Cardstock Rockets-Stomp / Compressed Air Powered!

[mbauer]

Hello,

I design cardstock rockets as a hobby. Started with small stomp rockets, learned from the first ones, now they go higher from lessons learned. Most recent designs now use a PVC airtank and up to 90 psi air pressure.

Stomp Rocket launcher takes 5-minutes to make, parts are slip fit / no gluing required, cost is less than $5 here in Alaska.

The air tank idea was a PDF download that is no longer available from Steve Spangler's website. Easy to make for around $60 using Home Depot items.

First models were created to test models, now that I have Peter Alway's Rockets Of The World book, models are getting to be more scale like. However they don't have any extra detail parts, for compressed air flight, drag and weight really cut into the altitude.

Anyway here are some photos of the rockets, some have flown, a couple haven't yet (4ft tall X-15 & the 10ft tall Saturn V).

Other posts to this thread will show short video's of some in flight.

Older Stomp Rockets






Latest Design:


More threads and photos to continue.

Mike Bauer

 

[mbauer]

A couple photo of some of the Stomp Rocket Gliders and a few photos of them in action.



Flight Photos:




These all use a replaceable nosecone. The nosecone gets bent after a hardlanding, just print a new one, make it and the model looks new again. An added bonus of the replaceable nosecone is that they act as a shock-absorber. They compress air forces it out when they land nose first.

Mike

 

[mbauer]

This rocket is part of a complete set of Experimenter Stomp Rockets. Designed for class room use.

The set includes threee different Altitude test Rockets, plus several Stability test rockets.

All Rockets are the same diameter. The altitudes set has 3-rockets each a different length. They show how length works with the single impluse of the Stomp Launch.

The stability set has several rockets with the stabilizer fins in different locations. Included as a bonus is a page of different shaped fins for instant kit bashing. These Rockets are a safe way to test stability! One has a set of fins at the bottom, middle and near the top (it actually flies horizontal after it slows down from the stomp).

Cold Day Testing the longest Altitude Rocket:






The last photo shows the replaceable nosecone. It can be pulled out and make several more flights before it actually splits and won't cushion the landing any more.

The Experimenter set was designed after I gave a few classes to some summer space campers at the local Challenger Learning Center here in Kenai.

Mike

 

[mbauer]

These are the latest designs I've been working on. They are big! Plan to do a whole set of 1/32 Scale size rockets of NASA manned flight vehicles from the Mercury Redstone through Saturn V.

Just recently redrew the Mercury Atlas, and Gemini Titan models to a better scale thanks to Peter's book. Additional photos supplied by an online friend helped with the panel lines and rivet patterns. He also supplied photos to help complete the 1/12 scale Mercury Redstones (both Freedom 7 & Liberty Bell 7).

If the 1/32 scale Atlas and Gemini builds look ok, they will also be done at 1/12 scale to match the Mercury Redstones. The Mercury Redstones will soon be for sale. A friend is working on converting to Black Powder.

6ft Tall Saturn V not to scale-notice the Estes version next to it! Estes Cato'd years ago, plan to fix it one day! Upper section was replaced after rocket buried itself when my ex took the kids to launch and the salesman at the LHS sold her the wrong D-12 (too much delay).


Other Rockets and the launch system:





More photos to follow. Only can do 5 at a time.

Mike

 

[mbauer]

Here are some more photos of the Air Rockets, videos to follow:
1/32 Scale Saturn V (has not flown yet)



Saturn 1B and friends (the SR71 is not a rocket-just a free flight glider):


Mike

 

[mbauer]

Camera doesn't have sound and is old digital, but to give an idea how these fly, here are some videos:
[YOUTUBE]s2BJY_ct_ZA[/YOUTUBE]

[YOUTUBE]JO1HKRFicZw[/YOUTUBE]

F104 Stomp Glider:
[YOUTUBE]IlvMdpDD8_8[/YOUTUBE]

Mike

 

[mbauer]

Here is the High Altitude Test:
[YOUTUBE]zajSFILs4P4[/YOUTUBE]

It did several flights that day:
[YOUTUBE]ts8qafUUoVw[/YOUTUBE]

Ok Now a Stability Test Rocket Flight this is the Three location Stabilizer rocket:
[YOUTUBE]jnxPiSm0CR4[/YOUTUBE]

Mike

 

[mbauer]

Here is the 6ft Tall Saturn V 4th flight, this was the last one it made. Flight 5 it blew up with 90 lbs of launch air pressure.
[YOUTUBE]u-HFL79Rd-M[/YOUTUBE]

Here is the 1/12 Scale Mercury Redstone Flight. This was the only flight this Alpha build has done to date. I still have it and plan to do more testing with it. A second Redstone was built for testing a wind-up timer release for the parachute. This very first model will use a drag deployment system I've designed and plan to test.
[YOUTUBE]s_E29l4hnuc[/YOUTUBE]

One of the reasons why I became a member here was to learn more about the newer parachute deployment sytems, and if they might work for these air rockets!

Mike

 

[mbauer]

Here is a couple of videos when I tried higher Pressures at launch. Rocket was rebuilt several times until it finally turned into confettii:
[YOUTUBE]H54Iwkb9nmk[/YOUTUBE]

And then this happened:
[YOUTUBE]Imsad7uboME[/YOUTUBE]

Lessons learned:
1) PVC tubing has a bow in it. From now on the "Launch Barrell" is now metal conduit (straighter tubing by far)
2) Internal cardstock PSI Tube was not able to handle air pressure above 85 lbs tank pressure. Going to try a different sized internal cardstock PSI tube. Smaller diameter should handle higher PSI allowing up to 100lbs launch pressure.

Mike

 

[billspad]

Nice stuff but a word of advice. In case you're not aware, of all the materials available for a compressed air tank, PVC is probably the least safe. When it fails it shatters and sends sharp pieces flying and it gets more brittle the colder it gets.

Here's a random article warning about the dangers.

It appears that ABS will work and it costs about the same and is easy to work with.

 

[rockets4kids]

Several of us have been doing compressed air rockets for a while now. Check the archives for more details. My interest in compressed air rockets was driven primarily as a means to quickly and easily test my homebrew flight computers. As such, all of mine were purely functional and had nothing in the way of aesthetics. To keep field gear minimal I used a metered propane spud gun as my launcher.

The secret to working with higher pressures is to use composite paper tubes. I use kraft paper and PVA+wheatpaste glue. Wet out the kraft paper completely on a large plate of glass before rolling. You'll be amazed at how strong and light the resulting tubes are. I also use 3/16" plywood as the forward bulkhead.

 

[mbauer]

Nice stuff but a word of advice. In case you're not aware, of all the materials available for a compressed air tank, PVC is probably the least safe. When it fails it shatters and sends sharp pieces flying and it gets more brittle the colder it gets.

Here's a random article warning about the dangers.

It appears that ABS will work and it costs about the same and is easy to work with.

Thank you for the warning.

Before I decided to try the PVC, did some research on the different qualities. Several engineering websites have different properties listed for each type.

Overall the general strength of PVC is what was used to make my launch system. Another reason was the only ABS I can get here in Kenai without special ordering is abs-dwv, which has a foam core and is not pressure rated.

Interesting thing about any of the ABS pipe is there is no bursting limit posted for it on any of the sites I visited.

Here is the working pressures of different types of Schedule 40 - 4" O.D. ABS that is rated at 73 deg F:
Type / Rating Working PSI
1208 / 90#
1210 / 110#
1316 / 205#
2112 / 200#

Schedule 40 - 4" O.D. PVC has the following ratings @ 73 deg F: (These are min industry standards)
Working PSI / Bursting PSI
133# / 710#

My pipe is stamped with the following: (this is what you look for, different brands are rated differently)
Working PSI / Bursting PSI
220# / 1785#

I bought a more expensive PVC than available at home depot. Making sure it was made in the USA.

Am I wrong in my numbers? Notice that you have plumbing experience.

Mike

 

[mbauer]

Several of us have been doing compressed air rockets for a while now. Check the archives for more details. My interest in compressed air rockets was driven primarily as a means to quickly and easily test my homebrew flight computers. As such, all of mine were purely functional and had nothing in the way of aesthetics. To keep field gear minimal I used a metered propane spud gun as my launcher.

The secret to working with higher pressures is to use composite paper tubes. I use kraft paper and PVA+wheatpaste glue. Wet out the kraft paper completely on a large plate of glass before rolling. You'll be amazed at how strong and light the resulting tubes are. I also use 3/16" plywood as the forward bulkhead.

I've seen the launcher you use with the propane charge. Very, very cool! Neat way to make sure the charge is metered correctly each time.

I've also seen the "Homebrew" air cannon on flickr. Is this yours? I want one!!!

Don't know if I want to go as far as using plywood for the bulkhead, but, I saw the thread on making cardstock tubes by wrapping around a mandrel and then gluing drywall tape in layers. Also the thermosetting mentioned makes sense. Paper doesn't make shrapnel, just confettii.

I have a roll of heavy weight kraft paper that has been collecting dust, might have to try your method.

I don't want to go any higher than 100 PSI indicated to launch for safety reasons. I've tested my system to 125#. If I can get one of my cardstock tubes to handle the 100 PSI without wrapping and gluing, I'll be happy.

At 1.5lbs for the rocket weight, the highest I've been able to do is 85lbs launch PSI. That was with a 1.25" diameter internal PSI tube. By downsizing the diameter I plan to test it again before going to different construction methods...

What kind of pressures have you launched at? What kind of rocket weights?

Mike

EDIT: Just searched the TRF archives. Tried several different search terms with air, compressed air, and rockets = no joy. Then tried to search your username, said it was an invalid name. Decided to look in propulsion, made it through 20 of the 124 pages, before deciding to ask you to be a little more specific. Can you help me with what forum these compressed air rockets are listed under? Maybe a good title, "compressed air" returns nothing available... Lots of Air-Start comments in the propulsion forum title...

 

[billspad]

Am I wrong in my numbers? Notice that you have plumbing experience.

I have way too much plumbing experience.

I"m sure your numbers are right but I noticed that you're in Alaska and you should check the ratings at the temperature you'll be using it. I've dropped PVC pipe on a cold winter day and had it shatter. I wouldn't want to see that happen with pressure in it.

 

[mbauer]

I have way too much plumbing experience.

I"m sure your numbers are right but I noticed that you're in Alaska and you should check the ratings at the temperature you'll be using it. I've dropped PVC pipe on a cold winter day and had it shatter. I wouldn't want to see that happen with pressure in it.

Only thing I've seen on temp. is that above 73 deg F PVC can loose up to 20% strength as temp increases, most of my launching is in the summer between 55-65 deg F. Very little winter testing because of what you mention when it gets cold. Stomp Rockets work great, but the bottle breaks real easy...

All of the higher testing (above 80lbs PSI), is done solo. Have heavy gloves, eye protection and full sleeve shirts. Been thinking of wrapping PVC Launcher (tank-pipe) with a welders fiberglass "fire" blanket to stop pieces from flying in all directions, that would hopefully control it to just the ends...

I don't trust the PVC totally!

Mike

 

[billspad]

Only thing I've seen on temp. is that above 73 deg F PVC can loose up to 20% strength as temp increases, most of my launching is in the summer between 55-65 deg F. Very little winter testing because of what you mention when it gets cold. Stomp Rockets work great, but the bottle breaks real easy...

All of the higher testing (above 80lbs PSI), is done solo. Have heavy gloves, eye protection and full sleeve shirts. Been thinking of wrapping PVC Launcher (tank-pipe) with a welders fiberglass "fire" blanket to stop pieces from flying in all directions, that would hopefully control it to just the ends...

I don't trust the PVC totally!

Mike

The welder's blanket sounds like it's worth doing.

When you come right down to it, anything that you use to move a rocket that involves storing a lot of energy in a small space should never have your total trust.

 

[rockets4kids]

What kind of pressures have you launched at? What kind of rocket weights?

It is worth noting that pressure alone doesn't say too much. You need to know the volume of your storage tank and the volume of your launch tube for it to be at all meaningful. The diameter of the valve can also be a seriously limiting factor as well.

I cannot recall the weight of my rockets, but those without electronics were quite lightweight. Everything I have done is minimal diameter. Getting the weight down on the avbay, electronics, and recovery system was by far the biggest challenge.

For combustion launchers, the power is driven almost entirely by the size of the combustion chamber, as this limits the amount of oxygen available for combustion. Because propane combustion is a heat producer rather than a gas producer, running lean (less propane) actually produces better results. I have a collection of combustion chambers of different volumes to control altitude. I also have a collection of barrels of different diameters. I have standardized on 1 1/2" PVC threads so I can mate any combustion chamber to any barrel.

According to what I have read on some of the potato cannon forums, peak pressures are only about 40 PSI. If this is actually correct (i.e. no measurement error) then it could go a long way towards explaining why so few potato cannons made from PVC actually suffer catastrophic failure. I do have a pressure logging rig for my EX motors, but the only sensor I have at the moment is 2000 PSI. At some point I will try to pick up a 200 PSI transducer to see what is *actually* going on inside the combustion chamber.

 

[mbauer]

It is worth noting that pressure alone doesn't say too much. You need to know the volume of your storage tank and the volume of your launch tube for it to be at all meaningful. The diameter of the valve can also be a seriously limiting factor as well.

I cannot recall the weight of my rockets, but those without electronics were quite lightweight. Everything I have done is minimal diameter. Getting the weight down on the avbay, electronics, and recovery system was by far the biggest challenge.

For combustion launchers, the power is driven almost entirely by the size of the combustion chamber, as this limits the amount of oxygen available for combustion. Because propane combustion is a heat producer rather than a gas producer, running lean (less propane) actually produces better results. I have a collection of combustion chambers of different volumes to control altitude. I also have a collection of barrels of different diameters. I have standardized on 1 1/2" PVC threads so I can mate any combustion chamber to any barrel.

According to what I have read on some of the potato cannon forums, peak pressures are only about 40 PSI. If this is actually correct (i.e. no measurement error) then it could go a long way towards explaining why so few potato cannons made from PVC actually suffer catastrophic failure. I do have a pressure logging rig for my EX motors, but the only sensor I have at the moment is 2000 PSI. At some point I will try to pick up a 200 PSI transducer to see what is *actually* going on inside the combustion chamber.

Yes, the volume is important. When making the bigger tank in the Redstone Photo/video, made sure to have enough. Figured the downstream pipe volumes, and also when the rocket was fully extended (Rocket interal PSI tube length added to the piping length). The 6ft tall Saturn V photos show the smaller tank and the "U" shape to get the volume. With all the bends it created downstream turbulence, that Mark's Engineering Book v8 said needed several feet of downstream piping to equal out.

Newer tank is 4" O.D. and three feet long. It has plenty of voulume for 1-1/4" piping. Using a 1" 1/4 turn ball valve to release tank with. Piping is 1" until after the 90 deg bend to go vertical. Using some adapters, I can change out launch Barrell size from 1/2" thru 1-1/4". Was having issues with the 1" on the Saturn V, so back to 3/4" hoping it will better handle the pressures.

What kind of parachute deployment electronics do you use?

Mike

 

[mbauer]

The welder's blanket sounds like it's worth doing.

When you come right down to it, anything that you use to move a rocket that involves storing a lot of energy in a small space should never have your total trust.

Totally agree with that!!! Even the big rockets go "Bang" occasionally. From the beginning that is the one thing all rockets have in common. Reading Rocket Fighter by Mano Zeigler right now, the Me163 had a very bad habit of going "Bang".

Mike