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rsrandazzo

[29SEP18] PMDG 747 QOTSII Update 3.00.9019 Released via OC

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5 minutes ago, JRBarrett said:

Yeah, The density setting is right there on the fuel loading page right in front of my nose. Just never noticed.

So far, my loads have been very accurate. I’m doing a 6-hour flight right now in the standard 400F. I requested 160,000 pounds, and got just a few pounds less - something like 159,980, which I assume is due to rounding.

I’ll try a full load on my next flight. I’m using the new update just released.

Right. What I'm saying is prior to the initial update to the -400 when the -8 got released, if I requested 40,000 pounds, I got 40,000 pounds rather than 39,994. Start lowering the fuel density, and the difference starts to become more noticeable at the higher fuel weights.


Captain Kevin

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Air Kevin 124 heavy, wind calm, runway 4 left, cleared for take-off.

Live streams of my flights here.

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10 minutes ago, downscc said:

Thanks Jim,  being an EE and working around industrial instrumentation and control systems for 20 yrs I know exactly what you are talking about.  Similar capacitance probes are used in the tank farms at refineries, although level measurements using ultrasound or radar is more common.  I did some googling and found alot of vendors for magnetostrictive probes that seem to be more accurate than the capacitance probes.  In either case, the density is a derived value and not something measured directly as is the case for Coriolis flow meters.  I use those in cases where I need to measure say for example exactly 3.33 kg of water, and milk terminals use them to detect when the flowing liquid changes from milk to water wash.\

Interesting stuff.

The capacitive system for aircraft fuel measurement has proven to be quite reliable over the years. It’s simple, and has no moving parts. The probes rarely fail - when they do it’s usually because they have been severely contaminated by water or biological growth in the fuel.

The probes are wired in series/parallel. The AC input to all the probes are wired In parallel from a common low impedence line coming from the FQMC, and the outputs are high Z with each probe having a discrete return line to the FQMC via coaxial cables.


Jim Barrett

Licensed Airframe & Powerplant Mechanic, Avionics, Electrical & Air Data Systems Specialist. Qualified on: Falcon 900, CRJ-200, Dornier 328-100, Hawker 850XP and 1000, Lear 35, 45, 55 and 60, Gulfstream IV and 550, Embraer 135, Beech Premiere and 400A, MD-80.

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27 minutes ago, Captain Kevin said:

Right. What I'm saying is prior to the initial update to the -400 when the -8 got released, if I requested 40,000 pounds, I got 40,000 pounds rather than 39,994. Start lowering the fuel density, and the difference starts to become more noticeable at the higher fuel weights.

Gotcha. Didn’t think the difference was significant at mid-range loads like I have been using, but I haven’t tried high loads yet, or varying the density. Though, with low density fuel, you could definitely have a situation where you will end up with less than requested weight when filling tanks to the brim.


Jim Barrett

Licensed Airframe & Powerplant Mechanic, Avionics, Electrical & Air Data Systems Specialist. Qualified on: Falcon 900, CRJ-200, Dornier 328-100, Hawker 850XP and 1000, Lear 35, 45, 55 and 60, Gulfstream IV and 550, Embraer 135, Beech Premiere and 400A, MD-80.

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1 minute ago, JRBarrett said:

The capacitive system for aircraft fuel measurement has proven to be quite reliable over the years. It’s simple, and has no moving parts. The probes rarely fail - when they do it’s usually because they have been severely contaminated by water or biological growth in the fuel

I suspect so.  The aircraft fuel tank is a much much cleaner environment that the product tanks in a refinery or truck terminal.  And you never know how much salt water you're going to get from an ocean tanker bringing you the crude.  It's nasty.  In fact when someone says they only use high octane I tell them about how refineries must trap the vapors that are released from tank trucks, barges or ships when they fill the tank.  Those vapors are compressed, cooled and condensed into a liquid and refiners will put that trash in the high octane product tanks because it will increase the volume of fuel without degrading the octane values.  Don't ever think that something is better because it's more expensive haha.


Dan Downs KCRP

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46 minutes ago, JRBarrett said:

Though, with low density fuel, you could definitely have a situation where you will end up with less than requested weight when filling tanks to the brim.

Yes, I am aware of that, because you're limited to volume at that point. But 248,000 is nowhere near close to the fuel tank volume limit. I was wondering if there's something in the coding that's trying to convert the input into gallons, and then giving you an output with the fuel density being taken into consideration, but that doesn't really explain why there's still a slight discrepancy even with the highest possible density.


Captain Kevin

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Air Kevin 124 heavy, wind calm, runway 4 left, cleared for take-off.

Live streams of my flights here.

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12 hours ago, Captain Kevin said:

I was loading it in pounds, so I'm not sure what the issue is. The PMDG fuel loader only gives you the option to load in either pounds or kilograms, so I don't know where gallons would come into play here.

It appears to me that the PMDG fuel loader takes the number of pounds that the user attempts to input, converts that number to the nearest gallon and displays that gallon figure in pounds.  I have never seen a fuel tank capacity that was rated in pounds, it was always in gallons.  


I Earned My Spurs in Vietnam

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1 hour ago, Captain Kevin said:

248,000 is nowhere near close to the fuel tank volume

Volume of liquids is in gallons.  The number of gallons a fuel tank will hold will change daily based on the temperature of the fuel. 


I Earned My Spurs in Vietnam

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12 hours ago, JRBarrett said:

the refueling truck (or bowser) meters will show the amount dispensed in either gallons or liters,

Jim,

I think that we are for the most part in agreement. 🙂

My point was (and I didn't do a very good job of explaining it)  liquid capacities are in gallons (and dispensed in gallons) and at some point during the refueling process those capacities will have to be converted to pounds for flight planning purposes.  

Grace and Peace,


I Earned My Spurs in Vietnam

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14 hours ago, Cocobellomann said:

Let‘s play

what is wrong here?

6013CF47-646D-4434-92BD-D33E8DF5FFEB.jpg

 

 

 

How has he done that? 😜

Such an engine weighs tons.

 

 

Josef K

Nice photo shop job. 


supporter.jpg

Thanks,

Randall Coultas

Spoiler

Flight Sim: P3Dv4,4/ PC: i6700K @ 4.0Ghz / Asus Maximus VIII Hero / NZXT Kraken X61 / 16Gb ram / 2 X Samsung 840 EVO SSD 500Gb / WD Black 1TB / Geforce GTX 980ti

 

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34 minutes ago, Bluestar said:

It appears to me that the PMDG fuel loader takes the number of pounds that the user attempts to input, converts that number to the nearest gallon and displays that gallon figure in pounds.  I have never seen a fuel tank capacity that was rated in pounds, it was always in gallons.  

You wouldn't have a fuel tank capacity rated in pounds because the total weight of the fuel would change based on the density of the fuel.

28 minutes ago, Bluestar said:

Volume of liquids is in gallons.  The number of gallons a fuel tank will hold will change daily based on the temperature of the fuel. 

Yes, I am aware that the volume of liquids is in gallons, but you don't get that information in the fuel loading page in the FMC. The PMDG fuel loader only allows you to enter a weight for the fuel. According to the Boeing documentation I have here, the Boeing 747-400 has a fuel capacity of 57,285 gallons. Assuming a fuel density of 6.7 gallons, this would put your fuel weight at 383,810 pounds. 248,000 pounds is nowhere near 383,810 pounds, as that's only 37,015 gallons. My point being, even with the PMDG Boeing 747-400 taking fuel density into account, which would affect the weight of the fuel that could be loaded, this should NOT be an issue when you are nowhere near close to hitting the limits of the fuel tanks. At the low extreme of a fuel density of 6.30, 57,285 gallons of fuel would translate to 360,896 pounds. If you tried loading any more than that weight at that fuel density, it wouldn't let you because you've already maxed the fuel tanks out volume wise. But 248,000 pounds is nowhere near close to that 360,896 pounds, so why it only loads 230,000 pounds at that fuel density is beyond me. That's the point I'm trying to get at. I don't understand why this got so complex in the first place.


Captain Kevin

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Air Kevin 124 heavy, wind calm, runway 4 left, cleared for take-off.

Live streams of my flights here.

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I just loaded the 747-400F in the Atlas N475MC livery. I initially set my payload to zero, (ZFW 364,000), and requested 248,000 pounds of fuel at standard density of 6.7 lbs/gal, and it loaded 247,998 - just two pounds shy.

I then set payload to MAX, which gave a ZFW of 610,000. I thought perhaps it would prevent loading an amount of fuel that would put the aircraft over MTOW. But, when I requested 248,000 pounds it again happily loaded 247,998, putting me 8000 pounds over the MTOW of 850,000 pounds. (I first set the fuel load back to 40,000 pounds before increasing the payload to MAX).

Tried it again with fuel density set to 6.3, and got 247,992

This is with the .9019 update on P3D 4.3 running on Win 10 Pro


Jim Barrett

Licensed Airframe & Powerplant Mechanic, Avionics, Electrical & Air Data Systems Specialist. Qualified on: Falcon 900, CRJ-200, Dornier 328-100, Hawker 850XP and 1000, Lear 35, 45, 55 and 60, Gulfstream IV and 550, Embraer 135, Beech Premiere and 400A, MD-80.

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2 hours ago, Captain Kevin said:

You wouldn't have a fuel tank capacity rated in pounds because the total weight of the fuel would change based on the density of the fuel.

Yes, I am aware that the volume of liquids is in gallons, but you don't get that information in the fuel loading page in the FMC. The PMDG fuel loader only allows you to enter a weight for the fuel. According to the Boeing documentation I have here, the Boeing 747-400 has a fuel capacity of 57,285 gallons. Assuming a fuel density of 6.7 gallons, this would put your fuel weight at 383,810 pounds. 248,000 pounds is nowhere near 383,810 pounds, as that's only 37,015 gallons. My point being, even with the PMDG Boeing 747-400 taking fuel density into account, which would affect the weight of the fuel that could be loaded, this should NOT be an issue when you are nowhere near close to hitting the limits of the fuel tanks. At the low extreme of a fuel density of 6.30, 57,285 gallons of fuel would translate to 360,896 pounds. If you tried loading any more than that weight at that fuel density, it wouldn't let you because you've already maxed the fuel tanks out volume wise. But 248,000 pounds is nowhere near close to that 360,896 pounds, so why it only loads 230,000 pounds at that fuel density is beyond me. That's the point I'm trying to get at. I don't understand why this got so complex in the first place.

I noticed today in the 747 when adding an airport in the fix page, I couldn't set the ring to 540nm. Is this really how it is or is it on my side? I cant set a range higher than 510nm, I usually put about 600-800nm for ETP points

Edited by captainsazzman

Flying Tigers Group

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4 hours ago, JRBarrett said:

I just loaded the 747-400F in the Atlas N475MC livery. I initially set my payload to zero, (ZFW 364,000), and requested 248,000 pounds of fuel at standard density of 6.7 lbs/gal, and it loaded 247,998 - just two pounds shy.

I then set payload to MAX, which gave a ZFW of 610,000. I thought perhaps it would prevent loading an amount of fuel that would put the aircraft over MTOW. But, when I requested 248,000 pounds it again happily loaded 247,998, putting me 8000 pounds over the MTOW of 850,000 pounds. (I first set the fuel load back to 40,000 pounds before increasing the payload to MAX).

Tried it again with fuel density set to 6.3, and got 247,992

This is with the .9019 update on P3D 4.3 running on Win 10 Pro

I tried it just now with a freighter, as I was using the passenger variants before, and I note no difference on my end. The only other difference is that you're running P3D and I'm not, because I don't have access to my computer at home, and this laptop only has FSX on it. When I get home at the end of the month, I'll have to investigate this on the other computer.


Captain Kevin

nGsKmfi.jpg

Air Kevin 124 heavy, wind calm, runway 4 left, cleared for take-off.

Live streams of my flights here.

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On 9/30/2018 at 12:05 AM, rsrandazzo said:

- 0007244: [General - Unsure] Number of passengers in PAYLOAD page change when fuel is set (mfrantzeskakis) - resolved.

 

I have not yet purchased/installed the 747-8 extension. The above issue is also present in the 747-400 - it was not there before 747-8 release and 747-400 updates. According to OC all is up-to-date.

Edited by Nemo

- Harry 

i9-12900K (12 Cores, 16+8 Threads, max 5.2 GHz, Aorus X 360 AIO H20, ASUS Z690 ROG Strix F), 32 GB RAM (DDR5 5200, CAS 38), RTX 3090 (Alpacool Eiswolf 360 AIO H2O).  Windows 11 Pro (1TB M.2 SSD C drive).  MSFS 2020 (MS Store, installed on C, MSFS Content on seperate 2TB M.2 SSD).   P3Dv5.3 (1TB M.2 SSD).

 

 

 

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1 hour ago, Nemo said:

I have not yet purchased/installed the 747-8 extension. The above issue is also present in the 747-400 - it was not there before 747-8 release and 747-400 updates. According to OC all is up-to-date.

In the release of the 747/748 there was a chnage on how the passengers would load. In these releases we make sure the passengers are correctly redistributed so the CG is always in limits. Load fule first and then passengers and you should be all set.


Chris Makris

PLEASE NOTE PMDG HAS DEPARTED AVSIM

You can find us at http://forum.pmdg.com

 

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