Please Post Your Drogueless Descent Rates Here.

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K'Tesh

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When Jolly Logic released the Chute Release, John Beans requested that people would post their drogueless decent rates so we can perhaps learn about what is a realistic decent rate for OR (and possibly RockSim) simulations. To date, nobody has in that thread. So, Let's make it easy to find. Please post your decent rates here.

We need to know what your kit's specs are (.ork or .rkt sims help), and how it performed after separation.

Thanks!
 

ksaves2

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When Jolly Logic released the Chute Release, John Beans requested that people would post their drogueless decent rates so we can perhaps learn about what is a realistic decent rate for OR (and possibly RockSim) simulations. To date, nobody has in that thread. So, Let's make it easy to find. Please post your decent rates here.

We need to know what your kit's specs are (.ork or .rkt sims help), and how it performed after separation.

Thanks!
Uhhhhhh, Me thinks a lot of folks are flying the chute release without any additional electronics. That said, I agree it would be interesting for those that have a recording device along for the ride post their descent rates. That of course would
depend on the rocket and the size of the reefed chute packet. A good sized reefed chute may act as a pseudo streamer of sorts. Kurt
 

SCrocketfan

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A few data points from my two BAR Crayon kits (both about 40 oz loaded, 4" diameter, nose break):
Drogueless with 48" bundled Spherachute ~40-45 ft/s (2 flights)
12" drogue at nosecone with 48" bundled Spherachute-40 ft/s, much more stable descent and more responsive main deploy (3 flights now)
15" drogue at nosecone with 50" bundled Top Flite ~35 ft/s (1 flight)

While the drogueless rate and rate on the drogue are about the same, I'd definitely recommend a drogue on anything heavier than a Leviathan or so, just to stabilize the descent. With no drogue, the Crayon oscillates between the nose leading the booster and the booster leading the nose, and also drifts more horizontally ("side gliding"). With the drogue descent is much more stable and vertical. That said, drogueless is really nice on light rockets to simplify recovery.
 
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dhkaiser

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Flew a Estes Mammoth today with a Chute Release and Alt3, almost 1100ft, see Alt3 graph...

edit: drougueless decent = ~38ft/s, on 24" chute ~20 ft/s.

Short Mammoth FlightGraph.jpg
 
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FastAsleep

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Most of my flights with the chute release have included the a Jolly Logic II and some tracker (mostly BRB900) so I don't have a drogue descent rate for those flights.

However, the Lava Laguna is a night rocket with 4 NiteBows, 2 fore and 2 aft so I have to use a RRC3 to separate it at apogee and until now had used cable cutters to deploy the main. With the Chute Release, the setup was so easy even with a 50" Top Flight chute and paralite.

Accoding to the LCD on the RRC3 the drogueless descent rate was 51 fps (and main at 22 fps). See OR and mDACS screen caps below.

Lava Laguna OR.jpgLava Laguna mDACS.JPG
 

John Beans

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Great thread!

If anyone knows their flight weights, those would be good to list, too. Many people get nervous when they have a 5 pound or 9 pound rocket, and worry about the tumble rate.
 

DavidMcCann

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Ballpark weights, all were with payload bays and about 15' cords. I have video of the Screech and villain falling with no drogue if anyone's interested.


6 pound 4" rocket






3" 6 pound MAC villain. This guy comes in HOT.



5 pound 4"


The rest of these only graph G load :/ Unless I can't figure out the MARSA software.

nine pound 3"


3" Villain 6 pound





The following 4 are from my 2.6" screech, 7.5 pounds loaded, so ballpark 6 ish burnout?
k1127


J510W


K1127 (ok I posted this, looked at it stupid and then realized it blew the main at 8700' ><

J1026 LC




Hope these help. I like drogueless, and think it's fine if you're balanced right and the rocket isn't coming in ballistic dragging the NC behind it.
 
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K'Tesh

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Great thread!
I though you'd get a kick out of it.

Thanks to everyone who's posted their statistics. This is going to help a lot of people!

Pointy Side UP!
 

kevinkal

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Estes Pro Series II Nike Smoke. AeroTech RMS 29-40/120 with a G76-10G reload. Generally stock build, added a light parachute shelf and replaced the estes shock cord with a 10' of 900# tubular Kevlar. Weight was about 17 oz without the motor. Had both the JLCR and a JLAltimter3 attached to the chute and nosecone. Stock 24" chute.
Descent Rate without a drogue was about 41 ft/sec. (1319 ft / 32 seconds) = 41.2

FlightGraph.jpg
 

DavidMcCann

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Videos at realtime speed, just for giggles- Yellow rocket is the Villain, Blue/green is the Screech. I've got no problem popping these guys at 80 fps, and pretty sure thats the speed my 9 pound DS is falling as well. Chutes for the screech and villain are 4' Rocketman or 48" fruity chutes Iris. DS is on the iris.

Villain (3 flights)-
https://youtu.be/mXfD646uURc
https://youtu.be/euJD8tX0Sew

Screech (2 flights)-
https://youtu.be/rCW0Ot4SfFw
 
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kevinkal

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Rocket: Estes Pro Series II - Mega Der Red Max
Build Details: Stock plus small eyebolt in fwd CR with short length of Kevlar and a swivel inside body tube to prevent shock cord wind up during droguless descent using the JLCR.
18" Nomex Chute Protector. Weight also includes the JLCR and a JL Altimeter 3.
Notes: This setup falls slowly, and the booster with the big fins falls in horizontal orientation and spins quite a lot when falling without the chute.
Weight w/o Motor: 36.3 oz

Weight with a G80-7T as flown in the video and plot below: 40.8 oz

Droguless Descent Rate: 33 ft/sec

The chute took a few seconds on open in the plot below.. and as you can see.. the chute only slowed it down a little more than the droguless descent rate.
Will Ferry posted a nice video with zoom where you can see the droguless descent and also the chute release let go.. then the chute take a few seconds to open. Here's a link:

https://photos.google.com/share/AF1...?key=OWszTmJlSGVZeVBaQTFlUnFheV95Q1ppZ1RzQXdR

20160416 TCC MDRM G80-7T.png
 
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cerving

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I've flown a number of smaller rockets drogueless (wouldn't do it with anything above 3#...), and the typical descent rate is 40-50 fps. That seems to be about what everybody else sees, too. You want the rocket to break roughly in the middle, and the pieces should weigh about the same. Something light and large like a Partizon would probably come down slow enough drogueless that if the main didn't come out you'd probably get it back unharmed.
 

DavidMcCann

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I and many people I know routinely fly 6-15 pounders drogueless, Any reason you suggest 3 pounds? Larger rocket, larger chute, absorbs the speeds just fine to me.
 

Steve Shannon

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I and many people I know routinely fly 6-15 pounders drogueless, Any reason you suggest 3 pounds? Larger rocket, larger chute, absorbs the speeds just fine to me.
I absolutely agree. Even larger is fine. A large rocket in a flat spin can fall slower than the same rocket under a drogue. A drogue usually prevents a flat spin. Unfortunately, I don't know how to reliably cause flat spins.


[emoji1010] Steve Shannon [emoji1010]
 

cerving

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I and many people I know routinely fly 6-15 pounders drogueless, Any reason you suggest 3 pounds? Larger rocket, larger chute, absorbs the speeds just fine to me.
It's size (cross sectional area) vs. weight. Most larger rockets have a disproportionately larger amount of weight, mainly because they're usually fiberglass vs. cardboard. That means that their drogueless descent rate will be higher. Does it mean that it's unacceptably high? Probably not, but I tend to be a little conservative in these matters.
 

DavidMcCann

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It's size (cross sectional area) vs. weight. Most larger rockets have a disproportionately larger amount of weight, mainly because they're usually fiberglass vs. cardboard. That means that their drogueless descent rate will be higher. Does it mean that it's unacceptably high? Probably not, but I tend to be a little conservative in these matters.
and usually proportionally bigger fins. I Don't have a CR, so no dog in this fight, but I wouldn't have an issue dropping a ten pounder with one using motor deploy and and no traditional altimeter.
 

ActingLikeAKid

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Don't have descent data but here's a video of my Wildman Punisher popping a CR'd chute at apogee then opening at 300(I think? Maybe 400?) It was a windy day so the flight arced a bit near the top. Even with the CR, it was about 1/3 of a mile (on a 1500' apogee). Spun like CRAZY on the way down, but that didn't seem to hurt anything.

Will post more data when I finish building my Eggtimer. SMTs are HARD.

[video=youtube;ehmiTlywKfI]https://www.youtube.com/watch?v=ehmiTlywKfI[/video]

(Side note - watch the clouds after it lands. Doing that was fun)
 

billdz

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This IQSY Tomahawk was coming down really fast (over 150 fps, is that too fast?) until JLCR released the chute exactly at 500 feet for a nice landing. Weight was 3480g with the I-500 motor (2900g with no motor).

Tomahawk graph.jpg
 

Handeman

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I only fly one rocket drogueless, that's a 3" LOC tube scratch built that weighs about 4 lbs.

I have no problem flying a JLCR on a motor eject because the bundled chute works like a drogue and controls the decent.

I do have a problem with flying large DD rockets without a drogue and allowing the majority of the flight, apogee to main deploy, to be flown with NO control of the flight profile. Chaos will eventually get you! Sure, a well balance rocket will drop right without a drogue, until it doesn't. Without a drogue to set and control the flight profile during the drop, there is nothing to prevent the main from deploying under the fin can and everything come crashing down.

I know flying HPR is all about risk management. If you are OK with risking a crash on a 15 lb rocket because the drop from apogee didn't happen the way it had the previous 5 or 10 flights that's OK. The risk of injury is probably super small, the risk of damage to the rocket might be higher, but still acceptably small.

I've just seen too many failures or near misses because of drogueless flights that I won't do it except on small DD flights. Again, risk management.

BTW, just because the LCO says congrats and great flight over the PA, doesn't mean the flight wasn't a near miss. </rant off>
 

LithosphereRocketry

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Recently flew my scratch Vesta on a G80. Standard LOC 1.6" tube, ply fins. 1lb loaded, like 12ish oz w/o motor. 40" long. That thing left in a hurry!

Very similar to a beefy Estes Star Orbiter.

View attachment vesta-camera.ork

Anyway, estimated drogueless speed 50ft/s.

[video=youtube;8FsVxMhPEPQ]https://www.youtube.com/watch?v=8FsVxMhPEPQ[/video]
 
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afadeev

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PML BumbleBee flying on J270W motor, 22530g / 5.0 lbs.
Hit 3572" altitude (lower than simmed, due to suspected weak motor that finished burn earlier than the projected 2.6 secs).
At apogee, ejection charges deployed JLCR folded 48" chute that had stabilized descent rate to 52 fps. 48" folded chute / semi-streamer descent rate is functionally equivalent to that of a 12.5" drogue chute, per OR simulation.
Once JLCR release at 300", the descent rate slowed down to 21 fps.

FlightGraph.jpg

a
 

ActingLikeAKid

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I have some really good and unique information to add!!
My "Mega Vector Force" had an Altimeter 3 in it when it failed to deploy. Dry weight is about 1400g. With a failed deployment, its initial descent rate was 130 fps; ground hit was at 190 fps.* Since this is a stable rocket with a heavy nose and nice big fins, I'd think it just arced over gracefully at apogee and came straight at the ground.

With the altimeter 3 in place and a successful deployment with the Chute Release set to 400', initial descent was 63 fps and ground hit was at 22.7 fps.
In OpenRocket, I have a "faux drogue" parachute to simulate the post-break tumble that I've now tweaked so that it will give me that descent rate. My rocket is 1.78m long; lower section is 57.5 mm, upper section is 39.5mm.

*sidebar - a shout-out to Always Ready Rocketry; the fin can and a good chunk of airframe was quite usable after that crash)
 

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