Thesis Flaps & Slats

[Quinten A]

Dear reader,

I'm in my last year of secondary education, and must make a thesis which I do with 2 other students.

Our subject: flaps and slats.

Our goal is to create a complete theoretical book about flaps and slats to deal with it both technical (operation, construction, etc...) and general (history, physical and aerodynamic aspects, etc...) information.

We want to show the difference of how a technician looks to flaps and slats and how a pilot looks to flaps and slats and want to bring that together.

Also problems must be discussed (eg what if the left inboard flaps do not work, etc...): the consequences for the pilot, how the technician solves it, etc...

So basically everything what you can say about flaps and slats...

My question now is whether any of you has any special & other ideas, can help us to find information (pictures are welcome), etc... That would really be great.

Thanks for your help :ok:

Best regards,
Quinten

(Sorry for my English spelling.... My language of origine is not English)

[Genghis the Engineer]

Please don't get carried away - there is much more material on this topic than you can possibly use.

There are numerous texts for pilot training which explain their use - just search on Amazon for them (then borrow them from the library). The material for private pilots is usually simpler than that for professional pilots.

The industry standard data sheets on the aerodynamic effects of slats and flaps are those published in the UK by "ESDU", the Engineering Sciences Data Unit. To obtain those, you're likely to either have to pay, or to get them through your local university library - if that university offers engineering anyhow.

There are several good aircraft design textbooks which will cover the topic; I suggest as (relatively) easy using Darrol Stinton's "Design of the Aeroplane", which is widely available and very well written.

A lot of historical technical material can be downloaded for free from the NACA reports server (http://naca.central.cranfield.ac.uk/)- here's one to get you started. (http://naca.central.cranfield.ac.uk/reports/1933/naca-tn-475.pdf).


Very best of luck,

G

[Quinten A]

Hello Genghis,

Thank you very much for your information.

Thanks for your book suggestion, and that NACA reports server seems to be very detailed and helpful to browse in history.

Thanks again,
Quinten

[Mad (Flt) Scientist]

I'll agree with Ghengis that is one huge topic. I fear you may swamp yourselves.

Personally, I'd suggest you don't do the specific things like failure cases and troubleshooting because that is extremely dependent on the aircraft. Unless that is the required topic, in which case you should focus just on that, for selected types, and not try to cover everything.

My suggestion would be to focus on the history of the development of flaps and slats - the different types, and why each was introduced. That allows you to, at each stage a new idea came along to explain why it did so, which allows you to then address the aerodynamic or structural aspects as they are relevant.

Otherwise what you are proposing is very ambitious and, I fear, may be unachieveable for you.

[Quinten A]

Well, our mentors expect us to also do specific things, but this for the Airbus A319. We work together with Brussels Airlines (they have A319's in their fleet) + because we thought to work from past to present. And the A319 is one of the most newest aircraft with most advanced flap system.

Best Regards,
Quinten

[EW73]

By way of comparison, you might want to look at one of the early complex flap systems.

That would be the DeHaviland Caribou aircraft, with both flaps and flaperons, as well as a pitch change input into the horizontal stabilizer with full flap.

Interesting system...

EW73 :)

[Slasher]

...basically everything what you can say about flaps and slats

Should I post this on PDRuNe? -

Hello doctors I am an airplane pilot about to do a thesis on
heart operations. Please tell me basically everything what
you can say about open heart surgery.
Thank you.

[Dual ground]

Well, our mentors expect us to also do specific things, but this for the Airbus A319. We work together with Brussels Airlines (they have A319's in their fleet) + because we thought to work from past to present. And the A319 is one of the most newest aircraft with most advanced flap system.

Best Regards,
Quinten

Actually I would have thought that the 747 flap system was more complex, aerodynamically speaking, than the the A320 family. Krueger flaps, variable camber leading flaps and triple slotted trailing edge flaps.

[Genghis the Engineer]

Should I post this on PDRuNe? -

Hello doctors I am an airplane pilot about to do a thesis on
heart operations. Please tell me basically everything what
you can say about open heart surgery.
Thank you.

Personally, I welcome a few students on here - where (as has been the case here) they've been polite and asked sensible questions, it might bring some bright young people into aviation careers, and gives the rest of us an excuse to look clever! For somebody still at school, it's really not possible to see the complexity in the question that we do.

G

[ChristiaanJ]

Genghis,
Thanks for giving Slasher a polite answer...
I would have given a much nastier reply to such a rude post addressed to a serious 16-year old, who's already found his way here.
I envy him... at his age I didn't get that kind of assignments. Just drew aircraft designs in the margins of my Latin note books....

Quinten,
I would agree with earlier posts... don't overload with 'facts', just develop the basics.

Theory : why flaps and slats? how do they work aerodynamically?

Practice : briefly go from the simplest flaps to the most complex.
Include a mention of extremes such as the blown flaps on the F-104, or on various STOL aicraft.
Then elaborate on the A320 family slats/flaps, and maybe compare with the B737 (where indeed during the landing just about the whole wing droops down one way or another, leaving just about only the wing spar in place :) ).

Engineering : all the way from the simplest hinged flaps to the complex actuators, screw jacks and flap tracks/rails needed to make the basic idea of, for instance, a split or Fowler flap, work in real life.

Maintenance and troubleshooting : Unless your mentor insists on this, try to keep this short, because flaps/slats are not really all that different, in that respect, from most other aircraft systems, whether mechanical, electrical or hydraulic.

Quinten, you'll have to do your own research. But I think you'll find there are a few oldies here that are perfectly willing to help out when you get stuck.

Christian

PS : Don't worry about your English, you're doing fine.

[Prober]

Quinten A, I admire your enquiring mind. I spent many wonderful hours flying the Trident (HS25) which had a very good example of Leading Edge 'lift enhancement', otherwise known as the Droop. I am not of a theoretical turn of mind, unlike the admirable M(Flt)S or Genghis, but I would commend something quite different to your attention. Have you ever plucked a chicken? If so, you will be aware of the strange lumps on the front (leading edge) of the wings. These are muscles and there is, somewhere, a marvellous film of pigeons landing and demonstrating that these muscles are, in fact, leading edge droop. The pigeons extend them a fraction of a second before landing, thus delaying the stall until required. It is absolutely fascinating and I have often wondered whether the designers of the system were aware that they were, in fact, copying something already designed by 'mother nature' long before man ever even dreamed of flying. I am sure that an inclusion of this fact would add an extra - and possibly unexpected - dimension to your thesis. Good luck.
Prober

[HarryMann]

OK, start with some basic facts separating l.e. slats with t.e. flaps

L.E Slats: Extend the angle of attack range of the wing (^ the stalling alpha)

T.E. Flaps: Give a step (Delta) increase in Lift Coefficient by increasing camber

[Quinten A]

Hello all,

Sorry for my later reply. Busy these days.

Thank you all for your information, tips and ideas. Very helpful.:ok:

For slasher: during my research, I also found information about that kind of flaps. But since I thought to post my question on a 'Professional Pilots Rumour Network' forum, I thought I would not get any reply with information about that .....

Again, thank you all, and I will maybe later post some questions, where we possible can't find an answer for.

Thanks,
Quinten

[Genghis the Engineer]

Have you ever plucked a chicken? If so, you will be aware of the strange lumps on the front (leading edge) of the wings. These are muscles and there is, somewhere, a marvellous film of pigeons landing and demonstrating that these muscles are, in fact, leading edge droop. The pigeons extend them a fraction of a second before landing, thus delaying the stall until required. It is absolutely fascinating and I have often wondered whether the designers of the system were aware that they were, in fact, copying something already designed by 'mother nature' long before man ever even dreamed of flying. I am sure that an inclusion of this fact would add an extra - and possibly unexpected - dimension to your thesis. Good luck.
Prober


I have on my desk the latest issue of Aeronautical Journal (November 2010), between pages 673-680 is a fascinating paper entitled "Mechanics and Aerodynamics of perching manoeuvres in a large bird of prey". The maths is rather beyond school level, but there are some fascinating pictures showing the shape of the wing and how it changes shape in flight and landing. You can buy copies of those papers for download here (http://www.aerosociety.com/raes_old/journals/journals.asp), although I notice that the November issue isn't up yet.

G

[bearfoil]

Your Prof has seen it all, so I would try something different. Each of you three take a position, Engineer, (design, aero,etc.), Pilot, (performance, systems, training), and the Operator (risk/benefit, ROI, cost of acquisition and maintenance, etc.). Select a well proven type, whose systems exemplify the goals of "wing creation" on demand, and give it a snappy Treatise/ Title:

'The 727: From Bug-Smasher to Boom, and Back'.

welcome, and best of luck!!

bear

[Pugilistic Animus]

Quinten A

indeed a complex topic--- really I hope you'll realize in your basic reasearch the whole thing is really an art... [even if you were a math genius] it would really be too hard a subject to go into further detail...but I hope you can see after your study for the project that these things are more than simple devices they are true artwork---sometimes a fact lost to the people :{

Good Luck:)
rcqoB_QICxA

[ChristiaanJ]

Genghis,
A bit outside Quinten's subject and field, but it's worth looking at a birds feathers on its "hands", the alulae and primaries.

http://www.infovisual.info/02/img_en/057%20Wing%20of%20a%20bird.jpg

Somehow, I've never seen any aircraft design use small outboard leading edge slats for roll control similar to the alulae.

Weirdly, I can imagine immediately spreading my arms to soar and then "twitch" my thumbs (the alulae) to maintain steady flight, and spread one hand downward to sharply turn into a bank...

CJ

[Prober]

Well, Well Well!!!
Many hours did I spend in "The Gripper" (HS25 for the uninitiated) and the control column was in the shape of a ram's horn. For delicate flying, a roll would be executed by a gentle pressure of the thumb on the side of the horn. Just what ChristiaanJ has envisaged!
Prober

[John Farley]

It may seem that your topic is specific and focused so capable of a fairly simple factual answer.

In fact flaps and slats are an important PART of an aircraft design and as such are affected by other parts so the simple facts about them will probably only be 90% of the story the last 10% involving many other factors of the aircraft.

Whenever you are thinking about any aircraft (or feature of that aircraft) you must constantly tell yourself that all flying is about two things:

Lift (and having enough to cope with the weight)

Control (if you cannot easily and reliably control both the amount of lift and the direction it is acting you do not have a safe aircraft)

Your topic involves mainly the provision of lift but also will affect control (especially when flying close to or in a stall)

As a SIMPLE example of the constant interaction of all the factors of an aircraft's design consider that if you are running out of ideas about how to get more lift you could tackle your problem by using a lighter structure and reducing weight. Similarly if your aircraft is not strong enough you may have to increase weight which will mean you have to find more lift.

[Genghis the Engineer]

Somehow, I've never seen any aircraft design use small outboard leading edge slats for roll control similar to the alulae

The British Noble-Hardman Snowbird does.

G

[ChristiaanJ]

The British Noble-Hardman Snowbird does.Never heard of it, so I did a quick read.
Seems it has "spoilerons", i.e. outboard spoilers used as ailerons.

I thought the alulae worked differently, but I'd better read up again on bird flight (and bird flight control) before spouting rubbish !

CJ

[bearfoil]

Don't the alulae work as a pivot point for wing "crank", as birds "fold" in their wings to change Lift directly to drag, and facilitate, a hover/perch? I have always watched birds in this way, as they scream toward a fence, and at the last moment, raise AoA to the vertical, and slow precisely above their "landing spot"? The alulae would allow top surface laminar flow, to hide the front spar's glove joint from the airstream, no? The most interesting are Geese, as we have a large Pond, and they are gathering for the next leg of their Southward trek. They do exquisite "straight-ins" seemingly on a rail, with a touchdown and "rollout" that is the envy of any flyperson. They also can perform a hook to final that leaves them motionless six inches above the water, to allow gravity to complete their "alight" on the surface.

bear. We have alot to learn, and admire, in the Aves portion of our World.

[MISSED APCH]

http://upload.wikimedia.org/math/a/0/4/a04312bd12e12a54187692bc2cc91952.png

start here[1] (http://en.wikipedia.org/wiki/Flap_(aircraft))[2] (http://en.wikipedia.org/wiki/High-lift_device)[3] (http://en.wikipedia.org/wiki/Flight_control_surfaces) and build from there!

once you have some text in place, i'd be more then happy to receive your text and elaborate.
i suppose you would like to go even deeper in it, but i dont know till what extend. you let me know.
think i did give you 50% of it already.

from a pilots perspective...
what ive learned back in school, proves in practice to be only half the truth about flaps. we use then mostly as BRAKES while not outside limits.:ugh:

well good luck then !

[d105]

Quinten,

There's two general publications that will help you out quite a bit.

1. Oxford ATPL training - General principles of flight.
2. RAF - Royal Air Force - Principles of flight manual.

I've got hardcopies of both and a scanned pdf version as well. If you like, I can upload those for you. Give me a PM for details.

[Genghis the Engineer]

Never heard of it, so I did a quick read.
Seems it has "spoilerons", i.e. outboard spoilers used as ailerons.

I thought the alulae worked differently, but I'd better read up again on bird flight (and bird flight control) before spouting rubbish !

CJ

The spoilers are fairly small and located about 50% chord and about 2/3 span. They work rather well - good roll control without any adverse (or proverse) yaw - although because of the lack of any need for rudder in airborne flight the designers didn't put much rudder on it, making it fairly useless in crosswinds.

Superficially similar to alulae. Possibly.

G

[Prober]

Ref Missed Apch post #23.
I remember many years ago we DID indeed frequently use flaps as brakes, but with the advent of larger aircraft with greater wingspan and consequently more complex flap mechanisms this is no longer the case. I recall one well known aircraft manufacturer sending out a letter asking us to treat the mechanism with respect because of this complexity, telling us that they were strong enough, but continued such use would put unnecessary strain on the works.
Indeed, small amounts of flap can tend to make the aircraft more ‘slippery’, quite the opposite of braking, and it is not until one has greater than T/O flap that major drag comes into play.
Prober