Landing... AOA, Trim vs Throttle

[euthyphro]

Some tutorials say when landing to control your AOA with throttle... Others say to control AOA with trim.... Any clarification on this?

 

 

 

 

Thanks

[Brun]

The ones which say AOA is controlled by throttle are simply wrong.

[Lex Talionis]

Have a tutorial specifically on this.

 

EDIT: had to read this a few times. AOA and throttle, no idea how this could have become mixed up. I understand your frustration. Maybe "trim for airspeed" has some how become conflated to mean trim with throttle. (Shrug)

 

Easy answer..... ya trim for an airspeed.

 

-hope this helps :)

Edited April 7, 2019 by Lex Talionis

[AG-51_Razor]

In the Hornet, when in the landing configuration (landing gear and flaps down), the AFCS will maintain whatever AOA you set with trim and the throttle will control vertical speed. By this I mean, once you are in the landing configuration the throttle will be used to control your rate of descent, which will keep you on the glide path. Avoid pushing or pulling on the stick because the AFCS will fight you with trim!

[macedk]

The ones which say AOA is controlled by throttle are simply wrong.

 

wrong on all :)

 

What AOA you want is done by trim . Keep the set AOA can be controlled with throttle only.

Edited April 11, 2019 by macedk

[Jagr]

AOA is maintained by the trim.. trim the left hash of the AOA marker to the middle mark on the AOA cue when the gear is down. The AOA cue itself then needs to be constantly adjusted with throttle to determine where your plane is actually going. So the key I found was to get level and trimmed for a low speed with gear and flaps down.. then start BOTH lowering power (so the AOA marker will start to sink (and the plane starts to descend) and then also adjust on speed AOA to remain in the middle of the AOA cue. So on a trap there are several things happening at once that all need to be in synch. You need the flight path marker on the carrier where the wires are AND you need the AOA trimmed so that you have about 8' of AOA AND your speed and sink rate will let you end up on the deck with survivable forces on the jet:) I try for about 3-4' of glide slope and it seems to work well. DO NOT give pitch inputs once you are trimmed.. use lateral stick for turning and then throttle to wither raise or lower the flight path marker while trimming to keep the AOA centered up.. It actually sound more complicated than it is.

[Jagr]

The key is to be trimmed out and at the proper speed and altitude to start the downwind. Is you are WAY too high or WAY too fast you will have to have major adjustments trying to force the landing and likely auger it. If you are doing it right the throttle will get a serious workout on the final as you try to maintain flight path marker in the middle of the desk as you close on it There is a throttle lag so you need to anticipate and give corrections without letting it rise or fall to much.. If you start at the right right and you get the slight path marker on the deck middle and are on AOA then your glide slope will be what you want

[Cyborg71]

Lex is the expert here. His tutorial is golden.

 

Many moons ago I did enquire as to why the stick inputs were taboo, when I'd seen hornet vids with pilots using stick within the last phases of approach. This was explained as just balancing as you pass through burble and wind/turbulence. changes

 

Get the aircraft quickly & efficiently trimmed on speed (fpm centred in the e bracket and bright orange circle donut on the aoa). No need to reference actual airspeed.

 

I heard/read somewhere advice for managing the throttle movement as

One inch on, half an inch off. Or one inch off half inch on. Pause for effect....repeat.

 

These inputs keep things where they need to be.

Edited April 9, 2019 by BrianSansum

[_mu110_]

Is the burble simulated in DCS?

[LURKINGBADGER]

thats unknown to this day, havent seen it being deneied nor confirmed by ED

[Akula]

Real men hand fly it in. NO TRIM! Now if you'll excuse me, I'm off to shoot a small animal chop down a tree and have a beer.

[euthyphro]

So if I understand correctly, trim controls AOA (which is automatically maintained once set or do we have to constantly adjust with trim?), and throttle controls rate of decent or where the plan will essentially touch down? Do I understand this correctly?

 

 

BTW, with Mig 21 and A10 I have always used throttle to control landing AOA... Have I been doing that wrong too??? Should I use trim to control AOA for those planes as well?

Edited April 11, 2019 by euthyphro

[DocSigma]

So if I understand correctly, trim controls AOA which is automatically maintained once set, and throttle controls rate of decent or where the plan will essentially touch down? Did I understand this correctly?

 

Pretty much. The fpm will determine where the plane will touch down. However, you want to be at the proper AOA when the plane touches down so being on speed AOA at touchdown ensures a smooth landing. Once you are on speed - fpm lined up with the center of e-bracket - all you need is throttle to control your rate of descent or climb. She'll stay on speed. If she deviates from on speed, just use trim, not to much, to get her back on speed. From there, its only stick deflections left or right. Use throttle to control your descent. The Hornets engines aren't as responsive as say the tomcats so you kinda have to anticipate a bit with the throttle. Just keep the throttle always moving. If you lay off the throttle thinking she'll hold the donut on the indexer, she'll drop pretty hard forcing you to go pretty heavy on the throttle. Just maintain a constant descent rate by always working the throttle.

 

Best way to practice getting on speed pretty quickly is at altitude. Get up to 15 or so thousand feet, fly level and cut speed to 250knots, then drop flaps and gear. Get the plane on speed, and just manage descent and climb rate with the throttle getting used to how the plane responds to your inputs. No runways, just climbing and descending.

[EAF602 Red]

Pressing the ATC button once you have the correct AoA will keep it where it is set, then just concentrate on throttle, remember the engage ATC early sometimes it will take a sec to engage

 

Red

[macedk]

Pressing the ATC button once you have the correct AoA will keep it where it is set, then just concentrate on throttle, remember the engage ATC early sometimes it will take a sec to engage

 

Red

 

Ehh you know that ATC is auto throttle control right ?

[macedk]

At this point Original poster is more confused, no trim flying, atc etc.

 

Always check your choices as the internet will say all kinds of things and many are not right :)

 

Lex is a former F-18 pilot and has a video on this. Lex has a discord aswel. To OP, Go there for correct information :)

[Deano87]

Pressing the ATC button once you have the correct AoA will keep it where it is set, then just concentrate on throttle, remember the engage ATC early sometimes it will take a sec to engage

 

Red

 

What? Lol

[kengou]

Pressing the ATC button once you have the correct AoA will keep it where it is set, then just concentrate on throttle, remember the engage ATC early sometimes it will take a sec to engage

 

Red

Not true. The auto-throttle (ATC) is not functional yet for landing configuration. Once gear is down right now the plane's flight control system automatically changes trim laws: the plane stays automatically in trim at its current AOA. Trim changes the set AOA. If auto-throttle becomes functional in the future it will maintain on-speed throttle for you if you change the pitch on the stick, allowing you to change the glideslope using pitch instead of throttle.

[EAF602 Red]

ATC in Approach mode

 

 

https://forums.eagle.ru/showthread.php?t=212370

 

 

Red

[Deano87]

ATC in Approach mode

 

 

https://forums.eagle.ru/showthread.php?t=212370

 

 

Red

 

ATC currently doesn't work properly in approach mode. If you suggest using it you don't understand how it works. You said to engage ATC and then concentrate on the throttle. The whole point of ATC is that it take over throttle control to maintain the trimmed AOA, so once you engage it you should leave the throttle alone.

 

The thread you linked to says not to use it.

[bonesvf103]

 

I heard/read somewhere advice for managing the throttle movement as

One inch on, half an inch off. Or one inch off half inch on. Pause for effect....repeat.

 

 

Close...really for the throttle it is "When low, a little on a little off, then half back on" and "when high, a little off, a little on, then half back off."

 

 

Now "a little" is of course subjective, but will depend on the result that you see from your action. The idea is that say you are getting low. Increasing the power decreases your rate of descent and thus you will rise up to meet the glideslope. However, leave that power on and you will climb past that glideslope, so you have to take the power off to compensate and slow/arrest the climb. However, pulling the power, you are back to your original dilemmna of possibly going below glideslope, so you add just a little more power to halt that descent (not so much as to cause another climb) and thus maintain your position on the slope. Observe the situation now, rinse, and repeat. Naval aviators call it a three-part power correction.

 

 

 

Bottom line is that the throttle controls your rate of descent while the pitch (stick and trim) controls the airspeed and AOA.

 

 

 

v6,

boNes

[euthyphro]

Thanks for the information and the replies. Not to muddy the waters even more but what is the E bracket representing? Is it AOA, Pitch, descent rate, or a combination of these???

[Jak525]

Thanks for the information and the replies. Not to muddy the waters even more but what is the E bracket representing? Is it AOA, Pitch, descent rate, or a combination of these???

Angle of attack, purely. When the velocity vector is in line with the middle line of the E shape, your AOA is 8.1°. If it's above it, your AOA is more than 8.1. If the velocity vector is below it, your AOA is less than 8.1.

[CaptJackG]

First understand the FCS.

 

With the flaps AUTO the FCS flies a 1G aircraft. You do not trim the ac when flaps are in AUTO, just point the nose where you want to go and the FCS will take care of the pitch trim.

 

All that changes when you go to 1/2 or FULL flaps. The FCS now flies AOA. Specifically it sets the AOA to 4.0. You can get airborne and slow to 230, LDG down and maintain 230.

 

You'll see the E-bracket appear when the LDG is down. Your E-bracket represents your AOA indexer just on the left side of your HUD. When your VV (Velocity Vector) touched the bottom of the E-bracket you'll see the donut and bottom chevron, as you approach the middle of the E-b you'll get the donut, and if you continue towards the top of the E-b you'll see the donut and top chevron.

 

Now back to our flight (stable at 230 LDG down), you'll notice your AOA number displayed on the left side of your HUD, start to slow while holding altitude until your VV is in the center of the E-b. You'll see your HUD AOA numbers disappear from your HUD when your VV touches the E-b. If you have your FCS page on a DDI you can see your actual AOA number and the bottom of the FCS page on the left and right at the bottom showing the actual readout from the 2 AOA sensors. Stabilize your VV in the middle of the E-b, you can see the AOA on the bottom of the FCS page showing 8.1 AOA. Your ac FCS is still flying a !G environment.

 

Your 8.1 is the optimum AOA for trapping, best app speed and hook attitude.

 

Now we will select flaps !/2.

 

Don't trim the ac!!!!!!!!!

 

Your FCS is now flying AOA, not the 1G. We now want to use the throttles to control our altitude. Get your ac stable, on altitude without retrimming. When you get stable you will see your AOA sitting at 4.0. Doesn't matter whether you go to 1/2 or FULL flap the initial FCS setting is 4.0. You'll find yourself constantly making small power adjustment to hold your altitude. You can now start to slow your ac by reducing power and bumping your trim up until you have the VV in the middle of the E-b. Stabilize the VV in the middle of the E-b. Again when your VV touches the E-b you'll lose your AOA readout on your HUD. You can look at the FCS page on the bottom and see 8.1 when the VV wing touched the middle of the E-b.

 

You can now practice flying the proper AOA using the throttles to control your altitude and app path, let the FCS control your AOA.

 

Hope this helps and answers some of your questions. This is all part of the training we do in VCVW 11.

 

"Homer" DCAG VCVW 11

[BuzzU]

I'm surprised how many got it wrong in the beginning of this thread. No need for long explanations.

 

The throttle never controls the AOA. Trim does that.

 

Throttle controls the pitch.