rates? They will be landing in grass, but I'd like to keep damage to a minimum, if any... obviously!

[CPMcGraw]

Alright, much appreciated... I hadn't thought of using RockSim for that. Any ideas of what I should be looking for in terms of ideal descent rates? They will be landing in grass, but I'd like to keep damage to a minimum, if any... obviously!

Well, with a parachute, you might look for about 11-13 FPS as the "slow" descent rate; the slower the rate, the softer the contact, but at a greater risk of drift. I'd think less than 20 FPS for any model, whether on a streamer or a parachute.

Most light models will tend to fall horizontally, so that will also reduce the descent rate. Heavier ones might fall vertically, so they would need the larger streamers. Consider the possibility of multiple streamers to increase the drag and reduce the vertical velocity. Don't limit yourself to just one, if the model needs more drag. Just remember the ratio of 10:1 for each streamer. Mix sizes to "tweak" the descent rate.

[Daniel Runyon]

Thank you VERY much!