Moderators: richierich, ua900, PanAm_DC10, hOMSaR
Woodreau wrote:Depends on the runway, atmospheric conditions not just weight
So it "depends"
pikachu wrote:B777-200LR @ 360 000 KG, full thrust.
Flap 15 - 167/174/178
B777-300ER @ 840 000 POUNDS, full thrust.
Flaps 15 - 175/185/190
Matt6461 wrote:pikachu wrote:B777-200LR @ 360 000 KG, full thrust.
Flap 15 - 167/174/178
B777-300ER @ 840 000 POUNDS, full thrust.
Flaps 15 - 175/185/190
What's your source? You're putting 65k lbs over MTOW on the 77W.
pikachu wrote:As Woodreau said... it depends. What does it depend on? Take off weight, flap setting, pressure altitude, and ambient air temperature.
Here are the speeds from the QRH for a B757-200.
Flaps 1: V1 176 Vr 179 V2 184
Flaps 5: V1 161 Vr 165 V2 169
Flaps 15: V1 154 Vr 157 V2 160
Flaps 20: V1 145 Vr 148 V2 152
Magman wrote:pikachu wrote:As Woodreau said... it depends. What does it depend on? Take off weight, flap setting, pressure altitude, and ambient air temperature.
Here are the speeds from the QRH for a B757-200.
Flaps 1: V1 176 Vr 179 V2 184
Flaps 5: V1 161 Vr 165 V2 169
Flaps 15: V1 154 Vr 157 V2 160
Flaps 20: V1 145 Vr 148 V2 152
Pikachu - The conditions are "Standard Day" meaning 59F, 29.92 Barometric Pressure and zero head wind. The only variable not accounted for is the flap settings. Is there a "standard" or default setting?
Thanks,
Magman
slcguy wrote:Starlion is correct, standard conditions is a base point,. Conditions, runway, terrain and other factors all play in. That's why most planes can't always take off at MTOW. The answer to your first question is still the same, at any given weight and configuration the airplane will still have set V speeds.
slcguy wrote:Yes Starlion, that is correct. As I said in my first post V1 may vary due to runway length. Basically the speed that you can stop if you abort or fly if you continue, where the stop and go lines cross is the normal V1. Aircraft weight. and braking power are factored in. Magman's original post is more concerned with VR.
Magman wrote:pikachu wrote:As Woodreau said... it depends. What does it depend on? Take off weight, flap setting, pressure altitude, and ambient air temperature.
Here are the speeds from the QRH for a B757-200.
Flaps 1: V1 176 Vr 179 V2 184
Flaps 5: V1 161 Vr 165 V2 169
Flaps 15: V1 154 Vr 157 V2 160
Flaps 20: V1 145 Vr 148 V2 152
Pikachu - The conditions are "Standard Day" meaning 59F, 29.92 Barometric Pressure and zero head wind. The only variable not accounted for is the flap settings. Is there a "standard" or default setting?
Thanks,
Magman
Magman wrote:Pikachu,
Thanks for all of your input. The purpose of my request is to improve some software. My company (http://www.aprconsultants.com) have mathematical models of several commercial aircraft. We simulate the aircraft performing a takeoff, landing etc on measured runway profile data to evaluate the runway's ride quality; finding and quantifying the effect of pavement roughness. The models predict the aircraft's response to the runway's profile data. We are looking to validate the rotation speed of our aircraft models. Unfortunately, Boeing and Airbus are not willing to share this information. Anyway, that's the background for my request.
Thanks,
magman
GalaxyFlyer wrote:And, basing your product on data from an anonymous web forum is hardly authoritative. You will have to cite sources and A.net posting isn’t likely to impress.
GF
Magman wrote:GalaxyFlyer wrote:And, basing your product on data from an anonymous web forum is hardly authoritative. You will have to cite sources and A.net posting isn’t likely to impress.
GF
You are precisely right. That is why I am seeking out charts and performance data - to see if anyone knows where I may be able to access this data as opposed to opinions.
Thanks,
magman