Could you do this in a 747-400?
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Could you do this in a 747-400?
Came across this interview with Tex Johnston...707 Barrel Roll. He mentions how safe it is, why don't we see this at air shows etc?
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A well flown barrel roll is a 1 g manoeuver ie you are not pulling positive or negative g. As such their should be no stresses placed on the aircraft. An A320 for example is certified from -1g to +2.5g clean (0 to +2 with the flaps out), so a 1g barrel roll would be perfectly safe BUT I don't know any airline aircraft that are certified for aerobatic manoeuvers. As such, any attempt to roll an airliner would be viewed as a pretty reckless act by everyone from the manufacturer to the local aviation authorities so is highly unlikely to be seen at an airshow!
That said, I know of an old (WW2 vintage) ex instructor who is reputed to have rolled every aircraft he ever flew (GA only...up to Cessna 402/404 size)
Some of the aero-heads out there may be able to provide you with more info, but an aerobatic certified aircraft will certainly have to have demonstrated more than just a simple barrel roll, and will likely be rated to roughly -2g to plus 6g or better (I'm casting my mind back to C152 Aerobat numbers, but the mists of time are concealing the actual numbers from me!)
Tex Johnson is a legend, but from a time where such acts were admired rather than frowned upon. Doubt it would happen today.
Cheers
DC
That said, I know of an old (WW2 vintage) ex instructor who is reputed to have rolled every aircraft he ever flew (GA only...up to Cessna 402/404 size)
Some of the aero-heads out there may be able to provide you with more info, but an aerobatic certified aircraft will certainly have to have demonstrated more than just a simple barrel roll, and will likely be rated to roughly -2g to plus 6g or better (I'm casting my mind back to C152 Aerobat numbers, but the mists of time are concealing the actual numbers from me!)
Tex Johnson is a legend, but from a time where such acts were admired rather than frowned upon. Doubt it would happen today.
Cheers
DC
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A Barrel Roll is NOT a 1G manoeuvre!
Guys
A Barrell Roll is not a 1G manouevre! It IS a positive G manoeuvre- but to get the pitch rate to describe a "barrel" around the horizon requires more than 1G initially eg up to 3G depending on aircraft.
An AILERON Roll on the other hand (if flown correctly) can be a 1G manoeuvre
Gliderboy
A Barrell Roll is not a 1G manouevre! It IS a positive G manoeuvre- but to get the pitch rate to describe a "barrel" around the horizon requires more than 1G initially eg up to 3G depending on aircraft.
An AILERON Roll on the other hand (if flown correctly) can be a 1G manoeuvre
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Buster
Properly executed they would hardly spill a drop!...Coffee that is you filthy minded readers
J
Properly executed they would hardly spill a drop!...Coffee that is you filthy minded readers
J
Last edited by J430; 31st Mar 2007 at 23:45. Reason: spelling after wine induced post!
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Dunno about barrel rolling a non aerobatic a/c but my late Father looped an Airspeed Oxford and lived to tell the tale!!
Knew a bloke in PNG who claimed to have looped a BN2 and tried to convince me to attempt same. My reply cannot be posted here but it was along the lines of .....Get
!!!!!!!
Knew a bloke in PNG who claimed to have looped a BN2 and tried to convince me to attempt same. My reply cannot be posted here but it was along the lines of .....Get
!!!!!!!
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Now an aileron roll is perfectly ok for any aircraft if performed correctly but Pinky a loop is an entirely different story. The bottom of a loop puts high stresses on the tailplane and will stretch the underside skin and should only be done in aerobatic type aircraft as their tailplanes are beefed up to withstand it.
There are old pilots and bold pilots but no old bold pilots.
There are old pilots and bold pilots but no old bold pilots.
As mentioned above, yes you could barrel-roll a 747 no probs.
It's a positive but low-G manoeuver and well within the factory limits of the 747.
FWIW the China Airlines 747-SP that did the high-dive years ago pulled about 5G's on the recovery, so they're plenty strong.
The avionics probably wouldn't be too happy about going inverted though.
It's a positive but low-G manoeuver and well within the factory limits of the 747.
FWIW the China Airlines 747-SP that did the high-dive years ago pulled about 5G's on the recovery, so they're plenty strong.
The avionics probably wouldn't be too happy about going inverted though.
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If you fly a barrel roll properly it would only be about 1 G. There are two times when you can pull more than 1 G, firstly uring the intial pitch up prior to rolling over and the other, when your attitude ends up too low upon the exit of the roll. We should ask Bob Hoover this question.
Last edited by JimmyReeves; 1st Apr 2007 at 02:13. Reason: Grammatical errors
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guys... A proper roll has to be only around 1G because if it were more or less than 1G this couldn't happen...
http://www.youtube.com/watch?v=Xp2Uc9XvmjY
http://www.youtube.com/watch?v=Xp2Uc9XvmjY
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This is why physics is a requirement at most airlines. Even high school physics.
You wouldn't have a bunch of pilots who think you can change direction (accelerate) without applying a 'g' loading to the aircraft.
Ok, you're right, it's a 1 'g' barrell roll.....
You wouldn't have a bunch of pilots who think you can change direction (accelerate) without applying a 'g' loading to the aircraft.
Ok, you're right, it's a 1 'g' barrell roll.....
Sure it could be higher then 1g. The cup would sit in the same spot, the liquid would pour, only thing is stuff would feel a little heavier. That applies all the way down to almost 0g....after that it gets a bit weird.
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Messiah; I am well aware of the stresses involved in aerobatics!
Hence my reply to the 'urger' concerned, which was !
Hence my reply to the 'urger' concerned, which was
!
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I still haven't exactly understood why that guy can pour a drink upside down.
And yeh, actually I think you would be changing the value of 'G' if you're rolling because you're still changing direction and therefore accelerating.
Edit
I think the centrifugal force has a lot to do with it.
And yeh, actually I think you would be changing the value of 'G' if you're rolling because you're still changing direction and therefore accelerating.
Edit
I think the centrifugal force has a lot to do with it.