| Forum Home | ||||
| PC World Chat | ||||
| Thread ID: 97916 | 2009-03-04 04:31:00 | Qantas Airbus A380 flaws | John H (8) | PC World Chat |
| Post ID | Timestamp | Content | User | ||
| 753287 | 2009-03-05 01:59:00 | Goblin being a centrifugal engine wouldn't be to prone to compressor surges would it? The blardy poms seem to like the variable flow fuel pumps on their jet engines. You can get stall and surge in a radial compressor but afaik (or remember) it was not as common as in an axial compressor. In my post above instead of 'surge' line I meant steady running line, sometimes the engine steady running line was very close to the stall line, and as these lines are not straight, the fuel system had to be very carfully designed with kinks to get around the curves without crossing into the stall region. Stall is when there is flow separation from the blades and pressue rise is lost, the pressure downstream can then cause a flow reversal, called surge. Although almost identicle variable flow swash plate pumps were used by the UK admiralty during WW1, the Lucas pump with servo feedback to the swash plate was due to one Richard Ifield an Australian, now deceased, and father of Frank Ifield the singer/entertainer. In its day the variable flow pump filled the needs of aircraft jet engine pumps, but as flow requirements increased there were centifugal force problems associated with very large piston pumps. |
Terry Porritt (14) | ||
| 753288 | 2009-03-05 02:00:00 | On my part never Snide I meant jocular :lol: |
Terry Porritt (14) | ||
| 753289 | 2009-03-05 02:18:00 | I found a graph for the RA29 Avon engine which was a very well behaved engine and one of the most widely used, all the Avon series were well behaved :) www.imagef1.net.nz [oops, it's on its side] This shows how the acceleration fuel flow requirements were kept within the surge or stall line for a then prototype design of fuel system which went by the name of CASC. |
Terry Porritt (14) | ||
| 753290 | 2009-03-05 08:43:00 | What is "compacitance"? Is it a mangled "capacitance" or something else? From Airliners.net it appears to be a fungus problem and that affects all types www.airliners.net Fuel measurement in an aircraft is based on density and volume as volume measurements alone change with temperature. Two capacitors (built as one unit call the compacitor) sits in the fuel tank. One has a low profile and is always in the fuel and therefore the value of the capacitance varies with the density of the fuel. The second capacitor is tall and sticks out of the fuel. As the fuel level changes so does the capacitance. The measurement of the tall capacitor is compensated for density by comparing it to the low profile capacitor using a capacitance bridge. From this the exact fuel quantity is known. This is the possible source of the word Compacitance. Fungus in fuel is usually formed in the fuel water interface, and for this reason water is a no no in fuel. Water contamination in fuel is normally a supply problem and not an aircraft problem although water can come from the air that replaces the fuel as the level drops or from leaks in fuel tanks that suck in water on a pressure change (as an aircraft descends). Water checks are carried out on Aircraft before flight and on fuel at delivery time (well at least they use to be). |
porkster (6331) | ||
| 753291 | 2009-03-05 09:44:00 | I found a graph for the RA29 Avon engine which was a very well behaved engine and one of the most widely used, all the Avon series were well behaved :) www.imagef1.net.nz [oops, it's on its side] This shows how the acceleration fuel flow requirements were kept within the surge or stall line for a then prototype design of fuel system which went by the name of CASC. We should mention,the Spitfire behaved very well,perhaps a slight digression! |
Cicero (40) | ||
| 753292 | 2009-03-05 19:15:00 | We should mention,the Spitfire behaved very well,perhaps a slight digression! Well yes it did that's very true............... Here is a four part doco on the Spit well worth watching :) quicksilverscreen.com quicksilverscreen.com quicksilverscreen.com quicksilverscreen.com I thought someone may be interested in a somewhat pertinent old graph I found in the archive, after all, anything over 50 years old in NZ is regarded as a valuable antique, and often has some sort of heritage trust placed on it :clap |
Terry Porritt (14) | ||
| 753293 | 2009-03-05 19:35:00 | Was the RA29 in the airforces canberra? | prefect (6291) | ||
| 753294 | 2009-03-05 20:54:00 | Well yes it did that's very true............... Here is a four part doco on the Spit well worth watching :) quicksilverscreen.com quicksilverscreen.com quicksilverscreen.com quicksilverscreen.com I thought someone may be interested in a somewhat pertinent old graph I found in the archive, after all, anything over 50 years old in NZ is regarded as a valuable antique, and often has some sort of heritage trust placed on it :clap Thanks for those Terr,brilliant,all that was missing was prefect and the maori haka. |
Cicero (40) | ||
| 753295 | 2009-03-05 22:24:00 | Thank you Terry for posting that film. Bloody fantastic machine and exceptionally brave pilots. Sir Keith Park, along with his fliers, certainly deserves much more prominent permanent recognition for their part in beating off the Luftwaffe in 1940. I have of course been watching your clips out of order, and will view those remaining at my leisure. Thanks again. | Richard (739) | ||
| 753296 | 2009-03-05 22:38:00 | I tell my kids that Sir Keith Park was the New Zealander from Thames who saved the free world from the baddies (italians, germans and hungarians) | prefect (6291) | ||
| 1 2 3 4 5 | |||||