Yes. Spoilerons tend to be good for planes that would have significant adverse yaw. We now have several rigid wing hang glider models that use them. As long at you’re flying in a positve G situation, they’ll work properly. In a negative G situation they’ll put the drag on the correct wing, but I think they might act pretty weird in how they affect the lift on that wing. As long as you do your barrel roll maintaining positve G’s spoilerons should work fine.
The 747-400 (and presumably the -500, -600 and -8 if they ever get built) is fly-by-wire.
Cite?
Does China Airlines Flight 006 qualify? They lost an engine over the Pacific some years ago when it lost an engine on autopilot and the crew erred in the restart. Certainly not the manner in which one wants to do one, to be sure.
It’s not entirely clear to me that it completed a roll. But perhaps I didn’t read it carefully enough. In any event, I hate it when that happens.
http://www.boeing.com/commercial/airports/acaps/7474sec1.pdf
It doesn’t seem to say much about the 747-400 being fly-by-wire elsewhere on Boeing’s own documentation so I suspect it may be only partially true - conventional mechanical actuators for some bits and electronic actuators for others.
http://www.boeing.com/commercial/777family/pf/pf_facts.html
A brief browse of some message boards suggests that the “fly-by-wire” in the B747 400 is to do with the autopilot technology. At any rate, Boeing aeroplanes do not override the pilot’s inputs the way Airbus ones do.
Patch said:
I don’t think that qualifies as a barrel roll. They rolled 90 deg, then pitched nose down, to complete the rest of the roll with nose down.
Note the plane took 5 gees and dropped 30,000 ft in 2 and a half minutes. Note that at 5 gees, the plane did sustain damage, including permanently deformed wings and rear stabilizer damage.
That would suggest that if a barrel roll could be pulled off with low gees (<2 gees), it should be successful.
IANAstructural engineer or aviator, but that makes sense to me.
As a matter of pure physics, a precise 1.0g barrel roll is possible. Assuming a hypothetical perfect aircraft, one that can accelerate at any rate along all 3 axes, and can rotate at any rate around the axes, then there will exist a combination of accelerations and rotations that will precisely counter gravity, while maintaining a 1.0g acceleration in a buttward direction for any path of travel an aircraft can make. The largest actual acceleration the aircraft will have to make is 2g in the positive z axis when the plane is precisely inverted, whereupon the pilot and airframe are doing 1g from gravity, and 1 from aerodynamic acceleration, and will only feel 1g buttward. Determining whether any ACTUAL aircraft can make the required accelerations and rotations requires more aeronautical engineering knowledge than I ever want to attain.
I disagree - but maybe we have to agree on terms. What exactly do you define as a barrel roll? In my mind any valid barrel roll is going to start and end in straight and level, unaccelerated flight. Somewhere in between there will be non-zero vertical velocity (i.e. the plane will be going up and/or down). Given these parameters I don’t think you can keep it to 1G (assuming for the moment that we don’t try and bring orbital dynamics into the picture).
You mean like this?
Edit: I guess I should have read the first page before posting…
I’m glad you linked it, Ale. The OP seems to have inadvertently omitted the link to the video.
That’s incredible, pouring iced tea during the whole process of the loop!
Nope. That is quite definitely not a 1G maneuver.
That is an example of a positive g manoeuvre, it is not an example of a 1 g manoeuvre. Anytime you pitch up away from the Earth whether it be during the entry to or exit from a loop, or barrel roll, or any other manoeuvre involving vertical movement, you must necessarily exceed 1g. This is true both theoretically and in practice. In theory, given the right aeroplane, you could have very low gs but it must always be more than 1.
Bob Hoover is a legend, but he cannot change the laws of physics.
I have diplomatic immunity from the laws of physics. Does that count?
1 g is 9.80665 m/s[sup]2[/sup], but gravity is less than this near the equator (and more near the poles), so you have some wiggle room. Even if you use the International Gravity Formula, which varies with latitude, there are regions of higher and lower gravity. Off the southern tip of India looks like a good spot.
If you’re going to nitpick why not use orbital mechanics? Just get the thing flying so fast that it’s experiencing only 1/2 G to begin with. But I think everyone but broomstick would easily recognize that this is not what anyone meant when they claimed a barrel roll is a 1G maneuver.
That’s a bit harsh. She may have been wrong on this issue, but she’s not an idiot.
If you want to roll an aeroplane with minimal g you should do a roll using the aircraft’s maximum roll rate. The g in a barrel roll is introduced by the pitching rather than the rolling, so the tighter you make the roll the less gs you’ll feel. The trick is to start with a high(ish) nose attitude (say 20 deg up), roll with full aileron and neutral elevator but allow the nose to drop through the horizon as you roll through the inverted position, this keeps the gs positive. You should end up in a shallow dive. Of course you still have to pull up to the initial high nose attitude, and you have to pull out of the resulting dive which means it’s still more than 1g. It’s basically an aileron roll, but there is a little bit of elevator use just to maintain positive g. What Bob Hoover did in that video was closer to an aileron roll than a barrel roll. The faster the aircraft’s roll rate the less pitching you need to do to maintain positive g, that’s where it’s difficult in an airliner, they have a slow roll rate so you’d need to accentuate the pitching more to keep the gs positive.
I’d be interested to see if someone can work out just how much sky you’d use doing a barrel roll at 250 knots with a 1.1g pull up.
Her comments to and about me were astonishingly innaccurate, and more than a bit harsh. Unfortunately, the rules of this forum prevent me from responding to the second part of your claim.