Search found 35 matches

by PerVG
Wed Aug 07, 2019 5:21 pm
Forum: Civil Aviation
Topic: First full electric airline service
Replies: 24
Views: 3434

Re: First full electric airline service

Well, not the biggest challenge ever, is it? :mrgreen:

Image

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by PerVG
Fri Aug 02, 2019 6:43 pm
Forum: Technical/Operations
Topic: Max Engines
Replies: 26
Views: 7699

Re: Max Engines

While C version (Comac) is a bit different animal, A version is pretty similar. Boeing (with its lower gear) required different fan, but otherwise, they're very similar (if not identical). Actually, it's the A and C that are similar. They have approximately the same size, thrust ratings and core st...

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by PerVG
Sat Jun 29, 2019 8:05 pm
Forum: Technical/Operations
Topic: Falcon business jet horizontal designs - what are the advantages?
Replies: 10
Views: 2254

Re: Falcon business jet horizontal designs - what are the advantages?

The midway arrangement might be less susceptible to deep stall conditions. That's a possible advantage.

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by PerVG
Tue Jun 25, 2019 6:38 pm
Forum: Technical/Operations
Topic: GE9X Record Breaker
Replies: 60
Views: 10113

Re: GE9X Record Breaker

Overengineering is not the same as good engineering, although it might seem like it. ;)

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by PerVG
Tue Jun 25, 2019 5:06 pm
Forum: Technical/Operations
Topic: GE9X Record Breaker
Replies: 60
Views: 10113

Re: GE9X Record Breaker

Being an engineer myself I can say that, in general, overengineering is indeed a wast of money and resources/weight, maybe. Now, I'm not presuming to know more than GE about their own engine, and I'm sure that there are good reasons for it being as it is. It's just that 20%+ seems like a rather high...

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by PerVG
Tue Jun 25, 2019 12:09 pm
Forum: Technical/Operations
Topic: GE9X Record Breaker
Replies: 60
Views: 10113

Re: GE9X Record Breaker

Its very likely. Ted Ingling (GE Aviation’s GE9X program manager ) said the GE9x has unofficially beaten the GE-115B record thrust in cold weather triple red line conditions and stated a new record for the books will be forthcoming. That means at least 121% of rated thrust.. very impressive. But al...

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by PerVG
Sat May 18, 2019 12:01 pm
Forum: Civil Aviation
Topic: JetBlue switches from Coke to Pepsi
Replies: 193
Views: 19763

Re: JetBlue switches from Coke to Pepsi

HOW DARE THEY? :D
Pepsi is crappy, but who really cares, anyway?

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by PerVG
Sat Apr 13, 2019 2:18 pm
Forum: Technical/Operations
Topic: Are these contrails alarming?
Replies: 40
Views: 5323

Re: Are these contrails alarming?

Did you really use the word "alarming" in respect to contrails? :lol:

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by PerVG
Tue Apr 09, 2019 12:27 pm
Forum: Civil Aviation
Topic: Airbus And Boeing 2019 Deliveries
Replies: 61
Views: 9869

Re: Airbus And Boeing 2019 Deliveries

Once the grounding is lifted, Boeing might even deliver 200, 300, heck, maybe 500 aircraft in one month. But can we really call it a win, then? In the end, it shouldn't be much different than the last years, approximate total numbers for the two, with Airbus edging out the NBs (this year maybe more ...

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by PerVG
Wed Apr 03, 2019 7:31 pm
Forum: Civil Aviation
Topic: Welcome to 'Cattle Class'
Replies: 114
Views: 20132

Re: Welcome to 'Cattle Class'

The briefest "hop across europe" I have ever done was LIS-MAD, it's barely a 1 hour flight and there's just no way in hell I would do it in on of those contraptions. Let alone anything longer than that. This is one of those things that needs to be killed by the regulators before it gains a...

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by PerVG
Tue Apr 02, 2019 5:04 pm
Forum: Technical/Operations
Topic: Optimum materials
Replies: 17
Views: 1794

Re: Optimum materials

Thanks for that. What about a Titanium alloy? What are the pros and cons of that? Wasnt it used on the SR71 for structure and skin? Have the potential titanium alloys advanced since then? Is it suitable? Titanium has the strength of steel with half the weight. It can also tolerate very high tempera...

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by PerVG
Tue Apr 02, 2019 1:09 pm
Forum: Technical/Operations
Topic: Optimum materials
Replies: 17
Views: 1794

Re: Optimum materials

Not sure there is one "very best". As mentioned, it's all a compromise. Even excluding cost, you have to consider weight, strength, repairability, safety, workability, etc... Among metals, you have magnesium alloys that are lighter than aluminum ones, but are also weaker and difficult to w...

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by PerVG
Tue Apr 02, 2019 12:33 pm
Forum: Technical/Operations
Topic: Could a quad use different combinations of engines?
Replies: 35
Views: 2192

Re: Could a quad use different combinations of engines?

I am thinking, in this thought exercise, about a clean sheet design concept, where optimal cruise engines are supplemented by retractable thrust to be deployed when needed i.e at takeoff. That concept already exists as a possibility for future hybrid aircraft, were electric fans augment a cruise ga...

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by PerVG
Thu Mar 28, 2019 2:21 am
Forum: Travel, Polls & Preferences
Topic: Could the US eventualy end up with just 3 major flag carriers
Replies: 29
Views: 3967

Re: Could the US eventualy end up with just 3 major flag carriers

drdisque wrote:
Spirit didn't exist in 1982. It was founded in 1984 and didn't begin scheduled operations until 1990.


Nor did JetBlue, who operated less than a year in the 20th century...

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by PerVG
Wed Mar 27, 2019 12:54 am
Forum: Civil Aviation
Topic: Harbour Air poised to start worlds first all electric fleet
Replies: 32
Views: 3568

Re: Harbour Air poised to start worlds first all electric fleet

Well sure, when your longest route is 140km (75nmi) and you can land anywhere between and just sail the rest of the away, you can toy around with electric planes..

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by PerVG
Thu Mar 21, 2019 7:28 pm
Forum: Civil Aviation
Topic: B737MAX Grounded Worldwide Q1 2019
Replies: 6476
Views: 720100

Re: B737MAX Grounded Worldwide

Mr Sully only achieved his remarkable feat because he had an excellent copilot. It'd be polite to recognise that. Can you even name him without searching? First and foremost, he achieved that because he was in an Airbus A320 which comes with the flight envelope protection system. As per the NTSB re...

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by PerVG
Wed Mar 13, 2019 7:10 pm
Forum: Civil Aviation
Topic: B737MAX Grounded Worldwide Q1 2019
Replies: 6476
Views: 720100

Re: Should airline regulators consider grounding B737 MAX series

It’s going to be embarrassing for the whole world when the accident cause is unrelated. It will not be embarrassing for anyone. There is circumstantial evidence that both crashes may have something in common and it may have something to do with the aircraft type.Even if the chance is only 1/1000 th...

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by PerVG
Mon Mar 11, 2019 11:34 pm
Forum: Civil Aviation
Topic: B737MAX Grounded Worldwide Q1 2019
Replies: 6476
Views: 720100

Re: Should airline regulators consider grounding B737 MAX series

Given the two eerly similar accidents with massive loss of life of brand new aircrafts, particularly when the shady implementation of a new control system *might* be linked to them, I have little doubt that they are indeed considering a grounding. It's their job. Which isn't to say that they should ...

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by PerVG
Thu Feb 28, 2019 2:35 pm
Forum: Technical/Operations
Topic: GE9X Record Breaker
Replies: 60
Views: 10113

Re: GE9X Record Breaker

The GE90's 127k lb figure was obtained during mandatory triple red line (maximum N1, N2 and EGT values) testing for certification. Source: https://www.geaviation.com/press-release/ge90-engine-family/ge90-sets-new-world-record-thrust-engine-completes-far-33 As for what the GE9X might do under the sam...

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by PerVG
Wed Feb 27, 2019 9:05 pm
Forum: Technical/Operations
Topic: GE9X Record Breaker
Replies: 60
Views: 10113

Re: GE9X Record Breaker

Not very likely, IMHO. What would be the point of it, anyway? They already have the record, with the "bragging rights" that come with it. And that record came from normal testing, not from any intentional "record run". As for the GE9X, it targets a lower thrust point than the GE9...

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by PerVG
Sat Dec 15, 2018 2:29 pm
Forum: Non-Aviation
Topic: Climate Change And Airlines
Replies: 133
Views: 8639

Re: Climate Change And Airlines

Aviation might be a "small" contributor to the problem (transportation represent about 15% of global greenhouse gases emissions, and aviation is just a part of that), but we are at a point where every single gram of CO2 counts. That fact that are bigger contributors is not an excuse to not...

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by PerVG
Fri Dec 07, 2018 12:37 pm
Forum: Technical/Operations
Topic: GTF vs. triple spool engines
Replies: 33
Views: 2979

Re: GTF vs. triple spool engines

I would think that a power transferring gear set (one which, I assume, must have at least a thrust bearing component itself) would lose more energy than a couple of extra bearings. Am I wrong?

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by PerVG
Sun Aug 05, 2018 10:57 am
Forum: Technical/Operations
Topic: Supersonic Business Jet Engines
Replies: 24
Views: 2411

Re: Supersonic Business Jet Engines

lightsaber wrote:
What wasn't mentioned is multi-stage fans.


I did mention them. :D ;)

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by PerVG
Wed Aug 01, 2018 11:20 pm
Forum: Technical/Operations
Topic: Supersonic Business Jet Engines
Replies: 24
Views: 2411

Re: Supersonic Business Jet Engines

I always thought of the EJ200, Snecma M88 and F119/YF120 as good basis for engines to power hypothetical new supersonic transport aircraft. The first two for business jets and the latter for airliners.
All of them are relatively modern designs and conceived with supercruise in mind from the get go.

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by PerVG
Wed Aug 01, 2018 5:50 pm
Forum: Technical/Operations
Topic: Supersonic Business Jet Engines
Replies: 24
Views: 2411

Re: Supersonic Business Jet Engines

In a perfect system, you could accelerate a bit above the exhaust speed of an air breathing jet engine, do to the added mass of fuel to the total flow. ;) In practice, yeah, you need to accelerate the exhaust above the speed you want for the plane. And that's not going to happen with high bypass tur...

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by PerVG
Thu Feb 15, 2018 11:24 pm
Forum: Technical/Operations
Topic: Feasibility of high altitude commercial aircraft
Replies: 6
Views: 1541

Re: Feasibility of high altitude commercial aircraft

and we were discussing why you couldn't hear the sonic boom for the launch (but you could hear it on reentry) and he said something to effect of the fact that after a certain altitude, you can't effectively hear a sonic boom. I'm no expert or anything, but might be that a big factor in not hearing ...

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by PerVG
Tue Feb 13, 2018 11:52 pm
Forum: Civil Aviation
Topic: Ryanair has best passenger load factor of 96%
Replies: 31
Views: 4708

Re: Ryanair has best passenger load factor of 96%

I don't think a 96% load factor is something worth striving for. Calculations I've seen elsewhere suggests the sweet spot is around 85%. If your load factors are near 100%, you should increase the prices of tickets until it drops to around 85%. That's where you make the most money. Not sure that wo...

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by PerVG
Tue Feb 13, 2018 8:01 pm
Forum: Civil Aviation
Topic: A321 NEO LR LBG - JFK Flight Tracker
Replies: 59
Views: 11979

Re: A321 NEO LR CDG - JFK Flight Tracker

Just got back to live tracking and doing about the same speed as all other aircraft on a similar fly path.. ;)

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by PerVG
Tue Feb 13, 2018 12:24 am
Forum: Technical/Operations
Topic: Bypass Flow and Core Flow velocities
Replies: 5
Views: 686

Re: Bypass Flow and Core Flow velocities

Can't be absolute. In order to produce thrust, bypass flow must be accelerated above the vehicle speed. I would guess the delta starts big at take off and then gradually shrinks as the plane picks up speed. But never reaches zero. Core flow could produce thrust at absolute speeds equal or even a bit...

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by PerVG
Sat Feb 10, 2018 4:36 pm
Forum: Technical/Operations
Topic: PW1100G aft hub modification failure
Replies: 53
Views: 5670

Re: PW1100G aft hub modification failure, deliveries halted

GalaxyFlyer wrote:
The only other geared fan engine, the TFE 731


There's also the ALF 502, at least.

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by PerVG
Wed Feb 07, 2018 12:24 pm
Forum: Military Aviation & Space Flight
Topic: SpaceX - Tests, Launches, Developments
Replies: 2061
Views: 244460

Re: SpaceX - Tests, Launches, Developments

Add a Vulcan second stage one day and there is nowhere in our Solar system it can't go. Vulcan is the Ariane engine, did you mean Raptor engine instead? He might be referring to the future Vulcan rocket, by ULA. I highly doubt that ULA would be willing to supply ACES upper stages to SpaceX, though....

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by PerVG
Wed Feb 07, 2018 9:10 am
Forum: Military Aviation & Space Flight
Topic: SpaceX - Tests, Launches, Developments
Replies: 2061
Views: 244460

Re: SpaceX - Tests, Launches, Developments

Watching the live stream of the post-launch news conference, Musk has confirmed that the core did indeed not land safely. As far as I could hear (the audio quality was a bit meh to start out with), it ran out of propellant and hit the water at 300 MPH I understood it run out not of propellant but o...

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by PerVG
Tue Feb 06, 2018 6:44 pm
Forum: Technical/Operations
Topic: What makes the B737 an "old, outdated" design?
Replies: 143
Views: 13541

Re: What makes the B737 an "old, outdated" design?

I would add that a bit of an hard impact upon "landing" was far better than a possible much harder impact upon falling down after stalling, had not the flight envelope protection been in full effect. :)

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by PerVG
Sun Feb 04, 2018 1:06 pm
Forum: Travel, Polls & Preferences
Topic: Use of Electronic Device/Headphones Policy Question
Replies: 7
Views: 660

Re: Use of Electronic Device/Headphones Policy Question

Perhaps it's a safety thing? So that passengers will be readily aware of any crew indications in an emergency situation?
Some airlines might think it makes a difference, and others not so much.
Just guessing, here... ;)

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by PerVG
Tue Jan 23, 2018 11:06 pm
Forum: Civil Aviation
Topic: Norway is to make all short-haul planes electric by 2040
Replies: 252
Views: 16655

Re: Norway is to make all short-haul planes electric by 2040

*Or did I calculate something wrong? Entirely possible. I know engine efficiency is not in the calculations but it should be good enough to not cause problems. You did. Hint: 18650 cell can provide 80W of power for how many miliseconds? Many. I would appreciate if you could spend at least few secon...

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