Horizontal Spin Recovery - with Magnus Effect?

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
We had a superb morning launch session today at 60 Acres. Clear skies and 3-5 mph winds prevailed throughout the session. First we launched an Estes scale Patriot on a C5-3 (394'), then two members of the Prontosaurus family with the 55/E12-6 attaining 1,692', and finally two Magnus effect models.

The repaired Magnus X-6/C11-3 once again took off for the next county, gliding 663' straight south with a disappointing descent time of only about 20 seconds.

The new Magnus X-7 was launched on three motors, B4-4, B6-4 and C6-5. All good, but the latter flight was most interesting! After just barely beginning to go ballistic after apogee, the ejection event commenced an immediate rapid horizontal spin. A new record 45+ seconds were consumed as the model then slowly spiraled down to within 200' of the launch pad!! This is what it's all about, my friends.

After I get rested up and organized, more data, photos and video are to come.
 
We had a superb morning launch session today at 60 Acres. Clear skies and 3-5 mph winds prevailed throughout the session. First we launched an Estes scale Patriot on a C5-3 (394'), then two members of the Prontosaurus family with the 55/E12-6 attaining 1,692', and finally two Magnus effect models.

The repaired Magnus X-6/C11-3 once again took off for the next county, gliding 663' straight south with a disappointing descent time of only about 20 seconds.

The new Magnus X-7 was launched on three motors, B4-4, B6-4 and C6-5. All good, but the latter flight was most interesting! After just barely beginning to go ballistic after apogee, the ejection event commenced an immediate rapid horizontal spin. A new record 45+ seconds were consumed as the model then slowly spiraled down to within 200' of the launch pad!! This is what it's all about, my friends.

After I get rested up and organized, more data, photos and video are to come.

45 seconds... :shocked:

Congratulations... you've certainly earned it.
 
We had a superb morning launch session today at 60 Acres. Clear skies and 3-5 mph winds prevailed throughout the session.
With your side ports to get the effect started, have you tried to add a hood or something to direct the gases to “kickstart” the spin by blowing the gases out of the side and encouraging the spin...??? Just spitballing here...
 
With your side ports to get the effect started, have you tried to add a hood or something to direct the gases to “kickstart” the spin by blowing the gases out of the side and encouraging the spin...??? Just spitballing here...

Dual exhaust headers... on a rocket. Sweet.
 
With your side ports to get the effect started, have you tried to add a hood or something to direct the gases to “kickstart” the spin by blowing the gases out of the side and encouraging the spin...??? Just spitballing here...
Last year we experimented briefly with such a concept. It worked! However, we were at such an early stage in the overall program that we set the advanced concept aside for the moment and haven't gotten back to it yet. We encourage further experimentation.

Edit: the X-7 rocket began strongly spinning at the moment of launch solely by virtue of the folded fins.
DSC00624.jpg
Early experiment with utilizing multiple exhaust ports to initiate spin on a BT-50 model.
 
Last edited:
I've begun my latest in the Magnus X series. It will be BT-50 packing a D12-5 or D12-7 motor, painted black and fluorescent pink for visibility. Design improvements include increasing its tendency to spiral rather than glide in a fixed direction. The goal is a 1000' apogee with a 1 minute descent landing within 250' of the pad.

DSC00626.jpg
Fins manufactured from raw stock in ~15 minutes ready to install and finish. Fins are 1.5" x 2" x 0.020", weighing 0.20 oz. per set of 4. Material is PETG cut from commercial 3" thin wall shipping tube.
 
I've begun my latest in the Magnus X series. It will be BT-50 packing a D12-5 or D12-7 motor, painted black and fluorescent pink for visibility. Design improvements include increasing its tendency to spiral rather than glide in a fixed direction. The goal is a 1000' apogee with a 1 minute descent landing within 250' of the pad.

View attachment 513663
Fins manufactured from raw stock in ~15 minutes ready to install and finish. Fins are 1.5" x 2" x 0.020", weighing 0.20 oz. per set of 4. Material is PETG cut from commercial 3" thin wall shipping tube.
Nice. You may find a durability advantage with these. The rocket will still come in spinning with a ton of rotational kinetic energy that has to go somewhere, but the curves and flexibility and the DIRECTION of rotation may allow this to dissipate much less jarringly than your fixed angled fins, in fact it may actually bounce!

looking forward to build and flight, as always.
 
We have a some developing news to report in the little world of HSR - Horizontal Spin Recovery.

1) The collaborator of my little team, another retired Boeing engineer, is building a novel HSR rocket with an interchangeable fin can, separable from the main body tube and motor mount. This will enable rapid experimentation with a variety of fin sizes, shapes and configurations.

2) Even more exciting, we are teaming up with another small team of retired Boeing engineers who fly a substantial fleet of RC aircraft and drones. We plan on aerial photography sessions at 60 Acres to video and study at close range the full flight and particularly the blow-over events of HSR rockets.
 
You know it’s a long rocket when you need TWO stands to display it!
Well, you know me, mister belt-and-suspenders has a habit of being cautious!
Actually, this model is the most rigid, straight and strong 50:1 design I've made yet. I've replaced the usual Apogee coupler to join the two Apogee tubes. Instead, I've used the Rocketarium coupler. It is much stiffer and of slightly higher diameter, making for a very nice tight fit. I also use a second such coupler directly in front of the motor in lieu of a motor block ring, as it greatly enhances the strength of the tube directly in front of the motor, the "crumple zone".
DSC00651.jpg
 
Finally beautiful weather has arrived (winds 1 mph)! A trip to 60 Acres this morning yielded 3 great launches before the field began filling up for soccer practice. Flight #2 on a C6-5 resulted in a descent time of about 42 seconds. Much more experimentation needs to be done with this particular model since it was designed and built to utilize interchange fins and tubes. My launch partner, like me a retired Being engineer, built this model himself, his first scratch built, at my shop. Testing resumes next week. We have 3 fin cans and 4 body tube lengths to experiment with.

DSC00654.jpg
Magnus Opum Mk 1.2

Edit: A group of spectators clustered around us after our first launch on a B4-2. They were totally astonished at how a rocket could descend so slowly and land like a feather without a parachute. After our rocket launched on the C6-5, they gasped and shouted expletives at the amazing altitude, tracking smoke and loud pop at apogee. The descent seemed to take an eternity, completely horizontal and spinning furiously. It the wind had been up we might have been in trouble, even at 60 Acres.
 
Last edited:
First, congrats on continuing successful designs

Second, I am guessing the newer designs are handling recovery (impact) better? Is this the case?
 
First, congrats on continuing successful designs

Second, I am guessing the newer designs are handling recovery (impact) better? Is this the case?
Absolutely correct. The useful lifetime of an HSR rocket seems to be limited by fin breakage. The newest design returns to flexible PETG fins made from 3" thin wall shipping tube. On the 2nd flight it landed in the middle of an asphalt road and was driven over by a truck. Fortunately, it was between the tires and there was no damage to the fins, tube or cone. And neither did the fins break off, since the trouble was taken to use original Gorilla glue fillets. These are massively strong, albeit exhibit some minor foaming or bubbling effect no matter how carefully the glue is applied.

Experiments resume this week. We will thoroughly test alternate fin configurations and varying tube lengths.
 
Absolutely correct. The useful lifetime of an HSR rocket seems to be limited by fin breakage. The newest design returns to flexible PETG fins made from 3" thin wall shipping tube. On the 2nd flight it landed in the middle of an asphalt road and was driven over by a truck. Fortunately, it was between the tires and there was no damage to the fins, tube or cone. And neither did the fins break off, since the trouble was taken to use original Gorilla glue fillets. These are massively strong, albeit exhibit some minor foaming or bubbling effect no matter how carefully the glue is applied.

Experiments resume this week. We will thoroughly test alternate fin configurations and varying tube lengths.
I was Expecting those plastic tubes would be the perfect ticket! Sounds like time to submit this one to Apogee!
with the price of balsa going up, this may make a very economical kit.

landing on asphalt with no damage is an accomplishment even with a chute, so you have a design that is unique and flies and recovers as well or BETTER than standard. That earns some nice bragging rights!
 
I was Expecting those plastic tubes would be the perfect ticket! Sounds like time to submit this one to Apogee!
with the price of balsa going up, this may make a very economical kit.

landing on asphalt with no damage is an accomplishment even with a chute, so you have a design that is unique and flies and recovers as well or BETTER than standard. That earns some nice bragging rights!
Praise is greatly appreciated, no kidding! :) But before we get the right to brag, we need to verify our results with numerous additional flights testing all our planned permutations.

Interestingly, the design is so unusual that it could create its own NAR competition category.
One of the great unanswered questions of our flights is why some models tend to spiral tightly down to near the launch pad, and why some models want to fly directly south toward the next next county. With C class motors some of our rockets could easily get lost on the first flight, even at 60 Acres. Flying HSR is going to be a proper adventure for anyone and everyone involved. Other mysteries involve why the blowover event differs so much between flights. Also, we are encountering a peculiar "porpoising" effect with the current design - the rocket seems to rock slightly up and down instead of a dead level descent. We think tests with varying tube length could shed light on this question.
 
One of the great unanswered questions of our flights is why some models tend to spiral tightly down to near the launch pad, and why some models want to fly directly south toward the next next county.
Interesting, I have had something of this issue with Back Sliders, although the most common seems to be (unfortunately) a straight glide.

Most of my HSRs had a tight spiral, which was nice. I got away with much shorter rockets, HSR seems less dependent on length than Back Slide. I would however imaging that HANG time is very dependent on length, since I suspect this is the major component of drag on descent. You could make the fins bigger, but I think that would increase weather cocking. I DID find one way around this (I think), and that was to use smaller diameter 1/2 circle fins, you could use more of them, but because they didn't "stick out" so far, they are kind of like tube fins in that they are less prone to weathercocking.

Are your plastic tubes available in different sizes?
 

Interesting, I have had something of this issue with Back Sliders, although the most common seems to be (unfortunately) a straight glide.

Most of my HSRs had a tight spiral, which was nice. I got away with much shorter rockets, HSR seems less dependent on length than Back Slide. I would however imaging that HANG time is very dependent on length, since I suspect this is the major component of drag on descent. You could make the fins bigger, but I think that would increase weather cocking. I DID find one way around this (I think), and that was to use smaller diameter 1/2 circle fins, you could use more of them, but because they didn't "stick out" so far, they are kind of like tube fins in that they are less prone to weathercocking.

Are your plastic tubes available in different sizes?

Thanks for the insights - very interesting.


Last year I purchased plastic tube from Amazon in two sizes, 3" and 2". The size I use most is this:

Ultra-Thin Wall Round Tubes - Clear 3" Round Ultra Thin Wall x 48" Tube PETG MOCAP PRT00107 (qty3)

I paid $42 including tax and shipping.
A set of fins can be easily cut ready to install in mere minutes. They can be painted or Sharpied, but currently ours are unpainted but lightly abraded.

An excellent tool to use for cutting this material is good quality scissors.
DSC00659.jpg

Fiskars, stainless, Finland
 
for budget and small field concerns, smaller tubes may be interesting.

https://smile.amazon.com/Diameter-U...74TKDNZ/ref=dp_fod_1?pd_rd_i=B0874TKDNZ&psc=1
Disadvantages may be that

they are proportionately heavier relative to surface area

they don’t stick out as far into the air stream

You need more for the same size base body tube

Advantages may be

Shorter diameter means less “leverage” on impact so less breakage

Shorter diameter means less fin flutter

Likely less weather cocking

Looks like sizes here would come pretty close to fitting six 1 inch tubes on a BT-50 and six 1/2 tubes on a BT-5. With you scissors technique, would be easy to mount fins whole (complete tubes) the cut away the excess when dry.

It worked well with my cardboard tubes, although they held up okay they got bent after a few flights. Looks like I need to order some stuff from Amazon. Again, with price of balsa this looks pretty reasonable.

How many sets of fins can you get out of three 48” mailer tubes?

Any fin shaping effects? I am guessing that straight cylindrical (maybe curve the tips just so they don’t poke you with sharp edges) is best, but I don’t know.
 
How many sets of fins can you get out of three 48” mailer tubes?

Any fin shaping effects? I am guessing that straight cylindrical (maybe curve the tips just so they don’t poke you with sharp edges) is best, but I don’t know.
I'm going to get approximately 57 sets of 4 fins - or 76 sets of 3 fins - from my three 48" PETG tubes.

So far, most of our fins are square or rectangular and have either slightly or heavily radiused corners.

Note: We had 4 great hours of continuously successful HSR launches at 60 Acres this morning under ideal conditions. New records were set and new discoveries were made. Details to follow by tomorrow!
 
So less than $1 per set, and you are paying retail.

Tim Van Milligan might be able to sell these, now that you have ironed out most of the bugs.

What’s the minimum length to diameter ratio you are consistently successful with? My far more limited experience suggested that the extreme ratios required for backsliders weren’t needed for HSR.
 
Back
Top