Monday, December 13, 2010

Tornado Intercept Vehicle, TIV

This is the Tornado Intercept Vehicle Mk II.

  • Owned and operated by IMAX filmographer (and all-around nice guy) Sean Casey.
  • Gross vehicle weight: 8.75 Tons
  • Powerplant: 6.7 liter Cummins turbodiesel, 625HP
  • Driven Axles: 3 (10 wheel drive, each differentially locked)
  • Range: 750 miles (92 gallon petrol capacity)
  • 1 1/2 inch thick laminated, tempered, bulletproof glass
  • 1/8 inch steel plate armor
  • Hydraulic side, front, and rear armor plating slides and folds down during tornado intercept to prevent aerodynamic lift
  • 360 degree rotating IMAX camera turret
  • Data-collecting retractable instrumentation mast

Sean and his crew chase with Dr. Josh Wurman and the Center for Severe Weather Research (not to mention the Discovery Channel), and will be participating in the partially NSF funded Project VORTEX II in just a few months. Sean's mission is to drive this juggernaut right into the heart of a tornado while filming IMAX footage out of the turret atop the vehicle. He's had several successful tornado intercepts so far, but he's yet to get "the shot" that drives him to do what he does. Considering that from the moment you press "on", it takes a 50-pound-plus IMAX camera only three minutes to blow through all of its film (at the cost of around $60 per second), he's definitely a man who thinks big. Additionally, the ginormous retractable turret mounted on the back of the tank is not the world's coolest RC antenna -- it is, in fact, an array of weather instruments designed to sample windspeed, atmospheric pressure, and the like.

This photo was shot just east of Kearney, Nebraska on May 29, 2008. The storm in the background struck Kearney with an EF-2 tornado roughly 5 minutes before this was taken.

Tank-Like Tripod
The TIV is essentially a large, mobile, armored tripod for an IMAX camera. Its purpose is to allow filmmakers to record footage from very close to -- or even inside of -- a tornado.

The TIV was originally a Ford F450 pickup truck. Its transformation into the TIV took three months of 7-day-a-week work. After stripping it down to its engine and chassis, Casey created a new frame and body out of steel, which uses:

  • 1/4" steel plate floors
  • A skeleton of 1/4" steel tubing and I-beams
  • 1/8" steel plates welded to the skeleton
Photo courtesy George Kourounis
The TIV uses a Ford F-450’s dashboard, steering and transmission.

Tires need to be accessible, yet protected from debris, so a hinged 1/8" steel flap covers each wheel well. Each of the four doors features a double layer of 1/8" steel plate. When closed, the doors lock into place with heavy steel bolts.

The TIV's side windows are 1/2" Lexan resin, a very strong plastic. For better visibility, its windshield is a scratch-resistant tempered glass and Lexan laminate.

The TIV’s side windows.

Since the TIV's purpose is to provide a safe spot for filming, it has a special military-style turret to house the IMAX camera. The turret spins 360° on 3" steel bearings, allowing the crew to shoot footage in any direction. The TIV also has two hatches for smaller format cameras.

Portable Weather Station
Since it can survive very high winds and hail, the TIV provides a good opportunity to collect tornado data. Inside the TIV are a variety of meteorological instruments, including:
  • A blade anemometer, which measures wind speed and force in one dimension
  • A sonic anemometer, which also measures wind speed and force, but in three dimensions
  • Two global positioning system (GPS) units
  • Tools for measuring temperature, pressure and humidity
The completed TIV with rotating turret.

Including its skeleton and frame, the TIV weighs almost 14,000 pounds. In spite of all this weight, it can reach up to 90 mph.

In the next section, we will look at the equipment inside the TIV.

The TIV, after the addition of the IMAX camera turret, parked beside two Doppler on Wheels units.

Another weather research tool, the Doppler on Wheels (DOW), also uses the same instruments in addition to a mobile Doppler radar. The DOW, however, must stay between two and eight miles away from a tornado. Since the TIV houses the same instruments as the DOW, scientists can combine their data to create a more complete picture of the life of a tornado.

Now, let's look at what happens when the TIV finds a tornado.

Chasing a Tornado
What happens when the TIV chases a tornado? That depends on whether Casey and his team are working with other chasers or independently. The first step is always research. All storm chasers must determine where tornadoes are likely to form and which approach to the storm will give them the best view while keeping them out of the most dangerous parts of the storm.

Recently, Casey has worked with Dr. Joshua Werman of the Center for Severe Weather Research (CSWR). The CSWR uses the DOWs and other equipment to study tornadoes. Members of the CSWR team analyze data about the storm and help decide where to deploy the TIV [ref]. When working with the CSWR, the TIV collects data up to the edge of the debris cloud, not into the tornado itself.

The Dimmitt Tornado, south of Dimmitt Texas. Photographed as part of project VORTEX.

However, Casey designed and built the TIV with the goal of getting footage of a tornado approaching and then hitting the IMAX camera. In order to do this, he positions the TIV in the path of a tornado in a low-lying area. Then, the team films the tornado from within the TIV turret. Casey designed the TIV to withstand 200 mph winds, which accounts for about 75 percent of the tornadoes that form in the United States. This, and careful attention to the progression of the storm, reduces the likelihood of damage or destruction.

Eventually, footage from the TIV's expeditions will appear in an IMAX film about tornadoes called "Tornado Alley."

For more information about the TIV, tornadoes and tornado chasing, check out the links

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