Horizontal Spin Recovery - with Magnus Effect?

[BABAR]

IMHO that would be the CG.

I'm thinking about two ports, on a diagonal, 3/8" apart, at the top. This will release the ejection gases slightly more slowly and less violently, fan the gases out in a wider arc, and still act to push the front preferably horizontal.

I like the idea. Using two holes lessens the "puff" compared to an individual hole (one thing that scares me is the one hole being insufficient to prevent tube rupture) and spreads out the force a bit more.

You are going to be a challenging partner on this forum to keep up with! There are not that many of us willing to color outside the lines.

 

[BABAR]

IMHO that would be the CG.

If so, then your body tube crimp is more difficult to blame on the "port thruster"(ooooh I like that, sounds like something from Star Trek!)
I was thinking the inertia of the fin can was greater than the body tube, so the tube bent at the fin can/tube junction.

 

[Ez2cDave]

One day I asked him about the Menehune. He changed color, went stolid and refused to talk about it.

Dotini,

From what I have read, it seems that the "Menehune" are the equivalent of "Hawaiian Leprechauns".

https://www.to-hawaii.com/legends/menehune.php

Dave F.

 

[icyclops]

Dotini,

From what I have read, it seems that the "Menehune" are the equivalent of "Hawaiian Leprechauns".

https://www.to-hawaii.com/legends/menehune.php

Dave F.

And where is the pot of gold

 

[icyclops]

Respectfully disagree.

Musk’s Falcon 1 finish wasn’t exactly Michealangelo, but it was painted with a logoView attachment 459402


Good reasons to paint model rocket prototypes include visibility (I launched an unpainted FlutterBye in fall. Unpainted body tubes and balsa look a lot like autumn leaves. I found the upper half with the nose cone. The thing only went up about 200 feet), aerodynamics (smooth light paint jobs can fly higher), and water resistance (wet grass warps bare balsa in a hurry.). Plus some designers may look at a paint scheme like an autograph on their designs. So while I choose to fly (my rockets) naked, it’s very much an individual choice.

in the case of horizontal spin, Dotini is doing something generally not done before (at least according to Tim Van Milligan’s book.). Not that Horizontal Spin is done much at all (to my admittedly limited knowledge,@Dotini and I are the only ones at least in recent years to post on this technique.). But per Tim’s book and in my flights, usually the nose is blown and recovered separately. @Dotini is doing it with nose cone intact, he’s “borrowing” or “adapting” a trick from Back Sliders to interrupt the initial streamlined forward trajectory. Presence or absence of paint may make a bigger difference in these rockets than most, as it will definitely move CG well forward (since his are classically long skinny rockets). Likely there is a point where the forward CG overwhelms the effect of spin and the rocket “refuses” to turn horizontal. Also the added inertia of the painted tube may make it more likely to flex.

back to theory and practice, to stay on topic.

what if we placed two ports, equally spaced forward and aft of the CG, pointing in opposite directions? I don’t think this would ELIMINATE bending stress, but it might distribute it more evenly across the airframe (or conversely make it even worse, focusing it right AT the CG.....course you could but a coupler there, but it’s gonna cost you some mass and may just focus the bending force at the fore and aft marines of the coupler....)

another unknown is just how far forward does the port have to be? Could you put a port in the rear, just forward of the engine block, and blow the tail of the rocket sideways enough? Would that cause more or less lateral bending stress?

Disagree about what? Paint the thing and fly it already. Geeezzzz

 

[Dotini]

I like the idea. Using two holes lessens the "puff" compared to an individual hole (one thing that scares me is the one hole being insufficient to prevent tube rupture) and spreads out the force a bit more.

You are going to be a challenging partner on this forum to keep up with! There are not that many of us willing to color outside the lines.

I've been out of touch with model rocketry for over 30 years. It's surprising to me that "not many are willing to color outside of the lines". But really what are the lines? The code(s)? The stratification of model rocketry into fixed categories? Being a maverick innovator is no guarantee of success, but is great amusement at this time of pandemic. Believe it or not, my next rocket could have 18 fins.

I was thinking the inertia of the fin can was greater than the body tube, so the tube bent at the fin can/tube junction.

I'm not yet able to really know all about this. It could be a mix of several things. 1) Mishandling the rocket? 2) Inherent weakness of the long, thin rocket at this particular point? This seems a very common failing of this generic type of rocket. 3) Whiplash induced by sideways ejection charge?

Paint the thing and fly it already. Geeezzzz

X-2 has its quick and dirty finish, and is 100% ready for launch. However, it won't be today. Cousin Karl and I have some carpentry to do at the fishing cabin. No Menehune spotted here. Nuclear submarines, whales, mermaids and UFOs, yes.

 

[BABAR]

Hope the fishing is as nice as that cabin!

as for drawing outside the lines, I should be much less arrogant. “Model Rocketry” isn’t just a Big tent, IT’S HUGE. Everything from MicroMaxx to a 1/10 scale Saturn V (I am sure that record has been broken since, but I can’t find it at the moment), and from featherweight recovery to Remote Control gliders, scale models detailed down to individual rivets to flying crayon banks and PortaPotties (both table top and life sized!). Of course, all I have for reference is a few rocket building folks and this forum (@kuririn frequently references “Ye Olde Rocketry Forum”, so there is a lot going on that I am unaware of.) in this forum there are many master craftsman who can produce models that look like they came out of a NASA laboratory or a Stat Wars movie set, and models that go really really really high on little itsy bitsy tiny motors. Not so many that try to fly the traditionally unflyable, or build things that won’t go into a sim program. You read the books, “It is still possible to get direct staging to work even if the stages are separated by 10 inches.” *. The truth is it’s been done over 50 inches.

no question there IS an envelope beyond which we can’t go. But in many ways we operate within the limits of assumptions that haven’t even approached that envelope.

so it is nice to see someone trying things that, at least recently or reportedly, haven’t been tried. People that challenge the assumptions. I recently reviewed Tim’s book on Model Rocketry (which overall is a great book which I recommend, although I think Stine’s book is better, if a bit outdated) and the sections on Magnus Effect and Horizontal Spin. Tim’s a former NASA engineer, but I think the sections in his book regarding how these systems work have the physics wrong.

Hope to have some flights to report later this morning. May not have pics, I am having a problem transferring files from my phone to my computer. I am convinced I am permanently cursed with electronic invisible gremlins which thwart any attempts I make to use electrical devices of any sort.

I wish you great flights and a catch of tasty fresh fish!

*It is still possible to get direct staging to work even if the stages are separated by 10 inches.
https://www.apogeerockets.com/Tech/How_2-Stage_Rockets_Work

 

[icyclops]

“I've been out of touch with model rocketry for over 30 years. It's surprising to me that "not many are willing to color outside of the lines". But really what are the lines? The code(s)? The stratification of model rocketry into fixed categories? Being a maverick innovator is no guarantee of success, but is great amusement at this time of pandemic. Believe it or not, my next rocket could have 18 fins.”

What.....color outside the lines???? Do you mean no one on this site or model rocketry is doing anything new and innovative.

I really disagree.... That’s an assumption on my part to what you wrote, so if I have assumed wrong I am sorry.

But innovation and invention are two different things....between new and exciting paint jobs, better construction techniques, and some really cool designs I think this hobby is doing pretty well. And putting a bunch of fins on a rocket doesn’t necessarily mean it’s innovative Or new. Using them in such a way which makes it do something different, physically react, or an entirely different shape is.

good luck on your launch.

 

[mooffle]

(to my admittedly limited knowledge,@Dotini and I are the only ones at least in recent years to post on this technique.)

Haha, can I get an honorable mention here for my tumble/spin mini-roc?

 

[mooffle]

I agree that the fulcrum would be the CG. If you want to experiment with different size hole you could try an oblong notch and slide a tube sleeve over (or coupler inside) and adjust between flights until the effect is what you want.

What.....color outside the lines???? Do you mean no one on this site or model rocketry is doing anything new and innovative.

I really disagree.... That’s an assumption on my part to what you wrote, so if I have assumed wrong I am sorry.

There's enough of us to keep it interesting but not enough to get us in trouble. I'm always amazed to see how exact the 'line colorers' can get with attention to detail or how the 'scribblers' come up with crazier stuff than me.
I generally consider myself a scribbler...

 

[Cape Byron]

I agree that the fulcrum would be the CG. If you want to experiment with different size hole you could try an oblong notch and slide a tube sleeve over (or coupler inside) and adjust between flights until the effect is what you want.

That's really clever.

 

[icyclops]

“Not so many that try to fly the traditionally unflyable, or build things that won’t go into a sim program.”

Really, that’s the only thing I like to build....curved fins....rocs so short and stubby how can it fly.....body tubes that split in half and a smaller rocket emerges....at apogee the roc opens up like an umbrella....etc.....I don’t do Sim.

Obviously I do agree it is always great to see others do things out of the ordinary....and why not get in trouble. HAHAHA...
I love to see the new and creative designs both in construction and paint. There are some really great designers on this FORUM.

I guess some of us have been doing this for so long we need to share more images and techniques....so we are not labeled as boring designers only building long skinny 4 fin roc’s...however I am not a show and tell kind of guy....just saying my opinion....results may vary.

enjoy.

 

[Dotini]

Haha, can I get an honorable mention here for my tumble/spin mini-roc?

I'd very much like to see your tumble/spin mini-roc.

Investigating small field recovery systems is by personal necessity the main occupation of my participation in model rocketry. Being from the counterculture generation of the 50/60's, I'm attracted to coloring outside the lines. So when the Holy Grail of the Magnus Effect was offered up by Van Milllgan as out there, and others scoffed and said it couldn't be done with a model rocket, naturally it appealed to me as a Romantically fitting project. This is even though I have alway intuitively avoided long skinny rockets and preferred more shapely ones. This is the way I choose to amuse myself. But all that said, I will reiterate I have made the pledge to abide by the Safety Code.

 

[BABAR]

Haha, can I get an honorable mention here for my tumble/spin mini-roc?

Absolutely! I brain farted in failing to mention your Lepton!
https://www.rocketryforum.com/threads/spin-recovery-concept-and-build-thread.162615/page-2
I’m thinking after looking at the results of your flights and @Dotini and my stuff that yours may have succeeded in GETTING to full horizontal spin had it had more free fall time.

I look forward to further “coloring outside the lines” from your neck of the woods!

 

[Dotini]

Full horizontal spin recovery has been achieved with Magnus X-2 this morning in six consecutive videotaped flights.
The rocket, 3.95 oz on the pad, spun slowly on ascent (B6-2 in all cases), went level at apogee/ejection event, backslid across the wind spinning several times a second. Three times the test was performed with the nosecone ejected, and three times with a two-punch fixed nosecone. The wind was from the north at 4-8 mph. The cone/streamer drifted south and the rocket tended east across the wind, spinning counterclockwise with the tube perpendicular to the wind. All landings were horizontal with no damage except for scuffed paint. Once it landed on the hard packed dirt of the baseball diamond infield, and again, no damage. When the puffer ports were used, there was no violent pinwheeling as before with X-1. Video in a day or two.

Oh, there was zero indication of fin flutter.

 

[mbeels]

Video in a day or two.

Cool! Looking forward to it.

 

[Rktman]

Full horizontal spin recovery has been achieved with Magnus X-2 this morning in six consecutive videotaped flights.
The rocket, 3.95 oz on the pad, spun slowly on ascent (B6-2 in all cases), went level at apogee/ejection event, backslid across the wind spinning several times a second. Three times the test was performed with the nosecone ejected, and three times with a two-punch fixed nosecone. The wind was from the north at 4-8 mph. The cone drifted south and the rocket tended east across the wind, with the tube perpendicular to the wind. All landings were horizontal with no damage except for scuffed paint. Once it landed on the hard packed dirt of the baseball diamond infield, and again, no damage. When the puffer ports were used, there was no violent pinwheeling as before with X-1. Video in a day or two.

Oh, there was zero indication of fin flutter.

Congrats! If it was truly horizontal and Magnus X-2 was moving sideways as it descended, then you may have achieved quite a unique milestone: evidence of Magnus Effect lift using horizontal spin recovery!

 

[BABAR]

Congrats. I had some good flights yesterday, including my remake of Eric’s Back Slider (no spin), and it did fly straight! I look forward to comparing notes. My videos aren’t too great. Hopefully will have time to transfer pics and post some youtubes.

 

[Dotini]

Congrats! If it was truly horizontal and Magnus X-2 was moving sideways as it descended, then you may have achieved quite a unique milestone: evidence of Magnus Effect lift using horizontal spin recovery.

Those emoticons are exhilarating! But I'm making no claims to the Magnus Effect. The videos will tell their own story.


With ejection of cone and streamer
View attachment X-2 #2 streamer.mov








View attachment x-2 #4 puffer1.mov





















With two port puffer.

 

[neil_w]

That's cool, you should submit it to Apogee for POF (unless you have other plans for it).

 

[Bruce]

The videos will tell their own story.

Great flights there! Perfect horizontal recovery in both, even in the wind. Good Job!

 

[mooffle]

I'd very much like to see your tumble/spin mini-roc.

Investigating small field recovery systems is by personal necessity the main occupation of my participation in model rocketry. Being from the counterculture generation of the 50/60's, I'm attracted to coloring outside the lines. So when the Holy Grail of the Magnus Effect was offered up by Van Milllgan as out there, and others scoffed and said it couldn't be done with a model rocket, naturally it appealed to me as a Romantically fitting project. This is even though I have alway intuitively avoided long skinny rockets and preferred more shapely ones. This is the way I choose to amuse myself. But all that said, I will reiterate I have made the pledge to abide by the Safety Code.

I've always been a fan of heavy design constraints. It forces innovation that otherwise wouldn't happen. Besides when everyone says "can't be done" it means someone has to try.

I’m thinking after looking at the results of your flights and @Dotini and my stuff that yours may have succeeded in GETTING to full horizontal spin had it had more free fall time.

When I get ballsy maybe I'll try out an A10 or stage it somehow to get it the height it needs. I should update that thread anyway, my ring struts have needed some repair and I have the pics for it, tumble/spin is not easy on long fins.

 

[BABAR]

I've always been a fan of heavy design constraints. It forces innovation that otherwise wouldn't happen. Besides when everyone says "can't be done" it means someone has to try.

I’m with you. It’s sort of like the sign that says, “Wet Paint.” You just GOTTA touch it and check.....

 

[Dotini]

In reviewing what was achieved with Magnus X-2, I think I can conclude the following:
1) Robust and durable construction with plastic fins and extended motor mount in BT-50 tube enabled repeated tests with confidence in rocket survival.
2) Ejection event with puffer port or nosecone ejection both worked well. The former was more aesthetically pleasing, but the later could prove to be the more reliable method for building evidence of Magnus Effect. This question remains open.
3) Alternating black/white BT-50 sections proved easily visible in establishing spin rate.

Things to test in the immediate future with X-2:
1) Reduced length/diameter ratio, moving in steps down from 50:1 to 30:1.

My estimated path to establishing more/better evidence of the Magnus Effect:
1) Larger tube diameter.
2) Faster rate of spin.
3) A modest increase in altitude at apogee, perhaps another one or two hundred feet.

 

[BABAR]

Question:

what is the relationship of horizontal spin AND Magnus force to wind?

implications:

unfortunately Magnus effect is lateral to falling trajectory and doesn’t significantly slow the rocket. But WIND will definitely cause some lift, the problem is that this “lift” may be UPWARD (helpful in slowing the rocket) or DOWNWARD (not so good) depending on whether the rocket is “backspinnning” or “top spinning” relative to the wind. This depends on the orientation of the rocket and the direction of the wind. These are not obciously not directly in control of the Flyer, UNLESS the same effect that direct the rocket horizontal to the fall vector ALSO responds to the lateral wind vector.

so did your lateral Magnus translation consistently go WITH or AGAINST the wind?

from a Flyer perspective, Magnus force while cool may NOT be a good thing. Especially in small fields, the ideal rocket trajectory is straight up and straight down (the first fast, the second ideally much slower!). If Magnus translation (lateral movement) is random vis a vis the wind, and if it is significant, it kind of becomes a negative as it might take the rocket “out of the park”. If however somehow the physics conspires to orient the Magnus direction INTO the wind, it may be a positive.

note the HORIZONTAL ORIENTATION effect of the spinning rocket is definitely a plus (certainly beats the pants off a ballistic lawn dart!). The Magnus force or effect, at least the way we are generating it, at this point seems to be an entertaining side effect (pun intended), and could be detrimental if either random or occurring on a windless day.

 

[Dotini]

Question:

what is the relationship of horizontal spin AND Magnus force to wind?

implications:

unfortunately Magnus effect is lateral to falling trajectory and doesn’t significantly slow the rocket. But WIND will definitely cause some lift, the problem is that this “lift” may be UPWARD (helpful in slowing the rocket) or DOWNWARD (not so good) depending on whether the rocket is “backspinnning” or “top spinning” relative to the wind. This depends on the orientation of the rocket and the direction of the wind. These are not obciously not directly in control of the Flyer, UNLESS the same effect that direct the rocket horizontal to the fall vector ALSO responds to the lateral wind vector.

so did your lateral Magnus translation consistently go WITH or AGAINST the wind?

from a Flyer perspective, Magnus force while cool may NOT be a good thing. Especially in small fields, the ideal rocket trajectory is straight up and straight down (the first fast, the second ideally much slower!). If Magnus translation (lateral movement) is random vis a vis the wind, and if it is significant, it kind of becomes a negative as it might take the rocket “out of the park”. If however somehow the physics conspires to orient the Magnus direction INTO the wind, it may be a positive.

note the HORIZONTAL ORIENTATION effect of the spinning rocket is definitely a plus (certainly beats the pants off a ballistic lawn dart!). The Magnus force or effect, at least the way we are generating it, at this point seems to be an entertaining side effect (pun intended), and could be detrimental if either random or occurring on a windless day.

All great questions! About the only one I can honestly answer is that my multiple tests have shown that the Magnus X rockets spin in such a way that the lift is up (counterclockwise), and generally go ACROSS the wind, and neither into it directly nor downwind directly.

We simply need to continue experimentation. For my part, I'm feeling much better after my vaccination lethargy, and I'm now putting the finishing touches on a lingering ringtail after a day at my fishing cabin. Then I will build probably two new Magnus X rockets, one on a BT20 and the other on a BT55. Probably both will have plastic canards, and be fitted with both ejecting and side blowing nosecone sections. Both will have removable sections for shorter lengths. As of this day, I have all the parts and engines needed on hand, several of the fins started, and one of the motor mounts completed.

 

[Rktman]

All great questions! About the only one I can honestly answer is that my multiple tests have shown that the Magnus X rockets spin in such a way that the lift is up (counterclockwise), and generally go ACROSS the wind, and neither into it directly nor downwind directly.

We simply need to continue experimentation. For my part, I'm feeling much better after my vaccination lethargy, and I'm now putting the finishing touches on a lingering ringtail after a day at my fishing cabin. Then I will build probably two new Magnus X rockets, one on a BT20 and the other on a BT55. Probably both will have plastic canards, and be fitted with both ejecting and side blowing nosecone sections. Both will have removable sections for shorter lengths. As of this day, I have all the parts and engines needed on hand, several of the fins started, and one of the motor mounts completed.

I feel you're on the right track in terms of an increased spin rate resulting in an increase in Magnus Effect "lift". Observing the Magnus Effect RC aircraft on YouTube, I believe their pilots increase their model's altitude by increasing the spin rate of the aircraft's rotor "wings". You can often hear the increase in pitch as the small electric motors spin up in rpm. The resulting lower air pressure above the spinning drumlike rotors causes the aircraft to climb.

Edit: this model directly uses control of the spin rate of it's drum rotors to control climb/increase in altitude. A lot of the other Magnus Effect model's achieve the same thing by increasing the rpm of the small propeller in front, driving the aircraft through the air faster to increase the airflow over the rotor drums, causing them to spin faster.

 

[BABAR]

All great questions! About the only one I can honestly answer is that my multiple tests have shown that the Magnus X rockets spin in such a way that the lift is up (counterclockwise), and generally go ACROSS the wind, and neither into it directly nor downwind directly.

We simply need to continue experimentation. For my part, I'm feeling much better after my vaccination lethargy, and I'm now putting the finishing touches on a lingering ringtail after a day at my fishing cabin. Then I will build probably two new Magnus X rockets, one on a BT20 and the other on a BT55. Probably both will have plastic canards, and be fitted with both ejecting and side blowing nosecone sections. Both will have removable sections for shorter lengths. As of this day, I have all the parts and engines needed on hand, several of the fins started, and one of the motor mounts completed.

Glad you are on the mend from the vax.

interesting that your rockets Magnus vector is cross wind. I am theeeeeenking that the dominant vector is the fall vector (up/down), rocket turns horizontal to that, then aerodynamic forces cause it it nose INTO the wind, if any. Mine kind of spiraled, but there was almost no wind, and I think my shorter and particularly thinner BT-5 models while good at going horizontal are BAD at generating much Magnus force.

I am struggling to visualize your canards, I look forward to your pics!

I am very much enjoying the collaboration with you and @mooffle and @icyclops and @Rktman and others who have chimed in here.

 

[Dotini]

First pix of Magnus X-3.



Note stiffening splines on slender BT-20 tube. Note 1/16" standoff under launch lug to avoid rod interference with taped section joins.

 

[BABAR]

First pix of Magnus X-3.

View attachment 461525

Note stiffening splines on slender BT-20 tube. Note 1/16" standoff under launch lug to avoid rod interference with taped section joins.

I like!
Is this a two stage?
Is there more than one launch lug?
Are those 3D plastic or cardboard tubes?
Canards are interesting. If this is NOT. A two stage, From an efficiency standpoint, I am wondering whether you would get just as much rotational efficiency with much LESS drag and much MORE stability simply by lengthening the root of the main fins, so enlarging the surface area of the main fins to equate the additional surface area of the canards.

definitely provides its own major cool factor. Kind of has a Picasso Meets Mars Snooper look.