Thoughts on streamers for mid-power?

What is the consensus regarding using a streamer for recovery for mid-sized, mid-powered rockets? I've only ever used them on lightweight, 13 or 18mm motor rockets that were no more than a couple ounces. Are larger streamers a viable alternative for something that's, say, 10 - 15 ounces (without motor), flying 29mm motors?

It depends. But as the rocket gets toward a pound it is less of a good recovery solution.

Smaller rockets can use streamers since a) they have a small mass, and b) high-drag to mass ratio with the streamer. A 6" diameter rocket will have a higher drag ratio as opposed to a 2" diameter rocket, with both having the same mass. As mass increases, the mass per volume needs to go down to use a streamer. But there are practical limits, which is why you start to see streamers at a certain mass break.

Greg

I'm in the process of building a US Rockets All Weather which comes with a streamer.
The specs say it's only 7.5 ounces, though, so not quite what you are looking for.
You can see on the link page that a chute is used on a higher powered application but it looks like a rather hard landing surface.

My Leviathan was flown with a cable-cutter several times in which the chute never opened. So with the burrito acting as a drogue, the 2.2-pound Leviathan fell to the ground. It was unscathed every time.

I would think you would get even more drag with a long streamer than you would with an unopened parachute, but I don't know. Something to factor in, anyway.

I'll tend to use a giant streamer and a small parachute below that. The combined drag of the two slows the rocket to a safe landing speed, but the streamer gives me good visibility.

Bat-mite, I had something similar happen on my first L1 cert flight, except there the swivel broke and the parachute came off. My "drogue" was the nomex chute protector blanket. My 2.4 pound Der V-3 upscale fell 1500 feet with minor damage, but it was built a lot more rugged than this will likely be.

Perhaps some background is in order. The rocket in question is on the light end of mid power, and probably work just fine as a 24mm mount bird with some modification. What I'm working on is a design for a Estes 0882 Ninja, upscaled to BT-70 tubing. That makes it just over 3X scale, and puts it just short of 32" long. I do not recall offhand what Rocksim says the mass will be. But I can't imagine it being more than 10 oz or so, since it uses thin-wall tubing, a balsa cone and 1/8" basswood for the fins. It does, however, have a 29 mm mount, so there is ample opportunity to overpower it. So here are the two reasons I'm looking at a streamer:

1. the original Ninja used a streamer, so using a large streamer would be more scale-appropriate. This is a minor thing and would not hold me to doing so if it looked like a bad idea.
2. with a G80 SU motor, it'll handily apex 3000'. The design is single deploy (trying to stay scale structurally), so the drift on a 24" parachute is probably (a lot) farther than I'd like.

I could, of course, restrict myself to using F23-7FJ or E30-7 motors, which would take it into the 1000-1500' ballpark and thus cut the drift down. But I hate building in restrictions like that. And I have a sneaking hankering to put a V-max motor in it at some point... I suppose I could modify the design to allow for DD conversion, but I have zero experience with setting up a dual deploy rocket and none of the hardware required. To this point, I've avoided the complexity of DD for a number of reasons, and I like simple. And the design is, as it stands, simple - 3FNC, black paint, basic decals. And hopefully something bright orange that comes out of the end to make it easy to see...

I have a 1 pound Loc Lil' Nuke that I have come down on a streamer from 3500'. Streamer is 10 inches by 10 feet. Comes down fast, but not too hard, even in the hard desert we have out here.

Do you have an idea what the rate of descent is for that?

I've used large streamers as a drogue for my dual-deploy Ventris, mainly to make it somewhat more visible at 3000' rather than to retard its descent. I think it wouldn't be a viable main deployment option for anything over maybe 8 oz., streamers just don't generate enough drag to slow down anything relatively heavy.

I use streamers with MPRs when I fly at the sod farm. It's fine if it lands in the nice soft grass, not so nice if it lands on the rock hard dirt.

EXPjawa said:

Do you have an idea what the rate of descent is for that?

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I did not get any data on it during its last flight, but I will try next time.

According to Rocksim, the rocket will be approximately 8.5 oz, assuming I don't overdo the paint. With a 6x60" streamer, it gives a 22.8 fps descent rate, provided the streamer is folded/creased. The drop is 39.5 fps if not. Side note: the sim seems to crash if it has a streamer rather than a chute. Is this normal for Rocksim? Seems silly if it is. OTOH, I get a 23.1 fps descent using an 18" chute, though I like the visability of a 5 foot long streamer better. Also, FWIW, I'd mostly be landing on some sort of crop, either wheat or carrots this season. Corn if it goes too far.

I have a 4", 2 lbs rocket built to recover on a 30" wide x 42' (yes foot) long streamer. It was an experiment into high power streamer duration.
It would deploy but dropped like a stone breaking fins every time.

M

EXPjawa said:

What is the consensus regarding using a streamer for recovery for mid-sized, mid-powered rockets? I've only ever used them on lightweight, 13 or 18mm motor rockets that were no more than a couple ounces. Are larger streamers a viable alternative for something that's, say, 10 - 15 ounces (without motor), flying 29mm motors?

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I've flown small rockets with streamers. I think the biggest was a Fat Boy built with balsa and yellow glue (stock except for a better grade of wood and a 29mm mount). This design needed a bit of nose weight. One thing I noticed on recovery was that the fins seem to have a lot to do with recovery velocity. The body was coming down almost horizontal, almost as if the streamer was carrying the load of the nosecone alone. The streamer was a 6' piece of 3" wide corrugated aluminized mylar. I only launched this configuration over grass soccer fields, I used a parachute over concrete/asphalt.

MClark said:

I have a 4", 2 lbs rocket built to recover on a 30" wide x 42' (yes foot) long streamer. It was an experiment into high power streamer duration.

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MClark said:

It would deploy but dropped like a stone breaking fins every time.

M

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https://www.rocketreviews.com/streamer-calculator.html

According to this calculator your 2 pound rocket on a 30 inch wide streamer should have only needed to be about 40 inches long.

Sounds like either the math is AFU or there's a rather low upper limit to streamer utility as far as lowering descent speed goes.

Well, I gave it a shot. The rocket was 8.3 oz without motor; I attached a 6"x60" streamer. The rocket dropped pretty fast; I think the body had as much drag as the streamer, because it dropped nose cone first, with the body and streamer next to each other. It landed near the pad, however, with quite a thud. No damage though. I think I'll go to a parachute, and maybe pack a streamer for visibility.

Several years ago the TARC rules called for recovery without a parachute. I only saw the ones that made the finals, but they all used streamers to bring their rockets down safely and without breaking the raw egg payload.

I'm sure streamers can be used on MPR rockets for safe recoveries, especially if they don't carry eggs.

EXPjawa said:

What is the consensus regarding using a streamer for recovery for mid-sized, mid-powered rockets? I've only ever used them on lightweight, 13 or 18mm motor rockets that were no more than a couple ounces. Are larger streamers a viable alternative for something that's, say, 10 - 15 ounces (without motor), flying 29mm motors?

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Are you looking to fly streamer for a particular reason? I'm wondering if your flights are a candidate for Chute Release, or if there's a particular reason you're interested in streamer recovery.

I used to fly my older Onyx on a streamer from time to time just to see if it could be done. It could. I didn't even lose a surface mounted fin either. I think from here on out though my use of streamers will be on smaller altitude based mid power.

John Beans said:

Are you looking to fly streamer for a particular reason? I'm wondering if your flights are a candidate for Chute Release, or if there's a particular reason you're interested in streamer recovery.

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John, the biggest reason was that the model in question was an upscale of a much smaller rocket that used a streamer. My thinking was that if I could keep in light, I could upscale the streamer as well. However, reality has set in, and it would seem better suited to fly it on an 18" parachute. The streamer probably would work better if I could fold the nylon and get it to stay creased, but as it is, the streamer just didn't offer enough drag to be to be practical. That said, it is an 8 oz rocket that can fly on a G80; it'll easily go higher than I'd like to chase from, so decent rate and keeping it close are certainly considerations. This is definitely an application where a Chute Release will be used once they're available - I'm just keeping the flights low in the meantime. So far I'm just flying it on D & E motors. But like a lot of my other rockets (and a lot of other flyers), I'd like to do more with it and Chute Release is exactly what I've been waiting for to do it.

I've not used them as primary recovery for anything past LPR, however,

I do have a couple HPR rockets that used streamers at apogee. First was my L2 project, Goblin: 28lb-ish on the pad, 24"x25' streamer at apogee to a 72" Iris main chute. Streamer descent rate was something like 60 FPS.

Next is an upscale of my daughter's "Bluefin," which is an upscaled Centuri (Estes) Phoenix Bird. She recovers from apogee on a big, girly 16' purple kite tail to a 48" Iris main. 10.5lb pad-ready, recovers ~50-55 FPS under streamer.

My next project, Hellraiser, will have the same streamer as Goblin. Being a bit heavier, I expect a descent rate under streamer of ~75-80 FPS.

Even though these are bigger and heavier than you're ever going to launch on a G, based upon the descent rates, I'd say that yes, it's feasible to size a streamer to serve as primary recovery on a MPR rocket.


Later!

--Coop

At TARC last spring, I talked with parents from a team that had done the streamer successfully. They said the most important thing they found was to z-fold most of the streamer, but fold the last foot or so all in the same direction. This apparently made the streamer wave back and forth much more as it fell, increasing drag. I'm also pretty sure I've seen an upper limit of a useful aspect ratio for a streamer, somewhere in the 10:1 to 20:1 range. Once the streamer was that long, making it longer didn't add much drag. That's from memory, which isn't as good as it used to be, so use a grain of salt.

That's more or less what I tried to do, but as I noted, the nylon didn't really hold the creases well. So, it pretty much pulled out straight again in the air. I'm not sure if I can try to iron it (on a very low setting), but even then, the nylon streamers have lines that are sewn into the sides which will probably not crease to the same extent as the fabric does.

Like the OP, I'm holding out for a Chute Release system before I launch my rebuilt Magnum+ with it's booster. It sims between 1600 and 3000 ft, depending on the combination of 24 mm and 29 mm black powder motors that I use. I am still using the original Estes 24" chute, which is complete overkill. I launched it as a single stage on a D12-5 this weekend, and it took forever to come down. I was thinking of cutting a spill hole in the chute, but now you guys have me considering a streamer. The weight for the sustainer with an E9-6 (the biggest engine I could use) is ~5 oz. Do you guys have a suggestion for the size of streamer that I could use for something like this?

EXPjawa said:

John, the biggest reason was that the model in question was an upscale of a much smaller rocket that used a streamer. My thinking was that if I could keep in light, I could upscale the streamer as well. However, reality has set in, and it would seem better suited to fly it on an 18" parachute. The streamer probably would work better if I could fold the nylon and get it to stay creased, but as it is, the streamer just didn't offer enough drag to be to be practical. That said, it is an 8 oz rocket that can fly on a G80; it'll easily go higher than I'd like to chase from, so decent rate and keeping it close are certainly considerations. This is definitely an application where a Chute Release will be used once they're available - I'm just keeping the flights low in the meantime. So far I'm just flying it on D & E motors. But like a lot of my other rockets (and a lot of other flyers), I'd like to do more with it and Chute Release is exactly what I've been waiting for to do it.

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This is sort of like on Mythbusters, when they try a proof of concept using a scale model. Often what works with the model totally does not translate to the upscale machine!

Seems like people want to go straight to streamer instead of use a small chute. Is more visible though. I use 1 streamer but it's because the rocket is always going straight down at ejection and kept fouling the chute etc. Have seen small Wildman fiberglass rockets used with streamer. I have a 1 pound rocket I use 18", 6-line chute on although getting some rash and may increase (but trying to avoid 24").

BDB said:

Like the OP, I'm holding out for a Chute Release system before I launch my rebuilt Magnum+ with it's booster. It sims between 1600 and 3000 ft, depending on the combination of 24 mm and 29 mm black powder motors that I use. I am still using the original Estes 24" chute, which is complete overkill. I launched it as a single stage on a D12-5 this weekend, and it took forever to come down. I was thinking of cutting a spill hole in the chute, but now you guys have me considering a streamer. The weight for the sustainer with an E9-6 (the biggest engine I could use) is ~5 oz. Do you guys have a suggestion for the size of streamer that I could use for something like this?

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Estes using a big chute usually means the rocket is delicate and needs it. For example Executioner at 8 oz. came with 24" plastic but the heavier Tomahawk at 9.2 oz. used 18", could land with quite a "bonk". But there are also cases, probably even Estes, of combining streamer with surface mount balsa fins, for some reason.