LO's F-15 vs. the F-15 Streak Eagle

[Weta43]

Is he swapping 1000 pounds for pylon drag on th LO F-15 against a clean reference flight ?

[Yo-Yo]

What I don't understand is what Yo-Yo's using to determine the intersection of 350KCAS and M0.9. From what I observed, he seems to be TLAR'ing to hit a precomputed KCAS at 5000ft altitude increments, since it looks a little fast.

 

http://forum.lockon.ru/attachment.php?attachmentid=10771&d=1178246839

 

Yes, Rhen, I used precomputed data. At the certaim altitude speed of sound is calculated then TAS then IAS. If it's less than 350 it's your next speed.

[Rhen]

Yo-Yo,

 

Are the HUD airspeed indications not in KCAS or the Mach readout in error? The Dash-1 numbers are based on instrument readings within the cockpit - specifically KCAS and Mach. The performance is based upon what's these instruments show. If the HUD airspeed indications are valid - showing appropriate KCAS and Mach, then these should be used for all airspeed benchmarks.

 

Using a computed TAS can cause the flight profile between the points to be in error - slightly slow or fast airspeed indications, which affect the slope.

 

Here's another chart of Time downrange vs Distance. This chart shows the slope of the climb. The slopes, as you've said do indeed match up fairly well, however, as you can see the slope isn't the whole picture.

 

If the LOMAC F-15 were performing similarly to the Dash-1, the altitudes that they arrive at should match HORIZONTALLY. That is, each aircraft should arrive at the same altitude with the same delta in time and distance. This would show a line similar to the Dash-1 slope, but skewed to the left/right a specific percentage.

 

It does not show this, as you can see from the chart. The altitudes don't match closely on the horizontal axis after 10,000ft. You can make the argument that low altitude performance of the LOMAC F-15 closely APPROXIMATES the real F-15, but above 10,000ft, you can see it diverges significantly (appears more than a 15% divergence in performance).

[SwingKid]

Hi Rhen,

 

I looked at your track, and agree with Yo-Yo - it seems that you have the throttle set a bit lower than we did. Nevertheless, it seems that we all finally have the same conclusion about mil-power high altitude performance.

 

I think it would be a good idea to have an optional key control to simulate the detent switch for afterburners - a sort of "afterburner toggle" as we had in Falcon 3.0. That way the player could slam the throttle full forward for mil power and not have to worry about starting the burners if he didn't want to.

 

I would also like a wingman command to disallow wingmen from using their own afterburners (to save fuel for long flights), but neither of these ideas received much of a response when I suggested them. What do you think?

 

Also, I'm looking again at the performance in max power near sea level. If I read the Dash-1 correctly, it seems to say that a 40,000 lb F-15 should take about 10 seconds to get to 5,000' in a max-power, 40-degree climb. I'm getting about 14 seconds. On the other hand, ground roll should be 1000 feet, and I'm getting about 1160 in Lock On. It still seems a bit underpowered at sea level to me, but I can't tell if it's by a lot or a little, and above 5000' things seem to agree again. Could you take a look and see if I'm doing anything obviously wrong?

 

http://www.ecf.utoronto.ca/~pavacic/lomac/f15maxcl.zip

 

Thanks in advance,

 

-SK

[Yo-Yo]

I think it would be a good idea to have an optional key control to simulate the detent switch for afterburners - a sort of "afterburner toggle" as we had in Falcon 3.0. That way the player could slam the throttle full forward for mil power and not have to worry about starting the burners if he didn't want to.

 

I would also like a wingman command to disallow wingmen from using their own afterburners (to save fuel for long flights), but neither of these ideas received much of a response when I suggested them. What do you think?

 

Also, I'm looking again at the performance in max power near sea level. If I read the Dash-1 correctly, it seems to say that a 40,000 lb F-15 should take about 10 seconds to get to 5,000' in a max-power, 40-degree climb. I'm getting about 14 seconds. On the other hand, ground roll should be 1000 feet, and I'm getting about 1160 in Lock On. It still seems a bit underpowered at sea level to me, but I can't tell if it's by a lot or a little, and above 5000' things seem to agree again. Could you take a look and see if I'm doing anything obviously wrong?

1. It is obvious... but it's a matter to discuss how to do it in the best way.

2. It's not useful because now AI already use AB only if they have lack of power during common maneuvers or in combat but if the leader uses MIL thrust wingmans have to use AB to join the formation, for example.

Or if the leader performs turn at MIL outer wingmans do have to use AB to maintain formation.

3. THe thrust is tuned to have dHe/dt and turn performance correct at SL. Do you really think 30 m is a value to discuss? Can it change something for a gameplay?

[Yo-Yo]

What if the flight lead knows his AI wingnuts have to catch up and slows down to wait for them to do so? Do they still use AB then?

 

Now it depends on distance between the leader and the wingman. If we prohibit to the wingman to use AB then the situation becomes possible when the relative speed is too low to rejoin the formation in acceptable time. For example, the distnce is 10 km and the relative speed is 20-50 kph...

 

If this speed difference is higher AI won't use AB or will use for a short time because it takes in account both the distance and the relative speed and even if the wingman uses AB for a few seconds he won't spend much fuel especially at high alt.

[GGTharos]

I think to get it to the level you're thinking IK they'd probably need to rip out and rewrite the whole AI.

[GGTharos]

Gotcha. I'm pretty sure ED is tired of old AI code ... :)

[SwingKid]

Regarding: a command to enable/disable afterburner

 

1. It is obvious... but it's a matter to discuss how to do it in the best way.

 

I understand. It may not seem intuitive to model detent switches by a toggle key, but based on Falcon 3.0 experience, this method worked well and "felt" good. Much more precise and controllable than the clicking detent "bumps" on my HOTAS Cougar throttle, for example, or trying to find the afterburner setting on a regular throttle without reference. I put markings on my throttle for the afterburner position, but that's still not enough, because the position changes in Lock On, depending whether the throttle is being increased or decreased.

 

 

Regarding: a command to disallow wingmen from using afterburner

 

2. It's not useful because now AI already use AB only if they have lack of power during common maneuvers or in combat but if the leader uses MIL thrust wingmans have to use AB to join the formation, for example.

Or if the leader performs turn at MIL outer wingmans do have to use AB to maintain formation.

 

Actually, this is why I think it is useful. If I fly in a fuel-restricted MiG-29 to bomb a distant target, then I want my wingman to stay "roughly" in formation with me on the way to the target, but not so strictly that he's using afterburner to try and match my precise maneuvers. On its own, the AI seems to use afterburner for every 500-meter climb, regardless the distance between the waypoints of the climb. I would like the ability to restrict him from using the afterburner during the ingress/egress, and then allow him to use it in combat. Too often when we get to the combat zone, my wingmen are trying to land and refuel - at the same enemy airbase that we're supposed to attack.

 

 

Regarding: ground effect

After some more testing and research, I'm surprised - AMAZED - to discover that there IS a ground effect in Lock On, both for SFM and AFM - and, it even seems to have the correct value!

I have to wonder, then, how none of us managed to notice it before - even when looking for it! It must be another of those, "you can only sense it with your butt" things.

 

Congratulations..

 

-SK

[TucksonSonny]

Regarding: ground effect

After some more testing and research, I'm surprised - AMAZED - to discover that there IS a ground effect in Lock On, both for SFM and AFM - and, it even seems to have the correct value!

I have to wonder, then, how none of us managed to notice it before - even when looking for it! It must be another of those, "you can only sense it with your butt" things.

 

Congratulations..

 

-SK

 

Real low flyers like me have noticed it! :D

[hitman]

I fly lower than some small children and I never noticed this...

[GGTharos]

Real low flyers like me have noticed it! :D

 

... he didn't mean the one where you explode if you hit the ground ... ;)

[TucksonSonny]

I fly lower than some small children and I never noticed this...

 

Try to land at very low angle you will notice it!

 

"Ground effect, often described as a 'cushion', is thought to be an increase in air pressure which occurs below a wing when it comes into close proximity with the ground. Ground effect begins to be noticeable (to both the pilot and an onlooker) when the aircraft is within 1-1.5 times the length of its own wingspan from the ground. Ground effect, however, only becomes extremely pronounced, where lift can momentarily increase by as much as 40%, when the plane is within about half its wingspan distance from the ground."

 

 

Occasionally I notice the following ground effect with my over loaded 25T:

 

"Ground effect during take-off is thought to be a cause of many aircraft accidents. A small plane loaded beyond gross weight capabilities may be able to take off under ground effect, thanks to the 'artificially' low stall speed due to the decreased induced drag. But it may not be able to climb beyond a certain point. Once the pilot climbs out of ground effect wingtip vortices will form, the wings will stall, and the aircraft will suddenly descend - usually resulting in a crash" (this happened multiple times to me :D ).

[SwingKid]

"Ground effect, however, only becomes extremely pronounced, where lift can momentarily increase by as much as 40%, when the plane is within about half its wingspan distance from the ground."

 

For Lock On's SFM F-15C, the lift bonus is much smaller - only 5%, one-third wingspan (3 meters) above the ground. However, for the F-15, this seems to be accurate (see Fig. 8 ):

http://www.nasa.gov/centers/dryden/pdf/88337main_H-1999.pdf

 

If your sink rate to the runway is only about 100-200 feet per second, then you should notice it. I think most of us usually sink much faster though, and plough right through it.

 

-SK

[Prophet]

Regarding: a command to enable/disable afterburner

 

I understand. It may not seem intuitive to model detent switches by a toggle key, but based on Falcon 3.0 experience, this method worked well and "felt" good. Much more precise and controllable than the clicking detent "bumps" on my HOTAS Cougar throttle, for example, or trying to find the afterburner setting on a regular throttle without reference. I put markings on my throttle for the afterburner position, but that's still not enough, because the position changes in Lock On, depending whether the throttle is being increased or decreased.-SK

 

SK, I have my cougar setup a bit different, I only have the AB detents. What I did was run the throttle range program, and then use the value in there and wrote the profile that between a certain range, it equals 100% Mil. It took a bit of tweaking to get the values right, but I will post what I got if you want, and then you can adjust as needed.

 

The interesting thing, is at 100% Mil, the AB lights are on, only on F15. But no flame. All other planes dont have the AB lights on.

[Kuky]

If your sink rate to the runway is only about 100-200 feet per second, then you should notice it. I think most of us usually sink much faster though, and plough right through it.

 

I think you must have made a typo here... decending at 100ft/s or approximately 30m/s when trying to land will result in a crash :thumbup:

 

Just before wheels touch the runway your sink rate should be very low, probably about 1-2m/s

[GGTharos]

I'm sure he meant per minute :)

[aimmaverick]

Any final comment from ED regarding ingame f-15 (su-27/33) performance?

[GGTharos]

Have you read the thread?

[SwingKid]

Have you read the thread?

 

I love it when GG responds to noobs. So mercilessly quick, so pitilessly unhelpful. :)

 

for aimmaverick:

http://forum.lockon.ru/showthread.php?p=326200#post326200

 

-SK

[GGTharos]

SK is the good cop ;)

[RvEYoda]

Lockon f-15 with no fuel tanks & full internal fuel: You'll mantain a 15-20 degree climb at angels 10-15.......if you're lucky ^^^^

[S77th-GOYA]

<forum.lockon.ru>

 

You must spread some Reputation around before giving it to ruggbutt again.

 

:doh:

[aimmaverick]

Have you read the thread?

 

He only mentions slight improvemnt for f-15 no comment about su-27/33 which suffer from the same problems. Not to mention other AI planes which are supposed to get the same FM dynamics as player controled jets. I hope they will not have trouble climbing and cruising at altitude without using afterburner.

[GGTharos]

The Sukhois will have to be looked at as well, I think after this FM has been shown to have this deficiency Yo-Yo will be able to quickly check if the 27/33 FM's conform.

 

As for the AI FMs, I wouldn't worry about'em for now.