Quantcast

Looking for tips on streamer recovery in larger LPR rockets

The Rocketry Forum

Help Support The Rocketry Forum:

Bill S

Well-Known Member
Joined
Aug 6, 2019
Messages
544
Reaction score
225
I'm considering trying out streamer recovery for some of my rockets, but wanted some advice. Launch conditions around here have been not so hot the last couple months; 10-15 mph winds, constantly changing wind speed and direction, resulting in 2 lost rockets. I've tried parachutes with spillholes, not much help. I have seen some people pull off higher flights (1200-1500 ft) using streamers, but I'm not sure the best way to do it.

I'm aware the optimum width/length ratio is 1:10, but I'm not sure as to the best materials to use, and what is a good descent speed to aim for.

Right now, I'm looking at trying streamers out on my Squirrel Works Arapahoe-E and possibly my Estes Vapor. I haven't been able to fly either of them higher than about 700' due to the risk of losing them. The Arapahoe-E is on a 15" parachute, and the Vapor is on an 18".

Using Rocksim, on the Arapahoe-E, it says a 3.2" wide x 32" long, with a descent speed of 34 feet/second, which seems kind of high compared to a parachute recovery.

I like the idea of mylar for increased visibility, but if something else will perform better, I'd consider it.

Thoughts?
 

shawn_rocket

Well-Known Member
TRF Supporter
Joined
Jul 14, 2020
Messages
212
Reaction score
129
Location
Maplewood, MO

Handeman

Well-Known Member
TRF Supporter
Joined
Jan 18, 2009
Messages
7,751
Reaction score
346
Location
Stafford, VA
What size spill holes are you using on chutes. The 12" chute I used in those conditions had a 8"-9" spill hole. A 12" hole in a 18" chute should work.
 

Bill S

Well-Known Member
Joined
Aug 6, 2019
Messages
544
Reaction score
225
I was using a 4" spillhole on a 18" parachute, and none on the 15" as I recall.
 

AfterBurners

Well-Known Member
Joined
May 8, 2012
Messages
7,661
Reaction score
394
Location
Dallas Texas
A couple things to take into account is the landing surface? 34 feet per second could do some damage. What about an X Form chute? That might help without risking the damage?
 
Last edited:

Handeman

Well-Known Member
TRF Supporter
Joined
Jan 18, 2009
Messages
7,751
Reaction score
346
Location
Stafford, VA
15mph winds will move your rocket sideways a specific distance in a specific amount of time. 22 ft of down wind distance per second in the air. It doesn't matter if you use a chute or streamer, both will move sideways with the air mass at the same rate.
A streamer will only get you to land closer to the pad if causes the rocket to descend faster, less time in the moving air mass. How fast do you want to hit the ground?
 

Bill S

Well-Known Member
Joined
Aug 6, 2019
Messages
544
Reaction score
225
Gotcha. I'm having a hard time justifying a $125 Jolly Logic chute release for low powered rockets though, plus it won't fit in the vast majority of rockets I own (requires a BT-60 sized tube minimum when I checked it out).
 

David Schwantz

Well-Known Member
TRF Supporter
Joined
Jul 23, 2018
Messages
1,950
Reaction score
837
Location
MN
I fly a lot of streamers. From 13mm stuff up 4" DIA. what are your questions? I like to roll mine to pack them. I have used mylar, nylon, and ribbon from JoAnns fabrics. All work. Top flight makes good ones as does Rocketman. On the small stuff I used a kevlar loop, fold over the streamer end and use contact cement to glue the flaps. Bigger stuff gets sewn. I have used 2 streamers at a time. Yes, they will come down faster. If you have your fins angled above your body tube this helps with less damage. Gotta dig some dirt out of the Aeropack retainer sometimes.
 

Rob702Martinez

Zip-Tie Oversight Committee
TRF Supporter
Joined
Dec 30, 2015
Messages
1,347
Reaction score
327
Location
Las Vegas
Has anyone ever tried a small drouge at the end of a streamer in any size flight?
 

Bill S

Well-Known Member
Joined
Aug 6, 2019
Messages
544
Reaction score
225
Rob, no never even heard of such a thing. How does that work?
 

Tractionengines

Well-Known Member
TRF Supporter
Joined
Aug 29, 2020
Messages
78
Reaction score
25
Location
Northeast Ohio
A parachute on the end of the streamer could defeat the purpose.... you want the streamer "flipping and flopping" around in the air steam causing lots of wind resistance... a Parachute at end opposite the attachment to the rocket, could line up the parts, and slow the streamers "movements" leading to faster decent speeds.
 

Rob702Martinez

Zip-Tie Oversight Committee
TRF Supporter
Joined
Dec 30, 2015
Messages
1,347
Reaction score
327
Location
Las Vegas
A parachute on the end of the streamer could defeat the purpose.... you want the streamer "flipping and flopping" around in the air steam causing lots of wind resistance... a Parachute at end opposite the attachment to the rocket, could line up the parts, and slow the streamers "movements" leading to faster decent speeds.
Yeah that's what I was thinking too. Just a thought that came to mind when reading this thread. Most of my birds use streamers for the drouge.
 

prfesser

Lifetime Supporter
TRF Lifetime Supporter
Joined
May 7, 2017
Messages
1,641
Reaction score
1,626
Location
Murray, KY
I flew a min-dia 29 mm that used a 25 foot pink plastic marker tape as a streamer. Objective was not to slow for recovery---it was a sturdy rocket, fiberglass fins---but to make it easier to find in the sky and on the ground. (I have terrible eyesight, floaters abound).

Best -- Terry
 

BABAR

Builds Rockets for NASA
TRF Lifetime Supporter
TRF Supporter
Joined
Aug 27, 2011
Messages
7,353
Reaction score
2,295
Certain rockets lend themselves to streamer recovery by fin placement.
Arapaho-E and Vapor May be good choices because the fins don’t extend tailward of the body tube. Rockets like the Alpha and other rockets with trailing fins don’t do so well.

Asymmetrically finned rockets can also recover very well on streamers as they come down fin side up.

Examples



 

CrocketRocket

Well-Known Member
Joined
Nov 28, 2020
Messages
46
Reaction score
10
Normally, rockets separate into a small nose cone section and much longer body tube and fins section.

Does anyone know if separating the rocket into two parts closer to the center of gravity changes how a rocket falls? Perhaps this creates more of a tumbling action for the tail section with fins? As opposed to the rocket plummeting fins first down towards the ground.

I have no idea if this is true. (I'm not suggesting Bill cut his Arapahoe-E and Estes Vapor in half.)

But as I try to do higher and higher flights, my small field is going to force me to rely on streamers and parachutes with large spill holes.

I'm in a very similar predicament as Bill S.

Seems like fin shape can help a lot.
 

cbwho

Well-Known Member
Joined
Mar 20, 2019
Messages
143
Reaction score
62
Location
MN
I fly streamers or chutes with spill holes. I find that it's easier to repair a broken rocket than repair one that drifted too far away...
 

CrocketRocket

Well-Known Member
Joined
Nov 28, 2020
Messages
46
Reaction score
10
Bill,

One photo is an example a standard streamer recovery. Tail hitting the ground first. Most of the rocket's mass is in the same body tube section as the fins. You can easily imagine all the energy of striking the ground passing through the fins. If that rocket is descending fast, it would be no surprise if a fin was damaged.

In the second photo, a larger portion of this rocket seems to be on the nose cone payload half. (Yes, it is on a parachute, but imagine if it was on a streamer). The fin section seems to maybe be picking up more drag, (perhaps a better drag to weight ratio?). In this scenario, it seems LESS likely that a fin would be damaged when hitting the ground.

I think some fin designs can also encourage the fin / body tube section to fall in a more horizonal position rather than vertical. This would also might be beneficial. Think of the difference between terminal velocity of a normal skydiver in belly flop position versus a skydiver in head first freefall. There is a big difference in terminal velocity of those two positions. But landing horizontal would definitely put torque forces on a fin. . . probably not good.

I do not have enough rocketry experience to know yet what fin shape and tube length would reliably cause a horizontal body tube position during streamer descent. But it's something I'll be looking out for as I try to hit my altitude goals in my small limited sized field.

Whenever building or designing ANYTHING, I prefer to follow the KISS method and keep things simple. These rocket pros probably know a great dimension for reliable streamer recovery for your rockets. As long as your future rocket builds avoid swept back fins, you should probably be okay.
 

Attachments

BABAR

Builds Rockets for NASA
TRF Lifetime Supporter
TRF Supporter
Joined
Aug 27, 2011
Messages
7,353
Reaction score
2,295
You can also rig a two point external harness with a forward and rear attachment point, streamer attaches to the middle to “force” the rocket to descend horizontally. Particularly if you use asymmetric fins, with all the fins on one side of the rocket, you can descend faster with lower probability of breaking a fin (or something the rocket lands on!)

Asymmetric fins also cause spiraling, which looks cool AND reduces altitude, in this case let’s you use bigger motors in smaller fields.

If you REALLY want to go with bigger motors on smaller fields, think saucers.
 

Dane Ronnow

Well-Known Member
Joined
Dec 16, 2020
Messages
82
Reaction score
33
Location
Las Vegas, NV
As long as your future rocket builds avoid swept back fins, you should probably be okay.
I had to chuckle when I read this. I'm building a 40" rocket on a BT-80 airframe, with some seriously swept fins. Why? Because they look cool. Yes, there are far more efficient fin designs. And yes, I experimented with these in OR. But I kept coming back to the swept trapezoid, because . . . (dare I repeat myself?) . . . they look cool.

The fins are .125 balsa, papered, and still pretty much guaranteed to at least chip a trailing corner on landing. I spent more than a little time thinking about trailing edge reinforcement—a stirrup of sorts—with scrap cardboard (.063 x .125 x 2 or 3 inches) that would wrap the corner between tip and trailing edge. In the end, that would probably do little to prevent fin damage, and would just add weight.

The answer, at least for me, was to slow the descent. In OR I spec'd a 30" parachute, and got the ground impact down to ~6.44 mph (9.44 fps)—little more than a brisk walking speed. From any other flying field I could kiss the rocket goodbye, but I live 20 minutes from the Jean Dry Lake Bed south of Las Vegas. And there, you really can't lose your rocket—at least one that peaks at 1900 feet—unless it drifts close to a mile. (I simmed a flight with three E9s in 10 mph of wind, and in a descent from 1900 feet, the drift is 2200 feet. Even if I flew in 10 mph winds, which I don't, recovery would not be a problem.)

Anyway, I decided to go all-out and make the parachute myself (I know how to sew rolled hems and flat-felled seams)—an elliptical with 12 gores, alternating white and blaze orange (of course), with a 6" spill hole.

After all, the only thing cooler than swept fins is a great looking parachute bringing everything back in a (hopefully) soft touch down.

Test Rocket OR design window.JPG
 
Last edited:

BABAR

Builds Rockets for NASA
TRF Lifetime Supporter
TRF Supporter
Joined
Aug 27, 2011
Messages
7,353
Reaction score
2,295
forward swept fins look cool too, and are a lot more durable, if slightly less efficient.
 

BABAR

Builds Rockets for NASA
TRF Lifetime Supporter
TRF Supporter
Joined
Aug 27, 2011
Messages
7,353
Reaction score
2,295
Until you hit the speed limit
I am a low power guy, so no experience with this, are forward swept fins more subject to flutter or breakage st higher velocities? I rarely exceed the speed of balsa.
 

Nytrunner

Pop lugs, not drugs
TRF Supporter
Joined
Oct 15, 2016
Messages
7,547
Reaction score
3,109
Location
Huntsville AL
Close! Forward swept fins are more susceptible to excessive fin divergence.

Terrible summary:
-Flutter is the dynamic back and forth of the fin (imagine twanging a tuning fork)
-Divergence is the elastic twisting of the fin by the aero forces. (Forward swept fins get twisted back against the fixed root zone, aft swept fins stream back from the fixed root zone)
 

RobertH3

No need to buy stands after a launch day!
TRF Supporter
Joined
Apr 18, 2020
Messages
165
Reaction score
190
Location
Central Indiana
I've been building what I call Muncie rockets. Special built for bad landings. Always windy and landing rockets are gravitically attracted to the blacktop and gravel at our field. Heavy duty fin joints with glue rivets or TTW, and basswood half rounds on fin edges. Papered too. Large LOC thin mil streamers (4x40, 5x50 etc). We'll see how they survive... I guess build them tough and bring them down quicker. Lots of ideas in the thread.

Cheers / Robert
 

Latest posts

Top