Jet A, a common fuel for airliners weights 6.8 lbs per gallon. Not sure how much the hydrogen will weigh. It may have something to do with temperature and pressure but my guess is, it will be a lot less.
This could affect a number of things regarding a flight.
A good thing might be the aircraft will be able to carry a larger useful load. More people, baggage and freight.
Something else to consider is the load factors a plane will be subject to without the weight of fuel the plane was designed to carry. A 747-400 carries 380,000 lbs of fuel in the wings when full. That weight figures into the speeds it can safely fly at in turbulent air. During severe turbulence the plane must slow down to protect the structure of the plane from breaking or over stressing. The wing is designed to produce a certain amount of lift and no more. Higher speeds mean more lift which can cause damage so need to slow down. The weight of fuel increases the stall speed of the wing which means the stall will protect the wing by reducing lift to protect the structure at a higher speed. Without the extra weight to help produce a stall the plane will have to slow down even more.
Prolly no big deal, just fly slower. Or… add ballast. Sure. Lets add 100,000 lbs of dead weight to the flight. That will go over like a lead balloon. Or shorten the wings. That might be the simplest solution. A stub wing 747. Instead of 211 feet, figure about 100 feet.
I’m guessing H powered commercial airliners won’t look anything like what we’re used to seeing. They might be more of a lifting body type aircraft with much shorter stub wings. Kind of Bernoulli design. Bernoulli designed a beautiful lifting body airplane after WWII for the Navy but the Pentagon (Army-Airforce) rejected it because they didn’t want the Navy to have a superior design large aircraft. All blue prints were to be destroyed and it was never to be spoken of again. Our Government at work. A plywood prototype sits at the Bradley Air Museum in Connecticut as our only reminder.
Then there’s other loading considerations which I have no idea about. A plane designed to fly on hydrogen will be quite remarkable and depending on the cost of fuel, will make operators lots of cash. Maybe reduce ticket prices a little.
Then the storage tanks will need to be designed and fitted. Fan jet engines? I have no idea. Prolly another redesign. I guess we’re stuck with jet A for a while.
1/10th of a volt to go before the engineers have to start thinking about crunching the numbers. When the metrics are worked out showing the potential profit, the engineers might have to work a little overtime. Let the salivation begin.
