Cardboard/Plywood Parts to a 100k

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Okay it depends what you mean by punch it. I consider a K250 in a lightweight rocket punching it. An L1000 works well too, and certainly higher thrust is fine if the second stage can clear most of the atmosphere. Also my initial guestimate is right in line with the sims. "The rockets would likely need to be staged and the velocity low in the thicker parts of the atmosphere.", but that is not important. I agree a real-world rocket will not perform like this sim, but keep in mind a four stage (or air start) rocket is what I was thinking. If all the parts worked, such a rocket would reach extreme velocity in thin air and easily exceed 100k. I keep bringing up Gary's Hamster dance rocket because of how efficient it was. Yes no commercial motors match his thrust profile, but a collection of motors can in a relative sense.

Anyway the point John Derimiggio brought up about guidance is very valid. This rocket will turn badly as it hits the upper-air winds. A guidance system takes this to a whole new level of hard.

I should back up now and get to my original point. I think more can be done with LOC Precision style components than most think can be done. I also suspect higher speeds are possible than what I initially thought. It is a a fun space to explore.

Perhaps the takeaway from this discussion to anyone reading is optimism. You do not need a professional-grade machine shop or advanced composite shop to build some very capable rockets. Though a word of caution. Staging and air starts require lots of care to be safe, especially with big motors.

Finally I have no interests in trying this challenge myself. My challenges are much more down to earth such as convincing my wife a porta potty "isn't that bad" at a launch. All of my current projects are aimed at the fields/waivers I have access to, which are modest, but still great fun.

Sorry for jumping in, but I have read the whole post and I found really interesting.

Guidance: I am pretty sure that a lot of HPR, single-stage or multi-stage did not have implemented any guidance at all. TVC, because of this we are discussing, is something very hard to implement. When I say implement, I refer to the creation of a system and its proper actuation. Especially for the relatively "short" burn of these engines and the lifting capability, is very difficult to house any type of guidance. I saw people using fins with actuators, but this was done more for the fun of doing some particular trajectory rather than actually navigating.

Materials: I totally get your vibes, and I think if this is done safely there is nothing bad in trying and fail. I love doing things and pushing limits. Indeed is possible to increase the strength of the tube by using more conventional materials like wood dowels to increase rigidity. However, the main issues are the final weight and last but not least the actual space left between the airframe and motor tube. When you fly that high, your design constraints start to look more as a real sounding rocket rather than an amateur one. So every gram you add, if is not doing something is wasted. This is why, in my opinion, if you really want to go extremely high you have to master very well minimum diameter, but this then leaves us with the point that others mentioned, without exotic materials is very hard to do. If you go minimum diameter than you do not have space internally to provide more rigidity.

I would love to join the race but despite I do stuff like that during my daily job I am not even closer to complete my lvl 1 and 2 bird. But I will follow closely :).

Ps I totally understand your point of living in a flat. I used to have a flat with an immense garage at my parent house, now I live in my own house which is nice but I have no space like that and convincing my wife to have a cnc somewhere in the living room will be hard xD, but she is an engineer she will appreciate hopefully xD
 
Sorry for jumping in, but I have read the whole post and I found really interesting.
No need to apologize and thanks for commenting.

Regarding guidance. This is not too bad a problem depending on the goal. My thought would be to keep the rocket pointed to the Zenith. I am not sure how easy that would be, and I do not have much hands-on guidance experience so I really cannot comment too much.

Regarding minimum diameter. I disagree that is a requirement. The goal is to keep the drag down via low speed. LOC tubing is so light, going a little thicker will still be okay for weight, and having space for well engineered structures is likely important.

Three issues come to mind with minimum diameter. 1. Fin attachment will be substantially weaker than through-the-wall. 2. The glue joint will weaken from the casing temperature. This will force you into using heat-resistant epoxies and go down that rabbit hole. 3. The stress on the coupler will very high and there is little space for a "thick" coupler. That being said, no harm in coming up with a design and seeing how it comes together :)
 
As a LOC "parts" flier since 1991 I love this thread, and innovation almost always happens after somebody has come to the conclusion that, "It can't be done." Pretty sure that those were the words spoken to the Wright brothers long before they succeeded!

Now, I also fly fiberglass and frankly prefer it for flying mach+, but this is a challenge. I have already flown...... hmmm how to say this..... "past the speed of Loc tubing" if you know what I mean. It was on an Aerotech K-550 or K-1100 in a 4" LOC parts rocket with aircraft grade plywood fins that the fins literally delaminated on the way up. Some on this thread are quick to point out why it can't be done. That's ok, but except for specific information on specific limitations its not particularly helpful. Alex is laying out a challenge that is spectacularly difficult, but that does not mean that it is impossible.

Here's an obvious question: What would it take from the rocketry community to get Gary to make that HamsterDance motor that he flew in a cardboard rocket to 22K available commercially? Maybe it would be too rough on a reloadable case, but how about single use? Think with me for just a second, that motor is not NOW available commercially, but I think I can guarantee that if Gary produced them for sale, that there would be a market! I'd buy one in a heart beat! Hey Gary! Are you listening in on this thread?

It is also very obvious that achieving this milestone would take a whole lot of testing and the lower atmosphere booster stages would be the first. Just getting to 30K feet with any LOC parts rocket would be a challenge. First booster with strap-ons to 10K, second booster to 30K, third booster to 60K, top stage to 100K? Who knows what a final configuration might be.

Just thinking here folks. I know that I can't be the only one who's been dreaming about this kind of thing for years. Sure, I've never thought about 100K feet before, but I've been thinking about 50k ever since I bought my first Adept Alts-2-50K lo these many years ago. Personally, I don't know that it can be done, but the process would be highly educational at the least.

Me, I'm going to start to think about those first 10K feet with LOC tubing. That much can be done and probably has been done already with commercial motors. Now to think about a configuration for a three stage dummy payload on top of that 10K rocket....... Hmmmmmmm.............................

Brad the "optimistic" "Rocket Rev.," Wilson
 
The assumption is that we need to maintain lower speeds at low altitude to enable the survivability of lower strength materials. Rather than staging what about intermitent burns to give a thrust-coast-thrust-coast etc profile until the air gets thinner. Again this is outside the realm of commercial motors probably. How about a 'magazine fed" sequence of smaller motors that are ejected after they burn out? I know its outside alot of boxes but that may be required for this type of mission.
 
The assumption is that we need to maintain lower speeds at low altitude to enable the survivability of lower strength materials. Rather than staging what about intermitent burns to give a thrust-coast-thrust-coast etc profile until the air gets thinner. Again this is outside the realm of commercial motors probably. How about a 'magazine fed" sequence of smaller motors that are ejected after they burn out? I know its outside alot of boxes but that may be required for this type of mission.
I was thinking something similar, but with commercial motors. Part of this thought experiment is to keep it accessible. Anyway here is my thought. 7 engine core, initial N1000 and 6 smaller motors. Maybe K250s? Light the N1000, let it coast, then light a pair of the K250s and play that game for 30 seconds.
 
As a LOC "parts" flier since 1991 I love this thread, and innovation almost always happens after somebody has come to the conclusion that, "It can't be done." Pretty sure that those were the words spoken to the Wright brothers long before they succeeded!

Now, I also fly fiberglass and frankly prefer it for flying mach+, but this is a challenge. I have already flown...... hmmm how to say this..... "past the speed of Loc tubing" if you know what I mean. It was on an Aerotech K-550 or K-1100 in a 4" LOC parts rocket with aircraft grade plywood fins that the fins literally delaminated on the way up. Some on this thread are quick to point out why it can't be done. That's ok, but except for specific information on specific limitations its not particularly helpful. Alex is laying out a challenge that is spectacularly difficult, but that does not mean that it is impossible.

Here's an obvious question: What would it take from the rocketry community to get Gary to make that HamsterDance motor that he flew in a cardboard rocket to 22K available commercially? Maybe it would be too rough on a reloadable case, but how about single use? Think with me for just a second, that motor is not NOW available commercially, but I think I can guarantee that if Gary produced them for sale, that there would be a market! I'd buy one in a heart beat! Hey Gary! Are you listening in on this thread?

It is also very obvious that achieving this milestone would take a whole lot of testing and the lower atmosphere booster stages would be the first. Just getting to 30K feet with any LOC parts rocket would be a challenge. First booster with strap-ons to 10K, second booster to 30K, third booster to 60K, top stage to 100K? Who knows what a final configuration might be.

Just thinking here folks. I know that I can't be the only one who's been dreaming about this kind of thing for years. Sure, I've never thought about 100K feet before, but I've been thinking about 50k ever since I bought my first Adept Alts-2-50K lo these many years ago. Personally, I don't know that it can be done, but the process would be highly educational at the least.

Me, I'm going to start to think about those first 10K feet with LOC tubing. That much can be done and probably has been done already with commercial motors. Now to think about a configuration for a three stage dummy payload on top of that 10K rocket....... Hmmmmmmm.............................

Brad the "optimistic" "Rocket Rev.," Wilson
Thanks for the thoughts! The Laser Loc 313 can handle a K250 if built well. Unfortunately it is unavailable on the LOC website :(
 
Hi Alex,
When you have another challenge, it might be better to take a step back. And if you are not prepared to participate in the challenge you propose, suggest it as a hypothetical exercise. If that boat floats, take it forward to the next stage. This particular boat had so many holes in it, it didn't even reach the iceberg it was inevitably going to hit.
That said, I sincerely admire the way you took on all comments and answered them. :) That's a life skill there........
Norm
 
Hi Alex,
When you have another challenge, it might be better to take a step back. And if you are not prepared to participate in the challenge you propose, suggest it as a hypothetical exercise. If that boat floats, take it forward to the next stage. This particular boat had so many holes in it, it didn't even reach the iceberg it was inevitably going to hit.
That said, I sincerely admire the way you took on all comments and answered them. :) That's a life skill there........
Norm
My initial post said this was an idea for a challenge. It is meant to be a discussion. I also do not see why I need to participate in my own challenge. It is a challenge for those that want to push the envelope, show off their skills and try something hard and creative. I am not looking to do any of that presently with my hobby time. Anyone who wants to actually try this will need to do it at a desert as well, and that limits this to a narrow crowd. Though as stated previously, one could test a lot of the flight events and key structures at launches out east with smaller motors and dummy payloads.

Also the only hole I see so far that is serious is guidance. I do not have a good feel for guidance issues, thought maybe someone on this forum can comment more on how badly rockets turn, and ideas to correct that.
 
A question related, perhaps, to this thread: What's the largest number of high-power motors any amatuer rocketeer has staged in a flight?
 
A question related, perhaps, to this thread: What's the largest number of high-power motors any amatuer rocketeer has staged in a flight?
I believe 5 stages have been demonstrated but not in a "performance" rocket. I think 3 stages is the limit for the high altitude attempts. After giving it more thought, I am liking air starts more. Keeping this rocket as compact as possible will be helpful. I am not aware of any rockets that used air starts and staging to push the limits. I also am far from an expert in what others have tried and would love to hear more about past projects.
 
In order to use "paper" tubes, I think it would be necessary to reinforce all of them, using full-length couplers. Since Phenolic used in Rocket tubes is "paper", the full-length couplers might provide additional rigidity, if they were Phenolic.

Plywood Fins could work, but Fin Planform would be critical to avoid flutter and provide minimal Drag. Plus, they would be considerably thicker than 1/4", Diamond-Wedge airfoiled, and have a solid Hardwood Leading Edge to prevent de-lamination, caused by the airflow over it.

Dave F.
 
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Let's consider the most common 100k rocket: MD 4" to 3" long burn two-stage.

I think LOC tubing can take take the stresses. The part of the tubing around the motor is merely a sleeve loaded in tension - fiber tubing is enormously strong in this application. In the booster, an ISC made of a solid stack of 1/4 ply centering rings (essentially making it solid wood) will probably take the thrust and side loads, leaving a single weak point where the CR stack/thrust ring stops. The sustainer can be built in a similar fashion.

The fins, on the other hand, seem guaranteed to fail. The fin/body joint of a surface mount fin is miniscule, and there isn't enough adhesion area. Should you be lucky enough to form a strong bond, the tube will simply delaminate underneath. Should you be lucky enough for the fin to stay on the tube and the tube to stay together, plywood will flutter.

You could beat this by building a 5.5 to 4" booster and a 4" to 3" sustainer, since TTW 1/4 ply fins seem to survive up to M1.5 or so. The extra internal structure will at least keep the fins on. Fly under M1.5 and there's a fighting chance they won't flutter if you pick a good geometry.

Now you're fat and draggy, so you will need a third stage at minimum.

Three stages, all long-burn motors to stay under M1.5, is a whole lot of time under thrust. A vehicle like that is likely to end up making a long, ugly gravity turn under thrust.

Now you need active stabilization.

The only solution I can see: Three to four stages, active stabilization and a long burn motor on all of them.

Nobody is going to do it.
 
Let's consider the most common 100k rocket: MD 4" to 3" long burn two-stage.

I think LOC tubing can take take the stresses. The part of the tubing around the motor is merely a sleeve loaded in tension - fiber tubing is enormously strong in this application. In the booster, an ISC made of a solid stack of 1/4 ply centering rings (essentially making it solid wood) will probably take the thrust and side loads, leaving a single weak point where the CR stack/thrust ring stops. The sustainer can be built in a similar fashion.

The fins, on the other hand, seem guaranteed to fail. The fin/body joint of a surface mount fin is miniscule, and there isn't enough adhesion area. Should you be lucky enough to form a strong bond, the tube will simply delaminate underneath. Should you be lucky enough for the fin to stay on the tube and the tube to stay together, plywood will flutter.

You could beat this by building a 5.5 to 4" booster and a 4" to 3" sustainer, since TTW 1/4 ply fins seem to survive up to M1.5 or so. The extra internal structure will at least keep the fins on. Fly under M1.5 and there's a fighting chance they won't flutter if you pick a good geometry.

Now you're fat and draggy, so you will need a third stage at minimum.

Three stages, all long-burn motors to stay under M1.5, is a whole lot of time under thrust. A vehicle like that is likely to end up making a long, ugly gravity turn under thrust.

Now you need active stabilization.

The only solution I can see: Three to four stages, active stabilization and a long burn motor on all of them.

Nobody is going to do it.
You summarized a lot of my post on this. The stabilization part is a tough catch. I agree its unlikely anyone would attempt this, but maybe. It would be a fun project with a lot of milestones.
 
Also for anyone that is interested in a more "real life" comment. Jay Turicik at LOC Precision agreed to make me a custom 5.5" Magnum kit. This is going to essentially be a "Magnum 4E" since the major change is a 98 mm motor mount. I am not looking to push boundaries with this and it looks like a very doable "apartment build". The main reason I asked for 98 mm is the K458, though I am worried it will weigh too much. I may need a long rail. It is a step in the right direction for those looking to push it. I may do a build thread.

I kinda pushed the limits recently with "apartment building". My daughter looked extra cute holding an Estes Goblin my wife built. Naturally I had to build another Goblin so I bought the 7.5" Goblin from LOC. This rocket is insanely silly but I was determined. After hours of sanding the giant 3/8 fins, I managed to put a conformal coating of wood dust everywhere. I did manage to put something together with a custom interior and a 98 mm motor mount. My work area was about 20 square feet and this rocket is quite big, but it came together nicely for an "apartment build". My wife is a saint for putting up with this. My take away was 7.5" LOC rockets are the cusp of what my apartment can handle. A 5.5" should be doable.
 
What would be considered "cheating" in such a contest?

I assume epoxy and other resins are allowed for construction. How much exactly could be used? There are certain polyimides that could dramatically increase the strength and structural integrity of LOC parts - to the point they could have the mechanical characteristics of a phenolic (cotton or paper) if done properly. Other epoxies could be used as ablative material - especially if the nosecone is not required to be wood or cardboard - Most LOC kits use a polypropylene nosecone, so if it must be cardboard or wood, I hope you have a big lathe in your apartment! Also assume we can use an aluminum motor case - haven't seen any wooden ones, and if we are going to have to use carboard motors, that would be more Estes D motors than I could imagine. If all of this is 'legal' (motor cases, epoxy, polypropylene nosecone) then we can begin the thought experiment......


The first stage would just be a flying case. I would go with an Aerotech M685 (75/7680 - 11.3 second burn). I would forgo fins on the case in favor of a slightly flared, cantilevered rear 'skirt' which would be sacrificial at low altitude, and medium speed (~6 seconds into the burn would be more than enough). This will help with aerodynamic stabilization early in flight while inducing spin stabilization (the cantilevered part) for the rest of the journey. The interstage coupler could either be epoxied onto the top of the motor case or mechanically connected using the 1/4 eyebolt. You would need a large tower to ensure sufficient off the rail velocity.

For the second stage, I would think about using a secant ogive nosecone in which the maximum diameter would be slightly larger than the base diameter (think Honest John). Would help aerodynamically stabilize like a forward ring fin, and if it's allowed to be non-cardboard, could take much of the atmospheric drag, especially with the proper 'epoxy' and assuming its maximum diameter is at least halfway between the first and second stage base diameter (11mm to be exact - (76-54)/2). If built right, you could insure the interstage coupler was in a low-pressure zone with minimal friction. The second stage motor would be the Loki M-1378 (54/4000 3.9 second burn).

This doesn't quite Sim to 100,000 feet, but it gets close, and I don't think rocksim is giving my small fins the same credit that a flaired skirt should.

I say all of this with a bit of a wink and a smile, as I've already found the speed of carbon fiber several times - at least with surface-mounted fins and the limits of my skills..... it was well below what you would need for this ride.


Alex
 
What would be considered "cheating" in such a contest?

I assume epoxy and other resins are allowed for construction. How much exactly could be used? There are certain polyimides that could dramatically increase the strength and structural integrity of LOC parts - to the point they could have the mechanical characteristics of a phenolic (cotton or paper) if done properly. Other epoxies could be used as ablative material - especially if the nosecone is not required to be wood or cardboard - Most LOC kits use a polypropylene nosecone, so if it must be cardboard or wood, I hope you have a big lathe in your apartment! Also assume we can use an aluminum motor case - haven't seen any wooden ones, and if we are going to have to use carboard motors, that would be more Estes D motors than I could imagine. If all of this is 'legal' (motor cases, epoxy, polypropylene nosecone) then we can begin the thought experiment......


The first stage would just be a flying case. I would go with an Aerotech M685 (75/7680 - 11.3 second burn). I would forgo fins on the case in favor of a slightly flared, cantilevered rear 'skirt' which would be sacrificial at low altitude, and medium speed (~6 seconds into the burn would be more than enough). This will help with aerodynamic stabilization early in flight while inducing spin stabilization (the cantilevered part) for the rest of the journey. The interstage coupler could either be epoxied onto the top of the motor case or mechanically connected using the 1/4 eyebolt. You would need a large tower to ensure sufficient off the rail velocity.

For the second stage, I would think about using a secant ogive nosecone in which the maximum diameter would be slightly larger than the base diameter (think Honest John). Would help aerodynamically stabilize like a forward ring fin, and if it's allowed to be non-cardboard, could take much of the atmospheric drag, especially with the proper 'epoxy' and assuming its maximum diameter is at least halfway between the first and second stage base diameter (11mm to be exact - (76-54)/2). If built right, you could insure the interstage coupler was in a low-pressure zone with minimal friction. The second stage motor would be the Loki M-1378 (54/4000 3.9 second burn).

This doesn't quite Sim to 100,000 feet, but it gets close, and I don't think rocksim is giving my small fins the same credit that a flaired skirt should.

I say all of this with a bit of a wink and a smile, as I've already found the speed of carbon fiber several times - at least with surface-mounted fins and the limits of my skills..... it was well below what you would need for this ride.


Alex
Good question on glue. I suppose I should back up and discuss the spirit of the original post. The idea behind this challenge is to reach 100k with "accessible" materials and construction techniques. Another part of this, but not necessarily required, is clever aerodynamics to reduce the forces on the airframe. Here are a few specific responses:

1. Any glue is fine if it is apartment safe and you do not need a lot of it where it would be hazardous or extremely messy. Soaking the airframe or fins in resin would not be allowed, but using a little West Systems epoxy on the joints would be fine.

2. Plastic nose cones from LOC are fine. I should have mentioned that before.

3. Small amounts of threaded rod are fine too. LOC sells them for ebays and they are certainly in the spirit of an apartment build. You could even use them in a coupler too.

Lastly your design concepts are exactly the kind of thinking this post was supposed to evoke. Thanks for sharing!
 
I am noodling a design with a 7.5" booster with a central 75mm motor and a cluster of 54mm motors around it. The sustainer would probably be a 4" airframe with a 75mm motor mount. I'm guessing (still to be "proven" in OR) that with clever motor selection and airstart sequences in the booster, you could essentially replicate the 30-second burn discussed earlier (yes, I'm stealing the idea from @jderimig --all the best ideas are stolen!) and get up around 30-40K feet before separating the booster and then starting up a longburn motor. I'm assuming that one would have a vertical trajectory system on board. Give me a bit and I'll see what OR says...
 
I suspect the only way to design such a rocket would be for "recovery optional" of the lower stage or stages. If a heavy second/third stage sits on top of a 3-foot cardboard recovery section, I would expect that to be a likely failure point. The idea would be to keep this section of cardboard as short as possible. There are places where a rocket can be flown this way. If there's no rule about successful recovery of those sections, then the task is easier.

I also suspect that such a rocket would have to be minimum diameter. It is very difficult to fly non-minimum-diameter rockets to 100K, fiberglass or otherwise, due to the increased drag. I'm not sure it has ever been done? With minimum diameter, you have the motor tube to keep the air frame round. This is critical to keeping the fins on. I don't know about cardboard delamination, having never built a cardboard rocket, but I believe it might be possible to soak that portion of the air frame with epoxy to form essentially a composite structure with the cardboard. Again, if there's no rule ...

Active stabilization at the top of the rocket won't be practical. The weight of a system alone would be difficult to overcome. When I use active stabilization on high altitude flights, it is by locating the stabilization system between the first and second stages to "correct" the trajectory at that point in the flight. Then, that weight is discarded for the remainder of the flight. I've tried this three times on high altitude flights, and one time, it actually worked. Making this portion of the system out of cardboard would be pretty tough.

Jim
 
Alex, why do you consider fwfg not apartment safe?
I consider drilling and sanding fiberglass fairly hazardous in a living space. It is doable if you are *very* careful but unlikely. A small fiberglass rocket is possible, but something like the AeroPac rocket seems unfeasible. This is certainly a gray area and one could certainly lay-up composites in their living room if they were both determined and their living partners tolerated such rocket insanity. My assumption is the builder is living with other non-rocket people and needs to keep their house livable and clean.
 
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