billeinstein
最新回复 发布由 billeinstein
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I have never seen any aircrafts pilots notes, flight manuals or anything else that has listed critical speeds in TAS, its always IAS/CAS & Mach.
VNE limits are usually IAS/CAS and Mach whichever is reached first. Block 50 F-16 VNE is listed as 800KIAS/2.05M for instance.
Same for stall, manoeuvring, flap and gear limit speeds.
TAS has its place for flight planning and other things but it's not that relevant to a discussion about what a pilot actually uses while flying imho. I'd rather know how much G potential and energy the aircraft has then how quickly I'm actually traveling through the air tbh.
For energy and G calculation , it must use TAS. Mach number is from TAS, not IAS.
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How convenient isn't it? Care to share something from the P-51's Pilots Flight Operating Instructions? Because it is full of IAS tables, just like NATOPS, Airbus FCOMs and most of the other manuals.
Anyway, I see this has turned into a 'look I'm right' discussion. I provided my arguments of why IAS is more interesting for performance charts than TAS. You can keep throwing archaic diagramms all you want, that doesn't change physics and how things are calculated. If you want to insist, so be it. I only hope that your translation work is more accurate than your research on aeronautical literature.
You know there is no TAS indicator on most early wwii fighters. But in every performance test charts from the test flight it was converted to TAS. Do you know why?
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Good that you mention these parameters, because TAS is either irrelevant for them or they are much more conveniently conveyed with IAS.
I have seen a lot of aircraft manuals, both russian and western, military and civilian, including (admittedly small) AC I flew myself. And in almost every performance chart for TO/climb, descend, loiter/cruise and landing, IAS (or CAS) is used. And this is only logical because A: IAS is a major factor in calculating aerodynamical forces and B: it is known by the pilot at any time.
If you don't believe me, get yourself any aircraft performance manual and have a look.
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Sorry but that's plain and simple wrong. Have you even looked at turn performance tables?
Do you know the Mach number is TAS/speed of the sound at that condition?
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These two are closely linked. How will you know your TAS or any speed if don't know thrust and drag? How will you know g-load if you don't know lift?
Your initial claim was:
That is simply not true. Basic geometry like turn radius equals g load and TAS is not aircraft performance, it's much more complicated as I already outlined.
I can assure you that most of the aircraft performance charts (which literally have the word 'performance' in their title) are not what you are describing.
Welcome to DCS forums, where arguments and opinions are sometimes the same...
The performance of an aircraft mainly are how fast and how high it can fly, how tight and how fast it can turn, and climb, etc. you will unlikely to see IAS in it.
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Well, in this case any further discussion is definitely useless. I'm starting to believe that you and The Falcon are actually twins. Over and out.
Can you understand the steady turn is a constant radius turn? Wind just make the turn center move, not changing the radius. Just like a wheel rolling on the ground. Every point on it have a constant turn radius, but the center is moving forward.
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You honestly believe that the turn radii are identical when turning into a 100kts tailwind and into a 100kts headwind?
Yes. It's a steady turn.
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And how is it possible that the performance section of the manuals can do that with IAS?
If you can do it with IAS, but more date must be needed such as tempreture and pressure. First convert the IAS to TAS with them, then calculate the rest.
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NO! How on earth do you calculate the turn radius without knowing the wind direction?!?
Turn on the smoke during the turn and it will tell you why not count the wind.
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Turn performance depends on a lot more then just TAS. Weight, drag, pressure and a lot of other factors play into the equation to account for all the forces in play. For the aerodynamical forces (i.e. lift and drag), IAS and Mach number are the important values and they are also the values presented to the pilot in the cockpit. They are therefore the ones provided (among other things) in aircraft performance charts. Of course there are exceptions, like cruise performance data where TAS is important for navigational purposes. But mostly, IAS and Mach are used.
That's dynamics. The mesuring the perfomance of an aircraft mostly means kinematics.
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For another example, your aircraft is in steady level turn in steady wind.
Your IAS is 300 kts, you are pulling 3 G in the turn. Wind speed is 50 kts.
You can't calculate your turn rate or turn radius with these information.
But if you know your TAS, for example is 350 kts, you can calculate them with it and get your turn rate is 8.82 deg/s, turn radius is 1170 m.
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Exactly, but then we are talking about IAS again and not TAS.
Since the wind is usually blowing in only one direction and you and your opponent are hopefully not flying in formation, you turn radius and lead angle calculation will be incorrect without GS and wind direction.
Since this is way off topic and it's unfortunately very similar to the discussion with The Falcon, I'll let you guys continue this never ending thread on your own.
The calculation can be done perfectly without GS and wind, but only TAS. The air of steady wind is an inertial reference system.
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Again, once an opponent is added to the equation we are talking about position/navigation, you would 'theoretically' need to know GS and wind direction. Otherwise your whole 'calculation' will be wrong.
No, there is no need for GS and wind caculation in ACM. Only A2G aimming need those correction.
There is no different for whether the air is moving (wind) or the ground is moving reversely.
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In ACM You don’t actually care exactly how tight your turn is, you care that you’re max performing the aircraft, and when it comes to that TAS is pretty meaningless, IAS and AoA are much more useful measurements. Corner speed and best sustained turn airspeed are both usually quantified in IAS not TAS.
But your energy management must use TAS. Max rate turn is only one case in ACM. IAS tell you how to get max turn rate, TAS tells you how Max the turn rate can be. The radius doed affect the head to head dogfight for example, to chose one cirlcle fight or two circle, or how to keep your seperation and to pull how many leading turn.
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If you insist on calculating your turn radius precisely during a dogfight, for whatever reason, knowing the ground speed and the wind direction would be essential as well.
No. For a steady turn in constant wind condition, the turn radius is always changing looking from the ground (navigation flight path). But for the aircrafte perfomance caculation, you ARE flying in a circle with constant turn radius.
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Maybe times have changed over the years. When we did 1 vs 1 and 2 vs 2 dogfights IRL we certainly didn't use the above formulae.
Without any AoA gauge the only important things were our eyes and IAS.
This additional TAS/performance thing doesn't do anything to help clarify things in this thread and for The Falcon in particular.
For example, for turn radius, TAS and G, you can get one of them with two others are known. IAS can't. If you don't care how tight your turn is, you don't need TAS.
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This doesn't make much sense IMO in your mentioned combat scenario. Furthermore if both aircraft are at roughly the same altitude, TAS will be the same for both at the same IAS. So what would be the point to know TAS?
Especially when maneuvering close to, or at the edge of the envelope, I'm much more interested in IAS than in TAS.
TAS * flight time = the length of flight path.
TAS^2/radius = |vector {G + gravity}|
That's the performance.
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Corner speed is in TAS?
Corner speed is for pilot to maneuver. To evaluate how good the aircraft turn, you must use TAS.
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Please don't cut the rest of the part. Sure it can but if we are talking about an f-16 with 200kts headwind he can easily push and go beyond the 0 groundspeed.
Which pilot in reality would be carried backwards by the wind?
Try the AV-8.
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So all flight manual performance tables like climb & turn performance & stall speed etc. are useless?
IAS is very useful for pilot to handle the aircraft. But it's useless for performance ralated like energy analysis, BFM tactics etc. You'll never care about your enmey's IAS in combat, but only his TAS.
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No. Climb rate, turn rate, stall speed etc. is usually measured in CAS/IAS/EAS not TAS.
CAS/IAS/EAS is mostly for dynamic/structural strength/load caculation, not performance.
If you use IAS for turn performance, you will get a circumference of 360 degrees turn less than 2pi*radius.
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