Rear Admiral Parry does not hold back re the engine problems on the latest destroyers
I believe the device you are referring to is actually a heat-exchanger, which is used to transfer waste heat energy from the exhaust back into the intake air to improve overall thermal efficiency. The fact that matlots can't grasp the difference is a shortcoming in the matlot intellect rather than the boy-racer one.
PDR
I believe the device you are referring to is actually a heat-exchanger
When the intercooler pump in my Teutonic tourer failed, the supercharger was inhibited whenever an 'inlet temp high' condition was sensed. The performance was worse than with the normally aspirated version as the EMU defaulted to a very conservative condition; fortunately it was an easy and quick extended warranty fix.
Back to aviation and matelots, wasn't it the Sea Vixen which had the ultimate blend of mixing systems - with fuel cooled, hydraulically driven AC generators?
Back to aviation and matelots, wasn't it the Sea Vixen which had the ultimate blend of mixing systems - with fuel cooled, hydraulically driven AC generators?
Gentleman Aviator
wasn't it the Sea Vixen which had the ultimate blend of mixing systems - with fuel cooled, hydraulically driven AC generators?
May I put in a counter bid for the windscreen wipers on the mighty Wessex?
Electrically driven hydraulic pumps which drove Bowden cables to the wipers.
The final touch of genius by Mr Sikorski was to locate the Captain's wiper motor between the co-pilot's feet and vice-versa.When one of the pumps leaked hydraulic fluid copiously - which was often - one had to choose as handling pilot either one whose feet were swimming in OM-15, but who could see out, or a pilot with dry feet who couldn't.
And it always seemed a little "over-engineered" when the requirement was to wipe a flat screen on an aircraft with a Vmax probably lower than BEags' "Teutonic Tourer"
Ah......the Wessex wiper motors! On one of my early solo fights (in the rain) in the queen of the skies it was somewhat distracting to observe the smoke and smell of burning coming from the co-pilots wiper motor. After some anxious moments wondering how this was possible and considering multiple turning off of switches, a dim recollection from ground school about this bizarre arrangement provided a solution - and saved us from the embarrassment of the crewman in the cabin firing off the fire extinguisher whilst struggling to climb up through the co-pilots seat.
And they were considerably less effective on our flat screen at slower speeds than on the curved and faster E-type ..... back in those days Teutonic tourers were for insurance salesmen not lords of the skies.
Hat, coat, door....
And they were considerably less effective on our flat screen at slower speeds than on the curved and faster E-type ..... back in those days Teutonic tourers were for insurance salesmen not lords of the skies.
Hat, coat, door....
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JENKINS
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How about the British light turbine twin with an Avgas cabin heater?
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How about the British light turbine twin with an Avgas cabin heater?
Huh? Dilettante boy racers may fit turbochargers or superchargers in pursuit of speed and power. Serious boy racers will also fit an intercooler between the blower and the cylinders to reduce the charge temperature, increase charge density and provide even greater power. Pretty well every turbodiesel car and truck on the road has an intercooler to increase the maximuym power capacity and improve efficiency.
I believe the device you are referring to is actually a heat-exchanger, which is used to transfer waste heat energy from the exhaust back into the intake air to improve overall thermal efficiency. The fact that matlots can't grasp the difference is a shortcoming in the matlot intellect rather than the boy-racer one.
I believe the device you are referring to is actually a heat-exchanger, which is used to transfer waste heat energy from the exhaust back into the intake air to improve overall thermal efficiency. The fact that matlots can't grasp the difference is a shortcoming in the matlot intellect rather than the boy-racer one.
As I said, they may well fit superchargers but I guarantee you none have ever fitted an intercooler. Look up what an intercooler is. No car or truck on the road has one.
To quote yourself, but in the pursuit of accuracy this time, and to repeat myself, "I believe the device you're referring to is actually an "aftercooler". If the motor industry chooses to misname a technical aviation derived device there is no need for us to do so too, is there?
Quite unlike your toy Vauxhalls it looks as if the device on the ships is indeed an intercooler as it is placed between the low and high pressure turbines - unless I've misread the script.
You might also notice I made no comment on the heat exchanger so correction on that point is superfluous to say the least.
Last edited by Wageslave; 2nd Aug 2016 at 21:15.
@esa_aardvark,
Given the impressive efficiencies (they come within a nat's whisker of the theoretical 50% limit) that are achieved by the modern large ship diesel engines, there's nothing left in the exhaust to recover after the turbo chargers and whatever other tricks they employ. They even go as far as to use the air compressed under a descending piston to push up the adjacent one on its up stroke.
At the expense of fuel efficiency, yes. The good old Olympus has about the same power output, ish, will work for 1,000,000 years but will drink more fuel. And Olympus is a much better name than WR21, or Trent, or whatever.
Diesels aren't as useful in a warship - slow to respond to the telegraph, and they're the wrong shape (tall) and take up a lot of space. A 100,000 HP diesel in a 130,000 ton freighter is, comparatively speaking, just a small unit at the back of the ship. The same engine in a 8,000 destroyer would pretty much mean that there's nothing else on the ship!
As for not liking running in hot water - the Persian Gulf gets pretty warm, as any submariner who has served out there (plus any submarine equipment designer) will tell you. I'm told that the ambient internal air temperature on T boats whilst submerged in the Persian Gulf during the summer was in the order of 50 deg C. Hot. Submarines there are big black rubber coated things basking in warm shallow waters under a scorching sun, and the T's air con plants were designed for the North Atlantic... Now imagine living and working in that for 2 weeks with no shower... yeurk! Round of applause for our submerged friends I think.
No one should be surprised that the Gulf sea water gets hot. RR are the design authority for literally every RN engine working out there, so they surely know (not they they built the recuperator). No doubt that somewhere within the inbox of a variously inhabited designation in Abbey Wood is a concerned email from people who know to people who need to know, but weren't there long enough to be able (or be obliged) to do anything about it.
Engine 10 cylinder 100000hp diesel. I am sure that you
could cool down the diesel exhaust somehow, intercoolers?
could cool down the diesel exhaust somehow, intercoolers?
Would it be better to go back to such low tech that actually works.
Diesels aren't as useful in a warship - slow to respond to the telegraph, and they're the wrong shape (tall) and take up a lot of space. A 100,000 HP diesel in a 130,000 ton freighter is, comparatively speaking, just a small unit at the back of the ship. The same engine in a 8,000 destroyer would pretty much mean that there's nothing else on the ship!
As for not liking running in hot water - the Persian Gulf gets pretty warm, as any submariner who has served out there (plus any submarine equipment designer) will tell you. I'm told that the ambient internal air temperature on T boats whilst submerged in the Persian Gulf during the summer was in the order of 50 deg C. Hot. Submarines there are big black rubber coated things basking in warm shallow waters under a scorching sun, and the T's air con plants were designed for the North Atlantic... Now imagine living and working in that for 2 weeks with no shower... yeurk! Round of applause for our submerged friends I think.
No one should be surprised that the Gulf sea water gets hot. RR are the design authority for literally every RN engine working out there, so they surely know (not they they built the recuperator). No doubt that somewhere within the inbox of a variously inhabited designation in Abbey Wood is a concerned email from people who know to people who need to know, but weren't there long enough to be able (or be obliged) to do anything about it.
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Bit of thread drift, but you will find that some cars do indeed have intercoolers. Perhaps you aren't into modifying cars and so are unaware of which group add intercoolers quite often.
Bit of thread drift, but you will find that some cars do indeed have intercoolers. Perhaps you aren't into modifying cars and so are unaware of which group add intercoolers quite often.
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Ok,
1. They are very reliable. The gas turbine is not the problem on the T45. I will stick my neck out and say that gas turbine engines are more reliable than piston engines as a general rule. If you tried to get the similar performance from a diesel engine that you get from a gas turbine, the diesel will have more failures. Look at aero engines. Astonishingly reliable.
2. The diesel engine in that freighter took a very long time to get that freighter up to the 25kt speed you quote. Warships have a requirement to be very much quicker both in top speed and in acceleration and deceleration. The power to weight and size ratio of a gas turbine is vastly superior along with much faster response times.
3. Due to the way drag works in displacement vessels, very simplistically without going into Froude numbers etc it is easier to get a long ship to a high speed than a short ship. A diesel engine that could get a relatively short warship to 30+ kts would take up most of the ship.
https://en.wikipedia.org/wiki/Hull_speed
Incidentally, that freighter may have once done 25Kts in a trial, but what speed did it actually bimble around at? I'm guessing no faster than 18kts, probably around 15kts?
That is the speed range most ships traverse the world at, and that is the speed diesels excel at.
4. You mention maintenance. Gas turbine units can be swapped out through specifically designed routes in the ship. The Spares are carried on RFAs. Good luck with that on a freighters vast Diesel engine.
Plus you need more than 1 engine for redundancy etc.
Ask yourself why warship designers all over the world are not using diesel engines.
Is it because they are all idiots, or is it perhaps slightly less simplistic than you imagine?
Note that steam powered warships were just as quick (many slightly quicker) and nearly everybody (super carriers and big subs aside, they stuck with steam!) moved from steam to gas turbine once they became available.
...hydraulically driven AC generators?
Whereas an engine driven accessory drive (before the days of cross-drives) is clearly dependent on a serviceable engine, an hydraulic motor needs hydraulic pressure from the main hydraulic system, no matter how many pumps are actually working at the time. Probably easier to maintain constant motor speed as well.
But did the 'Vixen really use such a system?
Barnstormer, yes, thread drift but I say again, no car or truck has to my knowledge ever been fitted with an intercooler, as clearly explained in my post which you may care to read thoroughly in order to find out why.
Ecce Homo! Loquitur...
Not according to this Flight article in the 1960s. Yes, a hydraulic pump driving an alternator for the AI radar. But also two 28V generators off the engine auxiliary geRbox.
Most of the Sea Vixen systems used 24 Volts DC. Some of the instruments and navigation systems used 115V AC, which was provided by inverters. AC for the Red Top and Firestreak systems was provided by two hydraulically driven Alternators.
If you go to the "Sea Vixen.org" website and look under "History" you will find various documents including Pilots' Notes.
If you go to the "Sea Vixen.org" website and look under "History" you will find various documents including Pilots' Notes.
Thanks, Keith!
It would seem that the Red and Green hydraulic systems powered the AC alternators for the radar and missile systems - and that there was indeed a heat exchanger in each engine fuel feed line, the purpose of which was to cool the fluid of these general services hydraulic systems as well as to heat the fuel for filter de-icing.
What a very complicated aeroplane the 'Vixen truly was!
It would seem that the Red and Green hydraulic systems powered the AC alternators for the radar and missile systems - and that there was indeed a heat exchanger in each engine fuel feed line, the purpose of which was to cool the fluid of these general services hydraulic systems as well as to heat the fuel for filter de-icing.
What a very complicated aeroplane the 'Vixen truly was!
Last edited by BEagle; 3rd Aug 2016 at 14:08.
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Huh? Why not read the post before replying so inaccurately?
As I said, they may well fit superchargers but I guarantee you none have ever fitted an intercooler. Look up what an intercooler is. No car or truck on the road has one.
To quote yourself, but in the pursuit of accuracy this time, and to repeat myself, "I believe the device you're referring to is actually an "aftercooler". If the motor industry chooses to misname a technical aviation derived device there is no need for us to do so too, is there?
Quite unlike your toy Vauxhalls it looks as if the device on the ships is indeed an intercooler as it is placed between the low and high pressure turbines - unless I've misread the script.
You might also notice I made no comment on the heat exchanger so correction on that point is superfluous to say the least.
As I said, they may well fit superchargers but I guarantee you none have ever fitted an intercooler. Look up what an intercooler is. No car or truck on the road has one.
To quote yourself, but in the pursuit of accuracy this time, and to repeat myself, "I believe the device you're referring to is actually an "aftercooler". If the motor industry chooses to misname a technical aviation derived device there is no need for us to do so too, is there?
Quite unlike your toy Vauxhalls it looks as if the device on the ships is indeed an intercooler as it is placed between the low and high pressure turbines - unless I've misread the script.
You might also notice I made no comment on the heat exchanger so correction on that point is superfluous to say the least.
I can assure you sir almost every truck on the roads does have a inter cooler !
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Intercooler
An intercooler is any mechanical device used to cool a fluid, including liquids or gases, between stages of a multi-stage compression process, typically a heat exchanger that removes waste heat in a gas compressor.[1] They are used in many applications, including air compressors, air conditioners, refrigerators, and gas turbines, and are widely known in automotive use as an air-to-air or air-to-liquid cooler for forced induction (turbocharged or supercharged) internal combustion engines to improve their volumetric efficiency by increasing intake air charge density through nearly isobaric (constant pressure) cooling.