Tuesday, February 8, 2011

Aircraft flying for 5 years without refuelling - The DARPA way

Some time back I had watched a documentary by National Geographic " America`s Secret Weapons", which essentially featured DARPA in seemingly insane , but credible pursuits...robots attached to soldiers, diving speed enhancing equipment, and RPG ( Rocket Propelled Grenades) avoidance system for Humvees etc.
 But of the many futuristic projects DARPA is engaged in, the one which caught my eye was that of designing and flying aircraft that could stay aloft in the sky for  5 Years !!!
Now, the project has come to fruit, if Boeing`s latest contract with DARPA for $89 million is anything to go by. Named as "Project Vulture" the aircraft will be a solar powered , flying in the stratosphere.The electricity stored by the fuel cells will power the electric motors for the propellers and the systems.DARPA believes that the Vulture will combine positive aspects of both satellites and aircraft in providing a strategic advantage to the operator, also in terms of the cost involved.
As always, there is room for skepticism as to its efficacy. If the Vulture is to derive solar power, it would have to  fly constantly over the clouds , facing the sun. The "Zephyr" was a predecessor , which used solar power to fly non stop 2 weeks. Herein lies the catch :  Zephyr flew in Arizona, which is just about 30 degrees above the equator.The solar power is much higher in the equator and tropics compared to the northern and southern latitudes. Otherwise the accompanying loss of solar power would easily ground the aircraft in these regions and other wintry areas. If the Vulture is to overcome this, it would require truly phenomenal fuel cell conversion efficiencies than those available today, which stands at about 35-40 %.
                                                        The Zephyr`s Flight
But there is sense in the US Military`s requirements, most of which would be in the arid ,sunny  regions of the middle east and Asia; where the Vulture can perform well in spite of the current constraints.The present contract to Boeing would initially fly a prototype non stop for 30 days, for testing . But the project duration stumps me..... would DARPA do a test to actually check if the thing can stay aloft and kiss the skies for 5 years?Even if these geniuses do pull it off, It would be a tragic comedy if it fails after .. say.. 3 or 3.5 years in perpetual flight.
So the next question... test it AGAIN?Or better still , the easier option- change the program objectives to suit a 3 year flight.....
Now THAT.. is food for thought :-).


Anonymous said...

I think it would b a modified version of NASA'S Helios.....

Arvind T.M. said...

Yes.. but it was a more experimental aircraft, for civil purposes, communication equipment etc. Not for Military purpose, which is the Vulture- with higher endurance and more critical mission requirements.

The Imperfectionist said...

y do they actually need an aircraft which can stay at sky for 5 long years?!?!?1

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