FCR Manual DRAFT

[rmax]

Fellow aviators. I have spent the last month writing the attached manual for the AN/APG 68 manual to act as a supplementary to the current information in the -1 and -34, and extending from the excellent manual that Stephen French did all those years ago.

Feedback welcome (ducks behind the parapet). I will update/extend if there is enough interest.

v2 Updated with various comments from this thread + updated diagrams and text.

[johku]

For those who haven’t seen it, Stephen “HotDogOne” French wrote an AN/APG-68 radar guide in 2001 for eFalcon:

http://www.mediafire.com/download/13095icis2ejrlb/Guide_-_Radar.pdf

[hoover]

Excellent work, thanks for sharing it with the BMS community!

Uwe

[Red Dog]

Thanks I’ll be sure to check this out

[rmax]

I have the greatest respect Red Dog for the manuals you wrote for -1 and -34. After my foray into the FCR it is hardwork.

[Focaldesign]

Looks nice. Could it be you swapped low & high transmit power?

Peak Transmit power 17.5 kW at low duty (0.03 max) 1.75 kW at high duty (0.45 max)
I’m no electrician, so I could be wrong, but I would expect 1.75 at low duty and 17.5 at max, no?

[Focaldesign]

second question:

The Radar will enter a Non Radiation condition and NO RAD is displayed in the HUD on one of the following conditions:
1/ Weight on Wheels (WOW) to prevent ground personnel being injured

I was also told this is the case, but in BMS we don’t see NO RAD on the HUD during WOW unless you manually press the OVR OSB. Is this a mistake in BMS (the not showing NO RAD on HUD I mean) or is the manual wrong and is the norad condition correct but doesn’t really say NO RAD at WOW?

[Focaldesign]

on page 12

Radar ranged scale. It can be altered through using OSB 20 (up arrow) and OSB 19 (down arrow). The figure shows 40 which means the number of miles from the bottom of the display to the top of the display
Maybe good to also note that you can change the range by bumping the radar cursor all the way to the top (increase range) or bottom (decrease range) of the scope.

on page 14 (nitpicking here)

PM OFF is the Power management and alternates between PM ON & PM OFF (NI).
I think this has suppose to have “PM OFF” in bold and with an additional brake before it to be in same layout as the other parts of that section.

[rmax]

Nitpick away! there is no-one I know that I could get to proof read!

I am thinking about your other questions…

[Focaldesign]

page 29

The cursors can be slewed, however not when the cursor is slewed it enters a delta into the SPI

I think the “not” was ment to be “note”?

[Focaldesign]

glossary on last page

• No explanation next to PRF
• WOW is weight ON wheels, instead if IN

[Jetlag]

@Focaldesign:

I was also told this is the case, but in BMS we don’t see NO RAD on the HUD during WOW unless you manually press the OVR OSB. Is this a mistake in BMS (the not showing NO RAD on HUD I mean) or is the manual wrong and is the norad condition correct but doesn’t really say NO RAD at WOW?

These videos would suggest that NO RAD is not normally displayed during WOW

Quite the opposite could actually be suggested by this video where NO RAD seems to appear after wheels-up

So potentially there is no warning during WOW because it is taken as read by the pilot that radar is disabled during WOW and only needs the warning after wheels-up?

[Terminator]

@Jetlag:

These videos would suggest that NO RAD is not normally displayed during WOW

Quite the opposite could actually be suggested by this video where NO RAD seems to appear after wheels-up

So potentially there is no warning during WOW because it is taken as read by the pilot that radar is disabled during WOW and only needs the warning after wheels-up?

Yes, that’s the right assumption

[Raptor]

I can help make this more interesting… Will ping you when have some time to read this version.

[rmax]

QQ. I had included COAST operating mode in the manual in summary form (not some of the details). Is COAST supported in BMS4.33 U1?

[Darkman]

Looking forward to reading a BMS Manual that I haven’t read dozens of times

Thank you for the effort and time you obviously put into this.

[Fox3TwoShip]

I’d differentiate between the 2 versions of the APG-68 (V1 for Blk 40s and V5 for Blk 50s).

Page 4:

The radar consists of six functional line replaceable units(LRUs)
There are only 4.

Page 5:

Beam width 3.25 deg azimuth, 4.55 deg elevation
Every piece of documentation I’ve ever read (that pilots actually care about) it says 3.3x4.6. However, the FCR handbook might give the exact numbers (what engineers care about). So take it FWIW.

Page 7:

The system then passes the information to the PSP, where it is interpreted and passed onto the Fire Control Computer (FCC)
What is PSP? I assume Programmable Signal Processer. Additionally, the FCC doesn’t exist in Blk 40s and 50s anymore; it’s the MMC.

Page 7:

Diagram showing ULS as Ultra Long Scan
This is actually Uplook Search

Page 15:

However RWS will paint a target for a brief period of time, and hence there is a reduced change to be detected by any Radar Warning Receiver equipment.
Hmm… not exactly… I think you’re thinking of TWS; where much less time is spent looking at a contact.

Page 16:

Ultra Long Range Scan
This is the same as RWS but is optimised for finding targets at long range.
This is actually Up-Look Search. You’re correct that it will find contacts at longer ranges. This is because it doesn’t do all the processing to filter out clutter. So you will get a lot of false targets. It should only be used in an up-look, clutter-free environment. (We never use it…)

Page 17:

TWS. Support three scan patterns: ± 60, 2 bar, ± 25, 3 bar, ± 10, 4 bar
I believe this to be true in BMS (still); however, real world you don’t have the ± 60, 2 bar option;

Page 18:

Velocity Search
Nowadays this is actually Velocity Search with Ranging (VSR). I’m not sure if this exists in BMS or not. However, in the next page you mention VSR (so I assume BMS implements it). If you are talking about VSR then you have described the display incorrectly. Faster contacts do not display at the top, and slower contacts at the bottom. They display the same way they would in RWS.

Page 21:

Intercept Steering Cue that provides the Steering Cue to the pilot for a pure pursuit course to intercept the bugged target (horizontal cue only)
Half true… You can set all 3 pursuits depending on where you place the CATA cross. Yes, if you place the cross in the center of the MFD then you are on a collision course. But I can set a lag or lead pursuit just as well.

Page 26:

The boresight is the width of the beam out to 10 nm.
Not sure how this is implemented in BMS, but real world this actually goes out to 40 NM. It is the only ACM mode to do so.

Page 27:

Slew can be entered from any of the ACM submodes by slewing the acquisition cursor controls. On selection a body stabilised
Unfortunately, this is not how BMS should work. It should be space-stabilized as it’s very disorienting with it being body-stabilized.

[rmax]

Fox3TwoShip, thanks for the additional details. I believe that you are a throttle/stick interconnect so I will take your comments and edit. Most of the information I could find about the technical implementation was AN/APG 66 and not the 68, so thanks for the additional data!

[rmax]

@Darkman:

Looking forward to reading a BMS Manual that I haven’t read dozens of times

Thank you for the effort and time you obviously put into this.

Now that is praise - just for the effort. When I was doing it realised just how much effort you must have put into the -1 and -34!

[Jetlag]

@rmax:

Nitpick away! there is no-one I know that I could get to proof read!

I am thinking about your other questions…

Looks good - thanks for the hard work putting it together - already explaining some points which I did not quite get before

Just some spelling typos:
Page 13 - Master Mode Select: will select between CRM (Combined Radar Modes)

Page 18 - Velocity Search interleaves a high PRF mode with a medium PRF mode