The A2A Simulations Community

Hi all,

I am using FSX Acceleration, and the Accusim Spitfire with Accusim core update 1.2 installed.
Flying the Spitfire Mk.II with constant speed propeeler, 87 octane fuel, normal oil, set 5 gallons of fuel in the bottom tank only, mixture set to rich, engine RPM to 70%.
I started a short flight with fast climb in order to verify a problem that I noticed yesterday in a longer flight: when the engine is about to run out of fuel, instead of coughing and progressively loosing power, it keeps sounding like if it were running smoothly, but the power (plane acceleration) is totally gone, just like if the engine was dead already.

As a consequence, even if the engine gauges are still showing +4 boost and 2700 RPM steady, I have to stop the climb because the speed drops very fast below the 120 knots. I have to dive at -2000 feet/minute to maintain a poor 110 knots airspeed. Engine still running as if nothing occured. After more or less 30 seconds (didn't really pay attention), the engine finally starts coughing and eventually stops running after 15 to 20 seconds, without any influence on the plane speed (since power has gone away one minute before already).

As I was climbing in a circle over my airfield, I was able to land after a long dive from 9000 feet altitude. It was suprising how much drag the propeeller was generating, I had to extend the gears and flaps at the very last moment, something like 10 seconds before landing...

Another stange thing occured after I refilled the tanks (and cleaned the plugs): upon engine starting, the plane made a "jump" forward, as if maximum power was applied, even though the engine was at idle RPM and throttle was at 15-20% (regular low throttle for engine startup, nothing special).

Is anybody experiencing the same problems ?

Ah, someone sees what i see at last, im not mad! Thats an encouraging thought, wouldn't you say ?

It has been reported some time ago, for now no work-around is present, the engine stops producing thrust if you empty your tanks to the point, where in the accusim manager it shows 0% fuel, but the simulated fuel in ducts holds the engine up and running for some time.... dispite not producing any physical force.

Try not to fly on vapors anymore, you've been warned.

Same feeling here, good to see it's not a problem specific to my computer. Thanks for your feedback

Well then I suppose it's one of these small Accusim flaws. Nothing dramatic but next time I'll think about approaching the airport at high altitude for a final dive each time the tanks will be too close from the end. No more low altitude approaches for me, not unless the tank has at least 5 gallons left

Yeah, that's been reported before: the simulation react differently to fuel pressure dropping due to empty fuel tank, and fuel pressure dropping due to closed fuel cocks. With closed fuel cocks, it runs perfectly normally for a while, then gradually loses power and starts coughing as mixture leans out. If you run out of fuel from the tank: zero horsepower before even seeing any drop of fuel pressure. You can even run the engine 3000rpm +12psi on the ground, without brakes/chocks applied, without applying elevator control or anyone holding the tail, and it just won't move an inch or nose-over. Or if you run out of fuel on approach, you suddenly drop like a brick while your engine keeps purring like a kitten.

The solution is simple: go to FSX setting and enable unlimited fuel. Accusim will model fuel run-out accurately on Spitfire. The bad thing however is, non-modular Accusim (not to mention stock FSX craft) require limited fuel for engines to die out of fuel starvation. For example B-17 will run even after fuel tanks are empty if you configure FSX to model fuel run-out properly for Spitfire. You need to change this setting each time you change the plane you want to fly... or just not run out of fuel.

Even though I know the solution to the bug (which is actually FSX feature) I don't bother changing the setting for times when I fly Spitfire. I don't run out of fuel with Spitfire that often. :p
It's more important to have fuel run-out modeling for multi-engined, multi-tank aircraft like B-17 and B-377 since they actually have fuel management. And I like bad fuel management to have bad repercussions. Therefore I just have to deal with Spitfire's sudden power loss on fuel run-out.

i have the same problem as well.

I also have a fuel leak that i can't fix. Engine is of i leave flight sim running and walk away to have dinner or something like that, and when i come back there's no fuel.

_________________

Have you checked your maintenance hangar for leaks first ? It doesn't sound like a problem listed here.


The 1.3 Patch fixed this issue. The thread should be labelled as "Fixed" from now on.

Fixed label added

_________________
A2A Facebook for news live to your social media newsfeed
A2A Youtube because a video can say a thousand screenshots,..
My twitter for my own twitter and random A2A insights