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60 Minutes goes 'Boom'

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60 Minutes goes 'Boom'

Old 22nd Nov 2021, 10:34
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60 Minutes goes 'Boom'

One fact check please from Sunday nights segment on Boom Supersonic.

In the introduction to the piece, the correspondent said: "most of today's jetliners actually fly more slowly than they did 20 or 30 years ago to save fuel."
Really? I would think new and more efficient engine design and improvements in wing aerodynamics would be more accurate than saying planes are flying slower.

Comments welcomed from the rest of the segment.

The proof-of-concept single seat test bed is essentially complete and "will fly sometime in 2022" and the first paying passenger commercial flights are planned by "the end of 2029"

Editor-in-chief of Air Current, Jon Ostrower estimates $15 to $20 billion to bring the project to fruition and went on to say that Boeing spent the same on their last sub-sonic airframe without specifying which one he was referring to but I gather the 787? Blake Scholl, founder/CEO says he'll pull it off for $7 to $8 billion, on top of the $300 million raised thus far.

Two of the many small hurdles to overcome are a promise to run on 100% sustainable fuel and Rolls Royce has yet to come up with a powerplant. Apparently not enough to dissuade United from ordering 15.

One large hurdle to overcome is what to do about the boom. Nasa stated that they're looking to fly the X-59, also sometime in 2022, to further research into reducing that boom to a small thump in order to allow routine commercial supersonic overland flight.
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Old 22nd Nov 2021, 10:43
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400 business jets went to the Glasgow summit. Now they can fly even faster to save the world faster. Powered by green fuel, sure.
It's funny how private jets, private space flights and going supersonic are no factor for the super rich that earn money by us all going green and having to buy their electric cars, copper and lithium mine products, small nuke power plants and such. Travesty.
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Old 22nd Nov 2021, 11:01
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The 60 Minutes segment had nothing to do with business jets, Bozo's space jaunts, Musk's Tesla's, lithium mining or micro nuclear power plants.

Let's focus on the topic, alright?
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Old 22nd Nov 2021, 11:57
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Less Hair

Where can I buy a small nuke power plant? It’d certainly beat the hell out of a few solar panels on the garage!
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Old 22nd Nov 2021, 12:18
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https://www.terrapower.com/
https://www.rolls-royce.com/media/ou....aspx#overview
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Old 22nd Nov 2021, 12:55
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Less Hair

Did you not know that aviation has a miniscule contribution to global CO2 compared to surface transport, industry and electrical generation?
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Old 22nd Nov 2021, 12:56
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SpyPilot

In the introduction to the piece, the correspondent said: "most of today's jetliners actually fly more slowly than they did 20 or 30 years ago to save fuel."
Really? I would think new and more efficient engine design and improvements in wing aerodynamics would be more accurate than saying planes are flying slower.


Yes, really.

MIT: Why Hasn't Commercial Air Travel Gotten Any Faster Since the 1960s?
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Old 22nd Nov 2021, 12:56
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Dunno, hard to quantify in these days where cruise speeds and levels are managed to generally minimize cost per flying hour….which means more than just fuel enters into the equation.

This is all hand waving, rough impression stuff but from what I experienced over the years:
The 747 batted along pretty darned quickly,
The earlier big twins were slower, for the 777-200, maybe, generally .02 or .o3 Mach slower than the 744 ish/thereabouts in the cruise.
The 777-300 things started to speed up a bit again but not quite to 744 speeds.
Got the impression certainly the 380 and maybe the 787 could rattle along at 747 speeds…

In response to DRs point I was merely commenting on the last 30 years, he / the article are absolutely right that 60 years back some airliners cruised at what by modern standards would be regarded as Mach numbers..for example the Convair 880
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Old 22nd Nov 2021, 13:04
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The speed of today is coming from going point to point at the time needed not from cruising at higher speeds. This is why I don't see the final business case for some Boom passenger plane with limited range needing to earn it's eight billon development cost.
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Old 22nd Nov 2021, 13:30
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Re flying slower:

probably true if you look at the average cruising speed in 1990 - but then again there were more aircraft with more wing sweep as a proportion of airliners back then. Majority of airliners in 1990 were obviously designed in the 60s and built in the 70s and 80s.

In 2020, with the massive growth in aviation since the 1990s, the overwhelming majority of the airline fleet are based on aircraft designs conceived post 70s oil crisis and built post millenium.

The transonic regime is increasingly unfriendly in an economic sense as you close in on Mach 1.




The Citation X gives a few clues as to the requirements for operating in this flight regime.



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Old 22nd Nov 2021, 14:17
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HOVIS

I am sure most on PPRuNe are aware of this fact. It´s the 'leading by example' or rather the lack of it which annoys the general public.
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Old 22nd Nov 2021, 15:02
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I think it is fair to say that a quest for efficiency has reduced true airspeeds for the "average" commercial airliner, in two obvious ways.

1) as referenced above by DavidReidUK's link, higher and higher jet bypass ratios, which can have a higher peak efficiency, but at a lower TAS, and

2) higher and higher cruise altitudes (Mach .88 is "slower" at FL420 than at FL320 - 505 kt vs. 515 kt, assuming otherwise constant conditions - but burns less fuel)

"Workhorse" 707s and 727s used to zip along at 490-510 kts TAS. Current A320 family members or the 737s are engineered with a different goal in mind.
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Old 22nd Nov 2021, 15:16
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Statistics are all in how they’re presented. In the last 30 years there have been about 4500 ERJ and CRJ airliners built. That has certainly slowed down the average airplane speed. There’s no reason to operate a half full 737 to the middle of no where when when you have RJs that can do the route a bit slower but much cheaper.
Cost Index in the 747 goes from 0-600. I’ve seen days when the release says 45 and days when it says 600. On those go fast days days it’s all great until ATC says we're following an RJ doing .74 so slow to .73.
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Old 22nd Nov 2021, 17:31
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Less Hair

Concorde didn't pay back its development cost, but when BA decided to ignore that and fly it anyway, there was no lack of customers willing to pay (usually someone else's money) to go to and fro between LHR and JFK in 3 hours instead of 7½ to 8 hours. I didn't see the 60 Minutes segment but I daresay the Boom developers might think they can improve the economics.
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Old 22nd Nov 2021, 19:04
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Unfortunately Concorde was no sound business case after oil went up and Boom won't be either. Concorde had not one but two industrial countries wanting to fund it plus an engine. Boom is investor funded only. I wish them the best but I don't see it happening. The small test aircraft is far from their final triple engine mini Concorde. How many would they need to sell to break even at eight billion plus development costs?
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Old 22nd Nov 2021, 19:25
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Anyone else remember the Boeing "Sonic Cruiser"? It would have cruised at Mach 0.95+, with costs/mile equivalent to a 767 - so about 20% faster than the Mach ~0.82 design cruise speed of the 767. After a lot of initial excitement, the whole concept was dropped because the airlines decided they'd really rather have an aircraft that flew about the same speed as a 767 but with ~15-20% lower per mile costs. There simply are not a lot of people who are willing and able to spend a large premium to get there a few hours sooner. Biz jets are a little different - the people who fly on biz jets generally are not too worried about costs (if they were they'd fly commercial), although like Less Hair I question if the potential market is large enough to even begin to justify the investment.

As for cruise speeds, although there were a few outliers in the early jet age that went faster (which were commercial flops), most longer range jets cruise in the Mach 0.80 to 0.85 range and it's been that way since the '60's. The 747 was originally designed to cruise at 0.87, but the fuel burn went up so fast between 0.85 to 0.87 that few ever actually operated it that fast - it just wasn't worth it.
As MarkerInbound notes, part of it may be the statistic affect of the proliferation of smaller aircraft such as the 737 and regional jets (although the NG/MAX is faster than the classic 737, it's still basically sub 0.80 cruise).
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Old 22nd Nov 2021, 22:57
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It's worth looking out for the periodic analyses done by OAG, looking at how block times have varied over the years on specific routes (though of course there are other considerations as well as cruise speed that come into play when accounting for variations).
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Old 22nd Nov 2021, 23:47
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wiggy

We’re pretty chilled rattling between .81 and .86… Makes s0d all difference to the overall block time when your arrival gate is occupied!
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Old 23rd Nov 2021, 08:44
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The carbon footprint of regular business jets is increasingly criticized, so flying around in something that’s bound to emit even more for a speed advantage is not going to endear you to the public. While that certainly won’t deter all possible buyers it is bound to deter an increasing percentage.

The increased market presence of GTF and the possible re-emergence of open rotor fans (or maybe even a new turboprop) might lead to an overall slowdown for environment’s sake. For many applications it doesn’t really matter whether you cruise at M0.6 like a Dash 8-400 or at M0.75-.80 because the difference in overall travel time is minuscule but the fuel savings are huge.
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Old 23rd Nov 2021, 16:18
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MarkerInbound

Having flown the CRJ and the A320 and neo... We operated the CRJ at higher speeds in almost all phases of flight than we did with the A320's... standard cruise speed for our CRJ was .78-.80 - in the A320/1 its been .76-78 and in the neo depending on weights .74-.76 unless we were heavy...
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