Another Hypersonic Aircraft, by Hypersonix (Australian company)

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That's pretty cool! I'm surprised they chose a conical nose cone.

I note they specify "green" hydrogen. The label "green" when applied to hydrogen usually means the hydrogen is produced from electrolysis instead of fossil methane. But it's not clear from that article alone that's what they mean. Saying "the only emissions will be water vapour" doesn't tell the whole truth about ... 🤔..."greenliness". 🤓

Cool-looking and an interesting project either way! And a good idea for a scratch-built!
 
It LOOKS cool, but will it ever fly?
Time will tell.

Hypersonic's are easy in theory, but very difficult in the real world.

I agree Funkworks! It would make a nice scratch build!
 
Rather than trying do blast your way through the atmosphere and dealing with all of the problems of heating and sonic booms, just go up and over its faster and more energy efficient. K2SO finds that design boring and un-inspired.
 
That's pretty cool! I'm surprised they chose a conical nose cone.
Me too. It has the same problem as conical soldering iron tips in that the cross-sectional area reduces according to the square of the distance. The area rapidly decreasing means there is less ability to conduct the heat from the tip away (or towards it in a soldering iron). Going to a chisel shape reduces the rate of change of area to a somewhat linear function rather than an unfriendly non-linear square function. Think about the tip vanishing to a line, rather than a point.
 
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Me too. It has the same problem as conical soldering iron tips in that the cross-sectional area reduces according to the square of the distance. The area rapidly decreasing means there is less ability to conduct the heat from the tip away (or towards it in a soldering iron). Going to a chisel shape reduces the rate of change of area to a somewhat linear function rather than an unfriendly non-linear square function. Think about the tip vanishing to a line, rather than a point.

Also, the cone's base edge is a discontinuity. At subsonic speeds, that breaks laminar flow and causes drag. I'm sure they modelled it, but I'd be curious to know if it actually provides some kind of advantage in the transonic or ultrasonic regimes. Maybe this isn't the actual shape and only a media version.
 
Me too. It has the same problem as conical soldering iron tips in that the cross-sectional area reduces according to the square of the distance. The area rapidly decreasing means there is less ability to conduct the heat from the tip away (or towards it in a soldering iron). Going to a chisel shape reduces the rate of change of area to a somewhat linear function rather than an unfriendly non-linear square function. Think about the tip vanishing to a line, rather than a point.
The square function only applies for filled structures where the whole cross section is conducting. If it is assumed, that this is a hollow structure (weight, usable space), with roughly constant wall thickness the relationship becomes linear (or at least roughly).
If the cooling mechanism is radiative, it scales with T^4. In this case, it will be dominated by local emission at the hot tip instead of conduction to colder areas despite their bigger surface area. That being said, if needed there can be in an active internal cooling loop. All these things probably behave quite different than the heat flow in a soldering tip.

Reinhard
 
The square function only applies for filled structures where the whole cross section is conducting.
It still applies to the internal volume where structures and equipment can be used to move the heat away from the skin. The available volume reduces very quickly to a point.

All these things probably behave quite different than the heat flow in a soldering tip.
True, but it is similar geometrically and also a heat flow problem. In the case of conical soldering iron tips the outer skin (iron) is worse at heat conduction than the central core which is copper. The copper core stops a significant distance behind the pointy tip. I think the heat conductivity factor difference is around 20. Difficult to drive the heat to the pointy end. For the spacecraft the problem is conducting the heat to something that will distribute the heat flux on a greater area. The very tip of the vehicle does indeed suffer the same problem as the conical soldering iron tip in that the cross sectional area available for the heat flux to flow through becomes vanishingly small at the tip.
 
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