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Guest prbeau

Mixture control question.

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Guest prbeau

First, I am NOT a pilot. I fly the FS2004 MAAM B-25 ONLY for fun, so please excuse my complete ignorance about some of this stuff, and I hope my question is "worthy". Oh yeah, the MAAM BT is a beautiful piece of work!I know what the mixture control actually does, you know, leans or enriches the fuel air mixture to the engine. But neither the HTML manual, nor the re-printed PTM, or any of the videos explain how to use it. When do I lean it? How much? How do I know what it

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PaulI am no pilot either, and so shan't start to begin to try to explain the difference between the rich and lean settings on an aircraft, as a quick Google or look at any aviation tutorial site will tell you all you need to know about mixture control in general. I notice that you're fairly new to these forums: I shouldn't be too impatient about not getting answers to posts immediately, as people are all volunteers around here! Because they don't have an answer for you the moment you personally require one doesn't necessarily mean "nobody here knows either" or will not give you an answer in due course! We're all on the beach, or fighting hurricanes!Anyway, basically, the higher you go, the more you want to lean your engines in thinner, cooler air. You'll hear the engine note change too; personally, I set my mixture by listening carefully to the engine note as I gently ease back. You'll know when you've got it right, with a little experience.As for Full-Rich on all except cruise; you've answered your own question already, I think. With heavy power loads on the engines at lower altitudes, running engines lean would cause them to overheat very quickly. Basically you should climb at full rich until at least 5,000 feet density altitude and then start to ease that mix back slowly as you reach your final stages of climb, and then cruise.Note that Dave Bitzer and I have produced an add-on replicating the AUTO-RICH and AUTO-LEAN detents of the DC-3 which can be applied to the MAAM-SIM models. This will save you having to worry about your mixture settings, but give you more accuracy and realism that checking a little box within MSFS!Can't help you with BT, though. Excepting that my Cyl Head Temp gauge is very responsive, so maybe yours has got peanut butter in it. Doesn't change much on mix lever adjustment alone, no, but certainly responds to the correct combination of power settings.Mark "Dark Moment" Beaumonthttp://www.swiremariners.com/newlogo.jpg


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Mark "Dark Moment" Beaumont

VP Fleet, DC-3 Airways

Team Member, MAAM-SIM

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Guest prbeau

Hi Mark,Please excuse my dunderheaded impatience. My apologies. Your explanation is helpful. I didn't answer my own question about why full-rich on all but cruise conditions -- I had all the pieces, and you helped me put them together! The engine may run more efficiently leaned out, but at take-off, when maximum power out is needed, keeping the engine cool is more important than running perfectly efficient. I think! Not to mention that at sea level, full-rich is probably the most efficient setting anyway.Paul

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Yep, you goddit, and it's good that you're thinking these things through, I think; you already know more than many! I know nothing about radial engines, but I do know that they are very sensitive to temperature changes. They're easy to overheat if overdriven or run too lean at the wrong time, and equally easy to shock cool i.e. crack, if you back off your Manifold Pressure too quickly on descent. Mark "Dark Moment" Beaumonthttp://www.swiremariners.com/newlogo.jpg


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Mark "Dark Moment" Beaumont

VP Fleet, DC-3 Airways

Team Member, MAAM-SIM

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Guest allcott

There's a wealth of information on DC-3's and how to fly them at http://www.douglasdc3.com/including some interesting tutorials. That will explain more about the intricacies of the DC-3 mixture system, which is NOT standard and therefore needs to be handled in a different way to other piston engined aircraft. Although the principles are the same.In fact, other than Marks autolean mod which is the best solution, you might be better leaving the DC-3 in automixture in the FS settings, as this closely represents the operation of the actual system in the DC-3/R4D-6. Of course, if you are going to all the trouble of learning about leaning and mxtures, then you will find the variations in operation between the DC-3 and other piston aircraft to be thoroughly interesting.Allcott

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