Recovery of Mini Rockets

The Rocketry Forum

Help Support The Rocketry Forum:

texasck1

Well-Known Member
Joined
May 6, 2009
Messages
50
Reaction score
0
I'm still new to Rocketry, however I have read several threads about building mini rockets using card stock and got really excited about building my own. I have a question about how you recommend to recover them.

Do you use chutes, streamers, or are they light enough that they don't need anything? If their light enough not to need chutes or streamers, do you use a motor that ejects out to light the rocket even more?

I have some design ideas that should get me started, however this is a question that I need first. Building small rockets out of card stock should fit right into my budget.
 

rstaff3

Oddroc-eteer
Joined
Jan 18, 2009
Messages
11,763
Reaction score
21
If you are talking small, very light models....

Small streamers are probably the most common, but I have numerous small rockets for MicroMaxx that just separate. They are very light and many don't go that high, so I just need them to be unstable on the way down. I don't eject the motors.

BTW by separate I mean split into 2 parts, which stay connected, most commonly by a piece of thin Kevlar twine.
 

powderburner

Well-Known Member
Joined
Jan 18, 2009
Messages
7,400
Reaction score
5
You have a couple choices here.

You could permanently attach the nose cone, block the front of the motor mount, and let the ejection charge pop the expended motor case out. The rocket is light enough that it won't hurt anything as it 'streamlines' back down. That is called featherweight recovery, and it is simple and reliable. And it is very easy to lose (my first rocket, an Astron Streak, was lost in the bushes for most of a year).

You could let the NC pop out at ejection but keep it tethered to the rest of the rocket. The whole thing would tumble as it fell, but being so small and light will not hit hard. This is called nose-blow recovery, and it is also simple and reliable. It is still a fairly small object to look for on the ground afterward, however.

You could use a small streamer, maybe a one or two foot length (you are not going to get a 10-foot streamer in that itty bitty tube, nor do you need one). In a pinch (in case you don't want to wait to mail-order some special mylar pre-cut material) you could go to your local party store and use crepe paper. It is available in many bright colors (that will help you find it on the ground) but that coloring comes off on your hands (ever help decorate before a party?), and the crepe paper gets to looking pretty ratty after a few flights. If you are still in a pinch but don't want crepe paper, try your local outdoors store for a mylar 'space blanket' (about two or three $$) and trim off a strip from one edge. The mylar is brightly silvered and is very visible in the air and on the ground. It is very durable and will last many flights. IMHO this could be the ideal choice for what you are doing.

I recommend staying away from 'chutes for your little rockets. They definitely work, don't get me wrong, but you teeny rockets will hang forever under a 'chute and will surely be blown away in any kind of winds. They could also be a problem to fold them up to get them inside a small body tube and still come out when you want them to?
 

Missileman

Well-Known Member
Joined
Apr 21, 2011
Messages
786
Reaction score
0
OK a little rocket science is called for here.
Rockets, no matter what they are made of, follow certain rules.
In order for a rocket to fly it needs to be stable. This for the most part means the center of gravity(CG) must be forward of the center of pressure.(CP)
When recovering a rocket it must be unstable. (with the exception of Saucers,cones, and pyramids)
Different methods are used to achieve this.
Shift weight, change configuration, deploy recovery device.
You mentioned ejecting the motor. This is used for tumble recovery, This only works on certain rocket designs (like the Estes Quark and Mesquito) they have fins that protrude far enough below the body tube that the CP is actually below the motor, so ejecting the motor moves the CG aft behind the CP.
For most standard designs you will need to deploy either a Chute or streamer depending on size, weight ect...
Cardstock rockets can be built very large and heavy so it all really depends on what you build.
 

Micromeister

Micro Craftman/ClusterNut
TRF Lifetime Supporter
TRF Supporter
Joined
Jan 19, 2009
Messages
15,074
Reaction score
48
Location
Washington DC
Depends on how small and light. Clones of some of the Old Centuri Cardstock stroud models like "the Point" or Vulcan can use a streamer or small 8 or 9" dia chute. the Point is it's own chute by kicking the motor on a teather it fall backwards. Very light cardstock or vellum body models can use Chutes, streamers, or even "nose-blow" or break apart recovery where the model seperates into to teathered piece and tumbles/ foats down on it's own.
Just about all Micro-Maxx models can be Streamer recovered with plain old plumbers teflon tape rubbed well with talc baby powder. the streamer also acts as the wadding. Most of these light weight models require only a kevlar shock cord instead of the usual combination Kevlar/elastic. these 2 Vulcans are were both printed on the same 110lb cardstock the larger has an 8" chute on a combination kevlar/elastic 40" shock cord. the Micro verson flys with a 12" x 3/4" white teflon tape streamer on a 38" 70lb kevlar shock cord.
Hope this helps
 

BobH48

Well-Known Member
Joined
Jan 18, 2009
Messages
3,388
Reaction score
6
A couple of things...

Ejecting engines is generally frowned upon these days.

Besides, even if they are light, having them "lawn dart" is going to damage them sooner or later.

You can get flagging tape that is bright orange, pink, or red at Home Depot or Lowes to use as streamers. 1" x 200' for a couple of bucks.

I get plastic tablecloths made for picnic tables at the dollar store. 54" X 108" for a dollar and available in at least a dozen colors. You can cut streamers any size you want. Also good for making parachutes.

I usually put streamers even in the Micro Maxx ones for visibility.

I built a 17" tall V2 from cardstock that I use a parachute in.

I agree with you that cardstock rockets are easy on the budget. The engines to fly them cost more than they do.

There are a couple of free downloadable cardstock models here:


https://www.fliskits.com/index.htm


Have fun.
 

gpoehlein

Well-Known Member
Joined
Jan 18, 2009
Messages
3,564
Reaction score
13
Another great material for micromax streamers is plumbers tape. I have found this in both pink and yellow (the yellow is for gas lines). Because it is teflon, it will not burn or melt. Thus, you don't even need wadding for these little rockets (or if you want, you can use a little piece of the plumbers tape for wadding too).

Greg
 

teflonrocketry1

Well-Known Member
Joined
Jul 31, 2011
Messages
1,627
Reaction score
4
I second the Teflon tape method, you can get wider tapes (3/4" and 1") at hardware and plumbing stores. The tapes come in several thicknesses (and colors). I prefer to use the thicker materials for streamers. Powder these Teflon recovery devices heavily with Talcum powder to keep them from sticking to themselves. I have even made parachutes from these materials which can be compressed to a very small volume. The 'chutes have a tendancy not to open when they are compressed to a minimal volume.

Bruce S. Levison, NAR #69055, A.K.A. Teflonrocketry1
 

texasck1

Well-Known Member
Joined
May 6, 2009
Messages
50
Reaction score
0
WOW, thanks for all of the great responses. That's a lot of info.

I guess i just need to go build it now.

I like the streamer recovery. Gives me visibility and slows the decent.
 

jflis

Well-Known Member
Joined
Jan 18, 2009
Messages
15,429
Reaction score
48
You've received a bunch of great advice here but i'll throw in my 3 cents (inflation and all... :p )

I invite you to stop by our site at https://fliskits.com/ and click on FREE STUFF (at the top of the page). Here you will find links to 5 different paper rockets that you can download for free and build.

They are the:

- Midnight Express
- CAUTION! Rocket Launch In Progress
- MMX Triple Threat (3 micro sized saucers patterened after our Triple Threat kit)

The Midnight Express and the CAUTION rocket come in two forms. One is pre-decorated and one is blank so that you can color it yourself :)

Also, all of these have been discussed here on TRF (a search would help you find relevant info) and also check out the reviews on EMRR for more info. These free models have been VERY well received.

Check 'em out and have a ball!

On, one more thing (nip this in the bud right now :p :p )

The FlisKits Tumbleweed kit is "tumble recovery" meaning that its center of gravity is moved after the flight is done making it unstable so that it tumbles back to earth. The Estes Mosquito kicks its motor out, but it is *still* stable and does not tumble. It is light enough that it can come in stable without damage. This is called "Featherweight recovery". Tumble recover and Featherweight recover are **not** the same.

Hope all this blather helps :)
jim
 

texasck1

Well-Known Member
Joined
May 6, 2009
Messages
50
Reaction score
0
I went to Flitkits.com last night and downloaded the "Caution Rocket". I have it all cut out and got it 90% assembled. Just waiting on glue to setup over night on the fins. It's really cool. I will post a pic when it's done. GREAT LEARNING EXPERIENCE for someone who's just learning.

Does anyone have suggestions of other sites with paper rocket plans? The ones at Flis are great :) but i would like to see other designs.

Again, thanks for all of the help.
 

JStarStar

Well-Known Member
TRF Supporter
Joined
Jun 6, 2009
Messages
2,543
Reaction score
67
Originally posted by BobH48
A couple of things...

Ejecting engines is generally frowned upon these days.

Besides, even if they are light, having them "lawn dart" is going to damage them sooner or later.



Both good points, I don't know if any currently available kits feature engine-ejection recovery. I think fire codes would be extremely dubious of the idea. Ejecting still-smoking loose engine casings into grass, etc. probably ain't a good idea.

on Point 2, I do remember my old Astron Streaks in the olden days, did come in nose-first - when the engine is ejected out, the only significant weight left in the rocket is the nose cone, so CG would move forward, so the rocket would remain stable in nose-first configuration.

It did fall fairly slowly because of its rather high drag/density ratio, but when it fell, it came in nose first. But if you launched those things on a larger engine, it would be moving pretty good when it finally came down.

I would like to meet someone, somewhere, who can actually say they ever launched a Streak on a C6-7 - which of course, every kid tried at least once - and actually got it back. Everytime I ever launched a Streak on a C6-7, it was gone forever.

I must have done it 4-5 times, but since the rocket cost 50 cents, who cares?? heheh..
 

jflis

Well-Known Member
Joined
Jan 18, 2009
Messages
15,429
Reaction score
48
Originally posted by texasck1
I went to Flitkits.com last night and downloaded the "Caution Rocket". I have it all cut out and got it 90% assembled. Just waiting on glue to setup over night on the fins. It's really cool. I will post a pic when it's done. GREAT LEARNING EXPERIENCE for someone who's just learning.

Does anyone have suggestions of other sites with paper rocket plans? The ones at Flis are great :) but i would like to see other designs.

Again, thanks for all of the help.
texasck1, check out the EMRR comparison chart at: https://www.rocketreviews.com/reviews/special/freecomparison.shtml

and a list of paper rocket reviews at EMRR at: https://www.rocketreviews.com/cgi-bin/arcbuild/arcbuild.cgi?free+paper&&search

You should get a very good start there. Also, (someone help me with a pointer...), there are some GREAT scale model paper rockets out there just *begging* to be converted to flight.

jim
 

rstaff3

Oddroc-eteer
Joined
Jan 18, 2009
Messages
11,763
Reaction score
21
Art Applehite has free plans for saucers in 13mm and MMX, and MMX mono- and bi-copters.
 

powderburner

Well-Known Member
Joined
Jan 18, 2009
Messages
7,400
Reaction score
5
Art Applewhite also has free plans posted for the Qubit, a really fun little bird that you can fly just about anywhere (literally, you could launch in your front yard and very likely get it right back).
I built several per the plans and then started making them out of scraps of matte-board (your local picture framing store will often give away odds and ends free).
 

BobH48

Well-Known Member
Joined
Jan 18, 2009
Messages
3,388
Reaction score
6
There is also a variety of free paper models at Currell Graphics. They are display models but a couple could be converted.

I made a flying model of the V2 from this site.

https://www.currell.net/models/mod_free.htm


Here is a picture of the pieces just prior to final assembly. It flies great on a B6-4.
 

Micromeister

Micro Craftman/ClusterNut
TRF Lifetime Supporter
TRF Supporter
Joined
Jan 19, 2009
Messages
15,074
Reaction score
48
Location
Washington DC
Originally posted by BobH48
A couple of things...

Ejecting engines is generally frowned upon these days.

Besides, even if they are light, having them "lawn dart" is going to damage them sooner or later.

Bob:
I don't know where you get the Idea ejecting engine casing is frowned on? It is perfectly legal and NOT a violation of the safety code to eject the spent motor casing. Only place it will cause trouble is in NAR competition or maybe with HPR reloadable casings but we'er talking about mini and micro models in this thread. Mosquitos and several other small standard size 13mm and 18mm motor tumble recovery models kick the casings. If unconfortable with a free falling casing a single wrap streamer can be taped to the casing which helps spot the casings path,
but is not necessary except in competition.

Lawn darting isn't the perfered recovery trajectory anyway As it does subject the models nose to a lot of potential damage.
if your model is changing it's geometry it should tumble reducing the sink rate.

Nose blow is another for many better way of keeping the casing in the model without the use of a streamer or chute. Here the trick is to be sure the model comes apart at a point the allows the shock line teathered pieces to drift down together sideways. This method is very good for cardstock and paper models.
 

texasck1

Well-Known Member
Joined
May 6, 2009
Messages
50
Reaction score
0
I realize that I am the new guy and that I did ask the question, but on ejecting being "frowned upon", what happens to the spent engines when you have a multiple stage rocket? The 1st is ejected then, isn't it? How is that different than ejecting in a tumble recovery rocket?

Again, I am the new guy and I am still learning. ;)
 

Missileman

Well-Known Member
Joined
Apr 21, 2011
Messages
786
Reaction score
0
UM let me try to answer.
Multiple stage rockets don't usually eject just the spent motor.
Most eject the entire booster stage fins and all.
Some use chute or streamer but most just tumble recover.
The reason motor ejecting is frowned upon is the motors are hard to see and can bonk someone on the head and you really don't want to litter anyones field with used motors.
 

BobH48

Well-Known Member
Joined
Jan 18, 2009
Messages
3,388
Reaction score
6
Originally posted by micromeister
I don't know where you get the Idea ejecting engine casing is frowned on? It is perfectly legal and NOT a violation of the safety code to eject the spent motor casing. Only place it will cause trouble is in NAR competition .... (snip)
I got the idea from reading this forum.

I know it's not a violation of the safety code but a lot of members here feel strongly about it. The subject usually comes up when the discussion centers around boost gliders.

I had gotten the impression that it wouldn't be allowed even at sport launches, but I guess I'm mistaken. That's why I haven't taken my 36 year old Astron Space Plane to any launches.
 

Micromeister

Micro Craftman/ClusterNut
TRF Lifetime Supporter
TRF Supporter
Joined
Jan 19, 2009
Messages
15,074
Reaction score
48
Location
Washington DC
Bob:
Sometimes you can get the wrong idea from some posts. for goodness sake fly your Spaceplane, I regularly fly mine, as will a a fly'in jenny, Mosquitos, quirks and a number of 3 motor clusters the pop the two outboard booster motors at burnout.. always inform the RSO/LCO to call for a heads up.

I don't know a single RSO that wouldn't let you fly your spaceplane or any motor ejection model from a sport flying range.

I try to recovery the caseing but they are completely bio-degradable, if you miss one or two it isn't a problem.

As I mentioned earlier, If you have a way to retain or add a streamer to the casing by all means do so. but don't be afraid to fly a model because it ejects the casing. It's perfectly OK...incidentally I've been "Bonked" by a C motor casing from a long way up... it wasn't even hard enough to say ouch.
 

BobH48

Well-Known Member
Joined
Jan 18, 2009
Messages
3,388
Reaction score
6
I don't know a single RSO that wouldn't let you fly your spaceplane or any motor ejection model from a sport flying range.
John,

Thanks for clearing this up for me.

I would like to take my Space Plane to a launch. It hasn't flown in almost 15 years.

I better check the elastic thread on the elevons though, it might need replacing.
 

powderburner

Well-Known Member
Joined
Jan 18, 2009
Messages
7,400
Reaction score
5
BobH48, when checking over your old SpacePlane don't forget to give your hinges a **close** inspection.
That old Estes peel-n-stick paper material usually dries out (and lets go) with age, and I would expect it needs to be replaced. I suppose you could find some equivalent hinge material at an office-supply store these days, since Estes does not sell it any more.
 

sandman

Well-Known Member
Joined
Jan 18, 2009
Messages
10,563
Reaction score
8
I flew my Astron Spaceplane 3 times at NARAM 45 with no arguments.

Of course...Carl, from SEMROC, was the RSO :D

She flew great all three times but every flight was different!

First flight she did a long graceful arc around the oval parking area and made a perfect landing in the driveway.

Second flight she did a fairly tight circle over the R/C launch sight...I got a lot of ribbing over THAT flight!

Third flight she did a fairly sharp turn to the left and went straight for about 1/4 mile...ran my behind off trying to run it down.

Man I love that thing!
 

Fore Check

Well-Known Member
Joined
Sep 24, 2010
Messages
4,263
Reaction score
7
Originally posted by JStarStar
Both good points, I don't know if any currently available kits feature engine-ejection recovery. I think fire codes would be extremely dubious of the idea. Ejecting still-smoking loose engine casings into grass, etc. probably ain't a good idea.
A few current manufacturers sell kits that feature engine-ejection. Estes and the 220 Swift (do they still make the Quark? if so, throw it in there) being a primary example.

Also the Blink rockets from RocketHead rockets.

Starlight rockets has one or two like this as well.


I also wanted to throw my 2 cents in on this tumble vs. featherweight recovery thing.

If a rocket kicks the motor, it is featherweight recovery. Very basic rule of thumb. Think about it.

The rocket would *have* to be SOOOOOOOOOO marginally stable for the engine itself to put the CG ahead of the CP that even minor nuances in finishing techniques would throw the whole ball of wax out of whack. Particularly in *small* models where "featherweight" recovery is employed, thus reducing the weight, the distances, and the margin for such error.

For a rocket to become unstable upon ejection of the motor casing, the CG would have to move *rearward* significantly enough for the rocket to become significantly unstable after losing only a handful of *grams* at the location of the engine (mind you, the rocket must still be stable after the propellant is spent. This instabilty must occur after losing the weight of only the casing, any spent BP residue, and the ejection charge and clay cap.)

Am I getting through now? I'll be *EXTREMELY* suprised if anyone here can kit a rocket that will become unstable after kicking the weight of the casing of an Estes SU A3-4T. yet the rocket was still stable under coast. And that rocket must fly to a respectable height, be easy to build (be no more than 3 or 4 FNC) and be at *most* a skill level 1. Oh, and there must be *zero* restrictions on how I finish the rocket, and no warnings necessary about acheiving proper balance prior to launch.

If we're speaking the same language now - who here has seen an Estes Mosquito, Quark, or 220 Swift come down in a "tumbling" motion? The thing was stable when it went *up*, it got *MORE* stable when it spent the propellant AND kicked the engine. It lawndarted. Light enough that no harm was done, but be honest - that's what happened.

For "Tumble" recovery, lets refer to the Estes Astron Scout. This is *still* one of my favorite rockets. With all due respect, Jim, I have not seen nor read a review of your Tumbleweed. I trust that it follows similar principles.

On the Scout, the engine is forward in the body tube an inch or so during launch and/or boost-coast. The ejection charge fires, and the motor casing is kicked back to the end of the engine hook (which extends more than an inch beyond the base of the body tube). The casing is *retained* in a position behind the position that it was during boost - coast. In this design, the weight of the engine itself helps to keep the CG ahead of the CP during boost - but then, as the CG dissipates as the propellant is spent, and then the ejection charge throws the remaining mass rearward (and then it is held, not lost) finally tipping the scale of the CG/CP relationship. The Scout comes "tumbling" back to earth. In this design, the rocket actually becomes *less* stable as the propellant is spent (which is untrue for most rockets out there.)

I hope this makes sense. I feel like I'm rambling now.....
 

BobH48

Well-Known Member
Joined
Jan 18, 2009
Messages
3,388
Reaction score
6
I hope this makes sense. I feel like I'm rambling now.....
Yup, makes perfect sense.

The old Astron Sprite used the same principle. I still have mine but it used the series III (short) engines so I have to make an adapter to use 13mm engines.

The Fliskits Tumbleweed is very similar to the Sprite but it is designed for 13mm engines.

I gotta get one of those.
 

powderburner

Well-Known Member
Joined
Jan 18, 2009
Messages
7,400
Reaction score
5
Originally posted by Fore Check
but then, as the CG dissipates as the propellant is spent
I just couldn't pass up on tweaking Fore Check-----imagine that, a CG that dissipates. I'll have to try that one at work the next time one of our projects won't balance where we want.

Actually, Fore Check is on target for almost all of his comments. It is a very fine line to be able to get a rocket design to be stable with motor and unstable without.

Was it the Astron Scout or the Sprite that did the tumble recovery thing? (We're talking about the little one with the ring tail, right?) Whatever, it is/was one very good example of how to use the expended motor case to shift CG and reconfigure a rocket. It should be a required build for everyone starting model rocketry.

As for the Mosquitos, Quarks, and Swifts, I have yet to get any visual track of one of those stupid little things beyond the instant of ignition. I couldn't tell you if they nose-dive (featherweight) or tumble, 'cause I have never seen one, I am just lucky to occasionally find one on the ground later.
 

Micromeister

Micro Craftman/ClusterNut
TRF Lifetime Supporter
TRF Supporter
Joined
Jan 19, 2009
Messages
15,074
Reaction score
48
Location
Washington DC
Most mosquitos I've recovered...very few, do indeed come down in featherweight recovery mode. I don't consider a model that bounced off the grass as a lawn dart, recovering in a slow enough manor as to cause NO damage to the model or the landing site. A really good example of a fully deployed recovery system the lawn darts every time it the old Gyroc. Helicopter recovery Maybe my backside.. Fully deployed fin/rotors she still come in way faster then I liked seeing any mod-roc...even adding a third fin/rotor she still come in fairly hot and drilled into the ground every time.
Featherweight and tumble models we've been discussing here generally come down much softer than the gyroc. I haven't seen a swift so I can't comment on it's recovery but my definition of a "Lawn Dart" is a model that comes in fast enough to stick the nose in the ground. Mosquitos and Quirks I believe refer to their recovery method as Featherweight not tumble. The only REAL tumble recovery models I can think of were the old Centuri Flutter-by, and Astron Scout and Scout II with the Scout-III being break-apart recovery. All the other motor casing ejection models were either gliders or featherweights like the Spaceman, Birdie and Streak, or Centuri Hercules, Two-bitz or even the Point which was discribed as a "Rigid Chute".
I must have missed something somewhere...why are we discussing the difference between featherweight, break-apart and tumble recovery methods? Nice to get the differences out anyway:) Personally I perfer to use the Nose-blow/break-apart method to prevent my super light weight models from coming in nose first. but sometimes ya just don't have a choice, as with sputnik's or Ghost styrofoam ball type models. In these cases I do like to use a slightly larger body tube 19mm for 18mm motors to allow a little extra room for a short mylar streamer taped directly to the motor casing. I retrofitted my old Spaceman, flyin Jenny in this fashion. I even did something similar with my Micro flyin Jenny using an ejectable pod with streamer.
 
Top