Are Odd'l Rockets Oddrocs? Some considerations modeling the Odd'l Cyclone

[Blast it Tom!]

First off, let me state that my boss's wife gave me a coffee mug that reads, "Hold on. Let me overthink this..." Now @hcmbanjo's "Cylcone" is a real piece of work. He has already advised me to build it light, little or no paint, etc. Well, nutjob that I am, I had wanted to look at the theory and development that Chris had linked to but now even the Wayback machine isn't getting it.

See, I know that a mapleseed recovery is a careful balance of CG, moment of inertia, drag, overall weight, etc. to get you to your correct spin rate. But it's almost against my religion not to airfoil, or at least shape the leading and trailing edges somewhat. Aerodynamics! But if that throws the balance off, or increases the spin rate due to the lower drag and mass moment of inertia... And if I sand the nosecone flush with the tube... but I could make up some lost weight with paint and even reflective mylar strips from some streamer stock (Mylar balloons bought by my brother-in-law for my wife's 65th 39th birthday). And would a thin coat of white followed by some flourescent orange be too much paint? Ah, if I just understood the design parameters and sensitivities!

I thought about building it naked, unsanded fins, etc. and then checking the mass and balance location and working it from there, always attempting to bring it back to the same place. But that doesn't help (unless one takes special pains) with the mass moment of inertia or the effects on drag that set up the spin rate.

Has anyone else built this one? Does anyone have the theory workup in their files anywhere? And how would one adhere reflective mylar to a rocket? Super glue? NO, NO don't turn this into a glue thread!

Thanks all! I'll continue overthinking this!

 

[DES]

Aerosol contact cement, like the 3m spray adhesive. Very light mist should be sufficient for light mylar films, it will turn it into equivalent of sticky tape for a few minutes.

 

[BABAR]

First off, let me state that my boss's wife gave me a coffee mug that reads, "Hold on. Let me overthink this..." Now @hcmbanjo's "Cylcone" is a real piece of work. He has already advised me to build it light, little or no paint, etc. Well, nutjob that I am, I had wanted to look at the theory and development that Chris had linked to but now even the Wayback machine isn't getting it.

See, I know that a mapleseed recovery is a careful balance of CG, moment of inertia, drag, overall weight, etc. to get you to your correct spin rate. But it's almost against my religion not to airfoil, or at least shape the leading and trailing edges somewhat. Aerodynamics! But if that throws the balance off, or increases the spin rate due to the lower drag and mass moment of inertia... And if I sand the nosecone flush with the tube... but I could make up some lost weight with paint and even reflective mylar strips from some streamer stock (Mylar balloons bought by my brother-in-law for my wife's 65th 39th birthday). And would a thin coat of white followed by some flourescent orange be too much paint? Ah, if I just understood the design parameters and sensitivities!

I thought about building it naked, unsanded fins, etc. and then checking the mass and balance location and working it from there, always attempting to bring it back to the same place. But that doesn't help (unless one takes special pains) with the mass moment of inertia or the effects on drag that set up the spin rate.

Has anyone else built this one? Does anyone have the theory workup in their files anywhere? And how would one adhere reflective mylar to a rocket? Super glue? NO, NO don't turn this into a glue thread!

Thanks all! I'll continue overthinking this!

Be careful flying it nekkid. Depending on your field, balsa and cardboard parts with no chute or streamer can be very hard to find. I lost half of a Flutter Bye this way. It was fall. Grass brown. Lots of balsa colored leaves. You get the picture.

 

[hcmbanjo]

First off, let me state that my boss's wife gave me a coffee mug that reads, "Hold on. Let me overthink this..." Now @hcmbanjo's "Cylcone" is a real piece of work. He has already advised me to build it light, little or no paint, etc. Well, nutjob that I am, I had wanted to look at the theory and development that Chris had linked to but now even the Wayback machine isn't getting it.

See, I know that a mapleseed recovery is a careful balance of CG, moment of inertia, drag, overall weight, etc. to get you to your correct spin rate. But it's almost against my religion not to airfoil, or at least shape the leading and trailing edges somewhat. Aerodynamics! But if that throws the balance off, or increases the spin rate due to the lower drag and mass moment of inertia... And if I sand the nosecone flush with the tube... but I could make up some lost weight with paint and even reflective mylar strips from some streamer stock (Mylar balloons bought by my brother-in-law for my wife's 65th 39th birthday). And would a thin coat of white followed by some flourescent orange be too much paint? Ah, if I just understood the design parameters and sensitivities!

I thought about building it naked, unsanded fins, etc. and then checking the mass and balance location and working it from there, always attempting to bring it back to the same place. But that doesn't help (unless one takes special pains) with the mass moment of inertia or the effects on drag that set up the spin rate.

Has anyone else built this one? Does anyone have the theory workup in their files anywhere? And how would one adhere reflective mylar to a rocket? Super glue? NO, NO don't turn this into a glue thread!

Thanks all! I'll continue overthinking this!

You are probably overthinking it!
I have flown many Cyclone models, with and without paint.
Painted Cyclone models won't get you the Mapleseed "hover". Unpainted Cyclones will give a long spinning recovery.
No need to airfoil the fins, heck they are only 1/16" thick as is. An Airfoil will weaken the long fin span. They could shred under boost.
The only thing I might recommend is running a line of glue down the rounded leading edges to slightly stiffen them up.
Most Mylar (trim Monokote) is already adhesive backed. Some chrome trim should be fine and not effect performance much.

On the first flight - Use a 1/2A motor. Be prepared to be very surprised how well it spins.
Listen close for a whistle -
Save the A3 motor for a larger field. Good luck!

 

[Blast it Tom!]

You are probably overthinking it!
I have flown many Cyclone models, with and without paint.
Painted Cyclone models won't get you the Mapleseed "hover". Unpainted Cyclones will give a long spinning recovery.
No need to airfoil the fins, heck they are only 1/16" thick as is. An Airfoil will weaken the long fin span. They could shred under boost.
The only thing I might recommend is running a line of glue down the rounded leading edges to slightly stiffen them up.
Most Mylar (trim Monokote) is already adhesive backed. Some chrome trim should be fine and not effect performance much.

On the first flight - Use a 1/2A motor. Be prepared to be very surprised how well it spins.
Listen close for a whistle -
Save the A3 motor for a larger field. Good luck!

Thanks, Chris. I didn't want to bug you exclusively but I do value your (further) input. I am definitely an overthinker. You see, there a two reasons why I think the way I do:
1. I'm very inclined toward analytical modeling. I like to calculate the numbers and see them work out in real life. So balancing all the factors I listed sounded like a fascinating prospect.
2. I can't build a bunch of them and finish them in all different manners to see what affects what via test.

My mylar is not adhesive-backed - it's actually deflated helium ballons that my brother-in-law bought for my wife's birthday. I thought something shiny on something spinning might make reflective flashes that would make it easy to follow.
But I can't help but wonder. Is it the extra mass/inertia of the paint that prevents the hover, even though the finish could be glass-smooth and (presumably) reduce drag? I mean, that certainly is a very light model, it wouldn't take much CWF/paint to mess with the balance, the mass, and the mass moment of inertia (affects spinning). Obiously I'll minimize the paint... CA the leading edge of the fin - stuff like that. And then see how it goes. As I've said, I like showing the grandkids different ways to do things. They love the Birdie, and I should note that Pigasus had a successful return to flight after the tube crumpling accident last winter (cold plastic parachute...)

 

[neil_w]

I love this little rocket.

I hand-painted a few bits of it, enough for some decor but far less weight than a full paint job.

It really gets spinning and comes down slowly. I echo Chris's recommendation to fly with a 1/2A. I've already come close to losing it a couple of times on the 1/2A, don't think it's worth risking a full A. Flights on the 1/2A are *very* satisfying.

No way in hell would I even think of airfoiling those fins; they're delicate enough as it is. If you want to round the edges... well OK, if you must, I guess it can't hurt, but I don't see the point (and I normally round every fin on every rocket).

Build it, fly it, enjoy it. It's actually a fun little build, I've built two so far and wouldn't mind building another if I actually had any reason to do so.

 

[Blast it Tom!]

Mighty pretty, Neil!

 

[hcmbanjo]

My mylar is not adhesive-backed - it's actually deflated helium ballons that my brother-in-law bought for my wife's birthday. I thought something shiny on something spinning might make reflective flashes that would make it easy to follow.
But I can't help but wonder. Is it the extra mass/inertia of the paint that prevents the hover, even though the finish could be glass-smooth and (presumably) reduce drag? I mean, that certainly is a very light model, it wouldn't take much CWF/paint to mess with the balance, the mass, and the mass moment of inertia (affects spinning). Obiously I'll minimize the paint... CA the leading edge of the fin - stuff like that. And then see how it goes.

A thin Mylar band might be fine, adhere it with some spray adhesive. I've launched both "near bare" models and one painted like the face card from the kit.
The heavier painted version did spin (some) but no where near the performance of the near naked version.
Think of it like a boost glider - paint it and the glide will be poor. Color it a bit with permanent markers and watch it spin.

 

[Blast it Tom!]

A thin Mylar band might be fine, adhere it with some spray adhesive. I've launched both "near bare" models and one painted like the face card from the kit.
The heavier painted version did spin (some) but no where near the performance of the near naked version.
Think of it like a boost glider - paint it and the glide will be poor. Color it a bit with permanent markers and watch it spin.

Thank you sir... I should note that I've never flown a boost-glider - that's still on the list of "to-do's". But I must also note that I flew it nekkerd as you advised (also on the 1/2A as you'd advised..." and indeed got beautiful spin and hang time off of it. The helicopter action on the booster portion was good as well. The fins were carefully sanded smooth and rounded on both sections, and I'd carefully sanded the nosecone flush with the body tube, then filled it with CWF and sanded it "baby's backside" smooth. I figured I could afford the fill because I took enough off the nosecone.

And cold weather is upon us. Time to consider my options for further finishing. If I have the guts - why ruin a good thing? Besides' I still have your "Breakaway" and Jim Flis's ACME Spitfire to construct. But I still ponder... how much does a finish weigh? How would it affect the CG, the mass moment of inertia? I can't help it, I'm a numbers guy, a design engineer.

 

[kuririn]

I flew mine nekkid recently.
The rocket, not me.
It flew well. Too well, as it turns out.
The bottom half was recovered but the top half landed on a roof at the community college where we sometimes launch.
The rotation is beautiful to watch.
Too bad I neglected to take scans of the fins. Replacement arrived this past Saturday.
BTW it was a 1/2A motor.

 

[Blast it Tom!]

Too bad, my friend. I've seen some vidoes of you guys at that site but can't really estimate its size well. I'm feeling fortunate. Here in hilly, tree-covered Western PA I've happened on a site with 4800' clear east to west (our most prevalent wind direction) and at least 6000' N-S. I have <ahem> high hopes for this - but not too high, as I have flown over it many times on approach to Pittsburgh International. But at least going up a couple thousand feet shouldn't be a problem, as long as we can get permission. It's an industrial site (a no longer needed drainage lake being drained), still owned by a utility, and I know some environmental remediation is going on. But if I can, I'm going to see if the local clubs would help me out with whatever we need to do. Resouces like this don't come along very often around here! Like, never in my life!