How to Modify a Helicopter… Without a Helicopter

Graduate student Abdullah Mamun faces a dilemma: He needs to learn how to repair a UH-60A Black Hawk without seeing the helicopter. Not only that, but he doesn’t even have a scale model to experiment on.

Mamun is one of two Ph.D. students doing aerospace research at FAU, a university without an aerospace engineering program. Under the eye of principal investigator and engineering professor Gopal Gaonkar, the team is one of three in the United States working on helicopter stability during aggressive maneuvers — the other two being Penn State and Georgia Tech.

Aggressive maneuvers include making sharp turns in the air and, specifically, making the turns quickly. These maneuvers often cause the rotor to stall, and it is up to Mamun, Gaonkar and grad student Ranjith Mohan to determine how to fix the problem — without a Black Hawk.

Step one: Enroll in more classes
Before completely submerging in the research, the team must complete three semesters of aerospace-related coursework. Gaonkar, who has worked with helicopters since 1967, teaches these required classes, such as wind turbine systems.
“I’ve always worked in the area of helicopter dynamics,” Gaonkar says. “Helicopters can do things that no other vehicle can do, [such as] vertical takeoff and emergency landing … [but] the helicopter is basically an unstable vehicle.”

However, Mamun and Mohan don’t have such an extensive background in aerospace technology. In fact, these two mechanical engineers learned about helicopters from scratch and completed their preliminary coursework last spring.

Step two: Do the math
The Army Research Office in North Carolina sent the team a packet of data consisting of a user manual, which gives the team the dimensions of the helicopter, and a computer program that they can plug data into. However, this is where the givens stop and the research begins.
“Helicopter flight involves very complicated modeling,” Mamun says. “And there is no exact solution to the problems [we are working on].”

Like with most experimentation, this project relies heavily on trial and error. In order to make progress, the team must create algorithms and compare them to the data provided by the Army.

To use the algorithm, the team must create a graph on the computer and input the proposed equation. The team also inputs the results of the tests conducted by the Army, which show up as dots on the graph. The closer the dots are to the line, the closer the team is to finding the correct equation. It may just seem like difficult — or, to be blunt, boring — math to non- scientists, but it is less harmful to make a mistake on a computer than with thousands of pounds of machinery.

From here, the team must develop their own theories about why the helicopters act the way they do. Before they can put their theories into action, though, they must fly to California and pitch their ideas to other aerospace engineers. And they’ll most likely get there via modern jet.

Step three: Explain it to others
To continue receiving funding from the Army, the team must present its progress at the NASA Ames Research Center in Palo Alto, California.
“The Army lab works closely with NASA,” Gaonkar says. “We hope to one day present our theories [about how to fix the helicopter] there.”

Penn State and Georgia Tech, both of which have aerospace engineering programs, are also working on Black Hawk helicopter stability. However, there is no guarantee that these rival schools will come up with a viable solution before FAU, since no one has managed to fix the problem yet.
“In the case of helicopters that are used in war, it requires the ability to move very fast up at sharp angles,” Mamun says. “[Right now] it’s not to the satisfactory level — there is still a big scope of improvement.”

About the helicopter:
The UH-60A Black Hawk is a utility transport helicopter. An entire 11-person, fully equipped infantry squad can be lifted in a single Black Hawk and transported faster than in previous vehicles. The helicopter can be flown in most weather conditions and its airframe is designed to progressively crush on impact to protect the people inside. Overall, it has enhanced the mobility of the Army due to dramatic improvements in troop capacity and cargo lift capability.
[Source: United States Army Homepage, www.army.mil]

How it affects you:
Helicopters are often used to transport people to and from remote locations and accident scenes. Most other aircraft need runways in order to take off and land, but a helicopter does not due to vertical takeoff.

What these terms mean / in English:
Rotor: A part that revolves in a stationary part / The spinning part on top of the helicopter

Aerospace: Space comprising the earth’s atmosphere and the space beyond / The sky and above

Algorithm: A step-by-step procedure for solving a problem or accomplishing some end, specially by a computer / A complex math equation

[Source: Merriam-Webster Dictionary, www.merriam-webster.com]