Engine Start Order

[Avio]

The right engine is started first, reason being for hydraulic pressure check on the utility hydraulic. But both PC1 and PC2 reach 3000 psi upon engine engage, with the utility showing 2750psi before going to 3000 after engine 2 start. Can’t we just start left engine first instead?
 

On a separate question, the Tank 1 at the fuel switch refers to all of the fuselage tanks right? Why not just call it Fuselage Tank then?

 

 

[Rudel_chw]

6 hours ago, Avio said:

The right engine is started first, reason being for hydraulic pressure check on the utility hydraulic. But both PC1 and PC2 reach 3000 psi upon engine engage, with the utility showing 2750psi before going to 3000 after engine 2 start.

 

the utility system has two pumps, left operates at 3,000 and right at 2,750 … but they share a single pressure gauge.

 

6 hours ago, Avio said:

Can’t we just start left engine first instead?

yes, but you won’t be able to tell if the right utility pump is really operating.

 

6 hours ago, Avio said:

On a separate question, the Tank 1 at the fuel switch refers to all of the fuselage tanks right? Why not just call it Fuselage Tank then?

no, tank 1 is a single 600 gallon tank, thats why the tank1 position of the gauge shows only on the left gauge while the right one is zero.
 

[Avio]

Thanks much, Rudel. About Tank 1, what I meant is, is it or is it not that Tank 1 refers to the total combined fuel cells that lined up along the central fuselage body?

In other words, Feed Tank + Internal Wing Tanks + Tank 1 + Ext Wing Tanks + Ext Center + CFT = That digit number shown on the indicator.

 

[jaylw314]

39 minutes ago, Avio said:

Thanks much, Rudel. About Tank 1, what I meant is, is it or is it not that Tank 1 refers to the total combined fuel cells that lined up along the central fuselage body?

In other words, Feed Tank + Internal Wing Tanks + Tank 1 + Ext Wing Tanks + Ext Center + CFT = That digit number shown on the indicator.

 

No, there are 4 fuselage tanks--Tank 1 Main, Tank 1 Right Aux, Left Feed and Right Feed.  The two feed tanks are on the FEED channel on the fuel display.  Tank 1 combines the Tank 1 main and aux tanks (I think)

[Rudel_chw]

3 hours ago, jaylw314 said:

Tank 1 combines the Tank 1 main and aux tanks (I think)

Yes, the gauge displays the total of Tank 1 main+aux, in fact the TO 1F-15E-1  manual does not tell what is their individual  capacity, only the sum of both (604 Gal).

Edited September 26, 2023 by Rudel_chw

[Avio]

In the attached pic, which is tank 1 and which is aux? And the two feed tanks, they are hidden below those shown fuselage tanks in the picture?

*Edit* And what is the aux tank for? Any special purpose?

Edited September 27, 2023 by Avio

[Rudel_chw]

26 minutes ago, Avio said:

which is tank 1 and which is aux? And the two feed tanks, they are hidden below those shown fuselage tanks in the picture?

No idea, the manual only says "Fuel is carried internally in four interconnected fuselage tanks, and two internal (wet) wing tanks. External fuel can be carried in three external tanks and two conformal fuel tanks. The external tanks are mounted on the centerline and inboard wing station pylons and are completely inter- changeable. CFT‘s are mounted on the outboard side of each engine nacelle. " but does not indicate the exact location of the internal tanks … in any case, what would be its relevance?

[draconus]

Tank 1 consists of main internal tank and right aux tank. The latter might help with gravity fuel transfer from what I read.

[BIGNEWY]

Hi all, 

if you are posting images from real world manuals please include the source and verify it is unclassified and for public use. We can not always tell and will hide posts if we can not confirm its origin. 

A reminder of our rules 

1.16 Posting of screenshots, images, file links, file sharing links, and copying and pasting information is prohibited if the source document has a limited distribution statement or it is classified. Limited distribution includes DoD Distribution Statement C, Distribution Statement D, Distribution Statement E, Arms Export Control Act, Export Administration Act, and International Traffic in Arms Regulations (ITAR) controlled sources. When posting aircraft, sensor, or weapon information more recent than 1980, you must also include the source of the document that demonstrates that it is 100% public and verified as not from a limited distribution source as listed.

 

thank you

[Ramsay]

On 9/27/2023 at 1:59 AM, Avio said:

In the attached pic, which is tank 1 and which is aux?

• Item 6 is "Tank 1" and includes "Tank 1 Aux Tank" as part of it.

This "Haynes" F-15 diagram is likely the best I can do without directly referring to a F-15E Student "Workbook".

On 9/27/2023 at 1:59 AM, Avio said:

And the two feed tanks, they are hidden below those shown fuselage tanks in the picture?

• Item 5 is the Right Engine Feed Tank (Tank 2)
• Items 3 and 2 are the Left Engine Feed Tank (Tank 3A and 3B)

Source

Spoiler

https://haynes.com/en-au/mcdonnell-douglasboeing-f-15-eagle-manual

 

Edited September 28, 2023 by Ramsay
Add details on Right and Left feed tank labels.

[Avio]

Wow ! Thanks much Ramsay. A picture tells a thousand words truly.

[jaylw314]

6 hours ago, BIGNEWY said:

Hi all, 

if you are posting images from real world manuals please include the source and verify it is unclassified and for public use. We can not always tell and will hide posts if we can not confirm its origin. 

Sorry about that, I snipped that off someone's website, I went back and double-checked and it did seem to be taken from an official document

[BIGNEWY]

2 hours ago, jaylw314 said:

Sorry about that, I snipped that off someone's website, I went back and double-checked and it did seem to be taken from an official document

no problem easily done as there is so much out there, but we have to be very cautious. Thank you

[jaylw314]

8 hours ago, Ramsay said:

• Item 6 is "Tank 1" and includes "Tank 1 Aux Tank" as part of it.

This "Haynes" F-15 diagram is likely the best I can do without directly referring to a F-15E Student "Workbook".

 

 

  Reveal hidden contents

https://haynes.com/en-au/mcdonnell-douglasboeing-f-15-eagle-manual

 

 

That's pretty awesome, do you actually have that Hayne's manual?  

It's interesting that it's called the "Tank 1 Right Aux" but it's actually on the left side?? 

[Rudel_chw]

1 hour ago, jaylw314 said:

It's interesting that it's called the "Tank 1 Right Aux" but it's actually on the left side?? 

On the manual of the real thing, the tanks have these names:

 

Tank 1 (this is the only tank with a number)

Right Aux Tank

Right Engine Feed Tank

Left Engine Feed Tank

Right Internal Wing Tank

Left Internal Wing Tank

Right Conformal Fuel tank

Left Conformal Fuel tank

Right Wing External Fuel tank

Left Wing External Fuel tank

Centerline tank

 

[Ramsay]

17 hours ago, jaylw314 said:

It's interesting that it's called the "Tank 1 Right Aux" but it's actually on the left side?? 

I believe* the Aux tank is symmetrical (i.e. mirrored on the right side), in the workbook it's labelled "Tank 1 Aux Tank", it's piped to/through the Right Engine Feed Tank i.e. the tank behind it, perhaps that's where the "Right Aux" label comes from ?

* Block diagrams show Tank 1 + Aux as symmetrical, however isometric views in the workbook only show the perspective from the LH side, so I can't be 100% certain.

16 hours ago, draconus said:

Looks like it's only @Ramsay's interpretation.

I'm using the terms from the 1998 F-15E Student Workbook for the Fuel System where "Tank 1 Aux Tank" is labelled as such - however for the purpose of the workbook's fuel line schematics Tank 1 and the Aux Tank are treated as one unit (so it's not documented in detail).

Unfortunately I can't post diagrams from the workbook (I tried) as the information is more recent than 1980 and the workbooks don't include "public distribution" notices.

 

Edited September 28, 2023 by Ramsay
F-15E Workbook does not label the Aux Tank as "Right"

[strikeeagle]

1 hour ago, Rudel_chw said:

On the manual of the real thing, the tanks have these names:

 

Tank 1 (this is the only tank with a number)

Right Aux Tank

Right Engine Feed Tank

Left Engine Feed Tank

Right Internal Wing Tank

Left Internal Wing Tank

Right Conformal Fuel tank

Left Conformal Fuel tank

Right Wing External Fuel tank

Left Wing External Fuel tank

Centerline tank

 

That’s funny because when I was teaching the airplane, it was Tanks 1, 2, 3A & 3B.  But what do I know.

 

[jaylw314]

20 minutes ago, Ramsay said:

I believe* the Aux tank is symmetrical (i.e. mirrored on the right side), presumably it's called the "Right" Aux tank because it's piped to/through the Right Feed Tank (that feeds the right engine) i.e. the tank behind it.

* Block diagrams show Tank 1 + Aux as symmetrical, however isometric views in the workbook only show the perspective from the LH side, so I can't be 100% certain.

Oooooh, okay, that would make more sense  

[Avio]

Note to Rudel_chw --

I extracted this segment (see attached) from the checklist you posted before, and it shows PC2 after right engine started should read 2750 psi, but the PC2 gauge shows 3000. Which is correct?

And if 3000 at PC2 is right, I am not sure how starting left engine first would make any difference, since PC1 reads 3000 as well after left engine started.

 

[Rainmaker]

Checklist is wrong

 

EMD and hydro are not even related

Edited September 28, 2023 by Rainmaker

[Avio]

28 minutes ago, Rainmaker said:

Checklist is wrong

 

EMD and hydro are not even related

 

Maybe you could help advise what would be right?

 

[Rainmaker]

8 minutes ago, Avio said:

Maybe you could help advise what would be right?

 

The same as already said earlier.  The one that matters is the Util press.  Right side = 2750.  Left = 3000

PC1 and PC2 are 3K regardless

Edited September 28, 2023 by Rainmaker

[Avio]

14 minutes ago, Rainmaker said:

The same as already said earlier.  The one that matters is the Util press.  Right side = 2750.  Left = 3000

PC1 and PC2 are 3K regardless

 

Thanks for confirming that both PC1 and 2 should be 3000. That helps !

[WizzRD]

On 9/26/2023 at 6:01 AM, Avio said:

Can’t we just start left engine first instead?

One thing that may play into the right vs left choice is that in pretty much any start up video you see, the right engine starts while the canopy is still open and the ladder still attached. Guess noone would like to get sucked in or hit by the inlet coming down.

[Rudel_chw]

5 hours ago, Avio said:

Note to Rudel_chw --

I extracted this segment (see attached) from the checklist you posted before, and it shows PC2 after right engine started should read 2750 psi, but the PC2 gauge shows 3000. Which is correct?

the checklist is incorrect, it’s the Utility gauge the one that should read 2,750 psi.