[NO BUG]auto-start procedure missing fuel-pump on and fuel tank pressure on.

[D4n]

those 2 are missing, left in "off" after autostart is finished.

[Mud]

- Fuel pressure should not be turned on unless the fuel pressure warning light comes on during flight.

 

- Fuel pump may be turned on once the engine is running, but this is not required unless you climb to high altitudes.

[D4n]

- Fuel pressure should not be turned on unless the fuel pressure warning light comes on during flight.

 

Ah true, I assumed the fuel pressure light to come on at high altitude, as sb. mentioned to switch it on in high altitude flight.

So then, yes, only fuel pump switch should be set to on on autostart. (it doesn't hurt to switch it on and only fly low level, right? And otherwise, new players will get confused why their engine shuts down at high altitude.)

[Mud]

Indeed, as far as I know there is no harm in turning the fuel pump switch on, as long as the engine is running OR the mixture is in the OFF position (with engine off).

[D4n]

Still not fixed

[D4n]

Over 4 months passed....

[kreisch]

Because this is not a bug, you never fly with the electrical fuel pump in 'always on'.

Common usage is to engage the electrical pump during starts, landings and the especially performance critical parts of the flight - basic transit is not critical.

 

Gesendet von meinem VOG-L29 mit Tapatalk

[D4n]

"basic transit" not critical? "basic transit" means from for example one altitude to another or not? And a steep climb is a performance critical part of flight, and there you "transit" from a lower to a higher altitude...

[kreisch]

I recommend reading stuff about flying in general.

In propeller driven planes you do not have the electrical fuel pump always on and no, I said "transit" (flying from A to B) and not "during climbs" (I'm not aware that it is turned on during climbs, but could be, don't know honestly!).

 

Do you have a source stating it otherwise?

 

E.g. https://www.aopa.org/news-and-media/all-news/2020/january/flight-training-magazine/ol-how-it-works-fuel-system

".....here should be an electrically powered pump for engine start and use as a backup. You’ll also see a fuel pressure gauge, so you can know that the pumps are working properly."

 

Or you take a look into a german book "Motorflug kompakt: Das Grundwissen zur Privatpilotenlizenz", which also explains, that the electrical pump is a backup system.

You do not have it "always on", because in this case you would never experience a fault in your mechanical pump - and then you'll enter the world of problems if your electrical (backup) pump fails.

You only set your electrical fuel pump to "on" if your mechanical one fails OR you are in critical phases like takeoff or landing, when a failing pump is too dangerous.

 

 

Edit: HA! you got me!

I was wondering if the spitfire is something special, might be it is.

 

The checklist of a PA-28 (Piper Archer) says "Turn OFF Electric fuel pump at desired altitude". This is common to other, current planes.

BUT the manual of the spitfire says (page 17 (Use of the booster pump(s) The main tanks booster pump should be switched ON for take-off and landing and at all times when these tanks are in use in flight".

 

So, yes, after reading this it seem's you are right - but this is not a general statement.

Why the spitfire has a different handling, I don't know, but it seems to be the case!

 

Learned something new ;)

 

Btw: It is never a good idea to run a pump on a dry system, this will (sooner or later) kill it's mechanics.

 

BR,

kreisch

Edited August 29, 2020 by kreisch

[D4n]

aaah, I mixed "transit" with "trasition", or, I assumed you shortened "transition" to "transit".

 

kreisch, did you read all previous posts, are you aware that in Spitfire, the fuel-pump must be turned on when climbing to a specific altitude, to avoid engine cutout?

Then the logical conclusion would be to include fuel-pump in autostart, as we don't want any new DCS Spitfire player to experience a very frustrating engine cutout during a high-altitude climb...

[Goblin]

I had a look in the pilots notes...

In the section covering handling, the start-up sequence says the following, after the engine is running:

 

“Check that the fuel pressure warning light does not come on then switch ON the main tanks booster pump (if fitted).“

 

What does that mean? Switch on the pump only if the warning light comes on, or do it anyway?

 

The pre-takeoff checklist notes that the Main tanks booster pump should be on for takeoff.

There is no note saying it should be shut off after take off. Nor is there any mention of the pump being used for climbing.

 

So, I’m not sure the pump should be on after start-up, but it should be on for takeoff and not shut off again.

There is, however, a note in the landing checklist that the booster pump should be on.

Nothing that I can find about shutting it off...

[grafspee]

Fuel pump when On is pressurizing whole fuel system and helps drain tanks.

Engine is equipped with mechanically driven fuel pump, but this pump is mounted directly on engine.

This pump alone in some scenarios may not be sufficient.

For example in rapid climb when fuel temp is relatively high but outside pressure is droping fast, in fuel lines, fuel vapor will appear disrupting fuel flow and this will end up with engine cut off.

Similar things may happen when performing some extreme maneuvers(neutral or negative G).

Other way is to pull the pressurization handle, which will release high pressure in to the tank from high pressure reservoir, this solution makes exactly the same, what electric fuel pump does.

but there is one cone of this way, when your fuel tank get punctured or is simply not sealed 100% you will lose high pressure eventual or when leak is below fuel level you will went fuel out of the plane which is not good.

After you reach your cursing alt and sufficient time will pas to fuel to cool down pilot probably can turn off electric fuel pump just to save wear on this item.

So first question come in to mind, what was solution for early spitfires which were't equipped with electric fuel pumps or pressurization of fuel tank.

Answer is simply, early spitfires couldn't be flown in this way, w/o risking of engine cut out.