Why do fuel tanks empty consecutively?

[pschlute 37]

Aileron trim can offset L/R fuel imbalance but most aircraft have a maximum differential that the manufacturer recommends, in the case of the 737 I think it is as low as 1,000 lbs.

 

Of course there is one aircraft that regularly crossed the atlantic at M 2.0 that would deliberately create a L/R imbalance so that excessive crosswind could be dealt with without the need for drag inducing elevon (it didn't have ailerons) trim.

[martinlest2 58]

If cargo has shifted in the hold then I agree, but pilots don't use aileron trim to correct lateral fuel weight imbalance (except in emergency), they use the crossfeeds to balance the weight of the fuel more or less evenly between the right and left side tanks...

 

Of course there is one aircraft that regularly crossed the atlantic at M 2.0 that would deliberately create a L/R imbalance so that excessive crosswind could be dealt with without the need for drag inducing elevon (it didn't have ailerons) trim.

Indeed! I remember its first commercial UK flight - it flew across my house (we lived near enough to Heathrow that we could hear the afterburner roar at take-off). Still very sadly missed (even if I could never afford to travel on it!!).

[vololiberista 205]

Work is progressing a pace on the final part of the Super VC10 manuel. With a fully functioning fuel panel, underwing uplift and the PO will also advise you of how many minutes left for jettisoning. Plus a fuel calculating spreadsheet with authentic loadsheet. What more could you ask for £0.00!

[martinlest2 58]

I hardly ever fly 'legacy aircraft', ones that are no longer in the skies (Concorde being a notable exception) but I should probably take a look at this plane. Though I am not really up for any steep learning curves right now! Where's the download link please?

[vololiberista 205]

I hardly ever fly 'legacy aircraft', ones that are no longer in the skies (Concorde being a notable exception) but I should probably take a look at this plane. Though I am not really up for any steep learning curves right now! Where's the download link please?

It's not as complex as Concorde. The main difference between it and modern a/c is that "you" are the FMC!

[Dave Morgan 68]

Hi.

 

Anyone here fly Captain Sim's C-130? I've noticed it has a life-saving fuel flow bug where if the centre crossfeed valve is switched on, each engine takes fuel from the un-emptiable and supposedly unusable 'flow' tank (presumably the fuel in the virtual pipework). When I'm reaching the point of running on fumes, turn the centre crossfeed on, turn off each fuel pump and fly for ever...

 

(Handy for empirically determining V speeds as the plane's weight doesn't change).

 

Best regards,

D

[Christopher Low 5,335]

Fuel in my A2A Piper Comanche 250 appears to be drawn from both tanks at the same time.

[Alpha Floor 237]

Pumps are not all the same, engines are not all the same. So there will be differences, slight of course (or intended to be slight at least).

 

I'm surprised to hear that happens in any default aircraft. I guess the engines of the default 737 are "exactly" the same, its pumps (i don't think it models any pumps, but rather fuel flow) will be exactly the same for each engine and so on.

 

Interesting thread, thanks for your comments vololiberista!

[Alpha Floor 237]

Thanks for the comment Mitch!

 

 

 

No aviation equipment that I know of operates exactly 100% the same.

 

Yeah well, but that's what I implied to say

 

When I said that the default 737 should be "perfectly" balanced, I referred to the simulator FSX or FS9 737

 

I'm sorry if I still don't understand your point

[vololiberista 205]

All "generic default" a/c either in FS9/FSX or P3D work in exactly the same manner. Particularly jet a/c. The airfiles are pretty much identical when it comes to fuel and engine management. You might get a couple of instances where the number of tanks might differ but the way the sims control the fuel flow is the same for each a/c.

A good developer will either write their own fuel flow system in C++ or use Doug Dawson's fuel dump gauge (as I do). His gauge allows for genuine fuel uplift i.e. not just typing in a number representing fuel needed but actually filling the tanks in real time. With it I can transfer fuel between tanks at a specific rate even gravity feed. And of course dump fuel!

Unfortunately they exist those that don't bother and in effect make you pay for a default aircraft!

Does your engine surge on start-up? If so you have default fuel settings across the board.

[edetroit 933]

A good developer will either write their own fuel flow

 

An even "better" developer would have the different fuel tanks placed in the correct positions in the aircraft cfg.... Not just one tank.

 

It is also very unlikely that all engines will have the same performance...one could easily make them perform slight differently (note to self) ?

 

That would make the multi engine experience far more interesting ....if you had more than 1 tank.

[A32xx 129]

 

 

It is also very unlikely that all engines will have the same performance...one could easily make them perform slight differently (note to self)

 

That certainly would be nice! But how could it be done - in the aircraft .cfg and .air files there is only one engine spec with a multiplier (number_of_engines=) meaning all engines are identical clones?