AUX fuel transfer - when to activate?

[sirrah]

In this video from @Casmo, at about 20m18s he's talking about the aux tank and that it has to be activated manually (if installed).

He also says that this is generally done within the first 30mins after take off. I am wondering though, as I always forget this during flight, is there any particular reason why the aux transfer shouldn't just be activated right after engine start, when the fuel page is active on the right mpd anyway?

 

[Rudel_chw]

52 minutes ago, sirrah said:

is there any particular reason why the aux transfer shouldn't just be activated right after engine start, when the fuel page is active on the right mpd anyway?

 

Good question .. the manual of the real aircraft doesn't say anything about at what moment start using the axiliary tanks. The external tanks do not have fuel measurement probes and so their content is not added automatically to the Fuel total, you should enter it using the AUX GALLONS EXT button, on the fuel page:

 

Edited April 19, 2022 by Rudel_chw

[Bunny Clark]

I always just enable it with startup.

[Raptor9]

21 minutes ago, Rudel_chw said:

it seems that the DCS Apache does not have such a probe, as the IAFS tank content is not added automatically to the Fuel total

It does, otherwise there would be an AUX GALLONS INT> at L6 right below the AUX GALLONS EXT> at L5.  The 230-gallon external fuel tanks under the wings are un-probed, so those have to be manually added.  Not all IAFS were initially probed when fielded, but the DCS Apache is simulating an IAFS with the probe.

1 hour ago, sirrah said:

He also says that this is generally done within the first 30mins after take off. I am wondering though, as I always forget this during flight, is there any particular reason why the aux transfer shouldn't just be activated right after engine start, when the fuel page is active on the right mpd anyway?

Since this is a sim, you surely can.  There are several reasons and methods for managing the internal aux tank in real life, some of them written in documents and others are based on recommendations from maintenance test pilots.  Some will turn it on to make sure it is working immediately after takeoff and then switch it off until they burn off more fuel in the main tanks, some will wait until the total fuel onboard is less than 2500 pounds meaning that the entirety of the IAFS can be emptied since the main fuel tanks combined capacity is 2500 lb.

As for how to remind oneself to do it, you can use the fuel check timer to keep you on top of it.  A common technique was waiting for the 2nd 30-min fuel check to complete and then starting the IAFS since that would ensure enough fuel would be burned off from the mains in 1 hour of flight time.

Just keep in mind though that even when switched on, the C AUX will not pump gas if external fuel tanks under the wings are in the process of transferring fuel to the main tanks, or if there is fuel being transferred between the main tanks (whether automatically or manually commanded).

Edited April 19, 2022 by Raptor9

[Rudel_chw]

3 minutes ago, Raptor9 said:

Not all IAFS were initially probed when fielded, but the DCS Apache is simulating an IAFS with the probe.

 

Yes, you are totally correct ... I realized my mistake and edited my post a few minutes ago.

[Raptor9]

Just now, Rudel_chw said:

Yes, you are totally correct ... I realized my mistake and edited my post a few minutes ago.

Ah, gotcha.  It took me a few more minutes to type out the explanation in the 2nd part of my post.

[Rogue Trooper]

I tend to activate the aux/robin tank when I think the fore and aft tanks look a bit low. It can be 1 hour into the flight.

it would probably be more interesting whether shifting weight to the rear tank is more advantageous.

The huge tail stabilizer concerns me more. Big working aerodynamic surface.... It just draws my interest..... I do not like the nudge up/down function though! 

Edited April 20, 2022 by Rogue Trooper

[sirrah]

9 hours ago, Raptor9 said:

As for how to remind oneself to do it, you can use the fuel check timer to keep you on top of it.  A common technique was waiting for the 2nd 30-min fuel check to complete and then starting the IAFS since that would ensure enough fuel would be burned off from the mains in 1 hour of flight time.

 

Thanks for all the reactions guys!

The fuel check timer? Could you expand a little on this? (Is there an actual timer with a notification alarm of some sort?)

And what is this 30-min fuel check?

[Hoirtel]

Am I right in thinking then this tank should not be used if not enabled? I have always linked it up on start-up as Wags did but I'm pretty sure I used the fuel in it anyway even when I have forgotten to do this.  I'll have to check again to be sure.

Edited April 20, 2022 by Hoirtel

[Raptor9]

4 hours ago, sirrah said:

The fuel check timer? Could you expand a little on this? (Is there an actual timer with a notification alarm of some sort?)

And what is this 30-min fuel check?

It's in the quick start manual.

[Rudel_chw]

5 hours ago, sirrah said:

And what is this 30-min fuel check?

on the figure above, its the B6 button: CHECK

[sirrah]

1 hour ago, Rudel_chw said:

on the figure above, its the B6 button: CHECK

Ah, thanks

Still a lot to learn. I'll have a look in the quick start manual.

[Rudel_chw]

27 minutes ago, sirrah said:

Ah, thanks

Still a lot to learn. I'll have a look in the quick start manual.

 

You are welcome .. I just love the detail in DCS, the FUEL page works exactly as described on the manual of the real helo   ... I just wish that there was a special option to disable this auxiliary tank, in order to have more gun ammo.

[Kharrn]

vor 51 Minuten schrieb Rudel_chw:

 

You are welcome .. I just love the detail in DCS, the FUEL page works exactly as described on the manual of the real helo   ... I just wish that there was a special option to disable this auxiliary tank, in order to have more gun ammo.

afaik 12-PAK (1200 rounds) and maybe even 6-PAK (600 rounds) will come during EA.

dont have the source to quote but i think it was in one of Wags videos.

https://meggittdefense.com/product/apache-30mm-12-pak-magazine/?doing_wp_cron=1650467453.6491301059722900390625

K

 

[Raptor9]

There's no such thing as a 600 round magazine in the US Army. I've never heard of such a thing either, but I won't speak for foreign versions.

But yes, 1200 round magazine coming later in EA.

[Kharrn]

vor 25 Minuten schrieb Raptor9:

There's no such thing as a 600 round magazine in the US Army. I've never heard of such a thing either, but I won't speak for foreign versions.

But yes, 1200 round magazine coming later in EA.

Hey Raptor, thy for that insight info

Sry to be so off-topic here:

Zitat

In 1979, Hughes Helicopter’s Ordnance Group (now ATK Gun Systems) and Meggitt Defense Systems (formerly Western Design) joined forces to apply Linear Linkless™ technology to
the problem of feeding the family of lightweight 30mm ammunition to the Hughes M230 chain gun. 120 days after contract award, Meggitt Defense Systems delivered the 6-PAK. This single bay magazine, the precursor of the 12-PAK, stored 600 light-weight 30mm rounds in a vertical orientation and handed them off to the AH-64’s carrier system, which interfaced with the M230 chain gun.

Source: https://meggittdefense.com/wp-content/uploads/2020/03/12-PAK-magazine.pdf

Guess it was never fielded or only for prototype usage

BTT now