Glideslope on HUD

[Baz000]

Anyone have a picture of where the flight path marker needs to be on the bud to be on a -3 degree glideslope for landing and in relation to the landing runway

 

The pitch ladder clearly defines the horizon, 0 degrees and -5 degrees... And using logic one can extrapolate that in the middle of 0 and -5 degrees is -2.5 degrees.

 

But where exactly would -3 degrees be for proper landing glideslope?

[fitness88]

I keep the AoA at around 21-23 and keep my decent at around 700 fpm on final, then flare just before TD to 200-300 fpm.

[razo+r]

you can also just follow the ILS glideslope...

[fitness88]

you can also just follow the ILS glideslope...

 

 

 

I should but never got comfortable with it...do all airfields have ILS?

[26-J39]

I keep the AoA at around 21-23 and keep my decent at around 700 fpm on final, then flare just before TD to 200-300 fpm.

 

You should hold 21units till touchdown, using throttle to reduce decent rate.

[razo+r]

I should but never got comfortable with it...do all airfields have ILS?

 

A lot of the western airports have it

[GGTharos]

Turn off the HuD and do it visually instead. For reference, the correct glideslope is ~300'/nm of distance from threshold.

 

Anyone have a picture of where the flight path marker needs to be on the bud to be on a -3 degree glideslope for landing and in relation to the landing runway

 

The pitch ladder clearly defines the horizon, 0 degrees and -5 degrees... And using logic one can extrapolate that in the middle of 0 and -5 degrees is -2.5 degrees.

 

But where exactly would -3 degrees be for proper landing glideslope?

[VampireNZ]

I should but never got comfortable with it...do all airfields have ILS?

 

No all airfields do not have ILS

 

Turn off the HuD and do it visually instead. For reference, the correct glideslope is ~300'/nm of distance from threshold.

 

Interesting advice, but that sort of defeats the purpose of the OP's actual question.

 

 

Baz000 - don't get to hung up on the perfect glideslope, if you are not using the ILS then you are performing a visual approach which is defined as a 'non-precision approach'...hence exact 'precision' is not a requirement.

Yes you can just extrapolate the 3 deg by holding the FPM just below halfway to the -5 deg line as you say and that will be plenty accurate enough - but if you really want to get a good visual indication of how it should look just perform some approaches at an airfield using the PAPI (precision approach path indicator) lights and compare.

[fitness88]

A lot of the western airports have it

 

 

Flying DCS Caucasus, I remember now the charts show which runways have ILS. About how far out on final will my needles become active?

[Baz000]

added a DCS track of trying to land the F-15C as heavy as I could get it without causing damage... 4 120's and 4 AIM 7's and 3 external tanks... Worst case scenario for landing a really heavy bird. I was looking for maximum landing weights and couldn't find any. So i'm guessing with the correct technique you can land it heavy.

 

Boy that mantra of 21 units of AOA is magic, automatically adjusts for your payload causing higher approach speeds.

 

lemme know what you think

F-15lndg.trk

[GGTharos]

The flare is different for a very heavy landing - leave power in until touch-down and you can bring it in on a 2deg glide slope, too. Make sure you have a long enough runway, too!

[Baz000]

What I did was keep 21 units of AOA and then as the runway filled the width of the hud brackets, I started my flare by increasing pitch to where the flight path marker was on the other end of the runway and then I reduced throttle to idle. Soon as the main wheels touch the ground I extend the airbrake and hold the nose 10 degrees pitch until nose wheel lowers (usually takes full aft stick) then I hit the wheel brakes until I'm stopped.

 

Btw I noticed that the wheel brakes are making me yaw around when I'm trying to stop... used my rudder pedals toe brakes and tried also pressing the W key on the keyboard... The plane wants to wobble in yaw left and right. Any ideas what could be causing this? I don't think it's my controls setup

 

Maybe the breaks are skidding or slipping

[tflash]

 

Btw I noticed that the wheel brakes are making me yaw around when I'm trying to stop... used my rudder pedals toe brakes and tried also pressing the W key on the keyboard... The plane wants to wobble in yaw left and right. Any ideas what could be causing this? I don't think it's my controls setup

 

Maybe the breaks are skidding or slipping

 

 

I have exactly the same problem, landing goes smooth, shock free on touchdown doing a flare like you do, but then suddenly the airplane starts to veer off in all directions and even the lightest correction makes it bend over. I end up with my both tail wheels bended a little inwards.

 

Does this mean my landing speed (somewhat above 150 knots is still to high?) I think my vertical descend rate is OK. I land with full A2A combat load and about 50% fuel.

[fitness88]

I found for braking with the F-15, using nose wheel steering disabled, 1 second on 1 second off the brakes...repeat till 50 knots or less keeps you pretty straight, then enable nose wheel steering..

Edited September 4, 2017 by fitness88

[GGTharos]

Why brakes? Aerobrake at 13 deg pitch (less than 13 is not effective) until less than 90kts, then just roll out.

If you landed on a short runway, consider using AC different airfield :)

[Baz000]

Are you not supposed to use wheel brakes when below 90 knots and nose wheel planted on the ground?

 

No such thing as disable nose wheel steering on the F-15, it just makes the nose wheel free swiveling.

[fitness88]

Are you not supposed to use wheel brakes when below 90 knots and nose wheel planted on the ground?

 

No such thing as disable nose wheel steering on the F-15, it just makes the nose wheel free swiveling.

 

 

 

Allows only rudder steering with no NW involvement, I find the F-15 to be more controllable above 50. There are several threads on this, correct or not it works for me

[Baz000]

any tips on landing the F-15 with no external stores and only 30% of fuel? I keep landing too hard and busting my main gear struts...

 

Funny that I can land extremely heavy okay, but when light I break the gears...

[Ironhand]

any tips on landing the F-15 with no external stores and only 30% of fuel? I keep landing too hard and busting my main gear struts...

 

Funny that I can land extremely heavy okay, but when light I break the gears...

I'll take a shot at this. The Eagle isn't my usual ride but, with any aircraft, the weight extremes tend to be more problematic. Assuming you're still holding the 21 units of AoA down to the runway, the problem now is that you're flaring too early (as in too high) by using your usual sight picture.

 

With the lighter weight, you'll float longer. As you pitch your nose up to settle, it takes longer to start heading down. That means that your speed has time to decay a bit more while you're still high and you then drop like a stone as you stop flying. Try holding off the flare until you're a bit lower and you should be OK.

 

Edit: Just came back to add that I recorded a quick track this morning before work. I still bounced the landing, though. If you promise not to laugh and feel a need to view it, Baz000, let me know and I'll post it. I'd forgotten how odd it feels to fly a self-trimming aircraft. You only have to deal with the AoA controller (stick) and throttle. No trim button to worry about, too.

Edited September 5, 2017 by Ironhand

[GGTharos]

Unless you're on a short runway (in which case you might not want to aerobrake at all), there's just no reason to use the brakes. Roll to the end of the runway instead.

 

Are you not supposed to use wheel brakes when below 90 knots and nose wheel planted on the ground?

 

No such thing as disable nose wheel steering on the F-15, it just makes the nose wheel free swiveling.

[Ironhand]

Just ran across this rather neat video of an F-15 landing at Portland Airport (PDX):

 

 

 

Portland's runway is 2995 meters. So about 3/4 the length of Mineralnoye Vody but longer than a number of the Caucasus airbases.

Edited September 5, 2017 by Ironhand

[tflash]

I'll take a shot at this. The Eagle isn't my usual ride but, with any aircraft, the weight extremes tend to be more problematic. Assuming you're still holding the 21 units of AoA down to the runway, the problem now is that you're flaring too early (as in too high) by using your usual sight picture.

 

With the lighter weight, you'll float longer. As you pitch your nose up to settle, it takes longer to start heading down. That means that your speed has time to decay a bit more while you're still high and you then drop like a stone as you stop flying. Try holding off the flare until you're a bit lower and you should be OK.

 

Edit: Just came back to add that I recorded a quick track this morning before work. I still bounced the landing, though. If you promise not to laugh and feel a need to view it, Baz000, let me know and I'll post it. I'd forgotten how odd it feels to fly a self-trimming aircraft. You only have to deal with the AoA controller (stick) and throttle. No trim button to worry about, too.

 

I'll try that! Indeed I do flare and then things seems to go wrong.

 

PS GGTHaros I indeed want to land on fairly short runways in Caucasus Map.

[GGTharos]

For shortest run landings: approach at 23uAoA (yes, you will have to be VERY accurate with your throttle and pitch) and about 2deg AoA.

 

Upon touch down, nose gear on ground and apply max braking.

[Ironhand]

For shortest run landings: approach at 23uAoA (yes, you will have to be VERY accurate with your throttle and pitch) and about 2deg AoA.

 

Upon touch down, nose gear on ground and apply max braking.

That last should be interesting. Max braking would have me swerving all over the runway...if I could even stay on it long enough to come to a braked stop--as opposed to a broken and shattered stop.

 

Ummm..2 deg AoA???, 2° glide slope?

 

 

EDIT:

 

Tflash, no less an authority than Wikipedia says that F-15 need 2,286 m (7,500 ft) to land. Someone in these fora once stated 2134 m (7,000 ft). So Nalchik's runway would be the shortest, if true. Someplace like Novorossiysk or Gelendzhik at 1,800 m would be too short. Supposedly the F-15 has chintzy wheel brakes... :)

Edited September 5, 2017 by Ironhand

[GGTharos]

Yes, I meant 2 deg glideslope :)

 

Also note that TOLD calculations include safety margins etc. So 7000' is something you need, and that's already a short runway and you should be landing light. A 12000' runway will accommodate any configuration, I think.

Edited September 5, 2017 by GGTharos