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USWaterRockets.com - Research & Development Report - March 1, 2014 - Water Rocket Chase Camera Project.
   

Water Rocket Chase Camera Project

Anyone who has seen our website USWaterRockets.com or has subscribed to our YouTube Channel already knows that our team has placed a focus on building water rockets for the purpose of recording interesting aerial photographs and movies. Ever since we strapped a digital video camera onto a water rocket over 10 years ago, we have been fascinated with recording onboard video. We are always on the lookout for new twists of the onboard camera concept that take advantage of the unique advantages that water powered rocket provide.

We've always tried to break new ground with unique and entertaining experiments, which include: The first water rocket with HD video, the innovative use of camera booms to record experimental payloads, the use of wide angle lens adapters as macro lenses for onboard experiments, the use of multiple onboard cameras, and of course having flown rocket with onboard cameras nearly double the altitude of any other water rocket (with or without cameras).

Carbon Fiber X-12 Water Rocket with Onboard HD Camera.   HD Camera Aft Onboard View from the X-10 Water Rocket.

Some of our ideas were our efforts to replicate camera work inspired by prior work done by NASA and Armadillo Aerospace, which we tried to emulate with our hobby. However, we also wanted to try and invent a camera system for water rockets that had never been seen before. We wanted to do something completely unique for Water Rockets to show off their capability and perhaps generate more interest in the sport.

Seven cameras used to set World Record for maximum Number of Cameras flown on a Water Rocket.   Aerial View of Water Rocket Launch taken using a Remote Controlled Quadrotor.

As early as 2003, we were experimenting with ways to get outside views of our water rocket. Back then we had been flying a camera inside a payload compartment that was meant to separate from the pressure vessel at apogee. We wanted to try and come up with an original idea similar to that, which would record the entire rocket for the entire flight, rather than just the descent of the pressure vessel.

This image was taken from a payload section camera bay that was designed to parachute as a separate unit. The pressure vessel of the X-9 Water Rocket is visible below.   The X-7 Water Rocket is seen from the camera and payload bay as it separates at apogee in this frame capture of a video reocrded in the fall of 2003.

The initial idea we came up with was to place a camera on a long boom looking down on the rocket from above to get a top down view of the rocket as it flies. The length of the boom combined with a wide angle lens would create a unique perspective of the flight that as far as we could tell had never been attempted before.

Concept art for the External Camera Pod.   Test fitting the Camera Pod to a Water Rocket.

For the actual build, we started out with an 808 Keychain Type #16 HD camera with a wide angle lens. But since our primary launch site employs a body of water for the landing area, we had to design a waterproof camera pod to contain the camera so that it would not get wet at splashdown.

HD 808 Keychain Camera Type #16 with Wide angle Lens used in the Camera Pod.  Water Rocket heading for splashdown in Galway Lake.  All Electronics on our rockets must be water tight to prevent damage from landing in water.

The camera pod was constructed from a pair of 500ml soda bottles, using the bottle shrinking technique developed in our splicing tutorial, except the bottles were taped together with electrical tape instead of being glued. This way they could be taken apart to operate the internal camera. A small disk of PET plastic sheeting was glued into the neck of the bottle to form the window where the camera looks out.

500mL Bottles were used to construct the outer shell for waterproofing the Camera Pod.  The bottles were modified using the methods in our Slip Joint Bottle Splicing Tutorial so that one bottle will slide inside the other.  The bottles fit together much like our Slip joint Splices, except in thise case we do not glue them permanently together.

We used some scraps of corriflute material to make a frame to position the camera inside the camera pod. The frame for the camera was trimmed to fit inside the pod, and adjusted until the camera was centered in the window. We also fabricated some carbon fiber rods which we used as struts to hold the camera above the nosecone of the rocket.

Corriflute makes a strong and lightweight frame to hold the camera in place inside the Camera Pod.  The camera positioning frame we made from Corriflute.  Carbon Fiber Struts were made to put some distance between the camera pod and the top of the rocket.

To make the camera pod and boom structure portable between various rockets, A cylindrical section of a soda bottle was attached to the struts so that the whole system could be placed over the nose of a rocket and taped in place. The top of the ring was slightly shrunken so that it would prevent the rig from sliding too far down the nosecone.

An adapter was made from another bottle which would allow the Camera Pod assembly to slip over the nosecone of several different rockets.   The adapter ring was slightly shrunken with heat to create a ridge which would prevent it from sliding down under acceleration.

The bottle sections were then painted in bright colors, and the inside of the pod and the areas surrounding the camera window were painted flat black to reduce reflections on the inside of the window from spoiling the view of the camera.

The components were painted in bright colors to make them easy to see from far away.  The interior of the Camra Pod was painted flat Black to prevent reflections on the interior window spoiling the video.  After the paint cured, we began to assemble the Camera Pod.

We test fit the camera pod on top of a rocket and it seemed like it would work well. Test fitting with the camera installed allowed us to adjust the position of the camera perfectly, and do some test video to make sure that the camera would get a good view of the rocket. If the view was blocked too much there would be no point in going further. Once the testing was complete. All we needed was a nice launch day to try it out.

The assembled Camera Pod.   Test fitting the completed Camera Pod to the nosecone of a Water Rocket.

While we were waiting for good weather, we came across a humorous video on YouTube, which depicted a young child pulling out a loose Deciduous tooth using a string tied to a pyro rocket. Watching this video gave us an idea for a unique way to modify our camera pod to make it even more unique. Instead of pushing the camera pod on a boom in front of the rocket, we thought it would be more interesting to tow the camera pod behind the rocket using a tow line.

Another view of the completed Camera Pod.   Concept Art showing the proposed improvements to the Camera Pod.

The changes we made were to add a second camera to the front of the camera pod (creating the dual camera pod), and then to attach some mason line to the front. The opposite end of the mason line was then attached to the back of our water rocket. The adapter ring was repurposed as a ring fin on the back of the pod.

This arrangement is probably only practical with a water rocket, since a pyro rocket strong enough to tow a camera pod would likely burn the tow line or chase camera, and the smoke from the pyro engine would probably ruin any recordings can camera made anyhow.

Adding a second Camera to the Chase Camera Pod.   Slots in the Corriflute hold the cameras in place.

The dual camera pod (now called the "Chase Camera Pod") was then tested to make sure it could float and was water tight after splashdown. We conducted these tests by tossing the chase camera pod in the water and seeing what would happen. The pod was observed to float nicely but the fin section tilted the pod about 45 degrees from horizontal. Observing the chase camera pod floating this way gave us one more idea to make this concept truly unique. Why not launch it from a floating position in the water? We decided to give it a try, and set up for our first test.

Testing the Chase Camera Pod for leaks.   Concept art for the final Chase Camera Design.

The results from the first test flight were mixed. Apparently, the sea launch idea was a bit too radical because the friction from the water was just too high, and it pulled the ring fin off and broke the tow line. The only thing we learned from the flight was that the camera system could survive a lot of violence.

Preparing the Chase Camera for Sea Launch Test Flight #1.  The Tow Line is fixed to the nozzle of the Water Rocket.  Test Launch #1.

We decided to launch the next test flight from dry land. We also decided that the rear camera was not recording video that we couldn't already get from a rear camera on the rocket itself, so we took it off, making the chase camera pod lighter and easier to lift. These changes should improve the changes of a successful launch.

Test Launch #2 was flown from dry land, since the Sea Launch idea did not pan out.   Care must be taken to insure the Tow Line does not tangle with anything on the launch system.

As we were setting up for the second test flight, clouds rolled in and the lighting turned very poor. Since we had just finished preparing for launch, we decided to fly in spite of the poor light. Even in the bad lighting when we looked at the chase camera video, we could tell that we were on to something really amazing looking. We had just recorded the very first water rocket selfie. We just needed to try again with better lighting conditions.

Test Launch #2 captures the first Water Rocket Selfie.   The Parachute Deploy is seen from outside the Water Rocket.

The Third test launch proved the concept was a winner. We had a great launch on a bright sunny day with excellent lighting conditions, and the onboard and chase camera videos did not disappoint. The rocket was visible from the chase camera video for the entire flight right up to the parachute deploy, where the chase camera passed by the decelerating rocket until the tow line finally went taught again. The concept was a complete success.

Test Launch #3 was on a nice sunny day.  From the chase Camera, the water column is brightly lit by the sun.  Capturing the parachute deploy from an external camera may make debugging of new parachute deployment systems much easier.

We then decided to conduct more test flights to try and determine how to tweak the system to get longer and larger views of the rocket in flight. The first change we decided to make was to shorten the tow line by about 3 feet to collect some data regarding how the tow line length would affect the chase camera video. We thought it would bring the camera closer to the rocket and it would see more action that way.

Test Launch #4 used a shortened Tow Line to get closer to the Rocket.   Test Launch #4 appeared to be flawless.

Apparently, the short line was a bad idea because the camera pod appeared damaged when it was recovered. The struts had broken loose and were barely holding the ring fin on. We were anxious to see what happened in the onboard video. When we reviewed the onboard chase camera video we could see right away something was amiss because the colors in the video were completely distorted.

Aft facing Onboard Camera on the Water Rocket shows the Chase Camera following close behind.   Something went wrong, and the colors of the Chase Camera video were distorted.

Review of the slow motion video revealed what happened. As the chase camera took off, it was towed directly through the water jet coming out of the rocket. At a combined impact speed of over 200MPH, the shock must have been very strong and damaged the camera. Still photographs taken from the ground show damage to the chase camera fin struts, proving a serious impact happened at launch, and did not happen at splashdown. Another interesting bit of evidence was discovered during frame by frame analysis of the chase camera video. Prior to and just after launch, the video is fine, but the colors go bad just a fraction of a second after launch. Looking closely at the last good frame in the video shows a very close view of the water column directly ahead, and some of the pixels at the bottom of the image are showing the color corruption. We concluded this was proof positive of the water column impact being the cause of the camera damage.

The final frame of good video from the chase camera shows the water column about to impact the camera. The lower pixels were captured just as the water impacted and they are distorted.   Damage to the fin struts is visible from the ground as the rocket parachutes back, which proves that the incident happened when the rocket launched.

Fortunately, we were able to determine the problem with the camera was confined to the light sensor module, and we were able to repair it with a replacement part. Since the chase camera pod was badly damaged by the accident, we decided to build a second generation version of the pod, which would be improved and would be less likely to be damaged by the water column. Future articles will detail the second phase of the project. Check out the video report linked below and see the video version of this article and don't forget to favorite our website so you can check back for the follow up articles documenting how we perfected the chase camera.

Chase Camera Video:

Update: 06/23/2014
In the first part of this project, we discovered that the Chase Camera Pod could be pulled into the Water Thrust Stream coming from the rocket, and that the combined speed of the chase camera and the water created a huge impact force which could tear the Chase Camera Pod apart, and damage the camera inside. In the second part of the project, we attempted to make modifications which would prevent this damage in the future.

Crashing into the water column on the second flight did serious damage to the Chase Camera Pod.   Crashing into the Water Column on the second flight destroyed the 808 camera image sensor, so we repleced the sensor with a new one.

Our new idea for the Chase Camera Pod was to shrink it to the smallest prectical size that would fit our 808 Camera and reduce the mass of the Pod as much as possible. Making the Pod as small as possible would reduce the chances of impact, and also reduce the impact area, hopefully minimizing damages. Reducing the weight as much as possible would lower the momentum of the chase camera, which would allow it to deflect if impacting the thrust column, instead of smashing through it. This would further help reduce the force of any impact and therefore reduce any damage resulting from the strike.

We discovered that the 808 camera would fit snugly inside of a plastic Easter Egg, with the lens protruding through a hole in the egg, it would easily be sealed water tight with a rubberized sealer. For stability, we made a small set of fins cut from corriflute material that were shaped to interlock together. A leftover piece of Carbon Fiber Rod was used to join the egg to the fins, and the new Lightweight Camera Pod was born.

A Plastic Easter Egg proved to the just the right size to make a smaller Chase Camera Pod.  Corriflute fins were made and notched to slide together forming a perfectly aligned fin set.  The completed Mark II Water Rocket Chase Camera.

We tried various launch angles for the Water Rocket and for the Camera Pod relative to the launch direction of the Water Rocket to try and find how best to eliminate the crash into the water column, but we were able to see there were still some impacts in the Chase Camera views, but it seems like our new design was able to withstand the hits without damage, so it was a success.

The New Chase Camera Pod can be seen here ready for a flight.   The new smaller and lighter Chase Camera Pod is shown here being towed by the launching Water Rocket.

The onboard Chase Camera video views turned out very impressive. We were able to catch the parachute deploying almost completely in most of the launches. Since these launches were also test launches for our totally new Radial Deploy system, we were happy to see how well it worked from a new perspective.

Exterior Chase Camera view of a Water Rocket in mid-flight.   Chase Camera view of the Water Rocket Radial Parachute System deploying.

Watch the video embedded below to see the incredible footage we were able to capture during the initial flights of the 2nd generation Chase Camera Pod!

Chase Camera Video Part 2:

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