Does anyone ever put fuel in the wings?

[linuxgurugamer]

16 minutes ago, Snark said:

Feel free to take it lock-stock-and-barrel, to whatever degree you like.  I originally posted this waaaay back a couple of years ago when someone was asking about "how to do this thing", and just from rummaging around I think a fair number of folks have posted similar things since then (not sure if they took what I posted and built on it, or just came up with the idea independently).

In any case, I think this qualifies as an idea that's "out there" in public nowadays, so I don't think you need to worry about stepping on anyone's toes. 

Huh.  That's a thing?  Have never seen anything like that in the stock game.

If it's a modded thing, I suppose one could always extend the patch to cover it.  Though, is it something that a part would add to ModuleLiftingSurface, or have instead of it?  If it's an "instead" thing, would that not automatically be taken care of?

Not stock, it's a mod that I wrote:

The mod is a module added to a wing by a modder.  To see an example, look at SXT, there is a retractable wing in there.

Which is why I think you would have to exclude it, otherwise you would end up  with a collapsible wing with fuel inside, not a great idea

[justmeman117]

On 7/17/2018 at 7:16 AM, wumpus said:

My understanding is the whole point of putting fuel in the wings (IRL anyway) is that it *doesn't* alter the CoM.  Since the Center of Lift is presumably somewhere on the wing, draining the wings fuel doesn't change the CoM.  The other thing is that since the wings carry the plane, it makes the most structural sense to put the heavy fuel in the wings to avoid any structural issues: of course this leads to weird "wing wheels" in cases like the B-52 as this is only true *after* takeoff.

I work on a 707 variant for a living. Changing fuel levels in the wing tanks of aircraft will alter the COM, though not as much as forward and aft body tanks. Since the wings are swept back, the outboard tanks tend to be behind the COM, and the inboard tanks in front.

Since the 707 has 4 main wing tanks, each corresponding to one engine, all 4 tend to drain at nearly equal rates however.

You are correct that having weight in the wings helps with the structure though. Having all the weight in the fuselage and all the lift in the wings could conceivably cause an aircraft to fold if poorly designed. That being said, I think the biggest motivator behind wing tanks is that wings constitute a very large, mostly empty volume that on most aircraft is utterly useless for traditional cargo due to its flat shape. Fuel however, being a liquid, fills its storage container regardless of its shape. And the more of it you can put in the wings, the less of it you have to put in the fuselage, which is a volume better suited to solid cargo. So storing a fluid like fuel in the wings is probably the best use of that empty space.

 

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Personally, I always fill up the wing tanks. A tank that isn't being used to store fuel is wasted empty mass.

[linuxgurugamer]

Just an FYI for anyone using this patch.  It's broken in 1.11 because the models for the EVA kerbals no longer has Monopropellant.

The following is a working update, I left in the old line commented out, so you can see the change.  It is safe to put this into older installs as well:

// From @snark:
// https://forum.kerbalspaceprogram.com/index.php?/topic/176789-does-anyone-ever-put-fuel-in-the-wings/&do=findComment&comment=3420897
// Updated for KSP 1.11, kerbalEVA* had monoprop resource prior to 1.11, in 1.11, they do not, and this patch broke as a result
@PART[*]:HAS[~name[kerbalEVA*],@MODULE[ModuleLiftingSurface],!MODULE[RetractableLiftingSurface],!MODULE[ModuleCommand],!RESOURCE[*]]
//@PART[*]:HAS[@MODULE[ModuleLiftingSurface],!MODULE[RetractableLiftingSurface],!MODULE[ModuleCommand],!RESOURCE[*]]
{
	@description ^= :(.)$:$0 New and improved model now has liquid fuel.:
	RESOURCE
	{
		name = LiquidFuel
		amount = 0
		maxAmount = #$../mass$
		@maxAmount *= 500
	}
}

 

Edited December 18, 2020 by linuxgurugamer

[Beetlecat]

On 12/18/2020 at 3:58 AM, linuxgurugamer said:

Just an FYI for anyone using this patch.  It's broken in 1.11 because the models for the EVA kerbals no longer has Monopropellant.

The following is a working update, I left in the old line commented out, so you can see the change.  It is safe to put this into older installs as well:

// From @snark:
// https://forum.kerbalspaceprogram.com/index.php?/topic/176789-does-anyone-ever-put-fuel-in-the-wings/&do=findComment&comment=3420897
// Updated for KSP 1.11, kerbalEVA* had monoprop resource prior to 1.11, in 1.11, they do not, and this patch broke as a result
@PART[*]:HAS[~name[kerbalEVA*],@MODULE[ModuleLiftingSurface],!MODULE[RetractableLiftingSurface],!MODULE[ModuleCommand],!RESOURCE[*]]
//@PART[*]:HAS[@MODULE[ModuleLiftingSurface],!MODULE[RetractableLiftingSurface],!MODULE[ModuleCommand],!RESOURCE[*]]
{
	@description ^= :(.)$:$0 New and improved model now has liquid fuel.:
	RESOURCE
	{
		name = LiquidFuel
		amount = 0
		maxAmount = #$../mass$
		@maxAmount *= 500
	}
}

 

Was just doing some new digging, looking for lower-frills fueled wings solutions after realizing there were issues with Modular Fuel Tanks / FuelWings and all of the nested Part Switch and Cryo Tanks, etc.  things I'm playing with at the moment.

This'll do the trick!

It seems clunky, but also adding a bunch of these after the [kerbalEVA*] filter can exclude the smaller winglets and fins that it doesn't quite make sense to have fueled:

~name[*Fin*],~name[*fin*],~name[*Winglet*],~name[*winglet*] -- I'm not quite sure if they can  be stacked in the same expression, or if there's a way to disregard case-sensitivity, but this seems to work!

Edited October 10, 2021 by Beetlecat