The Governator's Frisbee

I got kinda bored on Friday night, so I drew this up - it actually ended up taking me about 1.5 days to do.

If Arnold Schwarzenegger played Frisbee, this is what I imagine he'd play it with. It's a 800mm diameter, carries 12x D or E black powder motors to spin it up, and can take up to 6x 38mm main boosters.



I've designed the whole thing to be milled out of 70mm thick polystyrene sheet. I broke it up into chunks so it will be less effort to make jigs to hold the parts for double sided work, I've also designed it to be fully millable using a 10mm ball nose end mill, because I'm lazy and cant be bothered switching tools. The plywood parts are millable with a 3mm endmill, and the plastic is 3d printed (I'll likely actually print 1 at super high res then make a silicone mould for making the rest out of urethane).

I ended up with 6 motor mounts, because I couldnt decide between two or 3. They are also 38mm because I couldnt decide between 24 and 29mm motors. This may seem illogical, but when you think about it, "the more the merrier" and "bigger is better" riiiiiggght? Actually, with 6 places, I can launch with 2, 3, 4 or 6 motors mounted and retain symmetry. Likewise, with a 38mm grain, it doesnt really cost very much more than a 29mm load however is shorter. The motor mount tubes in this are 200mm long, a 4 or 5 grain CTI 29mm isnt much longer than a 2 grain 38mm and has similar amounts of propellant, sooo why not go the larger motor mount and allow it to be adapted down. At this point, i'm thinking I'll try to fly this exclusively on sparky motors, and only on CTI - the black powder/pyrodex grain in them gets them going so much more reliably than the aerotechs do. This is my first clustered rocket btw, with 18 motors!

I'm using black powder for the rotational motors, as they will come up faster than the central composites which will begin spin stabilisation before the rocket starts moving upwards. I mounted them on top because I think it looks cooler. This frisbee has been designed for aesthetics as I see them, rather than for performance... this style of rocket wont really have much performance but will look cool! I have a feeling that there are too many rotational motors, without any drag consideration i'm looking at about 15,000rpm - so I guess i'll get more like 2000-5000rpm with all motors firing - this is likely to be too high.

I'm planning to use a 1" pvc pipe as the launch rail/rod, with the bushing for it being made out of fibreglass using the pipe as a mandrel. I have 3 pockets on the hub which have doors on them so I can hold batteries for lighting, or avionics for staging. This would allow me to stage the rim motors and/or the main motors. I'm tempted to make the second set of rim motors fire at apogee to spin it up faster.

For a launch system, I'll likely need to use a large relay and a decent sized LiPo battery at the pad, as our launch system uses power cords and a car battery at the LCO's desk to provide power. The power requirements of this will be considerable.

The vanes on the fan are NACA N6409 9% airfoils, simply because I thought it looked good for a fan blade *shrug*.

I'm not planning to start work on this yet, I have a few too many other projects going on which I'd like to get finished, however I would like to launch this on June 1 so I don't have too long before I need to start milling test pieces to check the feasibility.



Thoughts, ideas and questions are always welcome

You need to do a search. Someone has built and flown something very similar. I just don't have a memory anymore.

Handeman said:

You need to do a search. Someone has built and flown something very similar. I just don't have a memory anymore.

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Spinning Saucer of the Apocalypse

https://www.rocketryforum.com/showt...-quot-36-quot-Saucer-with-Helicopter-Recovery

Handeman said:

You need to do a search. Someone has built and flown something very similar. I just don't have a memory anymore.

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Are you serious?! Out of all the responses one expects to a thread for a new rocket someone is building, being told you should search before posting something similar is not something you expect. Yes, I do remember seeing that rocket 2 years ago, yes I know someone else has done a similar style rocket before. Do you go into *every* thread on this forum and saying "You need to do a search, you have 3/4/6 fins, a nosecone and a body tube between them - someone has built and flown something very similar"?

Great concept. Subscribed! op:

That is a really cool design!

Issus said:

Are you serious?! Out of all the responses one expects to a thread for a new rocket someone is building, being told you should search before posting something similar is not something you expect. Yes, I do remember seeing that rocket 2 years ago, yes I know someone else has done a similar style rocket before. Do you go into *every* thread on this forum and saying "You need to do a search, you have 3/4/6 fins, a nosecone and a body tube between them - someone has built and flown something very similar"?

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Perhaps they were just trying to help you out? Boris had some issues with a very similar build, and seeing how he overcame them would certainly help you on your's. Either way, I am really excited to see it!

Issus said:

Are you serious?! Out of all the responses one expects to a thread for a new rocket someone is building, being told you should search before posting something similar is not something you expect. Yes, I do remember seeing that rocket 2 years ago, yes I know someone else has done a similar style rocket before. Do you go into *every* thread on this forum and saying "You need to do a search, you have 3/4/6 fins, a nosecone and a body tube between them - someone has built and flown something very similar"?

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Yeah, while I agree that the post was easy to interpret that way, I suspect he was typing on a phone and kept it brief, while meaning to say that there was a similar build you could learn from. Very cool design and I can't wait to see the rest of the thread.

If it spins and flys -> Boris is the pro.

Would be really cool to use a timer and start the spin motors after the centrals heft it into the air.

wfcook said:

Yeah, while I agree that the post was easy to interpret that way, I suspect he was typing on a phone and kept it brief, while meaning to say that there was a similar build you could learn from. Very cool design and I can't wait to see the rest of the thread.

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+1
Poster tells you 2 things.
It has been done before. Therefore if the ONLY reason you are doing this is to see if it CAN be done you can get the answer with a lot less work.
Also again it has been done before and by reviewing the previous build you may pick up on a lot of tips and pitfalls that could save YOU a lot of time and money and frustration.
You ought to thank that poster.

H_Rocket said:

If it spins and flys -> Boris is the pro.

Would be really cool to use a timer and start the spin motors after the centrals heft it into the air.

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I was thinking the opposite. With the fan blades in the center it could be a cool, slow liftoff on just the spin motors, quite stable in flight, and then a delayed WHOOSH as the centrals light up.

Issus said:

Are you serious?! Out of all the responses one expects to a thread for a new rocket someone is building, being told you should search before posting something similar is not something you expect. Yes, I do remember seeing that rocket 2 years ago, yes I know someone else has done a similar style rocket before. Do you go into *every* thread on this forum and saying "You need to do a search, you have 3/4/6 fins, a nosecone and a body tube between them - someone has built and flown something very similar"?

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I know right!!! You never claimed that it was the "First of its Kind" or anything like that.
Some People here are just quick to jump on others for anything. These same People are the ones that when you answer someones Question, they post a few Posts later with the same answer you already said, then act as if they are the Saviour, even though you already answered the Question.

wfcook said:

I was thinking the opposite. With the fan blades in the center it could be a cool, slow liftoff on just the spin motors, quite stable in flight, and then a delayed WHOOSH as the centrals light up.

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Either way.

Load the center with Warp9 or VMAX -- Nice slow helicopter takeoff then the darn thing teleports.

I remember a flight at Freedom launch 2013 where they rocket was basically the top part of a helicopter, with 1 E9 in each rotor at the very tip. That was a cool flight... Hoping this will do something similar...


BTW, I LOVE the Vmax idea...
Load that sucker up with 3 I49's and 3 I1299's... That would be freaking awesome...

H_Rocket said:

Either way.

Load the center with Warp9 or VMAX -- Nice slow helicopter takeoff then the darn thing disintegrates.

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Fixed that for ya, Al

N

6 I1299's in that thing would do the trick...

Don't use PVC for a launch guide. You have way too much crazy going on to be skimping on guidance. Use a steel or aluminum guide of reasonable stiffness.

I don't have a lot of experience with saucers, but I get the feeling this is going to end up too heavy to not have a parachute. 10lbs+ estimated with three I motor casings?

H_Rocket said:

Either way.

Load the center with Warp9 or VMAX -- Nice slow helicopter takeoff then the darn thing teleports.

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+1 wow

Would it be wrong to add a bunch of swords to this thing?

Not at all, why would you ask?

That is a very cool design. Great work on the 3D imagery too!

I have seen burn through of the motor case just above the nozzle clay on spinning black powder motors. You may get some of this depending on the RPM of the saucer and the burn time of the motor.

It looks like you can use a 1" diameter guide rod...probably a good idea with a cluster of 38mm lifting motors.

Good luck with the build and please post video of the flight.

AWESOME concept. cant wait to see it fly!


My suggestion. EVERY spinning saucer I have ever seen fly does the same thing once motor burns out while its still spinning the rocket will go off on a vector.. like a frisbee. then turn on its side and auger in..

heres a SMALL example.. this one is not too bad but it was the first I found. not sure whos rocket it is but kudos to them!
https://www.youtube.com/watch?v=bNYRVhJXAk0

you need to figure out a way once the motors burn out to slow it down then get out some sort of recovery device..

NO idea how to do it right.. but some brainstorming and it can be done! maybe some air brakes to stop the spin.. (when the e motors eject.. spring loaded Fins pop up) something like that!

good luck... subscribed!

ThirstyBarbarian said:

Would it be wrong to add a bunch of swords to this thing?

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Adding swords to rockets could only be done by Indians trying to scare the British. Ben Hur chariot wheels are not allowed. Vegematic "It slices, it dices, it makes Julian Fries” is also extremely unsafe. To even think of such a thing is at best Barbaric.

wfcook said:

Yeah, while I agree that the post was easy to interpret that way, I suspect he was typing on a phone and kept it brief, while meaning to say that there was a similar build you could learn from. Very cool design and I can't wait to see the rest of the thread.

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I apologise if I did interpret the post wrong, however on pretty much every forum I do frequent if you start a thread and have someone tell you to do a search it would typically mean that it has been done/answered before, please stop wasting out time by posting this crap. Personally, I think everyone's going to build a rocket differently or have some different ideas on how to do things - just look at the huge number of DX3's that get built for a L1 cert - these threads are awesome. So many beginners to high power doing things differently, some with some fantastic ideas of solving the same problems we all have had to at some point, if it was one big "Mad Cow DX3 Projects" thread where everyone had to post there builds in there, it wouldn't give us nearly so many creative, unique builds or as much advice for beginners from experienced members.

wfcook said:

I was thinking the opposite. With the fan blades in the center it could be a cool, slow liftoff on just the spin motors, quite stable in flight, and then a delayed WHOOSH as the centrals light up.

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I have a feeling I'm going to need more RPMs to make this fly on the spin motors, more like 20-30k rpm, however that would have the blades going supersonic which could cause issues (read: destruction.)

H_Rocket said:

Either way.

Load the center with Warp9 or VMAX -- Nice slow helicopter takeoff then the darn thing teleports.

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I must admit, I laughed pretty loud when i read this.

blackbrandt said:

6 I1299's in that thing would do the trick...

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I was planning on glassing this thing, but to take 6x I1299's... wow, I think i'd need a few layers of carbon and a couple of kevlar to withstand that- holy crap. The motors would have 50mm of stickout on the top of the saucer, but you know what - i'd be fine with that! That would be quite the movie-esque ufo takeoff. The force on the outer ring though would be phenomenal, it would have to basically be able to support the front wheel of a car sitting on the hub, with the rim supported on blocks, I'm not even sure how I'd build it that strong... the frontal area on that rim is huge and not capable of handling transonic. That being said, I do love a good ambitious project, I think we have a plan for version 2 of this saucer!

Landru said:

Don't use PVC for a launch guide. You have way too much crazy going on to be skimping on guidance. Use a steel or aluminum guide of reasonable stiffness.

I don't have a lot of experience with saucers, but I get the feeling this is going to end up too heavy to not have a parachute. 10lbs+ estimated with three I motor casings?

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PVC should be stiff enough as a 1M rod, if it's well balanced it shouldnt really be putting much load on the rod. That being said, I do see your point and 1" hardware-store-grade (6065-T0?) aluminium is not expensive stuff. The aluminium will also not get as fowled/destroyed by the composites being right next to it either - something I had not considered until now. I have a feeling that with the RPM this would be doing, it would fly fairly well on even 1 motor - however have no data to back that up.

I'm hoping the fan will provide a small amount of thrust or at least a ton of drag to offset the weight of the saucer. The airframe is around 1kg with just the foam, plywood and plastic according to solidworks, so lets call it 1.2kg with glass and some paint. This makes it 1.7kg with lift motors (yes, half a kilo/1lb of black powder motors). A 2 grain CTI H123 SK is 155g spent, 297g loaded so thats a further 891 grams, this makes it 2.6kg or 5.73202lbs. Not exactly a weight I'd want to fall on my head, so i think the first launch of this will have to be a long way off, at the away pads or something, to protect any spectators (our launches are very small.)

ThirstyBarbarian said:

Would it be wrong to add a bunch of swords to this thing?

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This seems to come up a lot lol. The 3 people I have shown the solidworks files to in person have said:
* How hard would it be to attach razor blades to it (electrical engineer)
* That thing needs something like mower blades on hinges that will snap out when it spins up (mech engineer)
* You should make that a Boadicea (british queen, had knives on the wheels of her chariot) (english born software engineer)

So basically, the main disciplines of engineering completely agree with your stance. This thing needs sharp stuff attached to it. This will not be happening sadly, as I dont think i could slip it past the RSO.

Threemorewishes said:

That is a very cool design. Great work on the 3D imagery too!

I have seen burn through of the motor case just above the nozzle clay on spinning black powder motors. You may get some of this depending on the RPM of the saucer and the burn time of the motor.

It looks like you can use a 1" diameter guide rod...probably a good idea with a cluster of 38mm lifting motors.

Good luck with the build and please post video of the flight.

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The images are just screenshots from SolidWorks, it had to design it in CAD software so I can machine it, so the images are just a byproduct of that

I've also heard of the motors burning through on black powders, I havent figured out if/how I want to protect the rocket from it. This is the primary reason I went with top mounted motors rather than motors embedded in the base. If I end up casting motor covers as shown rather than 3d printing them, I'll probably add some fire retardant into the mix as filler, or aluminium powder.

Issus said:

I've also heard of the motors burning through on black powders, I havent figured out if/how I want to protect the rocket from it. This is the primary reason I went with top mounted motors rather than motors embedded in the base. If I end up casting motor covers as shown rather than 3d printing them, I'll probably add some fire retardant into the mix as filler, or aluminium powder.

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I've had a lot of burn throughs on spinny rockets. Especially the longer burn motors. Since the burn throughs are just above the nozzle, I found the best way to protect cardboard and wood is to make short motor mounts so the nozzle end is away from the affected body parts. I don't know how feasible this is on your design.

Do you happen to have a picture of a burn through you can post? If its not too long, I can easily just make the motor cover and motor tubes shorter so that section hangs out.

Issus said:

Do you happen to have a picture of a burn through you can post? If its not too long, I can easily just make the motor cover and motor tubes shorter so that section hangs out.

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Sure thing. In this photo, the E9's were centered in the motor mounts. (the far motor also burned through but was partially removed before I took the photo)

Issus said:

I was planning on glassing this thing, but to take 6x I1299's... wow, I think i'd need a few layers of carbon and a couple of kevlar to withstand that- holy crap. The motors would have 50mm of stickout on the top of the saucer, but you know what - i'd be fine with that! That would be quite the movie-esque ufo takeoff. The force on the outer ring though would be phenomenal, it would have to basically be able to support the front wheel of a car sitting on the hub, with the rim supported on blocks, I'm not even sure how I'd build it that strong... the frontal area on that rim is huge and not capable of handling transonic. That being said, I do love a good ambitious project, I think we have a plan for version 2 of this saucer!

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The only response you should have said:

blackbrandt said:

The only response you should have said:

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:rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl::rofl:





Now That is seriously funny!!

Going big is all well and good, but IMHO you'll get a much nicer flight on the 6 long burning I49s/59s. On fast motors it will disappear quickly...but will reappear fairly soon after burn out.