LmRaptorLmRaptor“It’s funny how you permanently use 36kft as a tropopause altitude, which is actually a tropopause at standard atmosphere.”
Yes there is a reason I said that – because anything above 36kft and 20km+- has the same standard atmosphere temperature around -56 deg C… so we know that the Mach relation will be identical to the GS in that entire range. All we need to know is above 36kft and it comes down to the same thing. All A/C that we compare will fall in this bracket…
LmRaptorBut that’s the point.
Each word must have single meaning. Once one starts to imply, then we have situation like we have today on forum.
So, we know(?) mr.Metz implies 36+ kft for his 1600mph, but we also know(?) one implies std.atm. when claims M2.42.
If you’re seeking to establish a basis in principle, you need to eliminate loose variables and put them under control, generally presenting them as constants.
We know he implies it because he is indicating the F-22s top speed – which will be around 36kft because its approximately the optimum speed altitude for military turbofans.
LmRaptorMy mistake. It was GS I meant, instead of TAS, so just insert GS instead of TAS in my last post.
So, GS doesn’t solve the problem, due undefined altitude (difference between IAS and GS) and so again, you have variable as you have in Mach number.
No – but when someone says an aircraft will break 1600mph – ie implying its around the top speed or at least the top speed he is willing to admit to. It means you have the basic altitude range by logic – ie around 36kft.
LmRaptorThe point is speed – both TAS/GS are better reference points for comparison than Mach. You also know if the F-22 in w/e wind conditions is capable of doing 1600mph GS as Metz indicated – it is capable of doing Mach 2.42 in std.atm. Anyone with basic logic would understand that the possible altitude range of Metz’s speed is around +-36kft. Those are the points.
LmRaptorIF it’s TAS and not IAS. In this case it’s pretty clear for ppl who know the order of magnitude, but saw on EF’s thread a guy that mixed lbs and kg for an empty EF!
Well, if that’s possible then IAS/TAS is certainly possible as well, especially in slower plane’s case.
So, either use 1600mph TAS, or Mach 2.42 (std.atm.) and both will work, but NEITHER 1600mph or M2.42 will work without clarification, so it’s perfectly equal which is more inaccurate.
No because GS relates to Mach – While TAS and Mach don’t relate.
Thats because if you fly at 36kft over two different flights in the same standard atmosphere temperature conditions while doing a TAS of 1600mph in both flights – you can have totally different Mach values – depending on wind direction.
Thus using GS or Distance/Time – is a better reference – as it gives the same Mach value for a given GS in std.atm.
LmRaptorBut of course we won’t be given the altitude and even less been told what the Designed Maximum Mach is, in particular the inlet recovery factor which would resolve the issue once and for all.
Lol what are you on about – if you can’t understand what altitude he is refering to you don’t understand the basics – IT IS OBVIOUS he is talking about in top speed altitudes – ie around 36kft… unless you think the F-22 can do 1600mph at 100ft…
lol
LmRaptorSens – what are you talking about?!?! When someone talks about a speed value – you need to take it down to first principles lol… as in distance over time. Or the value used in mach calculations – something known as ground speed. He isn’t going to be refering to IAS/TAS or Mach as they are dependent on variables… He is simply talking about its Ground Speed lol…. something a casual observer can actually understand – so for all you skeptics who think this is just some PR statement – logical reasoning would suggest he was refering to Ground Speed. Not something the causal observer would struggle to understand, ie IAS/TAS.
LmRaptor>> M2.4 – WTF?!, 1390kts – nice but still low and finally 1600mph – nice large (touristic/LOL) number. << This is a reasoning pattern of an average observer and nobody cares if it says kts or mph behind.
This is an old marketing trick and I believe this is the point the guys were trying to make.
Which is why actual speed is more relevant… ie a GS of 1600mph so F-22 skeptics can’t claim a marketing trick. If you are given a Mach there is room for error – as its could be calculated on standard atmosphere and not actual atmosphere. If one has a GS however – you know exactly what the machine is capable of.
LmRaptorWhich is Mach 2,1 – when it is a ground-speed value. 😉
Close to the mark of Mach 2 class claim about the F-22A.
Ground speed or actual distance/time is TAS + wind speed… the value that goes into the Mach equation….
If the ground speed is 1600mph and the atmosphere is behaving to standard contions thats a speed of Mach 2.42 at 36kft.
LmRaptorHere you do show behind doubt, you have no real idea about that issue.
Either Metz or the journalist did use a thrilling number for the public from a special demonstration flight. “How far can a prototype be pushed to get all available red warning lights”
See the lack of the related details about that claim attributed to Metz, when he have claimed that the speed of the F-22 is classified at the same time. 😮
1600 mph does look impressive, but is off the mark. The most Paul Metz could have give away had been Mach 2+. Even the higher supercruise values are demonstrated ones and related to special conditions. The best someone can read about that is Mach 1,5+ high-up.In the HUD Symbology the speed is shown in IAS or in the Mach-number.
Some modes do show two numbers (navigation or limitations in mind), the selected speed number for the mission plus the real number, when differing from that or get the related warnings. Like high AoA and speed too low or too fast for some stores f.e..
The instrument inside does show kt IAS on the left side, the digital value in Mach and the Mach scale to the right. Just in case of a HUD failure.
Only during taxi and close to sea-level the shown values of IAS are close to TAS in still air.
Not my explanation, but it does show, that it is not enough to convert some data by a calculator or by brainpower as some will make us believe in their much more “innocent” view.“By definition, “calibrated airspeed” is indicated airspeed, corrected for position and installation errors (i.e., errors that result from the position of the pitot and static system in the changing flow field as a result of varying angle of attack & configuration; as well as error that result from the physical installation of the lines, etc.).
Once you have determined the calibrated airspeed, you may use that to calculate true airspeed…in faster aircraft, the calibrated airspeed is first used to calculate equivalent airspeed, then true airspeed. There is a mnemonic, “ICE-T” which stands for “indicated – calibrated – equivalent – true,” which gives the order in which you proceed. Below about 180 knots, equivalent airspeed may be omitted, as the effect of ram temperature rise is negligible…so for the typical trainer or light twin, the order becomes “indicated – calibrated – true.”Aircraft do fly seldom through still air only. For the ease of understanding I do use an extreme example not unknown to fast jet pilots.
http://en.wikipedia.org/wiki/Jet_stream
High up you will find jetstreams of several hundred kt and that will alter your real speed over ground too. See some record flights from West to East about that, when some airliners where “supersonic” over ground and the Machmeter did show Mach 0.82 only.So much about propaganda, when it does come to the related speed, when some values are watched in the cockpit. .
Lol Sens, I’d have to understand basic concepts like that or I would have failed my units 3 years ago where I had to write software for aircraft speed adjustments…
What you say is irrelevant as I have stated – due to the fact that Metz was a test pilot privy to the aerodynamic performance data of the F-22. He could have taken the data directly from Ground Speed measurements from GPS…
Again it is irrelevant if wind speed is added or subtracted – the point is according to Metz – the F-22 can do 1600mph…
LmRaptor@LmRaptor, chill. You’re gonna get yourself a heart attack. 😀
“Lol – if he states it can do the non variable 1600MPH it can do it lol – Mach is irrelevant.” – Your words…
Ok. It’s pretty clear he’s talking about 1600mph TAS, but he never states that so it isn’t really 1600mph – non variable as you said, as it could be 1600mph IAS, so you have a variable situation as well.
If you want to set things on the principal basis fine, but make sure you got all (or at least main) aspects covered.
This is why Mach, at standard atmosphere, is commonly used.
It is clear he refers to a ground speed value….
LmRaptorDare2, as has been established prior to this, you are a troll! You elicit characteristics of people who have been banned here before.
LmRaptorWRONG: And please do not insist further into trying to imply it isn’t, some more advanced people than you are saying otherwise.
Stop Being fool – learn to quote and spell properly please. I wasn’t aware that someone could be more innately advanced than someone else either… In addition, no one other than a fool says otherwise – this is established practice.
Mach IS a 1976 ICAO reference value and used for everything related to design points as sub, trans and supersonic flight regimes are calling for different solution and imposes different limits/solutions, it is also a value in itself within this International Atmospheric standard with a fixed speed of 1116.89 ft/s or 331.45 m/s.
STOP TALKING MUMBO BLOODY JUMBO lol…. I understand the history and convention in the use of Mach – I have been lectured on it by industry professionals – professionals that have helped design aircraft you have probably flown on.
According to your own rigid theories it does, according to its international standard as i quoted and given the apropriate reference of, it doesn’t.
These aren’t my theories – this is fact – fact you clearly fail to understand. This international standard you talk of is the practice of calculating Mach against standard international atmospheric conditions – namely the standard local speed of sound at a particular altitude using the standard temperature. But the fact is in real life atmospheric conditions VARY – so when SOMEONE quotes a Mach value from a particular flight – it is likely to be slightly inaccurate if calibrated against standard and not real atmosphere – since the real temperature WONT be the same as the standard temperature.
If a test pilot however says that an aircraft can do 1600mph – it means the aircraft can travel at 711m/s! He doesn’t need to convert back from Mach to velocity… he could just be reading the velocity in kts from the dynamic pressure measurements off the pitot tube … or flight data or predicted data from the engineers.
Thus SPEED is a much better reference than Mach – SINCE speed in the MACH equation is simply a DISTANCE/TIME relation and not dependent on atmospheric conditions. While Mach also DEPENDS on the local speed of sound which isn’t accurate if one uses standard atmosphere… in actual flight that varies from the standard convention..
Happy or not Mr Raptor One, not only does this standard exist but is used by people like Paul metz and his collegues at Edward AFB and tother AF Base in the western world.
Lol – if he states it can do the non variable 1600MPH it can do it lol – Mach is irrelevant.
And WHICH speed are you refering to exactly Mr Raptor One?
Are you blind?
He uses a PR quotation which he wouldn’t if he was speaking to someone his size.
Stop sucking stuff out of your thumb.
NO they are not.
It is also non-standard and certainly does not allow you to make assumption the amplitude you allow yourself to, had he called a Vc, Ve or Vt then you would have been able to call it a”SPEED” and would have had to call it in kt as well.
WRONG, it is Designed Maximum Mach which will “give you” the speed you do, not theories based on non-standard measurements unsuable for proper calculation.
And this NOT at ANY altitude but within the dynamic flight envelop of engine and inlets, but of course you prefer to ignore this reality as it allows yourself and buddies to try to pass this value for a F-35 KPP.
As you do, so please keep the M 2.42 at 11 km for those who doesn’t understand what they imply.
Are you sure you understand what you are saying?
Funny i was under the impression that there is a firm distinction between COULD and CAN and that Max Mach can be reached at 15.000 ft and still satisfy your trucker’s standard for 1.600 mp/h.
What are you even trying to say?
Which would be 50.000 ft.
No its 36000 ft….
lol
LmRaptorDare2
Sferrins picture of Picard sums up your level of understanding in this particular case. You continually talk mumbo-jumbo about the relation of Mach to Speed – This is Aeronautics 101 and you are getting it wrong…
Speed or velocity is the reference value – not Mach – speed doesn’t vary – Mach does – its dependent on temperature and thus altitude as there is a standard temperature lapse rate as you increase your altitude. But speed is constant whether you are at 0 ft or 36000 ft….
So when people use the F-22s speed – stated to be 1600mph – they are using the correct reference for comparison – as it is constant. If you know a machine is capable of X speed – you can work out its Mach at any altitude against standard atmospheric conditions. However when you are given a quoted Mach Y from a particular flight – you cant as accurately compare them. This is because one doesn’t know the particular ambient conditions of that particular flight.
What this comes down to is -according to Metz – the F-22 can do 1600mph – at altitude obviously. Therefore in standard conditions the F-22 is capable of doing Mach 2.42 at altitude.
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