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Understanding the drop tanks.


statrekmike

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So, forgive me if this is a silly question but could someone explain how the drop tanks work in some detail, I know about the knob that you can turn to select the inboard, outboard or individual tanks but I it seems like I am still drawing fuel from my main tank when I have a set of inboard or outboard tanks engaged.

 

Is there something I am missing?

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Yes i have a same problem. I supose the drop tanks dont works in opebeta :(

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So, forgive me if this is a silly question but could someone explain how the drop tanks work in some detail, I know about the knob that you can turn to select the inboard, outboard or individual tanks but I it seems like I am still drawing fuel from my main tank when I have a set of inboard or outboard tanks engaged.

 

Is there something I am missing?

 

Check this link out, it might help. It's an F86E but its gotta be close.

 

http://aviationshoppe.com/manuals/f-86_flight_manual/f-86.html

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Updated link. http://aviationshoppe.com/f86-sabre-documents-manuals-a-62.html

 

Heres a manual for Milviz's F86F in FSX.....midway there is a page about the ext fuel console....worth a try if the 86e manual above doesnt cut it.

 

https://www.google.com/url?sa=t&source=web&rct=j&ei=o3TTU8O9DsK6igL0w4DAAw&url=http://www.milviz.com/filesfordownload/Milviz%2520F86%2520User%2520Guide.pdf&cd=3&ved=0CCAQFjAC&usg=AFQjCNEFuAfLCgcYFWppaUIQm-PSe2Ng8A


Edited by jarhead2b
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It just doesn't work currently.

 

According to the manual there is a drop tank fuel shutoff valve on the left aft console, currently that is absent. Its also unnecessary, when the valve is on drop tank fuel is forced into the forward fuselage tank before being consumed. Its only has one mode that consumes drop tanks first.

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It just doesn't work currently.

 

According to the manual there is a drop tank fuel shutoff valve on the left aft console, currently that is absent. Its also unnecessary, when the valve is on drop tank fuel is forced into the forward fuselage tank before being consumed. Its only has one mode that consumes drop tanks first.

 

It´s not a FUEL shutoff valve. It´s a engine bleedair valve used to pressurise the droptanks to force the fuel into the forward tank.

 

FinnJ

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We compared indicated fuel when we flew yesterday and after 10-20 minutes airborne we didn't see a big difference between those with and without droptanks.

 

Now this was just a simple observation between aircraft doing different things, bombing, take off and landings etc. But it seems to me that we couldn't get our A/C to draw fuel from the drop tanks.

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Seems we need a console like this

 

5mG1OVY.jpg

 

And this explains the usage

 

jWYnPRO.jpg

 

...like I said two posts up this thread.

 

FinnJ

i7-10700K 3.8-5.1Ghz, 32GB RAM, RTX 4070 12GB, 1 x 1 TB SSD, 2 x 2TB SSD2 TB,  1 x 2 TBHDD 7200 RPM, Win10 Home 64bit, Meta Quest 3.

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The system is designed this way.

If you have no external drop tanks, place the Drop tank selector in "All Tanks Off"

 

If you have external tanks yoiu have to place the selector on OUTBOARD ON & JETT or INBOARD ON & JETT.

 

If you carry both types, always use and drop first the OUTBOARD.

 

When you have selected one of the tanks what you do is to pressurize that tank so it feeds fusselage internal tank.

 

The way to know if your tanks are empty is:

 

The moment your drop tanks aer epmty, you will see how the main fuel gauge starts to show comsumption from the fuel total (While feeding from the tanks the internal tanks are supposed to be full so the fuel gauge shows full since it does not show drop tank contents)

 

In case you are flying with both OUTBOARD and INBOARD Tanks, as mentioned, first use the OUTBOARD. When those tanks are empty, you will have a light near the tank selector ON, so you you know that the OUTBOARD tank is empty.

The light only shows OUTBOARD empty tank. To know when the IMBOARD is empty as mentiones check when your main fuel gauge shows fuel comsumption. :thumbup:

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The system is designed this way.

If you have no external drop tanks, place the Drop tank selector in "All Tanks Off"

 

If you have external tanks yoiu have to place the selector on OUTBOARD ON & JETT or INBOARD ON & JETT.

 

If you carry both types, always use and drop first the OUTBOARD.

 

When you have selected one of the tanks what you do is to pressurize that tank so it feeds fusselage internal tank.

 

The way to know if your tanks are empty is:

 

The moment your drop tanks aer epmty, you will see how the main fuel gauge starts to show comsumption from the fuel total (While feeding from the tanks the internal tanks are supposed to be full so the fuel gauge shows full since it does not show drop tank contents)

 

In case you are flying with both OUTBOARD and INBOARD Tanks, as mentioned, first use the OUTBOARD. When those tanks are empty, you will have a light near the tank selector ON, so you you know that the OUTBOARD tank is empty.

The light only shows OUTBOARD empty tank. To know when the IMBOARD is empty as mentiones check when your main fuel gauge shows fuel comsumption. :thumbup:

 

 

How exactly do we pressurize the tank? I don't really see a control anywhere in the cockpit to do such a thing.

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Really Dude?

 

"Air pressure from the engines compressor section" = "Engine bleedair".

 

But no point keep debating - same meaning ;)

 

FinnJ

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  • 5 years later...

It seems to work.

~

 

4 drop tanks + full fuel.

 

-50 minutes at 95% throttle at low altitude, gauge steady at full 3000 lbs.

-OuBd tanks empty lamps goes on. gauge starts to drop.

-jettison outboard tanks, switch to inner drop tanks, gauge goes back to full 3000 lbs.

-experiment stop

 

This, I think, is how it's supposed to work by the original Flight Manual (page 1-20, 1-21 and diagram on page 1-24).

Fuel is always drawn from the lower forward fuselage double cell. All other tanks (including drop tanks) keeps filling the lower forward cell (yes, fuel is pressed up into forward upper double cell and drops by gravity when every other tank is empty).

 

Note (see manual), fuselage tank is split in 5 parts. A forward connected double cell on top of each other, an aft cell and one cell in each wing root. Forward (upper) cell is always kept topped up (20 gallon empty) for center of gravity purposes. This since version -25 and upwards (ie including DCS -35 version).

~

 

I did at first another test a 20000-40000 feet. It seemed to work differently at altitude but I may have fumbled it. No patience to redo it right now.


Edited by -0303-

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  • 5 months later...

Yes, this works - recently burned through all four underwings and landed on fumes on the internal tanks.

 

 

Remember, the inboard tanks don't have an indicator when they are empty. You can only tell they are empty by the internal fuel gauge starting to move.

 

 

IIRC gave ~2hrs flight time at mostly WOT.

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