Can’t seem to be able to use the bomb bays tanks.

MrTchou

Hello everyone,
I try to setup my plane for maximum range, but so far i’m struggling with some of the aspects of it : i setup the plane with 3 bomb bay tanks, and when i’m on climb i switch the fuel selector from main to bomb bay on the retractable console. However, the plane doesn’t seem to use those tanks since when I check on the fuel&weight menu in xplane, those external tanks seem to be still completely full.
Anyone could provide a complete how-to in this regard ?

Martyn

The way they're simplified is that they will transfer their mass into the Group 2 and Group 3 fuel tanks, as long as the appropriate valves are open. So to use the bomb bay tanks, first make sure one or more is selected in the weapons selector pop-up. Then go down to the bomb bay fuel panel between the pilot seats. Turn on the bomb bay fuel pump switches, then open the left and right valves (labeled "Bomb Bay / Main"); left goes to Group 2, right goes to Group 3. This will cause the bomb bay tanks to begin transferring their fuel into the Group 2 and Group 3 tanks. You can see the bomb bay tank quantities decreasing by watching the dataref "sim/weapons/total_weapon_mass_now[0]" , [1], and [2]. And you'll be able to see the fuel quantities in the Group 2 and 3 tanks increasing. If you have 3 cylinder tanks installed, the middle tank is hooked up to the rear pumps, with the rear cylinder tank.

McTrying

@Martyn said in Can’t seem to be able to use the bomb bays tanks.:

You can see the bomb bay tank quantities decreasing by watching the dataref "sim/weapons/total_weapon_mass_now[0]" , [1], and [2].

And how is the average X-Plane simmer expected to know how to access 'dataref "sim/weapons/total_weapon_mass_now[0]" , [1], and [2].' ???

And question...
Should any fuel remaining also be readable by looking at the current state under the X-Plane tab/Flight/Edit Weight & Balance/External Fuel Tank 1,2,and 3???

As for transfer of Bomb bay fuel to tank groups 2 and 3 only...this is totally unrealistic and not acceptable given the instructions in the Just Flight Vulcan operation manual....

Quote "Provision is made for carrying either saddle-shaped or cylindrical fuel tanks in the bomb bay. Fuel from these
tanks passes into the main system through two delivery lines to each side of a centre cross-feed cock."

Quote "Bomb bay fuel tanks
Use the fuel in the bomb bay tanks as soon as possible after take-off. Before selecting the bomb bay tanks, the
main tank AUTO/MANUAL switches must be set to AUTO and all booster pumps must be ON.
When established in the climb:

Open the wing cross-feed cocks.
Set both pump switches ON for each tank in use.
Set both BOMB-BAY/MAIN switches to BOMB-BAY.
Check that the bomb bay magnetic indicators change to white when the pump switches are set to ON
and then revert to black as the pressure builds up.
When the magnetic indicators show white, or the tank contents have fallen to 150lb, set the BOMB-BAY/
MAIN switches to MAIN.
Switch OFF the booster pumps and close the wing cross-feed cocks."

NOTE: Bomb Bay Tank Fuel is fed to Main Fuel Crossfeed Gallery, and NOT to any Tank Group!!
McTrying

NoJoe

Hi, I'm one of the developers of the Vulcan.

@McTrying said in Can’t seem to be able to use the bomb bays tanks.:

Should any fuel remaining also be readable by looking at the current state under the X-Plane tab/Flight/Edit Weight & Balance/External Fuel Tank 1,2,and 3???

Unfortunately no, this appears to be a limitation in X-Plane's weight and balance UI. It seems to load the fuel values before the airplane itself has loaded, so the external fuel tank quantities that are showing in X-Plane's UI don't actually coincide with the plugin-controlled custom logic.

The aircraft fuel tank quantities will display correctly (and will correctly update as you fly), but the "External Fuel Tank" quantities won't correctly update. I don't know of a way to work around this, as this is an X-Plane limitation. For preflight planning you can set those sliders to the actual tank contents in order to be able to read the correct maximum weight. (0 lbs when no bomb bay tank is installed, 5,750 lbs for a full saddle tank, and 7,960 for a full cylindrical tank).

However, I took a look at the fuel code for the bomb bay fuel transfer and was able to change the behavior so the bomb bay tanks will now supply to fuel all 4 tank groups (not just groups 2 and 3). I would guess this change will make it into v1.2 of the Vulcan. I hope this helps!

Best regards,
Joseph

McTrying

Thank you for your reply @NoJoe

Glad you have found a way to share the Bomb Bay tank fuel with all 4 tank groups.
I am working on thoughts....
Re: workaround Bomb bay Fuel weight possibilities, and will share those thoughts in a less 'Public Way' than here in this forum.
McTrying