JAGflyer
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747-300/400 Pod Compatible?

Mon Feb 01, 2010 8:26 pm

You don't see the 747s carrying 5th engines on the wing anymore. Is this because the -300 and -400 series do not feature the feature of carrying a ferry engine? Would this feature be worth putting on an aircraft, specifically on 747 freighters that operate on behalf of a passenger airline (EK, JL, DL/NW for example)? The last 5th engine 747s I've seen are from the early 1990s.

Is the ferry engine pod attachment still practical for use on today's modern 747s?
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kimon
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RE: 747-300/400 Pod Compatible?

Mon Feb 01, 2010 8:43 pm

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lowrider
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RE: 747-300/400 Pod Compatible?

Mon Feb 01, 2010 10:40 pm

With 3 engine ferry and the ability to ship any engine inside a 747 freighter, there is little need to pod an engine.
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Viscount724
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RE: 747-300/400 Pod Compatible?

Mon Feb 01, 2010 11:17 pm



Quoting JAGflyer (Thread starter):
Is the ferry engine pod attachment still practical for use on today's modern 747s?

I recall someone saying that 5th pod capability was an option on the 747-400. Two QF 744s below with 5th pods.


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cpd
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RE: 747-300/400 Pod Compatible?

Tue Feb 02, 2010 1:22 am

Quoting JAGflyer (Thread starter):
You don't see the 747s carrying 5th engines on the wing anymore. Is this because the -300 and -400 series do not feature the feature of carrying a ferry engine?


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It was more common on the older planes (such as the 300) but it still happens, just not as often. That's why all the SYD photographers rushed when VH-OJQ had the 5th pod installed last year.

Quoting Lowrider (Reply 2):
With 3 engine ferry and the ability to ship any engine inside a 747 freighter,

Thats fine if you want to use a freighter, but if you don't or one isn't available - the option is 5th pod ops, in this case, a QF flight departed with the 5th (good engine) to SIN where OJQ was stuck with the dead engine. Engine swap occurred, good engine for dead engine, then OJQ comes back with the new engine and the dead engine attached as the 5th one.

[Edited 2010-02-01 17:25:35 by cpd]
 
474218
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RE: 747-300/400 Pod Compatible?

Tue Feb 02, 2010 1:41 am



Quoting Lowrider (Reply 2):
With 3 engine ferry and the ability to ship any engine inside a 747 freighter, there is little need to pod an engine.


Why rent a freight (or pull one off the line) when you can install the spare pod on a revenue flight. Saves time and money.
 
lowrider
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RE: 747-300/400 Pod Compatible?

Tue Feb 02, 2010 3:31 am



Quoting 474218 (Reply 5):
Why rent a freight (or pull one off the line) when you can install the spare pod on a revenue flight.

Depends on where the spare engine is and if you have another 747 to pod it over on. I have carried a few 74 engines. I have also carried a 777 engine.
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rmm
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RE: 747-300/400 Pod Compatible?

Tue Feb 02, 2010 8:38 am

IIRC the CF6 was never certified for 5th pod op's. I'm not sure about the PW4000. QF's 744ER's do not have 5th pod attach points.
 
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747classic
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RE: 747-300/400 Pod Compatible?

Tue Feb 02, 2010 9:29 am

IIRC well the 747-100/200/300 were all equipped with a 5th pod attachment point. It's optional on the 747-400.
The speed was limited to M.78.

To actually use this 5th pod feature the airline had to buy this option from Boeing. It was then included in the relevant OM.

I never saw a CF6 5th pod operation, probably this engine type was not certified for 5th pod operation. The CF6 engine can be spit in 2 parts and transported internal in the cargo hold. However all CF6-50E2 powered 747-200/300's I operated were equipped with the relevant attachment point.

747 fifth pod operation is possible with P&W JT9D engines (747-100/200/300) and the RB211-524 engines (747-100B/200/300/400).

I have no knowledge about the 747SP 5th pod operation. ?
The need for 5th pod operation diminished with the introduction of wide body freighters and combi aircraft.
On the main deck the engines could be transported far more cost effective en immediately ready to install.
Only airlines with no freighters or combi aircraft (QF) are interested in this feature, because buying on short notice cargo space in an AOG situation can be very expensive.
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musang
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RE: 747-300/400 Pod Compatible?

Tue Feb 02, 2010 12:12 pm

BA didn't go for the 5th pod option on their 744s although of course used it on the -100/-200s. I'm told the RR engine cannot be transported in the hold even when dismantled. Engine reliability is so good these days that the occassional three-engine ferry or expense of a freighter are considered acceptable risks. (This from an individual in the maintenance department).

The speed limit is mentioned above, but does anyone have access to a CDL or ops manual supplement to tell us the fuel penalty, t/o weight limitation and other precautions?

I recall from the one I saw close up, that the fan and spinner were removed, spinner attach bolts hung in a little cloth bag in the cavity behind the spinner, exhaust duct covered by a streamlining cone and a flat plate with curved edge cross-section (like a frisbee) fastened over the front. This disc's diameter was less than that of the intake, allowing airflow through the bypass duct.

I was intrigued by how the unit was hung on the wing, the gap between the pylon and the lower wing surface, and how hard you have to look to see the attach hard-points when its restored to normal.

I look forward to a knowledgeable person adding to / correcting / elaborating on my recollections!

Regards - musang

[Edited 2010-02-02 05:18:25]
 
Tristarsteve
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RE: 747-300/400 Pod Compatible?

Tue Feb 02, 2010 1:53 pm

I had little involvement with 5th pods on B742. Took a couple off in BAH for BA, but that was about it. 5th pods need organising. The pod has to be fitted to the aircraft, and removed at the other end. This takes time and can be tricky on the ramp. It definitely does not help keeping the aircraft on schedule. But in the 1970s and 1980s with the severely limited 3 engine ferry capability of the B742, and the lack of freighters, it was a good option.
With the B744 the need dropped off. Except for Qantas, who live on an island miles from anywhere, most airlines found they could do without it. The B744 engines are much more reliable than the early JT9s so they don't fail so often, and the B744 has a very good 3 engine ferry range. BA will ferry a B744 back to LHR from anywhere except Australia. There they will loan an engine from Qantas for the return trip ( and remove it on arrival LHR). Even SIN-LHR can be done with only one stop en-route.

But I had a lot of involvement with the Spare Engine System (as Lockheed called it) or 3rd pod (as everyone else called it) on the Tristar. It was sold as easy to fit and use on scheduled flights. It was neither. It was very awkward to fit. After the first try, we always fitted it in the hangar, and allowed at least 3 hrs. The engine had to be positioned under the wing with the cowlings fitted (they did not go on afterwards, ask someone who found out the hard way!), between the landing gear and the Nbr 3 engine. There was not a lot of space, and you had to be within an inch or two or the chains would not attach.The pylon was fitted beforehand, then the engine wound up with some inbuilt jacks in the pylon.
The aircraft with a 3rd pod was limited to 270kias. This is slow, and because of this it could not operate BAH-LHR non-stop, and stopped in LCA for fuel. A 7 hr flight ended up at around 10hrs. GF tried in once on a scheduled flight, after that the flights were closed out as soon as it was known, and pax advised to rebook.
Removing the pod on the ramp was OK, took over an hour, but then you had to move the engine to the hangar, and the stand was not sprung, so it was much quicker to tow the aircraft to the hangar and remove it there. If the engine was serviceable it could be complete, if there was any doubt the fan blades were removed and a crude aluminium blank placed over the IP intake. The fan blades went into six big wooden boxes that went on a pallet.
We went through this procedure a few times, but only from BAH to LHR. We never used it for casualty engine changes. These were always two-engine ferried back to BAH to be changed at base. In fact GF only once performed an engine change away from LHR BAH and HKG (Haeco), and that was in JED. Bit strange that. We had an engine failure in JED in around 1977, and two-engine ferried the aircraft to BAH. This was tricky as the temp would not go down below the 34degC rqd for a direct ferry until 0400, then on the take off (first one for GF) the aircraft swung off the runway. By the time it was ready to go again, it was too hot. Went well the second night! As we were changing the engine in BAH, we had another engine failure on a different Tristar, and no engine, so ended up loaning an engine from SV, and two-engine ferrying the aircraft to JED for the change.
After a few 3rd pod operations, GF opened its own RB211 shop at BAH and changed modules instead. the 3rd pod gear was rarely used after that, it caused too much disruption to the operation.
 
lowrider
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RE: 747-300/400 Pod Compatible?

Tue Feb 02, 2010 4:12 pm



Quoting TristarSteve (Reply 10):
BA will ferry a B744 back to LHR from anywhere except Australia.

Out of LAX they will operate it as revenue.
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A342
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RE: 747-300/400 Pod Compatible?

Tue Feb 02, 2010 6:25 pm

Now the obvious question: Will the 5th pod be optional on the 748? I guess the answer is no, but I've learned to never say never!
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lowrider
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RE: 747-300/400 Pod Compatible?

Tue Feb 02, 2010 8:30 pm



Quoting A342 (Reply 12):
Will the 5th pod be optional on the 748?

For a price, Boeing will do just about anything you want to the plane. Its not like it would be groundbreaking work, so I imagine it would be available if a customer demanded it.
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Starlionblue
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RE: 747-300/400 Pod Compatible?

Tue Feb 02, 2010 11:48 pm



Quoting TristarSteve (Reply 10):
It was sold as easy to fit and use on scheduled flights. It was neither.

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jetmech
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RE: 747-300/400 Pod Compatible?

Tue Feb 09, 2010 7:41 am

Quoting Musang (Reply 9):
I was intrigued by how the unit was hung on the wing, the gap between the pylon and the lower wing surface, and how hard you have to look to see the attach hard-points when its restored to normal.

I found this wonderful photo as I was cruising around the database this evening. It shows a JT9 5th pod strut. The attachments to the wing and the top of the 5th pod strut itself are pretty much identical to the RR 5th pod.

http://www.airliners.net/photo/North...d=b50c867e0cedd7c7e327c48a7e4ae5d9

You can just make out the three fittings one is required to fit to the wing to enable carriage of the 5th pod. These three fittings are the P1, P2 and P3 fittings. The P1 fitting is the main fitting, and is a big "C" shaped hunk of metal. It is the forward most fitting, and attaches to the forward spar of the wing. The P2 and P3 fittings are much smaller, and bolt directly to the bottom wing skin. The P1 fitting takes almost all the weight of the 5th pod, with the P2 and P3 fittings designed to stabilise the pod and keep it pointing in the right direction.

In the photo, you can see the P1 fitting accessing the forward spar via a access hole in the lower fibreglass fixed leading edge panels. The P2 and P3 fittings are on either end of the horizontally orientated white beam. In the middle of the white beam is the end fitting of the cable winch which assists in lifting the 5th pod up to the wing. The main lifting winch is a multi-row chain which attaches directly to the bottom of the P1 fitting. Both winches are wound manually by hand to raise the 5th pod. The 5th pod is then bolted to the P1, P2 and P3 fittings to finish the installation.

You can see the access panel for the P1 fitting relatively easily when the pod is not fitted. The bolt holes for the P2 and P3 fittings are two small groups of four bolt holes arranged in a square pattern. They are usually fitted with blanking screws when the pod is not fitted.

Regards, JetMech
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musang
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RE: 747-300/400 Pod Compatible?

Tue Feb 09, 2010 2:07 pm

Hello jetmech.

I'm pleased you liked the pic. How satisfying, after all these years, to finally get the mounting explanation you provided. The winches/chain/cable you mentioned - are they installed internally when carrying the pod, or are the gears inside and the winch drive shaft inserted through an external hole?

Regards - musang
 
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jetmech
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RE: 747-300/400 Pod Compatible?

Tue Feb 09, 2010 2:48 pm

Quoting Musang (Reply 16):
The winches/chain/cable you mentioned - are they installed internally when carrying the pod, or are the gears inside and the winch drive shaft inserted through an external hole?

G'day Musang,

With the RR 5th pod set-up, the winches (gearboxes/gears/cables/chains) were built internally into the 5th pod strut itself, and are not visible from the external aspects of the strut. Two large crank handles were fitted to square drive adapters that were mounted flush with the left hand side of the strut, which allowed one to manually wind the winches. Nice photo BTW! Technical pictures are always the best!

Regards, JetMech
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Molykote
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RE: 747-300/400 Pod Compatible?

Tue Feb 09, 2010 3:21 pm

Quoting TristarSteve (Reply 10):
Quoting jetmech (Reply 15):

I enjoyed both of your posts very much. I, as one of the younger people in my work field, love hearing these things from people with experience on hardware that was either before my time or beyond my typical operating experience.
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747classic
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RE: 747-300/400 Pod Compatible?

Thu Feb 11, 2010 5:35 pm

I found a couple of very rare 5th pod 747-206B photo's on the KLM historic website (sorry, only in Dutch).
On the third picture is the entire set of special made boxes visible for storing all special equipment, needed for the 5th pod operation.
see : http://klmhistorie.forum2go.nl/5th-pod-operatie-op-de-b747-t96.html
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