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Recommendations on Drogueless vs Streamer

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BackSeatBryce

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Hey everyone,
I'm working on a 3" min diameter rocket, and I'd like your opinion on going drogueless vs using a streamer for most of the descent until the main deploys. The nosecone separates from the body tube, and that's the only separation point. I'm going to use cable cutters to keep the main wrapped in a nomex burrito until deployment. My expected altitude is ~35,000 ft.

Total rocket weight after motor burnout: 12.5 lbs
Weight of nosecone and everything in it: ~1 lbs
Weight of body tube and everything in it: ~11.5 lbs

Length of nosecone (including shoulder): 20.3 inches
Length of body tube: 55 inches
Number of fins: 3

I've never used a streamer, though I have flown another rocket a number of times with a standard DD config using a drogue and main chute. If you recommend a streamer, can you help me determine the width and length? I haven't been able to find any good design guides for sizing a streamer properly.

Thanks in advance,
Bryce
 

Eric

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I love a big streamer. I always heard that droguless could lead to parts tumbling and smacking into each other.
FB_IMG_1555291879206.jpg
 

BackSeatBryce

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Great photo! Is that a Wildman kit? What size streamer would you recommend for my design?
 

Eric

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That is a 3" Black Hole from Mach 1. Its descent weight was about 9 pounds. That streamer is 1'x24' made by BAMA recovery. In that photo the streamer folded over the shock cord when the main opened. A little longer or wider streamer for that weight would have gave me a little more drag. Then both haves would have fell below the streamer.

FB_IMG_1555290014313.jpg
 

Bat-mite

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When using a Cable Cutter (or the modern, non-pyro equivalent Jolly Logic Chute Release), the balled up main acts as a drogue until you pop it loose. So, you already have your answer.
 

mpitfield

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It depends on the design.

I have a nose-heavy, relatively large fin area booster, single spilt dual deploy rocket that uses a JLCR for main and an baro altimeter for apogee. If I do not use a small 9" drogue then the descending package lines up, nosecone straight down followed by JLCR bundle, harness and the booster. It comes in hot until the JLCR goes off and the booster heads right through the main.

I am a big fan of the right sized drouge in the right place, but you need to dial it in. Typically my first two launches on a new build are 3-5,000' so I can see all the laundry deploy, and adjust as needed.
When using a Cable Cutter (or the modern, non-pyro equivalent Jolly Logic Chute Release), the balled up main acts as a drogue until you pop it loose. So, you already have your answer.
 

timbucktoo

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When using a Cable Cutter (or the modern, non-pyro equivalent Jolly Logic Chute Release), the balled up main acts as a drogue until you pop it loose. So, you already have your answer.
I’ve seen this many times where the rocket comes in pretty hot, almost too hot when main does deploy.
 

BackSeatBryce

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Thanks everyone for the replies. Buddy, I see your extreme streamers list descent speed vs weight. Do you have that same information available for your standard streamers?
 

Buddy Michaelson

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Thanks everyone for the replies. Buddy, I see your extreme streamers list descent speed vs weight. Do you have that same information available for your standard streamers?
I do not have any data on the smaller ones, I’ve flown every size, but not enough flights to have consistent data over a long period of time. The extreme streamer data had came from about 10 different customers which helped me form those numbers. I have found this calculator to be somewhat helpful: https://www.rocketreviews.com/streamer-calculator.html
 

Rocketjunkie

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If you want the visibility of a streamer but the descent rate is too high, use a parastream. Attach a small chute to the free end of the streamer.
 

Buddy Michaelson

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If you want the visibility of a streamer but the descent rate is too high, use a parastream. Attach a small chute to the free end of the streamer.
A parachute attached to the top of the streamer would lower the Cd as the streamer wouldn’t me able to take new air on as it’d be held tought.
 

patelldp

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I've flown drogue-less for 13 years, or as Graydon Pihlaja from CTRA-NARCONN called it..."Drogules" (pronounced dro-gulls).

Formula 38 to Hawk Proteus...no drogue, no problem.
 

Rocketjunkie

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I've flown drogue-less for 13 years, or as Graydon Pihlaja from CTRA-NARCONN called it..."Drogules" (pronounced dro-gulls).

Formula 38 to Hawk Proteus...no drogue, no problem.
I fly a lot of my rockets drogueless. However, the OP has only the nose cone coming off at apogee. The remainder of the rocket is almost certainly stable and will cause problems. I got away with it here:
You can see the body stabilize and shoot past the nose, only the nose pulled it sideways. In extreme cases, the body stays stable and the nose just trails behind it.
 

OverTheTop

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Drogueless dual deploy is how I normally fly. Blow the NC off at apogee, with the chute staying in a deployment bag inside the airframe. Blow the bag out of the airframe at 2000'.

Just make sure that there is enough drag on the NC. I make sure there is a nice bit of nomex cloth tied to the NC. I had one come in with the NC tucked in behind the airframe, before I used larger laundry on the NC.. The main came out and pulled everything up nicely, for a nominal landing. Only a 3D printed transition was cracked, and reprinted for future flights. So the moral of the story is to make sure there is enough drag on the NC so everything comes in flat.
 

Handeman

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I fly my Callisto with a JLCR and the chute bundle acts as a drogue. The rocket comes down very stable and consistent in a vertical position with the fins first and the chute bundle and nose cone following. It comes in much faster than any of my standard DD rockets with or without a drogue.

I would recommend a few 3,000 ft flights with a JLCR or cable cutter so you can watch the fall from apogee and tune the main opening altitude and overall recovery profile.
 
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