Fuel management

[panzerd18]

I have tried to find the answer in the manual with no luck. Apologies if I have missed it somewhere in there.

 

My question is fuel management on the P-51D.

 

I understand the rear fuselage tank causes instability when filled up, and caused many inexperienced pilots deaths.

 

So my theory is, fuselage tank selected first, then drop tanks, then left/right wing tanks?

 

Firstly how do I know when to switch between the left and right external drop tanks? Did pilots switch after a predetermined time? Also are drop tanks run down until the engine starts to splutter as there is no way of knowing the fuel quantity remaining?

 

Also is the fuel booster pump left on, or can it be switched off after takeoff and only turned back on when switching tanks?

[Tiger4-2]

Most of the time the rear fuselage tank wasn't filled up. There's a special note in the manual where it says don't fill it up except under special order by the squadron commander. The reason being that the P51 already has incredible legs as is, and the extra 40 gallons and resulting instability isn't worth it unless you need every spare gallon.

 

If you do fill up the fuselage tank, select that first, then once it's empty switch to another tank.

 

If you're running drop tanks, use either the fuselage tank (if it's full) or one of the wing tanks for takeoff, then at 2000 feet switch to your drop tank. As far as knowing when your drop tanks are empty, the only real way is to look up the fuel burn per hour for your cruising speed, then calculate in minutes how long the fuel tank will last before being depleted.

 

Alternatively, the p51 retains enough fuel pressure to keep the engine running for a few seconds(albeit roughly) when the tank runs out, so if your quick, once it sputters you can switch it over real quick and restore normal operation. It helps to have a general idea of when to start thinking about switching it over though. That's where fuel burn per hour comes in.

 

As for booster pump, don't quote me but I'm pretty sure you leave it on when running drop tanks, then turn it off after switching to your wing tanks.

 

Sent from my SM-G973U using Tapatalk

[saburo_cz]

Micro-switches are inside Fuel Selector Valve and they swich On/Off booster pumps.

When external fuel tank is selected, no one booster pump is running.

Only booster pump in selected fuel tank, L/R wing or fuselage, runs.

[grafspee]

Drop tanks are pressurized by air provide from supercharger iirc.

[jamesgmills]

I'm not sure if it's modeled accurately to where this is necessary, but the manual (page 39) says to use the left fuel tank first:

 

Quote

The carburetor is of the fuel injection type with a separate idle cut-off device and is equipped with a vapor return line that extends to the left fuel tank. The vapor vent line may become a fuel return line if the needle valve in the vapor eliminator sticks in the open position. The left fuel tank should always be used first to ensure availability of space for any returning fuel.

 

Not sure if it's modeled, though, and I think Tiger-4-2 said all the rest pretty well.

[sjebens]

From the book Clean Sweep:

The Mustangs that arrived had been modified by VIII Technical Command when they arrived in England with an additional gas tank mounted immediately behind the pilot in the fuselage on the Center of Gravity that could carry an extra 90 gallons. When this was filled, pilots discovered that the airplane was slightly tail-heavy, which restricted maneuverability. Operating procedures were modified so that a pilot took off with gas fed from the wing tanks; once airborne he would switch to the cockpit tank to burn off that fuel before reaching enemy territory; when that was empty, he would switch to the drop tanks until either they were empty or the enemy was engaged. The fuselage tank was invaluable, since it provided sufficient range that the P-51 could reach any target in Germany with the combination of fuselage tank, drop tanks, and wing tanks.

[Rainbowgirl]

Use the clock in the cockpit to determine when to switch between left and right external tank. For example select left tank and let the engine feed from it for 15 minutes initially. Then select the right external and let the engine feed from it for 30 minutes, then just repeat every 30 mins until they get dry one by one. That`s one way to keep the plane balanced during long distance cruising with minimal use of aileron trim. 

Edited May 14, 2024 by Rainbowgirl

[felixx75]

https://youtu.be/6s93EFjGIKQ?si=EMIc0wi356qBcVlx @21:29