If both hyd should fail, manual reversion is available from both control wheels. If the aileron system jams, the co-pilots wheel can be used to move the spoilers hydraulically. There are balance tabs and balance panels on both ailerons.
[2.0] 737 NG, 737 MAX, & Military 737s
There are two aileron trim switches to prevent spurious electrical signals from applying trim. The fwd switch is for direction, the aft switch is simply an earth return. The above series of photographs show how the flight spoilers move with various combinations of aileron and speed brake. With speedbrake down, the spoiler simply rises on the down-going wing with aileron. With speedbrake applied, not only do the spoilers on the down-going wing rise but also the spoilers on the up-going wing fall.
Notice that even with full speedbrake applied the spoilers still rise on the downgoing wing. This property of the spoilers on both wings to respond to roll inputs is known as differential spoilers.
It only occurs when speedbrake is used which is why the roll rate is increased when speedbrake is used. Boeing recommend that speedbrake is not used below feet for this reason. NB In the bottom two photographs the speedbrake lever was only at the flight detent position but because the aircraft was on the ground the ground spoilers deployed.
This is why if you have any sort of technical problem that might be due to a faulty air-ground sensor eg QRH "Gear Lever Will Not Move Up After Takeoff" you must not use speedbrake in case the ground spoilers deploy in-flight.
You can see from the series of photographs just how much extra drag ground spoilers will give over flight spoilers. Spoilers will continue to operate with speedbrake deployed. On landing, if armed, all spoilers will deploy when the thrust levers are at idle and any two wheels have spun up or right gear is compressed.
If not armed, the speedbrakes will deploy when reverse thrust is selected. Do not use speedbrakes in-flight if you have had to manually over-ride the gear to retract it. Because with the thrust levers closed, the ground spoilers will deploy as well.
On the NG the story is a little more complex and spoiler movement varies as follows:. There is no manual reversion for the rudder. For an in-depth explanation of the rudder system click here. Yaw Damper. The is positively damped in combined lateral-directional oscillations, which in plain English means that if you set up a Dutch Roll the aircraft will gradually stop oscillating.
So the yaw damper is not required for dispatch, however it is fitted for passenger comfort. It is powered by hydraulic system B. So two were fitted to allow dispatch in case one failed. As it happened, none were required. Note that aircraft with the RSEP installed, the yaw damper test switch is inoperative shown right. The NG's saw a return to a dual system by having a standby yaw damper, note that only the main yaw damper inputs are shown on the indicator.
Yaw damper inputs are not fed back into the rudder pedals, which is why there is an indicator. However from April the indicator will not be fitted to new aircraft. The rudder trim knobs have evolved over the years. It was believed that a jump seat occupant may have inadvertently moved the knob with his foot when it was resting on the aft electronic panel.
A raised shield was also fitted around the aft end of this panel to prevent inadvertent movement of the trim controls. If both hyd should fail, manual reversion is available from both control columns.Click here for technical specifications of all versions. The was 94ft The -7 was flat rated to develop the same thrust at higher ambient temperatures than the -1 and became the standard powerplant for the Just 30 series 's were built, with 22 going to Lufthansa, 5 for Malaysia Airlines and 2 for Avianca.
It was immediately realised that most airlines wanted a slightly higher passenger load, to which Boeing responded with the Two sections were added to the fuselage; a 36in section forward of the wing and a 40in section aft of the wing, giving a maximum capacity of passengers with a 28in seat pitch. All other dimensions remained the same.
The JT8D was increased to 14,Lbs with the Six weeks later on the 5 April the series was launched with an order for 40 from United Air Lines. Development and production of the two series ran simultaneously.
Notice the short nacelles and clamshell thrust reversers. Photo: Steve Williams The original series had narrow engine pylons and smaller inboard leading edge flaps. The later series had broad engine pylons and the inboard leading edge flaps extended to the fuselage.
The MTOW of 49,kgs and MLW of 44,kgs were often limiting so Boeing made structural changes to increase these weights and called the redesigned aircraft the Advanced.
Autobrake, improved anti-skid, automatic speedbrake for RTO, automatic performance reserve and even nose-brakes became available. Again, kits were available for existing operators of the These performance improvements increased the service ceiling by 2,ft to 37,ft and the maximum cabin differential pressure was increased from 7. For many years United remained the only major US carrier to order large numbers of 's because although the aircraft was designed to be flown by 2 crew, the US flight-crew union ruled that aircraft in that class had to be flown by three crew.
United were forced to fly their 's with three crew until Air France had also been trying to order the aircraft for several years but were unwilling to because of staff opposition until after Most pilots who have flown different generations of the say that this is easily the best for handling.
Read some comments at PPRuNe. They also had strengthened floors and additional seat tracks. As a freighter it could accommodate seven LD7 88in x in palettes on the main deck plus any loose cargo in the two holds. Conversion time was approximately 3hrs but this was later reduced to about 1hr with the QC which had 12 passenger seats ready mounted on each pallet. This realistically allowed the aircraft to used for both roles allowing it to earn money around the clock by carrying pax by day and freight overnight.
Some airlines even operated them as Combi's with pallets at the front and pax at the rear. Originally designated the Corporate or the Corporatethis was an executive jet version of the and Adv, similar in concept to the current BBJ. These were either fitted with one of the many Boeing interiors or were delivered green for customer installation of special interiors. Aux fuel tanks were also fitted to give a maximum range of up to 4,nm with a 1,kg payload. This was an option available for the from Feb and included:.
The nose gear unit folds forward as the gear retracts seating into the faring in front of the nose wheel well. See photo. Fitted with an USGal auxiliary fuel tank in the aft cargo hold, giving it a range of over nm.
Maritime Patrol aircraft for the Indonesian Air Force. This system could spot small ships at ranges of nm.Plano Rd. Richardson, TX - tel: Learn More. Step inside our on-line Product Catalog to learn more about our complete offering or to view specific product drawings, performance, or specifications.
View Products. Find contact information for your local Krueger representative. They will be able to to answer questions as well as provide pricing and availability. Locate Your Rep. Krueger has one of the largest selections of published articles and white papers that cover a variety of topics, from air distribution to equipment. View White Papers. Are you looking for a specific product but don't know the Krueger model? Let us help you identify it through our manufacturer product cross reference program.
View Cross Reference. Request a Copy. Comfort Calculator. K-Select Air Distribution Products. Revit Blocks. Connect with with us on LinkedIn for company and industry news and announcements. Connect Now. Learn how different products perform by viewing our product smoke demonstrations. View YouTube Videos. Want to be notified of new product releases and other exciting updates?The company is now moving forward on the fourth generation, the " MAX" series.
Although the was purchased mostly by commercial airlines, it was also obtained by military forces -- not just as transports but for other roles, such as the US Air Force "TA" navigation trainer, based on the This chapter discusses the third and fourth generation s, as well as specific military variants.
Inthe company kicked off the "Next Generation X" program. As the program emerged, the NG machines shared several significant improvements:. Four basic NG variants were built. The first to fly was the "", originally "X", which was to replace the and could be fitted with a maximum of seats. Certification and initial deliveries took place later in that year.
It would lead to specialized subvariants, see below. The second was the "", originally "X Stretch". It had a length of Initial flight was on 31 Julywith introduction to service in the spring of The "", originally "X", was the third, intended to replace the Initial flight was on 22 Februarywith introduction to service before the end of the year.
Incidentally, Boeing never offered winglets as a purchase option on the The fourth, the "", didn't fly until 3 Augustwith introduction to service in the spring of It was the biggest built to that time, with a length of Actually, at the outset the could only carry a maximum of passengers due to regulatory issues. It led to "ER", introduced inwhich could handle a full passengers, thanks to the addition of two more emergency exits.
The ER could also be obtained retaining the maximum of seats and without the additional emergency exits, but with additional tankage for improved range. Of course, the airframe was reinforced to handle higher MTO weight. It proved surprisingly popular. The IGW airframe also led to the "C" and "QC" combi freighter aircraft; and then the extended-range "ER", featuring additional fuel tankage.
It could be configured for 48 seats in a premium configuration, or up to seats in a traditional two-class configuration. Deliveries began in With a new generation of s coming online -- see immediately below -- the NG series is now faced with gradual obsolescence. As a result, Boeing has been promoting a " Boeing Converted Freighter" -- with cargo door, reinforced floor, and other freighter kit -- the initial redelivery of a BCF taking place in Aftermarket vendors are offering similar conversions.
Inone in four of the world's large airliners were s; 6, had been ordered in total, with more than 4, in service with over airlines; and over a thousand were in the air at any one time. Of all the commercial jetliners sold by Boeing and Douglas, a good third of them were s.
Ironically, the 's old rival, the DC-9, had evolved through the acquisition of McDonnell Douglas by Boeing into the "Boeing ", and then had ceased production. Late in the first decade of the 21st century, Boeing was focused on development of the "" advanced technology twinjet, leveraging off technology to also update the jumbo jet to the "". The company had considered development of an all-new replacement for the -- but given customer satisfaction with the and a short-term demand for something better, Boeing decided to give the a flavored facelift as well.
Rival Airbus had been similarly considering a new-design replacement for its competing A, but decided to introduce an updated version, the "A New Engine Option NEO ", instead, with delivery from Boeing couldn't afford to leave the field to Airbus over the longer interval it would have taken to develop a new machine that could only be an incremental improvement over an updated one -- and so decided to have the next-generation " MAX" flying byand in the hands of airlines by At the outset, Boeing planned three models of the fourth-generation MAX: the " MAX 7", " MAX 8", and " MAX 9" -- updates of the, and respectively, all of similar configuration, but with different capacities.
Aviation Stack Exchange is a question and answer site for aircraft pilots, mechanics, and enthusiasts. It only takes a minute to sign up. I mean why using Krueger flaps in some aircraft instead of using slats all over the leading edge? There are different types of Krueger flaps used, with increased efficiency coming at the cost of increased complexity. The simple ones are basically flat panels that folds out from the wing lower surface into a very steep, deployed position and seals against the wing leading edge; though these are extremely simple, they don't offer much in the way of stall protection.
The next type has large folding 'bull' nose that offers increased performance at the cost of slightly increased complexity. This type of flaps is used in B, B, and inboard of B, as shown in the figure below:. Image from aviation. This means that simpler Krueger flaps are used in the inboard with slats in the outboard region, so that the flow remains attached in the outboard regions at higher angles of attack compared to the inboard region.How It Works Flight Controls
Many large airliners, particularly Boeings, use Krueger flaps closer in to the fuselage and slats further out on the wing. This is primarily because slats resist a stall more effectively, so by placing Krueger flaps on the forward parts on a swept wing and slats on the rearward sections, it encourages a more balanced, controlled landing stall.
Another reason to use Krueger flaps is that they are lighter, both with the equipment itself and with its actuators, and can be used on thinner wings that are too thin for slats. Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. What are the benefits of using Krueger Flaps?
Ask Question. Asked 4 years, 2 months ago. Active 4 years, 2 months ago. Viewed 7k times. Active Oldest Votes. This type of flaps is used in B, B, and inboard of B, as shown in the figure below: By Arpingstone - Photographed by Adrian Pingstone in August and released to the public domain.
However, the main problem is that the mechanism is exceptionally complex, as can be seen in the figure below.
As a result not many aircraft use these.Ed Hill discovers how high-lift assembly specialist, Asco has developed a new Krueger flap from composite materials. Civil aircraft designers are continually improving wing designs with natural laminar flow NLF sections.
However, there is an inevitable trade-off between the smoothness of wing surfaces for cruising speeds and movable high- lift devices such as flaps and slats needed to generate lift at take-off and landing. These moving elements of modern wings unavoidably create turbulence and drag, reducing efficiency. One high-lift device employed on the leading edge of aircraft wings is the Krueger Flap.
This aerodynamic profile and its corresponding mechanism, is named after the German engineer Werner Krueger who invented it in The flap hinges down from the underside of the wing when needed to increase the critical angle of attack of the wing. When deployed it increases lift and delays the onset of a stall. The flap is then retracted during cruising flight. One of the advantages of the Krueger flap is that that it leaves the upper wing surface smooth when retracted, and while fully deployed it can protect the wing from insect and dirt accumulation and surface erosions.
Making this assembly as light as possible has obvious advantages in terms of reduced fuel burn, but materials that can lead to more integrated designs also have huge potential. Belgium headquartered Asco is a technology specialist supplying design, development, precision machining, processing and certified assembly of high-lift devices for the aircraft industry. Its customers include most of the major OEMs in the aircraft business alongside tier 1 and tier 2 suppliers.
In recent years the company has been working on its Deamak Project, a programme to design and build a Krueger Flap using composite materials. It is net shaped out of the mould including complex internal cavities. In this process, dry fibre geometries are shaped and inserted into a double-sided closed mould. Once the mould is closed, it is positioned into a press for heating.
The mould cavity is put under vacuum, injected with resin and the fibre-resin composite cured to obtain a one shot complex CFRP component. Moreover, the RTM process has significant automation potential using robots to open and close moulds etc. Additionally in terms of cycle time, manufacturing a composite integrated one-shot Krueger Flap allows a drastic reduction of assembly time compared to a metallic multi-component assembly.Unlike slats or droop flapsthe main wing upper surface and its nose is not changed.
Instead, a portion of the lower wing is rotated out in front of the main wing leading edge. Current Boeing aircraft, and many others, use this design between the fuselage and closest engine, where the wing is thickest. Outboard of the engine, slat flaps are used on the leading edge.
The Boeing also used a mix of inboard Krueger flaps and outboard slats, although it had no engine between them. Most early jet airliners, such as the Boeing and Boeingused Krueger flaps only.
While the aerodynamic effect of Krueger flaps may be similar to that of slats or slots in those cases where there is a gap or slot between the flap trailing edge and wing leading edgethey are deployed differently.
Krueger flaps, hinged at their foremost position that once deployed actually become their trailing edgeshinge forwards from the under surface of the wing, increasing the wing camber and maximum coefficient of lift. Conversely, slats extend forwards from the upper surface of the leading edge. Also, when deployed, Krueger flaps result in a much more pronounced blunt leading edge on the wing, helping to achieve better low-speed handling.
This allows smaller-radius wing leading edges, better optimized for cruise.
The Krueger flaps developed for the Boeing were constructed from fiberglass honeycomb material and were designed to be intentionally distorted into an aerofoil section on deployment. The flap was added to prevent wing stall with an extreme attitude take-off with the tail dragging on the runway, a scenario that had already caused two de Havilland Comet accidents.
A preliminary flight test had been made on the Boeing using a fixed flap and a skid on the after-body. Boeing commenced a series of test flights on 17 March with a modified Boeingincorporating new wing-leading-edge sections and an actively blown vertical tail.
Although Krueger flaps have been tried before as insect-mitigation screens, previous designs caused additional drag; the newer design being tested is variable-camber and designed to retract as seamlessly as possible into the lower wing surface. From Wikipedia, the free encyclopedia. Krueger flap operation. Slat operation.
Bristow Ace the Technical Pilot Interview. McGraw-Hill Professional. Retrieved Lexikon Der Luftfahrt. Aviation Week. Retrieved 23 March Taylor, John W. Aircraft components and systems.