ground speed

[Big Pistons Forever]

Every pilot should be able to do a circuit with the ASI covered. It is no big deal and I often use this technique with more advanced training for pilots who have gotten into the bad habit of chasing the airspeed

There really should be no reason to look at the GPS if you know the basic power settings and pitch attitudes for the normal phases of flight.

[rapidshot]

Big Pistons, i very well agree with you but within years as hours built up that training occupies a small fraction of hours flown, everyone gets used to scan those instruments,
i bet everyone will remember the most famous sentence , "watch your speed first", so i dont think some basic skills will develop under these circumstances or there was something wrong with the way i was trained,

Also there is a concept i first met almost a year ago, i really wish to learn what you all think about attitude flying using "bar width",

[abgd]

As for landing if there is tower, attitude plus GS both may be used, Without tower i agree with attitude flying only,shortly this is the summary i extracted for myself,

I don't really understand what you have in mind there - perhaps that the tower will give you the airspeed at ground level, so you can compensate?

I'm still don't think I'd go with that - winds can change quite quickly, or even blow in opposite directions at each end of the runway.

[rapidshot]

I don't really understand what you have in mind there - perhaps that the tower will give you the airspeed at ground level, so you can compensate?

that is exactly what i think, my opinion is if the wind changes quickly any method should take you in trouble without ASI,

[Pilot DAR]

the most famous sentence , "watch your speed first", so i dont think some basic skills will develop under these circumstances

It is true that too much concentration on instruments will distract a pilot away from "feeling" the plane during maneuvering. Any single engine certified GA type will give the pilot ample feel, as to how it is flying, and what it's speed is relative to the stall. The idea that a slow to refresh, uncorrected GPS groundspeed has any use to replace an ASI for maneuvering type flying is silly.

This, to me, speaks of the trend away from learning to "fly" a plane, toward learning to read what its indicators are telling you - because the computer flight simulators are demonstrating that. It's easy for the computer to provide lots of data, and decent visuals. Its difficult for appropriate force feedback to be provided by the computer, and impossible to simulate G forces.

The interpretation of all of these cues in combination is what it takes to fly well. Yes, you can still fly with a cue or two missing, but it will be less well.

It's nice to have all of this extra information when flying, and sure, I use it too, but it is a vital basic flying skill to be able to feel what the plane is telling you, in the absence of indicated numbers. Ths is particularly important when you're flying something different, and you have not memorized all the speeds anyway! (Some planes don't have coloured bands on the ASI to remind you!).

You're paying lots to be off the ground, why would you want to give up the only means to actually hone your skills of being "at one" with the feel of the plane, to allow yourself to concentrate on a bunch of indicators which you can also use on your computer at home? Presuming that you're flying in good visibility, and in airspace which does not demand strict adherence to altitudes, Try flying around with no reference at all to any indicator, other than to monitor engine condition an fuel from time to time. When you're realizing how much the plane is telling you without your reading any numbers, try some slow flight that way. Then, go and land that way.

Your slow flight practice will have reminded you of the feel of just getting on the back side of the power curve, and how to just get there, without going too slowly. As long as you can feel that, without the crutch of an indicator telling you, you can safely land the plane in most day VFR conditions.

You'll surprise yourself. And, you'll be that much better prepared to fly safely when something does fail for real! These skills should be practiced regularly

[rapidshot]

Actually my question was not about improving the basic skills but related to, say as an example, speeds under vfr into imc conditions, my fault if this topic turned into a discussion about developing skills,
Since English is not my native language may be i couldnt express myself but my question in one of my replies on Va and Vfe to me is self explanatory, are they ias or tas, i really want to learn and discuss,

[Pilot DAR]

if this topic turned into a discussion about developing skills,

Don't worry Rapidshot, that's what the forum is for...

"V" speeds will be an indicated airspeed (IAS), and related to calibrated airspeed (CAS), which is a corrected IAS anyway. TAS and groundspeed do not enter into it, as the V speed is the affect of the actual air on the aircraft. The aircraft does not care about it's groundspeed (until it touches the ground, but even then, it's only the tires), and for the purposes of the affect of air on the airframe, it does not care about it's TAS.

Of course speeds which are limiting, and expressed as "V" speeds (Vne, Va, and Vfe, for example) must not be exceeded. The aircraft is designed so it is easy, while being careful, to not accidentally exceed these speeds.

You're not going to accidentally exceed Vne during controlled flight, unless you're oblivious to the howling sound of the air, and the whining of the engine at near red line RPM, and an unwinding altimeter. If you've buggered up aerobatics, you could - so obviously, aerobatics with a U/S ASI is very foolish.

If you think you're near or above Va, avoid really rough air, and abrupt control movements until you've slowed. When the controls begin to feel more mushy, you're below Va, and safe to do what you have to do.

In a GA aircraft, there is no need to be pushing Vfe, so just make sure you're nice and slow, before extending flaps, and you'll be fine. During certification testing, Vfe will have been established with a reasonable margin to allow for pilot technique.

Because all the "V" speeds are IAS, using the GPS to adhere to them is troublesome. If you're maneuvering the aircraft and getting close to one of these limits, you're probably too busy to be working out the factors between IAS and GPS groundspeed,

[rapidshot]

May i ask the reason

unwinding altimeter

And last question, if we enter little gusty air, it is obvious that we are not able to know that what is waiting us next, may be a gust at the limits of the envelope, so do you think that we must reduce the speed near Va if we meet such a humble gust,

Edit: and i wonder why Vfe is given as IAS, as we know the inherent dynamic characteristics of the structure such as natural frequencies are independent of the density of the air, but the excitation forces are probably a function of density, so i dont think there is a simple relation like the relation between Tas and Ias when flutter is considered, i really wonder the reason, and i think there is no time to think all of those and make some calculations when the airplane starts to dive,

[peterh337]

I reckon flutter is related more to TAS (the actual airflow velocity) than IAS, but the ASI has to be marked in IAS.

This is why, AIUI, when some aircraft types are modified with a more powerful engine which enables them to climb higher (where the TAS gain over IAS is greater) the Vne figure is reduced.

[Shaggy Sheep Driver]

Hey guys - the airframe doesn't give a fig for TAS. It only feels IAS (and Mach).

[rapidshot]

Hey guys - the airframe doesn't give a fig for TAS. It only feels IAS (and Mach).

This is true only at the sea level without compresibility effects, i guess, lol , your statement will start a new discussion around Eas,

[Shaggy Sheep Driver]

Nope. Think of 'coffin corner'. Consider that all airframe limits are IAS (or Mach) regardless of height, altitude, or FL.

VFE is the same regardless. If your aeroplane is going to stall at 100 knots indicated, it will stall at 100 knots indicated, at sea level or at 40,000'.

[rapidshot]

Depends i think, the designers limit the speeds with the most conservative case , probably that case occurs at sea level with MTOW and they mark that on the Ais,

As for stall speeds obviously it is same at all altitudes due to the logic behind the design of pitot tube, the density is just cancelled out of the equations

[Shaggy Sheep Driver]

No, it depends on aerodynamics. The ASI WILL read 100 kts at the stall in my example above, regardless of altitude (until mach effects come in at very high altitudes and we get mach stall ahead of AoA stall). Doing aeros at several thousand feet would be wierd if all your entry and limit speeds (on the ASI of course) were different to doing them on the deck at an airshow!

You'll be telling me next you get a higher IAS when you turn upwind to downwind!

[rapidshot]

Stall speed is just a measurement, as i wrote before the density has no effect , but as for the Va and Vfe i dont think this holds, to me most critical cases are put in the Poh and the Asi

[Shaggy Sheep Driver]

I hope you are not a licenced pilot, rapid!

Stall isn't rally a speed, it's an AoA. But for an given configuration and weight etc the stall AoA will be reached at a particular indicated airspeed (the point at which the airflow breaks away from the wing's surface). This IAS is always the same for that config etc, though it will occur at vastly different TASs if the air density varies.

[rapidshot]

You'll be telling me next you get a higher IAS when you turn upwind to downwind!

No Sir, i will never tell that, even think of it

[rapidshot]

I hope you are not a licenced pilot, rapid!

,
I am not a pilot, i just hold a pilot license

Stall isn't rally a speed, it an AoA. But for an given configuration and weight etc the stall AoA will be reached at a particular indicated airspeed (the point at which the airflow breaks away from the wing's surface). This IAS is always the same, though it can occur at vastly different TASs.

lets better stop here, i bet we both do not want to find ourselves discussing the solutions of Navier Stokes equations of the boundary layer under this topic, stall is said to be independent of speed but i have always wondered how Reynolds Number affects the max AoA if this is true

I am sure that i Have never spelled the word stall here in this threat before

[englishal]

Briefly.........Vne (and what the airframe "feels") is indeed determined by TAS and not IAS. Vne actually decreases with altitude and if you hot rodded your engine and took your plane up high, you could actually encounte Vne (and flutter) below the Vne marked on the ASI. I guess it is marked on the ASI for a sealevel IAS, because they know that up high the aeroplane as designed would never (in normal flight) reach a TAS which would exceed Vne (due to power limitations of the engine etc). All bets are off if you decided to tinker with your engine and add a Turbocharger (for example) without any further modifications to the airframe.

It is to do with the speed the molecules of air pass over the control surfaces and not the density of the air which will determine when flutter will occur (the reason for Vne).

Here, this explains it better than I can

http://www.vansaircraft.com/pdf/hp_limts.pdf