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I bet I've watched a thousand IRL F-15C landings and never seen one behave like the DCS F-15C. I guess you have to remember that it is a FC3 aircraft and doesn't get much love. Even taxing the aircraft is ridiculous. 

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10 minutes ago, kdrum60 said:

I bet I've watched a thousand IRL F-15C landings and never seen one behave like the DCS F-15C. I guess you have to remember that it is a FC3 aircraft and doesn't get much love. Even taxing the aircraft is ridiculous. 

Interesting. What's different concerning the landing and ridiculous about taxiing if I may ask?

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My guess would be how a minor cross wind effects the F-15C's path as it rolls down the taxiway or on landing roll out. Now, before you try to give me a lesson on the F-15C's aerodynamic properties and all, please be advised that I had a retired USAF Lt. Col F-15C pilot in my sim a few years ago and he said that it did not behave correctly while taxing or during take off and landing and that the in-flight properties were close but could use some refinement. I have a couple pages of notes somewhere in my sim room, I'll have to look for them.

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Have you tried to deflect ailerons into the wind? I do not know about real one and whether FC3 F-15 matches it, but in the game 25kts xwind rollouts are uneventful, except aircraft doesn't want to aerobrake.

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I have landed other fighters and none give me problems except for the F-15. Landing the bird is not the problem, keeping it on the runway after landing is giving me headaches. What am I doing wrong??

 

Not much to go on here but I will take a Stab at it. With "Flaps & Gear DOWN" using the lowest approach angle possible. At Threshold Flare & Maintain 22 AOA while reducing speed. On rollout keep the Nose at 22AOA & use your RUDDER to Steer. When rolling speed drops below 100Kts the Nose will Drop, only now use Steering & Brakes. Airbrake as you see fit. Depending on Weight your Landing speed, 150Kts Light or 180Kts Heavy. Don't forget the F15-C has Brittle Landing Gear, so SMOOTH is a Premium or Bent & Broken "Gear&Tires" will follow. Good Luck & Hope this Helps.

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I suppose the O.P. is refering to the tendency the F-15C has to start drifting left and right (sometimes briskly), at the tarmac when aplying the wheel brakes.

 

This drift tendency, can eventually cause the airframe to roll and the wings will collide with the tarmac.

 

 

 


Edited by Top Jockey

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5 hours ago, kdrum60 said:

My guess would be how a minor cross wind effects the F-15C's path as it rolls down the taxiway or on landing roll out.

You didn't mention that you were talking about xwnd ops. These are indeed way off on the DCS F-15.  


Edited by bbrz

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On 12/6/2020 at 12:09 PM, bbrz said:

You didn't mention that you were talking about xwnd ops. These are indeed way off on the DCS F-15.  

Yep, the xwind effect on ground does seem weird. Either that or my technique / controls setup was off.  It's been a while.

I did the overhead at 1500 ft. agl.  Everything looked fine until the touchdown. The upwind side main gear came up then dropped. I didn't bounce (checked in F2 view). The aerobraking wasn't too bad although at one point I pulled too much and almost scraped the tail. The fun started when the nose gear came down. I was holding some right rudder during aerobraking to prevent weathervaning into the wind and didn't ease up just before the nose dropped. 

The wind was only 12 kts, but it was almost directly from the side.

 

 

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Just a case of trying to avoid hitting the ground too hard 🙂

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  • 3 weeks later...

Yeah, the F-15C is a simplified flight model (as well as other FC3 flyables) so aerobraking during landing rollout doesn't seem to produce anything.

 

Wheelbraking is funny, I can't say if it works at all, keeping the W button pressed doesn't really slow You down in landig rolls and doesn't prevent rolling if you throttle up to ~90% RPM. Differential braking (left and right wheelbrakes) cause major oscillations. Wheels tend to lock up so you skid around like crazy.

 

   

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Perhaps I'm doing something wrong by keeping the AoA at 10° during landing rolls but my touch down to full stop time and distance seems equal as without aerobraking. Perhaps aerobraking ain't that effective as we might expect it.

 

I've witnessed F-15E doing a wheelie during landing roll, she was barely moving down the runway but pilot had a nose wheel up for 20 something seconds, playing with AoA as he liked it. Definitely much slower than 100TAS when DCS script drops F-15C nose. So that's why I still believe that fight model is heavy scripted / simple.

 

Check this vid at 3:43, it was closest I can find to what I saw live but camera footage here doesn't represent how slow they really roll. On the other hand here's the wet runway during airshow so pilots did no crazy stunts in this video.

 

 

 


Edited by Vekkinho
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40 minutes ago, Vekkinho said:

Perhaps I'm doing something wrong by keeping the AoA at 10° during landing rolls but my touch down to full stop time and distance seems equal as without aerobraking. 

 

I've witnessed F-15E doing a wheelie during landing roll, she was barely moving down the runway but pilot had a nose wheel up for 20 something seconds, playing with AoA as he liked it. Definitely much slower than 100TAS when DCS script drops F-15C nose. So that's why I still believe that fight model is heavy scripted / simple.

 

Yes, you are doing it wrong. 10° is too low.  13° is the minimum and 15° the maximum.  14° is being used in the performance charts.

The higher the pitch attitude, the closer the wheels are to the CG and hence the easier it is to keep the nose up.

 

Have you measured the distance or do you only have the impression that the distance is equal? Did you apply the wheelbrakes while aerobraking?

 

CG has a large effect on the F-15 concerning the aerobraking capability and comparing the C with the E is in this case almost like comparing apples and oranges.

 

The CFTs on the C are moving the CG up and aft and are thereby increasing the aerobraking capability.


Edited by bbrz

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1 hour ago, Vekkinho said:

Perhaps I'm doing something wrong by keeping the AoA at 10° during landing rolls but my touch down to full stop time and distance seems equal as without aerobraking. Perhaps aerobraking ain't that effective as we might expect it.

 

Use 13 degrees for effective aerobraking.  Do not exceed 15 degrees 🙂

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On 12/26/2020 at 10:13 AM, Vekkinho said:

Yeah, the F-15C is a simplified flight model (as well as other FC3 flyables)

 

No it's not, and neither are any of the others.

 

On 12/26/2020 at 10:13 AM, Vekkinho said:

 

Wheelbraking is funny, I can't say if it works at all, keeping the W button pressed doesn't really slow You down in landig rolls

  Airplane is heavy and moving 200kts. It doesn't stop instantly. If you think it ''does nothing'' then try landing without using the brakes. We'll wait.

 

 

On 12/26/2020 at 10:13 AM, Vekkinho said:

and doesn't prevent rolling if you throttle up to ~90% RPM.

 Why would it? The engines can propel a 60,000lb+ aircraft to beyond Mach 2. Wheel brakes aren't going to stop it from moving anymore than your parking brake will keep a Toyota from being dragged around by a big rig.

 

On 12/26/2020 at 10:13 AM, Vekkinho said:

 

Differential braking (left and right wheelbrakes) cause major oscillations.

  At high speed, you should brake very gently... cause traveling 200kts on a high cg aircraft and applying 50% brakes will indeed roll you.

 

On 12/26/2020 at 10:13 AM, Vekkinho said:

Wheels tend to lock up so you skid around like crazy.

  Probably means you're going too fast and braking too hard. Also keep in mind the brake keybind is basically on/off, 0%/100%. That will lock your wheels and cause skidding.

 

 Other thing to keep in mind is the F-15's nose steering being tied to rudder pedals means it's very easy to add unintended NWS actions, which will definitely flip you.

 

  The Su-25s also are high CG, narrow wheelbase, with simplified braking/steering and are very prone to rolling or erratic taxiing, too.

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  • 2 months later...

TOTAL NOOB HERE - I just got in the F-15. Yes, on TO mine wants to drift horribly to the left at about 125kts or so and it's extremely difficult to correct. So I just rotate to get up as quickly as I can but risking a tail strike. Not to my liking but will practice it more and see what I can do about it. As for landing it's been difficult but I *think* I've got it after cracking her up some 12-15 times. I approach flaps down at about 160kts/2 degrees, cut power and hit air break right before touchdown. Once down keep nose up and then when it down pump breaks. If you are lined up pretty well just don't use any rudder at all. I made a video just last night doing this <<This is a full unedited screen capture so excuse the length. DCS VETS any suggestions other than the fact that I could had dropped tanks?>>

 

 

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On 12/30/2020 at 3:23 PM, Vekkinho said:

Perhaps I'm doing something wrong by keeping the AoA at 10° during landing rolls but my touch down to full stop time and distance seems equal as without aerobraking. Perhaps aerobraking ain't that effective as we might expect it.

 

I've witnessed F-15E doing a wheelie during landing roll, she was barely moving down the runway but pilot had a nose wheel up for 20 something seconds, playing with AoA as he liked it. Definitely much slower than 100TAS when DCS script drops F-15C nose. So that's why I still believe that fight model is heavy scripted / simple.

 

Check this vid at 3:43, it was closest I can find to what I saw live but camera footage here doesn't represent how slow they really roll. On the other hand here's the wet runway during airshow so pilots did no crazy stunts in this video.

 

 

 

 


Great video!

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As previously stated, there is no longer any "script" dropping your nose. All FC3 aircraft have been using the same full fidelity flight models as other DCS airframes for some years now. The MiG-29 was the last to receive the conversion, the F-15C the first. 👍 These days, it is only the avionics which have simplified.

 

 


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42 minutes ago, PanamaRed said:

This is a full unedited screen capture so excuse the length. DCS VETS any suggestions other than the fact that I could had dropped tanks?

 

You should have dropped tanks.   Actually, you shouldn't have taken tanks to begin with and you shouldn't be landing on that little runway with more than 6000lbs of gas.

 

Ok, totally obnoxious and subjective tank advice aside 😄

 

Twist stick or rudder?  Either way, check dead-zones and curves on rudder AND ailerons, but only after you do the immediate below step:

Bring the flight controls display up (ctrl-enter or ctrl-backspace, I forget which).   Can't tell squat without that display, meaning the video has little to no useful information for helping with this.

Stop switchingfrom outside to inside.  Stay inside, period.   Switching around doesn't help - in fact, do all of the above and do a video for TO only.  Yep, literally a short little TO video with all the necessary things turned on.  Make sure your gauges are visible and not to zoomed out that it's not possible to tell what's happening.

 

For technique:

* Be gentler on the rudder which may be rather difficult with a twist-stick.

* At high speeds you can put in a bit of aileron to control the nose instead of rudder.

* Your landing approach could use a bit of technique.   Peg 21 units AoA on a 3 deg glideslope.   Airbrake after the wheels touch the ground (it produces a downward force and is part of why your nose bounced - effectively too high sink rate overall).    Simply be stable on 21AoA on the 3 deg glideslope and then crack the power as required (depends on weight and other fun stuff) when you transition to the flare which you will peg at 23-24 units AoA (no more and no less) and hold that once the wheels touch the ground until aerobraking completes.   Less than 23, ineffective aerobraking, more than 25.5, tail strike.  This is the real basic landing technique so learn to execute this solidly, then you can do variations for heavy landings, engine out landings, no flap landings (Actually same procedure but longer rollout as no flaps means higher speed) etc.

 

You're going to transition into the flare right into wing-in-ground effect so if your AoA is too low you will float, too high AoA and you will stall especially if you bounce out of wing-in-ground effect or execute the flare too early.  The flare should have you floating down gently from an altitude of no more than 50'.


Edited by GGTharos

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Thanks GG - Well, just testing it out hence all the fuel. Using a new Logitech Extreme 3D Pro which I haven't yet totally assigned. Yeah...total noob at literally all of this. But, yeah "twist stick rudder". I will look into your advice for the rest.👍

As for the capture video I jumped inside and out. It is from a replayed saved track. The actual "in-world" flight I was in the cockpit all but part of the apron/ramp to runway off and on. Then after the landing when I came to a full stop I jumped out again to see what and if I had damaged anything. The jumping in and out was just a replay video capture. But I get what you're saying. I find staying in the cockpit much easier to fly so that's what I do.

Yes....the "technique", of which, I have none. I was just happy to get her down without damaging her or worse for once!🤣 But thanks for the advice. I will work on those. Will print your advice and have it on hand to refer to.👌

EDIT: I am new to OBS also but I will follow what you said and try and do a TO video ONLY also with what you had advised.

Thanks again, Bro.


Edited by PanamaRed
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@PanamaRed You're trying to unstick while being too slow. You're full of fuel with 3 bags of fuel. In that config 21 units of AoA would be achieved at 180-190kts. Bellow 180kts buffet onset, bellow 150kts probably stall. 

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