Air Cannon Instructions

For KC-135 crew, midair refueling takes lots of practice

A smile creases the face of Airman Christopher Cannon as the big gray flying gas station rumbles down the runway at MacDill Air Force Base.

"I'm excited," he says as the KC-135 Stratotanker rises into the air.

Cannon, 26, has been with the Air Force for 2½ years, almost all of it as a boom operator on the Stratotanker. He has spent almost 1,000 hours in the air and refueled hundreds of aircraft, from F-16s to British Tornadoes to C-17 cargo planes.

But for Cannon, a member of the 6th Air Mobility Wing, today's flight will be something new.

He is scheduled to hook up with a venerable B-52 out of Barksdale Air Force Base and, along with the rest of the crew, practice the delicate dance of midair refueling.

"I've never refueled a B-52 before," says Cannon, an affable man with brown hair and brown eyes who hails from northeast Pennsylvania. "It's a great airplane."

Up in the cockpit, the pilot, Maj. Eric Zion and co-pilot, 1st Lt. Kendall Brown, go over charts and instructions as the tanker cruises at 286 knots to its designated rendezvous over Alexandria, La.

Zion, who's been in the Air Force for 11 years and flying tankers for the past five, has made more than 300 refueling missions.

"The biggest challenge is maintaining the right timing," he says as the tanker bounces gently through the blue sky and majestic clouds visible through the windshield. "You are flying two aircraft in close proximity."

Just by approaching so close, says Zion, the B-52 will affect how the Stratotanker flies. The big bomber will create a "bow wave," he says, causing a rush of air to push the tanker's nose down as the bomber approaches.

Given how much training and skill it takes to perform such a maneuver, Zion laughs when asked if he has ever been in danger.

"No close calls," he says.

About a half-hour before reaching the ARCT – air refueling contact time – the tanker crew gets word from Barksdale that the B-52 is running late. "Mechanical issues," Cannon says, slightly dejected.

Not uncommon for such an old aircraft.

As he waits to head to the boom pod, Cannon talks about the last time he flew into harm's way.

It was March. He was on temporary duty and he got the word to pack his bags. It wasn't until he got to the airstrip that he found out where he was headed.

"We were part of the first wave of air strikes to enforce the no-fly zone" against the regime of Libyan leader Muammar Qadaffi.

Android controlled t-shirt cannon - Hack a Day

Every year, Qualcomm hosts the “Battle of the Schools.” This year the goal was to build homemade contraptions that would be judged on how cool they are. [Doug DeCarme], [Shaver Deyerle], and [Zach Rattner] – three Qualcomm employees at Virginia Tech – built an  Android controlled t-shirt cannon for this event and ended up tying with Michigan State for first place.

The cannon is built around an Arduino Uno and a BlueSMiRF Bluetooth modem . [Doug DeCarme], the Android developer of the group, put together an app that would fire each barrel independently. The valves for the cannon are just 150 PSI inline sprinkler valves, bought from the local Home Depot. From the project breakdown, the team spent less than $150 on entire project.

From the video , we see that they’re getting some pretty good distance firing t-shirts at 160 PSI. Although we question the wisdom of using PVC as a pressure vessel holding 160 PSI, changing the PVC to a proper air reservoir wouldn’t be that hard.

Why is PVC unsafe for storing air when it is used all the time for safely transporting water and other liquids?

Water, like most liquids, is not compressible, therefore it cannot store energy. When a hydrostatic failure occurs, water is projected, but the shrapnel is not projected very far.

On the other hand, air and other gases are compressible. This can result in large amounts of stored energy. System failure could lead to a disastrous situation when this energy is released, sending shrapnel outward. Severe injury and damage can result.

PVC is susceptible to breaking – through physical damage, crushing, sudden impacts, etc. Small scratches on the outside of the pipe can turn into stress points that when combined with air pressure behind them, can lead to sudden and rapid failure – and injury.

Posted at 6:06 pm on Jul 16th, 2011 by Hackerspacer

Slightly dangerous? Yes!

..but no one is going to make a spud gun with anything else, so stop preaching this. 99% of people don’t have the capabilities or equipment to work with other materials. The danger is negligible when these things are only used a handful of times.

Hell, it’s even remote controlled, which means that they won’t need to be standing next to it if it goes off.

Posted at 6:39 pm on Jul 16th, 2011 by Slanderer

How hard is it to weld on an NPT fitting and attach a steel pressure tank that you can get for $20 – $40?

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