Medium Altitude Endurance study conducted by Center for Naval Analysis
The main criteria CNA posited for a MAE UAV appropriate for shipboard ops :
• 24 hours on station at 500 mmi
• Takeoff weight under 3000 pounds
• Extremely short takeoff and landing (ESTOL) for minimal impact to flight deck operations
• 300 pound payload capability
• Mechanical simplicity
The CNA study
In 1999 CNA performed a comparative analysis of four shipboard ops concept UAVs: (i) fixed-wing UAV, (ii) STOVL tilt-rotor, (iii) low disc-loading helicopter UAV, and (iv) freewing tilt-body UAV. Preliminary conclusions about their relative merits are listed in this table, and led to a more rigorous study, portions of which we excerpt, below:
Low Disc-Loading Helo
A 2-stroke diesel, fixed-wing UAV would have the range and endurance required, but would not be easily integrated into carrier operations.
A V/STOL UAV, such as the tilt-rotor, could be better integrated into flight deck operations but severely compromises range and endurance.
Sensitive to turbulence, especially wake turbulence downwind of superstructure during landing ops.
The only air vehicle concept that seems to be able to (in theory) satisfy these objectives is the Freewing, tilt-body concept.