Sonic booms – Concorde exempt?

[SlipStream77]

navier_stokes said:

As has been discussed, mass is irrelevant. Only additional lift, which is required as a bi-product of increased weight, is proportional to shock intensity.

If you have two identical wings flying through the same medium - one made of lead and the other of aluminium, the resulting aerodynamics, and thus shock structure would be identical (ignoring surface finish and aeroelastic effects).

Edited by navier_stokes on Tuesday 20th March 21:09

What about gravitational effects?

[navier_stokes]

SlipStream77 said:

navier_stokes said:

As has been discussed, mass is irrelevant. Only additional lift, which is required as a bi-product of increased weight, is proportional to shock intensity.

If you have two identical wings flying through the same medium - one made of lead and the other of aluminium, the resulting aerodynamics, and thus shock structure would be identical (ignoring surface finish and aeroelastic effects).

Edited by navier_stokes on Tuesday 20th March 21:09

What about gravitational effects?

They are both fixed in place within a wind tunnel

[Le TVR]

So Dryden also says that measured overpressure is proportional to the mass of the aircraft. They have published the measured results. Are they wrong too?

[navier_stokes]

Le TVR said:

So Dryden also says that measured overpressure is proportional to the mass of the aircraft. They have published the measured results. Are they wrong too?

Where do they say it is directly proportional to weight? It says it is a factor that can influence it... and I'm saying this is indirectly through the additional lift required.

Where are the measured results?

[dr_gn]

Le TVR said:

So Dryden also says that measured overpressure is proportional to the mass of the aircraft. They have published the measured results. Are they wrong too?

No, but mass is still not the term to use to define lift - it's lift that potentially makes the difference. OK mass and lift generated are propably closely linked in most aircraft cases, but apparently not for a general 'magnitude' type equation - which is what I was getting at initially.

[Le TVR]

I haven't said it was directly proportional to mass..

Look at what Boeing say too:

http://www.faa.gov/about/office_org/headquarters_o...

[dr_gn]

Le TVR said:

I haven't said it was directly proportional to mass..

Look at what Boeing say too:

http://www.faa.gov/about/office_org/headquarters_o...

Pretty sure you could substitute "weight" for "size" in any of those slides.

[Le TVR]

navier_stokes said:

Where do they say it is directly proportional to weight? It says it is a factor that can influence it... and I'm saying this is indirectly through the additional lift required.

Where are the measured results?

NASA tech paper 1820,
Langley Research Centre 1981

I can send you a copy if you can't find it.