Number of questions about some offsets (SDK)

[Erups]

In the sdk i read that the multiple fuel pumps feature is a fs2000/fs2002 thing only. Is this confirmed? In fs2004 you can have only 1 fuel pump per plane?

Now in the SDK what does the "reciprocating" mean?

And what does the "number of fuel tanks used" offset do?

Like the 3888.

If you already use 3880 for selecting the feed, what's the meaning of 3888?

Thank you very much

[Pete Dowson]

In the sdk i read that the multiple fuel pumps feature is a fs2000/fs2002 thing only. Is this confirmed? In fs2004 you can have only 1 fuel pump per plane?

I doubt if the numbers of pumps decrease -- it is whether the data has been located in the innards of FS that dictates whether FSUIPC can offer it!

Is there an "Ok" in the "FS2004" column? If not then it hasn't been verified. Check it yourself and if works let me know and I'll add the "Ok". This is the way it works -- I simply cannot test every entry myself even if I did understand them all, which I don't.

If there is an "Ok" then it is Ok. That's what it means. There is also a column for FS2002 -- but of course some of the entries were added after FS2002 was released, so then you'd get the confirmation in the text. I simply haven't got time to edit all the text and say "FS2000/FS2002 only, but maybe also FS2004 when someone confirms that it works there too". Sorry. this was why the columns were added several years ago.

Now in the SDK what does the "reciprocating" mean?

I think it defines the type of engine. Maybe some engineers here can tell you, otherwise I'd neede to refer to a dictionary. Sorry.

And what does the "number of fuel tanks used" offset do?

Not sure, but it possibly tells you the number of fuel tanks in use or available on the current aircraft? Can you check this? If so then I'll add that explanation.

If you already use 3880 for selecting the feed, what's the meaning of 3888?

I would think that a fuel tank selector selects fuel tanks whilst the number of fuel tanks counts them, but I'm sure you could verify this or not by using FSInterrogate and experimenting.

Regards,

Pete

[vdkeybus]

Loc. 3888 reports the number of tanks the engine is draining fuel from. This is mostly 1, but if you select 'All' or 'None' as the fuel source in Loc. 3880, this number may be larger (2 or more) or even zero. Personally, I don't think this value is of much use.

Loc. 3880 selects the tank the engine is connected to. The source is as mentioned under Loc. 0AF8.

I myself am using the series of values at Loc. 3B98 to turn on and off separate fuel pumps per engine. If you want to model more than one booster pump per engine, you have to write code that ORs both fuel pump switches for that engine. FS apparently accepts only one value per engine.

A sidenote one fuel pumps and tanks: the existence and use of these tanks and pumps is entirely up to the flight model ! Some aircraft models may allow you to start happily without booster pumps. Additionally, selecting a tank that isn't defined in the model will starve the engine.

Finally, reciprocating means that the engine uses a piston which moves back and forth during operation (like a car engine). These engines run at low RPMs, allowing direct connection with a propeller.

This is opposed to jet (turbo) engines, which use only rotating fan disks. Thrust comes from accelerating the incoming air (several tens of kg per second) to extremely high speeds. In all modern airliner engines, an extra, large compressor disk also accelerates cold air around the engine (bypass, turbofan) for additional thrust and lower noise.

The high operating RPMs of jet engines make it impossible to connect a classical propeller to their shaft, unless a massive gearbox is used. In that case, we're talking about a turboprop.

FS requires the aircraft model designer to select one of the above three propulsion mechanisms: piston, jet (turbofan) or turboprop. You should use Loc. 0609 to check which engine values you can use for each model. Fuel selector and pump operation seems to be the same for all types.

Pete, all locations mentioned here were checked in FS2004.

J.

[Pete Dowson]

Pete, all locations mentioned here were checked in FS2004.

Thank you!

I will add some more explanatory text to the Guide, along the lines you have provided.

Thanks again,

Pete

[Erups]

Thank you both for your replies.

My questions arouse from experimenting with commercial products.

Values for various offsets are strange in such cases.

For example even if i'm on an airliner, i see the piston engine offsets be used.... :?

Anyway thank you for your info.

Best regards

Claudio

[Pete Dowson]

For example even if i'm on an airliner, i see the piston engine offsets be used.... :?

I'm not sure which ones you mean, but many of the labels used for variables in FS are derived from one type of simulation and just re-used for others when it seems applicable.

If you'd like to be rather more specific I can perhaps be more explicit.

For more information on the sorts of names and labels used in FS you could try getting the Panels SDK from the Microsoft website. You'll find the documentation on gauge making interesting (and confusing if you tend to like things rigidly compartmentalised). Also a browse through the Gauges.h header file is illustrative.

Regards,

Pete

[Erups]

Peter

i have tried a few times to dig into the panel sdk and gauge header file, but as you know it's not an easy reading, even with some programming knowledge on yous shoulders.

What i meant above is that when i have an airliner with jet engines, i often see that piston engine variables are also used.

That was my confusion.

Thanks

Claudio

[Pete Dowson]

i have tried a few times to dig into the panel sdk and gauge header file, but as you know it's not an easy reading, even with some programming knowledge on yous shoulders. ...

Yes, but it serves to show you what a problem I face when naming or describing the values I find. The ones you have been referring to are, I think, all directly derived by tracing them through from panel type values, through the PANELS.DLL into SIM1.DLL, which is the module which owns them and maintains them as private data. Unless folks find otherwise, all I can assume is that the way they are named in the Microsoft SDKs is somehow descriptive about what they do.

Not being an aircraft designer or even a user of any of these variables, I can only add to the Guide the information I can glean from things like SDKs and things folks tell me.

What i meant above is that when i have an airliner with jet engines, i often see that piston engine variables are also used.

That was my confusion.

Mine too. This is why I referred you to the SDKs so you could see the source of the confusion! :wink:

Regards,

Pete