#21
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AP 1590B Merlin II and III Aero-Engines:
"257A. In its unmodified condition, the boost control cut-out valve permitted the boost pressure to rise very considerably." |
#22
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Woaaaww... "Considerably" ?
@Wedge : can you consider that given the Spit FM are alrdy optimistic adding the extra boost cld hve proved so outraging that the devs might hve decided to lower this value on the Spit ? Last edited by TomcatViP; 09-16-2011 at 08:42 PM. |
#23
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Yes considerably ...
http://www.spitfireperformance.com/spit1-12lbs.jpg Quote:
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#24
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If however I well understood, the boost cut out was put because this high pressure was damaging to the engine in the long run and therefore its use was limited to real emergency cases.
Could the fact that it is limited right now be linked to that perhaps? |
#25
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TomcatVIP, would you please stop posting if you aren't going to add anything other than hearsay to this. From reading the thread =XIII=Wedge has made some very interesting points - I for one am trying to understand the detail of this but clearly I'm a bit more stupid than other pilots. Understandably I don't really appreciate you throwing in undermining comments based on your own personal knowledge and trying to deride other posters arguments on the spurious suggestion that the length of registration on a forum somehow dictates your knowledge on the topic. Should Jeffrey Quill have registered today would you be telling him the same thing?
Frankly, if you are one of those people that doesn't believe that the RAF had the 100 octane in use on fighters thus achieving 12lbs boost then I'm afraid I don't think I'll be able to take anything you say seriously, ever. I'm confident that the development team aren't so unreasonable when it comes to looking at evidence. =XIII=Wedge, please carry on. |
#26
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Function of the Automatic Boost Control
My understanding was that the original reason for the throttle being design with an automatic boost control was to reduce the workload on the pilot and prevent over-boosting the engine. It allowed them to set the desired boost pressure with the throttle lever and the ABC would ensure that that desired pressure setting was maintained up to the rated altitude. Without it the pilot would constantly have to keep adjusting the throttle to maintain the same boost as the plane changed altitude. Using the boost cutout disables this function. @TomcatViP - It is possible, but it is more likely that pressure to release the product meant that development was scaled back. There is clear evidence of this, due to having two variants of spitfire MK 1A that differ only by propellor. (DH-2S and Rotol-CS) No problem with this it happens all the time, features are dropped to get a release to the market place. However if you take these pressures out of the equation, a more realistic flight model is still a desirable attribute and is infact a major selling point. Red vs Blue arguments don't really come into it. Multiplayer is an important aspect of the game, but with out greater realism we might as well be playing Tom Clancy's H.A.W.X. Last edited by =XIII=Wedge; 09-18-2011 at 03:47 PM. |
#27
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Quote:
Some notes: You discribe a "variable datum type" automatic boost control. Early production Merlin II engines had a "fixed datum type" automatic boost control (however even the manual mentions that these are replaced by the "variable datum type"). As you already wrote with a "variable datum type" boost control each throttle setting gives you always the same boost (up to rated altitude). The "fixed datum type" had the follwing drawback: AP 1590B Merlin II and III Aero-Engines Quote:
What the "modification" to the boost control does is simply limiting the boost pressure to rise above +12lbs even if the boost control was disabled. However my understanding is that you don't have the benefits of the "variable datum type" boost control anymore (as long as boost control cut out is enabled). In later Merlin marks this was changed and the "boost control cut out" didn't really disable the boost control but it did set a higher boost for each throttle setting. |
#28
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So given that we currently have an earlier Spitfire using only 87 octane fuel:-
With the ABC enabled (normal situation)
Does this seem like a reasonable analysis of the issue? Last edited by =XIII=Wedge; 09-18-2011 at 04:18 PM. Reason: typo |
#29
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I feel more clever already
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#30
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Really ?
If you get 6.25 op. WHy wld you hve 17 then ? Just a reminder 6.25x2=12.5 6.25x3 = 18.75 So nearly two third of Merlin "power" (let's say for a second that boost ctr linearly the available power) was spared from the normal eng op that was used to qualified the type in the RAF FC ! What do you think they tried to spare Sidney pride ? What is to be sure is that I m getting old with that endless debate as much as if the time on the CoD forum was highly boosted !! |
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