to Proposal Research Military Vertical Take-Off Aircraft Introduction Helicopters possess vertical take-off and landing capabilities; airplanes possess high velocity forward travel. Combining the two to achieve vertical take-off and landing (VTOL) aircraft is a powerful military tool now being developed. This aircraft would have the ability to hover in mid air, perhaps conducting battlefield surveillance, or gathering information on enemy troop movements in hostile areas [Mallegol, 1999]. Statement of Problem The US military seeks to develop aircraft with vertical take-off and landing capabilities, which lessen the negative effects of previous unacceptable designs. Past designs produced too much ground erosion during take-off, had hot gas recirculation problems, and were difficult to fly. [Braybrook, 2000] The goal of the military is to overcome these and other challenges with a cost effective design. Current designs need to provide sufficient jet-lift and longitudinal balance. They also must transition easily between upward and forward travel. Achieving these goals would enhance the possibilities of the US military. This would eliminate the need for a long runway for take off or landing, saving space and creating mobility never seen before in the aviation world. Military professionals envision quicker takeoffs that are also safer for the ground crew, ideas, which are not possible with conventional airplanes. VTOL aircraft can be launched from otherwise inaccessible areas allowing greater combat options. There are two main VTOL options. One is the SoloTrek XFV, a flying vehicle backpack that is strapped to the operators back. Created mainly for patrolling , scouting or searching operations, the SoloTrek is a simple solution to VTOL travel. It has a backbone that contains a four cylinder two cycle horizontally opposed piston engine that powers twin ducted fans. [Mecham, 2001] It is designed to reach a hover altitude of 8,000 ft but has an expected operating altitude of 100 ft. Transitioning from hover to forward flight is accomplished by the operator leaning forward 15-20 degrees. The ease of this transition together with the ease take off would make this aircraft especially useful in urban areas where other means of transportation are inaccessible. The other VTOL aircraft option is the airplane. Although more complex than the SoloTrek, planes provide many more capabilities and uses for the military. Two main groups are developing designs, Boeing and Lockheed Martin. Neither design is without problems, but both promise impressive technological advances. Boeing's design possesses the encouraged engineering simplicity but excessive fuel consumption in low level cruise needs to be avoided. The Lockheed Martin design uses a superior lift fan model compared to the Boeing, but its take off performance is limited by the momentum drag of the air drawn through the fans. Research must be done to determine whether or not this technology is pertinent the to effectiveness of military operations. If it is not, then the efforts and money should be
invested elsewhere. If it is, then the appropriate design must be chosen for each division of the military. Objectives I propose to analyze the available literature on military vertical take-off aircraft. I will accomplish these three goals through my research: Demonstrate why or why not vertical take-off aircraft are beneficial to the US Military; Explain major differences in aircraft designs and the resulting effects; Evaluate the designs in reference to military needs and cost of development, selecting one as the optimal choice (not sure what word to use here; want to say the most bestest one of them all). In the past each section of the military has had varying levels of interest in VTOL aircraft. The US Navy was first interested in VTOL to prevent accidents while landing airplanes on aircraft carriers. The simpler solution of modifying the aircraft carrier itself eliminated the Navy's original interest in VTOL, as it was no longer needed to improve aircraft carrier safety. Since then, the Navy periodically reconsidered adding VTOL technology to its aircraft carriers. The Navy's primary benefit of VTOL airplanes would be the increased likelihood of launching and recovering airplanes if a carrier were damaged. Military engineers found it easier and safer to stop, then land rather than land, than stop an airplane. Another benefit of VTOL in the Navy would be more flexibility during combat missions, as these planes can be launched and recovered at will. Aircraft carrier crew workload would be lessened by the use of VTOL aircraft. Despite potential benefits the Navy continues to opt not to use VTOL airplanes. The Marine Corps, however, has always shown an intense ...