Cruising Altitude

[CybrSlydr]

What altitude and speed do you folks typically use for cruising between steerpoints?

 

I typically use 15,000ft baro at 90% throttle.

[delevero]

It depend how heavy you are.

If you have a full load of bombs and fuel tanks, then a guess 27.000 ( right below where you start to contrail. )

 

If you only have AA weapons and fuel then above the Contrail zone

guess 37.000feet.

 

BUT if you actual plan to go down and fight, or go into dogfight then be very aware that all the fuel you spend on going up so high you might miss when you want to go home again.

 

Going really high i would say is only usefull when you have 2 bombs and fuel tanks and want to go very far or fly very fast ( but you also be very easy to spot via radar ) so i guess its mostly usefull in friendly territory or when you ferry from a-b.

 

I guess on average go for example 27.000feet or if you make no contrail 30.000ft.

 

Im no expert, but its not a bad advice ;-)

[Harker]

Until we get the CRUS page, my ballpark is between 25k and 35k ft, around Mach 0.7-0.75 for cruising and around 25k ft and Mach 0.55 for loitering.

[wrl11]

I base ours off of the F18 FPAS page until we get the F16 one. Usually it shows best range is around 32-34K and Mach .82. Depends a bit on weather and loadout, but its generally in this area.

[CybrSlydr]

Wow, you guys sure aren't shy to use the burner then. I struggle to get to 25k without using it.

[Frederf]

Optimum cruise is usually ~28kft moderately heavy and gets super high when light 36kft+. That's if you want to fly like an airliner. Combat considerations usually demand 300 KCAS minimum for maneuvering potential. Generally you want to cruise in the 0.82-0.88 range. Anything M0.9 and above is rather inefficient fuel use.

 

Max range is weight-based but usually about 250 KCAS, endurance 210-230. Above M.88 fuel penalty gets bad.

[Kayos]

I usually level off around 25-30k. AA only I will go higher.

[Dee-Jay]

Hi!

Normally, ... it depends on flight/package assigned FL (or blocks) in ATO/ACM's to respect Transit Routes/Transit corridors to the Hold or to the Feeder/Push point ...

But this is not simulated. So ... you take what you want.

Regards.

[CybrSlydr]

I had 2 120s, 2 9x, 2 GBU 10, 2 fuel tanks.

 

25k takes a while to get to.

 

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[Deano87]

How are you climbing? A good rule of thumb climb profile for the F-16 Is select MIL (max power without AB) pitch to maintain 400 knots up until the time the Mach meter reads 0.80 and pitch to maintain 0.80 mach. It can get you up there pretty quick without using an outrageous amount of gas. The key is to not the let the airspeed get low during the climb, AoA then has to increase and drag along with it, and before you know you’re staggering along making no progress.

[CybrSlydr]

How are you climbing? A good rule of thumb climb profile for the F-16 Is select MIL (max power without AB) pitch to maintain 400 knots up until the time the Mach meter reads 0.80 and pitch to maintain 0.80 mach. It can get you up there pretty quick without using an outrageous amount of gas. The key is to not the let the airspeed get low during the climb, AoA then has to increase and drag along with it, and before you know you’re staggering along making no progress.

Typically at 95ish% until I'm in the 250ish it's, level off and then climb once airspeed is up again.

 

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[Dee-Jay]

I had 2 120s, 2 9x, 2 GBU 10, 2 fuel tanks.

 

25k takes a while to get to.

 

Sent from my SM-N960U using Tapatalk

 

 

What is your climb profile? ... (how are you climbing => Speed/Mach?)

[Deano87]

Typically at 95ish% until I'm in the 250ish it's, level off and then climb once airspeed is up again.

 

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All climbs should be done at full throttle (Mil, not AB), that is the most fuel efficient way. Let the jet accelerate to 400 knots after takeoff, pull the nose up to hold 400knots IAS until the Mach reads 0.80 and then pitch forward to maintain 0.80 mach (ignore airspeed from then on).

[CybrSlydr]

All climbs should be done at full throttle (Mil, not AB), that is the most fuel efficient way. Let the jet accelerate to 400 knots after takeoff, pull the nose up to hold 400knots IAS until the Mach reads 0.80 and then pitch forward to maintain 0.80 mach (ignore airspeed from then on).

Will do, thanks.

 

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[Deano87]

That’s just a rough rule of thumb as well. You can play around with different speeds to see what works best for your load out. General clean aircraft climb at faster airspeed/Mach because they have less penalty of fighting against the drag of high speed.

 

Here are some book figures for a clean jet and a heavily loaded down jet. I picked somewhere in the middle and it works for me.

 

MIL Power

------------

Drag Index (DI) = 0:

450 KIAS until Mach 0.88

 

DI = 300:

300 KIAS until Mach 0.72

[regards]

I prefer low ( at least below radar) and fast over densed hostile area's.

I know, i'm an asshole but since it's a sim no-one gets hurt.

Hint: try to abuse las Vegas as a rally area, using the hotels and casino's as pylons.

[Bagpipe]

All climbs should be done at full throttle (Mil, not AB), that is the most fuel efficient way. Let the jet accelerate to 400 knots after takeoff, pull the nose up to hold 400knots IAS until the Mach reads 0.80 and then pitch forward to maintain 0.80 mach (ignore airspeed from then on).

 

Thanks for the info :)

[Eldur]

As a general rule of hoof, fly your fuel flow and just try to get a high speed (up to ~ 0.92) with minimal FF.

[Deano87]

As a general rule of hoof, fly your fuel flow and just try to get a high speed (up to ~ 0.92) with minimal FF.

 

Once in the cruise you mean?

[Frederf]

I had 2 120s, 2 9x, 2 GBU 10, 2 fuel tanks.

 

25k takes a while to get to.

 

Sent from my SM-N960U using Tapatalk

 

One can do this one by the book. That's a 137 DI (call it 140) and about 39klbs GW. We'll assume standard day. Burn about 350 lbs getting to MIL climb speed wheels up. The next part takes some iteration but to get up there is gunna take about 1300 lbs so let's assume 38klbs GW.

 

Optimum cruise is somewhere between 32,500' 33kft at 0.82M. MIL schedule (which isn't minimum fuel trajectory but is a small accepted penalty for timeliness) is 390 KIAS transitioning to M0.82. One should expect to burn about 9 lbs/nm once up there. That puts you no more than 480 KTAS and 4500 lbs/hr rate.

 

Now that's going a long long ways. If mission range is much less then cruise altitude comes down. 50nm = 10kft, 100nm = 20kft, 250 nm 28kft that kinda thing. And as always combat (or coordination) considerations dictate everything in combat areas. Saving fuel is of little help if you're unable to dodge a SAM surprise because you're cruising along at 250 KCAS unless you want to make the biggest possible fireball.

[CybrSlydr]

One can do this one by the book. That's a 137 DI (call it 140) and about 39klbs GW. We'll assume standard day. Burn about 350 lbs getting to MIL climb speed wheels up. The next part takes some iteration but to get up there is gunna take about 1300 lbs so let's assume 38klbs GW.

 

Optimum cruise is somewhere between 32,500' 33kft at 0.82M. MIL schedule (which isn't minimum fuel trajectory but is a small accepted penalty for timeliness) is 390 KIAS transitioning to M0.82. One should expect to burn about 9 lbs/nm once up there. That puts you no more than 480 KTAS and 4500 lbs/hr rate.

 

Now that's going a long long ways. If mission range is much less then cruise altitude comes down. 50nm = 10kft, 100nm = 20kft, 250 nm 28kft that kinda thing. And as always combat (or coordination) considerations dictate everything in combat areas. Saving fuel is of little help if you're unable to dodge a SAM surprise because you're cruising along at 250 KCAS unless you want to make the biggest possible fireball.

 

Wow, good stuff - thank you!

 

It's going to take a LOOOOOOOOONG time to get to those altitudes.

[JUICE-AWG]

You know, the gas is cheap in DCS. But if you need to go a far distance away, or need longer hang time in the air, then higher is better with a conservative cruise climb to altitude. But if radar threats or visual contrail concerns are a factor, medium altitude can help you extend your endurance and offer you a high "JOKER" fuel state. If you're doing something like a RED FLAG exercise, you will be assigned a block altitude to de-conflict with other traffic in the package. Set up your missions so you have a tanker track available off your orbit track if you are holding station between two or three waypoints and drop down at 50% of total mission start fuel for 3-5K offload occasionally on a 3-4 hour mission. Don't forget your piddle pack!

 

 

Remember, minimum shutdown fuel by AFI is usually 1,100 pounds, so you should be in the overhead at about 2K...that's probably why DCS set the default Bingo at 2,000 lbs.

 

 

Anyone know where I can get a burned jetfuel candle for my SIM Room?

Edited January 8, 2020 by =JUICE=

[Deano87]

Anyone know where I can get a burned jetfuel candle for my SIM Room?

 

No... but now I want one. That’s a GREAT idea. Lol.

[Dee-Jay]

Hi!

 

...that's probably why DCS set the default Bingo at 2,000 lbs.

 

Having the bingo alarm when you already reached the minimum fuel overhead the recovery airfield is non-sens. It is already way too late.

 

Bingo should be calculated and set to a value allowing a safe return from the furthest point of your track and land and with legal minimums fuel quantity after a divert from your recovery to your alternate.

 

This is the rough calculation I am using on another sim:

 

Simple and fast rough computation (only applicable for F-16):

- At "standard" drag factor (around 150) and 480kts GS:

 

- Below 5000ft = 20lbs/Nm

- Between5000 and 25000 = 15lbs/Nm

- Above 25000 = 10 lbs/Nm

 

More elaborated rough computation:

 

- If you are using a fuel rate value based on a clean configuration ... add 30% for each 100 points of drag factor.

- If you are using a fuel rate value based on a fuel rate at sea level ... subtract 10% for each 5000ft

 

BINGO = Req fuel from TGT to RECOVERY + Req fuel from RECOVERY to ALTERNATE + 1000

 

IIRC, the reason of the 2000lfb is just that it is the system default value.

 

 

Regards.

[CybrSlydr]

Thanks for the help - I can easily reach 30k + now that I follow the 400kts/.82M method.