5 ms·

Supersonic flights over land is actually a fairly difficult problem to solve, as the noise levels are very high. This is a major reason behind why the Concorde

by Fuddh 10y ago

Supersonic flights over land is actually a fairly difficult problem to solve, as the noise levels are very high. This is a major reason behind why the Concorde only flew across the ocean. Nonetheless I did not know Boeing was lobbying against it - that kind of protectionism does indeed hinder innovation.

caf 10y ago
Concorde did actually fly over land - Braniff Airways operated it between Washington DC and Dallas Fort Worth under a short-lived, strange 'tag flight' arrangement (where the aircraft would continue on from Washington to London / Paris under BA / AF crews). This segment was sub-sonic, though.
- dingaling 10y ago
  And for each US domestic rotation each individual aircraft was reregistered onto the US N-register, and then back onto the UK or French register for the Atlantic crossing. At that time only N-reg aircraft were pemitted to operate internal commercial US flights. To simplify the process the BA Concordes were allocated unique-for-the-UK alpha-numeric registrations which could have their 'G-' prefix hidden by speed-tape: http://www.braniffpages.com/n94aa.jpg http://www.braniffpages.com/n94aa.jpg
- jrnichols 10y ago
  Here's a link to an old Braniff schedule showing the Concorde as a route out of DFW... http://www.departedflights.com/BN102879p52.html http://www.departedflights.com/BN102879p52.html
mabbo 10y ago
Apparently (can't find the article I read on it) the noise would be much less of a problem today. The magnitude of the sonic boom is relative to mass, and modern planes are being built lighter and lighter (to save on fuel). Something like a 50-seat mostly-carbon-fiber super sonic aircraft at 50,000 ft might well be perfectly fine to fly over land at Mach 2. The smaller size might also help with the problem of empty seats. As well, ideas like wings that change shape/angle for different portions of the flight could also help. Someone just needs to put down the R&D money and take the risk to build such a plane.
- Fuddh 10y ago
  I did not know this - great point! Actually being able to use simulations to a much larger extent than was possible back when Concorde was being developed must play a role in lowering the costs of building a new supersonic aircraft. I believe this is what Boom is trying to do! Let's hope they can spur more investments into this field - it would be very cool if we got to see supersonic travel again :)
  - mabbo 10y ago
    Apparently, I was wrong! While many organizations are working on reducing sonic booms, mass is not a factor.
- brian_cloutier 10y ago
  That doesn't sound reasonable. The sonic boom is caused by (I had thought) air being compressed at the front of the plane. That would mean the loudness is determined by speed and shape of the plane. The only way mass would have an effect is if the exhaust (which heavier planes presumably generate more of) contributed to the sonic boom, which doesn't sound right. I'll believe that modern planes might generate smaller sonic booms, being more efficient sounds like it's related to how you displace the air, which sounds very related to the size of the boom, but I don't believe you that mass is related.
  - mcguire 10y ago
    Not necessarily. The amount of air displaced is related to the mass of the aircraft. A heavier plane displaces more air, leading to a more energetic boom.
    - nf05papsjfVbc 10y ago
      Are you suggesting that if we have two planes of the same size and shape, the heavier one displaces more air? I can understand that objects floating on water follow that principle but that's because they are floating. Once fully suspended in water, I think the amount of water they displace is just their volume. Shouldn't it be likewise for aircrafts in the atmosphere?
capilotractor 10y ago
When I was 13, we had a math class that was scheduled at the same time the Concorde flew over the school, 35 km away from the Roissy airport. The teacher had to stop talking for 10 seconds and wait for it to fly away. This thing was loud.

by Fuddh 10y ago

caf 10y ago

Concorde did actually fly over land - Braniff Airways operated it between Washington DC and Dallas Fort Worth under a short-lived, strange 'tag flight' arrangement (where the aircraft would continue on from Washington to London / Paris under BA / AF crews). This segment was sub-sonic, though.

dingaling 10y ago
And for each US domestic rotation each individual aircraft was reregistered onto the US N-register, and then back onto the UK or French register for the Atlantic crossing. At that time only N-reg aircraft were pemitted to operate internal commercial US flights. To simplify the process the BA Concordes were allocated unique-for-the-UK alpha-numeric registrations which could have their 'G-' prefix hidden by speed-tape: http://www.braniffpages.com/n94aa.jpg http://www.braniffpages.com/n94aa.jpg
jrnichols 10y ago
Here's a link to an old Braniff schedule showing the Concorde as a route out of DFW... http://www.departedflights.com/BN102879p52.html http://www.departedflights.com/BN102879p52.html

mabbo 10y ago

Apparently (can't find the article I read on it) the noise would be much less of a problem today. The magnitude of the sonic boom is relative to mass, and modern planes are being built lighter and lighter (to save on fuel). Something like a 50-seat mostly-carbon-fiber super sonic aircraft at 50,000 ft might well be perfectly fine to fly over land at Mach 2. The smaller size might also help with the problem of empty seats. As well, ideas like wings that change shape/angle for different portions of the flight could also help. Someone just needs to put down the R&D money and take the risk to build such a plane.

Fuddh 10y ago
I did not know this - great point! Actually being able to use simulations to a much larger extent than was possible back when Concorde was being developed must play a role in lowering the costs of building a new supersonic aircraft. I believe this is what Boom is trying to do! Let's hope they can spur more investments into this field - it would be very cool if we got to see supersonic travel again :)
- mabbo 10y ago
  Apparently, I was wrong! While many organizations are working on reducing sonic booms, mass is not a factor.
brian_cloutier 10y ago
That doesn't sound reasonable. The sonic boom is caused by (I had thought) air being compressed at the front of the plane. That would mean the loudness is determined by speed and shape of the plane. The only way mass would have an effect is if the exhaust (which heavier planes presumably generate more of) contributed to the sonic boom, which doesn't sound right. I'll believe that modern planes might generate smaller sonic booms, being more efficient sounds like it's related to how you displace the air, which sounds very related to the size of the boom, but I don't believe you that mass is related.
- mcguire 10y ago
  Not necessarily. The amount of air displaced is related to the mass of the aircraft. A heavier plane displaces more air, leading to a more energetic boom.
  - nf05papsjfVbc 10y ago
    Are you suggesting that if we have two planes of the same size and shape, the heavier one displaces more air? I can understand that objects floating on water follow that principle but that's because they are floating. Once fully suspended in water, I think the amount of water they displace is just their volume. Shouldn't it be likewise for aircrafts in the atmosphere?

capilotractor 10y ago

When I was 13, we had a math class that was scheduled at the same time the Concorde flew over the school, 35 km away from the Roissy airport. The teacher had to stop talking for 10 seconds and wait for it to fly away. This thing was loud.