'Tis The Season

[Renegadenemo]

Yes, it's been fun, but where are all those people who've signed up of late but haven't posted yet? Come on, we know you're there, we don't bite...

[kneeslider]

Hi there, and a merry Christmas to one and all! Been lurking aound here since the inception of the forums, but haven't registered until now, so I guess it's long overdue that I had a go at posting.

I'm especially looking forward to all of the tedious nitty gritty which is to come when you start getting K7's systems back together and all working in harmony, that is going to be when it stops being a chuffin great ornament, and starts being a living, breathing (and scary!) thing once more! Maybe I might just learn a little more about how you get a tune out of a jet engine on the way.

[Renegadenemo]

Hi there... getting a tune out of a jet engine is a proper vertical learning curve. At least the way we're doing it is! We've recovered and stripped K7's original fuel system then had a major aerospace company take a look at it. I's rebuildable but what a complicated piece of kit. Fear not - everyone will get to learn about 1960's jet engine technology before we're done. Incidentally, when trying to identify what components were in K7's fuel system we discovered that it included an experimental unit sent to Bristol Siddeley in 1959 to control a surge problem on the early Orpheus. Only two were ever built and we now have the only one in the world...

[kneeslider]

Cheers for the reply Bill, I guess that for me the most interesting part of the whole enterprise is the part where you actually make it all work, unlike, as you suggested the bit where you put the outer skins on and make it look like a boat again. If that is all people care about, then you may as well have built a replica for the HLF! The making it work part is always the tough bit, after all, anyone can spanner something together, but the subtlety is how you spanner it together.

Any chance of some sort of schematic of how all the oily bits are connected together?

[Renegadenemo]

Oily bits... how dare you, sir! You'll be able to eat your dinner off our fuel system when it's done.

I'll gladly supply a schematic once I get my head around the bloody thing myself.

Basically the engine pump shoves fuel into a gubbins called a CCU or Combined Control Unit that delivers a constant flow to all seven burners to keep the fire alight. Then it has a second circuit that feeds the burners separately for throttling up and down. But the CCU has a thingmabob on the side of it called a BPC or Barometric Pressure Control to mess with the fuel pressure depending on some engine air pressure parameter or other. Not figured that bit out yet. And then the whole lot is watched over by another widget called a AFRC or Air Fuel Ratio Controller that's also full of valves, pistons, springs and barometric capsules.
The entire system self-governs using a servo in the engine pump to increase or decrease the stroke of the pump pistons. servo pressure is the lifeblood of the system and our pump uses an old and imprecise method of governing itself compared to later pumps.
Think about it... you can't just chuck more fuel on the fire when you want your engine to go faster or all that'll happen is the pressure in the hot end will overcome the compressor and vomit fire out the mouth of the engine so you have to bring it on in a controlled manner. Likewise, when you lift off, there's loads of compressed air heading backwards that'll blow the fire out if you're not careful but you still want to be rid of excess thrust in a hurry for carrier landings and such.
It's all done mechanically on the Orph and it's well tricky. Fortunately we're in good hands with this stuff...

And don't get me on topic about those terminal fools at the HLF. They were never going to get a facsimile of a boat out of us lads! I remember one day saying that if we were going to put an airspeed indicator in the cockpit what was our excuse for not plumbing it in. Not value for money, they told me, so I offered to do it free and on my own time. That stumped them completely - idiots.

[kneeslider]

Great info! I have no doubt whatsoever that by the time you lot get finished, you could eat any ammount of dinners off any surface of the boat if you are nuts enough!

Having never messed with a jet engine, now you come to mention all that stuff, it seems so clear! Of course you would need an automatic mechanical correction device to keep the engine running at it's optimum stochiometric ratio, no matter what the outside air temps and pressures are, and then you would need something else to govern the rate at which fuel enters the engine as spools up and down. The great thing is, that with this sort of '50s technology it's all 'real' you know, not a microprocessor in sight!

Sounds like it was all designed by the same bloke who thought of Lucas mechanical fuel injection on my old car...

And before you ask, I am taking an interest in all this stuff, in spite of being under 40, just!

[Renegadenemo]

Turbojets don't run a stoichiometric mix, they throw a shedload of excess air through the fan, which is why you can stick an afterburner on the back and burn even more fuel...

[Piston Broke]

and barely a cross word.

Here's one

crossword_400_400x400.jpg

1 alcohol suppresses this (8)
7 alcohol’s quality leading to many toilet trips! (8)
8 device transporting beer to the glass (4)
10 dram of liquor (3)
11 old measure of percentage alcohol (5)
12 single whisky & half a Heineken are this in terms of alcohol (5)
15 18th century, aniseed flavoured liqueur (8)
18 type of vision induced by alcohol (6)
20 alcohol’s chemical identity (7)
22 measure device (5)
24 women have less – hence the guidelines are lower (5)
26 vertically challenged spirit (5)
27 cider fruit (5)

DOWN

2 this noun classifies alcohol as toxic (6)
3 what’s your - - - - - - ? (6)
4 only this sobers us up (4)
5 purify liquid (6)
6 it is because alcohol is this that body function slows (10)
9 strong dark beer (5)
13 number of units in a pint of Stella (5)
14 where wine is kept (6)
16 only safe number of units before driving (4)
17 drinking salutation (6)
19 useful measurement of alcohol (4)
21 clear spirit (5)
23 alcohol-free days recommended per week (3)
25 lager - - - (3)

[captainbear]

It was EIGHT o’clock and TIME for a TIPPLE, so I went down to the CELLAR to DISTIL a UNIT or TWO of APPLE VODKA. I went through a SHORT TUNNEL and back up TOP, looking for PROOF of the DIURETIC quality of a TOT of ABSINTHE in my WATER, but there was NONE. I used a STOUT PUMP on the ETHANOL OPTIC, but found that THREE sips of the POISON was a DEPRESSANT, and killed my APPETITE.

CHEERS!

[Renegadenemo]

It's the answers to the crossword...