767 roll rates

[BoeingBoy]

Many of us who fly both 757 and 767 know that the 767 rolls very swiftly in comparison with it's junior. Frankly a 'flick of the wrist' will easily transport most G&T's into the nearest walls.

However to settle a technical question that I have been asked does anyone have any reference as to what the roll rate of the 767 actually is. I can't find out by applying full aileron with passengers on board (without making the daily's anyway) so was wondering if any of you sim instructors or someone with a reference to such figures would happen to know.

At present I am estimating 20deg a second.

Thanks in anticipation.

Captain Dave Barrington
First Choice Airways

[Old Smokey]

Dave,

Talk to your 'Tech' people who maintain the simulator/s. For simulator software creation, and for simulator acceptance by the relevant authorities, the aircraft manufacturer supplies the simulator maker with control response data. This data is held by the Technical/Maintenance personnell for ongoing fidelity checks. This is the "real" control response data that the simulator tries to emulate. It doesn't always reproduce it exactly (rarely in fact) but sufficiently close to suffice for pilot training.

Be alert that tests made in the simulator will be approximate, extracting the control response data that the simulator is trying to emulate will be accurate "real world" figures.

Regards,

Old Smokey

[Charles Darwin]

I fly both types as well, and have often wondered about this as well. But the answer is perhaps simple.
Mou might just be right that the 767 has a slight bettter roll rate. But notice one thing. The wheel on the 767 has a 45° maximum deflection, each direction, while the 757 has 90°. So, for the same input on the wheel you are actually giving 100% more aileron deflection. The result may well be that we get the illusion that the 767 is quicker about. The fat one has active outboard ailrons below 250 but I really never notice any change in response. But then I guess we´re not supposed to.

[BoeingBoy]

Thanks for the replies.

I was aware of the wheel displacement issue but I guess what I am gettting at is a way of measuring the difference in 'muscle effort' to get a certain amount of bank to occur in the same time.

I am sure we would all agree that the 767 is finger light whilst the 757 requires you to have eaten spinach for breakfast to get round the corners!

I'll check with our sim providers first.

BB

[Mad (Flt) Scientist]

While the Qualification Test Guide data for the sim will have flight test gathered data for roll rate, it may not have MAXIMUM roll rate conditions in terms of speed, weight etc., since the intent of the data package is to ensure that the sim is a good training representation, not an engineering design tool.

You're probably looking for full control input data at Va (anything faster may well break something) and I doubt that's in the data package.

[BoeingBoy]

What I'm trying to gauge is what roll rate you would get if you were to input full aileron at anything from V2 through to say 300 knots?

Not something one can do with pax on board! Well, once maybe!

[Paul Wilson]

Found this Flight test report for the 767-400ER which said for 1/2 control wheel deflection a roll rate of 15 deg/dec was observed, how that compares to a 757 or a non 400ER I have no idea.

We entered an arbitrary working area into the Honeywell Pegasus FMC and set up for some flight maneuvers northwest of Moses Lake. The first was a check of roll rate in bank-to-bank rolls from 30 degrees to 30 degrees at ˝ wheel deflection. Flying the clean airplane at 350 knots, bank-to-bank took 4 seconds, for a roll rate of 15 degrees per second. Here is where a sharp control input initiated an aeroelastic response from the airframe. A later check of this same maneuver with flaps 30 at Vref=136 gave a bank-to-bank time of 6 seconds, or a roll rate of 10 degrees per second. This excellent response at slow speed in the landing configuration is another indication of the exceptional handling qualities of this airplane.

[john_tullamarine]

What I'm trying to gauge is what roll rate you would get if you were to input full aileron at anything from V2 through to say 300 knots?

.. don't know that I'd like to do that .. consider what Va style considerations imply ..

[BoeingBoy]

John, me too!

Paul, exactly what I was looking for. Thanks so much for your time.

Dave BB