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question for Scutter
stephen_gusterson - 12/12/02 at 11:55 PM

Hi

I am pretty sure you are the aircraft tech?

I mentioned to my 14 year old son that a car ideally has a 'swirl pot' to hold fuel so that the car doesnt get fuel starvation when cornering.

Over the months, he keeps asking me to ask you how the heck does a fighter jet get its fuel - what with the G forces and attitudes the plane can take.


Any ideas (not that Im gonna build a Tornado just yet
)


atb


steve


scutter - 13/12/02 at 06:21 PM

The aircraft also have swirl pots just like car but they tend to hold around 50 gallons each and are backed up by air pressure that forces the fuel into these swirl pots(collector tanks on an aircraft).

Hope this helps with the questioning

Take care Dan.


stephen_gusterson - 13/12/02 at 07:59 PM

Thanks fror the answer!

So I suppose if you fly upside down too long, you might have a problem!

atb

Steve


scutter - 13/12/02 at 09:00 PM

Yes the bombs never fall off the wings, also you get sick(well I do)

Take care Dan.


scutter - 14/12/02 at 09:51 PM

proper job J/T propulsion tech, working at Boscombe Down.

Avatar pic of boss and co, Breaking things as normal.

take care Dan.


James - 16/12/02 at 06:39 PM

quote:
Originally posted by scutter
proper job J/T propulsion tech, working at Boscombe Down.

Avatar pic of boss and co, Breaking things as normal.

take care Dan.


Would I be right in thinking that you can't sign up after 25?
Only reason I ask is that since last Farnborough airshow I've wanted to be a Eurofighter pilot ever since.

Cheers,

James


stephen_gusterson - 16/12/02 at 08:39 PM

is 25 meaning years or pints?


atb


steve


geoff shep - 16/12/02 at 09:14 PM

James, max at the moment for pilot is 23.

Steve, here's a bit of swirl pot action,

(thanks scutter, editted my previous post and deleted it)

[Edited on 16/12/02 by geoff shep] Rescued attachment upside down.jpg
Rescued attachment upside down.jpg


scutter - 16/12/02 at 10:24 PM

yeap that would make me sick

We've got one of the "ton" in the hanger at the moment.

All the best Dan.


stephen_gusterson - 16/12/02 at 11:00 PM

Ah ha!

Now, that pic prompts a question I have always wondered about :

If the shape of an aircraft wing creates lift, why doesnt a plane lose lift when the wing is upside down - ie reversed profile?

Is it just a matter of somehow 'trimming' the wind leading / trailing edges to compensate? I could ask my C130 pilot realtion next time I see him, but I doubt he flies hercs upside down that often




atb


Steve


chrisg - 16/12/02 at 11:06 PM

Geoff,

Thats a nice hairyplane, what is it, and do they cost more in black, like cars?

Cheers

Chris


David Jenkins - 17/12/02 at 08:48 AM

quote:
Originally posted by stephen_gusterson
Ah ha!

Now, that pic prompts a question I have always wondered about :

If the shape of an aircraft wing creates lift, why doesnt a plane lose lift when the wing is upside down - ie reversed profile?



Steve,

The cross-section of most fast wings is nearly symmetrical - in fact, it doesn't have much cross-section at all on a fast jet!

When it's upside-down the plane has to fly with its nose pointing up more than usual (that's 'up' in relation to the ground, not the pilot's 'up' ), but there's still enough aerofoil to keep it flying.

It's not as efficient as right-side up, but it works on a fast plane. On a slow plane (e.g. a trainer glider) the aerofoil shape is thick and flat-bottomed, and therefore hardly capable of inverted flight (it's usually forbidden).

David
(Guess who used to fly fast R/C slope-soaring gliders... but no longer... no slopes in East Anglia!)


jollygreengiant - 17/12/02 at 09:28 AM

Chris
it a hawk trainer similar to those used by the Reds Arrows (if Im right the black colour is used by the training flight out in Wales, St Athan is it? I forget the Sqn No)


David

Almost right.

Wings provide lift by virtue of speeding up the airflow over "the top" to create a relative drop in pressure compared to the underside which over the entire wing creates lift. Generally the thicker the wing the higher the lift generated and a flat underside generates more lift relatively. Military aerofoils Tend to be Laminar flow with similar profiles above & below the centre cord of the wing. Lift is Generated by increasing slightly the angle of attack of the wing & by higher speed of the aircraft.
Inverted flight is maintained by pushing the nose of the aircraft upwards (stick away from you) so that you present the top of the wing (normally) to the oncoming airflow and the limited turbullence this then creates past the leading edge & over the underside (normally) speeds up the airflow creating lift to the underside of the wing. most aircraft will fly inverted quite comforably the limiting factor is usually the -G that the wing will take which is why most helicopters cannot do a loop, beacuse there rotor will not take the -G stress's involved. Of Normal aircraft Aerobatics are usually ok only limited by the spin characteristics which is a whole different ball game (& theres quite a few military jets Costing millions that you just DON'T Spin cos they bite back)


Sorry but aerodynamics is quite long winded.


geoff shep - 17/12/02 at 09:37 AM

Well, how long have you got?

Lets say the wing needs to be at, say, 2 degrees nose-up to produce enough lift to maintain level flight at cruise speed. It makes sense to bolt the wing on at 2 degrees to the fuselage so that the fuselage flies level - to minimise drag etc.

Assuming the wing is as efficient upside down, then to fly level upside down the wing still needs to be at 2 degrees nose-up which is 4 degrees for the fuselage. Actually, its not as efficient, as DJ says, so you might need 5 or 6 deg nose-up upside down.

So it's more to do with angle than shape, like the wings on the back of your F1 car. Vary the angle - vary the downforce. If they varied them all the way to nose-up the car would lift off.

Chris, it's a Hawk. You can have any colour, so long as it's black - unless your a Red Arrow in which case it's red! All training aircraft are (or are being) painted black because it makes them easier to see.

Rescued attachment flight.jpg
Rescued attachment flight.jpg


James - 17/12/02 at 09:48 AM

quote:
Originally posted by geoff shep
James, max at the moment for pilot is 23.
[Edited on 16/12/02 by geoff shep]


Doh!
Oh well, that's that plan out the window- I'm 25 in April! Thought I had a few months to decide!


James

....Can you change your D.o.B by deed poll?

[Edited on 17/12/02 by James]


bob - 17/12/02 at 01:03 PM

James

Plenty of time for you to go commercial,think of the benefits of overnights and hosties

[Edited on 17/12/02 by bob]


Simon - 17/12/02 at 05:21 PM

Guys,

If any of you want to learn to fly - get into a weightshift microlight. VERY Cheap way to get in the air.

The RAF gents will no doubt tell you how good it is to fly at 500 mph at 300 feet.

I suggest you try 60mph at 7 feet - much more fun.

Even hedges and gates become a challenge, let alone the trees:-)

Don't get me wrong - love to have a go in something that climbs at 5 miles a minute.

Most fun ever had in a plane was a YAK52.

ATB

Simon


scutter - 17/12/02 at 06:10 PM

Don't let the fast jet boys fool you into thinking that they don't go any lower than 300'.

Had a Tornado at west freugh in scotland nearly take my head off

But then he was doing a JP233 practice run(I'll let you all find out for yourselfs what a JP233 does).

Glad you lot answered the aerodymanics question, All I do is make sure that the engines work, if those aerofoils go upside down then something has definatley gone wrong.

The hawk is a 100Sqn jet out of RAF Leeming.(up north)

ATB Dan.

[Edited on 17/12/02 by scutter]


David Jenkins - 17/12/02 at 06:44 PM

My most notable experience was in North Wales, while driving along a valley. It was a typical welsh valley road - just above the lowest part, to keep out of the river.

As I was going along one of my kids said "look at that plane!" - looked horizontally through the hedge, to see an A10 passing us by at equal altitude (about 25 metres above the river!). Shortly followed by his partner only just a little higher up (they went around in pairs).

They then zoomed up to a col and did that 'flip over and pull back' manouevre to get over the hill top without blacking out.

Impressive!

David


bob - 17/12/02 at 06:49 PM

but there's no hosties on microlights

[Edited on 17/12/02 by bob]


Simon - 18/12/02 at 12:14 PM

Dan,

Wouldn't have something to do with runway denial, would it?

ATB

Simon


scutter - 18/12/02 at 01:09 PM

Yeap, now banned because it used to spit out over 200 mines,

Bloody great thing, you could just about squeeze two under a tornado.

Take care Dan.


Simon - 18/12/02 at 05:19 PM

Have to use a Daisycutter instead. I guess that would make one great big hole, rather than lots of little ones!!

ATB

Simon


scutter - 18/12/02 at 05:36 PM

Now that's a great idea, a bomb that can only be dropped by a transporter.

Shame we don't have any, would be fun to try and strap it under a harrier.

Dan.