Vref - Slatted v Non Slatted Wing

[Guptar]

Comparing G650 v Global of similar size

What's the typical Vref of a G650. How does that compare to the slatted wing of the Globals.

is the added complexity & weight of the slat system worth it. It seems that most largish jets are being designed with fixed leading edges.

is there any significant differences in handling qualities between the two jets in take-off and landing configuration.

[josephfeatherweight]

The G650 achieves an amazingly low Vref for a non-slatted wing - certainly no more than 10 kts faster than a Global for the same weight.

[Guptar]

Well, one reply. Pprune has certainly changed. 10 years ago one would ask a question and you would get a dozens or responses in a matter of hours from people who really knew their subject. Those times are long gone. No experts around here any more.

[Jarema]

Hi,

Most of the time Vref on G650 is about 118kt (about 6000lbs fuel load, 6-8 pax). Vapp is +5kt and is more than sufficient. No need to add extra for wind unless its really gusty.

[Klimax]

Hi,

Most of the time Vref on G650 is about 118kt (about 6000lbs fuel load, 6-8 pax). Vapp is +5kt and is more than sufficient. No need to add extra for wind unless its really gusty.

Yeah, rule of thumb you can do 110kts + payload and fuel. 6000 lbs is a comfortable arrival fuel with 118kts Vref as mentioned. Don't know about the Global, sorry.

[BizJetJock]

Global 6000 at 62,000lbs landing weight Vref 114kts. That's a similar loading depending on the empty weight of your aircraft.

[josephfeatherweight]

Dreadfully sorry to disappoint you, Guptar.

[DCThumb]

Global take off performance, in the wet, is significantly better than a G650!

[GlenQuagmire]

Ref on the Global is typically between 110 and 115. We fly ref and dont add anything unless conditions dictate.

[Klimax]

Global take off performance, in the wet, is significantly better than a G650!

Wow, that's awesome.

[TheWrongTrousers]

Well, one reply. Pprune has certainly changed. 10 years ago one would ask a question and you would get a dozens or responses in a matter of hours from people who really knew their subject. Those times are long gone. No experts around here any more.

PPRUNE....experts 🤣🤣🤣🤣🤣🤣🤣 Probably because 10 years ago this site was used by professionals primarily.

[DCThumb]

I’ve not flown both but have spoken to guys who have!

The 650 is nicer to fly on approach as it is much more responsive in roll - the Global can feel a bit wallowy at times!
This May be down to the slightly higher approach speeds, but much more likely to be that the Gulfstream wing is much stiffer. The Global wing is very flexible and gives a much more comfortable ride in the cruise...

If you want detailed perf comparisons, I have perf calculators for both types.

[His dudeness]

Well, one reply. Pprune has certainly changed. 10 years ago one would ask a question and you would get a dozens or responses in a matter of hours from people who really knew their subject. Those times are long gone. No experts around here any more.

So you ask a specific question about 2 types that are not exactly "Volkscrafts" - not 5 of em on every airport - that would require a person to answer it correctly to have flown both and then you whine about no answer ?

[His dudeness]

PPRUNE....experts 🤣🤣🤣🤣🤣🤣🤣 Probably because 10 years ago this site was used by professionals primarily.





A 2015 joiner..?

[GlenQuagmire]

Ask this question 10years ago and I suspect there would have been no answers at all because there werent a lot of G650s 10 years ago

[mystere-falcon]

you should compare global vs GV-550 if you want to compare slatted vs non slatted Vref, with the FBW the 650 has probably a Vref=1.23 instead of 1.3

[His dudeness]

with the FBW the 650 has probably a Vref=1.23 instead of 1.3

Our C680 has a Vref of Vs * 1,23 and certainly no FBW....

[Jimbo Pyne]

Aircraft with slats/leading edge devices are certified to 1.23 Vs = REF as opposed to 1.33 Vs = REF for those with just flaps, under CS-25.

That will help massively with performance figures....

As for the thewrongtrousers, I'm sure that more than one person has changed account on here at some stage! :}

[His dudeness]

Aircraft with slats/leading edge devices are certified to 1.23 Vs = REF as opposed to 1.33 Vs = REF for those with just flaps, under CS-25.

That will help massively with performance figures....

As for the thewrongtrousers, I'm sure that more than one person has changed account on here at some stage! :}

Our C680 has a Vref of Vs * 1,23 and certainly has no slats/LEDs....

[Mad (Flt) Scientist]

The question of 1.23 VSr vs 1.3 Vs for the minimum speed for Vref depends on the amendment standard of the rules at the time of applying for cert, plus any issue papers that may have shown up. It's got nothing to do, as has been stated, with any specific design feature (slats, FBW, whatever)

Note that this is only ONE of several minimum criteria for Vref. It doesn't always follow that Vref is set at this specific minimum

[Jet Jockey A4]

The question of 1.23 VSr vs 1.3 Vs for the minimum speed for Vref depends on the amendment standard of the rules at the time of applying for cert, plus any issue papers that may have shown up. It's got nothing to do, as has been stated, with any specific design feature (slats, FBW, whatever)

Note that this is only ONE of several minimum criteria for Vref. It doesn't always follow that Vref is set at this specific minimum


Agreed... the Global’s Vref speeds are actually artificially high and could have been lower, thus the use of only 10 knots added to wind corrections on approach.