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The premise of Boom Technologies is that the intensity of the sonic boom can be managed by creating an aircraft with a sufficiently clever shape. I don't know
by liability 6y ago
The premise of Boom Technologies is that the intensity of the sonic boom can be managed by creating an aircraft with a sufficiently clever shape. I don't know exactly how that's meant to work, but it's this premise that they hope to demonstrate with the small-scale XB-1 in 2021.
- andi999 6y agoCan one short sell a non listed startup?
- liability 6y agoI don't think they're going to be a commercial success, but I don't really have a reason to doubt the possibility of new supersonic aircraft being quieter than older ones. Is there some particular reason to doubt this aspect of Boom's proposal?
- andi999 6y agoThe supersonic boom basically comess from the medium and nobody has been able to get rid of it. So the boom is not an engineering problem but a physics problem. Startups can solve engineering problems but rarely invent new physics (which might exist, mind you). So this new product will be limited to the same routes as concorde (plus pacific if they manage extra long haul).
- liability 6y agoThe supersonic boom comes from the interactions between the aircraft and the medium, not from the medium itself. I think it stands to reason that the properties of the boom can be manipulated by manipulating the properties of the aircraft's shape. It's not even controversial that some aircraft design elements can reduce the intensity of sonic booms, the only question is whether Boom has enough know-how to achieve the house levels they promise.
- renewiltord 6y agoYes, but you need to do it manually and know someone willing to lend you the shares. There's no exchange I know of.
- bernulli 6y agoThe key thing is that the absolute pressure rise through the shock wave isn't very high - it's just perceived as a loud boom when it is reached in a very short time. The pressure wave is ultimately caused by displacement because of the volume of the aircraft, lift, and engines. We cannot really get rid of any of these. Given enough time, a strong enough pressure pulse will steepen into the double-shock 'N-wave' (because the pressure signal is N-shaped) the sonic boom. Sonic boom mitigation then means to prevent the pressure waves from steepening into a boom before it hits the ground, e.g. by a long nose, lift distribution over a large part of the aircraft length, putting the engines on top so that their pressure wave radiates upwards, etc.
- Tossrock 6y agoUninformed speculation: I wonder if you could mitigate via a precisely out-of-phase second boom which destructively interfered with the first one? Kind of like noise cancelling headphones. Schlieren photography shows us that there are actually multiple waves being produced over the body based on where the geometry experiences sharp changes, so maybe if those were designed juuust right?
- bernulli 6y agoUnfortunately, it turns out that (for ideal gases, such as our atmosphere) a 'negative shock', i.e. a rarefaction shock, is impossible. It would violate the 2nd law of thermodynamics! And if you have multiple, subsequent shocks (one at the aircraft tip, another at the engine inlet, another at the wing, etc), the later ones will eventually catch up to the first one, resulting in the N wave we would want to avoid.