How does an aircraft's wing work?

[Jonzjob]

@mailee:

Not all aeroplanes (airliners) have two ailerons on each wing - please wait until tomorrow's pix (I do hope they haven't moved the A310 overnight)!

And to add to the "mysteries" of roll control, modern aircraft have both Spoilers and Speed Brakes on the upper surfaces of the wings. And in high speed cruise flight the Spoilers often "float" to assist the ailerons with the roll control. "My" Boeing 737 is a typical example (as are all B737s) and you should see the "Heath Robinson" mechanical mixers on the B737 - hiding in the RH Main Landing Gear Bay, which, with a series of "strings, pulleys and bellcranks", "mix" the amount of Spoiler movement of the "real" ailerons according to the speed of the aeroplane). But still, IMHO, it's better than the "plastic fantastic Scarebus" with it's multiude of invisible electrons wizzing silently along bits of wire - can you tell that I'm a mechanical bloke and not an avionics "fairy" at heart can't you?

Perhaps we'll get to gas turbines at a later date (not this trip from me though), although Bernoullui will stand you in good stead understanding those too.

Try that web link I posted yesterday.

Krgds
AES

A, I have just reread this post and realised that you would have LOVED the Britannia and its controll systems.

There were NO power controls on the aircraft. All of the control surface were 'free floating'. When it stood at the end of the runway, waiting for clearence for takeoff the ailerons and elevators were drooped, i.e. hanging fully down, and the rudder was blowing free in the wind! The control surfaces only had any authority when, rudder, 90 knots, elevators and ailerons about 110 knots and then they would come into line. They were totally free to move and the only thing that moved them in flight was a 5 or 6" servo tab along the trailing edge of those control surfaces. The tabs were moved with a series of 6 foot or so 'torque tubes' with universal connectors in line and the servo tubes went from the control coloumb to those control surfaces. The elevators were so sensitive that they had to had a 'feel simulator' to give the driver a sense of how much up/down he was putting in (no females in those daze).

It was a very sucessful system and there were several occasions where our Brits were leaving USAF bases and the tower would send an emergency message to stop the aircraft because the ailerons had failed and were both down! The normal response was "No problem, we have learned to fly with them like that :twisted: :twisted: "

Mailee, if you are worried about jet engines then you will love the `Bristol Proteus" because the air goes in the front, going backwards, then turns through 180º and goes backwards through the 12 stage compressor. Then it turns through another 180º and goes through the cans (the bit where it catches fire!), through the double turbine twin stage turbine and produces about 5,000 lbs thrust.

The double twin stage turbine? The first 2 rows of turbine blades are connected to the compressor and turn the 'jet' bit of the engine. The second 2 rows of turbine blade are connected through the centre of the main engine shaft to the proplellor gear box and turn the 16 foot prop. You with me so far??

The genral outcome is that you have a jet engine that is about the same length as an 'infernal conbustion engine' that runs on rough parafin (carasine (avtur), normal jet fuel) and is much more efficient at medium/ low altitudes than a pure jet 'cause it's got the big windmills on the front.

 

[Jonzjob]

Just found this for any interested parties

http://www.bristolaero.com

 

[newt]

Again lucky enough with my work at Boscombe Down to have flown in the Britannia, we used it as communication aircraft for a long time.

 

[CHJ]

Again lucky enough with my work at Boscombe Down to have flown in the Britannia, we used it as communication aircraft for a long time.

My main hacking was done in the old Devons between establishments usually on a weekly basis, bit unnerving some of the time at the beginning as I was trying to sort out the mod program to upgrade the engines because they were not one engine capable with a full load on board.

Rest of the time flying in such as Vicounts, Varsitys, BAC 1-11 etc. was just work when something needed tweaking in flight.

Once had the pleasure of flying back from Kinloss in one of BD's Hastings sitting on the floor with a load of gear strapped around us, low level down Loch Ness and over to Belfast to drop a boffin off on route. Our Hastings had too much gear installed in fuselage to act as transports.
I think the Beverley that came to collect us and kit from southern Germany in the late 60's also was a BD kite. Created quite a stir when it backed up the taxiway between two hangars for us to load up.
Interesting flying over the Rhine with no back doors fitted looking down at the shipping whilst checking the tethering on the landrover and GPU's etc. stowed on the deck.

 

[newt]

The Varsity had Dutch Roll and trying to have a pee in the toilet at the back end was quite a challenge, some were taken out of service with corrosion at the rear bulkhead. Spent 42 years at Boscombe one of the highlights being involved with the trans Atlantic air race with the 2 Harriers, interesting story to that. Couple of periods in the US during that time. Happy to talk aircraft all day, but I guess to many it would be boring.

 

[CHJ]

Many years ago there was a joke going the rounds about an Aircraft design that kept crashing because the wings broke off.
The answer was apparently supplied by a local building contractor who originated from a little isle off the west coast of England who said they should drill a row of holes across the wing.
When asked what the blazes that would do to improve things he said, “well a bog roll never tears along the dotted line does it”

Ironically within a couple of months we were cutting a 1/8” slot right over the upper wing surface near the root of the wing on the Viscounts to stop the wing flex cracking the pressurised fuselage.

A memory brought back by the flapping wing comment earlier in the thread.


Same problem did not affect the Varsity, although looking an older concept it was actually a newer design than the Viscount and had a more flexible wing/fuselage interface.

 

[Jonzjob]

The Beverley had an interesting situation with the toilets. They were in the very rear of the boom and directly in front of them was the para drop hatch. The paras that were in the boom had a crew member who opened the hatch so they could jump from there without having to go down to the main fuslarge, BUT if you were working on the aircraft on the deck and went into the toilet and someone opened that hatch you wouldn't be the first to go A over T through it and onto the pan below. A few blokes were badly injured by just that. So a mod was introduced that when the hatch was opened it put a pin up so the loo doors couldn't be opened! You had to be very trusting of your mates if you used the loo after that and a favourite was to wait till someone went in, open the hatch and walk away :twisted: :twisted:

I have flown in them but never worked on them..

The nick name for both the Varsity and the Valetta was 'the pig' because that's what they looked like.

You would never have flown in a Belfast with the rear dors open Chas. They were designed for heavy drops and were supposed to be able to take off with a light fuel load and heavy freight load and in flight refuel. When they did the refueling testing at Boscombe Down they found that unless you got the basket first try it hit the bow wave and flicked upwards. Then came back down and smashed into the cockpit roof. Basically the probe was too short and it was as long as it could be made without breaking! So in flight refueling was scrapped. They then went to air dropping and the first time they dropped the rear doors it almost fell out of the sky. It became too unstable to fly! So that was scrapped too. I did have 6 nice comfortable bunks in a nice cabin under the cockpit though so that 2 crews could be carried.

You got it. They took off and could fly around the world non stop with in flight refueling :mrgreen: :mrgreen: Quiet night shifts and I can assure you they were very good!

 

[Benchwayze]

Folks,

Take a sheet of A4 paper by its bottom corners, and let the sheet drape over your hands, away from you.
Keeping hold of the paper, blow gently over the front edge and you will see how/why an aircraft flies.
That's how it was demonstrated to me.


:wink:

 

[CHJ]

Folks,

Take a sheet of A4 paper by its bottom corners, and let the sheet drape over your hands, away from you.
Keeping hold of the paper, blow gently over the front edge and you will see how/why an aircraft flies.
That's how it was demonstrated to me.


:wink:

..............Last but not least, anyone want to try this very simple experiment? Take an ordinary piece of paper (A4 will be fine), hold the paper at the 2 corners of the narrow side. Raise your hands (with the paper) up to your lips (the paper will of course be drooping downwards) and then blow gently over the top surface of the paper. The harder you blow the more the paper will raise up until it's almost sticking out from your mouth horizontally (but still with a curvature ("camber"). And NOT a puff of your blown air went underneath the paper!.....AES

 

[mailee]

Thanks John, but you lost me at the air goes in backwards???? I can get my head around a piston engine but a jet turbine just seems to defy logic! :? Surely it's perpetual motion machine? and where is the starter motor? Somehow it starts and draws air in at the front where it goes through a few fan blades and gets compressed, then fuel is injected and it expands and drives another fan that drives the front fans again ad infinitum!? And how does the throttle work? I tell you it's scary stuff and more like alchemy. :shock:

 

[CHJ]

It's only a few components built around a primus stove on steroids.

It just manages to better the four stroke engine by doing induction, compression, ignition, exhaust all at the same time in a single cylinder.

 

[Jonzjob]

Mailee, it's just a fan assisted blowlamp mate! Nothing complicated, honnest.

The Proteus just reversed the air flow through the 12 stage compressor and then again so that when it went through the cans, the bit that's the blow lamp, the hot gasses were shot out of the back both driving the turbines for the prop gear box and the compressor and then shoving about 5,000 lbs of jet thrust out of the back..

The Proteus wasn't just used on the Britannia. It is still, as far as I know, used on some of the RNs fast patrol boats and there were 4 powering the big cross Channel car carrying hovercraft. Even some in frigates as well. Very versatile bit of kit!

Still just a blowlamp though :mrgreen:

Posts crossed Chas..

Edit : - Nearly forgot.. It also powered the Bluebird to be the worlds fastes wheel driven car and I think that it still holds that record. Pure jet 'projectiles' have gone faster but the are just blown along and not driven by the wheels ..

 

[Peter T]

Thanks John, but you lost me at the air goes in backwards???? I can get my head around a piston engine but a jet turbine just seems to defy logic! :? Surely it's perpetual motion machine? and where is the starter motor? Somehow it starts and draws air in at the front where it goes through a few fan blades and gets compressed, then fuel is injected and it expands and drives another fan that drives the front fans again ad infinitum!? And how does the throttle work? I tell you it's scary stuff and more like alchemy. :shock:

If you're having problems with that, you might want to consider something else.

In the hot parts of the engine, the combustor and the first stage turbine, the temperature of the combustion gasses passing through is typically 200 to 300 degrees C higher than the melting temperature of the metals that the engine is made of!

To prevent catastrophic meltdown, the components are peppered with thousands of small cooling holes through which "cool" air is fed to provide a laminar flow of cool air to protect the metals. This, in conjunction with high temperature ceramic coatings, prevent anything nasty happening!!

 

[mailee]

I do know about the heat inside one of those and the ceramic coating and drilling due to being an avid watcher of the discovery channel. i was engrossed in the documentary about building the Rolls Royce Trent engine but still find it hard to understand how it actually works! i think a fan assisted blow lamp is understating it a bit though. :lol: I take it that the reverse flow engine is the same design as the Frank Whittle original as that seemed to have 'cans' surrounding the engine? But how is a jet turbine started and why doesn't the starter get melted? I also assume the throttle works by injecting more fuel into the combustion chamber? Also the combustion chamber is open to the elements with only fans separating it from the outside? I assume it can't escape to the front due to the incoming air so escapes to the rear driving the fan. Got to admit it's a damn expensive blow lamp. :lol: Thanks for the info guys it is certainly an interesting thread.

 

[CHJ]

The starter motors are outside the main engine system.
Either a powered turbine on the front as in the cartridge powered RR Avons or via a side mounted gearbox via a bevel gear off the main compressor shaft.
Just as you take off power for generators/alternator, hydraulic pumps cabin pressure compressors etc. you can induce power the other way with a starter motor.

 

[Benchwayze]

Seems my post was redundant.
I'll just learn to read the threads more thoroughly I guess!
So much for speed-reading. That's another book I think I will throw away.

MAILEE,

I know this is a change of thread, but just to give you something else to think about...


How does a torpedo internal combustion engine operate underwater? :lol: :lol: :lol:

 

[Jonzjob]

Read this M and you'll be as wise as me http://www.leitemlane.com/jetoperation.htm

Mind you, that ain't difficult, but I'm quite cleaver when I get me brain cell wound up :? :?

You can see why they are called cans too!

 

[Jonzjob]

John, your post wasn't redundant at all!! And yes the acceleration is done by throwing more fuel at it and if you really want to make it look like a blow lamp then you can inject even more fuel into the jet pipe, the tube after the turbine blades and immediately before the end of the engine. It then ignites and gives anything up to about 40% more grunt and big butch flames out of the back! That's why Concord was a bit noisy on takeoff..

Torpedoes. Their infernal combustion engines use the same type of fuel as rockets and Avpin. A mono-fuel that makes its own oxygen. Others use electric motors.. One type the Germans used in WW2 was a seeking type and if it missed the target on the way through it would turn and find a target. Sometimes it found the sub that fired it (hammer) (hammer) :mrgreen:

 

[Jonzjob]

The 'V' bombers were air started and all 4 donks could be started at once. You also have the Avpin starter too. That uses a mono-fuel, Iso propyl nitrate, It makes it's own oxygen. This is quite an amusing story about it http://rhodesianforces.org/No1sqnavpin.html

Also used on Lightenings and some marks of Canberras :shock: :shock:

Edit : - Avpin was also used on the later marks of the 'Grovellin', or Javilin as it was offically called. Here is an excerpt from a Javilin web site about both the cartridge start and the Avpin jobs. As a matter of interest, the Jav driver and nav didn't strap themselves in untill both engines were started and as there were a Javilin squadron just uo the flight line from 81 Sqdn PR7 Canberrers at Tengah, Singapore when I was on 81, the next time I see a nav legging it down the wing and off the tip when one caught fire will not be the first time :shock: He ran down the wing because if he climbed down the steps he was directly in frond of the eng intake and had to run across the front of the missiles as well !!!

SAC Terry Jones has kindly sent me this description from when he worked as a member of a Javelin ground crew:

"I served with No 1 GWTS at RAF Valley in 59-61. We had six Javelins with Firestreaks doing the missile trials. The cartridges they used were about 1.5" dia 6-7" long. Black Plastic bodies and the breech took three. 'WET' starts, when the thing did not fire up on the first or second shot, were always an exhilarating sight, with many yards of flame from the tail pipe. Incidentally, I have had many a meat pie from the NAAFI wagon re-heated in the tail pipe after a sortie!"

Allen Mawby remembers the AVPIN starter:

"[...] the Mk 7 and 9 used AVPIN start. A small cartridge similar in size to a 12 bore pressurised and ignited the highly volatile Avpin which powered a small turbine which in turn started the engine.

This system was truly bad as the Avpin often either exploded the high pressure pipe lines, which ran through the main electrical and hydraulic bay in the underside or caused the turbine to overspeed, shed all its small blades through the engine intake which normally resulted in an engine change.

If the pipe lines exploded the wings were removed and the remainder was sent to be rebuilt!

I cannot remember a black powder cartridge start system ever causing damage. Avpin starts caused immense damage."

Mike Guy remembers similar problems:

"[...]later marks of Javelins were fitted with 'AVPIN' starters. Avpin was a very volatile fuel and the starter plumbing supplying the Avpin to the starter was prone to leaks.
As I remember fires during start up were not too uncommon & it wasn't unusual to see a ground crew member "legging" it across the tarmac closely followed by the flight crew."

 

[Jonzjob]

Just found this youtube. This shows a centrifugal compressor, the early type of engine as used by Meteors, Vampires, Venoms, etc.

http://www.youtube.com/watch?v=MUxP3PCDRTE&feature=fvwp

Not brilliant but this is a more modern engine with a multi stage linear compressor

http://www.youtube.com/watch?feature=en ... o8e6L3JTMQ

And this is a bypass turbine engine

http://www.youtube.com/watch?v=ON0sVe1y ... re=related

Good ere init!!