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FM/DM threads Everything about FM/DM in CoD |
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#1
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So we have JtD pointing out that a change in engine RPM will result in an change in prop RPM And we have a conflict between what Crumpp and Steinhilper are saying, i.e. Steinhilper saying change the RPM Crumpp saying maintain the RPM Thus the only thing left is to decide who do you want to belive Crumpp or Steinhilper
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Theres a reason for instrumenting a plane for test..
That being a pilots's 'perception' of what is going on can be very different from what is 'actually' going on. |
#2
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Jeez, stop being so dense. Obviously Crumpp, Steinhilper is just a pilot of the era, he knew nothing about aerodynamic engineering. Duh.......
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#3
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You change rpm to achieve a given performance. For example, best climb rate is acieved at a specific rpm and manifold pressure. Steinhilper is changing rpm and manifold pressure in this case to an overboost or combat power rating. Because his propeller is not constant speed, he must coarsen the pitch to maintain that rpm. Basic propeller operation.... Only difference is a Constant Speed propeller coarsen's the pitch automatically perfectly timed to the airload. The German pilots had to do it manually. Quote:
Steinhilper and Crumpp are saying the exact same thing.
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#4
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Not at all.. I am simply pionting out that what you said about how to fly a Bf109 is in conflict with what Steinhilper said about how to fly a Bf109 At which point it is up to the reader to choose who they want to belive Thats all
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Theres a reason for instrumenting a plane for test..
That being a pilots's 'perception' of what is going on can be very different from what is 'actually' going on. Last edited by ACE-OF-ACES; 09-14-2012 at 02:52 PM. |
#6
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I would have to agree with this assement
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Theres a reason for instrumenting a plane for test..
That being a pilots's 'perception' of what is going on can be very different from what is 'actually' going on. |
#7
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Have anyone thinked about the tehcnology differense what we are having here?
What I'm meaning with this is that in 1940s they where just learning what happens near sonic speeds. oh look we are losing power because prop is going too fast, maybe we should build bigger one may that gives as more power at the same rpm oh noes its start to lose power at lower rpm than the last one! Also they did not have many other things what they now about aviation today. I really doubt that they could have calculated every thing in 100% accuracy (how many died because near sonic speed jammed lightnings controls?) Even the engines where little bit different. For example we have synthetic oils what they did not have back at the days. -------------------------- I had one more point about the pitch twingling thing in my mind when i remembered all those 2-stroke engines is busted years back. I burned hole in couple of piston because i drove too "fast" for the engine to cool down. After second engine, I learned when i was driving straight long road and having accelerated to the max i needed to relax the throttle for a couple of moment and accelerate again. This acceleration deceleration cycle gave much better average speed than what speed would have been with the highest possible rpm for not overheating the engine. What if they did the same with bf109? Little bit Overrev/overboost which give spike in the temperature and little cool down to minimize the damage? ---> Or maybe they just they had boost and revs to add but cooling could not handle it all and they used that power reserve in short periods not giving enought time for sudden engine failure or over heating? Quote:
What if they suffling the pitch near this area giving more revs untill engine would start to noise up at .93 mach (believing it would be near braking point) lowering it to near .88 mach then pushing it up untill the noise would go up etc. They just did not know it that day what they where doing. Aw man... Sorry about huge 'what if' post... And sorry if you just lost 5 minutes of your life with it... Amateur speaking. Last edited by kohmelo; 09-14-2012 at 05:56 PM. Reason: forgot to put [/i] |
#8
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#9
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But this is a good example IMHO of where 'anecdotal evidence' is useful! Here we have a WWII pilot telling us how they actually used the equipment.. Which may/can be different from how the engineers intended them to use it.. Again, not enough info to say anything wrt validating a flight model But from the WWII accounts, we know they did 'something' that seemed to improve the performance.. How much.. We don't know for sure But as for 'how' they did it I would be more incline to take this WWII combat pilot's accounts over some civilian pilot's interpretation of the account some 70 years after the fact
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Theres a reason for instrumenting a plane for test..
That being a pilots's 'perception' of what is going on can be very different from what is 'actually' going on. Last edited by ACE-OF-ACES; 09-14-2012 at 05:07 PM. |
#10
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![]() If you understood the mechanics of how adjustable pitch propellers work, you would know it is true.
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