It Only Looks Fat

Dean Sigler Sustainable Aviation 2 Comments

Aviation Week reports on the inner workings of Boeing’s Phantom Eye HALE (High Altitude Long Endurance) unmanned aerial vehicle.  The craft, now being tested at NASA Dryden Flight Test Center at Edwards Air Force Base, has a rotund character that shows form does follow function.

Boeing's Phantom Eye HALE reveals its inner beauty

Wrapping two eight-foot diameter hydrogen tanks in a low-drag pod and boom style fuselage, the “bulbous” but aerodynamic shape seems at variance with its sailplane-like 150-foot wings.  Overall, the design’s unlikely look conceals its purpose as well as its enormous fuel tanks.

According to Aviation Week, “Boeing’s objective is a production HALE UAV [unmanned aerial vehicle] with an endurance of 10 days, which would enable it to remain on station for four days at 10,000nm [nautical miles] range, or six days at 6,000nm. Three such air vehicles would be able to maintain continuous surveillance anywhere on Earth, [Boeing Phantom Works’ Keith] Monteith says, for a dramatic reduction in cost compared with today’s 24- to 36h-endurance UAVs.”

With hydrogen’s high energy density, the twin 2.3-liter Ford engines will run for days on end, where a similar effort powered by more conventional fuels would lack such endurance and weigh a great deal more.  The lean 7,500 pound empty weight and 9,350 pound takeoff weight show the low mass that even the full hydrogen tanks add.  To further save weight and costs, the aircraft takes off on a dolly (that stays earthbound) and lands on skids.

Engines have three-stage turbochargers to compress the air at high altitudes and a gearbox to reduce the speed of the four-bladed propellers.  Flight tests are scheduled to begin soon.

Comments 2

  1. I love Boeing’s commitment to UAV hydrogen… but to me, this competition with Aerovironment to get military contracts is preventing serious application of H2 and its approach to storage. I spoke with those who built the tanks for this craft, and see nothing really new on the storage/insulation side… EVERYBODY knows the 21st century future of aviation is going electric (especially Boeing)… and the future fuel is H2.. (what else is there? Bio-oil from algae?). And, as everybody knew for the last 40 years, the REAL problem is the approach to H2 storage… Doing this ICE-conventional motor-propeller approach is NOT going to push the art… Boeing/Phantom/St Louis certainly must have something a lot better in their deep (black?) pockets to deal with H2 fuel for UAV… I do not fault Boeing, but most likely it is the mission objective that might be the real problem here… A much different approach might be a LOT more viable for the next 40 years…. namely a VTOL strategy that does NOT necessitate to be flown from some base in the Nevada deserts to get to station “anywhere in the world”…THAT mission requirement was made necessary most likely by the issues of using a new and exotic fuel in a desert war zone. This WAS a good idea back when we were ready to spend 4 trillion dollars doing wars in the near east. With the whole world in bankruptcy court… we need aviation technologies that could become exportable consumer products and not mere extensions of wars that nolonger have popular support financially. YES UAV, YES HYDROGEN, YES BOEING, but NO to the mission statement. When budgets cuts come deeply, a better approach to H2 storage is likely to be developed.

  2. This aircraft is now visible in Google Earth and Maps. Go to the northern edge of the tarmac at Edwards AFB and you’ll see it sitting there, although it nearly blends with the pavement. It’s just to the west of the ‘315’ marker on the compass rose. I was struggling to identify it until I came across this blog post.

    (Editor’s note: Thank you for this. I’m headed for Google Maps shortly.)

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