![]() |
If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
|
#1
|
|||
|
|||
![]() "Cub Driver" wrote in message ... The question is are we capable of producing superior prop aircraft than the great fighters of WWII and what configuration would it take? I'm not sure what the engine would be. Is there an off-the-shelf turbine engine that could be tweaked to the war-emergency power requirements of a fighter aircraft? I'm not saying there is none! I haven't the faintest idea of what the capabilities of existing turbines might be. But note that the horsepower of front-line fighters in WWII was more than doubled in four years, as an example of wartime requirements. Also, lives were cheaper in those days. The Germans accepted a man-killer like the Me 163 into front-line service, and the Me 262 would also be unacceptable today, with its 10-hour engine life. The engine entered service with an MTBO of 25 hours which was well established. (about 16 missions) Manufacturing complaince and service realities degraded this to 10 hours for a while. Still if I was an Ju 88 pilot I'd prefer converting to the Jet than the Me 109 given that my combat skills and the concentraion of allied aircraft. Mean time between overhall was 25 hours not total engine life and was a problem of lack of chromium and particularly nickel at one level and at another level poor manufacturing quality control compliance. (This made the biggest difference; the use of unskilled factory labour versus technicians and tradesmen who did not need supervision or detail instructions) Injector burners were the most heavily consmed item but could be easily replaced. The 6 Combustion chambers were made of simple carbon steel coated in aluminium and needed to be replaced at 25 hours. Both the hollow air cooled tinadur and cromadure turbine blades were removed at 25 hours, x-rayed and if OK replaced for a further 10 hours. Theoreticaly engine overhaul life reached 60 hours in the latter model s. Earlier engines, the Jumo 004B1 had solid blades while the Jumo 004B4 had hollow aircooled blades and was more reliable. The first experimental blades had lives of 4 hours to over 100 hours due to manufacturing spread. What the Jumo 004B lacked was a throttle bypass system to bypass excess fuel as the compressor spooled up. The control system did rely on RPM and pressure but this was inadaquete in cases of rapid throttle movement. The over supply of fuel could raise combustion temperatures by 200C which had the effect of burning through combustion chambers and turbines. The BMW 003A used on the Arado 234C and He 162 volksjaeger despite lagging 9 months behined and actualy having its control system derived from the Junkers model was more sophisticated in having a throttle bypass system. The annular combustion chamber on the BMW 003A lasted 200 hours, the turbine could be removed, inspected and replaced in less than 2 hours, the engine did have a throttle limiting system. Unlike the 004 the engine did not need to be stripped down. The Jumo 004C and Jumo 004D both entered production (for use in prototypes) and had increased thrust of 1050 and 1100kg due to detail refinements. In the case of the 004D this included duel zone combustion to overcome the atomisation problems that cuased flameouts at high altitude and idling. (These engines all entered production but not service. A Jumo 004C apparently propelled an Me 262 to 584mph.) Part of the problem the engineers faced was the fuel. Although designed for running on the diesel based J2 fuel for reasons of economy and safety this added a 2 stage startup initialy on a lighter fuel as well as necesitating fuel systems that could cope. Some Me 262 missions were flown with crude oil in the tanks. The crude oil was refined only by centrifuge, then heated and pumped into the tanks. all the best -- Dan Ford email: see the Warbird's Forum at www.warbirdforum.com and the Piper Cub Forum at www.pipercubforum.com |
Thread Tools | |
Display Modes | |
|
|
![]() |
||||
Thread | Thread Starter | Forum | Replies | Last Post |
Questions Regarding Becoming a Marine Fighter Pilot. ? Thanks! | Lee Shores | Military Aviation | 23 | December 11th 03 10:49 PM |
Veteran fighter pilots try to help close training gap | Otis Willie | Military Aviation | 0 | December 2nd 03 10:09 PM |
Sensenich W72CK-42 propeller for sale | Steven P. McNicoll | Aviation Marketplace | 0 | November 18th 03 03:02 AM |
A-4 / A-7 Question | Tank Fixer | Military Aviation | 135 | October 25th 03 03:59 AM |
Joint Russian-French 5th generation fighter? | lihakirves | Military Aviation | 1 | July 5th 03 01:36 AM |