last officer

what is the Vmcg and the Vmca of the 744 ?

at what bank angle the spoilers start to crack open?

at what bank angle would you scratch the engine pods at Vref and just before touch down?

what minimum distance do you need measured from the a/c nose forward to a possible obstacle to turn 180 degrees on the spot?

thanks

LEM

you mean at what control wheel deflection, not bank angle!

HotDog

VMCG, VMCA depend on A/C weight, pressure altitude and OAT. Spoiler assist for roll control is initiated at 10 degrees of control wheel deflection on the classic, probably the same on the 400.
You can expect an outboard pod scrape from a 6 - 7 deg. body roll, depending on LDG WT.
Minimum pavement width for a 180 deg turn is 142 ft. (Again for the classic.)

QAVION

"at what bank angle the spoilers start to crack open?"

At 8 to 14 degrees control wheel movement, the spoilers will begin to crack open (according to my 744 engineering training notes)

"what minimum distance do you need measured from the a/c nose forward to a possible obstacle to turn 180 degrees on the spot?"

At the moment, the only value I have available is for the distance from the cockpit, forward, with Body Gear Steering disabled, of 59 feet.

Hope this helps.
Regards.
Q.

last officer

thanks to everyone, I appreciate it!

regarding Vmcg: Vmcg is highest at high weight,so I thought it would be nice to know to have the Vmcg for maxtow,because then you never could get below with your V1. I have never seen a V 1 below 118 provided by the FMS, so could this be the highest Vmcg?

regarding spoilers: of course it is the control wheel who triggers the spoilers,I should have known that...

HotDog

V1 can never be below VMCG. If your TOW V1 is below VMCG, you adjust it to the VMCG value.
VMCG= minimum control speed on ground=rudder authority.

On a Classic 747, VMCG flaps 20 @ 320,000kg TOW is 142KN and so is the V1. At 340,000KG TOW, flap 20 V1 is 147KN with RB211-524-D4 engines. Sorry no data for 744, they do not need flight engineers.

Dan Winterland

On a GE pwered 744, VMCG with no derate is 125, with TO2 it's 117. Both SL at ISA.

The bank angle you would scrape a pod depends on the engine. More of an issue with a GE due to bigger pods.

The distance from the nose you need to turn inside an object to avoid hitting it (I take it this is what the turning Q is about) is 36.2 feet using 70 degrees nose gear angle.