field of view + ground detail + altitude Is this what 600 knots really feels like?

[draconus]

10 hours ago, RODEO5150 said:

So by increase my FOV, do you mean move the slider to the left?

Slider is for external view. In the cockpit use Num Pad * and / keys. High fov means wide view, higher angle, zoomed out.

The trees are fine.

Edited February 12, 2023 by draconus

[VR Flight Guy in PJ Pants]

Video idea: compare the "down town Dubai" in DCS World and MSFS, at 600 knots in Hornet/Super Hornet. I just have had a short "trip" in the latter, the graphics is not that good but at 60+fps, MSFS has a better sense of speed, it seems..

[razo+r]

3 minutes ago, VR Flight Guy in PJ Pants said:

Video idea: compare the "down town Dubai" in DCS World and MSFS, at 600 knots in Hornet/Super Hornet. I just have had a short "trip" in the latter, the graphics is not that good but at 60+fps, MSFS has a better sense of speed, it seems..

And both at the exact same FOV?

[VR Flight Guy in PJ Pants]

I am not sure how to get it done in MSFS, I can adjust DCS World in VR to match, I think.

[sthompson]

Sense of speed is largely determined by how fast the visual appearance of objects is changing. Those changes include (a) relative size as you move closer to objects, (b) relative angle of objects off your direction of travel, and (c) changing aspect of objects as your angle relative to them changes. All of this is true regardless of your FOV. Even a realistic FOV is going to give you not much sense of speed if you focus on distant objects, especially if they are in your direction of travel because changes in view along the lines of (a), (b), and (c) occur only slowly for such objects. That's why there is a feeling of not moving when flying at high altitudes. But if you get down low and look at reasonably close objects off your 12-6 line, you should get a realistic sense of speed as you pass them, because (a), (b), and (c) are all changing relatively quickly for such objects.

[HoBGoBLiNzx3]

I think a blend of motion blur in your peripherals would definitely help. Not the entire imagine when you move your head though so that objects that move past you would be blurred but not in your direct vision or when you move your point of focus. Also I think there needs to be a better feeling of wind resistance on the camera shake and blur. ELI 21 did a good job cinematically of this in post production. External views have always killed immersion because the aircraft looks like it's rotating perfectly on an axis. Here is the ELI 21 example. 

 

Edited February 23, 2023 by HoBGoBLiNzx3

[trevoC]

3 hours ago, draconus said:

But we can see the speed right on the HUD.

define speed?

You can see the IAS on the hud which tells us nothing we need to know for this test. 

[draconus]

6 hours ago, trevoC said:

You can see the IAS on the hud which tells us nothing we need to know for this test. 

It tells us roughly the aircraft speed. Yeah, it can differ by ex. temperature, but you said about 100kts difference so I'm curious now.

Edited February 24, 2023 by draconus

[trevoC]

7 hours ago, draconus said:

It tells us roughly the aircraft speed. Yeah, it can differ by ex. temperature, but you said about 100kts difference so I'm curious now.

 

At 30,000 feet for example you may have a 260 knot IAS and a 500 knot Ground speed. Much more than 100 knots. Pretty common.

IAS is always shown to pilot as your stall speed is more important than how fast you are travelling, but for this test ground speed would be the most important factor.

Tons of videos on youtube that can best deep dive this for you but the gist of it is IAS is the speed which the aircraft "feels" in other words the wind is travelling 150 knots over the wing which determins stall speed.

Ground speed on the other hand is the actual speed you are travelling across the ground which would effect the "feel or look"

Tons of things effect this...  headwind, tailwind, air density, temperature, altitude etc....

[trevoC]

There are plenty of times you could be travelling close to or exceeding the sound barrier while your aircraft is on the edge of stall speed at altitude. I've fought this limit at 47,000+ feet in an F-15 many times trying to get an edge on a BVR launch to gain an advantage. Aircraft is barely staying in the air but travelling Mach 1 across the ground (IAS around 150 knotsish)

You also have True Air speed TAS which again is different.

For this example though, Ground Speed is all that matters and IAS is really irrelevant.

hope that helps.

Now granted at lower altitudes air density will have little impact, but what is the weather in this example... is there a headwind etc... There could be a 50 knot headwind in one example and a 30 knot tailwind in the other. This is a 70 knot disparity in wind alone that IAS will not indicate. You start adding up all the potential variables and it could be way out.

All I'm tyring to convey (because the comparison is cool to watch) is that it be setup in a manner that could be more scientific (I wasn't claiming that the OP said that, just trying to help with that)

[draconus]

13 hours ago, trevoC said:

Now granted at lower altitudes air density will have little impact...

Good, you've finally catch that because I didn't see anyone asking for IAS definition and I doubt there was any wind set in either flights.

[sthompson]

15 hours ago, trevoC said:

Tons of videos on youtube that can best deep dive this for you but the gist of it is IAS is the speed which the aircraft "feels" in other words the wind is travelling 150 knots over the wing which determins stall speed.

Not quite true. If you are travelling at a ground speed of 500 knots then (ignoring wind) your wing is moving through the air at 500 knots. However the amount of lift generated depends on air density as well as speed, and the IAS adjusts for that by measuring the pressure differential in a pitot tube compared to static air pressure. A better way of thinking about IAS is that it is about the amount of air passing over your wings, not about how fast you are moving through that air. At altitude the air is thinner and so there is less air flowing for a given amount of speed.

[trevoC]

2 hours ago, sthompson said:

Not quite true. If you are travelling at a ground speed of 500 knots then (ignoring wind) your wing is moving through the air at 500 knots. However the amount of lift generated depends on air density as well as speed, and the IAS adjusts for that by measuring the pressure differential in a pitot tube compared to static air pressure. A better way of thinking about IAS is that it is about the amount of air passing over your wings, not about how fast you are moving through that air. At altitude the air is thinner and so there is less air flowing for a given amount of speed.

 

^ Not true at all.

Again, its why I mentioned go elsewhere. I've been flying for 30 years. If you want an explanation its easy to find. "From the ground up" is where I started or a youtube video which I mentioned. No need to garble anything here to someone who may or may not understand. I attempted to explain this for the layman. If you already know, there is no reason to explain.

But if you are going to explain in depth, better get it right.

"your wing is moving through the air at 500 knots" < never said otherwise. But the air moving over your wing is not moving at 500 knots worth of lift which is why it can be confusing for non pilots.

If we really want to be clear, the IAS doesn't adjust for anything and is a direct measurement of air speed via the pitot tube which measures dynamic pressure period. It doesn't measure pressure differention or anything else.

 

[Willie Nelson]

On 2/24/2023 at 9:50 AM, HoBGoBLiNzx3 said:

I think a blend of motion blur in your peripherals would definitely help. Not the entire imagine when you move your head though so that objects that move past you would be blurred but not in your direct vision or when you move your point of focus. Also I think there needs to be a better feeling of wind resistance on the camera shake and blur. ELI 21 did a good job cinematically of this in post production. External views have always killed immersion because the aircraft looks like it's rotating perfectly on an axis. Here is the ELI 21 example. 

 

 

This is such a cool video! 

[sthompson]

3 hours ago, trevoC said:

"your wing is moving through the air at 500 knots" < never said otherwise. But the air moving over your wing is not moving at 500 knots worth of lift which is why it can be confusing for non pilots.

If we really want to be clear, the IAS doesn't adjust for anything and is a direct measurement of air speed via the pitot tube which measures dynamic pressure period. It doesn't measure pressure differention or anything else.

 

As for the first statement, I'm glad we agree, although I'm not sure I know what you mean by "500 knots worth of lift." On the second point, IAS instruments compare the dynamic pressure from the pitot tube with static air pressure. If these are the same you are not moving forward. If different, you are. Dynamic pressure by itself can't give you air speed since it depends on the ambient air pressure in addition to speed. 

[trevoC]

38 minutes ago, sthompson said:

As for the first statement, I'm glad we agree, although I'm not sure I know what you mean by "500 knots worth of lift." On the second point, IAS instruments compare the dynamic pressure from the pitot tube with static air pressure. If these are the same you are not moving forward. If different, you are. Dynamic pressure by itself can't give you air speed since it depends on the ambient air pressure in addition to speed. 

What I meant was (for the layman) although your ground speed may indicate 500 knots, your aicraft is not experiencing 500 knots and could stall if the IAS is below the Vs speed.

It doesn't compare anything. It measures the speed at which the aircraft is experiencing (so to speek) which is why I used "feel". IAS is the most important airspeed as it determines if the aircraft is capable of performing at X V speeds. Ground speed will not tell you if you are about to stall. IAS will.

To be crystal clear, IAS is a direct measurement from the pitot tube. No calculations by computers or offsets of other calculated speeds.. IAS is used to calculate TAS which is not so important anymore with GPS ground speed indicators.

The pitot tube itself measures the difference between the static and dynamic or ram air pressure inside the tube and gives the aircraft an IAS reading (assuming its calibrated).

IAS is the speed of the aircraft through the air. If IAS is 200 knots and GS is 500 knots, your wing is not "moving through the air at 500 knots", Its moving through the air at 200 knots even though you are travelling 500 knots across the ground.

41 minutes ago, Ironhand said:

IDK. To my eye neither cockpit in the comparison video looked to be 30,000 ft AGL. So why are we even talking about this?

I never said it was.

We are talking about this so the OP (who's video I wasn't knocking) could take into account the many potential variables that he may not have been aware of when doing it again (which he said he would)

Why put effort into another video without understanding the potential factors involved. Then it leaves little question.

I'd argue that if both DCS and MSFS had all potential factors eliminated that they would look identical.

If they didn't look identical, then one of the applications is wrong. This detail is so easy to program that I highly doubt that either of them got it wrong, hence they will look the same.

They don't in this video because of some or all of the potential variables involved which we are trying to eliminate.

You also don't need to talk about this if you don't like, but you are here, so...

[unlikely_spider]

1 hour ago, Ironhand said:

IAS is the indicated speed through the air. If the GS is 500 knots, then your wing is moving through the air at roughly the same speed.

If there is no wind.

Edited February 26, 2023 by unlikely_spider

[sthompson]

10 hours ago, trevoC said:

What I meant was (for the layman) although your ground speed may indicate 500 knots, your aicraft is not experiencing 500 knots and could stall if the IAS is below the Vs speed.

It doesn't compare anything. It measures the speed at which the aircraft is experiencing (so to speek) which is why I used "feel". IAS is the most important airspeed as it determines if the aircraft is capable of performing at X V speeds. Ground speed will not tell you if you are about to stall. IAS will.

To be crystal clear, IAS is a direct measurement from the pitot tube. No calculations by computers or offsets of other calculated speeds.. IAS is used to calculate TAS which is not so important anymore with GPS ground speed indicators.

The pitot tube itself measures the difference between the static and dynamic or ram air pressure inside the tube and gives the aircraft an IAS reading (assuming its calibrated).

IAS is the speed of the aircraft through the air. If IAS is 200 knots and GS is 500 knots, your wing is not "moving through the air at 500 knots", Its moving through the air at 200 knots even though you are travelling 500 knots across the ground.

I never said it was.

Quoting from the Wikipedia page for indicated air speed: "IAS varies considerably from true airspeed (TAS), the relative velocity between the aircraft and the surrounding air mass." It does not mention "feel." I recommend it to anyone who, like me, might doubt that a wing "feels" anything. I also recommend the WIkipedia page for "Pitot-static system," which explains how IAS is measured and calculated (not necessarily by a computer). It's not that complicated and definitely relies on a comparison of static pressure with the pitot pressure. While it is possible that a pitot tube device also includes a static port used to detect static pressure, that isn't necessarily the case. The Wikipedia page reports that a separate static port is used in the Airbus A330 for example.

But we are off topic so I won't post more about this.

[Ironhand]

23 minutes ago, unlikely_spider said:

If there is no wind.

 

 That’s why I used the qualifier “roughly”.

[VR Flight Guy in PJ Pants]

I am sorry, please understand I just get a warning I cannot compare with other games. So I am not going to discuss the sense of speed here.

[Ironhand]

37 minutes ago, VR Flight Guy in PJ Pants said:

I am sorry, please understand I just get a warning I cannot compare with other games. So I am not going to discuss the sense of speed here.

Ahhh...yes. Forgot about that rule...which is too bad.

[trevoC]

3 hours ago, sthompson said:

." It does not mention "feel."

you are clearly taking my comments out of context.

you can keep doing that, but all was explained above and none of it is untrue.

[trevoC]

In an attempt to explain someone a concept without any prior knowledge, you use analogies. You may not like mine which is fine, but nowhere did I attempt to actually convey that an aircraft or its wing has feelings. I think you know this.

[Hiob]

2 hours ago, VR Flight Guy in PJ Pants said:

I am sorry, please understand I just get a warning I cannot compare with other games. So I am not going to discuss the sense of speed here.

It is meaningless anyway. Given that the scale is correct in both games (that means that a kilometer is a kilometer and a 100m wide building is a tenth of that), you are at the same altitude with the same reference objects (mind the term reference - like in frame of reference), the FOV is the same (this is very important) and no tricks like speed blur are used. The sense of speed is exactly the same. Speed is way divided by time. Notice how neither variable is dependent on a particular game (or any other environment), unless it's bend and cheated.

(One way for cheating would be actually going faster than displayed by the instruments. Which is something I can imagine for something like WT but not for any serious simulator).

My advice for the adrenaline junkies that feel the need for a more "thrilling" ride would be, increase your FOV and fly lower (L O W E R !)....

Edited February 26, 2023 by Hiob

[VR Flight Guy in PJ Pants]

Yeah, may be it is safer to compare DCS World sense of speed with Real Life^TM