This past Sunday the group gathered at the home of the industrious (and illustrious) Stewart Spies, KB9LM to do some brainstorming, run some tests, and most importantly to enjoy some delicious grub together.  Oh, and gadgets.  Always new and fun gadgets!

Stage 1: Behold! The Stretchinator Demo

We started the session with Stewart demonstrating The Stretchinator™, his aptly named and turns out, reliably accurate, invention for stretching balloons.

The Stretchinator is an assemblage of custom software, hardware and physical infrastructure all built and devised by Stewart Spies, KB9LM. The frame is primarily constructed with PVC pipe and wood. It acts in part as a frame to keep the balloon stable and largely immobile, but also serves as a mount for the gravitational acceleration sensor. This sensor arm, which allows for pitch rotation, is attached to one of the PVC pipes that stands perpendicular to the ground. Simply put, when the arm is parallel to the ground, the sensor’s gravitational acceleration reading will equal 0.

An Arduino controls the input of the hardware with an aquarium pump, the trusty inflator. As the balloon is filled with air, the sensor arm will slowly rotate upwards. When gravitational acceleration reaches zero, the Arduino will then shut the aquarium pump off and no further inflation can occur.

Stage 2: OMNOMNOM

With The Stretchinator doing its stretchinating best, we took a break to feast on some yummy subs and sides courtesy of Cary and homemade guac by Stewart. We finished off with a few plates of homemade and store bought cookies that somehow traversed to the end of the table where our younger NIBBBers were sitting. Hmmmmm… anyways, back to stretching!

Stage 1.5: Behold! The Stretchinator Demo… CONTINUES!!

Stewart uses a laser range finder to confirm The Stretchinator’s calculation of the diameter of the balloon, which in this case should be just about 32 inches. The transparent Yokohama balloons are at an advantage over the mylar SAG balloons in this sense, as the LRF can cast a laser from through the Yokohama to check The Stretchinator’s accuracy.

The results:

LRF : 31.875 inches
Diameter: 31.83 inches
Circumference: 99.996 inches

Say whaaaaaaat!? Nice work Stewart! Fortunately we were able to spare a few moments to congratulate Stewart on the success of The Stretchinator.

Stage 3: Testing makes Besting

The third item on our agenda, after The Stretchinator Demo and the all-important Eating of Cookies, was to test out sealing mechanisms for the balloons. For this step we used an Impulse Heat Sealer that, while purchased new, resembled a giant office stapler from the 50s. Typically, used to seal polyethylene and polypropylene bags, we had more diabolical plans for it: to try to achieve a secure seal at our balloons’ inflation points.

The SAG balloons and Yokohama valved balloons are self-sealing, meaning that when at full altitude, they will automatically seal themselves. Because we launch the pre-stretched balloons, partially inflated, below full altitude, sealing them before they go up is mission critical to ensure no gas escapes. This is where the heat sealer comes in.

Our objective was to test if the sealer could adequately seal the balloons. If the heat sealer is set at too high a temperature, the seal could destroy the material and create a hole. If the sealer is set too low, then a seal cannot be made. We were trying to determine what the goldilocks zone was, and if one was even in existence.

We started off by testing sealing balloon material alone using scraps cut from each type of balloon. The sealer made quick work of both mylar and polyethylene. Then we tried to seal the actual balloon’s valves. The SAG balloons have a problematic paint lining on the interior on the valve, which we determined was unsealable. A few potential solutions were thrown around, such as removing the paint with acetone, aka nail polish remover, or just leaving them unsealed, as Stewart pointed out that those balloons had performed quite well. After filling the balloons and before launch, we had been placing a small piece of either Kapton or 3M Shipping tape over the valve to prevent the gas from leaking. The Yokohama requires a nylon washer at the end of the valve opening held by tape to secure the tracker solar panel package.

Deflating doesn’t have to be bad

Somewhere during the testing, Ken had to leave so he and Stewart deflated the pre-stretched and ready-for-launch SAG balloon (thank you, The Stretchinator!). Using a Dyson hand vacuum and a weak seal with tubing inserted into the valve, Stewart literally vacuumed the air out of the balloon so it could be safely transported to Ken’s home. The process had a watching-the-paint-dry quality.

Wrapping up

With a few minutes left before everyone needed to leave, Jim revealed the new solar panel that he is developing. He also unveiled the new weather sensor package developed by Todd McKinney KN4TPG from the University of Alabama in Huntsville https://www.picoballoonarchive.org/home. We’ll post more on the weather sensor in a future post, so Stay Tuned!

Cary sent each of us home with new and very attractive rose gold-colored mylar SAG orb balloons for us to practice on so we didn’t have to leave empty-handed.

For more information – please visit us at NIBBB.org!

Until next time – happy Pico-ing!

73,
Janet KD9WVO & Cal KD9WNU