discussion the 'Stuff That's Just Really Interesting 'thread

[Izerous]

Bombardier just announced the Global 8000 as the 'fastest' private jet available. it has a range of up to 8000 miles and can attain speeds of up to 717mph, which is about 90% of the 767mph needed to go super sonic. interestingly, the air frame the G 8000 is built on broke supersonic speeds during testing. no word on price, but being as big as it is, no doubt absolutely ridonculous!

Bombardier claims new Global 8000 is world's fastest business jet

Bombardier has taken the covers off its new Global 8000 business jet, which the company claims is the world’s fastest and longest-range production business jet, combining a luxury cabin with a top speed of 623 knots (716 mph, 1,152 km/h) and a range of 8,000 nm (9,200 miles, 14,816).

newatlas.com

I recall a documentary about the concorde and it touched on airplane speeds and it touched on reasons why no passenger planes have been supersonic or stay well under supersonic speeds even though we are capable of that technology. Ignoring cost of design and all that fuel usage of being anywhere near the sonic barrier is hugely increased. Stay well below or stay well above and fuel usage is way more efficient. But a certain range around the sonic barrier causes a huge spike in fuel usage.

Id assume if I'm remembering that right planes like this are likely as fast as things will get for quite a while unless someone starts selling fully supersonic private jets.

(Someone please correct me if I'm wrong on what I remember from that documenary)

 

[moocow]

Don't know which one you are referring to but US SST program involved running supersonic tests with military aircraft over a city. Basically the result of that trial led to banning supersonic flights over land except by military aircraft. You can't do that either in Canada. Right now the efforts are to reduce the boom. Once that's figured out there will be people ordering the jets for private use for sure.

Quesst

Oklahoma City sonic boom tests - Wikipedia

en.wikipedia.org

 

[Shadowmeph]

I always loved Harriers , I also think the old warthogs are cool also they are the tanks of the sky. not that I agree with Killing

 

[Izerous]

I always loved Harriers , I also think the old warthogs are cool also they are the tanks of the sky. not that I agree with Killing

Growing up playing games like A-10 cuba and a bunch of very similar games the warthog will always be a standout. Video clips of the guns going full blast are always interesting.

 

[Sagath]

I recall a documentary about the concorde and it touched on airplane speeds and it touched on reasons why no passenger planes have been supersonic or stay well under supersonic speeds even though we are capable of that technology. Ignoring cost of design and all that fuel usage of being anywhere near the sonic barrier is hugely increased. Stay well below or stay well above and fuel usage is way more efficient. But a certain range around the sonic barrier causes a huge spike in fuel usage.

Id assume if I'm remembering that right planes like this are likely as fast as things will get for quite a while unless someone starts selling fully supersonic private jets.

(Someone please correct me if I'm wrong on what I remember from that documenary)

I'd be remiss to mention that I'm not a physicist, but from my rudimentary University days in Physics class I cant see how going faster would lessen fuel consumption, ever.

Simply put; Faster means hotter and more drag, to compensate for drag (given no other changes) you have to add more energy (in this case, fuel). You cant really mitigate those things by going faster again...

 

[Izerous]

I couldn't find the original documentary that I recalled watching but searching for it basically the drag right around mach 1 spikes and then slowly drops off some as you exceed the sound barrier. Super sonic is still worse than subsonic but there is an area where the drag is so bad you want to ensure your cruising speeds are outside of the spike. Short version is it has to do with how the wave pressure forms on the wings etc when your right at the mach 1 range and that changes as you exceed mach 1.

Searching "drag divergence mach number" brings up a lot of papers on it like this one.

https://www3.nd.edu/~atassi/Teaching/ame%2060639/Notes/compressible.pdf

 

[Sagath]

I couldn't find the original documentary that I recalled watching but searching for it basically the drag right around mach 1 spikes and then slowly drops off some as you exceed the sound barrier. Super sonic is still worse than subsonic but there is an area where the drag is so bad you want to ensure your cruising speeds are outside of the spike. Short version is it has to do with how the wave pressure forms on the wings etc when your right at the mach 1 range and that changes as you exceed mach 1.

Searching "drag divergence mach number" brings up a lot of papers on it like this one.

https://www3.nd.edu/~atassi/Teaching/ame%2060639/Notes/compressible.pdf

Ah, sorry I read the comment more that 'fuel efficiency increases above mach relative to below mach', not relative to flying at exactly Mach vs not-mach.

 

[moocow]

To be honest, I'm really interested in this thing but with floats option.

WACO YMF-5 | Brand New Land or Amphibious Biplane

The WACO YMF-5 is the Perfect Combination of Classic and Contemporary. Based on 1930's Design, this Brand New Open-Cockpit Biplane is Equipped with Modern Technology and Safety Features. Powered by a 300 Horsepower Jacobs Radial Engine and Optional Amphibious Floats.

www.wacoaircraft.com

 

[Marzipan]

@Izerous the fuel consumption and big issues with heat, are the largest roadblocks to hypersonic flight.

the fuel spike between sub and super isn't surprising. my sister was a speed demon on the Coq between Kamloops n the LML. she usually went around 150kph and then on a dare drove the limit... she was floored at how much less gas she burned and over a few more trips at how the travel time difference was negligible. this was in a RAM 1500 w/ HEMI.

 

[Izerous]

A Ram basically has the aerodynamics of a brick to boot. My dad going between Ft Mac and Edmonton his corvette was the most fuel efficient out of anything he owned. Highway cruising speeds it was basically idling along.

I have had 3 vehicles max out around 180-185 (sunfire, 2004 Outlander premodifications, 4L frontier) but not on open roads in traffic... I did do some really really really dumb things in that sunfire though that would have probably been justification for loosing my license on the spot.

Heat wasn't something I really thought about for supersonic travel but it makes a lot of sense that it would become a huge issue when dealing with such high drag values.