sudden
Posts: 3934
Joined: Fri Jul 13, 2001 5:20 pm

L-1011 Startup.

Fri Oct 19, 2001 8:09 pm

I really like the L-1011 and what I wonder is:

When do startup, it sounds like it will not work. It takes so long, and then BOOOM!
And the smell you can never take for anything else then a Tristar.
How come it is like this with the L-1011?

Thanks in advance!
When in doubt, flat out!
 
Ratzz
Posts: 196
Joined: Mon Sep 27, 1999 6:58 pm

RE: L-1011 Startup.

Sat Oct 20, 2001 4:00 pm

You forgot the huge amount of smoke from each engine during startup thanx to the amount of unburnt fuel in the engines....
 
sudden
Posts: 3934
Joined: Fri Jul 13, 2001 5:20 pm

RE: L-1011 Startup.

Wed Oct 24, 2001 4:46 pm

No one that can help me out with this question!?
When in doubt, flat out!
 
musang
Posts: 788
Joined: Sun Apr 08, 2001 4:11 am

RE: L-1011 Startup.

Wed Oct 24, 2001 7:29 pm

Never operated L1011s but I know what you mean from years of hanging around ramps as a despatcher and pilot!

The start process is the same as just about any other turbine engine; the core section is spun to a certain RPM, the fuel is introduced, then ignited. The "Boom" you speak of is simply the fuel suddenly burning. The same process can be heard on any other engine if you're in the right place.

Large fans like RB-211 have correspondingly heavy rotating machinery, which takes more time to spin up than, say, a tiny 146 engine, which is why it takes so long and keeps you in suspense.

Some turbines are started by electric starter motors, some by forcing compressed air through the engine from the APU or an external Air Start cart. If its air started, the hissing of the escaping air often masks the sound of ignition.

Anyone know whether the RB-211 is air or electric start?

The characteristic start behavior of the L1011's RB-211s is therefore due to the exact timing of fuel on, followed by ignition, which results in more fuel being in the back of the engine than the ignitors can immediately deal with, bearing in mind the slow rotation at that time. Interesting that RR powered 747s don't make the same sound. Or put out the same smoke.

The sound must be simply the acoustics of the cowling and the hot section exhaust design.

But I repeat, I've no history with the type or its engine, just thought I'd offer the above until an RB-211 mechanic provides the expert answer!

Others with interesting start noise are BAC-111s and Tu-154s!

Regards - Musang
 
charliecossie
Posts: 408
Joined: Wed Oct 10, 2001 5:17 am

RE: L-1011 Startup.

Wed Oct 24, 2001 8:15 pm

Musang:
The 747/RR does make smoke!
The 211 is a 3 spool engine so has a lot more metal to get rotating than a CF6/JT9. Starting is slower because of this. Standard procedure when starting a 742/RR at BA is to use both ignitors but the Tristar only uses one ignitor. That's why the Tripe makes more smoke (usually). The 747 sounds the same as a Tristar (same inlet and exhaust).

The 1-11 makes such a strange noise because it doesn't have a starter as such. The CSD is driven (by air) which then turns the engine.
 
sudden
Posts: 3934
Joined: Fri Jul 13, 2001 5:20 pm

RE: L-1011 Startup.

Wed Oct 24, 2001 9:19 pm

Thanks for the replys!
Have done headset alot of times on Tristars and other jets, but the BOOM is so much more on the Tristar.
Can't say I don't enjoy it!
When in doubt, flat out!
 
CPH-R
Posts: 6064
Joined: Thu May 03, 2001 5:19 pm

RE: L-1011 Startup.

Wed Oct 24, 2001 10:07 pm

I can only agree on the 744's making smoke too.. Of course, this being in the right conditions. I once had a couple of hours to kill in Seoul Kimpo (during winter) and everytime the 744's started their engine, smoke was everywhere.
 
sudden
Posts: 3934
Joined: Fri Jul 13, 2001 5:20 pm

RE: L-1011 Startup.

Wed Oct 24, 2001 10:34 pm

If it's winter I can understand it, cause it's often deicing fluid that makes it smoke more.
When in doubt, flat out!
 
charliecossie
Posts: 408
Joined: Wed Oct 10, 2001 5:17 am

RE: L-1011 Startup.

Thu Oct 25, 2001 1:20 am

Sudden:
Nonsense.
 
sudden
Posts: 3934
Joined: Fri Jul 13, 2001 5:20 pm

RE: L-1011 Startup.

Thu Oct 25, 2001 4:55 pm

Charliecossie......

I was told that when it's winter and the fluid gets in to the engine, and when they start up the engine there can be alot more smoke caused by this. Didn't say I was correct!
When in doubt, flat out!
 
musang
Posts: 788
Joined: Sun Apr 08, 2001 4:11 am

RE: L-1011 Startup.

Sat Oct 27, 2001 6:22 am

'Cossie - I must admit I was thinking of the 744s, we don't see many RR 742s at LGW any more. I agree, the 742 is essentially the same installation so will behave similarly!

What differences between the D4 and H2 affect its start characteristics?

Regards - Musang
 
charliecossie
Posts: 408
Joined: Wed Oct 10, 2001 5:17 am

RE: L-1011 Startup.

Sun Oct 28, 2001 7:20 am

I'm only a fixer so can't detail the precise reasons.
The later engines must be more efficient at starting - they're quite happy to start on one ignitor, for example.
The combustion chamber doesn't fall to bits either.
Finally, the FAFC is able to control starting fuel flow rather better.

That's my story and I'm sticking to it.

GIven the right conditions, though, and the G/H can do a pretty good impression of a 22B.
 
TimT
Posts: 168
Joined: Sun Jun 03, 2001 1:38 pm

RE: L-1011 Startup.

Tue Oct 30, 2001 9:49 am

Ok, here's the thing. The RR on the L-1011 is started with compressed air either from the APU or a start cart. Starter is attached directly to the main gearbox forward side, right. Always. Engine is turned to about 20% N2 with the ignitor(s) armed, fuel is introduced and when it lights off you can get a boom, thump, woooff, or whatever else you could call it. The smoke is produced by oil. The RR uses labryinth seals that are held in place by bleed air into the bearing cavity. As the air pressure decays, (loose fit, long time shut down,etc.,) the seal ring can come "unstuck" from it's mating surface and leak into the cavity. I've seen totally dry RB's dump a quart out of the front bearing just by moving the fan (N1). If the oil gets to the combustion chamber or behind the turbine it's going to burn and presto-- white smoke.
 
KCLE
Posts: 673
Joined: Fri Feb 23, 2001 11:03 am

RE: L-1011 Startup.

Tue Oct 30, 2001 11:32 am

During my time spotting I've seen a generous amount of RB.211 powered CO 757-200's of CO, and do they sound like an L-1011, and how come they don't smoke on startup?
 
musang
Posts: 788
Joined: Sun Apr 08, 2001 4:11 am

RE: L-1011 Startup.

Thu Nov 01, 2001 3:17 am

Thanks for the definitive answer TimT.

So its oil smoke.

Regards - Musang
 
TimT
Posts: 168
Joined: Sun Jun 03, 2001 1:38 pm

RE: L-1011 Startup.

Thu Nov 01, 2001 4:03 pm

The RB211 is a rather funny animal. The L-1011 version of that engine is totally (IMHO!) distinctive. I've never seen or heard another RR engine, including the BA747's (RR powered) moan and groan like the L-10. The CO 757's are powered with RB211-535C or E versions. Practically the same engine, I suspect the thrust rating is different, and they may have a different bearing cavity seal in them.
Not to start a flame war, but not all of the L-10's smoke on start either. One carrier we tested engines for would absolutely not accept an engine that smoked- startup or shutdown.

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