Heathrow mid 1970's

[ian531]

A shot taken by my dad in the mid 70's (we think)

Can anyone spot the subtle difference on this Pan Am B747 ;D




Ian

[Deleted]

Mar 16, 2010 19:35:59 GMT 1 ian531 said:

Can anyone spot the subtle difference on this Pan Am B747 ;D
Ian

I got one like that in the mid-70's, although this was a South African 747 at Manchester on a Heathrow wx diversion

[superian]

Unusual, why the 3rd engine on the port side?
Ian.

[Deleted]

Mar 16, 2010 19:58:32 GMT 1 superian said:

Unusual, why the 3rd engine on the port side?
Ian.

Being carried as a non-functioning external load for another aircraft.

Cheers,

Dave

[superian]

Thanks Dave, its a clever idea.
Ian.

[ian531]

We always knew the reason for the extra engine was a spare being collected or delivered.
But, does anyone know if the wing was specially adapted or could any B747 be converted to do this?
Also, why do we not see this anymore, surely engines are still moved around for repairs or replacement and this must be a much cheaper way than chartering a cargo flight?

Anyone got any more info?

Thanks

Ian

[northbynorthwest]

I flight planned a 747 carrying a fifth pod many years ago from Tokyo to Seattle. It was a 747-100 and from memory all the 747-100s and -200s were able to carry the extra pod under the left wing, which had a specially strengthened hard point. The engine had a plug fitted to prevent the fan blades from milling, and the increase in fuel burn was something like 30 per cent, as well as a speed and altitude restriction. I will see if I can track down any performance information, but as we have just stopped flying all -200s and moved headquarters, I fear all the information has been lost. It was indeed to move engines around the system rapidly, but it was seldom done except when the need was great. Later, the preference was to fly spare engines around on the freighters, even if it meant considerably rerouting the freighters in order to do it. I don't think the 747-400 has the hardened point on the wing to carry a fifth pod.

[Deleted]

Mar 17, 2010 5:41:51 GMT 1 northbynorthwest said:

I don't think the 747-400 has the hardened point on the wing to carry a fifth pod.

Seems they can carry a fifth engine:
www.airliners.net/photo/0289429/M/

Cheers,

Dave

[viscount]

I seem to recall the VC-10 could carry an external podded spare engine too. Remember in the late 60's/early 70's the engines on the B.747 were cutting-edge technology and way, way larger than anything else in civil aviation at the time. As a result engine failures in inconvenient places were to be expected. Today, not only are engines far more reliable, but also engineering back-up and spares holdings to cope with the unexpected are far more global.

[Deleted]

Mar 17, 2010 9:44:54 GMT 1 viscount said:

I seem to recall the VC-10 could carry an external podded spare engine too.

Indeed, see :


www.vc10.net/Technical/Images/G-ARVM_fifthengine.jpg

Details and another photo at:
www.vc10.net/Technical/oddities.html#EnginePod

Cheers,

Dave

[northbynorthwest]

Interesting shot of the -400 with the fifth pod to prove me wrong. That picture of the VC10 is amazing. I was able to retrieve some information about 747-100/200 5th pod operations. The planned fuel burn override was 25 percent more than standard, the maximum flight level was fl330, the max speed was mach .78 (versus the standard mach .84) - these were Northwest Airlines own limitations which would have been based on Boeing's own performance figures. For the flight I worked in 1990 NRT-SEA, there were no payload limitations, but westbound across the Pacific there would have been due to the headwinds. Probably the most interesting fact was that the pilots had to dial in a correction of two units of rudder deflection to the right in order to counteract the effects of a 20000lb load under the left wing. I also heard from a friend of mine who goes way, way back that Boeing did the same with the 707s too.

[ian531]

Thanks to everyone for all their posts. This has all been really interesting.

Thanks

Ian