RB211s starting

[Capt. Greaseon]

Just thought the L1011 lovers would like this. If only all engines sounded like this on start!!!!



YouTube - L-1011 Engine Start Part 1 N700TS (Aircraft leaving Roswell and heading to Kansas City) 01-30-2010

Is is because the RB211 have three spools we get this deep sound when they start?

[barit1]

It's the combustor organ-pipe resonance, isn't it? And I'm amazed the EPA didn't make them control/capture all that unburned fuel!

[lomapaseo]

It's the combustor organ-pipe resonance, isn't it? And I'm amazed the EPA didn't make them control/capture all that unburned fuel!

It strikes me that if it were unburned fuel there would have been many incidents of toasted aft fuselages on L1011's. if it were to light off externally

I'll go with typical steam and smoke out of the exhaust until the smokeless combustor does its thing.

Any old hands on here like 411 and rampers who know?

[N1 Vibes]

Capt Greason,

I would suggest that the fuel system has previously been inhibited with something like Aeroshell 1. We used to use this in the test-cells, to preserve the delicate fuel components from corrosion, before engines went back to the customer for storage.

When you try to relight an engine for the 1st time that's been inhibited, the Aeroshell 1, which is actually a very thin 'oil', burns like they are announcing the new pope at the vatican. Until it clears from the fuel system you will get smoke like this and the engine will not fully 'fire-up', because the mixture is about 50:50 of oil to kerosene.

Hope this answers.

Best Regards,

N1 Vibes

[EW73]

I recall that when starting these RB211s, if you don't get that resonating sound, as you occasionally didn't, the engine would always go on to suffer from a stagnated start with rising EGT.

I always listened specifically for that sound, and if I didn't get it when I needed to, I closed the start lever, allowed it to run back down on the starter, then when stabilized, re-introduce the fuel/ignition, worked every time.
If I allowed it to continue to the stagnated indication, the resulting EGT would be much higher and would therefore take much longer to cool back prior to restart.

Did that for years in Air Pacific in those very nice (leased QF) 747-200s they used to run.

EW73

[gas path]

I too would go along with the inhibiting oil. I've also had the fire brigade come out on more than one occasion when someone has seen the smoke!. However with a protracted (hung) start like that even when it 'lit up' I guess it would warrant a look at the HPC stg 1 for a couple of bent blades!

[411A]

Any old hands on here like 411 ....

You called?
And ,yes to the following...

I recall that when starting these RB211s, if you don't get that resonating sound, as you occasionally didn't, the engine would always go on to suffer from a stagnated start with rising EGT.

and...

I always listened specifically for that sound, and if I didn't get it when I needed to, I closed the start lever, allowed it to run back down on the starter, then when stabilized, re-introduce the fuel/ignition, worked every time.
If I allowed it to continue to the stagnated indication, the resulting EGT would be much higher and would therefore take much longer to cool back prior to restart.

Spot on.
The unusual 'sound' is flame propagation in the burner cans, whilst starting.
-524B series, anyway.
Can't say about the other RB.211 varients....haven't operated those.

[Capt. Greaseon]

Thanks for the replies, all I can say it is by far my favorite sound in aviation. Wish there were more of them still around.

[rudderrudderrat]

Hi,

And I'm amazed the EPA didn't make them control/capture all that unburned fuel.

All that blueish white smoke is oil fumes. The original 211-22B had their "Labyrinth" oil seals made using IP bleed air. I'm afraid to say some were very smoky on start up (they were not really two stroke) but once IP air was available they stopped burning engine oil.

[Beeline]

I agree with rudderrudderrat, The fuel tanks must have been filled with inhibiting fluid for that long a wet cycle!

[Dengue_Dude]

Our SOP was to motor the engine to 10%N3 to motor that spool through a stall on each start.

Gave a characteristic noise akin to a rumble each start.

Is that the sound you mean?

That was on RB211-524 and -22Bs

[grounded27]

Love that triple spool sound, you can really hear (video did not capture the lower frequencies heard) all three spools humming as they catch up with eachother.

[Peter Fanelli]

You can keep your RB211 noise, this is how an aircraft engine should sound...


YouTube - Wright 3350 Radial Engine

[Swedish Steve]

All that blueish white smoke is oil fumes.

Well I tend to disagree.
When I started on the Tristar I worked in the Middle East. We didn't have masses of smoke out the back.

then I moved to Stockholm, and the TWA crews used to put the fuel/ign on at very low N3, and the smoke poured out. I have always thought it was unburnt fuel in the cold air.

Our SOP was to motor the engine to 10%N3 to motor that spool through a stall on each start.

That is what causes the smoke!.
After 6 years starting engines in BAH, we always ran the engine up to max N3, or at least 20pc N3, or we got a hot start.

In ARN we had a Tristar that only flew on weekends. So on Friday mornings we opened it up, and swept the snow out of the Nbr 2 intake and started it up. OAT around M10deg.It took about four minutes of starter motor before the starter cut out. Oil pressure off the clock high, and oil qty zero, and a fog bank behind us.

The problem with the -22 was that the fuel flow difference between no acceleration, and a stall was tiny. It seemed that we did mods to the start bleed system every 6 months. You never could remember which valve was controlled by which switch, and what the master sw did at the third detent. (except get you nearer to a hot start). With each new RB211 variant it gets better, and now the Trent 800 starts in seconds. (well 30 secs to idle).

[barit1]

With each new RB211 variant it gets better, and now the Trent 800 starts in seconds. (well 30 secs to idle).

...which is the norm for CF6.

[lomapaseo]

all this talk about the sounds an engine makes. Reminds me of the sound of the non RB211,s including the Pratts and GE's where after hearing the whoosh and the whistle of the start sequence you hear that satisfying whoomp as the burner lights and pressurizes the aft end of the machine.

Of course a less than satisying sound is the start sequence being energized by morons in the cockpit engaging the starter when you have your hands inside the fan on an engine. Turns out they were trying to get some airconditioning going on a hot day in MNL and hit the wrong switch. A couple of guys came rolling out of the inlet pretty quick

[Capt. Inop]

Of course a less than satisying sound is the start sequence being energized by morons in the cockpit engaging the starter when you have your hands inside the fan on an engine. Turns out they were trying to get some airconditioning going on a hot day in MNL and hit the wrong switch. A couple of guys came rolling out of the inlet pretty quick

With your experiece and knowledge concerning turbofan and turbojet engines i doubt you would put your hands anywhere near N1 stage unless any source
of bleed air was unavailable. Anyway, from the moment that you hear the starter and to the fan starts sucking in big objects there's plenty of time to get out of the intake and walk to a safe distance.

Dealing with aircraft engines on the line with anyone on the flightdeck, expect at least one moron flippin switches.

[grounded27]

With your experiece and knowledge concerning turbofan and turbojet engines i doubt you would put your hands anywhere near N1 stage unless any source
of bleed air was unavailable. Anyway, from the moment that you hear the starter and to the fan starts sucking in big objects there's plenty of time to get out of the intake and walk to a safe distance.

Dunno about modern high bypass engines but the JT-9 could start with the fan (N1) strapped, heard of the fan being held during a dry motor.

[barit1]

There have been cases of large fans started with N1 frozen (ice in the LPT, thermal lockup, etc.) and no harm done if it's only a short period, not above idle.

One potential concern is lack of seal pressurizing air drawn from a fan/LPC stage, thus possible oil loss; so such operation should not exceed OEM limits (possibly 30 seconds or so).

[Gas Bags]

There have been cases of large fans started with N1 frozen (ice in the LPT, thermal lockup, etc.) and no harm done if it's only a short period, not above idle.

One potential concern is lack of seal pressurizing air drawn from a fan/LPC stage, thus possible oil loss; so such operation should not exceed OEM limits (possibly 30 seconds or so).

Please enlighten us as to the OEM limits for the abnormal start you are referring to.

If I had such a start I would be extremely concerned and abort the start well before idle.

This is a windup surely.