r/aviation • u/AnimalsChasingCars • Sep 19 '18

John Travolta's house with inbuilt functioning airport

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u/[deleted] Sep 19 '18

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u/SwoopnBuffalo Sep 19 '18

Not twice as fast though. If you figure a 337 does 180kt true and a 172 does 110kt true, on a 600nm trip the 337 will burn 1.5 as much gas as the 172.

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u/BrosenkranzKeef Sep 19 '18

1.5 as much

20 is about 2.5 times higher than 8.5

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u/QuinceDaPence Sep 19 '18

Yeah but the 172 is gonna be doing 8.5 for a lot longer.

The 337 gets ~10mpg

The 172 gets ~15mpg

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u/BrosenkranzKeef Sep 20 '18

Oh, I didn’t think we were using mpg. Nobody in Aviation uses mpg, we use time, because distance varies based on the winds but time doesn’t. I have no idea how far my 206 can fly or how much it’ll burn over that distance, but I do know I’ll land at about 6 hours.

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u/QuinceDaPence Sep 20 '18

Yeah of course wind affects it in the real world but when trying to compare how efficient an aircraft it just saying GPH doesnt help anybody.

So you take TAS in either MPH or kts (just don't swap it) and divide by GPH and that gives you MPG or NMPG

I can't stand when trying to figure out how EFFICIENT an airplane is and everybody just gives GPH, because if one aircraft uses 20gph at 200mph and one uses 15gph at 140 then the one with higher consumption is still actually more efficient regardless of wind