Boeing 707-320C
 

Hi everyone, I have a question.
On the Boeing 707-320C (with JTD3 motors) the outer port wing nacelle pylon has a straight top compared to the inners. This appears to be only on the port side and not the starb. Anyone know the reason why it's just the port side?

Thanks.

Three turbocompressors for pressurisation. Explained by the late 411A here:

https://www.pprune.org/tech-log/1499...ml#post1582306

Hi Bazzarius.Engine pylons 2,3 and 4 contain a 'turbo compressor '-this is an engine bleed air powered air pump supplying air to the air-conditioning packs-when the first generation jet airliners came into service bleed air from the engines wasn't allowed to go straight into the cabin as there were concerns about contamination.

Thankyou. My apologies I hadn't realised that the subject had already been raised. Anyway, mystery cleared up.

And 30 years later, the person who'd decided that said 'told you so'

Just for completeness, it was not just the -320C, but the -320B as well. While we are on the subject the 720B generally only had turbo compressors on the inners.

No apologies needed, not something I knew (or perhaps had forgotten) and every day is indeed a school day.

However there are some 707-320C's that were built as all-cargo (such as those for Pan Am 707-321C)
and those built for AA (707-323C's both Pax and all-cargo) had TC's only on engines #2 and #3.

Also AA's 707-323B's also only had 2 TC's.

the 707-138B had 3 TC's

Same for the CV880, IIRC.

I seem to remember a VIP 707 with 4 TCs, Maybe Saudi royal flight.

The photo's of the BOAC B707-436 with RR Conway engines seem to show 4 TCs.

I've flown in a Boeing 707-338C back in the early-1970s on two separate occasions.

I also twice flew in a Douglas DC-8-52.

Somehow, flying on international routes was much more fun back then.

Today it is like a journey in a bus which flies, and crammed-in too. You just want it to end.

I had never noticed the difference in the Number 1 pylon before! :(

https://cimg4.ibsrv.net/gimg/pprune....0d9a43274c.jpg

I did a fair bit of lfying in the back of 707-300's. they were pretty good but they were cramped, especially width wise, the storage was poor and who can forget the pull down movie screen at the front ......

Every aircraft I've flown since on long haul has been a very significant improvement

Interesting. Flew in many 707s, mainly to and from Africa and cannot ever recall movie screens.I disagree with you about them being cramped, there was much more room than today's awful experience at the back end..

They were pretty cramped width wise (737 is the same fuselage isnt it) but they definately had far more leg room pitch 32-34 being very common. And they were so so noisy especially the 400 series coneway powered and the non fan P&W 300s .

I prefered the DC 8 so long as you got a window seat by a window and of course neither came close to the VC10, which prompts me to anwer the question why did the 707s have turbo compressors and not the VC10. As I recall the DC 8 had them under the cockpit giving the airfcraft a sort of odd toothy look

Maybe they were right about the cabin contamination though

OK can we now play a game of spot the difference with other aircraft? Spent time making noise recordings of competitors engines (as you do) and never ever noticed the odd man out!

[QUOTE=why did the 707s have turbo compressors and not the VC10. [/QUOTE]


VC10's had Godfrey screw compressors in the wing root fed by air from a small intake in the wing leading edge, what I cannot remember is how the compressor was powered.

Evening Sandringham,

I believe the Godfrey compressors were fitted above the engines and not in the wing root. I only worked on the VC10 as a BOAC apprentice so stand to be corrected. I recall that the compressors were mechanically driven by a shaft from the main engine gearbox.. I believe the air conditioning units were fitted in the wing root. I used to test the Godfrey blowers when working in the BOAC 'component test house' - on one occasion a blower actually blew up on test after the two parts of the compressor touched (there was only a few thou clearance between what we called the mangles) - it was a mess. Only we Brits could design such a thing and actually fit it to a passenger airliner. We also used to test the turbo compressors as fitted to the B707 - a much simpler and more effective design in my opinion. Anyway a bit of thread drift for which I apologise.

Back on thread. As far as turbo compressors fitted to B707 variants - when I worked in the BOAC hangers all B707-436's and 336's had 3 turbo compressors fitted to engines 2,3 and 4 whereas all B707-320's (they were foreign operators) had 2 turbo compressors fitted to engines 2 and 3 only.


Kind regards
Exeng

I wonder why the 707-436 had the same TC fairing on all 4 engines but only had 3 TCs fitted. Was it a style thing to make it look symetrical?

exeng,

You are correct. The VC10 had four engine driven Godfrey Blowers, one on each engine driven through a gearbox.

Well that depends, as now, on the airline. Of course we paid a lot more in real terms than today tho for absolute discomfort the 1 across seating in a slave 747 took some beating. Luckily only a few airlines went that way

Presumably they rapidly went bust. :O

The -436 nose cowls were all manufactured the same with the TC intake an integral part of the whole engine intake ring assembly so one must have been blanked although I cannot remember that, the JT3D engine intake was just the ring with the TC intake a separate thing installed when the TC was there or just the fairing if not.

https://cimg4.ibsrv.net/gimg/pprune....3b153cd1a.jpeg

Movie screens on the 707 were commonly retrofits, and so not all had them. I think the first BOAC ones were their last two bought new after their first 747s (with movies of course) which came along for the new London-Moscow-Tokyo route. US operators, particularly American and TWA, seem to have been the pioneers. I guess there were a number of different airline specs rather than a Boeing standard.

Even charter-config 707s were better than today's economy layout, especially what gets fitted as standard now in 787s, which I refuse to book again long haul.

All correct. The Godfrey compressors were fitted at the 10 o'clock position on each engine (looking forward), driven be a quill shaft from the internal wheelcase. The airconditioning system had two refrigeration units in the wing roots with associated inlets, and the rest of the pipework and such was in the vapour cycle bay adjacent to the wing roots in the fuselage, between the aft end of the FWD freight hold and the pressure bulkhead that sealed off the forward end of the wing cutout in the fuselage.

Just to add, the first in-flight movies were (inevitably) on TWA, given their longstanding commercial relationship with the film industry which Howard Hughes developed for them - I think he was still substantially involved financially with the airline in 1961, when this started, and inevitably on the prime movie industry route, New York to LA. I think at first there was only one screen, which avoided any synchronisation issues, and it was only shown in first class, which for a long period with TWA on this route was something of a film industry private club. Amazingly the tradition still continues with TWA's successor, American, on the same route, with custom-outfitted A321s with an oversize first class cabin, and all the commercial contacts still in place from a dedicated American team in LA.

The difference is, if you correct for inflation and such, what you spent for a coach ticket 50 years ago would probably get you a first class seat today - probably with some left over to pay for your Uber to/from the airport. This despite the cost of fuel going up much faster than inflation.
~45 years ago my dad bought me a coach ticket from Seattle to Washington DC so I could join my parents when they were there curtesy of the company he worked for. The price of the ticket was roughly equal to what I was paying for a years tuition and fees at college at the time...:eek:

Odd, I find it the complete opposite. 707's, DC-8's, VC10's etc were all extremely cramped, narrow and noisy. By comparison the latest Boeing and Airbus wide bodies are FAR more comfortable, quieter and so much more roomy. I've even flown economy in an Etihad A380 and found it to be extremely comfortable, even when full.

Maybe my aged memory is fading but I recall seat pitch at the back end of a typical 707 was 34 inches. On the so called improved wide body experience today the seat pitch is no where near as generous and certainly no where near the width either.

I would gladly sacrifice a bit of noise and lack of IFE for comfort.

But its the airlines who choose seat pitch and the one thing they know is that its the cost of a ticket that drives buyers. Enough airlines have been founded and failed on a model of Business only or more space in Economy. I'm afraid 95% of passengers go on price first, second and third. For the airlines sticking in a few Enhanced Economy seats is enough to cater for those who want a bit more space. But the extra price you pay is closer to the 1970's Economy price inflated for 50 years whereas Slave is still much the same price on the ticket as it was in 1970.

I think one of the factors aside from generous seat pitch that made things seem better back then was that flights were often not very full. Not the case today

Also some aircraft-DC9 MD80s were relaly nice if you got a seat in front of the wing (about 75% of them) on the two seat side , . 767 economy /economy plus if you had a window pair was very nice.
The 787 is , at elast in BA config horrible. The 380- easily the best although I haven't tried the 350 yet

This is a longstanding myth of those not from the commercial side. If it was true there would be no market for premium classes at all. Separately, we find carriers, particularly transatlantic ones, saying routes are unviable precisely because they have insufficient premium class ticket demand.

Perhaps - but back on topic the 707 proved the market for large scale, long distance travel - after that it was always bigger aircraft.

And worse service

Douglas on the DC8 appeared to have the cabin air intakes on the underside of the nose. Not sure how they got the compressing power away from the engines.

It is a few years since I last read this document, but you may be able to find the answer here: Gary Sommerville’s DC-8 experience. updated OCT 2018.pdf - Google Drive

Concerning early inflight movies with pull-down screens, I'm surprised no one has mentioned those staggeringly uncomfortable plastic tubes you had to stick in your ears. I would often forgo watching the movie just to avoid using them.

https://cimg5.ibsrv.net/gimg/pprune....c5ef8b95fe.jpg

https://apex.aero/articles/sound-tub...line-headsets/

The last time I used one of these was during an MRI, for the reason the article points out.

Oh god - I 'd managed to get those out of my memory..............

Slight drift.
On a BA 747-100 the movies were projected onto a screen at the front of each cabin and on one occasion, just as the film started, the displayed map image had a hole burn through it like the begining of the TV series Bonanza. I could see the screen in the next cabin forward and this was a different scene. Then there was sudden mild panic as smoke started to come from the projector as the film had jammed and caught fire. It was turned off and the fire went out before the cabin crew had got an extinguisher. The FE came back to have a look and we continued to London without the movie, just more drinks.