Tom12 From United Kingdom, joined Dec 2005, 1078 posts, RR: 14 Posted (7 years 4 months 3 weeks 4 days 10 hours ago) and read 12690 times:
I was just talking to a friend and he was saying that the 747 can fly belly-up for 12 seconds so i was wondering, is this true and what happens after the 12 secs are over?
Thanks
"Per noctem volamus" - Royal Air Force Bomber Squadron IX
Matt72033 From United Kingdom, joined May 2005, 1617 posts, RR: 4 Reply 1, posted (7 years 4 months 3 weeks 4 days 10 hours ago) and read 12678 times:
Quoting Tom12 (Thread starter): was just talking to a friend and he was saying that the 747 can fly belly-up for 12 seconds so i was wondering, is this true
i sure as hell wouldnt wanna be the one trying it!
Quoting Tom12 (Thread starter): and what happens after the 12 secs are over?
MDorBust From , joined Dec 1969, posts, RR: Reply 2, posted (7 years 4 months 3 weeks 4 days 10 hours ago) and read 12680 times:
Get any plane high enough before turning turtle and you can fly it belly up for quite a while. Feed in enough forward stick and you might just keep it that way for a good deal of time. Of course, I don't recommend doing so with pax on board.
Just get it right side up again before the altimeter winds down
Dw747400 From United States of America, joined Aug 2001, 1244 posts, RR: 1 Reply 5, posted (7 years 4 months 3 weeks 4 days 8 hours ago) and read 12565 times:
I'd imagine it would have more to do with the aircraft's systems than anything else. Aerodynamically, most aircraft can maintain inverted flight (not necessarily level flight, but controlled flight) for a short period. But I have no idea how a 747s fuel system, hydraulics, etc. would react to being upside down.
Starlionblue From Hong Kong, joined Feb 2004, 15870 posts, RR: 66 Reply 7, posted (7 years 4 months 3 weeks 4 days 8 hours ago) and read 12553 times:
Quoting Dw747400 (Reply 5): I'd imagine it would have more to do with the aircraft's systems than anything else. Aerodynamically, most aircraft can maintain inverted flight (not necessarily level flight, but controlled flight) for a short period. But I have no idea how a 747s fuel system, hydraulics, etc. would react to being upside down.
Exactly right. The aerodynamics are not a big problem. That's mostly about angle of attack. The question is if the fuel can still be pumped to the engines, if said engines are properly lubricated, if all the pax have a brown trouser moment...
Quoting Ptrjong (Reply 6):
Quoting Pelican (Reply 4):
Didn't Tex Johnston double barrel role a 707 prototype?
Googling his name seems to indicate he did. Well, I'd love to see photos of that.
I bet plenty of people on A.nut have the footage. I used to but inadvertently deleted it . There's also a pic taken from the plane which shows the engines "on top" of the wing. That picture is here: http://www.historylink.org/essays/output.cfm?file_id=4270 but it's been put up "upside down". You can see the ground is at the top of the frame.
Tex only kept his job because he was basically the flight god at Boeing at the time. The boss was not happy.
Note also:
- Role is something for actors. Roll is something for planes.
- A barrel roll, when properly executed, means the plane is subjected to about 1g towards the floor of the plane throughout the manoeuvre. So there's no undue stress on the airframe. Thus a barrel roll is not aerodynamically the same as flying inverted, or even of a level roll.
- The plane in question was the 367-80, the common ancestor of Boeing Models 707 and 717 (the old 717 that is better known as C-135).
"There are no stupid questions, but there are a lot of inquisitive idiots." - from Citadel by John Ringo
Nudelhirsch From Germany, joined Oct 2003, 1438 posts, RR: 20 Reply 10, posted (7 years 4 months 3 weeks 4 days 6 hours ago) and read 12493 times:
I might be wrong on this: it could be possible, as long as enough lift is provided, requiring appropriate thrust, fuel injection, ...
The thing I would be more worried about is: the roll itself. I am quite sure that a big airliner like the 747 cannot survive the roll without stalling.
Starlionblue From Hong Kong, joined Feb 2004, 15870 posts, RR: 66 Reply 11, posted (7 years 4 months 3 weeks 4 days 5 hours ago) and read 12453 times:
Quoting Nudelhirsch (Reply 10):
The thing I would be more worried about is: the roll itself. I am quite sure that a big airliner like the 747 cannot survive the roll without stalling.
For a barrel roll, it's not a problem since positive Gs are maintained. For a level roll it's all a question of turning the plane and the wings generating lift. While a 747 is very large so are it's control surfaces. Why should a 747 stall when rolled if the roll is performed properly?
"There are no stupid questions, but there are a lot of inquisitive idiots." - from Citadel by John Ringo
PhilSquares From , joined Dec 1969, posts, RR: Reply 12, posted (7 years 4 months 3 weeks 4 days 5 hours ago) and read 12448 times:
I can tell you it will do it in the simulator. It's really not a very difficult maneuver. It's all 1 G flight and the engines and fuel do just fine. The IRS doesn't like it too much.
The other issue is speed. If you do it around FL180 with about 320-350KIAS you don't dish it out on the bottom of the barrel roll.
FL1TPA From United States of America, joined May 2004, 258 posts, RR: 0 Reply 13, posted (7 years 4 months 3 weeks 4 days 2 hours ago) and read 12373 times:
The Discovery Channel interviewed Tex Johnston for a special on Commercial Aviation a few years back. He recalled rolling the 707 for the press and onlookers by Boeing Field. He said as long as there's at least 1G on the airframe at all times so that the fuel and hydraulic pumps aren't uncovered, you can roll any plane.
That's a barrel roll, not an extended 12 second period; and on a 707, not a 747.
I seriously doubt it.
FL1TPA
"Looks like I picked the wrong week to stop sniffin' glue."
Boeing Nut From , joined Dec 1969, posts, RR: Reply 16, posted (7 years 4 months 3 weeks 3 days 17 hours ago) and read 12270 times:
Incorrect. Any fixed wing aircraft could perform this manuever in the hands of a skilled pilot. It would raise hell with the structural integrity of the aircraft though. I understand that this was the case of the Dash 80 as it developed a flutter in the rudder after the famous barrel roll.
Sustained inverted flight is of course, another matter.
Starlionblue From Hong Kong, joined Feb 2004, 15870 posts, RR: 66 Reply 17, posted (7 years 4 months 3 weeks 3 days 17 hours ago) and read 12262 times:
Quoting Baflyer (Reply 15): So if a barrel roll can be done all at 1G does this mean that the trolley dollys should be able to continue with the meal service!!!
Of course
I'd like to see the a 747 do a hammerhead. That's aerobatics!
"There are no stupid questions, but there are a lot of inquisitive idiots." - from Citadel by John Ringo
Tod From Denmark, joined Aug 2004, 1682 posts, RR: 3 Reply 18, posted (7 years 4 months 3 weeks 3 days 16 hours ago) and read 12227 times:
Quoting FL1TPA (Reply 13): He recalled rolling the 707 for the press and onlookers by Boeing Field.
Actually about 5 miles, over Lake Washington during Seafair.
The photo in reply 14 is looking west toward the Beacon Hill and Ranier Beach neighborhoods.
CitationJet From United States of America, joined Mar 2003, 2229 posts, RR: 3 Reply 19, posted (7 years 4 months 3 weeks 3 days 4 hours ago) and read 11995 times:
Quoting Pelican (Reply 4): Didn't Tex Johnston double barrel role a 707 prototype?
Yes, here is a link to the 707 prototype roll movie, and an interview with Tex...
2H4 From United States of America, joined Oct 2004, 8950 posts, RR: 62 Reply 20, posted (7 years 4 months 3 weeks 3 days 4 hours ago) and read 11983 times:
AIRLINERS.NET CREW HEAD DATABASE EDITOR
Quoting Boeing Nut (Reply 16): Incorrect. Any fixed wing aircraft could perform this manuever in the hands of a skilled pilot.
2H4 From United States of America, joined Oct 2004, 8950 posts, RR: 62 Reply 22, posted (7 years 4 months 3 weeks 3 days 4 hours ago) and read 11967 times:
AIRLINERS.NET CREW HEAD DATABASE EDITOR
Quoting Starlionblue (Reply 21): Ha! Good one. Well if the blocks in the software were removed it would be possible.
Dw747400 From United States of America, joined Aug 2001, 1244 posts, RR: 1 Reply 23, posted (7 years 4 months 3 weeks 3 days 3 hours ago) and read 11958 times:
Quoting Boeing Nut (Reply 16): It would raise hell with the structural integrity of the aircraft though. I understand that this was the case of the Dash 80 as it developed a flutter in the rudder after the famous barrel roll.
I'm curious what caused this. Being a 1G maneuver, I'd imagine the strain on the airframe wouldn't be that significant, unless the airspeeds used were excessive. Perhaps the lateral forces against the tail?
HAWK21M From India, joined Jan 2001, 31201 posts, RR: 58 Reply 24, posted (7 years 4 months 3 weeks 3 days 1 hour ago) and read 11882 times:
Quoting Boeing Nut (Reply 16): I understand that this was the case of the Dash 80 as it developed a flutter in the rudder after the famous barrel roll.
Any Details.
regds
MEL
Think of the brighter side!
25 Jetlagged: All you have to do is switch of both FACs and you are in roll direct law. Then a barrel roll would be possible. Something not so far mentioned above
26 Jafa39: No one expects the Spanish Inquisition!!!!!
27 Backfire: One of Airbus' chief test pilots once confidently told me that the A310 could perform a 360-degree roll, and then became very coy when I asked how he
28 2H4: That's good stuff! Reminds me of the time I was talking with a former U-2 pilot. I asked him how high he's flown. Right away, he starts to answer, "O
29 HAWK21M: For those who are not Familiar with the term "Spanish Inquisition" Wonder why.Did he know something & not want to share or He realised he was trapped
30 Starlionblue: Indeed. But I think Jafa39 was referring to this particular instance: http://en.wikipedia.org/wiki/The_Spa...ish_Inquisition_%28Monty_Python%29 Here'
31 Boeing Nut: I'm not sure. I've just heard stories that there was a chronic anomoly with the rudder after the roll. I said pilot, not flight manager.
32 Ptrjong: Yeah I was quoting Python too Thanks for the photograph. So some people are saying barrel rolling a big jet is no problem, and that there need not be
33 BartiniMan: Most, if not all, pilots flying large aircraft these days would not want to lose their jobs and licenses.
34 Starlionblue: He wasn't the only one. But this one had a more "Darwin catches up with you" approach: http://aviation-safety.net/database/record.php?id=19640715-0 N
35 Kevinl1011: He must be made of tougher stuff! Bring in......BRING IN THE COMFY CHAIR!!!! There was a China Air 747SP that supposedly rolled, how far over is not
36 HAWK21M: " target=_blank>http://en.wikipedia.org/wiki/The_Spa...on%29 Wow Another one Thanks for Sharing. Cant find those pics. regds MEL
37 Ptrjong: Put her in the comfy chair! Poke her with the soft cushion! Sure, but some pilots - I was thinking of military tanker crews - would have tried it if t
38 PhilSquares: First of all, you're not alone. It's not as if you're flying a fighter and "accidently" fly too low during low level. Should anything go wrong you're
39 EGTESkyGod: You can do anything you like on Flight Sim, even in an Airbus! A300 Beluga is always funny....
40 Starlionblue: As PhilSquares says, airliners are not certified for aerobatics. The typical exception is stalls for training and test purposes. Yes, intentional sta
41 Stratofortress: Inverted for 12 seconds seems a little far fetched. Why 12 seconds, and not 11? Do engines quit after 12 sec? Even then, you could always pitch down (
42 Meister808: Here's some pics: ..oh yeah... it's been repaired . Apparently there were a few extra degrees of dihedral added in the spiral dive, though, that make
43 ConcordeBoy: Perhaps not that model... but the SeattlePI (and they're usually pretty accurate and non-sensationalist) alluded to several Boeing pilots receiving d
44 Starlionblue: Also, as I mentioned before, there's really nothing in the aerodynamics of an airliner of any size that would hinder it from rolling. The limitations
46 777236ER: If the placarded structural limit is 2.5g then the load limit is probably about 3-3.5g for gust protection. It'll survive this without permanent defo
47 Starlionblue: Just reread the first post. My immediate response (well, I have had two glasses of fine wine) would be "it blows up into a ball of flame!!!" Honestly
48 FLY2HMO: A bit O.T., but I found that Boeing even has the picture up for sale, it's funny how they proudly display this picture now, when back then Boeing top
49 MX757: The Air Force barrel rolled a B-52 40 years ago just to see if could do it. It did, and they cracked the main wing spar in the process. Luckly the ai
50 Starlionblue: Wouldn't this mean the pilot did it wrong? With 1g towards the floor of the aircraft the whole time there shouldn't be any unusual stress.
51 PhilSquares: First of all, any reference for that???? Secondly, if the maneuver is done correctly, that won't happen. As a UPT instructor (T-38) it was very commo
53 Starlionblue: UPT? Is the T-38 as much fun to fly as it looks? As PhilSquares says, a correctly executed barrel roll will not stress the aircraft in an unusual man
54 PhilSquares: Undergraduate Pilot Training (USAF) It's more fun than it looks!!!
55 TheSorcerer: They had a clip of him doinh it on that program on Discovery Wings, Flying heavy Metal with the Iron Maiden Lead singer. Looked cool Dominic
56 Kevinl1011: Ok...here it is. The link below pretty much documents what happens to a 7four pushed beyond design limits. This is one of the most incredible aviation
57 MX757: Nope. This was back in my Air Force days when I first heard it. My MX instructor, who was formerly a B-52 crew chief, told me while I was in tech sch
58 HAWK21M: Amazing link. Thanks for Sharing. regds MEL
59 Cedarjet: Tex Johnston wasn't the only Boeing pilot to roll a 707 - a friend of mine who was an MEA 707 flight engineer in the 60s and 70s said it used to happe
60 YYZYYT: not a 747 of course, but Alaska 261 flew inverted for a while according to report... IIRC, the roll was intentional to try to maintain level flight i
61 Starlionblue: Fuel would still reach the engines as long as the fuel pumps work or suction works. On a MD-8x, you can't gravity feed anyway since the engines are ab
62 Kevinl1011: If the pick up tube is at the bottom of the tank. Wouldn't it suck air?
63 HAWK21M: What did the Official report qoute as cause. Isn't the Fuel pickup line a flexible type,similiar to the Tank Vent line. regds MEL
64 DALMD88: In 94 there was an attempted roll in a B52 at Fairchild AFB. It resulted in the loss of the aircraft with three deaths. http://www.simradar.com/Featur
65 Starlionblue: Good point, but this could create problems in turbulence as well if the tank is almost empty.
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. There's also a pic taken from the plane which shows the engines "on top" of the wing. That picture is here: 
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