It's in the tubes !
Well, I sent it out to Apple today, (with 6.767 as default density in the lb/USg unit...).
The review process is at least 7 days, so I'm hoping it will be available to you all in about a week...
look for "Jet Fueling" in the AppStore...
And, smallfry, I think it will help your "little brain" !
regards