HighBypass

Sky Simulations MD-11 V2.0 Partial fuel and x-feed

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Ok, so I'm a little confused as to how the fuel system manages itself, especially when loading partial fuel. No need to fill up if we're only going on a 1000 mile flight right? :)  If I fill the left and right wing tanks and say the tail tank, but not the wing centre tank, then the system transfers fuel from the tail tank into the wing centre, presumably for C of G reasons. If there is no fuel in the wing centre then engine 2 stops and I don't appear to get the crossfeeds from the left and right tanks to do anything; I "should" be able to have them supply engine 2 if needs be surely? Or at least transfer fuel into the wing centre. (This is no PMDG hence my use of the word "should"). In addition I think that the engine 1 (left) and engine 3 (right) crossfeed buttons are swapped over...

Could any more knowledgeable members please help? Thanks in advance.

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First if all you fill three main tanks equally. For short hops you need these only. For long range i use Topcat MD11 loadsheet to calculate distribution for Tail and Aux.

And keep Fuel System auto.

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Posted (edited)

Are the developers monitoring the threads here?  I've sent them an email but never got a response. 

EDIT: 

It just occurred to me that what I wrote above could be interpreted negatively... and that is not how I meant it.  My reaching out to them via email was not related to customer support, and I'm sure they do a great job with that.

 

Edited by DaveCT2003
Ensure my comment wasn't taken negatively
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Thanks for your replies, gentlemen. Kris - ah.. yes.. one tank for each engine. The manual does mention that each engine is supplied by the appropriate tank, but typically :) I kind of glossed over that! I had been treating the MD like other planes in my fleet, but the airliners all have two or four engines - the centre tank can and is, emptied first. The freeware md-11 I had previously also appeared to work the same way IIRC, hence my mistake.

After burning a fair amount of virtual jet fuel whilst ground running earlier this afternoon, I did find that the left and right tanks will supply engine 2. I just had to go to manual mode then press the engine 2 crossfeed. Again, my mistake in thinking that a crossfeed switch feeds FROM the associated tank. This system feeds INTO the engine you wish to keep running. The centre tank was not being refilled by the left & right, they were just feeding engine 2. I'm not sure if the synoptic screen is displaying correctly; there was a green line from the centre tank crossfeed showing it was activated, but I would have thought that there would have been green lines from the left & right tanks as they were now supplying engine 2..

I currently use onlineflightplanner.org for quick and easy FSX flight planning. This gives me the total amount of fuel for a flight, I just need to learn to divide by 3 for the MD-11 on shorter trips! Seeing as the FMC on this bird is not up to much, would it be worth me spending a few euros on purchasing the TOPCAT software do you think?

Dave, I hope you're well. Long time no see (my fault). I don't seem to be able to find an email for Sky Simulations. Perhaps I should contact Just Flight in the first instance. However, I don't think I need to on this occasion, apart from to express my support as a "lite" simmer for a decent (if slightly overpriced imho) FSX MD-11, given that PMDG's bird is relatively unobtainable and would require a lot more studying before I got her off the deck!

Thanks again!

 

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In all situations other that system fault or some kind of tank damage you operate in Auto. If in Auto your MD11 runs into some strange cross tank to engine logic then maybe you should reinstall? Do you have SP1 installed?

 

Topcat also gives you proper V speeds and some other take off/ landing reference data. But if you are flying short hall only and use default V speeds calculations only you may skip it. Although its a great tool which u can use with 744, 757, A320 and some other (incl. 772).

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I do have SP1 installed yes. My discovery of a tank 1&3 "workaround" was my lack of knowledge of the MD-11 tank distribution and usage.It may be that the auto system realised that the quantities were so far out of whack that the plane expected me to do something about it?

I carried out a flight from Louisville to Portland, Oregon (well why not?) which only required around 93k lbs of fuel. I split that equally between the three tanks and left everything in auto. The flight went well!

Some time into the flight I discovered that the fuel system had placed a small amount of fuel into the tail tank. 45 (gallons?) displayed on the overhead panel readout.

I'll hold off reinstalling the plane for now and see how I get on.

 

Thanks for your replies. :cool:

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As far as i remember there always should be some small amount of fuel in Tail, try to put there 65 lbs prior the flight.

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