# aerobatic 747's and DC-10's **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [August 29, 2003, 9:44pm UTC](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519 "2003-08-29T21:44:25Z")\ **Posts on this page:** 18\ **Page:** 2
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [September 2, 2003, 9:38pm UTC](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519/21 "2003-09-02T21:38:18Z")
> [@](#): > > \*Originally posted by Ancaster \* > \*\*‘Y’all watch’ this is said to be the last words of too many a pilot \*\* I’ll bet it’s more like “Y’all watch this!.. Hey, that’s strange-” ---
**Author:** ![picunurse](https://avatars.discourse-cdn.com/v4/letter/p/7bcc69/32.png) [@picunurse](https://boards.straightdope.com/u/picunurse)\ **Post date:** [September 3, 2003, 2:30am UTC](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519/22 "2003-09-03T02:30:01Z")
> [@](#): > > \*\*i don’t actually own a 747 but i suspect that really bad things will happen if you turn the engines upside down. they might just quit. \*\* Get a grip sailor, first, no one is claiming that any circus maneuvers are _approved_ for the big birds. They are able to do such aerobatics when called upon, that is during, and only during, flight testing & certification. I have this on very good authority (Members of a Boeing flight test crew) They do the testing in closed air space in remote areas of the country. Boeing purchased decomissioned Sac bases from the USAF, & the closed air space was part of the deal. They are mostly places you can watch your dog run away for 3 days. ---
**Author:** ![Herb\_Twoleaf](https://avatars.discourse-cdn.com/v4/letter/h/57b2e6/32.png) [@Herb\_Twoleaf](https://boards.straightdope.com/u/Herb_Twoleaf)\ **Post date:** [September 3, 2003, 4:35am UTC](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519/23 "2003-09-03T04:35:44Z")
Aren’t the fuel tanks and delivery systems on these things pressurized to ensure consistent fuel-flow in a variety of conditions and altitudes? Please forgive my ignorance regarding aircraft technology, but I would bet an inverted piston-engined plane would suffer from a lack of lubrication before a more sophisticated jet aircraft would die of fuel starvation in a similar position? Has anyone ever looped or rolled a helicopter? Thought I once saw a documentary where such a stunt was performed for a movie, though maybe it was all a hoax. ---
**Author:** ![timmerov](https://avatars.discourse-cdn.com/v4/letter/t/a698b9/32.png) [@timmerov](https://boards.straightdope.com/u/timmerov)\ **Post date:** [September 3, 2003, 5:54am UTC](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519/24 "2003-09-03T05:54:40Z")
“You may define “lift” to mean that it’s always in a direction relative to the plane’s attitude, but Cecil was talking about lift away from the ground.” glad we’re in agreement that cecil erred. ---
**Author:** ![amphalon](https://avatars.discourse-cdn.com/v4/letter/a/85f322/32.png) [@amphalon](https://boards.straightdope.com/u/amphalon)\ **Post date:** [September 3, 2003, 12:41pm UTC](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519/25 "2003-09-03T12:41:23Z")
I thought that those russian planes they use to get near zero-gravity did so by doing a long loop. Aren’t they big airliners? ---
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [September 3, 2003, 1:25pm UTC](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519/26 "2003-09-03T13:25:29Z")
So that was the whole point of the OP, that you think “lift” should only be used to denote force along the plane’s z-axis? Clearly, that’s not what Cecil was describing. ---
**Author:** ![5cents](https://avatars.discourse-cdn.com/v4/letter/5/46a35a/32.png) [@5cents](https://boards.straightdope.com/u/5cents)\ **Post date:** [September 3, 2003, 1:39pm UTC](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519/27 "2003-09-03T13:39:34Z")
> [@](#): > > \*Originally posted by amphalon \* > \*\*I thought that those russian planes they use to get near zero-gravity did so by doing a long loop. Aren’t they big airliners? \*\* The Americans use KC-135 (military version of the 707), the Russians use IL-76 (nothing really similar in the US, but think of a 707 with a wide body and high wing). Both of these are military transports, but in civilian trim would be considered mid-size airliners. Also, they aren’t doing loops, but rather parabolas. Think of throwing a ball. The shape it travels in is a parabola. The only difference with a plane is they don’t want to hit the ground, so they pull out of the free-fall. Doing the parabola, minimum Gs is close to 0 (over the top), maximum is about 2 (pulling out of the fall, starting next parabola). Nowhere near the 5 or 6Gs pulled by the AirChina 747 (and they were very lucky to come out of that alive!). ---
**Author:** ![JPdworkin](https://avatars.discourse-cdn.com/v4/letter/j/b19c9b/32.png) [@JPdworkin](https://boards.straightdope.com/u/JPdworkin)\ **Post date:** [September 3, 2003, 2:58pm UTC](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519/28 "2003-09-03T14:58:59Z")
There was a fairly famous case of a B-52 pilot who wanted to try and roll one. There were some famous pictures of it in a (0 degree bank in Time a few years ago that I can’t locate, but here’s an intersting case study on the whole thing by an Air Force pilot: [http://www.crm-devel.org/resources/paper/darkblue/darkblue.htm](http://www.crm-devel.org/resources/paper/darkblue/darkblue.htm) Larger aircraft tend to have flexible wings. I crewed on EC-121s (Lockheed Constellation airframe) and remember watching the wingtips bounce up and down in any kind of turbulence. The big boys are not designed for that kind of manuever and if you read the report that someone posted on the China Airlines incident, you’ll see that their roll was nearly vertical and damaged the aircraft significantly. Even with all the thrust they might need to maintain altitude, I doubt the airframe could take the rotational stress. ---
**Author:** ![JPdworkin](https://avatars.discourse-cdn.com/v4/letter/j/b19c9b/32.png) [@JPdworkin](https://boards.straightdope.com/u/JPdworkin)\ **Post date:** [September 3, 2003, 2:58pm UTC](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519/29 "2003-09-03T14:58:59Z")
There was a fairly famous case of a B-52 pilot who wanted to try and roll one. There were some famous pictures of it in a (0 degree bank in Time a few years ago that I can’t locate, but here’s an intersting case study on the whole thing by an Air Force pilot: [http://www.crm-devel.org/resources/paper/darkblue/darkblue.htm](http://www.crm-devel.org/resources/paper/darkblue/darkblue.htm) Larger aircraft tend to have flexible wings. I crewed on EC-121s (Lockheed Constellation airfame) and remember watching the wingtips bounce up and down in any kind of turbulence. The big boys are not designed for that kind of manuever and if you read the report that someone posted on the China Airlines incident, you’ll see that their roll was nearly vertical and damaged the aircraft significantly. Even with all the thrust they might need to maintain altitude, I doubt the airframe could take the rotational stress. ---
**Author:** ![FordPrefect](https://avatars.discourse-cdn.com/v4/letter/f/e99b99/32.png) [@FordPrefect](https://boards.straightdope.com/u/FordPrefect)\ **Post date:** [September 3, 2003, 3:38pm UTC](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519/30 "2003-09-03T15:38:09Z")
Many of the non-aerobatic Cessnas (the only ones I am partly familiar with) have gravity-based oil pumps, i.e. they pump the oil to the top of the engine and let gravity take care of the rest. IIRC, there are very few helicopters capable of looping, and I think the problem has less to do with the engine than it has to do with how the rotors can swing and fold. Basically, if a helicopter is inverted, gravity is pulling the airframe through the rotor assembly and they are not built, typically, to withstand that and the airframe will crash through the rotors. ---
**Author:** ![JPdworkin](https://avatars.discourse-cdn.com/v4/letter/j/b19c9b/32.png) [@JPdworkin](https://boards.straightdope.com/u/JPdworkin)\ **Post date:** [September 3, 2003, 5:36pm UTC](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519/31 "2003-09-03T17:36:49Z")
There’s a video of the B-52 crash I mentioned in an earlier post available here: [http://www.globemaster.de/airextreme/jets.html](http://www.globemaster.de/airextreme/jets.html) ---
**Author:** ![trebor](https://avatars.discourse-cdn.com/v4/letter/t/85f322/32.png) [@trebor](https://boards.straightdope.com/u/trebor)\ **Post date:** [September 4, 2003, 3:36pm UTC](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519/32 "2003-09-04T15:36:00Z")
> [@](#): > > \*Originally posted by j\_sum1 \* > \*\*Shortly after 9/11 I was talking with a commercial pilot. I asked him what he would do if he found himself in similar circumstances. Without a moment’s hesitation he replied, “flip it upside down”. \*\* Your pilot friend should think a bit more on the subject. There is no need to roll the plane. Simply put it through a series of dives and climbs, reaching extremes of -1 and +3 Gs (a more extreme version of the 0,+2G profile used in astronaut training), and you will ruin the day of anyone who isn’t strapped down. Lather, Rinse and Repeat as needed. However, a much simpler solution is a reinforced cockpit door, some cameras so the pilots can see what is going on in the cabin, and long prison terms for any pilot who opens that door for any reason during a crisis, even if the bad guys are killing and eating babies on the other side. There is no reason why a 747 cannot do a Barrel Roll; think of it as a corkscrew spiral. The determining factor will be whether the plane has enough roll authority to get “over the top” before it bleeds off too much airspeed and stalls (assuming it doesn’t have enough engine power to prevent this from happening), and similarly enough roll authority to get it “under the bottom” before the plane speeds up past its operating limits. Similarly, for a loop, the plane would go into a dive until it was going near VNE (Velocity, Never Exceed), pull up, and you would need enough pitch authority to be able to get over the top before you stalled out, and then get under the bottom before you passed VNE again. Whether a 747 has enough pitch authority to loop is an open question; it certainly has enough roll authority to do a barrel roll. ---
**Author:** ![QuasiQubit](https://avatars.discourse-cdn.com/v4/letter/q/9dc877/32.png) [@QuasiQubit](https://boards.straightdope.com/u/QuasiQubit)\ **Post date:** [September 5, 2003, 2:50am UTC](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519/33 "2003-09-05T02:50:16Z")
> [@](#): > > \*Originally posted by Herb Twoleaf \* > \*\* > Has anyone ever looped or rolled a helicopter? Thought I once saw a documentary where such a stunt was performed for a movie, though maybe it was all a hoax. \*\* I have seen video of a Russian helicopter do a loop, it was during a CBC documentary. I don’t remember the title of it, but it had something to do with weapon sales. ---
**Author:** ![Wikkit](https://avatars.discourse-cdn.com/v4/letter/w/c0e974/32.png) [@Wikkit](https://boards.straightdope.com/u/Wikkit)\ **Post date:** [September 5, 2003, 3:05am UTC](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519/34 "2003-09-05T03:05:14Z")
[An article on Scienceweb](http://www.scienceweb.org/movies/bluethunder.html) says that “any helicopter can theoretically do a loop” but that it would probably be illegal due to the way aircraft are certified in the US. ---
**Author:** ![grabser](https://avatars.discourse-cdn.com/v4/letter/g/f05b48/32.png) [@grabser](https://boards.straightdope.com/u/grabser)\ **Post date:** [September 5, 2003, 4:43am UTC](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519/35 "2003-09-05T04:43:43Z")
Wise man said, “Two things keep a helicopter in the air. One is the brute power turning the rotors (\*) and second by the sheer ignorance of the pilot”. - Helicopter rotors also produce lift, some angles of attack (angle of the airfoil to the oncoming ambient air) provide optimal lift, other angles produce less lift. Either way, the helicopter will stay in the air as long as the rotors are turning, no matter what the attitude of the airframe is (altitude is another question). Although, most helicopter rotor blades are capable of producing negative lift. Meaning, an inverted helicopter could (theoretically) hover. I promise you, I will not be near the test flight! Ever heard of auto-rotation. It is a method of decoupling the helicopter main rotors from the engine which allows the airframe to drop like a rock (or a ton of rocks). Shortly before crashing, the pilot (or otherwise qualified \*ignorant person) would pull up on the collective (height adjusting control next to the pilot) adjusting the pitch of the main rotors causing a major “bite” into the air which creates maximum lift, slows the rate of decent and softens the crash. This is practiced by helicopter pilots everyday and quite successfully at that. As far as flying a turbine powered fixed-wing aircraft inverted… The turbine engine is designed, as well as all components (fuel, oil, etc.) thereof, to withstand inverted flight. The F-16’s systems are not much different than that of the commercial airliners, just more expensive. A Cessna 152 or Piper Cub are both capable of inverted flight. But it is highly likely to experience some sort of engine damage due to lack of lubrication, possibly loose it’s fuel supply and airframe damage is another likely result. This due to the gravity fed systems aboard. Back to the original subject at hand: All in all, any aircraft can, theoretically, do a barrel roll or loop. It is the act of Mother Nature that will cause such test flights to go “belly up”. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [September 5, 2003, 3:05pm UTC](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519/36 "2003-09-05T15:05:48Z")
> [@](#): > > \*Originally posted by Ian Orchard \* > \*\*It would be interesting to have a crack at a loop in a simulator. \*\* I’m curious about this. Cecil wrote his article in 1978 and I assume simulator technology was considerably worse, if not altogether non-existant, in 1978 than it is today. I would think someone by now, if only to just goof-off, has taken a 747 for a loop in a simulator (unless airlines take a dim view of such a thing to the extent that they don’t want anyone to even be thinking of such a thing…even in a simulator). I guess my real question is if simulators are sufficiently advanced to account for all sorts of things such as airframe integrity, fuel delivery and so on that a simulator would be a good indication of whether such a thing can be done. I know that it will never be a 100% thing compared to doing it in the real world but is it close enough? ---
**Author:** ![MonkeyMensch](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@MonkeyMensch](https://boards.straightdope.com/u/MonkeyMensch)\ **Post date:** [September 6, 2003, 2:25am UTC](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519/37 "2003-09-06T02:25:13Z")
There’s an interesting article in the May 2003 issue of _Air and Space_. B-47s routinely flew split esses and half Cuban eights during an experiment with lob bombing approaches. [qoute]…the real fun part fo the missions was doing aileron rolls on the way to the bombing range. [/quote] Yikes. ---
**Author:** ![Kilt-wearin\_man](https://avatars.discourse-cdn.com/v4/letter/k/82dd89/32.png) [@Kilt-wearin\_man](https://boards.straightdope.com/u/Kilt-wearin_man)\ **Post date:** [September 15, 2003, 9:27pm UTC](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519/38 "2003-09-15T21:27:52Z")
Several modern helicopter designs will roll and loop. The R/AH-66 is one I’ve seen video of performing rolls, and I’ve seen video of the AH-64D Longbow Apache and the AH-1W SuperCobra in loops. I love the Discovery Wings Channel. [Previous page](https://boards.straightdope.com/t/aerobatic-747s-and-dc-10s/198519.md?page=1)