CrashTronic

Thanks @metzgergva @Jason Baxter

@Pilot53 can you provide screenshots demonstrating this behavior? I'm on a work trip right now so i don't have access to xplane. Please perform any testing at standard atmospheric conditions. Thanks! Thanks!

@Jason Baxter Can you provide screen shots of this occurring as well as a list of weather addons you are using? Thanks

Hi Dave, PMDG appear to be focused on the completion of the FSX/P3D release cycle. @rsrandazzo said the PMDG team would evaluate the next steps after they complete the work. Except for a quick code update to get the rudder to move in the correct direction, it is very flyable at low blower settings. I know this isn't much to go on but PMDG will update when they have more specific information to contribute. Hope this helps, Mike

Cool if you get a chance, post what changes you made and the effect. Thanks!

Good to know. Since the aircraft was made for X-Plane 10 we weren't guaranteed functionality in 11. I can't locate a detailed change log regarding the new changes and as an additional complexity the supercharger code is probably in the Pmdg dll.

Hey Robert, You are correct. the fuel is injected in the Carb which is why in the other examples I don't denote the fuel location. And it does appear the engine is running more lean, but in the sense of the weird dynamics of perfect sim combustion. There is no longer a stoichiometric balance between fuel and air so the excess air is ported out the exhaust but the same power is produced. Rather than the usually observed scenario of, same air and reduce the fuel which reduces power. The same potential is being injected into the cylinders but there is now an excess of air which is not being used for combustion. Which is why it feels like a fuel metering issue in the real world sense but in the coding sense is probably something else

Evidently I can no longer edit posts or I am having an error between monitor and keyboard Correction: is exactly the way as in the image at the bottom of the above post. So it clearly can not be an issue with my hypothesis as the quoted configuration

So I've tested pretty extensively in XP10/11 and while not particularly helpful, it appears to be either the new prop physics for some reason or the fuel leaning in the carbs or the code dealing with supercharger switches. I am unable to locate a detailed change log for XP11 aside from the release notes so I really can't go further in the research. If this where a real aircraft I would say the effect appears to be the result of one of the following: the carburetor being located before the supercharger but the MAP gauge probe being located after the supercharger. ======CARB====Supercharger=========MAP======ENGINE or possibly more accurately it is like the carburetor is only a throttle body and fuel is being metered at the carburetor but mixed with air aft of the supercharger. This would be most synonymous with a fuel injected system metering fuel using mass flow data from before the supercharger, not after. ======CARB====Supercharger==(fuel)===MAP======ENGINE which is contrary to the actual manner the system should be operating in, again, not through any direct errors made by PMDG but due to a shift in the X-Plane 11 code revision from 10. Thanks, Mike

I can confirm there is something different between XP10 and XP11 that handles the engine differently. I have posts out to find out what it might be.

Hey Volkira Have you submitted a support ticket? The forum is primarily for user to user support. It sounds from your situation that you may be better suited with direct support from PMDG. They have a pretty good turn around time for tickets like yours. If you do contact them and get a resolution it would help to update this thread again in case someone else has an issue. Mike Edit: Dan beat me to it.

I've had an interesting revelation regarding BMEP, and MAP. This may end up as a string of consciousness so hang on. Hypothesis: Something isn't right with the engines supercharger high/low vs BMEP Definitions 1)Mean Effective pressure mathematical definition: 2Pi*torque*number of revolutions per power stroke/displacement The result of the above is for a given engine the only criteria for MEP or BMEP is the amount of torque the engine crankshaft is stressed to. In the Prop world this is a function of induced and parasite drag on the prop vs amount of power produced by the engine. From the pilot's perspective regarding an operating engine this means there is a proportional relationship between throttle, blade angle and torque on a given engine. I tested the DC-6 and found that the reported BMEP numbers are correct but the problem is elsewhere in the engine sim dealing with the MAP and the supercharger setting. going from Low to High appears to only provide a manifold pressure boost with no corresponding fuel flows to increase power. The effect is the MAP is raised but the power output remains the same requiring a lower throttle to maintain the required MAP to keep from damaging the engine but as you do so, fuel flows are reduced, power is then lessened and at any given MAP you end up with less power at the same MAP in the High blower than you do in the Low blower

Regarding this issue, I'm not sure about the prop model, BUT from my own experiments the BMEP is accurate it's the lack of additional power caused by moving into high supercharger. All you get is a MAP boost. I pulled up the engine data in XP11's overlay and when you flip the Supercharger switches you get a boost to MAP but no change in power but the damage model still takes into account the overboost. the results dictate you decrease the throttle to decrease the MAP which actually puts you at a lower power than in low supercharger. it robs about 500hp/engine if you go into high and then reduce to the appropriate MAP setting. I'm trying to research this issue a bit more but i think the code may lie in the pmdg dll.

Thanks Dan. I was wondering about that and I think XP may become my primary sim with how nice it is and I would thoroughly enjoy an update to it. The CRJ may be the cutie at work irl but the DC-6 is my true love back home.

Good morning/afternoon all, I was previously a DC-6 owner in FSX:SE and now the same in XPLANE 11. I know the DC-6 was developed for 10 but I accepted the risk and so far have been loving it. A quick question. I noted somewhere, I can't find it now after searching, a reference to the supercharger switches not really doing much in xplane. I encountered the same issue, a slight blip in MAP but ultimately it returned to the same value. That behavior is vastly different to the FSX:SE experience and I was wondering if this was an XP11 or an XP thing in general. http://xplane.wikia.com/wiki/Engine_Specs Additionally I noticed that the BMEP values under the same atmospheric conditions are a bit different between the 2 sim versions, not that one is more right than the other, because I honestly don't have data to make that conclusion. What might cause the discrepancy? Thanks for your attention to this post, Mike

fair point regarding temperature but in this case I disagree with your assessment because as I understand the scenarios being presented, temperature is irrelevant because all the presented theoretical engines are operating under the same atmospheric conditions and no previous mention of intercoolers has been addressed. As such manifold pressure still represents, to the pilot, the best indicator of air mass flow rate. If we want to get absolutely correct, ignoring partial pressures, under the ideal gas law Pv=nRt, the amount of gas (moles, n) is directly proportional to PV/RT.

I submit John Deakin's excellent engine management articles https://www.avweb.com/news/pelican/Pelicans-Perch-15-Manifold-Pressure-Sucks-182081-1.html https://www.avweb.com/news/pelican/182544-1.html The first article on, "Those fire breathing turbos" covers supercharging I see some concept obfuscation going on. Let's get everyone on the same page. I remember this discussion from "that other also amazing propliner"(tm) some background: Manifold Pressure is the absolute barometric pressure the engine is operating at. Case in point, what is the difference between a blocked intake and a closed throttle....none. To determine power production in ANY piston engine you need 3 pieces of information, 1) how much air (MAP), How much fuel (PPH), and how fast the combustion occurs (RPM). they are all proportional, increase one and you increase total power. When you slow down a super charged engine, the supercharger will spin more slowly but the effect of slowing down the pistons has a larger effect on the MAP than the slowing of the supercharger. Go read those articles they are amazing and very informative

Thank you!

Hey All, WAAAAAAAAY back on the aft overhead there are the ignition advance switches, which change the engine ignition timing based on the switch position. Is this implemented? I couldn't tell if there was a difference in flight. Thanks

the answer is here:

Understood. I may jury rig a quick and dirty XML in the mean time if I can bother myself to do it. I did notice interestingly enough, the DC-6 will NOT allow an engine to fail on take-off. It cancels the failure and restarts the engine. The only exception is a fire.

Hello! Is there a procedure for the autofeather test and or activation of the autofeather system for takeoff? Thank you Mike Edit:

Agreed, I am witnessing the same behavior in FSX-SE. Running 1.20.8418 as well

I followed the procedure per the manual as well and the indicator lights do not come on. I am not sure what I am missing

I've done DFW-NRT and LAX-HKG numerous times at 1x. Sometimes I find it fun, but I treat it like a real flight and let the other crews; otto1 and otto2 fly.