Hi Alberto.

If you have downloaded the 707perf.zip from Avsim, in the 707performance2.pdf, there is a comprehensive table for the Vref of the 707.

If you haven't got it yet. Go and get it because it has great information in it. Search Avsim for 707perf.zip

Mark

I don't see the Vref landing tables in that 707performance2.pdf either?

It has 13 pages right?  Which one our you guys using?

There's a chapter "critical speeds" in the given documents from the Avsim file where you can read a wide range of data exceeding the shown placard (which still is a good source).
I don't know exactly the values for a correct calculation of the approach speeds then but I usually go with the always right 1.3 multiplier.

So if e. g. the aircraft has a given stall speed of 100 knots (which is an example of course) at the given weight and flap setting, multiply this critical speed with 1.3 and you have the save margin of +30.
You therefor aim towards 130 knots.
Winds might alter this value additionally.

As Airliners usually don't land like small General Aviation planes (big flare, near stall speed touchdown) but are flown onto the runway, this will give you a nice approach with a slow retarding throttle just before touchdown and very small pitch changes.
No need to get close to stall here.

I think we agree that those speeds and additional data would be best to come with the installer of the precious 707.
As seen on some other devs planes, a kneebord showing an overview of the most commonly used values would be fine too.
Maybe someone puts that into the wishes section of these forums.

I'm not good at handling html files but there might be a user around who collects some data and puts it into a kneebord file for everyone to load.
Friendly captains surely would appreciate this  

FYI

From the Boeing manual - this is for the 707, 727, 747, 767 & 757.

For every knot of extra airspeed add 50' to the landing distance. Ten knots fast would take 500' feet more runway.

Also, you would add 1/2 the gust to the VREF  Ex. - 250/15 G25 you would add 5 knots as a pad to the approach airspeed.

Lou

Yes if you flew at the Vref speed for the weight you had the right speed.

There was sufficient speed for normal landing at that weight and flap configuration.
Where pilots got in trouble was holding the plane off to get a smooth landing.
That's where the tail strike would happen or worse - go off the far end of the runway in ground effect. 

Lou

Hi,

@Lou: I thought you added half the steady and all of the gust?

e.g. 250@15G30, add 7.5+15 = +23 kts to Vth? IIRC max. correction is 20 kts, so it would be Vth + 20.

I'm trying to find some data I used to have on 707 perf.

Best regards,
Robin.