White Bars on Fuel Flow Gauges

[Strider21]

What do the white bars on the fuel flow gauges indicate? They aren't mentioned in the HB Manual or the A-model NATOPS. 

 

[Oozler]

Not an expert but I think the left tape is left wing and aft tank right tape is right wing and forward tank.

[Strider21]

Sorry, I probably wasn't clear. I want to know what the three white bars on the outside of the FF gauge (1 on the top left and 2 on the right) not the fuel flow tapes. Presumably they indicate some notional FF values maybe like the ticks on the AOA gauge. 

[Eagle7907]

Following….


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[Callsign JoNay]

Now I'm curious as well.

[Q3ark]

Nobody knows

[Lt_Jaeger]

I'm seeing it that way

 

Lower one : best endurance band - I use it in holding

 

Upper one : best range / climb.

 

Can't get it any better but bet there is a experience guy around who can explain it in one sentence. 

[Strider21]

6 hours ago, Lt_Jaeger said:

I'm seeing it that way

 

Lower one : best endurance band - I use it in holding

 

Upper one : best range / climb.

 

Can't get it any better but bet there is a experience guy around who can explain it in one sentence. 

 

I think it is something similar but would like to see a direct reference or explanation.  The top end of the upper band (11K) is around full MIL at lower levels and of course the FF gauge doesn't indicate true FF when the AB is used so I am not sure exactly how the bars are used or intended to be used. If you want best climb, cruise or max endurance you the set the AOA  not the FF? Best range vs best climb are different parameters. 

The bars are also not mentioned in the NATOPS but the NATOPs does discuss using AOA for setting performance conditions. 

 

Also it seems odd that the lower band is only indicated on the right. 

Edited September 7, 2021 by Strider21

[captain_dalan]

I most certain DON'T know, but similarly to @Lt_Jaeger up there, use the lower strip for loiter or cruise. The upper i don't pay any attention to at all.... 

[Strider21]

1 hour ago, captain_dalan said:

I most certain DON'T know, but similarly to @Lt_Jaeger up there, use the lower strip for loiter or cruise. The upper i don't pay any attention to at all.... 

 

Can you explain how you use it? Particularly considering loiter and cruise (max range?) are two different performance conditions. 

[Callsign JoNay]

3 hours ago, Strider21 said:

 

Can you explain how you use it? Particularly considering loiter and cruise (max range?) are two different performance conditions. 

Push throttles up until fuel flow is next to top bars for good cruise range? Pull throttles back to lower bar for good endurance?

[Strider21]

1 hour ago, Callsign JoNay said:

Push throttles up until fuel flow is next to top bars for good cruise range? Pull throttles back to lower bar for good endurance?

 

The upper White Bars range from around ~5500 lbs/hr to ~11000 lbs/hr and low band is from ~1100 lbs/hr to ~3100 lbs/hr. For setting optimum fuel flows these are huge ranges.

 

Above about 30,000 ft you won't even see fuel flows above ~5500 lbs/hr so you cannot even set the fuel flow in that range. And at 25,000 ft, a Full Mil throttle setting is at the very bottom of the upper White Bar range. Likewise at 25k when you can just enter the White Bar range you are still 4ish units of AOA away from best cruise speed. So the band doesn't seem to correlate with best cruise speeds. 

 

Your loiter time in the lower band ranges by a factor of ~3. 

 

Plus the AOA indicator already preciously allows you to set the optimum climb and cruise speeds at the appropriate tick marks. 

 

It is still unclear to me exactly what the White Bars are supposed to indicate to the pilot and I suspect unless there is some missing information it isn't optimum loiter or cruise fuel flows. 

 

[Callsign JoNay]

I was just joking. Yes, they represent significant FF ranges. I'm just as curious as anyone what they mean or how to use.

[captain_dalan]

17 hours ago, Strider21 said:

 

Can you explain how you use it? Particularly considering loiter and cruise (max range?) are two different performance conditions. 

I don't pay for the fuel, so pedantic isn't the way to go (for me).
Roughly speaking though, when loitering i try to keep the FF in the middle of the lower strip and when cruising, either at the upper end or slightly above it, depending on the altitude. Flew 3-4 sorties over the Caucasus mountains this way and still landed with plenty of fuel left

Not quite scientific, i know, but hey, it works for shooting bad guys! 

[PhantomCat]

Someone ping Ward Carroll. Maybe he can shed some light.

[Arew]

https://twitter.com/wardcarroll/status/1436376593073524736?s=21 

 

Ward said mounting clamps which is the most plausible theory so far.

[Strider21]

@Arew Thanks! I agree that sounds very plausible. Perhaps the art (texture) in DCS doesn't quite match RL. 

[r4y30n]

This photo shows those stripes on the TIT.

https://lh3.googleusercontent.com/proxy/IxWfGe0-UgGu1PTCEzX8Qw9IxrKxQ74rifjFoE1tuy_SnOWhgB4JjerdYIxBMBJEooT4YEY69ocxsX8ZdAckrA

This one doesn’t appear to have the stripes at all. Seems likely they’re clamps reflecting the light and shouldn’t be white.

[DSplayer]

On 9/11/2021 at 5:21 PM, r4y30n said:

This photo shows those stripes on the TIT.

https://lh3.googleusercontent.com/proxy/IxWfGe0-UgGu1PTCEzX8Qw9IxrKxQ74rifjFoE1tuy_SnOWhgB4JjerdYIxBMBJEooT4YEY69ocxsX8ZdAckrA

This one doesn’t appear to have the stripes at all. Seems likely they’re clamps reflecting the light and shouldn’t be white.

I think it's simply a texturing error on HB's part. Probably will be fixed with the EGT for the F-14B gets added in October.