streamers on heavier model rockets???

To all...
Seeking the collective wisdom of the group here...
I'm in the process of "toy-bashing" a mini-crayon bank into a
mini-crayon rocket. Starting with the much heavier BT material,
required noseweight for stability and whatever I may do for fin
material, the final product will come in at somewhere from 5 to 8 ozs.
Pretty heavy for a 10 " rocket. Yet, it RockSim's to 1500 ft. on an E
motor.
I'd like to use a streamer recovery, but my only experience with
streamers is on rockets is the 2 oz or less range.
The questions...
1. Are streamers just as effective on heavier model rockets? That is
do they create the same descent rates as on the lighter rockets?
Packages like RockSim and online calculators (EMRR's tools) will
easily calculate a streamer size for a heavier rocket. My assumption
is that if enough surface area is presented by the streamer it will
slow down the descent rate to match that of a lighter rocket. Is that
true in practice?
2. Is there something special about a single streamer? That is if a
streamer is calc'd to yield "X" sq. inches of surface area, is it just
as effective to use 2 streamers each with "X/2" sq. inches of surface
area (all the time maintaining the standard 10:1 ratio of
length:width)?
3. And of course any other pearls of wisdom regarding streamer usage
on heavier rockets is much appreciated.
Thanks in advance.
... Bill
p.s. Remove spamfilter from e-mail addr for any private reply
Reply to
Bill K
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No. Density matters.
Yes the holy grail. Use a parastreamer. This was developed by a recovery supplier to U.S. Rockets and for purposes of discussion let's say you use a 4x40" streamer with a 12" parachute on the end of the streamer with measures to keep both ends of the streamer rigid.
Jerry
Pardon the tech post!
Reply to
Jerry Irvine
I've built several 29mm Black Brants which normally weigh in at about 6 oz. without motor (probably near 8 oz. with an expended G125/G80/G40 ad nauseum). Only popped a fin off once...
... when I found 'em... :-)>
I had a scratch Aura that was probably 9 oz. (IIRC) that I flew for quite some time on streamers.
They come in kinda quick and the airframe - forward of the motor mount which provides for stiffness - can get cinched from the bounce.
Bill K wrote:
Reply to
Gene Costanza
No doubt due to re-entry stress..... ;O)
But seriously, what fin material did you use and how were they attached?
Reply to
BB
This is the one that's about 2.5" diameter? I've done a couple of these, and flown them on 18mm motors. Nothing less than a C5-3|C6-3 but they do very nice on a D13-4. Mine have clear plastic fins to not detract from the crayon-like appearance.
The tests I've read (including the one I've done) dealt with NAR competition models. Nothing big and heavy. I think larger streamers reach a point of diminishing return.
There's LOTS of funky things you can do to streamers that make generalizations of this type meaningless.
I wouldn't consider a streamer on this size crayon bank. You're almost certain to crack fins on landing.
Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!
Reply to
Bob Kaplow
You might consider using an 18" parachute with a 6" hole cut in the center. If you use an Estes 'chute just cut out on the dotted line.
Karl Perry QUARK, Cincinnati, OH
Reply to
KG8GC
snip
Ahhhh, no. The ratio between the drag of the streamer and the weight of the model matters. Density? WTF are you speaking of?
Reply to
Quilly Mammoth
You're right on that. The uniqueness of the crayon bank makes it a fun demo rocket for kids. I've done a couple of space themed afternoons for my kids elementary schools (model the solar system, look through a telescope, etc.) and always like to end with a rocket demo. Because of space limitations I'd like to use streamer recovery.
All great points. And heck I'll give it a try. Maybe try a streamer - small parachute combination.
Thanks Bob.
... Bill
Reply to
Bill K
ROCKETdensity since the streamer is typically a small fraction of rocket recovery drag (competition rockets being the exception).
Streamers are primarily for visibility and positioning the rocket during recovery. Sometimespositioned badly if itmakes the rocket more stable on the way down and aiming the fins at the ground.
Jerry
Reply to
Jerry Irvine
Jerry What do you think of the streamer tied to the balance point to provide the rocket with a horizontal profile on recovery? Just as the small comp. rockets for duration.
Ken
Reply to
Kenneth Jarosch
That makes a HUGE difference.
Reply to
Jerry Irvine

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