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The big E bracket


directorguy7

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Have to admit, with all the hours of Sim flight, never flown a plane with Onspeed indicator like this. I have an idea of what its doing but I think the tutorials blow through what its actually doing in relation to your physical jet.

 

For example, the Flight Path or velocity vector essentially is saying regardless of your horizon indicator or direction you are facing, this is (as best as a HUD can tell you) essentially what your jet is actually physically doing.

 

Or how the HUD floats to indicate slide

 

Is the AOA bracket doing something similar, or is it purely technical info versus some sort of literal info the plane is doing? I've made a few carrier landings but totally VFR. Would be nice to know the stall speed with no weapons loaded as well.

 

Interesting jet, and a lot of tech in this thing, it basically flies it self (seems to self trim almost.) Very cool Fly by wire system where you ask the plane to do something and its computer decides if it wants to.

 

Also any way to change G limit?

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The E bracket is basically telling you not what the jet is doing, but what it wants you to do. The Hornet needs specific AoA in order to land safely, and the E bracket gives feedback to the pilot to setting up the proper AoA.

 

It's entirely possible to do it without the bracket and use only the indexer donut like in other aircraft, but the E bracket is by far more accurate. The FCS page also provides your AoA in numerical format along the bottom of the page which can be helpful when setting up trim.

 

Stall speed will differ depending on fuel load, but if performing a carrier recovery, you should be under a specific weight restriction (generally under 33k to 31k total lbs.) as noted in the NATOPS. So the stall speed should be roughly the same as long as you're following weight restrictions (A/C total weight can be seen on the CHKLST page). Stall speed at or below the weight restriction is somewhere around 120 knots, generally while under normal flight you'll want to keep IAS above 180 knots.

 

G-limit can't be changed, since it's dynamically set by the FCS. You can override the G-limit and increase it by 33% by holding the paddle switch, but only while held.

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Pretty much all military circuit flying is done on Alpha (AoA) rather then airspeed. This sounds odd for somebody coming from civilian flying but there is logic to it. Under 1G conditions the aircraft will always stall at the same angle of attack, regardless of weight. Now, obviously the speed you're flying at at when the wing reaches its critical (stall) AoA will be different, slower for lightly loaded aircraft and faster for heavier loaded aircraft.

 

With military aircraft the landing weight can vary drastically from a heavy jet bringing back unused ordinance to a lightweight clean jet having just finished an air display. If you fly AoA then speed will take care of itself, as long as you're below max landing weight and you fly the right AoA on approach you know you are at the right speed for your given aircraft weight, if you were too slow your AoA would be too high (close to stall) if you were too fast your AoA would be too low.

 

As far as the E bracket itself, its just showing you the ideal AoA window for landing, If you get the velocity vector within that E bracket then you know you're at the correct AoA for the approach configuration. The Hornet does take it a step further then most jets by having the FCS try and hold a certain AoA which you program in using up trim after having dropped gear and flaps. After you're configured its just a case of flying the Velocity vector vertically using power and placing it on the end of the runway on a 3degree glide slope. Then just fly it into the runway without a flair. Pretty easy really.

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@USMC_Trev correct, but he was specifically talking about stall speed with no weapons loaded, therefore payload wasn't relevant in the context of carrier landings.

REAPER 51 | Tholozor
VFA-136 (c.2007): https://www.digitalcombatsimulator.com/en/files/3305981/
Arleigh Burke Destroyer Pack (2020): https://www.digitalcombatsimulator.com/en/files/3313752/

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To put into context ...

 

 

 

The E bracket is simply a HUD pictorial representation of the AOA gauge.

 

The indexers are simply another independent pictorial indication of the AOA gauge.

 

The AOA gauge is simply an arbitrary numbering system to represent a relative AOA of the wing. (i.e. 12 units AOA on the gauge is NOT necessarily 12 degrees of measured angle of the actual cord line of the wing to the relative wind)

 

The elevator trim of any aircraft controls the angle the cord line of the primary lifting plane (the wing in this case) will hit the relative wind at. This will yield a lift vector of X that will happen at an airspeed Y regardless of attitude if the aircraft is allowed to seek this airspeed once trimmed ("hands off trimmed up" among other phrases). Trim can be synonymous with "equilibrium" in this context. One very common misconception is that you trim for an attitude, this is incorrect.

 

What does this mean to you as the front seat stick actuating meat puppet?

A pilot trims for an airspeed (elevator trim), and the aircraft will seek it greatly reducing the work load of the pilot. For which the pilot modulates the power to achieve the attitude they want. (climb, descent, lvl, etc)

 

In the context of ball flying, we do not care the airspeed, we care for the more rudimentary AOA (and for a few other reasons outside of this scope) such that the hook remains at the correct angle to hit the wire.

 

This is the E brackets function: trim so the VV is in the center of the E bracket. Once trimmed, if the aircraft is flown correctly, the VV and E bracket will move together. Not only will this keep the proper angle for the aircraft, their fore the hook, but the aircraft will actively seek that AOA and try to remain "on speed" for you. This only works with the primes of, you have the aircraft "no kidding" trimmed up, hands off, for "on speed" (i.e. center of the E bracket i.e. amber donut, etc)

 

You would be amazed how many IPs let alone real pilots there are that miss understand what trim really does. I have a vid addressing exactly AOA and trim to help understand this.

 

Hope it helps. :)


Edited by Lex Talionis

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E-bracket is simply an AOA indicator. It is positioned on the HUD image relative to VV. So if AOA is constant then VV and bracket will move in lockstep. Bracket moves up and down relative to VV as AOA changes. The markings on the bracket are values of AOA relevant to landing.

 

VV is simply a pointer of where the airplane is going. Some symbology is placed relative to VV so when VV is not centered in the HUD frame, other symbols go with it.

 

Stall speed is going to be exceptionally low. Be reminded the definition of stall, the condition (AOA) at which maximum lift is being generated. This condition is not used for landing. Approach and landing will be at an AOA significantly less than stall and the airplane will fly at AOA beyond stall.

 

For landing the relevant speed (which isn't stall speed) is calculated to coincide with the desired landing AOA. The calculation is usually something like XXX knots plus Y knots for each Z of weight. It's in the flight manual. Naturally you have to go faster than this speed to remain at desired AOA for accelerated (e.g. turning) flight.

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Watch a really good video on this. I needed to understand this bracket is doing more in areas I didn't know it was and less in areas I thought it did more in. F18 seems to self trim against speed in relation to lift but when gears down it behaves more like a "normal"plane.

 

I'd argue trim MUST be used to use this bracket properly. Havnt tried but I don't think I could get proper VV and E using stick only.

 

Now that I understand. First try, trimmed up and NEVER touched stick again. Jet just plopped down on 3rd wire. This is so cool.

 

I eyeballed distance and what altitude I should be at where.

I'd like to get this down to a science and repeatable. Can anyone give specific numbers? Like this far out with e bracket trimmed you need to be this altitude etc...

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Watch a really good video on this. I needed to understand this bracket is doing more in areas I didn't know it was and less in areas I thought it did more in. F18 seems to self trim against speed in relation to lift but when gears down it behaves more like a "normal"plane.

 

I'd argue trim MUST be used to use this bracket properly. Havnt tried but I don't think I could get proper VV and E using stick only.

 

Now that I understand. First try, trimmed up and NEVER touched stick again. Jet just plopped down on 3rd wire. This is so cool.

 

I eyeballed distance and what altitude I should be at where.

I'd like to get this down to a science and repeatable. Can anyone give specific numbers? Like this far out with e bracket trimmed you need to be this altitude etc...

 

Check out Lex's videos on Case 1 recoveries. The general numbers are on-speed @ 600ft and ~1.2 miles abeam or the 180. ~450ft at the 90. ~370ft crossing the wake. All of this should be on-speed.


Edited by erautour
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