F/A-18 E/F speed brake

[Octan]

Hi,

Looking for pictures of aerodynamic brakes open F/A-18 E / F, I'll be grateful for the help :)

[Andre]

Super Hornets do not have speed brakes.

Do you mean the spoilers on the LERX..?

Cheers,

Andre

[Rank11]

If the spoilers on the LERX are not used as speed brakes, what are they used for?

[Andre]

If the spoilers on the LERX are not used as speed brakes, what are they used for?

Dumping lift by breaking up the airflow.

It's what spoilers generally are for.

Cheers,

Andre

[dylan]

Andre that was the most rude answer anybody could have given. shame on you

the man was asking for some information and all you could come up with is to attack his lack of experience and knowlege of the wording used.

By the way if you had bothered to read the post he asked about "aerodynamic brakes" not "speed brakes".

many different aircraft manufacurers use different terms for essentially the same components. so someone unfimilliar with the superhornet will most likely not be aware of the name Boeing is using for a particular component, unlike the fanboys that spend all thier time on ARC.

in the future I would suggest that if you do not have any real answers or anything constructive to add to a conversation please do not answer.

Edited March 12, 2013 by dylan

[CF104]

Dumping lift by breaking up the airflow.

It's what spoilers generally are for.

Cheers,

Andre

Actually the LEX Spoilers are only the name of the control surface. They function as a speed brake in Auto-Flaps Up mode and also provide augmentation of nose down control in high AOA conditions.

A good read on the F/A-18E/F flight control system... Click Here

As for photos of the LEX Spoilers they are hard to find due to the flight regime they're used in.

Here's one....

Growler Landing

Cheers,

John

[Rank11]

Dumping lift by breaking up the airflow.

It's what spoilers generally are for.

Cheers,

Andre

So if they are only to dump lift, does that mean they are only allowed to open upon landing? I could have sworn I have seen pictures of them deployed in flight. I am just curious what the purpose would be if not to act as a speedbrake when opened in flight. Are they some sort of direct lift control?

[rightwinger26]

what exactly were you looking for in a picture?

[ALF18]

So if they are only to dump lift, does that mean they are only allowed to open upon landing? I could have sworn I have seen pictures of them deployed in flight. I am just curious what the purpose would be if not to act as a speedbrake when opened in flight. Are they some sort of direct lift control?

Anything that decreases lift can act as a speed brake as well. Airliners and business jets have spoilers that are used to lose speed and altitude. If you decrease lift by opening up the spoilers on the top surfaces of the wing, you will lose altitude unless you increase your angle of attack. Increasing angle of attack will increase induced drag (drag due to the production of lift), which slows down the aircraft unless more power is applied. So spoilers indirectly act as airbrakes.

Apart from the lift reduction, the spoilers on a Super Hornet (or any aircraft for that matter) also increase drag. There is increased drag from the larger cross section, and drag from the turbulence created around and behind the spoiler. So even a control surface that is designed as a spoiler will also increase drag - very much similar to the way that flaps increase lift but also drag.

Thanks to CF104 for posting the Super Hornet FCS explanation. I will read it carefully, with much interest. Fly by wire systems are simple to use (I know, I've flown 1,200 hours in a CF-18), yet exceptionally complex in design and function. A beautiful example of how computer programming and hardware have combined to make flying an aircraft easy, allowing the pilot to concentrate more on deploying weapons and staying alive than simply trying to avoid going out of control.

I also have to add to what dylan said, by seconding the opinion that it was a rude reply by Andre. Let's not be arrogant and nasty for no apparent reason on this forum. It should be a place that those who are not experts can ask and get patient, helpful answers to honest questions. There are many other places on the internet (like You Tube) where people flame each other for no better reason than they are bored.

ALF

[Andre]

Andre that was the most rude answer anybody could have given. shame on you

Eh... and why, exactly..?

No snideness was implied. I merely mentioned that those are spoilers, not speedbrakes, and that spoilers are in general used to dump lift.

Short, concise and to the point.

Cheers,

Andre

[Andre]

So if they are only to dump lift, does that mean they are only allowed to open upon landing? I could have sworn I have seen pictures of them deployed in flight. I am just curious what the purpose would be if not to act as a speedbrake when opened in flight. Are they some sort of direct lift control?

As mentioned by others, the Super Hornet is one of the few aircraft without speedbrakes per se.

On aircraft like the A-4, F-4, F-14, F-111 etc.: yes, the spoilers *generally* only come out to play during landing.

On the SH, the rudders act as speed brakes as well by deflecting them both inward. This is also not generally done by other twintailed aircraft.

HTH,

Andre

Edited March 12, 2013 by Andre

[Andre]

I also have to add to what dylan said, by seconding the opinion that it was a rude reply by Andre.

Agian - no rudeness implied. '

1) English is not my native tongue and 2) I do not always have the time to write at length.

Cheers,

Andre

[B2Blain]

So if they are only to dump lift, does that mean they are only allowed to open upon landing? I could have sworn I have seen pictures of them deployed in flight. I am just curious what the purpose would be if not to act as a speedbrake when opened in flight. Are they some sort of direct lift control?

I saw an inflight video on YouTube recently of either type SH or the Growler and the LEX spoilers deployed in what looked like a modern to high G turn. The camera was mounted on the ACS coaming facing rearward.

[Rank11]

Eh... and why, exactly..?

No snideness was implied. I merely mentioned that those are spoilers, not speedbrakes, and that spoilers are in general used to dump lift.

Short, concise and to the point.

Cheers,

Andre

Andre, though the answer was short, it missed the point, since the main purpose of symmetric spoilers in flight is to slow the aircraft down. Yes, a spoiler's literal action dumps lift, but that action's purpose is to perform as a speedbrake when deployed symmetrically, as explained to you already by ALF18. I fly the EMB-145 in real life, when I read your remark that the there are no speedbrakes on the superhornet, the first question that popped into my 11,000 hour flying time mind was, what the heck are those spoilers for then? CF104 gave a really good answer as to the usage of those LERX spoilers on the SuperHornet, and their use includes that of being a speedbrake. On the EMB-145, we have a pair of spoiler panels on each wing, and yes, their literal action is to dump lift from that portion of the wing they sit at. By their dumping of lift, they actually perform two separate functions. When the two outboard panels are deployed in flight, they perform the function of a speedbrake, and are even labelled as such on our center pedestal. When all four panels deploy automatically on landing upon weight-on-wheels, they perform the function of a lift dump. So Andre, as you can see, those spoilers may have one name, but many purposes. Speedbrakes being one of them.

Edited March 12, 2013 by Rank11

[ALF18]

I have flown the F/A-18E simulator in St Louis (at Boeing). There is a switch on the throttles that is used to slow down the aircraft. I don't know, but I strongly suspect the pilots call it the "speed brake" switch. It is in the same place as the speed brake switch on the legacy Hornets.

Fly by wire systems are what I teach my students at the aviation college where I work, PFM. The P is for Pure, the M is for Magic. Fill in the rest using your imagination.

What I mean by PFM is that the pilot never knows for sure what the speed brake switch will do in a Super Hornet, just as I never knew what the flight controls would do when I pushed the stick to the left. What the pilot does when moving the controls is he asks for a reaction from the aircraft. In the case of "stick left", he is commanding a rolling moment to the left. The FCS will do whatever it takes, given a multitude of factors like CAS, AOA, roll/pitch/yaw rates, static air pressure, air density, air temperature... and lots of other things, to produce the requested result - a rolling moment to the left.

In the case of the Super Hornet, the pilot will want to slow down fast, so he thumbs the speed brake switch aft. The FCS then will decide what action to take - raising spoilers on the LEX, or splaying the rudders outward, or toeing them in, or some combination of the above - the point is that while the control surface may not be called a speed brake, it shares the duties of a speed brake.

Anyone who took 3 minutes to read 2 pages of the linked document would find the following:

The F/A-18E/F is a growth version of the F/A-18C/D but

with additional control effectors (leading edge extension

(LEX) spoilers) and increased multi-axis integration of the

existing flight control surfaces as well as a fully integrated

speedbrake function (making it possible to delete the

heritage Hornet “dedicated†speedbrake control surface).

So no, it doesn't have "speed brakes" per se, but it certainly has a "speedbrake function", and the spoilers on the LEX (not LERX in a Boeing product) are part of that function.

ALF

[parche]

There is a thread around here somewhere that had some awesome pictures of these spoilers in action... even a rear shot. I haven't been able to find them yet, but I think they were Dave Brown's pics. I'll keep looking.

Cheers,

Dave

[rightwinger26]

I don't know, but I strongly suspect the pilots call it the "speed brake" switch.

yes, its still called the spedbrake switch, its on the right throttle grip next to the comm switches

[Octan]

Exactly, I mean those flaps on the LEX

[B2Blain]

BTW - can anyone explain why when Super Hornets/Growlers are parked and have their wings folded that the majority of the time the ailerons are in trail but there rare those rare instances when the ailerons are in the extended position? The inboard leading and trailing edge flaps are always in the extended position when parked.

I've watched videos of SH landings on carriers and the SOP seems to be for the pilot to retract leading and trailing edge flaps, fold the wings, and then park. Someone mentioned previously that deck crews push the ailerons in to save space on the deck. But I am not so sure that is the best explanation. I am wondering if the pilot parks the jet with flaps retracted. Hydraulic pressure is released from the actuators and then the flaps droops. The out wing was folded in the retracted position and the leading edge flap and ailerons are in the vertical position so they do not droop down. Could the instances where the aileron is in the extended position be explained by the pilot not retracting flaps on landing and parking in that configuration?

Can anyone confirm what is happening? I am trying to determine how I should position the ailerons on my current super hornet build.

Thanks!

[rightwinger26]

The majority of the time on the beach, the TEFs are in auto when they land. Normal procedure when the bird gets to the line, is to shut down one engine, flaps to full to check switching valve operation, then shut down the other eninge. In some cases, such as the jets going through the fuel pits before coming to the line, the wings are folded for safety reasons, so when the bird gets back to the line, and the TEFs are set to full, the ailerons stay streamlined. If the wings are folded once the TEF are in full, the ailerons will stay dropped. Now there are times, that if the TEFs are full and the bird has to go in the barn, or in the paint hangar, we will turn the jet to streamline it, then fold the wings. Flight control surfaces dont drop on supers like they do on Babies with lack of Hyd pressure, so the TEFs will stay up on thier own for a long time. With Babies, on the boat, if the aileron locking pin doesnt engage, the ailerons can move, so yes, we do puch them to get them back to streamline, or if the wings are spread and we have to fold the wings electrically, we push the ailerons up prior to folding to they dont damage the TEFs. On Supers you can fold away, the ailerons won't hit the TEFs.

Billy

[Octan]

So if I understand I have no possibilities to make these flaps / spoilers were open at a standstill?

[Joe Hegedus]

It's pretty unlikely that you'd see them open on a static jet on the ground, but if you want to open them up, it's your model. Build what you want, the way you want to...

[rightwinger26]

the only time they are really open on deck is during maintenance, or during a launch procedure during 4 down, launch bar extended, hook down, IFR exteneded and speed brakes open.

[Octan]

So now I just need to find a specific photo :/

[rightwinger26]

no photo realy needed, LEFs, and TEFs at half, rudders toe'd in, horizontal stabs with the *** end up, launch bar down, IRF out, tail hook down, speed brakes out, ECS scoop out. If you want to make it a dio, pilot in the seat, one troubleshooter checking the hook, and another checking either the launch bar, ECS scoop, or pitots, and a plane captain giving the hands off signal to the pilot