Couple of Questions re F-16 throttle use and QFE on Afghan map

[DrDetroit]

Hi guys,

So in reality, is it appropriate to stay full mil power when in cruise mode to from waypoints?  I use to tend to stay in full mil power most of my flight, if no issue with fuel consumption, TOT, and such.  However, seems that in reality that may cause early wear on the engine?  I kind of knocked that back to 95ish percent as of late.  What's the general rule for full mil power use?

Also, on the Afghan map, I get QFE callouts from tower of around 84.xx at Kabul.  Thing is, mine is set at around 96.xx-97.xx by default, and I can't dial it back below around 95.xx.  So I just set it at 5K at runway level.  What do you guys set your QFE when this happens?

Anyhow, just curious, and thanks in advance!

Good day!

DrDetroit  

Edited Sunday at 01:22 PM by DrDetroit

[NytHawk]

25 minutes ago, DrDetroit said:

So in reality, is it appropriate to stay full mil power when in cruise mode to from waypoints? 

Usually its advisable to fly a bit slower, you will save quite a lot of fuel.
You can use the RNG mode in the CRUS DED page to show the most efficient cruising speed for the given altitude on the HUD. 

[Tholozor]

1 hour ago, DrDetroit said:

Also, on the Afghan map, I get QFE callouts from tower of around 84.xx at Kabul.  Thing is, mine is set at around 96.xx-97.xx by default, and I can't dial it back below around 95.xx.  So I just set it at 5K at runway level.  What do you guys set your QFE when this happens?

Ignore QFE callouts from tower, use QNH.

Edited Sunday at 02:21 PM by Tholozor

[Exorcet]

55 minutes ago, DrDetroit said:

Hi guys,

So in reality, is it appropriate to stay full mil power when in cruise mode to from waypoints?  I use to tend to stay in full mil power most of my flight, if no issue with fuel consumption, TOT, and such.  However, seems that in reality that may cause early wear on the engine?  I kind of knocked that back to 95ish percent as of late.  What's the general rule for full mil power use?

Also, on the Afghan map, I get QFE callouts from tower of around 84.xx at Kabul.  Thing is, mine is set at around 96.xx-97.xx by default, and I can't dial it back below around 95.xx.  So I just set it at 5K at runway level.  What do you guys set your QFE when this happens?

Anyhow, just curious, and thanks in advance!

Good day!

DrDetroit  

Putting aside wear, cruising at mil power is unusual because it's not efficient. The F-16 will fly from Mach 0.7 to 0.9 during cruise depending on load and altitude.

I typically climb to cruise alt at mil power (pitching to maintain 350 KCAS or Mach 0.9(AA load) / 0.82 (AG load), whichever is greater) and then dial back to cruise setting.

 

1 hour ago, DrDetroit said:

Hi guys,

So in reality, is it appropriate to stay full mil power when in cruise mode to from waypoints?  I use to tend to stay in full mil power most of my flight, if no issue with fuel consumption, TOT, and such.  However, seems that in reality that may cause early wear on the engine?  I kind of knocked that back to 95ish percent as of late.  What's the general rule for full mil power use?

Also, on the Afghan map, I get QFE callouts from tower of around 84.xx at Kabul.  Thing is, mine is set at around 96.xx-97.xx by default, and I can't dial it back below around 95.xx.  So I just set it at 5K at runway level.  What do you guys set your QFE when this happens?

Anyhow, just curious, and thanks in advance!

Good day!

DrDetroit  

As far as airport operations go, use ILS and radar altimeter to determine where you are in relation to the airfield.

[DrDetroit]

10 minutes ago, Tholozor said:

Ignore QFE callouts from tower, use QNH.

Ah, ok.  Thanks for the heads up!  How to switch to QNH?  

[Tholozor]

20 minutes ago, DrDetroit said:

Ah, ok.  Thanks for the heads up!  How to switch to QNH?  

The tower system is antiquated, and has no ability to provide QNH, however, it's available in the mission briefing.

[Furiz]

1 hour ago, DrDetroit said:

Hi guys,

So in reality, is it appropriate to stay full mil power when in cruise mode to from waypoints?  I use to tend to stay in full mil power most of my flight, if no issue with fuel consumption, TOT, and such.  However, seems that in reality that may cause early wear on the engine?  I kind of knocked that back to 95ish percent as of late.  What's the general rule for full mil power use?

Hey, 

I learned some time ago that with same percentage on the engine RPM the fuel flow will wary depending on height/air thickness, temperature humidity etc, so I trained myself to watch fuel flow, and realised that around 5800ish pph is optimal and mach 0.65 to 0.70. I guess that's why that fuel flow indicator is positioned so high on the instrument panel, so you can glance at it easily. Must have been an important tool

Mil power is, in my opinion, to be used when you are engaging targets, or in high risk zones etc, obviously you need speed to clear out if some launch happens. But when cruising on the way to area of operations I like to use fuel flow and keep it around 5800pph.

 

[DrDetroit]

Thanks to everyone for very informative posts!  This helps a lot. 

[cw4ogden]

@DrDetroit The pilot trying to limit potential Engine wear isn't really a factor.  Fuel for sure, but the difference between 95% and 100% power, in terms of wear, would negligible.   

[MeanJim]

You can fly around at MIL power all you want, and you're not going to hurt the engine as long as you don't exceed 1100°C FTIT.  When possible, cruise as high as possible.  At higher altitudes the air is thinner, and even at full MIL you won't make full power anyway.  This past Saturday I was RTBing over 200 miles and fuel was tight.  I was at 38,000ft and at full MIL the RPM maxed out at 93%.

I do similar to Exorcet, and climb at full MIL power maintaining 350KTS IAS.  When I can no longer maintain 350KTS IAS, I climb at 2-3° until AOA gets to 5° and level off to gain airspeed, then start reducing power to maintain 5000-6500PPH fuel flow.  Generally with a heavy A-G loadout, I'll make 20-25,000 ft and set 6000-6500PPH, and A-A I go for 30-35,000 and set 5000-5500PPH.

One of the CRUS pages shows the optimum altitude for fuel efficiency.  At that altitude, full MIL power will also give the optimum speed.

[Spartan111sqn]

1 hour ago, MeanJim said:

You can fly around at MIL power all you want, and you're not going to hurt the engine as long as you don't exceed 1100°C FTIT.  When possible, cruise as high as possible.  At higher altitudes the air is thinner, and even at full MIL you won't make full power anyway.  This past Saturday I was RTBing over 200 miles and fuel was tight.  I was at 38,000ft and at full MIL the RPM maxed out at 93%.

I do similar to Exorcet, and climb at full MIL power maintaining 350KTS IAS.  When I can no longer maintain 350KTS IAS, I climb at 2-3° until AOA gets to 5° and level off to gain airspeed, then start reducing power to maintain 5000-6500PPH fuel flow.  Generally with a heavy A-G loadout, I'll make 20-25,000 ft and set 6000-6500PPH, and A-A I go for 30-35,000 and set 5000-5500PPH.

One of the CRUS pages shows the optimum altitude for fuel efficiency.  At that altitude, full MIL power will also give the optimum speed.

when you were at 38.000ft, I can imagine that you were fully clean, no fuel tanks...

 

Normally 5º AOA is for maximum range at any given altitude, that thumb rule that works, 7º AOA is for maximum endurance at any altitude, anothe thimb rule.

 

when you are in AA 35.000ft, I can imagine that is without any fuel tank, otherwise, you enter in second regime and the AOA of the aircraft and lack of engine response push you to go lower.

Normally in a CAP, if you are above a friendly zone (DCA), you can patrol more in Endurance. But if you are in a contested zone, you have to CAP faster,  that would be around M 0.85.

Edited Monday at 01:10 PM by Spartan111sqn

[Spartan111sqn]

Also the quantity of weight you have of fuel has a big influence in the viper, you can be just top off after AAR, and barely you can't go beyond FL310 M0.83 and perform a turn smaller than an Airbus, the aircraft starts to slow down even if you are in full MIL and more than 30º of bank with 2xExt, 4x120C,2Aim9.

 

But in the same situation when you have consumed more fuel and you have for example 7000lbs, keeping the same loadout the aircraft performs better, so the drag index is the same, but the weight is around 4.000lbs lower.

[MeanJim]

23 hours ago, Spartan111sqn said:

when you were at 38.000ft, I can imagine that you were fully clean, no fuel tanks...

 

Normally 5º AOA is for maximum range at any given altitude, that thumb rule that works, 7º AOA is for maximum endurance at any altitude, anothe thimb rule.

 

when you are in AA 35.000ft, I can imagine that is without any fuel tank, otherwise, you enter in second regime and the AOA of the aircraft and lack of engine response push you to go lower.

Normally in a CAP, if you are above a friendly zone (DCA), you can patrol more in Endurance. But if you are in a contested zone, you have to CAP faster,  that would be around M 0.85.

I was as clean as I could get.  I was still carrying my empty external wing tanks, and I think two AMRAAMs, but when I realized my fuel situation was critical I jettisoned the tanks and racks.  I had a couple of unexpected events on the way in and I had forgotten about that I got the bingo fuel warning, and even then I overstayed a little bit to drop my last bomb.  I knew I needed to hyper mile it to get back.  I landed with just under 500lbs. of fuel.

When I'm doing A-A, it's usually more of a fighter sweep or intercept, so I'm usually not cruising for long.  I will take two wing tanks, and a jammer if there might be SAMs in the area.  I go full burner up to 30-35,000ft then cruise if needed.

That's good to know about the AOA.  A while back I did a search for the F-16's best climb rate, and I remember seeing 350Kts, but the 5° AOA thing I just started doing because the jet just feels good there.