"Spinning Saucer of the Apocalypse" - 36" Saucer with Helicopter Recovery

Do you mean like the one in Captain America? When the guy with the red face gets away from the burning factory? I have always wanted to build one of those.

I have not done or seen a spinning rocket that achieves all lift from spin.

It would need to be very light, have an aggressive angle of attack on the blade(s) to get lift, and have a very long burning motor. Even then flight altitude would likely be in the tens of feet.

The Spinning Saucer of the Apocalypse (flight weight 7.5 lbs, 3 ft diameter, about 1000 rpm peak spin rate) flies upward only as long as the (downward firing) 2x G64 motors are firing, and then promptly starts to drop after the burn. The (horizontal firing/spin) 8x D12 motors definitely spin the saucer up and stabilize it, but appear to contribute little to effective lift. The fan blades on this spinning saucer have a 15 to 20 degree angle of attack. It continues to spin for a few seconds after it lands on the ground.

The Turbine Rocket Saucer (flight weight 2 lbs, 20 inch diameter, about 1500 rpm peak spin rate) is powered by 5x or 6x D11 or D12 motors that are steeply canted, matching the 30 degree angle of attack of the fan blades. Because of the higher spin rate, lighter weight, and more aggressive angle of fan blade attack, it achieves 2 to 3 seconds of continued lift after motor burnout. Spin stops almost immediately when it touches down.

Every monocopter that I have seen has some downward cant to the motor to help with lift.

Because rocket engines produce very high thrust for short periods of time, but are not very fuel efficient, they are far more efficiently used pointed straight down directly fighting gravity.

Rocket motors that spin too fast for too long have a nasty habit of burning through the outside of the motor casing. This happened with every E9 I loaded into the Turbine Rocket Saucer, but never with the D11-P or D12-0 motors.

Other motor technologies (like electric and gas) are far more fuel efficient and longer running, making them a much more efficient match for and propeller/fan driven flights.

I do not believe the heavier SSoA would lift off the rod at all without the lift motors. The lighter TRS might just get off the rod but not much higher if motors were configured only for spin.

Both of my spinning saucers fly to only around 100 ft altitude, even with motors directly providing most of the lift. These are mostly fire and smoke machines that fly a little too. :dark:

Thanks for all the info. I made mine out of corrugated cardboard and base wood.
One has vanes at a very shallow angle of attack, but sanded into an aerofoil, while the other has flat vanes, with roughly a 30 degree angle of attack. I used 2x18mm engines on both. They both spun crazy fast, but did not lift off. I was thinking of trying to use thicker pieces of balsa wood for vanes, sanded into a high lift aerofoil, with a much larger lift surface. If I do, I'll build mounts for lift engines, just in case.

delta22 said:

Rocket motors that spin too fast for too long have a nasty habit of burning through the outside of the motor casing.

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I've found that true with the Art Applewhite Double Helix I have. I also found that where the motors are placed, 1/4" of tape vs. 3/4" of tape for thrust rings makes a big difference also.

My question is the Composite lift motors. They are not very far from the center, but do you see the burning out the side affect on the liners of these when you disassemble them? How are the cases holding up?

G64's (and G76's, like I use in my Giga Drill Breaker) are slot burning to begin with, so they tend to burn through the liners on the slot side no matter whether or not they're spinning. I've never had burn-through on the core-burning, single-grain G138, spinning flight or not.

Plus, note that they don't burn as long as BP motors like the E9 do.

Handeman said:

My question is the Composite lift motors. They are not very far from the center, but do you see the burning out the side affect on the liners of these when you disassemble them? How are the cases holding up?

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I have not seen any burn through of the liners on the G64 motors.

They are very close to the center axis on the big saucer and burn for less than 2 seconds.

My AT RMS 40-120 cases are holding up very well considering that three of them have each been fired about 30 times in the last 6 years.

flight 5: 7/21/12 CMASS Amesbury, MA

Lifted off again on 2x G64 + 8x D12.

Good stable, fast spinning flight.

Is it possible this beast coulg fly on 2xH motors, like the H54 or H90?

This video of flight 5 shows the fast spin continuing for several seconds after touchdown.

Standard flight pattern for this saucer.

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

MasonH said:

Is it possible this beast coulg fly on 2xH motors, like the H54 or H90?

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That is a very interesting question....

I have a few 3grain 29mm Pro-X long burn motors on order, including some H54's.

As the 8x D engines provide lots of spin, a little more lift could be fun.

Will try 2x H54's for lift this spring or summer.

Only downside is these very nice loads are about 2x the price of AT G64 loads.

flight 6: 10/6/12 CMASS / MMMS Berwick, ME

Another good flight on 2x G64 + 8x D11-P

flight 7: 11/17/12 CMASS Amesbury, MA

Used 2x AT G80T engines for lift instead of the usual G64W, resulting in a slightly quicker and higher lift and more definition to the helix of smoke created by the 8x D11-P motors used for spin.

Flight 7 video:

[video=youtube_share;mm-iBroFb1A]https://youtu.be/mm-iBroFb1A[/video]

2012 year-end summary of the Spinning Saucer of the Apocalypse.

This year:

7 flights total, always with 2x 29mm AP motors for lift and 8x 24mm BP motors for spin.

All 70 motors loaded fired, using my cluster box and Rocketflite CF igniters.

5 of 7 flights used 2x AT G64 engines for lift and 8x Estes D engines for spin.

Works well:

Flights are safe and a lot of fun, this being a fire and smoke machine that also flies. Altitudes very modest, about 70 to 100ft.

The smooth and rounded shape of the ring allows the saucer to land well even while spinning fast.

Could be better:

Slightly more aggressive angle of attack on the fan blades might have generated more lift from spin, gaining a few more seconds flight time for a given motor load.

Going forward:

As mentioned a few posts earlier, will try slightly more powerful lift motors for some flights this coming season.

Definitely plan to get in a bunch more flights on this in 2013.

Do you think the structure could handle a G138T?

CarVac said:

Do you think the structure could handle a G138T?

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It might hold together, but the stresses would be risky on its flat draggy form.

I'm leaning more towards longer burn for the lift to minimize structural stress and maximize total lift.

Just amazing..subscribed here and also on youtube!

I was just wondering about the CG / CP issue on this..thing ...from the physics point of view a mix between helicopter and rocket...how do you place AND measure your CP and your CG? Maybe I am too stupid or I need to read more carefully, please point me where I can read about that...

Thx
Denis

Being spin stabilized, CP/CG is largely not relevant on a rocket like this.

This is an AWESOME project!

CarVac said:

Being spin stabilized, CP/CG is largely not relevant on a rocket like this.

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Spin can be important, but on an oddroc with much lower Cd. On a saucer the CP is behind the base of the rocket due to massive drag. On a design like this I'd venture to say it's some of both. For my L2 I was asked how to prove that the rocket was stable, and I showed them these pictures from Art Applewhite. https://artapplewhite.com/cp.html

A generic shaped saucer of x sides will always be stable upon liftoff

If you see how incredibly fast this spins in the video (to the point it is aliasing and looks stationary!), and if you think about the sheer stability of the heavy rim acting as a gyroscope, you work realize that cp has almost nothing to do with anything here.

Giga Drill Breaker spun slower and had a less advantageous inertia tensor but it basically ignored aerodynamics entirely.

That is some fantastic workmanship!

A couple of times it came down pretty close to the pad. Are you worried that it might end up getting speared on the launch rod?

edwinshap1 said:

Spin can be important, but on an oddroc with much lower Cd. On a saucer the CP is behind the base of the rocket due to massive drag. On a design like this I'd venture to say it's some of both. For my L2 I was asked how to prove that the rocket was stable, and I showed them these pictures from Art Applewhite. https://artapplewhite.com/cp.html

A generic shaped saucer of x sides will always be stable upon liftoff

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Yes, spin stabilized throughout the flight, hitting a peak of about 1000rpm at spin motor burnout, and still spinning quickly for seconds after touchdown.

Probably a moderate amount of "saucer edge" air turbulence stabilization during the quickest part of the lift only.

I have the same Applewhite Cp/Cg graphic in my rocketry binder in case anyone asks me about saucer stability.

In response to a question a few years ago, Art Applewhite explained to me by email that the sharp outer edge on his saucers creates the turbulent pocket of air that acts to stabilize his cool saucers.

Derek said:

That is some fantastic workmanship!

A couple of times it came down pretty close to the pad. Are you worried that it might end up getting speared on the launch rod?

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Thanks.

Yes, if this ever comes down onto the launch rod the Spinning Saucer of the Apocalypse may very well be destroyed.

As an HP flier, the 200ft spectator distance will keep people quite safe.

To try to reduce the chances of a "saucer impaled on rod" recovery I:

> Angle rod very slightly downwind to try to assure saucer travels away from rod.

> At LDRS with many launch pads in a row, set up saucer at downwind end of row.