Flaring the NGX

[ebksb123 4]

Sorry for posting a new topic again, but suddenly I have a lot of questions

 

It's about how to flare the 737. When I put thrust to idle at about 20ft above the runway and then touch down, speedbrakes go up with a delay of a few seconds and reverse thrust also needs a few seconds until it works. This eats a massive piece of runway. I think that happens because the engines need a very long time until they are on idle, but I'm not sure about this, because this would mean, I had to put thrust on idle when I am above the threshold, at 50ft, to make the speedbrakes go up immediately, which seems not correct to me...

I've read about the engines going very slowly to idle, and that FSX only allows reverse thrust then, but I haven't found a solution

[usmc3073 3]

Make sure you level the aircraft over the threshold, and then drop throttle back, lastly gently flare it.

 

Guthrie

[KingGhidorah 209]

I think the most important thing is to NOT stare at the VVI or the artificial horizon. Focus your eyes at the end of the runway, and then re-orient the horizon visually about "an inch" or whatever roughly corresponds to approximately 2 degrees. You can get a feel for what 2 vertical degrees is visually, by noting the relationship of the horizon to the top of your glareshield when you pull the nose up using your artificial horizon during practice approaches. Soon it will become second nature and you will be able to get perfect touch downs without even having to look at your instruments. As previously stated, don't retard power until you hear the 20 foot callout.

[Ponk 51]

Your doing it correct assuming you are accurate with your speed, 20ft, cut throttles, flare, land, reverse thrust and auto brake. Spoilers deploy shortly after touchdown when there is weight on the landing gear, nothing to do with the throttles.

 

If you feel something is wrong, check your landing weight, somewhere around 5000kg or 11000lb for example. Flap 30 or maybe 40 for a shorter runway. Vref + 5 on approach, usually between 130 and 140kts. Auto brake 1 2 or 3 depending on conditions, taxi way locations etc.

 

Otherwise, cut throttles a little early, around 50ft, don't flare too much and float, greasers look nice but....eat runway, flare to no more than 3 or 4 deg usually prevents floating ( from my experience). A nice positive contact with the runway is better. Rough guide, hope it helps.

 

Iain

[G550flyer 1,015]

This what works for me consistantly. To get a good habbit pattern, use the HUD. Aim 1000ft down the runway. That should be easy to do with the HUD. I find the ngx a little floaty with the slow spool down so i cut the throttles at 50ft. Around the 20ft call out, raise the nose to 4 to 4.5 degrees. Once again the hud will be helpfull. When using the HUD, try not to place the aircraft nose reference above the 5 degree line. Shoot for just below it. After you get the habbit pattern and landing picture, transition from the HUD. This works for me everytime with consistant smooth landings. Just make sure you are stable on short final.

[ebksb123 4]

Thanks a lot for your answers! Probably I chose the title of the topic wrong, but it's about the spoiler and reverse thrust after touchdown. The part of the flare I'm not sure about is the point when to retard the throttles. One said now, not before 20 ft, and one said, around 50ft is possible, too. Maybe I'll upload a video showing the problem with the spoilers when I cut the throttles at 20ft.

I checked my landing speed again, but nothing should be wrong with it. Passengers 80-90%, fuel 10%, flaps 30°, Vref is about 140 knots and +5 knots = 145 knots.

I watched some real 737 landings and the speedbrakes usually go up immediately after touchdown, and I can only recreate this by cutting the throttles at AT LEAST 40ft.

[Arz2934 2]

he part of the flare I'm not sure about is the point when to retard the throttles. One said now, not before 20 ft, and one said, around 50ft is possible, too.

 

Make a few landings and experiment by retarding the throttles at different altitudes, and find something that works for you. I personally retard the throttles and flare at 30 feet, but you can make your own judgement.

[Rations 102]

Do the reverse thrust and speed brakes activate at approximately the same (delayed) time? If so, perhaps the speed brakes are not being armed correctly, and are merely deploying with the reverse thrust. Check visually in the virtual cockpit that the speed brakes have been moved to the armed position. (If you are setting a button to arm the speed brakes, sometimes it takes more than one push to complete the action.)

 

Also make sure that your controllers are set up properly. If using a throttle quadrant such as one by Saitek, make sure that the repeat rate for the reverse thrust detent is set to the maximum, so the simulator registers and complies with your demand for reverse thrust immediately after you select it.

 

As for proper flaring technique, please reference this excerpt from the official B737 FCTM:

 

"Initiate the flare when the main gear is approximately 20 feet above the runway by increasing pitch attitude approximately 2–3 degrees. . . .

 

After the flare is initiated, smoothly retard the thrust levers to idle, and make small pitch attitude adjustments to maintain the desired descent rate to the runway. Ideally, main gear touchdown should occur simultaneously with thrust levers reaching idle."

 

If you are indeed the YouTube user of the same name, I really enjoy your videos!

[Ponk 51]

I just flew from Greenland and landed at Glasgow, I cut the throttles at around 25ft, 137kts, N1 at touchdown was 34 and spoilers deploy pretty much immediately on touchdown.

 

Check your hardware as mentioned above, check your throttle idle properly, I also put a dead zone in my throttle at idle so the 1st 5mm mm of travel don´t do anything and can´t cause spikes which interput the reverse thrust.

 

Iain

[ebksb123 4]

Do the reverse thrust and speed brakes activate at approximately the same (delayed) time? If so, perhaps the speed brakes are not being armed correctly, and are merely deploying with the reverse thrust. Check visually in the virtual cockpit that the speed brakes have been moved to the armed position. (If you are setting a button to arm the speed brakes, sometimes it takes more than one push to complete the action.)

 

speedbrakes are armed correctly, I think. The lever goes back a bit and the green light saying "speedbrakes armed" is on.

 

If you are indeed the YouTube user of the same name, I really enjoy your videos!

 

Yes I am indeed the Youtube user, I'm glad you do!

 

I'm off for today, but in the late evening I should have some time to make some landings and try different retard-heights

[Rations 102]

speedbrakes are armed correctly, I think. The lever goes back a bit and the green light saying "speedbrakes armed" is on.

One last obvious thing to check for: even if you have armed the speed brakes correctly, make sure you are not using them afterwards and forgetting to re-arm them.

 

Otherwise, I suspect your issue relates to controller inaccuracies. Did you try troubleshooting the controllers as I recommended?

[kevinh 409]

I've read about the engines going very slowly to idle, and that FSX only allows reverse thrust then, but I haven't found a solution

I don't know where you read that but it is misinformation. FSX does not wait for the engine to go to idle before activating reverse thrust. All it needs is the thrust lever to be in the reverse position. The NGX is not slow to go to idle either.

 

Try controlling the throttle retard and reverse from the keyboard shortcuts F1 and F2. If the reversers respond quickly, as they should, then your problem is in your hardware setup.

[SierraHotel 982]

There was a post about this, regarding how the NGX likes to float above the runway and a fix for the same, I can't for the life of me think where I saw it......any one?

[Fabo 213]

There is a little trouble with how FS handles idle - that means, when you retard throttles to idle before TD, they only go to approach idle, and you need to push them to idle again as you land (ground idle). This can take about 2-4 seconds if you press F2. Only then will reverse unlock and open. That is at least my experience. For me, it helps to press F1 once or twice as I lower nose gear.

[kevinh 409]

There is a little trouble with how FS handles idle - that means, when you retard throttles to idle before TD, they only go to approach idle, and you need to push them to idle again as you land (ground idle). This can take about 2-4 seconds if you press F2. Only then will reverse unlock and open. That is at least my experience. For me, it helps to press F1 once or twice as I lower nose gear.

FSX doesn't know anything about approach idle or flight idle. These settings are in the NGX custom engine model. AFAIK these are modelled as a higher minimum N2 setting, just as in the aircraft. So you should be able to retard the lever to the idle stop in flight and get ground idle on touchdown (though there will be a few seconds delay, as in the real aircraft). However, it is the lever position which is important, not the engine rpm.

 

In my installation on touch down there is no need to reposition the levers to ground idle before selecting reverse. I use a MS Sidewinder with a simple throttle pot, but it should be possible to set up any throttle to behave correctly.