Hi,

Can anyone comment on the TO performance of the 707?

Best regards,
Robin.

Hi,

Interesting comments.

I found that if I use 107% N1 for takeoff, that she seems to not use as much runway when fully loaded as I was expecting (I figure about 6000 ft).

Once airborne though I found that she climbs OK?

If memory serves (please correct me if I'm wrong!!), it is ~107% N1 for takeoff with an initial reduction to 101% at 500 ft and then climb out to acceleration altitude, where thrust is further reduced to 97% for climb.

FS EPR is broken. Using N1 figures above I get EPRs of 2.10 or higher.

Best regards,
Robin.

Do the charts you have quote N1 as well? Would be a good check to see what it is like if you fly the N1 instead.

You may be interested in this: http://www.skybrary.aero/bookshelf/books/552.pdf

Airport was Sydney, +27 °C OAT, wind 050@10 kts, RW34 departure.

Calculated Accelerate/Stop distance is 7600 ft, actual 9400 ft.

Best regards,
Robin.

I've just read the report you posted a bit. Interesting.

The transcript of the Cockpit Voice Recorder is interesting, the conclusions are too of course.

"Vee one!"

"(Sound of Power Levers hitting Stops)"
"(Sound of reverse thrust noise starts)"
"(Sound of full reverse thrust)"

Not as expected if you calculate V1 for good reason and state that you're already above it with calling out loud "Vee one!"

A doubt that the modern way of loosing an engine on the 4 engine driven planes will cause a Captain to stop the bird, even when still below V1 and even on the two engine machines I doubt that (being close to V1).

First rule is to "fly the airplane" and those modern rockets can take the loss of an engine but they still brake dramatically bad when at high loads and already having eaten some large amount of runway. So the danger of an overrun is very high while the lost engine usually can be equalized and does not lead to an unsafe flight and landing.

I've read reports that state that an engine wasn't lost, it just stalled and FADEC brought it back to live but was interfered by an unsure crew that interpreted the engine readings somehow wrong, concentrated on that lost engine instead of flying, shut the engine down although it would be functional again and then got into real problems because their aircraft already ran into some "extra power need situation".

I think they nowadays even train to be real calm if "engine fire" comes up as it could indicate a soon passing condition and thereafter everything returns to normal values or at least workable ones while the emergency shutdown would give you a definitely inop windmill at one wing.

The cost factor might be another reason for continuing takeoffs because the aborted TO causes huge wear on the undercarriage elements and especially the brakes. Again, when done at high gross weights.

You also need to cool those brakes down for a very long time if high gross weights had to be stopped to zero. I remember the Concorde (which had a very advanced braking installation, first carbon on commercial planes) had to pause for hours then, with the brake fans running!

But we have to be fair. It's so easy to be clever after watching some guys fail.
I've read some minutes, nobody annoys me, everything is calm, I'm sipping on my tea .. while they were discussing the FO's technique, suddenly heard "bang" (those stalls are loud) and then the warnings to come up.
So decision time was a very small value here and you have to train and train to fight the impulse of human beings to stop every machine when it has a malfunction. Seems to be our nature somehow.

Might be the reason for this loud "Vee one" is to counteract this tendency and to make clear to everybody, that "we will fly from now on, whatever happens".
As you see, strong impulse on stopping even for the professionals.

Just a side note regarding EPR gauges in the 707:

I once saw a cockpit-video on youtube of a 707 taking off. They pushed the throttles forward, but all the EPR gauges showed different readings (one didnt move at all), while the other gauges (N1, N2, etc.) showed similar readings.

So I can imagine, that the EPR-gauges in the 707 weren't accurate at all. Apart from that, the EPR-gauges in the CS707 move the same way as in the video, first they wont wake up to move, and as you push further and further the needles suddenly almost "jump" to high values. I love this feature!

I normally take off with a EPR of 1.9 to 2.1. For me, this is a pretty good setting, as she rotates and climbs nicely. And the 707 was a ground gripper, it needed loooooong runways to take off. And thats why Boeing built the 727, so they could take-off and land a jet everywhere else where there wasnt enough runway for the clunky 707.

MikaelJ wrote on Oct 8^th, 2010 at 6:47am:


707 has turboJET engines, modern jets have hi bypass turboFAN engines.  Jump in anytime Lou!

LOU wrote on Oct 8^th, 2010 at 3:57pm:


I assumed jet due to to the age and heavy smoke, I didnt know fan engines were available back then,  tks

The smoke was there because of how the fuel was burned. After the EPA made some clean air rules sometime in the 70's, Boeing came up with the smokeless burner can. Pilots had used the smoke to find the traffic. After the modification to the burner cans it was harder to see the traffic, plus I think there was just as much pollution as before, but you just could not see it!