Andy Ross wrote
> Sent: 25 July 2004 21:07
> To: FlightGear developers discussions
> Subject: Re: [Flightgear-devel] Tried the Spitfire
>
> Vivian Meazza wrote:
> > I'm just working on the fuel gauge for the Spitfire, when I
> > ralised that I haven't modeled the fuel system correctly. At
> > present both tanks feed into the engine. What should happen is
> > that the upper tank feeds the lower tank which feeds the
> > engine. Is there any built-in way of doing this?
>
> One way to do this is to always make sure the lower tank is
> selected, and the uper one is not. Then have a Nasal timer fire
> at some sane frequency (mayby 5Hz) or whatnot that takes fuel out
> of the top tank and adds it to the bottom one according to the
> current pump configuration.
>
> It's not hard, really. You can look at the existing fuel.nas
> code for examples. The only gotcha I can think of is that the
> frame rate isn't constant: you want to use the time-elapsed
> property to calculate the amount of fuel to transfer, instead of
> assuming a constant amount per iteration.
>
Thanks Andy. I have already put together a Nasal script, using fuel.nas as a
model. It wasn't hard, once I had figured out how to make it re-iterate.
Nasal is a delight to use: doing exactly what we want.
The script tries to model the fuel system. Both tanks are connected to the
engine, and there is an open pipe connecting them, so fuel is transferred
from the upper to the lower whenever there is room in the latter until the
former is empty. So good so far - that bit works. The gotcha is that the
engine stops when either tank is empty, rather than when there is no fuel in
any tank. I can't see a way around that without tinkering with the logic of
fuel.nas. That said, the logic of fuel does seem a little odd. Have I got my
analysis of the logic wrong? Where is "kill-when-empty" set? I can easily
adjust fuel.nas to work for the Spitfire, but of course I don't want to rot
up any other model. How to proceed?
Thanks again.
Regards,
Vivian
> http://mail.flightgear.org/mailman/listinfo/flightgear-devel
_______________________________________________
Flightgear-devel mailing list
[EMAIL PROTECTED]
http://mail.flightgear.org/mailman/listinfo/flightgear-devel
