Links to NASA Website with in-depth calculations on the flight of a paper rocket
What are some tips and tricks for using the launcher with a large group of people?
Lesson plans for Elementary School
Lesson Plans for Middle School
The launcher operates entirely pneumatically, meaning it uses only air pressure. The pressure is provided by the kinetic energy used to drive the pump, and is converted to potenial energy in the form of air pressure within the tank. Once the blue part of the slide valve is moved to the "Launch" position, that potential energy air pressure is converted back into kinetic energy, launching the rocket off the launch tube. For a more detailed view of how this works, click on the cross section image to the left or on the text above, or download the PDF here.
I'm having trouble pressurizing the launcher, what do I do?
Most likely, there is a leak between the threaded components. This typically occurs if the joints have not had enough Teflon tape applied (4-5 wraps should be enough) or the joint is not tightened enough. To find exactly where a launcher is leaking, loosen the wing nuts and slide the tank out from the wooden base. Remove the launch tube, and submerge the pneumatic assembly (slide valve, orange tube, QEV/Tank/overpressure valve) underwater in a sink or tub. Slowly pressurize as normal, and look for any bubbles escaping. Once you find the leak, disassemble the joint, remove the previous Teflon tape, apply 4-5 new wraps and retighten. Double check for leaks using the same procedure.
Orange hose may not be fully seated. If the above submersion procedure shows air leaking our around the orange tubing, it is likely that it was not inserted far enough into the fitting. Try pushing the tubing harder into the fitting. If it is fully seated but still leaking, it can be removed, trimmed slightly and reinserted. To remove the tubing from the right angle fitting on the inlet of the QEV, push inward on the blue ring on the elbow fitting and pull outward on the orange tubing. To remove the tubing from the slide valve, push inward on the chrome ring while pulling outward on the tubing. Trim 1/2" [12mm] from the end of the tubing with a sharp blade. Reinsert the tubing back into the fitting about 3/8" [10mm] or so. Double check for leaks using the same procedure.
Quick Exhaust Valve (QEV) not properly sealing. This is usually due to some debris at the seal between the top face of the diaphragm and the outlet leading to the launch tube. This will present as a rocket slowly sliding up off the launch tube before the slide valve is actuated. There may also be a slight "honking" sound, as demonstrated in this video (with an old version of the launcher). Sometimes, pieces of Teflon tape can reach this surface, or if something is dropped down the launch tube it can interfere with this seal. See below for steps to clean the QEV. We also offer a replacement o-ring seal for the QEV.
Worn out o-rings in the Slide Valve. We have tested our launchers thousands of times (thanks to visitors to SEE Science Center) so we know they are durable. However, things don't last forever. If you find a leak between the blue slide valve and the central body of the slide valve, that means the o-rings are worn out. We offer replacement o-rings.
How do I disassemble and clean the QEV?
If needed you can take the QEV apart carefully and make sure it’s super clean inside. See pictures below for details:
1. So, you don’t need a vise to open the QEV. as you already have the launcher fully assembled, you can use the aluminum tank clamped in the wooden base as a vise when you unscrew the QEV. Angle the launch tube horizontal, so when you are loosening the cap, you are pushing downward toward the floor, like this using an adjustable wrench, or large pliers:
2. Once the cap is loose, fully unscrew the cap and check the seal. It should look like this image, or the seal may be clear silicone:
3. You can now remove the diaphragm from the body of the valve and inspect the seat - the two areas circled in green. Check for anything across the surface of this inner gray circle, or on the flat face of the rubber diaphragm. I usually put the diaphragm in the removed cap, as it is somewhat greasy with petroleum jelly. It should look like this when clean:
4. Reinstall the diaphragm in the body of the valve in the orientation shown below; the open side of the "cup seal" facing the launch tube:
5. Now thread the cap back on to the body by hand - don't forget the spring! It drops into the center of the hole in the cap and pushes on the completely flat face of the diaphragm. Loosen the wingnut on the U bolt and flip the launch tube to the opposite side of the launcher, and tighten the wing nut in the opposite fashion as you loosened it. Now you can tighten the cap while again pushing downward toward the floor. You can again use an adjustable wrench or large pliers like this:
It takes longer to explain this than it really is to do it.
If this does not work, or if you have difficulty, just let us know and we’ll get you a replacement valve ASAP or send you a replacement kit. We would just ask that you send us the first kit back so we can inspect it and find the root cause of the problem so we can learn from this.
How do I replace the O-rings in the slide valve?
It’s fairly easy to replace the O-rings in the slide valve, but this is only needed if you have verified that this is where the leak is occurring. The O-rings on the slide valve should last many thousands of cycles.
1. Start by removing the schrader valve from the body of the slide valve. An optional Big Red Button (BRB) is shown here:
2. Next, use a small flat blade screwdriver to remove the retaining ring from the body of the slide valve. Use caution not to stab yourself with the screwdriver.
3. Slide the blue section off of the valve body:
4. Remove the old O-rings. I found that a corkscrew is quite effective at removing them. Something that is not too pointy works best. This is showing the Schrader valve end O-ring being removed.
5. There is an O-ring in each end of the blue slider. Repeat the process for removing the O-ring from the launcher side of the blue slider.
6. Apply some petroleum jelly to the new O-rings and install them into the original grooves. Note when reinstalling the blue slider, it must be installed with the relieved end as shown here:
7. Ensure that the blue slider slides partway over the large hex on the body of the slide valve:
8. Reinstall the retaining ring, it goes on easier that it comes off. Apply new Teflon tape to the pipe threads, and reinstall the schrader valve or BRB button onto the slide valve, and you are all set to launch again!
How do I connect my air rocket launcher directly to an air compressor?
It’s super simple to connect your Air Rocket Launcher directly to an air compressor. Instead of attaching the Schrader valve/Check Valve to the “Launch” side of the slide valve, screw in a 1/4″ NPT Male Quick Connect Compressor Fitting. Set your compressor output pressure to about 100 psi.
Slide valve back towards the compressor to launch and then forward towards the launcher recharge. Launcher will be ready immediately for the next launch.
Due to the wide variety of air compressor fittings available, we do not offer these quick connect adapters for sale. They are available at most hardware stores, auto parts stores, Lowes & Home Depot.
You guys are awesome! How can I help you grow?
We want to be in as many science museum shops as possible. Do you know someone that works in a museum? Share our website with them, show them your rocket and tag them in videos of your rocket you share on social media.
Invite friends to see the launch of your rocket, loan your launcher to your local school or better yet, help a teacher do a launch day with their class.
Share your launches on Facebook, Instagram, Youtube, Twitter and Reddit. Tag us in the shares!
Like and share our pages on as many social media venues as possible!
Help by volunteering at a local Maker Faire using one of our kits, or help us at one of the larger faires that we attend. In most cases, you will get free admittance if you volunteer for a few hours. Contact us if you are interested by going to the upper right menu, hoover on “About Us” the drag your cursor down to “Contact Us.”
NASA Links on Air Rockets
Here is a link to a fantastic NASA website with in-depth calculations for the flight of a compressed air rocket - be sure to click through all the links:
Intro:
https://www.grc.nasa.gov/www/k-12/rocket/rktstomp.html
Flight:
https://www.grc.nasa.gov/www/k-12/rocket/rktsflght.html
Launch Calculations:
https://www.grc.nasa.gov/www/k-12/rocket/rktslaunch.html
Ballistic Calculations:
https://www.grc.nasa.gov/www/k-12/rocket/ballflght.html
Equations including Air Resistance:
https://www.grc.nasa.gov/www/k-12/rocket/flteqs.html
Terminal Velocity:
https://www.grc.nasa.gov/www/k-12/rocket/termvr.html
Rocket Modeler:
Using the Launcher with Large Groups
With all of the Maker Faires that we have done over the years, we have learned a few things the hard way. Here is a list of tips and tricks when working with kids of all ages:
We recommend arranging a table or two as shown on the left, with the launcher positioned so that there is a large portion of a table downrange. This prevents people from getting too close to the launcher.
For younger students, we recommend the BRB (Big Red Button) adapter, which is literally a big red button that is easy to smack to launch the rocket.
Our standard templates were developed with large crowds in mind - no scrap (the entire paper is used), standard sheet of 8.5" x 11" paper, all the instructions are printed right on the template, and it is held together with almost any type of tape. The rocketeers can keep thier rockets afterward.
The NASA/ULA/SpaceX templates are quicker to build, especially without a nosecone. They are very lightweight and even work indoors in a large gym. If foam noses are added, they fly 3X or more higher, due to the added aerodynamics and mass.
We also have plans for a packing tape cutter to significantly speed up the making of a NASA/ULA/SpaceX template. Contact us if needed.
To speed up the paper & tape rocket production process, mandrels are recommended. Mandrels are simply ≈12" long pieces of 1/2" PVC pipe with the ends slightly rounded so they are not sharp. We sell mandrels cut to length already, but they are quick to DIY as well.
Consider pre-making and reusing foam rockets: https://makezine.com/projects/high-pressure-foam-rocket/
Fins can quickly be made from only tape with the same process of folding and sticking as used on our standard sticker fins. Experiment with the number of fins, size, shape, angled (rifled), placement along the body, etc.
Instead of a foam nose, wine bottle corks are excellent nosecones. If you want to get fancy, you can make a crude lathe to add a cone to the cork nose by gripping a screw in the chuck of a drill screwing on the cork (like a corkscrew) and sanding to the desired shape with coarse sandpaper.
Small superballs also work well as nosecones, just seal the end of the body tube with tape, and tape the ball on top of that. The center of mass is so far forward on this that fins aren't necessary.
Consider connecting to a small air compressor. A low cost portable air compressor works great, and they are available very inexpensively from Harbor Freight, Here:
or Here:
Contact us if you are considering using our launcher as an exhibit at a Maker Faire, we would like to help out.
High School Lesson Plans
PDF Work Sheet: Rocket_Project_Student_Instructions
The template below can be used to document the altitude a rocket achieves by using a standard protractor, string and a small weight along with a tape measure. Using some simple trigonometry, the altitude of the rocket can be measured.
PDF Lab Sheet: lab_writeup_template
Special thanks to Cynthia Bruins and Freedom High School and The Patriot Jet Team Foundation for allowing us to use these documents.
To see how well this project worked for Freedom High School, take a look at the local news report: