5 ms·

Still one of the most impressive planes I know. It has to be fuelled in flight because before heat expansion closes the gaps between all metal parts, the fuel

Still one of the most impressive planes I know. It has to be fuelled in flight because before heat expansion closes the gaps between all metal parts, the fuel tanks would leak their contents. So you take off with just enough fuel to reach the tanker.

willvarfar 9y ago
Every interview with an A12 or SR71 pilot on YouTube touches on this and says they did that because of tire pressure not leaks.
- toomuchtodo 9y ago
  Do you have a source? I've checked several online sources, and they all indicate the body leaking fuel until thermal expansion took place is accurate.
  - willvarfar 9y ago
    Am on phone so can't go double checking, but I believe it was definitely explained in this one: https://m.youtube.com/watch?v=MGdxpqqsHl8 https://m.youtube.com/watch?v=MGdxpqqsHl8 (Well worth watching the whole thing!) The planes definitely leaked at low temp eg on the apron but not much at all; just a few drips. The problem was the tires were gonna burst if you aborted a takeoff with a full fuel load and had to land immediately. It was a weight problem. Murray takes about it at length and even says he has a tire at home in the garage. He also hands around other bits of the plane so people can see the honeycomb etc.
    - toomuchtodo 9y ago
      Thank you!
  - burfog 9y ago
    Two things there: 1. leaking 2. taking off without a full load of fuel It makes sense for the first to be thermal expansion issues, and the second to be tire pressure issues.
nikofeyn 9y ago
i have heard of the fuel leaking at takeoff thing, but it doesn't make sense to me why that would mean the plane would be fueled just enough to takeoff. if it leaks, it leaks. unless a full fuel tank caused a major increase in the leakage, seems to me you would just fill it up. (although i did see the less than full tank seems to be due to the weight and tire issue at takeoff explained in the other comments.)

willvarfar 9y ago

Every interview with an A12 or SR71 pilot on YouTube touches on this and says they did that because of tire pressure not leaks.

toomuchtodo 9y ago
Do you have a source? I've checked several online sources, and they all indicate the body leaking fuel until thermal expansion took place is accurate.
- willvarfar 9y ago
  Am on phone so can't go double checking, but I believe it was definitely explained in this one: https://m.youtube.com/watch?v=MGdxpqqsHl8 https://m.youtube.com/watch?v=MGdxpqqsHl8 (Well worth watching the whole thing!) The planes definitely leaked at low temp eg on the apron but not much at all; just a few drips. The problem was the tires were gonna burst if you aborted a takeoff with a full fuel load and had to land immediately. It was a weight problem. Murray takes about it at length and even says he has a tire at home in the garage. He also hands around other bits of the plane so people can see the honeycomb etc.
  - toomuchtodo 9y ago
    Thank you!
- burfog 9y ago
  Two things there: 1. leaking 2. taking off without a full load of fuel It makes sense for the first to be thermal expansion issues, and the second to be tire pressure issues.

nikofeyn 9y ago

i have heard of the fuel leaking at takeoff thing, but it doesn't make sense to me why that would mean the plane would be fueled just enough to takeoff. if it leaks, it leaks. unless a full fuel tank caused a major increase in the leakage, seems to me you would just fill it up. (although i did see the less than full tank seems to be due to the weight and tire issue at takeoff explained in the other comments.)