The Navy N Class blimp was powered by 2 Wright R-1300 Cyclone 7 radial engines and was able to cross the Atlantic and back again without refueling. How many gallons of fuel did it carry for a maximum range cruise? The information is needed for a ton mile/gallon efficiency calculation.

  • $\begingroup$ Wikipedia says 200 hours endurance, and two R-1300s running at 50% power are going to use about 360 lb/hr (800 hp x .45 lb/hp/hr for air cooled piston engine), or about 60 US gal/hr. For 200 hrs endurance this would require... yikes... 12,000 gallons. Maybe max endurance is dialed back even more, and the 200 hrs comes from a 40% power setting. In any case, it's gonna have to have upwards of 10000 gal on board to run that many hours. Hope someone's able to find an actual number from a specification somewhere. $\endgroup$ – John K Feb 9 '19 at 21:16
  • $\begingroup$ @John K it's a start. They may have "sailed" it with prevailing winds on one engine. The Graf Zeppelin could lift around 190,000 lbs. So 70,000 lbs minus 20000 lbs crew, provisions and equipment leaves 50,000 lbs, or around 7500 gallons fuel. $\endgroup$ – Robert DiGiovanni Feb 10 '19 at 0:17
  • $\begingroup$ Well you would have to figure any range number would be based on still air and we're talking about a time aloft anyway in this case. The GZ was much bigger no? $\endgroup$ – John K Feb 10 '19 at 4:08
  • $\begingroup$ The 785 foot Akron carried 20700 gallons of fuel. There is good published info on these. $\endgroup$ – Robert DiGiovanni Feb 10 '19 at 8:33
  • $\begingroup$ @John K, will work with Akron and Macon data. Thanks for helping me dig these out. Would think the Cyclones on the N Class probably ran at a much lower RPM to get 60 knots than they would for a cruising airplane. $\endgroup$ – Robert DiGiovanni Feb 10 '19 at 12:22

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