Cardboard/Plywood Parts to a 100k

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AlexBruccoleri

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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
Recovery would be required of all stages, but re-usability not necessarily. Nothing coming in ballistic, but hard landing would be fine.

I do not agree on minimum diameter. If the velocity is kept low, drag is not as bad. I believe nobody has done non-minimum diameter, which makes this all the more interesting. It is worth noting that cardboard tubing is very lightweight and a careful structure might be possible. Also soaking cardboard to make a composite would be un-allowed. I know messy work is subjective, but I figure that is a good rule to have.

Do you have any documentation on your stabilization system? I think that is the hardest part. In previous posts myself and others outlined a way to do a series of air starts to achieve staging-like performance. One could combine that with your stabilization system. My initial thought is the booster would be long burning and need stabilization. The upper stage could be fin stabilized and "punch it" without much worry about aerodynamic stresses.
 

dhbarr

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Recovery would be required of all stages, but re-usability not necessarily. Nothing coming in ballistic, but hard landing would be fine.

I do not agree on minimum diameter. If the velocity is kept low, drag is not as bad. I believe nobody has done non-minimum diameter, which makes this all the more interesting. It is worth noting that cardboard tubing is very lightweight and a careful structure might be possible. Also soaking cardboard to make a composite would be un-allowed. I know messy work is subjective, but I figure that is a good rule to have.

Do you have any documentation on your stabilization system? I think that is the hardest part. In previous posts myself and others outlined a way to do a series of air starts to achieve staging-like performance. One could combine that with your stabilization system. My initial thought is the booster would be long burning and need stabilization. The upper stage could be fin stabilized and "punch it" without much worry about aerodynamic stresses.
If you're not minimum diameter, you're not going to hit 100k with anything ever. Accelerating a cardboard balloon to 600mph and keeping it that way for two minutes is simply outside the realm of possible physics.
 

AlexBruccoleri

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If you're not minimum diameter, you're not going to hit 100k with anything ever. Accelerating a cardboard balloon to 600mph and keeping it that way for two minutes is simply outside the realm of possible physics.
Comments like this are going to make someone actually do this. Prior to seeing Gary's Hamster Dance rocket, I would have thought the same about 20k+ with a J motor. When I saw his facebook post and found out his rocket was not much tougher than an Estes rocket, I was pleasantly surprised and very impressed.
 

JimJarvis50

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Recovery would be required of all stages, but re-usability not necessarily. Nothing coming in ballistic, but hard landing would be fine.

I do not agree on minimum diameter. If the velocity is kept low, drag is not as bad. I believe nobody has done non-minimum diameter, which makes this all the more interesting. It is worth noting that cardboard tubing is very lightweight and a careful structure might be possible. Also soaking cardboard to make a composite would be un-allowed. I know messy work is subjective, but I figure that is a good rule to have.

Do you have any documentation on your stabilization system? I think that is the hardest part. In previous posts myself and others outlined a way to do a series of air starts to achieve staging-like performance. One could combine that with your stabilization system. My initial thought is the booster would be long burning and need stabilization. The upper stage could be fin stabilized and "punch it" without much worry about aerodynamic stresses.
Good luck on your contest.

The stabilization system is well-documented in the "Staging" section here on TRF. Easy to find. There are also lots of videos. Here's one where the system was used on a 175K flight. If you guys click like mad, we can get it over 100K views (see what I did there).

Jim

 

AlexBruccoleri

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Good luck on your contest.

The stabilization system is well-documented in the "Staging" section here on TRF. Easy to find. There are also lots of videos. Here's one where the system was used on a 175K flight. If you guys click like mad, we can get it over 100K views (see what I did there).

Jim


I will definitely check out your stabilization system and that is a great rocket and video. I saw it awhile back, and I think that is the most impressive Tripoli-style rocket to date in my opinion!

Anyway this thread is not a contest..... yet, but rather a discussion of ideas. I am hoping it will spark some action in the crowd of people with limited work shops, who want to fly high.
 

alexzogh

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Good luck on your contest.

The stabilization system is well-documented in the "Staging" section here on TRF. Easy to find. There are also lots of videos. Here's one where the system was used on a 175K flight. If you guys click like mad, we can get it over 100K views (see what I did there).

Jim



Jim, I'm responsible for at least three clicks on that video the last few years..... Still impressed every time I view it.

Alex
 

AstroAbaqus

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Good luck on your contest.

The stabilization system is well-documented in the "Staging" section here on TRF. Easy to find. There are also lots of videos. Here's one where the system was used on a 175K flight. If you guys click like mad, we can get it over 100K views (see what I did there).

Jim


I will go down the rabbit hole, but I have to ask, how hard was it to tune the controller for the active fin stabilisation? I watched many times that video, never thought I would have the chance to talk with the author.
 

heada

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If the concern over using composites is the dust that is produced when working with them, wouldn't you do the sanding/cutting/etc. outside anyway? I know that when I sand FG parts, I do it in the garage or in the backyard. Living in an apartment would have the same limitations, just do that kind of thing outside. You could even control the dust with liberal use of a spray bottle full of water.

While not ideal, getting pre-manufactured FWFG is now a given for nearly all standard rocketry sizes. There are some people making CF tubes for sale as well so making your own layups is not strictly required any more.
 

JimJarvis50

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I will go down the rabbit hole, but I have to ask, how hard was it to tune the controller for the active fin stabilisation? I watched many times that video, never thought I would have the chance to talk with the author.
Well, it is a little complicated. I've done a lot of calculations, but the information I really rely on is actual flight data. Basically, I know from experience that I can change the tilt of a rocket away from vertical by about 25°/sec with a 5° canard angle. A turn towards vertical is about 10°/sec. I just adjust those values for the flight and variables in question. A long rocket, such as the three stage, turns slower. From a control perspective, proportional control works pretty well, although we have added a derivative term to reduce oscillation. I should stop ...

Jim
 

AlexBruccoleri

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If the concern over using composites is the dust that is produced when working with them, wouldn't you do the sanding/cutting/etc. outside anyway? I know that when I sand FG parts, I do it in the garage or in the backyard. Living in an apartment would have the same limitations, just do that kind of thing outside. You could even control the dust with liberal use of a spray bottle full of water.

While not ideal, getting pre-manufactured FWFG is now a given for nearly all standard rocketry sizes. There are some people making CF tubes for sale as well so making your own layups is not strictly required any more.
I usually sand outside for fiberglass even when I am at a house where I can build rockets so I agree there. In my apartment in Boston, there are no outside places I can go sand for awhile. Also sanding is often required on lots of joints and going outside is not always feasible. I should back up again though. It is the whole build that is simpler and less messy with LOC-style parts. Cutting holes, sanding rings, gluing joints etc. It is just a lot easier than composites.

Also there is a bigger hole with my original idea. Most people who can travel to Black Rock or another suitable location for a 100k attempt, can probably find a place to play with composites.

I still think this is fun and interesting.
 

AlexBruccoleri

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Well, it is a little complicated. I've done a lot of calculations, but the information I really rely on is actual flight data. Basically, I know from experience that I can change the tilt of a rocket away from vertical by about 25°/sec with a 5° canard angle. A turn towards vertical is about 10°/sec. I just adjust those values for the flight and variables in question. A long rocket, such as the three stage, turns slower. From a control perspective, proportional control works pretty well, although we have added a derivative term to reduce oscillation. I should stop ...

Jim
Oh please go on! I looked through your post on guidance and did not finish, but what I saw was great stuff. In fact all your articles are treasure chests of good rocket know-how.

The guidance system is the key to getting a "weak" rocket to high altitude. Few people in hobby rocketry have experience with this and you an expert! If anyone tries this challenge for real, they should read your post carefully.

Thanks for sharing your experiences on this forum!!
 

JimJarvis50

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Oh please go on! I looked through your post on guidance and did not finish, but what I saw was great stuff. In fact all your articles are treasure chests of good rocket know-how.

The guidance system is the key to getting a "weak" rocket to high altitude. Few people in hobby rocketry have experience with this and you an expert! If anyone tries this challenge for real, they should read your post carefully.

Thanks for sharing your experiences on this forum!!
Thanks!

I'll share one piece of information. The attached graph is the correction the system made in the 3 stage flight (correcting from nominally 6° to about 1.5°. That made a big difference in the recovery distance. One thing that I have learned is that the canards create quite a bit of torque on the air frame. The oscillations in the tilt in the graph are due to air frame flexing and not changes in the control. On my test rocket, I applied carbon to a fiberglass aif frame to try to limit that bending, and the torgue can prevent parts of the rocket from separating. This issue would likely prevent the use of my three-stage approach on a weak rocket - there just isn't enough time in a coast to make a significant change in direction. If canards were used at the top of a weak rocket, it would be necessary to use small canards and small control actions to avoid tearing up the air frame. The idea would be to just keep slowly working back towards vertical over a long period. But, there is the weight penalty of keeping a system attached for an entire flight.

I did the two-stage flight in the video below a few years back. The stabilization system was on top of the rocket. The flight was two M motors, but the velocity was below Mach 1 for the entire flight. It only went to 23K though, and it's really hard to envision how to scale this up to 100K. Incidently, you can see the air frame flex I mentioned in the video (before I applied carbon to the rocket). That would be a real problem for a weak rocket.

Jim


Tilt Graph 3.jpg
 

AstroAbaqus

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Well, it is a little complicated. I've done a lot of calculations, but the information I really rely on is actual flight data. Basically, I know from experience that I can change the tilt of a rocket away from vertical by about 25°/sec with a 5° canard angle. A turn towards vertical is about 10°/sec. I just adjust those values for the flight and variables in question. A long rocket, such as the three stage, turns slower. From a control perspective, proportional control works pretty well, although we have added a derivative term to reduce oscillation. I should stop ...

Jim
Thank you very much for the reply, I started to look at your thread and is really nice to see the entire development. My experience with feedback control is mainly with satellite so very slow corrections. I think this is definitely something I will try after being a little more experienced. By the way, that was an amazing flight!
 

manixFan

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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.
Even though I have plenty of space outside to sand, there are times I want to sand indoors for a variety of reasons. The answer (for fiberglass) is wet sanding, which I do even when I’m outside. (And something you can’t do with wood.) I have a large utility sink I use, but a tub or shower would certainly work. It doesn’t take much water to keep the dust completely contained. I also drill a lot of holes with a set of pin vises. I have some aggressive bits (drill on contact) that will drill though glass tubing pretty easily. Again, a little water keeps the dust contained.

Most epoxies don’t generate a lot of fumes, which helps keep your partner happy. I use System Three which I consider to be very low odor.

This has been a very interesting thread, and it’s great to see so many experienced flyers chime in. A good example of what makes this such a great forum.

Keep us posted on your builds, the LOC sounds great.


Tony
 
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AlexBruccoleri

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Thanks!

I'll share one piece of information. The attached graph is the correction the system made in the 3 stage flight (correcting from nominally 6° to about 1.5°. That made a big difference in the recovery distance. One thing that I have learned is that the canards create quite a bit of torque on the air frame. The oscillations in the tilt in the graph are due to air frame flexing and not changes in the control. On my test rocket, I applied carbon to a fiberglass aif frame to try to limit that bending, and the torgue can prevent parts of the rocket from separating. This issue would likely prevent the use of my three-stage approach on a weak rocket - there just isn't enough time in a coast to make a significant change in direction. If canards were used at the top of a weak rocket, it would be necessary to use small canards and small control actions to avoid tearing up the air frame. The idea would be to just keep slowly working back towards vertical over a long period. But, there is the weight penalty of keeping a system attached for an entire flight.

I did the two-stage flight in the video below a few years back. The stabilization system was on top of the rocket. The flight was two M motors, but the velocity was below Mach 1 for the entire flight. It only went to 23K though, and it's really hard to envision how to scale this up to 100K. Incidently, you can see the air frame flex I mentioned in the video (before I applied carbon to the rocket). That would be a real problem for a weak rocket.

Jim


View attachment 500405

This is great data! Thanks for sharing. The first thing that came to mind when John mentioned the need for guidance was how torque would affect a weak airframe. Why was your flight to 23k hard to scale up to a 100k?

Beautiful video by the way.
 

dhbarr

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Comments like this are going to make someone actually do this. Prior to seeing Gary's Hamster Dance rocket, I would have thought the same about 20k+ with a J motor. When I saw his facebook post and found out his rocket was not much tougher than an Estes rocket, I was pleasantly surprised and very impressed.
120s is an eternity. 5% additional diameter is enormous. There are exactly zero 100k+ non-MD flights. Not aware of any altitude or speed records held that way either.
 

AlexBruccoleri

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Even though I have plenty of space outside to sand, there are times I want to sand indoors for a variety of reasons. The answer (for fiberglass) is wet sanding, which I do even when I’m outside. (And something you can’t do with wood.) I have a large utility sink I use, but a tub or shower would certainly work. It doesn’t take much water to keep the dust completely contained. I also drill a lot of holes with a set of pin vises. I have some aggressive bits (drill on contact) that will drill though glass tubing pretty easily. Again, a little water keeps the dust contained.

Most epoxies don’t generate a lot of fumes, which helps keep your partner happy. I use System Three which I consider to be very low odor.

This has been a very interesting thread, and it’s great to see so many experienced flyers chime in. A good example of what makes this such a great forum.

Keep us posted on your builds, the LOC sounds great.


Tony
Wet sanding is a good idea! I agree it is debatable on what can be done in an apartment. Arguably apartment builds are insane for HPR but I am pushing onward anyway. Maybe I will start an "apartment build" thread and post pictures there. I have a fiberglass Nike Tomahawk kit next to me and I plan to build it in the pad. I did most of the messy sanding at a house though.
 

AlexBruccoleri

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120s is an eternity. 5% additional diameter is enormous. There are exactly zero 100k+ non-MD flights. Not aware of any altitude or speed records held that way either.
I am pretty sure Gary's rocket was 54 mm or close to that, and he would be second on the Tripoli altitude record for J motors. He would have beat many 38 mm minimum diameter attempts. An efficient thrust profile can go along way and 5% extra diameter is not a big deal. Also not sure why you mention 120s? It will take around 50s or less to get to thin air before the final stage lights.

 

CoyoteNumber2

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Most epoxies don’t generate a lot of fumes, which helps keep your partner happy. I use System Three which I consider to be very low odor.

Years ago I did a tip-to-tip layup on a four-inch rocket in my dorm room.

Sigh... Those were the days.
 

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New topic: Cardboard & Plywood cars in the Indianapolis 500.
 

boatgeek

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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...

Welp, I noodled this for a while and came to the conclusion that @JimJarvis50 knows what he's talking about (of course he does!). When I tried the Cluster of Doom approach, I ended up adding too much weight in the back, so I had to make the fins bigger, so I lost velocity and altitude, so... I could get a sort of reasonable rocket flying about Mach 0.3 with longburn motors (35s total under thrust in the sustainer alone!), but that isn't enough to get above the dense air before you need to light the sustainer. It's pretty much the same reason you don't see LH2/LOX first stages on orbital rockets--not enough initial thrust to get off the pad.

The fins were also getting big enough that I'm not convinced that even generous fillets could hold them on to the cardboard airframe. I think that you could make a 50-60K flight work on cardboard airframes with a recovered booster, but I think it would be hard to get more than that.
 

AlexBruccoleri

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Welp, I noodled this for a while and came to the conclusion that @JimJarvis50 knows what he's talking about (of course he does!). When I tried the Cluster of Doom approach, I ended up adding too much weight in the back, so I had to make the fins bigger, so I lost velocity and altitude, so... I could get a sort of reasonable rocket flying about Mach 0.3 with longburn motors (35s total under thrust in the sustainer alone!), but that isn't enough to get above the dense air before you need to light the sustainer. It's pretty much the same reason you don't see LH2/LOX first stages on orbital rockets--not enough initial thrust to get off the pad.

The fins were also getting big enough that I'm not convinced that even generous fillets could hold them on to the cardboard airframe. I think that you could make a 50-60K flight work on cardboard airframes with a recovered booster, but I think it would be hard to get more than that.
Try a 5.5" booster with an N1000 and try a cluster of 6x k250s around it. Air start them in pairs of two.

Also I think the first stage can go Mach .8 and I have feeling you can get to Mach 1.2-1.5 on the second.
 

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Try a 5.5" booster with an N1000 and try a cluster of 6x k250s around it. Air start them in pairs of two.

Also I think the first stage can go Mach .8 and I have feeling you can get to Mach 1.2-1.5 on the second.
I'd love to see your work on this one. An OR sim is an hour or two's worth of work, and will make many things clear... I found that the added weight of the airstarted motors offset the extra burn time. If you can make it work, more power to you.

Also, I think you may be breaking the laws of physics. A 98mm motor in the middle and 54mm motors on each side won't fit in a 5.5" diameter airframe without some very fancy cutting.
 

AlexBruccoleri

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I'd love to see your work on this one. An OR sim is an hour or two's worth of work, and will make many things clear... I found that the added weight of the airstarted motors offset the extra burn time. If you can make it work, more power to you.

Also, I think you may be breaking the laws of physics. A 98mm motor in the middle and 54mm motors on each side won't fit in a 5.5" diameter airframe without some very fancy cutting.
They need to be strap ons. I did my sim n1000-l400-k250 and it worked. I did not figure out how to do strap ons in Rock Sim. I may try that on a weekend.
 

JimJarvis50

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This is great data! Thanks for sharing. The first thing that came to mind when John mentioned the need for guidance was how torque would affect a weak airframe. Why was your flight to 23k hard to scale up to a 100k?

Beautiful video by the way.
If you decided to try a flight staying below Mach 1, as in the video, the time to apogee (assuming 600 ft/s average) would be 166 seconds. I haven't tried any simulations, but I suspect that there is no feasible combination of motors that could do this.

Jim
 

AlexBruccoleri

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If you decided to try a flight staying below Mach 1, as in the video, the time to apogee (assuming 600 ft/s average) would be 166 seconds. I haven't tried any simulations, but I suspect that there is no feasible combination of motors that could do this.

Jim
The rocket only needs to stay slow until 30-40k. That is the key to this. I am also not sure how slow is required. Testing the limits of clever LOC style construction would be fun. I bet mach 1.5 is doable.
 

DeeRoc29

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You definitely got your 15 minutes in with this thread, Alex. Now start building the rocket!
 
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