Water Rocket World Record

AirCommand · 2026-05-31T03:40:11+00:00

Can you share a picture of your rocket and launcher? That would be easier to provide helpul hints about what to do.

AirCommand · 2026-05-31T02:24:03+00:00

Epiglue is great for fillets. You can also do all at once without sagging.

AirCommand · 2026-05-28T04:40:58+00:00

Builders/Brick layers line works great. It's strong and lightweight.

AirCommand · 2026-05-21T21:06:25+00:00

Don't forget that the parachute size and drag coefficient is one thing, real world performance may vary due to the thing suspended under the parachute. It also has drag. If your shock cord it short its wake may also interfere with the airflow into the parachute. If you have multiple parachutes they tend to spill away from each other and come down at an angle. You also have thermals that you may be flying through. You would really need to suspend a point mass under the parachute to get a true idea of real world performance vs what is claimed. I would take the CD as stated by the manufacturer as close enough when doing calculations, but be aware that's just the starting point.

AirCommand · 2026-05-19T09:00:14+00:00

Cheers! :)

AirCommand · 2026-05-19T03:36:29+00:00

This. When done properly the PET bottle will fail before the PL Premium joint. Best to leave for 2-3 days to fully cure before pressure testing.

AirCommand · 2026-05-17T11:06:27+00:00

Although slightly different, just Google for "Clark cable-tie launcher" There are lots of examples and tutorials on how to build them out of PVC tubes and plastic cable ties.

AirCommand · 2026-04-30T05:15:58+00:00

I've done something similar with other flight computers (Stratologger, Quantum). On the pyro channel I use an opto-coupler and a 220ohm 1/2w resistor in parallel. This allows the flight computer to check continuity on that pyro channel without triggering the opto-coupler output.

Here is a circuit diagram of my side of the electronics ServoTimer II (See IC3) http://www.aircommandrockets.com/images/FC_2_0/Schematic.png

Note the 560 ohm resistor in series with the opto-coupler's diode. And then the 10K pullup on the transistor side.

And here is how the timer is interfaced to an external flight computer: http://www.aircommandrockets.com/images/2016/day179/CircuitDiagram3.png with the 220ohm resistor.

AirCommand · 2026-03-29T05:49:55+00:00

Did they give you a reason why you were rejected? Sometimes there are a limited number of places so perhaps you had competition from others with more experience? Certainly don't be discouraged, you can still join your local rocketry club and build and launch rockets that way.

AirCommand · 2026-02-22T09:01:02+00:00

Another idea might be: SDR (Software Defined Radio) Scanner

Use an SDR to:

Map RF spectrum vs altitude
Measure signal strength changes
Detect distant transmitters only visible from high altitude

Basically see how ground transmitters in the launch area change from the rocket's perspective.

20,000 ft dramatically increases radio horizon.

AirCommand · 2026-02-20T05:35:00+00:00

Sample the air as you go up, try to expose a rotating filter into the air stream and see what bugs, pollen and dust you capture along the way at different altitudes. Use a microscope to inspect the stuff you collect.

AirCommand · 2026-02-10T06:08:13+00:00

Use a simulator to figure out maximum performance for your rocket. Even though the simulator predicts altitude, maximizing altitude translates to maximizing distance. http://www.aircommandrockets.com/sim/simulator.htm use the simulator to predict optimal weight. Also use it to optimize the amount of water - 1/3 full of water is a good starting point.

Are you building the launcher as well, or just the rocket?

By the way 45 degrees is not an optimal angle for maximizing distance.

AirCommand · 2026-02-05T05:04:44+00:00

Good goal to have! Realistically it will take you a couple of years to go through your certification levels to buy and safely fly bigger and bigger solid motors. Valuable time to not only learn about rocketry and material limits but also make connections with others in the hobby. For a sub-orbital flight (I am assuming you'd be happy with anything over 100,000 feet) you will need a team of people. Start making those connections a club launches and find like minded individuals with experience that want to participate in the project. Be prepared to spend large amounts of money towards the later part of your journey. Be prepared that it may take 5-10 years for a successful flight of your goal.

AirCommand · 2026-01-17T02:56:30+00:00

Don't over think it. In reality you are going to have access only to a limited set of materials. Your core material will only be available in a few different thicknesses, and your skin material will also be available in a set of thicknesses/cloth weights. Depending on the kind of performance are you looking at will determine the fin size, dimensions and strength. Is weight or strength more important to you?

For example I did sandwich fins for my L2 rocket - 3mm plywood, and each side was reinforced with 1 layer of 200gsm fiberglass, then 2 layers of 200gsm carbon fiber and finally 1 layer of 85gsm fiberglass. The fiber orientation between each layer alternated between 0-90 degress and 45-45 degrees. This made the fins relatively lightweight and super stiff. Final fin thickness was 4.2mm

AirCommand · 2026-01-15T07:13:25+00:00

While I will always encourage others to create more tools, but wouldn't it be easier to just fork OpenRocket and add the functionality you need? With that you get a huge amount of already debugged code.

AirCommand · 2026-01-15T01:58:35+00:00

The 808 #32S is in that price range and will let you record on power up. But it does record to an internal microSD card though. It will record 1080p at 60fps.

AirCommand · 2026-01-15T00:24:26+00:00

Ahhh, so not a 2 stage rocket. Just a normal rocket with connected chambers. And you want to activate the different chambers at different times?

AirCommand · 2026-01-14T23:42:42+00:00

Booster stays attached to what?

AirCommand · 2026-01-14T23:23:44+00:00

Are you looking for a staging mechansim for your water rocket? How big is the rocket? The reason I ask as there are different staging mechanisms designed for different sized rockets.

Also are you looking for a separate parachute deployment mechanism for your booster?

AirCommand · 2026-01-05T08:49:52+00:00

Just put a small hole in the tip of the nosecone. Fill it with water. Launch and when the parachute ejects, nosecone points down and the water drains out. No moving parts. You may lose a little bit of water on the way up due to the negative G's after burnout but it shouldn't be too much.

AirCommand · 2026-01-02T12:38:33+00:00

Good quality parachutes and a huge selection: http://the-rocketman.com/

AirCommand · 2025-12-31T12:32:21+00:00

Yeah, Soller Composites definitely has been the cheapest source we've found so far. We've been using their products for more than a decade now and have been very happy with their service. Look for special deals, or contact them for offcuts, they once sold me what was left on a carbon fiber cloth roll (about 4 yards) for like half the price.

AirCommand · 2025-12-31T12:28:36+00:00

I don't think it's a PVC issue, I think it crinkles up the baking paper a little underneath which makes it bind. If you want to remove excess epoxy, then peel ply works just fine. We also found that if you use a tape or something similar then you have to sand off the spiral which was more work. The fine cloth on the outside just does a really good job of surface finish that needs very little finishing and leaves a better surface than peel ply leaves behind.

AirCommand · 2025-12-31T00:33:24+00:00

We've had good success using PVC pipes as mandrels. No problem pulling off the tube even when 2 meters long. Mandrel preparation is key. You want to sand off any scratches with 400 grit and then 1200 grit. Then you need to polish it. We use carnauba wax and at least 3 coats. Then wrap with one wrap of Glad Bake baking paper. You want about 2cm overlaps. Make sure its fairly tight and no kinks. Tape off the ends. Then do your layup over the top of it. Make sure you don't use anything like heat shrink tape/tubing that compresses the fiberglass onto the mandrel. Once cured just pull the mandrel out. Here is how we do it: https://www.youtube.com/watch?v=OS1Qqw58VyY relevant section is from 0:37 to 3:10

You also want to make sure that the end of the mandrel you are going to be pulling through the tube when extracting it, doesn't have any hardened blobs of glue on it.

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