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Post by jpvisser on May 14, 2006 21:13:21 GMT
w1.rob.com/pix/oops/289429_Gnow,this picture shows the fifth engine on a 747, but what interests me is the fact some guy below comments the DC8 had that provision too. so,my question: did it? cheers JP.
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Post by chris on May 14, 2006 21:46:25 GMT
I have a book on DC-8s which has a photo of an -8 with the fifth pod installed, so to answer your question, yes. Keep in mind, this was with the original P&W/RR engines, as I don't believe the CFM-56 could be "fifth-podded", as it would hang too low. I did find this on A.net as well: www.airliners.net/open.file/0457505/L/ Odd looking to say the least... Chris
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Post by aerofoto - HJG Admin on May 14, 2006 22:04:30 GMT
"YES MOST DEFINITELY" .... I concur with Chris on this !
The DC8 did have provision for a 5th engine transportation .... and so did B707 too.
Of course these weren't operating powerplants. It was just a practical means of ferrying engines between point A and point B when required.
On both DC8 & B707 these engines were normally contained within purpose designed aerodynamic capsules then fastened below the wing between # 2 engine and the fuselage .... unlike occasionally ocurred with B747 & L1011 5 engine operation which saw such powerplants carried in the same position but completly unconcealed.
Mark C AKL/NZ
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Post by chris on May 14, 2006 22:55:42 GMT
Now, I've never seen a DC-8 with a fifth pod in person, but I have first hand experience with United's 747-100s and JT9Ds. Here's what I remember on the subject. The way UA did it, either the fan had to be locked from turning, which I never saw done (nor do I remember what sort of locking system was used), or the first stage fan blades were removed completely and shipped in boxes in the bulk cargo pit, and a nose fairing was installed, so as to cover the core of the engine (but not the whole inlet). In fact, in that photo of the 747, it looks as though there is some sort of cover over the core part of the inlet, so I suppose GE and RR have similar requirements. The reason for this is when the n2 spool turns from the wind, the gearbox turns as well, and the oil pump will build enough pressure to keep the bearings cool and lubricated. But it takes a bit of airflow to get the n2 spool to windmill. The n1 spool, on the other hand, has the big fan in front connected to it, and spins with the slightest breeze, and those bearings would take a beating if it was allowed to do as it pleased, and the n2 wasn't spinning fast enough, or not at all. There is actually a section in the maintenance manual stating that if the aircraft was parked into the wind, and the windspeed was over a certain amount, either the aircraft must be moved perpendicular to the wind, or the fans must be kept from turning (but nobody ever worried about it). By the way, UA never used the fifth pod on their 747-400s, even though the aircraft had the hardpoints on the wing.
Chris
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Post by jpvisser on May 15, 2006 0:57:58 GMT
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Post by chris on May 15, 2006 1:06:38 GMT
"Affirmative" on the DC-10 as well.
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Post by garryrussell on May 15, 2006 1:43:47 GMT
And the VC 10 They were carried on the wing also in sealed pods. On D Maltby's VC 10 airliners the tailhook function will make the engine pod appear Garry
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Post by aerofoto - HJG Admin on May 15, 2006 4:57:54 GMT
WELL .... I'll be buggered ! Mark C AKL/NZ
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Post by Aldo Regozani on May 15, 2006 11:13:54 GMT
hey, that sounds like a feature for the next version of our DC8
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Post by jpvisser on May 15, 2006 12:33:42 GMT
well, i'm amazed! i'm gonna check my vc10 asap ;D
cheers
JP.
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Post by Tony Madge - HJG on May 15, 2006 15:54:40 GMT
Hey Garry I did not realise that happened!
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Post by garryrussell on May 15, 2006 16:28:17 GMT
Hey Tony
I'm beginning to wonder if anyone did! ;D Garry
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Post by n334aa on May 15, 2006 20:27:44 GMT
NEW DC8!!!!!!! ;D ;D ;D ;D WOOHOO...lol. Is it true? I always wondered about that in David's models...I thought it was a fuel tank or something. Didn't know it was an engine pod. Cool feature. Little more eye candy. So what other aircraft besides the "heavies" can carry engine pods? So far the: B707 DC8 DC10 B747 L1011 ...what else...?
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Post by garryrussell on May 15, 2006 21:39:15 GMT
Nothing now I would think
There are enough wide bodied freighters to send one out inside nowdays.
Also most of the undeveloped airfields are now developed and more spares are held arround the globe.
So there is just not the need there was and it wasn't never done frequently only when needed.
And or course modern engines don't fail so often and enougth power for a perfectly safe flight with one engine shut down to the nearest maintenance base.
So I doubt it is ever done now or has been for a while.
Garry
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Post by kevin on May 20, 2006 22:36:16 GMT
Interesting that the older jets used a streamlined fairing. Today's widebodies seem to carry the engine 'as is'. Is the fan allowed to rotate freely? How does this compare to an un-feathered prop, which will eventually drag the aircraft into the ground?
Kevin
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