787 First Flight - Signs of Trouble Ahead?

[RumourMerchant69]

While watching the 787 first flight yesterday I noticed that the outboard ailerons appeared to both be deflected negative to quite a noticeable extent.

Now it could just be an optical illusion because of the high deflection of the flaps, but is it possible that this is a load alleviation measure (shifting the lift distribution inboard to reduce wing root bending moment)? Am I being paranoid, or does that imply that the recent repairs haven't solved the wing root joint problems, and that they are having to keep the wing inboard loaded in order to satisfy the authorities?

I hate to be a conspiracy theorist (I really do) but given the recent problems and extensive delays already faced, I imagine there was huge pressure on Boeing to get it in the air before the end of the year, even if all the problems haven't been resolved.

My question is this - can anyone give me a more rational explanation for the aileron deflection at take-off? And if not, then do we really believe that Boeing will achieve a first delivery in 2010, especially given the extremely tight flight test programme?

For the sake of the industry I hope I am wrong....

[BarbiesBoyfriend]

Must admit that to me the dihedral/ upsweep seemed quite large.

Especially for a very light aircraft. Might just have been the camera angle but to me it looked like the wings were really curved, almost as if they were a bit too flexible.

At max weight the tips would be getting intimate with each other at this rate!

Is there some film of it straight and level?

[daikilo]

Just checked various take-off videos and I suggest that ailerons were probably in neutral position.

I note that flight ~never exceeded 13000ft nor ~230kts. These limits could probably be achieved with gear down and without pressurisation.

That said, its always good to see an airplane where it belongs, in the air.

[kijangnim]

Greetings,
May be Both Aileron drop down by design to increase lift (Airbus use it on the A330 For Takeoff , not on all flap position ):ok:
BTW where is the VDO available I havent seen anything

[Deltabravowhiskey]

Especially for a very light aircraft. Might just have been the camera angle but to me it looked like the wings were really curved, almost as if they were a bit too flexible.

Nope that is quite intentional to have the wings flex upward like that. In fact all the new Boeings coming out will have an amount of flex that when under full load will rise significantly above the top of the fuselage.

Just wait for the flight of the 747-8 when it comes to upward sweep.

FYI, high upward wing sweep has been used before with great success and superior efficiency!

http://farm4.static.flickr.com/3623/3376927655_23e4e213fd.jpghttp://www.flightglobal.com/blogs/flightblogger/ba787_sm.jpg

[riche_777]

Upward Sweep Wing.... In 787 ,, And The Inward Bent Ailerons R Quite Prominently Visible But If U Look Closely The Root Joint Wing Problem Is Already Taken Care.... Example Of Upward Sweep / High Sweep Are Prominent From Examples Of Crtitcal Wing Like Tht Of The Challenger 650

[Captain Airclues]

I noticed that the outboard ailerons appeared to both be deflected negative

This has been used before. The Super VC10 had switchable 'Aileron Upset' at high weights to reduce wing loading. One of the few things that I remember about the VC10 was that it had to be switched off when climbing through FL240.

Dave

[SMOC]

Both I/B and O/B ailerons are flaperons, they also deflect to the full up position with spoiler activation on touch down.

Photos: Boeing 787-8 Dreamliner Aircraft Pictures | Airliners.net (http://www.airliners.net/photo/Boeing/Boeing-787-8-Dreamliner/1626337/L/)

[SantasJetPack]

You're onto something Rumour Merchant! I didn't notice this initially but its clear on the video. They must be really concerned about the wing root strength on that first aircraft to fly with ailerons up. Normally they are deflected down to give improved span loading and so improved L/D critical for low noise at Take-off...

[bearfoil]

So if they are indeed flaperons, but act as spoilers on rollout........

"flail"- erons?

Love the stealth mixers on the aft nacelles.

[PEI_3721]

Perhaps of greater concern – at least of interest at this early stage, is the apparent rapid activity of the elevators during the climb out.
This could have been auto stabilisation, if so then the system was working hard and might not aid the longevity of the control actuators.
If the rapid oscillatory motion (small amplitude) wasn’t stabilisation, then supposedly it was an interesting response to manual control input.

[AirRabbit]

If memory serves correctly, the MD-11 necessitated "drooped ailerons" to be able to appropriately spread the forces along the wing ... at least for takeoff ... and I don't recall about the remainder of the flight envelope. But, unfortunately, they didn't initially account for the additional lift/drag from the drooped ailerons and the resultant fuel burn ... and that led to other circumstances ... and so on.

[captjns]

May be Both Aileron drop down by design to increase lift (Airbus use it on the A330 For Takeoff , not on all flap position BTW where is the VDO available I havent seen anything

Perhaps a carry over from the 767.

[Brenoch]

bearfoil;

Surely "flailers"

[B-HKD]

The drooped ailerons on the MD-11 where part of a PIP. Ultimately to increase MTOW and thus payload/range.

[Volume]

Was one of my first observations also, Boeing switched from their "old" flap philosophy to much smaller and less slotted ones (as Airbus does since A320), but does not compensate for the lower lift by aileron droop. Was a little strange to notice.
Load reduction may be one issue, the other one that came to my mind was lateral controlability. More negative ailerons give better lateral stability and higher aileron efficiency. I am still curious how the raked wingtips with no leading edge devices on a large portion of the outer wing will perform during low speed test.
Maybe it was a precautonary measure to keep a larger stall margin for the outer wing before all aerodynamic asumptions have been verified ?
I am quite convinced that later on we will see aileron droop on the 787.

[Spooky 2]

The current B787 design includes aileron droop. All this speculation is amazing. Where do you guys come up this stuff?

One thing really interesting on the 787 is a system called Cruise flaps where it squeezes out a small undetected amount of trailing edege flaps and aileron droop to incrase the camber of the wing, thus enhancing performance. (Only in level cruise flight) Also another system called Auto Drag will assist the pilot when approaching the GS from above. Need flaps 25 or greater for it to work and it does this without pilot imput. Washes out at 500 AGL.

[Volume]

Surely the B787 design does include aileron droop, however as all the images clearly showed, it was deactivated for the first flight. In many pictures it even looked like "negative droop" was selected.
http://www.flightglobal.com/blogs/flightblogger/ZA001-inflight-tail.jpg
Only flight testing will show the optimum amount of aileron droop for each flap setting, and when the aircraft is delivered, it will for sure include this feature.

[John Farley]

Only flight testing will show the optimum amount of aileron droop for each flap setting, and when the aircraft is delivered, it will for sure include this feature.

If you had said confirm I would agree. Tunnels and CFD are very good at predicting such matters these days.

As for rapid small movements of the tailplane I would think it unusual if a FBW design did not respond thus during flight even given zero pilot input - unless one was talking about absolute flat calm conditions.

[Rainboe]

Can we get this straight? Are we talking about aileron 'droop' or 'upfloat'? Upfloat I can understand. But I do find it extraordinary that a correspondent thinks he has spotted design flaws from a company like Boeing on a maiden flight. Arrogance in misplaced self-confidence! He could have asked rather than approach the issue so negatively (and make a plonker of himself!).

Aileron upfloat would be expected on a very high aspect-ratio wing like this. The VC10 had it 45 years ago designed in, cutting in and out at 24,000' I remember, to alleviate mid span wing bending moment. I don't know if that was the first in a big jet. But Boeing are designing wings now optimised for high altitude, long range cruise, very long and slender and bendy! No wonder they bend so much. The 747-400 and 777 wings bend more than previous models like the 747 100-300, and even the 737-800/900 are very bendy. It's how they are now.

[RumourMerchant69]

Can we get this straight? Are we talking about aileron 'droop' or 'upfloat'? Upfloat I can understand. But I do find it extraordinary that a correspondent thinks he has spotted design flaws from a company like Boeing on a maiden flight. Arrogance in misplaced self-confidence! He could have asked rather than approach the issue so negatively (and make a plonker of himself!).

If you are referring to my comment that started this thread then I think it has been totally misinterpreted. My observation was a noticeable negative aileron deflection (clearly visible in the videos) and a question/theory as to why that might be the case. It is not uncommon for first test flights to be performed with some sort of reduced flight envelope, particularly where structural certification testing is not yet complete due to re-work and repairs (as is the case here I believe), but it is not always as obvious as using load alleviation in this way.

Note that I am not suggesting that this deflection is an inadvertant result of a design flaw - quite the opposite. In modern aircraft it is possible to intentionally use ailerons, flaps spoilers in various combinations to alter spanwise loading. I was simply observing that it looks like they are doing that to reduce the load envelope for early testing. My question was why they need to protect the envelope to that extent.

If making an observation and bothering to question 'why?' with a few fairly rational supporting statements makes me a 'Plonker' as you so eloquently state, then I will wear that badge with pride.

[Love_joy]

Rumor Merchant,

I believe the point Rainboe was trying to make, was that your original post seemed to focus on the negative, rather than the positive. Your own post title reaffirms this; "787 First Flight - Signs of Trouble Ahead?"

Plonker....

[Rainboe]

It is still not clear what you mean, what does 'deflected negative' mean? Deflected down? That would not be right at all. I assume it means 'upfloat'? The reasons for that are well documented. Your first post was full of innuendo that Boeing had made some design error with wing and aileron design. Anyone famliar with later 737s, 747s and 777s will be familiar with the new wing design preference and the reasons for wing bending. Inflight, the 737 wingtips are looking at each other over the top of the fuselage. A simple question would have extracted an answer for you instead of 2 paragraphs devoted to a possible Boeing design disaster area, which is utter nonsense.

A magnificent looking plane with real technical innovation. It will make a fitting partner to the A380 for the heavy stuff for the next generation.

[ska-bearbaiter]

Nope, thats not the right one either.......its on Terms and Endearments...you know,its the thread about your company

[Kirks gusset]

Signs of trouble ahead! .. I saw a Clio with a fat exhaust that converts petrol to noise.. maybe Renault should recall them all...Whilst the debate on flight controls and aerodynamic forces is worthy of a thread, I agree with Rainboe, let's not descend into nonsense and speculation

[FA10]

Refering to your original post, RumourMerchant69:
Correct me if I am wrong, but your suggested load alleviation would not change anything on the bending moment on the wing root!
If you deflect the ailerons upward, the loss of lift on the outer wing has to be compensated by the inner part - the resulting bending moment on the root is exactly the same! With your suggestion you can only change the bending moment over the wing spar(s).
If Boeing had planned to ease the load on the wing-fuselage connection, a reduction in takeoff weight would have helped them - instead they reportedly took 10 tons of water ballast on board.

[wonderboysteve]

Is it at all possible that you are confusing shear force and bending moment?

[xetroV]

Might just have been the camera angle but to me it looked like the wings were really curved, almost as if they were a bit too flexible.

Artist impression versus first flight photo...

http://www.flightglobal.com/blogs/flightblogger/ba787_sm.jpg http://www.flightglobal.com/assets/getAsset.aspx?ItemID=32065

Yep, the wing flexes as designed. :hmm:

What else did you expect?

[BigHitDH]

Where do you get these ideas RumourMerchant?

I'd think that Boeing probably have a better idea of how to design a wing than you, unless of course there is something you're not telling us (are you about to roll out a new intercontinental passenger jet from your garden shed?):eek:

Regardless, as the saying goes, if it looks right it'll fly right, and it sure looks right! I'm a little dissapointed they changed the tail from the original concept, but the aircraft as a whole looks great - it reminds me of a glider, which I suppose is the point!

BHDH.

[XPMorten]

the wings are designed to flex.
At max load (around 4 G's) they will deflect 26 feet.
The first flight was all about testing controls and check
for flutter which one can imagine can be a risk
with such an extreme bending wing.

http://www.xplanefreeware.net/morten/DOCS/flex.jpg

[spannersatKL]

Am surprised 411A hasn't joined the fray....the good old Tristar 500 had ailerons that I believe were offset upwards for take off? Also had a Load Allieviation Function like the A320 etc. But 787 looks great in flight was good to see the landing on the web cast.....a winner worth waiting for?

[Rainboe]

Correct me if I am wrong, but your suggested load alleviation would not change anything on the bending moment on the wing root!
If you deflect the ailerons upward, the loss of lift on the outer wing has to be compensated by the inner part - the resulting bending moment on the root is exactly the same!
I think this is wrong. It's all to do with moments. If you moved the total lift of the wing out to the wingtip, the same lift is still there, but the bending moment would be immense. Move the lift to near the root and the bending moment would be minute, but the lift would still be the same. Aileron upfloat moves each wing'
s centre of lift inwards and reduces the bending moment, and reduces the wing flexing moment allowing a lighter structure. The VC10 used to take it off at 24,000'- I don't know if the 787 does the same. It also helps prevent adverse aileron drag in a roll as the downgoing aileron initially moves into the general wing shape whilst the upgoing aileron initiates a downforce immediately. So no adverse yaw in a turn if you design it right.

Rather than aerodynamics, a more interesting discussion would be on the technical aspects of this aeroplane. Presumably 2 (BIG!)alternators per engine plus ELRAT? Has everything ended up being electric- no hydraulics? Obviously all planned, but single engine raising of the gear with aircon packs, and maybe flaps being raised AND tailplane being trimmed? Quite an immense demand! I expect ALL the lights would go out, and galleys load shed! And how do the brakes work? I have never seen electrical wheel brakes. Feel must be totally artificial. I just can't see how the electrical demand can all be handled at high workload times. All you need is those fancy pants screens suddenly going 'blue screen of death' on you! But I know Mr. Boeing knows his planes!

[Graybeard]

They don't address your electrical questions, Rainboe, but these nuggets from the Rockwell Collins news release do give some insight:

Rockwell Collins serves as the systems supplier for the Boeing 787 flight deck display system, crew alerting system, pilot controls, communication and surveillance systems, and the core network cabinet. Rockwell Collins also provides the common data network for the airplane's Common Core System..

An integrated display system featuring five 15.1-inch diagonal LCD displays, as well as dual LCD head-up displays (HUD). The Rockwell Collins Head-up Guidance System (HGSTM) provides the most advanced display capabilities available in the air transport market, including primary flight, advanced navigation and complete crew alerting functionality. The system utilizes cursor control devices and a multi-function key pad for data entry and retrieval.
The latest generation of pilot controls with a control stand that includes auto throttles, and pitch, roll, yaw and primary flight controls, as well as their interfaces to the aircraft's fly-by-wire systems. The modular design of the pilot controls will simplify installation and maintenance. This new system meets Boeing's objective of providing operators with a look and feel similar to the Boeing 777, while achieving significant weight savings.
The Core Network, offered as standard on the 787, which plays a key role in Boeing's objective to 'e-enable' the entire aircraft. Utilizing commercial open standard computing servers and networks, the Core Network hosts a wide range of third-party applications and manages onboard information flow to improve airline operational efficiency.
The Common Data Network (CDN), which advances Rockwell Collins' leadership as a supplier of advanced networking technologies. As a key component of the 787 Common Core System, the CDN is a high integrity, bi-directional fiber optic and copper network that uses ARINC 664 protocols and standards to manage the information flow between the aircraft's onboard systems. Based on commercial Ethernet technology adapted to the avionics environment, the integrity and deterministic characteristics of Rockwell Collins' CDN allows systems integrators to utilize this network for systems requiring a high level of data criticality. The CDN offers significant improvements over current generation data buses including expanded connectivity, higher data rates and significant reductions in aircraft weight when compared with point to point topologies...GB

[violator]

Rainboe is right, for a given total lift the bending moment at the root is reduced if the lift distribution is moved inboard.

The 787 has a 2E/3H architecture. It has three hydraulic networks (Left - engine-driven pump and electric (demand?) pumps, same for Right, Centre driven by two electric pumps). Each engine has two 250 (!) kVa starter/generators, the APU has two 220 kVa starter/generators. The RAT provides both hydraulic (to Centre system) and electric power.

Because of all the various electrical loads it has a 230Vac network, a 270Vdc network, a 115Vdc network and a 28Vdc network.

Spoilers and stabilizer actuator can be electrically driven following a full hydraulic loss, making the 787 controllable in the event of losing all ship-wide hydraulics (like the A380). The brakes are electrically driven.

A potential issue for airlines, because the engines are started using the electrical starter/generators you need a lot of power to get them going. If the APU is u/s you need three good GPUs to start an engine.

[XPMorten]

Rainboe, it's got 6 generators, 2 on each eng, 2 on the APU.
1 Main bat, 1 APU bat, RAT. 4 main buses.

(EDIT a tad late)

[RumourMerchant69]

Ok I will try and clear things up a bit (again). My 'outrageous speculation' of structural problems is not speculation at all - it is in the public domain.

News article about repairs work prior to first flight, this was due to de-lamination observed during the static testing performed in 2008:

No verdict yet on completed tests to 787 wing repairs - SmartPlanet (http://www.smartplanet.com/technology/blog/thinking-tech/critical-boeing-tests-to-787-wing-repair-complete-no-verdict-yet/2256/)

Note the quote "The aircraft did go to limit load as intended" however at that point analysis was still ongoing. I certainly haven't found anything more recent about the results of the test. It is possible to perform the first test flight even if the results were not that favourable (after all you are not going to come anywhere near limit load on your first test flight), but the authorities will almost certainly ask you to demonstrate that the flight envelope is being limited to mitigate the risk.

Flying at reduced weight and limiting the types of manoeuvres performed can help limit the envelope, particularly for structure where the critical load cases are the manoeuvre load cases, but for areas driven by gust cases it can be much more difficult to protect in this way. In fact adding ballast in the wings can help mitigate for this by increasing inertia and providing some bending relief. Another way to protect for the gust cases is to keep the wing inboard loaded to reduce the bending moment.

Now maybe you can understand why my observation that negative aileron deflection (yes negative means up - thats the convention) may have been employed to inboard load the wing. This would reduce the bending moment at the root joint and hence the load at the crown fittings (these are effectively transferring the bending moment into the centre wingbox structure as a couple of two running loads - compressive at the top skin joint and tensile at the bottom skin joint.) If you reduce the bending moment you reduce the load on these fittings.

I am not suggesting there is any new problem, just that the use of load alleviation may be a symptom of a well known existing problem, and was wondering if anyone had any 'information' that might better explain the aileron position at takeoff. You will note my post title was "signs of trouble ahead?" not "signs of trouble ahead!" There is a very big difference.

I am in no way trying to belittle the achievement - the 787 is a beautiful aircraft, and a revolution in systems and structure design and manufacture, and will certainly be a great success. My question was really around whether the use of alleviation suggests that there may be further delays before first delivery, or if there is another explanation.

Note that I do not think the wing deflection is a design flaw - it is a design feature, and a beautiful one at that.

[BigHitDH]

I can only see one real issue with this aircraft - lightning protection. Seems the FAA have relaxed their criteria for lightning resistance in line with the expected performance of the composite structure of this aircraft. I wonder if this might come back to haunt them?

[AerocatS2A]

I am not suggesting there is any new problem, just that the use of load alleviation may be a symptom of a well known existing problem, and was wondering if anyone had any 'information' that might better explain the aileron position at takeoff. You will note my post title was "signs of trouble ahead?" not "signs of trouble ahead!" There is a very big difference.
Not really. It just allows you to insinuate the same thing while being able to weasel out of it when being questioned by saying "but look, there's a question mark, I was just asking a question!"

RumourMerchant69, are these signs he is a dishonest coward?

See how it works? I'm just asking an innocent question.

[XPMorten]

It is possible to perform the first test flight even if the results were not that favourable (after all you are not going to come anywhere near limit load on your first test flight), but the authorities will almost certainly ask you to demonstrate that the flight envelope is being limited to mitigate the risk.

30th of november ZY997 successfully completed the static test with
the new wingbox design. The "2C test" exceeded the 100% load (2,5G) which
is required by the FAA for first flight.
They recreated the conditions that led to the delamination this summer.
The ultimate 150% load test is expected spring 2010.

http://www.flightglobal.com/blogs/flightblogger/ZY997wingflex_560.jpg

XPM

[parabellum]

When they did the same test on the B727 the wings nearly met over the hull before they snapped, then it could be heard all over the airfield!

Did the A380 pass this test first time round?

We are in danger of being somewhat blinkered here, new material, a different picture altogether, not at all reasonable to compare the visual image of the 787 wing stress test with wings not constructed from the same material or to the same design.

[Denti]

Do you mean the 150% limit load test? nope, the A380 didn't pass that the first time round either, however it did pass the tests until 148% on the first go unlike the 787 who delaminated below 120% load (and still hasn't been retested above that).

That said todays aircraft development certainly tries to design exactly on target and not one bit above it, which is good business sense but is walking a very very fine line. Still think the 787 is a beautiful aircraft and hope all goes well with the very ambitious flight test program. Too bad the delay is so large now that our whole order of that plane is under reconsideration now.

[barit1]

Assuming that by "negative deflection", RumorMonger means upward aileron deflection:

1) Yes, the structural effect is to move the center of lift inboard, reducing the bending moment on the center section; perhaps not uncommon for first flights, as a means of introducing extra conservatism.

2) Another effect is on handling qualities: raised outboard ailerons would help insure the wing root stalls first, so the ailerons remain effective throughout the stall.

Further, on a swept wing, keeping outboard lift available aft of the CG aids a nose-down pitching moment to aid stall recovery.

I wouldn't expect this to be a permanent feature of the production airplane, but merely "belt and suspenders" insurance during early flight test.

[violator]

barit1,

I don't think Boeing will rely on presumably a software function for aerodynamic stalling characteristics. During low speed, low loading I suspect the alleviation won't be active.

I also think that the 787 will use this load alleviation on production aircraft. It will provide a useful reduction in loads which you could take credit for in wing root design.

[ZAGORFLY]

the only one Bugatti Plane had the similar system :
negative flaps on cruise to reduce drag and auto deployment of positive (down) flaps according the speed . Clever!

[deSitter]

What's the current thinking on Vince Weldon's "danger danger" alarms? He's anything but a crackpot - worked on the 727 flap system, Apollo CSM engine thrust structure, and Shuttle structures - IOW he knows structures! However Boeing fired him, and there is the possibility that he was just being old and cranky - however I have the utmost faith in engineers, and he's been a good one. What say ye?

-drl

[bearfoil]

Denti

Saw the limit load test with me own eyeballs, 152+ % There is a video.

bear

[Denti]

Of the 787? Interesting, boeing hasn't released that information yet.

[BarbiesBoyfriend]

Maybe the aileron deflection is due to 'gust alleviation', a la U-2?

[XPMorten]

Would make sense going all the way unofficially at this point
to see what max load the "fix" can take since this is new territory design.
No point in waiting another 6 months for the official test to find the "fix" didn't work.. .

[Denti]

Of course it makes sense to test the fix to the 150% mark, but i am somehow puzzled that they do not share that immediately like they did every little improvement in the past, after all it is a pretty big thing. Besides, it is of course something that has an impact on the stock market and sharing some unofficial information is somewhat puzzling at this point.

Anyway, i do hope the fix does work as intended and withstands the 150% load test, still hope to fly that plane myself at some point.

[Bullethead]

Maybe the outer ailerons were not deflected upwards, they just appeared to be as the TE flaps and inboard ailerons were all deflected downwards. The video clips I've seen are not clear enough to actually see the relative positon of the outer wing TE and the outer aileron to accurately say one way or the other .

Regards,
BH.

[vapilot2004]

What's the current thinking on Vince Weldon's "danger danger" alarms? He's anything but a crackpot - worked on the 727 flap system, Apollo CSM engine thrust structure, and Shuttle structures - IOW he knows structures! However Boeing fired him, and there is the possibility that he was just being old and cranky - however I have the utmost faith in engineers, and he's been a good one. What say ye?

Mr. Weldon Boeing's M. Jacquet? Oui? Non? Peut-etre? :}

[TURIN]

If you are referring to my comment that started this thread then I think it has been totally misinterpreted. My observation was a noticeable negative aileron deflection (clearly visible in the videos) and a question/theory as to why that might be the case.

and

Now maybe you can understand why my observation that negative aileron deflection (yes negative means up - thats the convention) may have been employed to inboard load the wing.


In what professional circles is the term "Negative Deflection" used when considering the rigging (or otherwise) position of flying controls?

I only ask as having worked in aircraft maintenance for the best part of 30 years it is not a term that I have seen commonly used. Maybe I'm missing something, but "Up/Down" or "Left/Right" have sufficed for now without causing any confusion.

Unlike the original post. :confused::ok:

[XPMorten]

The FCOM doesnt mention any symetric "up" aileron as some claim to see.
So if it's the case, it probably is some testflight precaution as mentioned.

Only mention of aileron droop is;
1. With flap and flaperons at low speed
2. Cruise flap, they deflect very minor with flap, flaperons and spoilers to vary
camber and thereby reduce drag depending on weight, Alt, speed.

[RumourMerchant69]

In what professional circles is the term "Negative Deflection" used when considering the rigging (or otherwise) position of flying controls?

In Loads & Aero for aircraft design you normally use +ve for down deflections and -ve for up deflections of any control surface (at least in my experience - might be that different companies use different conventions?)

Either way, there will be a hinge-line axis system and either up or down will be defined as positive. Makes the maths a lot easier :8

[Kerosene Kraut]

Is this the 152% LL test mentioned above?
YouTube - The Boeing 787 Delay Liner Wing Load Test (http://www.youtube.com/watch?v=bV_V4U0iX4w)

This was the Dash 18 half span wingbox.

What is the highest load test the refurbished current wing did?

[SeenItAll]

I get the impression that some contributors to this board wouldn't have been satisfied with this first flight unless unless the Dreamliner demonstrated a full roll -- like was done by Tex Johnston on the 707 prototype's first appearance.

See: YouTube - Tex Johnston (http://www.youtube.com/watch?v=X0sDN-CQZCs) and Boeing 367-80 - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Boeing_367-80)

[kijangnim]

Greetings evryone

I am currently visiting Boeing in Everett, and could see the B787 (in fact to day there is a flight at 0700 local time) and made a visit to the production lines.
Stop speculating :ouch:the bird is magic:ok:, and Boeing has all the necessary knowhow to take all the challenges, everything is new in this airplane, NO BLEED (except for Anti Ice) the B787 is an AC/DC animal, no need for fuel tranfer in flight trailing edge will extand .5 to 1 degree during flight to move the c of g, expected fuel figure to be 15 to 20 % better than the B767! engine nacelle chevron design noise reducers give better than stage 4 EPNBs and so on and so on, the bird is magic.
Weither we like it or not While people are busy speculating, Boeing is busy working
Regards:ok:

[Willit Run]

From a Boeing Field service Rep:

It was very exciting yesterday and with minimal flight squawks reported. Boeing considers this first flight one of the best ever. And that's a huge accomplishment given all of the new systems designed into this airplane.

Take that for what its worth!

[411A]

Am surprised 411A hasn't joined the fray....the good old Tristar 500 had ailerons that I believe were offset upwards for take off?

411A doesn't know anything about the 787, other than the fact that it is a tad.....late.

-500 TriStar had active ailerons for climb/cruise gust load control.
Full time.
Very clever.

[barit1]

kijangnim
trailing edge will extand .5 to 1 degree during flight to move the c of g,

How's that again? :confused: :confused:

the bird is magic

Ahhh, maybe that explains it... :D

[BigHitDH]

I think he means centre of lift. Altering the camber of the wing to effectively "trim" the aircraft, if you can call it that?

More to the point, what are the going to call these devices? Flaperators? Flims? :8

[XPMorten]

Boeing calls it Cruise Flap. One increases camber to reduce drag.

For a better understanding of the theory behind it, some reading
up on Supercritical Airfoils (http://www.xplanefreeware.net/morten/DOCS/supercritical.pdf) might help.

XPM

[barit1]

I can readily accept the advantage (within limits) of a bit more camber.

The question then becomes: Why operate without said camber? In what flight regime is it an advantage to have less camber?

Boeing may have all the answers, but are they disclosing them to we peons?

[XPMorten]

Cruise flaps are trailing-edge flaps operated at small deflection
angles for the purpose of reducing drag at offdesign conditions.
The deflection of a cruise flap results in a shifting of the low-drag
region (bucket) of the drag polar for an airfoil, as shown in Fig. 1.
Flap deflection moves the leading-edge stagnation point, which
affects the pressure distributions along the airfoil upper and lower
surfaces. Figure 2 shows that for natural-laminar-flow (NLF) airfoils,
there is a small region at the leading edge in which it is most desirable
to locate the stagnation point [1,2]. Doing so results in favorable (or
less adverse) pressure gradients over the upper and lower surfaces,
even at offdesign coefficients of lift. Without the cruise flap, either
the upper or lower surface would have experienced loss of laminar
flow at these offdesign conditions. Thus, when scheduled correctly, a
cruise flap can result in a large range of Cl values over which low Cd
is achieved. For this reason, several NLF airfoils have been designed
with cruise flaps [3–5]. Cruise flaps have also been successfully used
on high-performance sailplanes for several decades.


So basicly, automated cruise flap ensures that the wing STAYS inside
the low drag bucket for a larger portion of the flight reducing drag.
I would guess the main advantage would be whenever you are
above or below your optimum altitude or airspeed. In other words, most of the time..:p

XPM

[bearfoil]

Cruise Flap permits the addition of drag (lift) aftward of the CL, effectively displacing the cg aft, allowing the Tailplane to load, with attendant reduction in angle of attack, which reduces overall drag.

bear

[barit1]

Thank you all. Makes more sense now. :cool:

[411A]

'


Cruise Flap permits the addition of drag (lift) aftward of the CL, effectively displacing the cg aft, allowing the Tailplane to load, with attendant reduction in angle of attack, which reduces overall drag.
Hoot' Gibson tried this with a TWA 727 years ago, didn't work out so well when the FE stuck his oar in the water, and the result was a wild ride down....way down.:ugh:

[XPMorten]

A bit more details.
The system will be moving the trailing edge through a 3 deg arc,
with the edge deflecting up and down by as much as 1,5 deg either side
of a neutral setting position. It will move in 0,5º increments.
In addition, the spoilers will droop up/down to adjust the airflow around the
slot between the flap and spoiler.

It will save drag equivalent to about 450 kg weight.

[Kerosene Kraut]

Yesterday ZA001 had it's second flight. This source claims it was cut short by around three hours. Weather looked CAVOK.

Boeing 787 beginnt reguläre Flugerprobung - FLUG REVUE (http://www.flugrevue.de/de/zivilluftfahrt/fluggeraete/boeing-787-beginnt-regulaere-flugerprobung.16574.htm)

[Volume]

As can be seen in this (http://www.flickr.com/photos/moonm/4309211935/sizes/o/) picture of the second prototype, Boeing is now using aileron droop in the high lift configuration (meaning the ailerons are slightly deflected down to support the flaps in delivering the lift needed for take of and landing). This is how it is done for Airbus from A319 to A380, this is how everybody expected the 787 to be designed. Load alevation in the high lift configuration by deflecting both ailerons up as some posters assumed would not make any sense.

So finally we have learned, that the unusual upward deflection of the ailerons during first flight was an additional safety measure to have more margins for any unforseen events and is not a standard 787 design feature. The structure obviously is also capable of taking the bending moment in the high lift configuration with aileron droop. (and Boeing is confident in this by now)

case closed.