Hi, going off the current topic and trying to understand these jets a little better : I've done some homework and read that the boat uses a total loss battery system ad the alternator has been removed. Ok, I get that for things like ignition systems,fuel pumps and for control. Does it provide power for the hydraulic and lubrication pumps too? There's some fairly hefty looking pumps etc including a gearbox (I read) under the tinware & can imagine they have quite demanding power requirements, I'd be quite impressed if that's all running from the batteries. Or is there another way, like a hydraulic pump driven off the main shaft that does all the extra work? I can''t see one mentioned.
(I suppose an alternator would have once been in the nose cone near the air start at one point).
Technical Talk
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Blackplate
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Renegadenemo
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Re: Technical Talk
The aircraft uses a DC generator driven from the engine gearbox as is the hyd pump. The electrical system on the boat only powers the boost pumps and igniters so for the shore durations expected on record runs it's more than adequate.
I'm only a plumber from Cannock...
"As to reward, my profession is its own reward;" Sherlock Holmes.
'It ain't what they call you, it's what you answer to.' W.C. Fields.
"As to reward, my profession is its own reward;" Sherlock Holmes.
'It ain't what they call you, it's what you answer to.' W.C. Fields.
Re: Technical Talk
The on board batteries are 75 Ah rated and in theory could power the boat continuously for around 5 hours at full load. As Bill says, more than enough capacity for short record runs.Renegadenemo wrote:The aircraft uses a DC generator driven from the engine gearbox as is the hyd pump. The electrical system on the boat only powers the boost pumps and igniters so for the shore durations expected on record runs it's more than adequate.
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Blackplate
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Re: Technical Talk
Ok thanks, that helps. Hope this doesn't sound too dumb though but I can't find a definitive ; Where's the engine gearbox drive from? I can imagine something like a planetary set under the nose but a geared running-ring off the rotors with a hole in the pipe for a primary gear to is a mind boggling thought. Cheers all.. Bp.
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Renegadenemo
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Re: Technical Talk
Where the start turbine plugs into the nose of the main shaft, under the inlet bullet, there's a bevel gear driving a vertical shaft that goes down into the gearbox at the front and below the engine. The gearbox then drives the main fuel pump, the hyd pump and a generator, though we don't use the generator.Ok thanks, that helps. Hope this doesn't sound too dumb though but I can't find a definitive ; Where's the engine gearbox drive from? I can imagine something like a planetary set under the nose but a geared running-ring off the rotors with a hole in the pipe for a primary gear to is a mind boggling thought. Cheers all.. Bp.
It also drives the main lubricating and scavenge pumps bolted to the outside of the gearbox and fed via those stainless pipes from the tank up top (one pressure and two scavenge stages in there). There's an additional scavenge pump inside the gearbox. There's also a metering pump that drip-feeds oil to the various bearings and gears including the rear turbine bearing where it's burned off.
The bearings, etc all have two oil pathways and the metering pump will send oil down them alternately so if one becomes blocked the other will still lubricate the relevant gear or whatever, but there's only one feed to the rear bearing.
I'm only a plumber from Cannock...
"As to reward, my profession is its own reward;" Sherlock Holmes.
'It ain't what they call you, it's what you answer to.' W.C. Fields.
"As to reward, my profession is its own reward;" Sherlock Holmes.
'It ain't what they call you, it's what you answer to.' W.C. Fields.
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Blackplate
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Re: Technical Talk
Excellent, thanks. I can picture that. There's a CCU and I think a blocktube (?) yet to look at that I don't 'recognise' and I'll have a much better understanding. It's not rocket science, seems more complicated! An art to balancing up the various conditions anyway. Cheers T
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Renegadenemo
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Re: Technical Talk
The Bloctube control is just a lever in the cockpit that opens the throttle 30 degrees for starting. The CCU or Combined Control Unit is basically the engine's fuel injection system. Fuel to the main burners is regulated through a valve controlled by the throttle. The CCU also controls startup and has a barometric pressure control to compensate for pressure changes with altitude. It's quite a piece of kit.There's a CCU and I think a blocktube
I'm only a plumber from Cannock...
"As to reward, my profession is its own reward;" Sherlock Holmes.
'It ain't what they call you, it's what you answer to.' W.C. Fields.
"As to reward, my profession is its own reward;" Sherlock Holmes.
'It ain't what they call you, it's what you answer to.' W.C. Fields.
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Blackplate
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Re: Technical Talk
I see, it sure is an education. I haven't had the diary to refer to these past few days so this really helps. Thanks. So, the bloc tube, dare I say it, acts like a (fuel only) choke? Left off on 'hot' starts? From memory, was there a second lever? Main throttle?
Ok & the CCU I suppose is analogous to the modern ecu on a fuel injected reciprocating engine but because has no digital data input runs with/from an ambient pressure balance valve like a diver's first stage?
If that's ok, I think I get the complete general picture.
PS thanks for the daily pictures. I think being so consistent over the years with them is a winner. Bp
Ok & the CCU I suppose is analogous to the modern ecu on a fuel injected reciprocating engine but because has no digital data input runs with/from an ambient pressure balance valve like a diver's first stage?
If that's ok, I think I get the complete general picture.
PS thanks for the daily pictures. I think being so consistent over the years with them is a winner. Bp
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Renegadenemo
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Re: Technical Talk
Once the engine is running the CCU is basically a tap that admits more or less fuel depending on throttle position. It is opened 30 degrees for starting in all conditions, hot or cold, and when closed the engine stops. The Bloctube control - so called because it was made by a company called Bloctube Controls - is just a precision lever that opens the tap 30 degrees. The tap has 90 degrees of travel all-told so 30-90 is controlled by a foot throttle but the CCU is not like a 1st stage. It merely allows fuel to pass through itself and be metred by the throttle valve.So, the bloc tube, dare I say it, acts like a (fuel only) choke? Left off on 'hot' starts? From memory, was there a second lever? Main throttle?
Ok & the CCU I suppose is analogous to the modern ecu on a fuel injected reciprocating engine but because has no digital data input runs with/from an ambient pressure balance valve like a diver's first stage?
It has some additional features for startup and altitude compensation but mostly it's as above.
I'm only a plumber from Cannock...
"As to reward, my profession is its own reward;" Sherlock Holmes.
'It ain't what they call you, it's what you answer to.' W.C. Fields.
"As to reward, my profession is its own reward;" Sherlock Holmes.
'It ain't what they call you, it's what you answer to.' W.C. Fields.
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Blackplate
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Re: Technical Talk
Once again, many thanks! I get it all so much clearer now. I thinks it's fantastic that the boat would be close-on competitive today with the speeds achieved in those days before digital control of engine, boat systems and CAD modelling. It's designed the old way, through intelligence, experience & the 'seat-of-your-pants' development. I've got to respect that. I'm somewhat impressed by the rebuild and the tin bashing involved, I think its a bold thing to have taken on all those years ago. Its a deeply impressive set of skills from fishing it out of that depth of water to up-and-running (so I do put my hands in my pockets for the project now and then in my own small way).
One small question left and I'll try and leave it for the while (honest!), How are the ignition signals generated, don't tell me they use a distributor & points?!
One small question left and I'll try and leave it for the while (honest!), How are the ignition signals generated, don't tell me they use a distributor & points?!