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Enthusiast Joined: Aug 01, 2006 Posts: 43 Status: Offline

I got a question to ask regarding the rate of fuel which is going to the engine.

What is the rate of fuel feeding to the engine from the Reservoir during AB?
I understand as the pilot goes from AB to MAX AB there's a range to the rate of fuel feeding to the engine. Does anyone know the range of values?

I've search through the Dash 1, 70GS and 80GS but still can't find the answer.

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I believe in augmentation, fuel does indeed travel through the reservoir, but does not go to the combustor, as the engine delivers through the afterburner rings, I believe 5 stages??? Count on increaseing your flow-flow X 3 of the mil power setting in full AB,... Very Happy

Elite 1K Joined: Apr 26, 2004 Posts: 1197 Status: Offline

70JG will give you the answer.

Enthusiast Joined: Aug 01, 2006 Posts: 43 Status: Offline

Purplehaze wrote:

70JG will give you the answer.

I've tried there but... can't find it. Sad

Fuel rate during AB will vary depending on things such as altitude, temperature. On a blk 40 saw around 24,000 at one point. It doesn't tell you what rate you should see in the TO's because there is no limitation to how much or how little fuel can flow, nor is there a limit to fluctuation in that setting.

Elite 1K Joined: Aug 19, 2004 Posts: 1090

IDCrewDawg wrote:

It doesn't tell you what rate you should see in the TO's because there is no limitation to how much or how little fuel can flow, nor is there a limit to fluctuation in that setting.

Not quite true. In the performance sections of flight manuals you'll find fuel flows for MIL and AB throughout the entire flight envelope. You're also given fuel flow data for a wide range of cruise conditions based on altitude, airspeed, drag index, etc. So you do have some idea of what fuel flow to expect... especially when it comes to MIL of max AB operation.

How about this...next time someone here does an AB run, make a mental note of what the FFT reads. That should make things easy enough. Evil or Very Mad

Elite 1K Joined: Aug 19, 2004 Posts: 1090

Fuel flow changes significantly with altitude and airspeed, so there would have to be quite a few mental notes. Smile

I was referring to a ground run. I'd hope there would be no altitude and/or airspeed changes there! Evil or Very Mad

Does it matter what type of engine we're dealing with too?

Elite 1K Joined: Aug 19, 2004 Posts: 1090

MechFromHell wrote:

I was referring to a ground run. I'd hope there would be no altitude and/or airspeed changes there! Evil or Very Mad

Well... that's a fairly uninteresting case and I don't think you'll find charts that go down to 0 Mach number... especially not for AB. But depending on what engine you're talking about, sea level static AB fuel flow would probably come out around 40,000 to 45,000 pph. That's just an estimate though. If you're still talking sea level but at Mach 1+, your fuel flow will be about twice as high for max AB. Fuel flow increases with airspeed much the same way thrust does (at least if we're talking about an AB turbofan or turbojet).

Elite 1K Joined: Aug 19, 2004 Posts: 1090

afnsucks wrote:

Does it matter what type of engine we're dealing with too?

The more thrust, the higher the fuel flow. The improved TSFC of the newest F100 and F110 models don't really do much in the way of balancing things out since they're able to produce much more thrust in certain areas of the envelope than older versions.

Here is a NASA T.M. on the F-16XL which should provide some unrestricted answers.

Ok guys and gals,
On the last burner run that I performed on a F110-GE-100B the fuel flow rate in the hush house located @ Hill AFB at approx 4965 Ft above sea level was approx (once stabalized) was at 34999 pph(pounds per hour) I don't know what the Pratt's put out but I would expect about the same flow rate in Max AB. Hope this answers your questions.

Raptor_One wrote:

IDCrewDawg wrote:

It doesn't tell you what rate you should see in the TO's because there is no limitation to how much or how little fuel can flow, nor is there a limit to fluctuation in that setting.

Not quite true. In the performance sections of flight manuals you'll find fuel flows for MIL and AB throughout the entire flight envelope. You're also given fuel flow data for a wide range of cruise conditions based on altitude, airspeed, drag index, etc. So you do have some idea of what fuel flow to expect... especially when it comes to MIL of max AB operation.

Since you have this knowledge, I assume you would know the rates. Would you mind posting what is expected. Perhaps the verbage it uses?

V/R
ID

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Rate which fuel is going to engine