Some questions for F-15 connoisseurs

[Skall]

Been spending some time learning the F-15 for the first time and I have a few questions I can't find answers for even in ye olde Google. I'd appreciate some help here.

 

1. At what speeds is it safe to drop gears, flaps and airbrakes? Since the manual says final should be done at 170 knots, I wait until 170 to drop gears and flaps but then have to make a lot of throttle adjustments to get back up to 170. It would be nice to know what the max speeds are so I can configure the plane and have the gears and flaps help me bleed off speed.

 

2. In the hog I'm used to using ~40% air brakes turning to final and then full air brakes on touch down. Are airbrakes ever used for landing on the F-15 and, if so, when should I employ them?

 

3. What is the F-15's most fuel efficient cruise speed/power/RPM?

 

4. The P button does not seem to launch the parachute to slow the plane down on the runway. Does the F-15 just not have one? (Don't feel like I need it since the simple flight model makes it possible to land on a dime but just curious)

 

5. It seems to be impossible to turn on the Doppler radar while on the ground. Was trying to study the thing but had to resort to active pause in the air to play with it. Is there a specific reason why the F-15 can't use the radar while on the ground?

 

6. Some details of the Doppler radar escape me. I get that the radar is a cone and points in the direction of the TDC and that the longer the range, the wider the cone. However there are times when the bugged plane is right in front of me, say 13NM ahead, and the square around the plane begins to blink and I lose radar lock. The horizontal scan zone is 600 so it sweeps the entire cross section, the vertical scan zone has a range of 0-9 (target in the mission editor is set to orbit at 7000 and to not respond to threats) so the target's altitude is not a problem yet I sometimes lose the lock and sometimes don't. I can't tell what the determining factor is.

 

7. Tied to 6, there are times when the bugged target's square is well to the left or right of the steering dot, making it impossible to maneuver to a high Pk heading while maintaining a lock. Is there something that can be done about this or that's just a fact of life?

 

8. Wikipedia shows some incredible ranges for the AIM-120 (50+ NM) yet I can never seem to get a green (red?) light for firing until I'm within ~10 NM of my bugged target. How is it possible to get a lock and fire an AIM-120 from 50+ NM away? Do I need a massive altitude and speed advantage?

 

9. When slewing the TDC on the VSD, I noticed the vertical scan zone numbers change even though the scale (10, 20, 40, etc) hasn't changed. If I move the TDC 3/4 of the way up on the 40 NM scale, does that mean my radar will only pick up targets from 30 NM away? Or is it just letting me know the height of the scan cone at that distance?

 

10. Is there ever any reason to use an AIM-7 over an AIM-120 assuming real-world costs are not a factor? Seems like for active radar missiles, the 120 is the clear choice and for IR its the 9.

 

Thanks for the help.

[Exorcet]

Been spending some time learning the F-15 for the first time and I have a few questions I can't find answers for even in ye olde Google. I'd appreciate some help here.

 

1. At what speeds is it safe to drop gears, flaps and airbrakes? Since the manual says final should be done at 170 knots, I wait until 170 to drop gears and flaps but then have to make a lot of throttle adjustments to get back up to 170. It would be nice to know what the max speeds are so I can configure the plane and have the gears and flaps help me bleed off speed.

In FC3, 250 KIAS

 

2. In the hog I'm used to using ~40% air brakes turning to final and then full air brakes on touch down. Are airbrakes ever used for landing on the F-15 and, if so, when should I employ them?

You can use them or not, either keep them deploy while on final to keep engine RPM up in case of an aborted landing or save them for touchdown.

 

3. What is the F-15's most fuel efficient cruise speed/power/RPM?

From a half guess half experience from flying the F-15 forever, I usually go 90-95% RPM (450-500 TAS) at 30,000 ft. Part of that isn't for efficiency but combat effectiveness though.

 

4. The P button does not seem to launch the parachute to slow the plane down on the runway. Does the F-15 just not have one? (Don't feel like I need it since the simple flight model makes it possible to land on a dime but just curious)

No chute.

 

5. It seems to be impossible to turn on the Doppler radar while on the ground. Was trying to study the thing but had to resort to active pause in the air to play with it. Is there a specific reason why the F-15 can't use the radar while on the ground?

Don't know.

 

6. Some details of the Doppler radar escape me. I get that the radar is a cone and points in the direction of the TDC and that the longer the range, the wider the cone. However there are times when the bugged plane is right in front of me, say 13NM ahead, and the square around the plane begins to blink and I lose radar lock. The horizontal scan zone is 600 so it sweeps the entire cross section, the vertical scan zone has a range of 0-9 (target in the mission editor is set to orbit at 7000 and to not respond to threats) so the target's altitude is not a problem yet I sometimes lose the lock and sometimes don't. I can't tell what the determining factor is.

It might be beaming/notch. When the velocity of the target relative to you is near zero, it is difficult for the radar to track. Combine this with a look down situation where the target hides in the reflection of the radar off the ground, and lock loss might be inevitable.

 

7. Tied to 6, there are times when the bugged target's square is well to the left or right of the steering dot, making it impossible to maneuver to a high Pk heading while maintaining a lock. Is there something that can be done about this or that's just a fact of life?

The radar cone is pretty big, this shouldn't be too common. If it is, then they're probably so close that the missile won't run out of energy chasing them (but you might need to watch for Rmin).

 

8. Wikipedia shows some incredible ranges for the AIM-120 (50+ NM) yet I can never seem to get a green (red?) light for firing until I'm within ~10 NM of my bugged target. How is it possible to get a lock and fire an AIM-120 from 50+ NM away? Do I need a massive altitude and speed advantage?

Range is complex. You can probably shoot at 50 nm if you're at say 50,000 ft at Mach 2. The higher the missile, the less drag on it. The faster you go, the faster the missile goes (most of the time).

 

The target also plays a huge role. If it's coming head on, range will be high, if it's maneuvering, range will be greatly reduced.

 

9. When slewing the TDC on the VSD, I noticed the vertical scan zone numbers change even though the scale (10, 20, 40, etc) hasn't changed. If I move the TDC 3/4 of the way up on the 40 NM scale, does that mean my radar will only pick up targets from 30 NM away? Or is it just letting me know the height of the scan cone at that distance?

It's telling you the height of the cone at the distance the TDC is looking at currently.

 

Moving the TDC or changing range never changes where the radar is looking (except when in narrow azimuth mode, then TDC controls left and right field of view).

 

10. Is there ever any reason to use an AIM-7 over an AIM-120 assuming real-world costs are not a factor? Seems like for active radar missiles, the 120 is the clear choice and for IR its the 9.

 

Thanks for the help.

You can control exactly where the AIM-7 goes, so if you're shooting at a MiG in a dogfight with your wingman, your AIM-7 will only go after the target you lock. If you use the AIM-120 and lose lock, the 120 might chase your wingman thinking it's a target.

[kontiuka]

For #5, I'm just guessing it's a safety precaution because of the amount of radiation it pumps out. Don't want to fry your ground crew.

[mvsgas]

This might help in some of those question

http://www.scribd.com/doc/94648410/TO-1F-15A-1-Flight-Manual-USAF-F-15-Series-A-B-C-D-Block-7-and-Up-Change-5-01-Mar-1986

[GC1993]

2. In the hog I'm used to using ~40% air brakes turning to final and then full air brakes on touch down. Are airbrakes ever used for landing on the F-15 and, if so, when should I employ them?

 

The use of airbrakes for landing is flexible, there's no set procedure or instructions that says you MUST deploy airbrakes for touchdown.

 

I'll use airbrakes on the approach if I'm coming in too hot, apart from that the flaps usually give enough drag to limit the speed from creeping too high and you just prevent the speed going too low with gentle throttle moderation.

 

I use the airbrakes for touchdown quite frequently, only because I've seen eagles do it in real life. In the final 5 or so seconds before touchdown, you'll obviously ease the flare to get the smoothest touchdown possible - this sometimes causes you to hover just a foot or so above the tarmac; deploying the airbrake in the final few seconds usually lets you finally drop those last few inches nice and smoothly.

[104th_Maverick]

#5

 

You can turn on your radar on the ground by entering into vertical scan mode (default 3) then going to Air Search mode (default 2)

 

#10

 

Aim 7 is sexier! Read up about FLOOD mode in your FC3 manual!

 

Good answers Exocet!

 

Mav

[lxvanwyk]

In real life safety gates are often built into combat aircraft's weapon systems. One of these usually will include some form of weight on wheels cut "switch" for several systems including most probably the radar and weapon release kill switches. I haven't checked whether u can fire weapons (missiles, bombs and cannon) on the ground. I know in older generation fighter aircraft the pickle release would be killed by weight on wheels but not the cannon trigger. This was to be able to do accuracy alignment on the cannon while on the ground.

[104th_Maverick]

No, you cannot fire any weapons on the ground until the WOW is no longer registered

[lxvanwyk]

;1857185']No' date=' you cannot fire any weapons on the ground until the WOW is no longer registered[/quote']

 

Well there you go.......Ta Mav.

[Skall]

Thanks a lot for the info, guys, especially Exorcet. Good details there. At work ATM but I'll be on later today with a few more questions and comments. Been doing some research on the missiles and tactics and a few blanks came up. I'm surprised at how detailed the F-15 systems are in DCS even with the simplified model. Tons of training must go into them so that you can keep your cool while using all of this stuff in the middle of combat.

[Skall]

Thanks again for the help. The radar lock loss due to notching makes sense. I put the test targets on orbit and after some more testing I realized I was losing lock when their flight vector was perpendicular to mine. Interesting seeing the effect.

 

A couple more questions if you don't mind...

 

1. I enter NAV mode by pressing the 2 key. I can cycle through my mission way points just fine (too bad there is no "back" button like the A-10) but there are two differences that don't correlate to the manual: the HUD waypoint indicator is not a cross but a straight line. It doesn't seem to pick up elevation data from the waypoint. Also, only the vertical ADI yellow bar moves. The horizontal bar always remains locked in the bottom position even when I know I'm flying at the proper altitude. Additionally, the bottom left of my HUD does not show G-load. Instead, it always shows two numbers separated by a space. First number seems to change with pitch but does not correspond to the pitch ladder. The second number seems stuck at 90. What are these numbers and why am I not seeing G-load instead?

 

2. My HUD symbology for launching 120's also looks wrong. On the bottom left, instead of seeing 120C X where X is the number of missiles, I see A2C LM and that doesn't change regardless of how many missiles I have. I also don't see G-load like the manual says I should.

[Skall]

Testing things out more, I realize the manual is definitely not in sync with the sim.

 

I made a test mission with a load out of 2 AIM-120s, 9s, and 7s. I gave myself infinite ammo so I can mess around.

 

The manual says the 6 key should take me into VISUAL mode for the 120's. With a 120 selected, when I press the 6 key, it switches me to the AIM-9 and I can hear the growl.

 

The manual says the 2 key should put me into LRS mode. However, I seem to go into LRS mode just by turning on the radar. Pressing the 2 key puts me into VISUAL mode (not the 6 key).

 

I also can't seem to exit VISUAL mode and go back to RWS unless I go to NAV mode (1 key). However, NAV mode turns off the radar and I have to press I again to go back to RWS.

[GC1993]

I'm at work so I can only reply to the few things I know off the top of my head.

Firstly, you're right in that the manual is outdated - it is for the Flaming Cliffs 1 or 2 F-15C, and ED have since made realistic changes to their FC3 aircraft, they just haven't synchronised the manual with it.

 

NAV mode should be "1", key, and pressing it repeatedly toggles navigation mode and ILS landing mode. The HUD waypoint was a cross in FC2 but they corrected it for FC3. The vertical line is the same indication pretty much as is on your HSI - if it's left of your TVV then you need to make a course correction to the left. If it's to the right then vice versa. It's not how it used to be in FC2 where it would hang to the far side of the HUD if you had to make a long turn to fly to your waypoint and adjust it's position depending on how close/far you are to facing the steerpoint. It's either slightly left, slightly right, or in the middle of the TVV in FC3.

 

To be honest I don't even use my HUD for navigation as it's not precise, I use the HSI on the dash, along with the distance indicater in miles just above it.

 

As for weapon modes, the "6" key enteres boresight mode for the AIM-9. There isn't really a general visual mode for the AIM-120C per say. If you're within visual range and will no longer be using your radar, typically you'll want either the "4" key which is a boresight for the selected missile (works great for the 120 if you're looking toward the general direction of the bandit < 10 miles, it will lock them up straight away and give you the launch cue with all neccesary symbology). Alternately, press "3" to enter vertical scan mode, which is used frequently for tight turns with an AIM-9 in a merge but can also be used to find targets with a 120 if you bank 90 degrees and maneuver in both directions until the radar picks him up for you (again if you're in range and facing relatively near the target).

 

If your current key behaviour is causing you to enter the wrong weapon modes then something's been shuffled in your control mapping, and you need to re-assign them to default.

 

That's all I can answer off the top of my head I'm afraid.

Edited September 4, 2013 by GC1993

[Skall]

Thanks GC, I appreciate the help. Good to know that there are a few things out of sync and not just me.

 

Going to do more test runs to keep figuring this out. I looked at my keyboard mappings (which I haven't touched) and I have the following mapped to the 1-6 keys;

 

1. Navigation Modes

2. Beyond Visual Range Mode

3. Close Air Vertical Scan Mode

4. Close Air Combat Bore Mode

6. Longitudinal Missile Aiming Mode/FLOOD mode

 

Which seems right. I did make a mistake due to misunderstanding on my previous post. It appears that going into BVR mode with a 120 will also put you into VISUAL mode and allows you to acquire a target via the radar or through the FOV if within close distance.

 

I'm still not certain how I can get better range out of the missile. I set a target at 5000 ft and I climbed to 30000 40 NM away and the best I got was 17 NM range before receiving the "shoot" notification. Going to spend some quality time with the manual today.

[GC1993]

Those key commands are correct, so not sure why yours seem to command elsewhere.

 

I'm not an expert on getting the best out of BVR engagements, so really I can only re-enforce what others have suggested.

 

-Have a good altitude advantage, though try to stay out of the contrail altitude range (somewhere between angels 26 and angels 40 I believe) or else you can be spotted from well over 100 miles away.

 

-Fine-tune your radar settings (scan zone etc) so that all of your radar energy is focused on the bandit, you don't want to risk breaking lock.

 

-Engaing a bandit who is hot will ALWAYS give you a launch cue at a further distance due to the closure rate, so don't worry if you're struggling to get a 120 launch cue if he's on the run 15 miles away. (I've even not had a lock 9 miles away when he's cold and I've been lower than him).

 

Choose your jammer timing carefully. Too far away and they'll see you way before their radar would normally pick you up and can HOJ. Too close and it has no effect on the radar guidance.

 

I learnt BVR the hard way by going on the Black Sea Redemption server online - you get absolutely SMASHED about on that by the pros but it teaches you useful tactics.

 

EDIT: even if you DO get a lock & launch cue at 30+ miles, you don't want to launch unless its a cargo plane or civil plane that will get no missile warning and continue on course. Anything else will get a launch warning and maneuver HARD - the missile will have burned out it's motor after 10-15 seconds or so (don't know how long exactly) and so for the rest of it's journey it will bleed off a lot of energy every time it's target makes another adjustment (missiles fly to meet a target remember, not chase it). Personally I wouldn't launch till 20 miles or less and even then only if I had a height advantage, because the slammer just slows down too much when it's trying to fly to a maneuvering target on 0 energy. This is one of the area's where the flankers will batter you online - the R-27ER stays on burn for longer and has better range so by the time you get your launch warning in the eagle and start to maneuver, it's already pretty close to you and has a good chance of hitting you unless you use terrain as defence.

Edited September 4, 2013 by GC1993

[Skall]

Thanks for the tips, I'm taking notes on some of these things.

 

Spent more time experimenting and here's what I found out.

 

1. Despite the word VISUAL appearing on the bottom right of the HUD while having an AIM-120 selected and pressing the 2 key, it operates in LRS/BVR mode. I can bug targets from far away, shoot at 10+ mile distances (was able to get one at 17 with enough altitude) and functions like the LRS mode in the manual says. Getting close and personal does not get me a lock automatically and any shots even up close go ballistic if I have not bugged a target.

 

Either the word VISUAL is a bug or just extremely misleading. There's nothing visual about operating in this mode.

 

2. Not depicted anywhere in the manual, AIM-9's in boresight and vertical scan mode can be fired with or without the radar on. If the radar is on, the radar will assist the lock. If the radar is off, the missile seeker is used to acquire the lock. The HUD shows an extra circle when firing from these modes while the radar is on.

 

3. Pressing the 6 key while having an AIM-120 selected will switch you to an AIM-9. Pressing the 2 key while having an AIM-9 selected will switch to an AIM-120.

 

4. Caged/Uncaged mode for AIM-9 (6 button) turns off the radar but the radar can be turned back on while in that mode.

 

5. With the radar off on caged/uncaged mode of AIM-9, pressing 2 will switch to AIM-120 with the radar on. However, pressing the change weapon [D] button to switch to an AIM-120 manually will keep the radar off.

 

6. 80% of the bottom left and bottom right corners of the HUD for all modes across all three missile types look nothing like what's on the manual. I have very little idea what the corners of my HUD are trying to tell me. I even see some XYZ SEC indicators that count down to something. At first I though it was the time for the missile to hit but most of my missiles where hitting well before the count down finished. Some as high as 13 seconds remaining.

[Frostie]

Thanks for the tips, I'm taking notes on some of these things.

 

Spent more time experimenting and here's what I found out.

 

1. Despite the word VISUAL appearing on the bottom right of the HUD while having an AIM-120 selected and pressing the 2 key, it operates in LRS/BVR mode. I can bug targets from far away, shoot at 10+ mile distances (was able to get one at 17 with enough altitude) and functions like the LRS mode in the manual says. Getting close and personal does not get me a lock automatically and any shots even up close go ballistic if I have not bugged a target.

 

Either the word VISUAL is a bug or just extremely misleading. There's nothing visual about operating in this mode.

 

2. Not depicted anywhere in the manual, AIM-9's in boresight and vertical scan mode can be fired with or without the radar on. If the radar is on, the radar will assist the lock. If the radar is off, the missile seeker is used to acquire the lock. The HUD shows an extra circle when firing from these modes while the radar is on.

 

3. Pressing the 6 key while having an AIM-120 selected will switch you to an AIM-9. Pressing the 2 key while having an AIM-9 selected will switch to an AIM-120.

 

4. Caged/Uncaged mode for AIM-9 (6 button) turns off the radar but the radar can be turned back on while in that mode.

 

5. With the radar off on caged/uncaged mode of AIM-9, pressing 2 will switch to AIM-120 with the radar on. However, pressing the change weapon [D] button to switch to an AIM-120 manually will keep the radar off.

 

6. 80% of the bottom left and bottom right corners of the HUD for all modes across all three missile types look nothing like what's on the manual. I have very little idea what the corners of my HUD are trying to tell me. I even see some XYZ SEC indicators that count down to something. At first I though it was the time for the missile to hit but most of my missiles where hitting well before the count down finished. Some as high as 13 seconds remaining.

1. Visual means just that, if you see the bandit visually you maneuver your aircraft to get the bandit in the bore sight, then fire an AIM-120, in theory the FCS will know you're using this mode so the missile will immediately use its own radar to find the target.

 

2. the missiles seeker needs to see the target before you launch this is achieved either by the radar slaving to the seeker or you not using radar and putting the reticule on the target visually. Either way the missile once locked on will track the same.

[Skall]

1. Visual means just that, if you see the bandit visually you maneuver your aircraft to get the bandit in the bore sight, then fire an AIM-120, in theory the FCS will know you're using this mode so the missile will immediately use its own radar to find the target.

 

2. the missiles seeker needs to see the target before you launch this is achieved either by the radar slaving to the seeker or you not using radar and putting the reticule on the target visually. Either way the missile once locked on will track the same.

 

1. That's just it. When I use mode 3 or 4 (vertical scan and boresight), it works as the manual states: I get up close, put the target on my boresight or just above it if vertical and I get a lock then fire away. However, mode 2 is clearly for LRS yet my HUD says VISUAL despite not being able to get a lock by putting targets on my boresight up close but being able to lock and shoot from 15nm away.

 

2. Makes sense and I realized it. Just pointing out the manual never mentions it.

[Exorcet]

The AIM-120 is basically always in visual mode. Mode 2 is for BVR, but if you happen to spot a MiG crossing your HUD that you don't see on the radar, you can just a 120 at it if it's in the circle and there is a good chance that you'll kill it.

 

You can do this even if your HUD and radar are completely gone.

 

Be careful when looking for consistency with the manual, it's in need of an update. Use it as a rough guide, but always check it with a test flight or something.

[Skall]

The AIM-120 is basically always in visual mode. Mode 2 is for BVR, but if you happen to spot a MiG crossing your HUD that you don't see on the radar, you can just a 120 at it if it's in the circle and there is a good chance that you'll kill it.

 

You can do this even if your HUD and radar are completely gone.

 

Be careful when looking for consistency with the manual, it's in need of an update. Use it as a rough guide, but always check it with a test flight or something.

 

Did not know that about the 120. Thanks. I'll keep in mind the fact that the guide has not been updated for FC3.

[Pilotasso]

errr... that was before missile AFM, it was able to cope with the turn, right now, if a target crosses your HUD visually, the missile is likely to just overshoot it, its manoeuvrability is low. Its a tad weak at close ranges right now.

[Skall]

errr... that was before missile AFM, it was able to cope with the turn, right now, if a target crosses your HUD visually, the missile is likely to just overshoot it, its manoeuvrability is low. Its a tad weak at close ranges right now.

 

Could explain why my testing made it seem to me like the 120 did not have an active seeker up close. The missiles seemed to leisurely stroll by instead of chasing any targets.

[Pilotasso]

It seems they have a 1-2 second where they go straight, I believe it is intended to simulate as a safety measure to prevent the missile from manoeuvring or arming too close from the launcher but ended having undesirable overshooting effect instead.

 

The real missie can indeed deal with close range threats. Take a look on this 1992 AIM-120A HUD tape of a kill. Cant be more than 2-3 miles head to head.

 

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