Corner Velocity Discussion

[Shein]

so this article really changed the way I dogfight WVR in FC2: http://www.simhq.com/_air/PDF/air_097print.pdf

 

Not sure if you guys were aware of it, I did a quick search and couldn't find anything.

So in FC2, I was able to hold a tight turn at 340-350 knots, without losing any airspeed. I was even able to take on 8 mig 29's at once, and live (though it took a LOT of practice) at one point.

Now as I understand it, corner velocity increases with weight, and 340 is the speed for 70% fuel and no missile, full gun load. I also thought that the flight model was not changed from FC2 to FC3, but it seems I'm unable to turn at all in FC3 without bleeding an insane amount of energy. Either I turn so sluggish I might as well be prop driven to maintain speed, or I turn at 5-6 g's and I bleed airspeed so fast I'm down to 240 knots in 30 degrees of heading change. I can't seem to find a happy medium... so what am I doing wrong? Has the speed changed? has the flight model changed? is there something I'm missing?

Any veterans want to weigh in on this? :book:

also, any tips/tricks/observations related to WVR welcome, this is a topic I love talking about! :thumbup:

Edited December 15, 2012 by Shein
grammar correction

[159th_Viper]

Which aircraft? F-15?

[Shein]

Yessir

[159th_Viper]

All else being equal, the F-15 will always lose against the SU's and Migs in a low-and-slow turning fight. Exact numbers however escape me but I'm sure the budgie-drivers will be along shortly with data regarding optimum turning speeds.

 

That said, I'm sure there was a graph of sorts posted the other day if I am not mistaken - I'll see if I can find it.

[Shein]

Wow, really? I always thought the F-15 had the 29 outclassed in every way... I know the su is the end-all best slow turning dogfighter in FC3, but I really thought the eagle was in second place... I'd love to see that graph, viper!

 

Wow, awesome info kingsnake! That's the stuff I was looking for! Which one is the important one to look at, true or indicated?

And I tried applying less back pressure to maintain speed, but it resulted in a turn so slow I might as well have been flying straight - I was dead in seconds. That's what prompted me to start this thread!

But still, rep sent for all the awesome info!

[Kuky]

 

Per the FC3 Bug Thread "139 - MiG-29, Su-27 and Su-33 when in BVR mode Speed on HUD shown is TAS as opposed to IAS"

 

This means you only should get TAS once you go into STT.

Note: TAS is being shown when the "N" suffix is present. Currently I'm seeing in Nav Mode IAS, in BVR TAS (incorrect), and in STT TAS. Same in FC2

 

 

In BVR mode only there is "и" in the HUD (in Russian) which stands for "истинная скорость" - True Speed so this is not a bug. I thought it was too but seems it's how it is in the real thing.

 

All other modes (GND, NAV, CAC modes) show IAS

[Cali]

I haven't played FC3, but I know in FC2 in dogfigths it was Su-27 was the best, followed by the 15, the Mig-29 wasn't good at all.

[GGTharos]

Actually it's not the best info out there. The 'correct corner speed' is a matter of knowing the sustained g graph and instantaneous g graph. The STR one can be more important than the other, it depends. For the F-15, the 'correct corner speed' against a 29 or 27 is to stay above M0.6 where its STR is similar and its ability to recover speed superior, so you can counter superior ITR with vertical maneuvering (hopefuly).

 

There's no simple formula such as 'just hold your corner speed to win'. If you just do that, anyone with a bit of knowledge will get you. You ned to 'read' your opponent's energy state, you need to be able to figure out what his plane will do and what you can do about it, and you have to have this all planned out and figured out before it all happens. BFM is very complicated and most people never attain a good level of ability in it because it is a difficult subject with not that much info out on it.

 

You can know the corner speeds of all the planes, but so what? What do you do with them? That's the real trick.

 

Wow, really? I always thought the F-15 had the 29 outclassed in every way... I know the su is the end-all best slow turning dogfighter in FC3, but I really thought the eagle was in second place... I'd love to see that graph, viper!

 

Wow, awesome info kingsnake! That's the stuff I was looking for! Which one is the important one to look at, true or indicated?

And I tried applying less back pressure to maintain speed, but it resulted in a turn so slow I might as well have been flying straight - I was dead in seconds. That's what prompted me to start this thread!

But still, rep sent for all the awesome info!

[Shein]

i understand the f15 hud shows indicated, is there a way to make it show true?

also, playing around with it more, in sim, 400 knots seems to work a little better than 340, just an observation

[GGTharos]

No there isn't, and you don't need it. You can go my indicated mach number. As for what works 'better', that depends on your opponent and your weight.

[IvanK]

Well you can see the switch at TAS in the second Youtube (SU27) you listed at 1:51 with R27 it goes in STT and TAS pops up.

 

 

And in this one (SU27) at 4:16

http://www.youtube.com/watch?v=TaVlgZN_QnM

 

and this one (SU27) at 0:31

http://www.youtube.com/watch?v=H1i8pC6x5YY&playnext=1&list=PLF0988AA4C6025E9E&feature=results_video

 

So it would seen in RWS its IAS when you go to STT with missiles selected it goes to TAS in the SU27 anyway.

 

I am yet to see this happen on MIG29 though IRL videos.

Edited December 17, 2012 by IvanK

[lunaticfringe]

 

Thrust to Weight Ratio (higher is better)

MiG-29 - 1.08-1.1

Su-27 - 1.07

F-15 - 1.03

Su-33 - .83

 

True thrust to weight is variable based on altitude and current weight (which is why the plots are more important than raw numbers, since they tell the actual comparative tale at the specific numbers), but frankly- that's a pretty bogus T:W for the F-15C (if it's for the C at all):

 

The F-15C has a dry weight of just over 28k lbs. Internal fuel is short of 13.5k lbs. AIM-120s are less than 400lbs, whereas AIM-7s were like 540lbs on the button. AIM-9M/L were just below 200/ea, and the LAU pylon and wing root mount is less than a hundred. Even with the F100-100 (24k/ea), you're still talking a bare minimum, fully tanked, with a beefy pilot/gear combination just over 200 pounds, a T:W in the chocks of 1.06. Airborne, with half gas and a 4x AIM-9/AIM-120 or AIM-7 configuration, you're actually beyond a ratio of 1.25:1 depending on the thrust developed at the given altitude.

 

So like it's been said- it's all about the 'where', 'why', and 'how', as mentioned about the graphs.

 

That number looks more like the F-15E with an air to air configuration accounting for the conformals. Otherwise, it's a C with full pylons plus something like quarter-full external tanks.

[59th_Buncsi]

The MiG-29SMTs are able to show IAS, older versions arent.

[GGTharos]

It's accurate for some F-15 configuration. Generally speaking, you can expect the F-15C to have superior TWR to everything else when transsonic and for a lot of the subsonic and supersonic regime. It's not continuously superior over the entire flight regime, just like any other plane.

But the other thing that matters is who it runs into. Is that flanker still full of fuel, or is he running on fumes?

 

The FC-3 aircraft performances are tuned to very closely match the real life aircraft performance, so for the most part you are seeing correct dogfighting behaviour.

 

This is where I got the 1.03 number from for the F15C, I'm not sure how accurate it is though. I don't know for sure if any of the numbers I found web crawling are to be honest. Hopefully they are close to real life and what we have in FC3 for helping us better understand and utilize the differences in each fighters performance.

http://en.wikipedia.org/wiki/Thrust-to-weight_ratio

Edited December 17, 2012 by GGTharos

[59th_Buncsi]

I believe the above manual showing IAS on the HUD is for the MiG-29GT

 

German MiG-29s are other topic. After their modernization they had other radios, on their HUD were shown the frequencies and a lot of changes include the IAS on the left top corner of the HUD in knots not in km/h and altitude in feet instead of meters on the right top corner..

Edited December 17, 2012 by 59th_Buncsi

[59th_Buncsi]

Do you mean TAS or are the videos I found on youtube all from SMTs?

 

My bad: "The MiG-29SMTs are able to show TAS, older versions arent." This is the true statement.

[HiJack]

Using the new version of TacView i get about 15°/s turning at 400 knots. Fully loaded, 6*AIM120C, 2 fuelatanks (full) and white smoke canisters. Is that what I should get in the F-15C?

Edited September 13, 2016 by HiJack

[GGTharos]

At what altitude? Anyway you can just see how much G you can sustain, then you can directly compare to the F-15 STR chart if you have the correct GW.

[HiJack]

OK. I did a new test, same loadout (fully loaded)

ASL 1690 meter

TAS 754 Km/h

G 5.7

AoA 21.7°

TRate 15.5

TRadius 0.8 Km

 

Keeps this constant for several rounds.

 

Should I do the testing with a specific weight in stead?

 

EDIT: Had a look at the weight and its 24049 Kg starting the mission but i did some loops and stuff first :D

Edited September 13, 2016 by HiJack

[GGTharos]

Yes, use a specific GW ... let's go with 46000lbs, which is, IIRC 4 AIM-7, 4 AIM-9 + Centerline tank with a bit of fuel burned off IIRC ... all that matters is your GW (in lbs), your altitude (in feet) and your IMN (indicated mach number), and sustained G. The rest is not needed. Forget tacview, read it right out of the game while you are doing this.

[HiJack]

Thank you GG, will do some more testing with this.

[GGTharos]

You can compare with this, though this is the old engines (-100's instead of -220's) and pre-OWS (lower G-limit).

[HiJack]

It seams correct to me with a rate of turn 15.5 degrees per second at sea level. That ensures me I'm doing it right. Thanks for the chart.

Edited September 13, 2016 by HiJack

[Home Fries]

The question of Indicated Airspeed (IAS) versus True Airspeed (TAS) is complicated because the two are closely related and the performance curves depend on a number of variables, of which altitude is one.

 

Assuming standard temperature and pressure (i.e. 29.92" Hg at 15 degrees Celsius) and a standard rate of change of -.1" Hg and 2 degrees Celsius every 1000 ft, you will still have separate performance curves at sea level and at 10000 ft.

 

TAS is simply the aircraft speed through the air mass, not accounting for wind. IAS is the amount of air over the wings, which is necessary for lift (and therefore maintaining a sustained turn).

 

At sea level, IAS=TAS, so the amount of lift you generate to maintain your turn is also the amount of movement through the air mass that provides the numbers for the turn rate and radius.

 

As you increase in altitude, your IAS decreases for the same TAS. Therefore you may have the same TAS provide your turn rate/radius "footprint in the sky", but your IAS will be lower, indicating that your aircraft is generating less lift. You may need to increase your AoA to maintain the same lift, which puts you on a different diagram entirely.

 

BTW, having TAS and Groundspeed (GS) on radar returns is entirely accurate. Your radar can gauge the other aircraft's speed through the airmass, and the air data computer can provide the wind calculations to come up with GS. IAS on a radar return is unrealistic and less useful because 1) the radar can't tell what the other aircraft's pitot-static stystem is reading, and 2) speed through the air mass is what you really care about.

[Presing]

Gun fight it's not only about the Thrust to weight ratio and wing loading it's also a PILOT thing. In real life MiG and Su can win almost any time F-15 in dogfight but fighting against F-16 is different story (do not get me wrong F-16 have more chances to win from F-15). Dogfights are not numbers it's a dance you have to move and to watch your moves you made one wrong and your "partner" do not, you will be slammed. It's a how you will do with what you have. You have to lead a fight, if you do not lead that means you are "girl" and girls get f***d.