By Victor Chen, Naval Air Warfare Center Aircraft Division, Public Affairs
Five score minus one year ago today (99 to be exact), the Navy completed calibrating the first carrier-based catapult on USS North Carolina (ACR-12), after flinging a Curtiss AB-3 flying boat into the sky.
It wasn’t the first launch of an aircraft off a ship, but it was a significant jump ahead for the science of Naval Aviation.
Where does the science come into play when launching planes?
Before we continue, go ahead and give yourself a mental break with your favorite Top Gun shirtless beach volleyball replay.
Are you back? Top Gun gave us that iconic image of the energy on a carrier flight deck. But below the well-rehearsed flight deck ballet of rainbow shirts, ordnance, and aircraft, when you look through the steam-filled haze, on the deck are four supercharged steam-powered slingshots. Sailors adjust these slingshots for the type of aircraft, how much it weighs, and the desired end speed to make sure the aircrew and their multimillion-dollar, ordnance-packing “Rhino” makes it off the deck for its sortie.
Some Sailors who work on those catapults like to look at the bow as the largest double-barrelled shotgun in the Navy.
The science and experience behind our ability to do all of that safely is a gooey mixture of straight-up physics, brawny mechanical engineering, and slippery dynamic fluid flow.
The aircraft’s launch bar is connected to the catapult shuttle. If you were to go down below, you’d see the shuttle is just one part of a giant piston assembly. Built-up steam pressure in a reservoir tank sits behind the piston, ready to thrust the shuttle forward. Sailors adjust how fast and with how much force the shuttle moves using special valves that connect the steam tank and the piston. The valves open at the rate needed for just the right amount of steam pressure to drive the piston assemblies, sending the aircraft hurtling off the deck to put ordnance on target. The whole assembly stops violently as its lance slams into a vented cylinder filled with a vortex of water.
But, as Bob Dylan first told us in 1964, the times they are a-changin’.
Just a couple of weeks ago, the Navy made history by beginning to test a new kind of aircraft catapult.
Navy’s newest catapult is noticeably different. Instead of that gooey mix of hard-core mechanics and boiling water, the Electromagnetic Aircraft Launch System, or EMALS, is quiet and sleek. If it were a car, EMALS would be a Tesla.
Down in Newport News, Virginia, where the future USS Gerald R. Ford (CVN 78) is under construction, I caught up with Robert Puakea III, the lead for NAVAIR’s Carrier and Field Service Unit, which is responsible for making sure NAVAIR’s aircraft launch and recovery equipment (think catapults, arresting gear, landing lights, and even fire trucks) get installed correctly.
As NAVAIR’s resident expert at the shipyard, he has more than 34 years of experience on aircraft launch and recovery systems, including service as an enlisted Aviation Boatswain’s mate (equipment), a designer with Newport News Shipbuilding, and as a Navy civilian engineer.
“The first thing I noticed was … nothing,” Puakea said. “With steam cat launches, you hear and see the steam, you smell the heated trough cylinder lube oil, and you feel the violence of the water brake impact throughout the ship. With EMALS, all of that was gone. The shuttle just moved.”
So what is behind EMALS?
EMALS works by controlling electrical currents and adjusting magnetic fields on a huge scale, but remains small enough to fit inside an aircraft carrier.
Here are three reasons the Navy selected EMALS as the first new aircraft launch technology in more than 50 years:
- EMALS has a wider energy range, giving the Navy more flexibility as we look at what the carrier’s air wing of the future might look like and the capability to launch it all – from lightweight unmanned aircraft systems to heavier strike fighters.
- EMALS automates many maintenance and troubleshooting procedures and uses a modular architecture, which allows for easier repairs and component replacements, increasing efficiency and decreasing workload for Sailors supporting aircraft launch operations.
- EMALS is capable of launching more aircraft in a shorter period of time, with less stress on airframes, more accurate end speed control, and smoother acceleration.
The Navy’s advanced the science behind aviation a lot since Lt. Godfrey de Chevalier catapulted from USS North Carolina in 1916, completing calibration of the first aircraft catapult designed for ships.
The Curtiss AB-3 Flying Boat he flew was about 2,500 pounds and could fly about 70 mph. Today’s F/A-18E/FSuper Hornets are more than 30 times as heavy and today’s catapults can send them off the deck at about twice the AB-3’s max speed.
There are only two places on the planet (CVN 78 and the test site at Lakehurst, New Jersey) where harnessed electrons will shoot aircraft into the sky, and they both belong to the U.S. Navy. Much like USS North Carolina and her crew, when commissioned, CVN 78 will usher in a new era of naval aviation science with EMALS.