FPAS Climb Setting

[drallabco]

When you box the climb option on the FPAS, you get an airspeed for best climb on the HUD. A couple of questions regarding this:

 

1. What is this climb speed giving? Vy? A cruise climb for Max Range? A fuel conserving climb for Max E? Because these speeds will all be different.

 

2. What is the power setting for this climb speed? There can be any number of combinations of pitch and power to get that speed, but obviously, you'll be burning more if you're full burner and 30º pitch up. Best guess is that it's a mil power climb and you're pitching for the airspeed on the HUD.

 

3. Is there a way to set ATC to hold FPAS Climb Airspeed?

[Razi]

I asked this question to a Hornet driver before. I've been told the following:

 

1. The CLIMB function shows “optimum climb speed". It was a best climb schedule speed. Basically an energy function climb. It follows the bingo charts in NATOPS, but uses your actual realtime weight.

 

2. MIL Power

 

3. No. ATC holds KTAS and the CLIMB function shows KCAS. In practice, ATC is generally used only in level flight where KTAS and KCAS remain the same.

[Nooch]

1. So it's for best range basically, right?

[Ramsay]

When you box the climb option on the FPAS, you get an airspeed for best climb on the HUD. A couple of questions regarding this:

 

1. What is this climb speed giving? Vy? A cruise climb for Max Range? A fuel conserving climb for Max E? Because these speeds will all be different.

 

Truth is, I don't know but I'll pass on what I've found.

 

2. What is the power setting for this climb speed? There can be any number of combinations of pitch and power to get that speed, but obviously, you'll be burning more if you're full burner and 30º pitch up. Best guess is that it's a mil power climb and you're pitching for the airspeed on the HUD.

 

The performance charts (NFM-200) have 3 types of climb profile

 

• Climb Mil Thrust i.e. 360 CAS, then 0.81 Mach

• Climb Max Thrust, Peak Rate Climb i.e. S.L. = 0.799 Mach 527 TAS, 20,000 ft 0.835 Mach

• Bingo Climb Mil Thrust i.e. 475 CAS, then 0.86 Mach

 

The DCS F/A-18C takes more distance/time to reach it's optimum cruise altitude than the NFM-200 charts suggest i.e. the DCS F/A-18C looks draggier.

 

Following the FPAS climb prompt, using Mil Thrust, results in a shallow climb that takes much longer than a 350/0.8 profile. The FPAS figures do look similar to the suggested 'Bingo' Mil climb even if they don't work so well in game.

 

Using Max Thrust to follow the DCS FPAS climb works much better, though distance and time is still longer than in the 'Climb Max Thrust' charts.

 

I expected a 'Max Thrust climb to optimum altitude' to adversely effect range, but it seems not to have much effect, presumably the shorter time needed to climb, offset the higher fuel rate.

 

I tested a few weeks back, in the Persian Gulf, so it's possible things have since changed. In terms of fuel use, I didn't do a 'back to back' comparison or note the fuel remaining, just that I didn't need to change the mission profile and still had plenty of reserve fuel when I return to base. YMMV

 

3. Is there a way to set ATC to hold FPAS Climb Airspeed?

AFAIK, that's not how the climb profile is flown, you set a fixed throttle/power setting i.e. Mil or Max, and adjust aircraft pitch to maintain the required speed, not adjust the throttle setting (which is what the ATC does).

Edited February 19, 2019 by Ramsay

[=Mac=]

A bit off topic but I need to ask: the Home Fuel warning is based on your takeoff location. Is there a way to (a) turn the warning off and (2) change the Home location (for example, leaving shore for the boat)?

[Rainmaker]

A bit off topic but I need to ask: the Home Fuel warning is based on your takeoff location. Is there a way to (a) turn the warning off and (2) change the Home location (for example, leaving shore for the boat)?

 

 

Selecting a non-existant waypoint on the FPAS page will disable the home duel. I.E. you have 8 waypoints and you select waypoint 20.

 

Be advised, unless something has changed, this will permanently disable it for the rest of the flight as the WP sepect buttons will disappear after a few seconds. The RL flight manual kind of hints at this being realistic on the disable part, but doesnt really speak to whether or not it can be reenabled in the real thing.

[Ramsay]

Is there a way to

 

(a) turn the warning off

Yes, on the FPAS page change the 'Home' waypoint (default is '0') to one that isn't in your flight plan i.e. use the down arrow to go from '0' to '59'

 

(2) change the Home location (for example, leaving shore for the boat)?

Home is just a waypoint, so if waypoint 13 was near the boat, you'd set that