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We know The government wants to ween us off of fossil fuels. How many Kwh’s will the battery packs have to be rated for, on this 21,000 mph plane?
The ecological point is a good one but fossil fuels aren’t used for high speeds. For Mach 5+ you are using something like a hydrogen scramjet.

Scramjets theoretical limit is in the 20,000‘s mph range, which is probably the basis of the original metaphor.
 

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Scramjets do not work well in slow speeds and in populated areas.
So for take off you need like a turbofan (compressor) jet, then at higher speed swap to the Scramjet to get you up around 100,000 feet then kick in the Lox/Hyrda... rocket's to bust out of innerspace.
 

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Helmet to keep the grey matter in.
Boots for how deep it's getting in here.
 

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My great uncle was a lead engineer at Boeing on the SST and the 707 conversion to US Airforce KC-135's. We had a few chats when I was younger about the engine air intakes of the SST to cool the super heated air.

The 707 lived on a lot longer than most know. Started in 1957-58 It remained in production until 1991, with a total of 1,010 being built. John Trovolta donated one of the last ones by Quantas Air, N707JT
 

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Scramjets do not work well in slow speeds and in populated areas...
True, and ramjets somewhere in the middle.

Plus if anybody has been around a sonic boom - they are a problem on their own.
Concorde had to get out over the sea before they could let rip, and fast movers have to get permission in normal circumstances/
 

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My great uncle was a lead engineer at Boeing on the SST and the 707 conversion to US Airforce KC-135's. We had a few chats when I was younger about the engine air intakes of the SST to cool the super heated air.
Cool :)
budum, tish

The precoolers on the SABRE do something like 1,830 ° down to −240 °, in a hundredth of a second!

Linking back to one of Mikey Ms threads, the high intake temp is due to compression.
 

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The ecological point is a good one but fossil fuels aren’t used for high speeds. For Mach 5+ you are using something like a hydrogen scramjet.

Scramjets theoretical limit is in the 20,000‘s mph range, which is probably the basis of the original metaphor.
well, with a turbocharger and some nitrous we might get a couple more miles per hour / hay dave,,, wanna project?
 

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SR71 could fly over land at Mach+ due to sound dissipation at altitude. By the time the sonic boom reaches the ground the wave is too spred out and we hear nothing.
 

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As a kid, I lived directly under the take-off path of these things - Vulcans. It was cold war era, and the flew 24/7.
One would take off, one land every hour or so.
They were so low I could see the hexagons of the wheel nuts! Don't think elfansafety will allow that much noise now.
 

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well, with a turbocharger and some nitrous we might get a couple more miles per hour / hay dave,,, wanna project?
Lets put a Turbo and some nitrous on your Zero.
 
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So what do you think will happen when you inject nitrous into the battery of that Zero?
 
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So what do you think will happen when you inject nitrous into the battery of that Zero?
About the same as installing new sparkplugs and air filter.
 
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As a kid, I lived directly under the take-off path of these things - Vulcans...
Me too. Father was RAF fire & rescue.
Vulcan noise was unmistakeable, all the V-force aircraft were monsters.

Also E E Lightnings doing QRA intercept scramble on full 4 stage reheat, a noise you hear through your internal organs :)

Glory days when brit aircraft led the world.

Me and my brother used to sneak up to the ground attack firing range, but that was later, mostly Jaguars and Phantoms screaming in off the sea overhead at roof top height. Got the dressing down of a lifetime when our mother found our collection of ordnance casings :)
surprised I can hear anything these days.
 

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didja ever wonder how you slept at nite with all that racket? not when you were young! when you were young, you could sleep thru sex! (course , you never got the chance)
 

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SR71 could fly over land at Mach+ due to sound dissipation at altitude. By the time the sonic boom reaches the ground the wave is too spred out and we hear nothing.
Definitely. Concorde had a significantly bigger boom - but you’ll already know there is more to that story (political shenanigans).

For those that don’t: US govt/FAA banned civilian supersonic flights over any US land at any altitude from ‘73 onwards.
This knee-capped the big advantage of the brit/French Concorde, trans Atlantic routes were its mainstay.
The SST project Dave mentioned was the US attempt to catch up with Concorde but it didn’t reach production (a shame because it was advanced in many ways), so the playing field got a bit of a tilt instead :( and Concorde was never allowed to reach its full potential.

physics/technology is only half the battle
 
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