F-15 ILS approach profile.

[Holbeach]

I've been trying this ILS approach as demonstrated in RL.

 

140 kts, 19 units AoT, if it creeps to 20.5, add 1% power to go back to 19, then touchdown at 110 kts on a clean jet.

 

Aero brake stop by mid runway.

 

But I'm buggered if I can do it. :helpsmilie:

 

The testers have assured me it can be done.

 

So can somebody show me how?

 

Thanks.

Edited November 23, 2014 by Holbeach

[Ironhand]

Clean aircraft, <30% fuel. At least that works for me in a VFR landing. Not sure if ILS would change anything. Although I might have been at 145 kts. I don't really remember. I just remember being surprised at how well behaved the aircraft was during the sequence.

[Holbeach]

Clean aircraft, <30% fuel. At least that works for me in a VFR landing. Not sure if ILS would change anything. Although I might have been at 145 kts. I don't really remember. I just remember being surprised at how well behaved the aircraft was during the sequence.

 

Hello, thanks for that. I will cut down on the fuel and have another go.

 

the ILS slope is used because that is the original profile so I will stick to it.

 

 

Regards.

[GGTharos]

Approach AoA is 21 units. In game the ILS takes you go the middle of the runway which is a bit of a problem, so practice in Mineralne airport :-)

[Holbeach]

OK I cut the fuel to fumes, 10% and shot an approach to Mineralne at 140 kts down to 135. the 110 kts touch down was a bit of a struggle , but it's achievable as was 100 kts under control in level flight, but at 30 AoA It was touch and go. The RL jet had 2 tanks on, but they were empty so I shouldn't think they would make a difference.

It's difficult to tell if aero braking makes a difference, but it looks good.

I couldn't get the 115 ILS to work but the 295 was OK.

 

 

Regards

Edited November 23, 2014 by Holbeach

[Holbeach]

Is aero braking actually modeled in the game, or is it better just to drop the nose and brake normally.

[GGTharos]

Aero braking is modeled. You have to raise the nose and keep it between 13 and 15 degrees for it to be effective.

 

Brakes over-heating is not modeled, so there's no actual reason other than 'doing it right' to use aerobraking.

[Ironhand]

OK I cut the fuel to fumes, 10% and shot an approach to Mineralne at 140 kts down to 135. the 110 kts touch down was a bit of a struggle , but it's achievable as was 100 kts under control in level flight, but at 30 AoA It was touch and go. The RL jet had 2 tanks on, but they were empty so I shouldn't think they would make a difference.

It's difficult to tell if aero braking makes a difference, but it looks good.

I couldn't get the 115 ILS to work but the 295 was OK.

 

 

Regards

FWIW, here's my attempt: F-15 Circuit. Something for you to chuckle over. The -15's pit is not my home but I must say that, at 140 kts--once I got there--she felt stable. She also likes to slip through the air. I always have a hard time controlling her speed, whenever I'm in her pit. So touchdown was not at 110 kts but something higher.

 

 

Rich

[GGTharos]

The reason you're having trouble with the speed is that the overehad is poorly executed. Specifically:

 

You should be at 220kts on the reciprocal (this is basically so that everyone does things the same and doesn't mess up the spacing if you have 4 guys there). You shouldn't be slowing to 220kts, you should be at 220kts on the reciprocal.

 

Altitude should be a fairly steady 1500; AGL.

 

Configure when passing the 500' markers (so slightly before you pass RWY threshold).

 

Let speed decay to 180.

 

 

When you see the RWY threshold 45deg behind you (too early, you'll have to abort, too late, bomber pattern):

Bank the plane 45deg and let the nose fall to 10deg (W on -10) before you start pulling. Do not exceed 30AoA in the pull, if you do, just abort.

 

Roll out on RWY heading ON GLIDESLOPE (you rolled out too high, that's why you had trouble controlling speed) and AoA of 21.

 

Maintain 21 until ground-rush, then pull power and flare. (This changes if you're heavy ... flare, then pull power).

 

The touch-down speed is 'you should end up touching down at...' not 'aim to touch down at ... ' - watching speed doesn't help your technique. Use a good approach and flare technique and the plane will do the work for you.

 

Actual touch-down speed can vary quite a bit depending on the actual touch-down desired (ie. very soft when alone, to firm in formation landings).

Edited November 23, 2014 by GGTharos

[Ironhand]

Thanks! Something to work on as time allows. I knew I wasn't doing it by the number but, then again, I didn't know what the numbers were. :) I like the fact that, with an AFM, you have to do it right or it doesn't work.

 

The reason you're having trouble with the speed is that the overehad is poorly executed. Specifically:

 

You should be at 220kts on the reciprocal (this is basically so that everyone does things the same and doesn't mess up the spacing if you have 4 guys there). You shouldn't be slowing to 220kts, you should be at 200kts.

 

Altitude should be a fairly steady 1500; AGL.

 

Configure when passing the 500' markers (so slightly before you pass RWY threshold).

 

Let speed decay to 180.

 

 

When you see the RWY threshold 45deg behind you (too early, you'll have to abort, too late, bomber pattern):

Bank the plane 45deg and let the nose fall to 10deg (W on -10) before you start pulling. Do not exceed 30AoA in the pull, if you do, just abort.

 

Roll out on RWY heading ON GLIDESLOPE (you rolled out too high, that's why you had trouble controlling speed) and AoA of 21.

 

Maintain 21 until ground-rush, then pull power and flare. (This changes if you're heavy ... flare, then pull power).

 

The touch-down speed is 'you should end up touching down at...' not 'aim to touch down at ... ' - watching speed doesn't help your technique. Use a good approach and flare technique and the plane will do the work for you.

 

Actual touch-down speed can vary quite a bit depending on the actual touch-down desired (ie. very soft when alone, to firm in formation landings).

[GGTharos]

No problem - usually the fine points of technique aren't anywhere to be found when you're looking around on the net. Personally I barely know anything about flying, but I know an instructor or two in RL :)

 

Also, this is just one technique - there are speedier ones as well, but the theme tends to be the same: Execute the prescribed procedure. :)

[Holbeach]

Only the 1st part of this vid is relevant, but the target numbers must be the aim of the exercise (TF 15A test flight, 140 kt app on the ILS, 19 units AoT and 110 kt touch down), how you achieve it is up to you.

Ground effect might not be modeled so the TD might not be achievable.

 

 

 

[GGTharos]

You probably put the under-carriage right through the wings, it's just not modeled yet.

 

The correct numbers are 21uAoA, and ignore the speed, which varies by aircraft gross weight. In addition, you're badly off glide-slope, which results in the rapid descent. Very poorly executed landing, and not on any sort of 'target numbers' that are used with the real aircraft.

 

Only the 1st part of this vid is relevant, but the target numbers must be the aim of the exercise (TF 15A test flight, 140 kt app on the ILS, 19 units AoT and 110 kt touch down), how you achieve it is up to you.

Ground effect might not be modeled so the TD might not be achievable.

[Holbeach]

You probably put the under-carriage right through the wings, it's just not modeled yet.

 

The correct numbers are 21uAoA, and ignore the speed, which varies by aircraft gross weight. In addition, you're badly off glide-slope, which results in the rapid descent. Very poorly executed landing, and not on any sort of 'target numbers' that are used with the real aircraft.

 

You don't seem to understand the rules here, so I will explain them again.

 

You don't use parameters that you know will work with the game plane.

 

You use the numbers that have been demonstrated in a REAL F-15, repeat REAL F-15 (140kt, 19AoA, 110kts) and then try to fly them with the game plane as I did, to see how the FM compares. This will probably give a hard touchdown.

 

The weight is at a minimum, (clean with 10% fuel), as previously stated to give it the best chance.

 

The glide slope wasn't working and not used, as explained in text.

 

Try to keep up and don't be so bloody rude just because you can't grasp it.

[GGTharos]

You use the numbers that have been demonstrated in a REAL F-15, repeat REAL F-15 (140kt, 19AoA, 110kts) and then try to fly them with the game plane as I did, to see how the FM compares. This will probably give a hard touchdown.

 

Yes, that's right. I use the same numbers that are described in the -1 TO that every real F-15 pilot uses. For the real plane. And the real, I repeat REAL landing technique is to fly the AoA and glidepath for the desired type of approach, not the speed.

 

The glide slope wasn't working and not used, as explained in text.

All approaches are on a glide-slope, you don't need ILS for it.

 

Try to keep up and don't be so bloody rude just because you can't grasp it.

I explained to you what what was wrong with your approach. If your approach is not flown with the same technique as the RL approach, your test is not valid. Edited November 24, 2014 by GGTharos

[Ironhand]

...use the numbers that have been demonstrated in a REAL F-15, repeat REAL F-15 (140kt, 19AoA, 110kts)...

 

The glide slope wasn't working and not used, as explained in text...

Is there a in-cockpit video or source you can point me to? I'm curious about the glide slope used to achieve those numbers among other things. Do you have any idea?

 

 

Rich

[Holbeach]

Is there a in-cockpit video or source you can point me to? I'm curious about the glide slope used to achieve those numbers among other things. Do you have any idea?

 

 

Rich

 

The source is Capt. Don Carson USAF 1st flight in the TF 15A.

 

https://www.scribd.com/doc/61893068/SSP-In-Action-024-McDonnel-Douglas-F-15-Eagle

 

If you can shoot this down with a structured argument, I'll be quite happy to accept it.

 

.

[blkspade]

The source is Capt. Don Carson USAF 1st flight in the TF 15A.

 

https://www.scribd.com/doc/61893068/SSP-In-Action-024-McDonnel-Douglas-F-15-Eagle

 

If you can shoot this down with a structured argument, I'll be quite happy to accept it.

 

.

 

Oh well that probably as simple as the TF15A not being the exact same plane as the F-15C. Base weight is different as are the engines.

[GGTharos]

P17 paragraph 5, first sentence: I intercepted the glideslope. (As I said before: You didn`t. And no, you don`t need the ILS for it. Approach is 2.5 to 3 deg angle, ILS will give you the same - you did 5 or more.)

 

And yes, you`ll fly a stable approach at 19AoA on the glideslope, but that`s no the technique used on the production eagles. 19 units leads to floating. Buffet at 20.5 AoA makes me suspect this wasn`t a production aircraft.

 

The wingtips were tapered back later on (With saw and plywood! :) ) specifically to get rid of such buffet, as well as even worse buffet at some other flight regimes.

[Holbeach]

Oh well that probably as simple as the TF15A not being the exact same plane as the F-15C. Base weight is different as are the engines.

 

At last a sensible answer.

 

The aircraft was lighter and coupled with the real world ground effect was able to make a smooth landing at 110 knots.

[GGTharos]

Engines won`t have an effect on this.

The base weight is only some 1000lbs apart, so unless he was landing with an unacceptably low fuel level, you can fly the same parameters.

 

 

 

Oh well that probably as simple as the TF15A not being the exact same plane as the F-15C. Base weight is different as are the engines.

[Ironhand]

The source is Capt. Don Carson USAF 1st flight in the TF 15A.

 

https://www.scribd.com/doc/61893068/SSP-In-Action-024-McDonnel-Douglas-F-15-Eagle

 

If you can shoot this down with a structured argument, I'll be quite happy to accept it.

 

.

:) Neither trying to prove nor disprove. I was curious about your source and would like to understand the difference between it and what we "fly". I notice that you're referencing the TF-15A model, while we're in the C.

 

It's hard to tell for certain but the only source I've come up with for the (dry) weight of the two seater test platform ( Avialogs TF-15A ) indicates that it's 26,289 lbs. I'm not home so I can't look to see what the weight of our sim model is but online sources place it's (dry) weight variously from 28,100 to 28,600 lbs. Wonder if close to 2000 lbs difference in weight might account for a large part of the discrepancy.

 

That would be a weight difference of roughly 7%. Don't know if it translates directly--it'd take more brain power than I want to devote to it ATM--but add 7% to 140 knots and you get 149.8.

 

 

EDIT: Opps. Guess I should have refreshed the page before posting. Late to the party.

 

 

Rich

Edited November 24, 2014 by Ironhand

[GGTharos]

The -1 and lists the F-15B (Essentially TF-15A renamed) at 28500lbs with pilot, oil, and unusable fuel.

 

The F-15C is listed at 29000lbs under the same circumstances.

 

The approach chart indicates a 34000lbs aircraft for a 140kts approach, but this chart is also for the 21 units, not 19.

[Ironhand]

The -1 and lists the F-15B (Essentially TF-15A renamed) at 28500lbs with pilot, oil, and unusable fuel.

 

The F-15C is listed at 29000lbs under the same circumstances.

 

The approach chart indicates a 34000lbs aircraft for a 140kts approach, but this chart is also for the 21 units, not 19.

So, a lot less difference than I had thought. For a 19 units approach, you'd need to be going faster than 140 knots, if the weight was the approach chart weight.

[GGTharos]

I can do it with 950lbs of fuel on approach, but just barely. The speed/AoA reports may also not be the most accurate.

 

You'll be able to hold 19AoA at about 141-142kts. I touched down with 115kts, but I could have rounded out the flare a lot more than I did as well, and probably reduced that by 110kts - but the sink rate was starting to pick up.