External tanks & the English cockpit...

[BeachAV8R]

So this was a bit of a head scratcher for me for the last few hours - and I think I've got it figured out (with the sharp eyes of Einstein EP keeping me straight)..but I'm just wondering if someone can explain why the annunciators are labeled this way.

 

So the normal order of operations when sporting about with 3 external fuel tanks is:

 

External wing tanks - empty

External ventral tank - empty

Internal fuel

 

So as the wing tanks get near empty, the annunciator comes on behind the stick on the center panel: FUEL PODS EMPTY A. It seems odd to me that this is located right next to the CENTER FUEL TANK annunciator that lets you know you have a CENTER/VENTRAL tank mounted. In my initial dealings with the airplane I just assumed that when the FUEL PODS EMPTY A light came on it meant that the VENTRAL tank was exhausted.

 

Why did I think this? Well, because the other annunciator (on the right annunciator panel) says: FUEL PODS EMPTY W. I took the "W" to mean "WINGS" right? Wrong. W and the plural "PODS" apparently means, V (Wentral in Russian I guess) and singular.

 

Confused? Yeah - so was I. The manual apparently has it right though..but there is some room for confusion for those of us using the English cockpit.

 

 

 

My suggestion would be to have the two lights read:

 

FUEL POD

CTR EMPTY

 

or

 

FUEL POD

VTRL EMPTY

 

and the other one read

 

WING PODS

EMPTY

 

Or something less apt to get confused.

 

Unless I was the only one.

 

In which case. Carry on.

 

I'll learn Cyrillic! :thumbup:

 

By the way - did LN implement the loss of pneumatic air in a recent patch..because I think I lost air pressure when I was doing a lot of braking while doing some engine runs to test some fuel flow stuff...

 

:music_whistling:

 

Love this module..!

 

BeachAV8R

Edited March 15, 2015 by BeachAV8R

[BeachAV8R]

Einstein and I have been dorking around with this still tonight - and we both reached the same conclusion that the 3 external tanks are at least somewhat being drawn down simultaneously. After getting the lights for the wing tanks, two minutes later (at military power) you get the light for the ventral tank. No way you are burning through 900L at that power setting in two minutes...

[xxJohnxx]

Einstein and I have been dorking around with this still tonight - and we both reached the same conclusion that the 3 external tanks are at least somewhat being drawn down simultaneously. After getting the lights for the wing tanks, two minutes later (at military power) you get the light for the ventral tank. No way you are burning through 900L at that power setting in two minutes...

 

Hmm, this is interesting. I remember I did some tests on that a while ago and it seemed to work correctly.

Didn't really pay attention since the latest patches though, but I will go and have a look.

[xxJohnxx]

Can definitely confirm this.

 

In the attached track I took off with full burners (not emergency though) and kept on a constant altitude.

The "external-wingtanks" empty light started flickering at around 3200l remaining, 5:50 minutes after setting take-off power.

It illuminated constantly at around 3000l remaining, at 6:30 after take-off power was set.

 

The "external-central" fuel tank light came on at 2900l, at about 7:00 minutes after take-off.

 

All the external tanks seemed to feed the engine at the same time. The 900l central-tank seemed to feed at about twice the rate of each individual 490l wing-tank.

Not sure how this would change with the 490l central-tank.

MiG-21Fuel.trk

[BeachAV8R]

Thanks for the confirmation xxJohnxx - that mirrors what we were seeing. Not a huge problem at all. In a scrap, I don't know that too many people that jettison only the wings or only the belly tank..but I'm sure someone does it. LOL..

 

BeachAV8R

[JorgeIII]

I recommend you read / check the manual for fuel light indicators sequence.

 

If I remember correctly the 21 has 2950L in internal tanks and it can carry 800L or 490L external ventral (central) tank and/or 900L in 2x450l wing tanks.

 

The mig has 2 remaining fuel indicators:

 

1) the round one (yellow) witch uses a manually entered total fuel value as initial reference (done by ground crew) and then takes in account used fuel to calculate remaining fuel. It can have errors, for example if you release and external tank before time it will indicate more fuel than you really have. Fuel is indicated in Liters x 1000.

 

2) The light system, linked with real remaining fuel in internal tanks.

 

I usually carry:

 

Internal tank: 2950L

 

or

 

Internal 2950L + Ventral 800L tank:3750L Total.Tank is released when ventral tank empty light goes on continuously. You will read about 2950L remaining in yellow fuel instrument if it's working ok.

 

or

 

Internal 2950L + ventral 800L ext. tank + 2 450L ext. tanks. Total fuel 4650L. Wing tanks will empty first. No light will go on. I release the wing tanks when I have less than 3750L (3650L to be safe).

 

The logic for the wing tanks light might be wrong. Ventral tank light works perfect AFIK.

Edited March 18, 2015 by JorgeIII

[Flagrum]

There is definately something off with the tanks.

 

I run one brief test: hot start, airborne, 2x490l + 1x800l + 2850l

 

Issue 1: the fuel gauge was set to 2850l, not taking any of the ext. tanks into account

 

So I adjusted it to (about) 4000-something. Flew constantly with full AFB2

 

"Wing tanks empty" came on after about 1000l (as expected)

Very shortly after (well, due to full AFB2) the "ventral empty" came on (as you already reported)

 

Then I got a flame out - while flying low and level (ACFS recovery mode). Strange, but whatever ... perhaps due to time accelleration?

Then some minutes later, next flame out - but this time I could not restart the engine. Hrm, fuel left: ~ 2000-ish liters. Wait ... that was about the amout I adjusted the fuel gauge at the beginning!?

 

Not 100% sure, have to pay more attention next time, but it seems that the 800L ventral tank is broken (i.e. always as good as empty)?

 

edit:

hrm, but if I flew with an 800l tank that was empty from the beginning ... 800L too little fuel would still not match that I ran out of fuel when I supposedly still had 2000l ... guess I really have to check this more thoroughly.

Edited March 18, 2015 by Flagrum

[MBot]

Then I got a flame out - while flying low and level (ACFS recovery mode). Strange, but whatever ... perhaps due to time accelleration?

Then some minutes later, next flame out - but this time I could not restart the engine.

 

This sounds a lot like overspeed. Did you surpass 1300 km/h IAS?

[Flagrum]

This sounds a lot like overspeed. Did you surpass 1300 km/h IAS?

 

Hrm, very much possible - as I was the whole time on afterburner ...

 

Thanks, will be more carefull next time. :o)

[Derbysieger]

BTW, you can easily prevent overspeeding at low altitude by flying at about 680°C EGT. Max speed at that temperature is around 1290-1295km/h indicated (at sealevel).

[Flagrum]

Yeah, I just wanted to burn as much fuel as possible in a short time ... not thinking about other potential consequences. ;o)

[Flagrum]

Tested it again, more carefull now. It's all good now from my perspective.

 

The one thing that confused me - that the fuel gauge was not set properly - was probably because I jumped into an AI MiG instead of starting the mission directly with it. Very minor issue, probably.

 

The fuel consumption I could observe matches what Beach saw and which is also in conformance with the LNS MiG manual and the US RL manual as well. The only oddity one just has to be aware of is that the external tanks are emptied in parallel, the wing tanks seemingly quicker, but when they are empty, most of the gas in the ventral tank is also already burned up. That is just the way it is, I suppose.

 

(would be cool if we could get some schematics for the MiG in the manual as detailled english literature about this aircraft is rather sparse. But I could also understand if LNS puts their priorities now on other things ;o)