Cecil, you are a God, but in this case you are in error. It’s called a barrel roll because the plane flies a spiral inside a huge imaginary barrel. There is no more stress on the plane than there is during normal flight maneuvers.
This clip is a statement by the man who rolled the 707, and as you can see, his superiors were not all that unhappy about it.
You’ll notice that he says that it’s a one-g maneuver - someone sitting in the cabin would not feel a thing if it were done properly.
Here is a clip of Bob Hoover - also a God - rolling an executive transport (I believe an Aero Commander Shrike Commander) while pouring tea, and with the plane full of generals. Please read the entire wiki entry, and you will feel the same as I do about this great man.
Now loops! That’s a different story. But it’s not impossible.
You’d want to start very high because with such an airplane, not designed for aerobatics, you would want to stay under 4 g’s, and you’d lose a lot of altitude gently bringing it out of the dive. It’s entirely possible to keep positive g all the way through the loop, and you would make a very distorted loop, but Bob Hoover could do it!
Joe Hilbig
ps: I love your work. And I love that little cat of yours.
There’s no question that a barrel roll can be accomplished with very minimal stress on the airframe, or that someone can pour and drink a glass of wine throughout the maneuver. But it can’t be done without exceeding 1G.
Whether a person on board could feel it is a question of how sensitive that person is. An inertial measurement unit could of course tell you exactly what maneuver the plane performed.
Indeed YOU are incorrect. From the start the plane is flying along at 1G. From there you apply both elevator and ailerons. The moment you apply elevator, you exceed 1G. Furthermore, the plane is moving vertically downward prior to exit. Returning to 1G level flight REQUIRES more than 1G.
If you don’t believe me, please provide the flight profile (x, y, z, t) that the plane can follow through a barrel roll without exceeding 1G.
http://www.youtube.com/watch?v=KYQS3qAIjAo shows a Concorde pilot speaking about a barrel roll. Barrel roll - Wikipedia mentions the Concorde’s barrel rolls.
I seem to remember a friend, who was there and witnessed the crash, saying that the Tupolov 144 tried to do a rocking manoeuvre at the Paris Airshow in the June 1973 and fell to bits; information on Internet gives other reasons for the accident.
My copy of the 1975 Cessna 150 Aerobat flight manual is rather specific that you do not increase elevator until mid-way through the maneuver. Also, as entry into said maneuver in the C150 Aerobat is at the end of a shallow dive it is entirely possible to be at less than positive one g at the very start.
I would have much more confidence in your answer if it had as much information as a rather basic flight manual for a minimally powered aerobatic aircraft. As I am not, myself, an aerobatic pilot I’m won’t presume to engage in more detail than that.
Incorrect. If you are at negative g’s elevator application may or may not result in even positive g’s, much less any sort of guarantee you’d exceed 1 g.
Also, I’m rather surprised you aren’t arguing that an application of aileron will also result in an increase in g forces, which it certainly can. I am concluding that you are either not a pilot yourself, or one with a very poor understanding of how an airplane works.
Your first, fundamental error here is in the assumption that the maneuver MUST start with the plane under 1 g of force. It doesn’t have to, even if that is a common state upon entry. It’s rather like stating that stalls only occur at low airspeed - that is untrue. They most commonly occur at low airspeeds, particularly in training, but can certainly occur at ANY airspeed given the proper conditions.
I’ll take the word of numerous aerobatic pilots of my acquaintance over the random musings of someone unknown to me on the internet who will not even state his/her credentials in this matter, and who has so far demonstrated a poor understanding of how airplanes work. Now, if it’s just a matter of dashing off an answer in 25 words or less and oversimplifying matters that’s an understandable error, but around here the usual method is to dash out the short answer and then either (say it’s actually complicated in parenthesis) or add an additional paragraph with the complete explanation for those interested. Mathematical equations are also permitted, if you can get them to post in a readable manner.
Now, maybe you have a PhD in aerodynamics or something, but if you do you sure posted a sloppy answer.
As I AM an aerobatic pilot, and an aero engineer with both a B.S. in Aero and an M.S. in aero with specialty in dynamics and control, perhaps you should have more confidence in my answer than in a basic flight manual. What’s taught in groundschool and basic flight manuals is often nonsense.
Your statement makes no sense. What is “negative g’s elevator”?
I’ve been a pilot for over 30 years. I’ve flown aerobatic, sailplanes, helis, hang gliders, paragliders, ultralights, and helis. I understand how an airplane works FAR better than you ever will.
YOUR most fundamental error here is arguing about something you don’t have the first clue about.
Let’s boil this down to basics… if the plane is descending at ANY time during the maneuver, and ends up back in straight and level flight, it WILL experience greater than 1G in order to get it back to straight and level flight - no two ways about it. This is true of any vehicle - winged or not.
As you wish. I certainly had not been asked to state my credentials. Now I have.
Do the rules of this forum permit me to call you an idiot or an asshole?
I’m sorry if correct strikes you as sloppy (asshole).
I never stipulated the dive to be “constant”, now did I? You can’t stop with the assumptions, can you?
And we are supposed to know that… how? Seriously, if you don’t tell people what you’re credentials are, particularly when you’re new around here, we aren’t going to know. None of us are mind readers. Maybe you should have started with “Based on my credentials X, Y, and Z I say…”
Yes, which is precisely why I won’t just take the word of someone I don’t know. Thus, when you showed up contradicting what I’ve been told by sources I actually do know I didn’t just take your word on anything, I want you to back it up. You are correct in that my sources MIGHT be wrong… but an “I said so” doesn’t constitute proof.
Frankly, I’m hoping one of the other pilots who has been around her for awhile will weigh in on the question, as I wouldn’t mind a more in-depth look at the matter now that someone who claims to be an aviation expert has said that what I’ve been told for decades is, in fact, untrue but around here we require proof and cites.
You don’t know what a negative g force is? And you claim to have degrees in aviation? “When under negative g’s” followed by “elevator application” or if you prefer “application of elevator” - you really couldn’t parse that sentence?
Seeing as you don’t know who I am that’s a pretty bold statement - I mean, you have no clue if I am someone knowledgeable or an internet poseur, do you? Assumptions, again. They’ll get you in trouble one day.
And while you may be some sort of skygod, you sure don’t do so well in posting. While good written communication skills aren’t essential to being a pilot it sure can’t hurt you to acquire them.
My understanding is that a barrel roll is helical roll around the direction of flight - but the direction of flight does not have to be straight and level, now does it?
Of course if you’re working from a different definition that might be half the problem, but if so, let’s clarify what, exactly IS the definition of barrel roll so we can be sure we’re arguing about the same thing.
No.
You might do better if you read the rules of the board prior to posting, where it is very clearly stated what sort of language is and isn’t allowed, and where.
Then you have no excuse. Tell me, do you regard the flight regulations in such a cavalier manner while airborne?
Sorry broomstick, but you’re simply full of it. You’re making silly and incorrect statements. I’m not going to let you try and redefine the problem, or claim I “refused” to give my credentials. My communication is fine. The way I know that I’m far more knowledgable about how aircraft work is simple… I don’t have to know you, I just have to see what you post here.
I think we can agree that during a barrel roll the plane is descending at some point in time, and that it ends up straight and level in the end. If these two things are true the plane and pilot will feel more than 1G - period. No need for further details, and no need for more misdirection and insults from you.
ETA: I’m not the one posting incorrect opinions and hearsay as fact. Calm down and check your facts. The paragraph above is ALL that’s needed. You don’t need aerobatic comp pilots, flight manuals, or B.S. to figure this out. You WILL experience more than 1G in a barrel roll - every F’ing time - I don’t care who performs it.
To this reader, who knows some physics, but not aerobatics, this entire thread is only smoke blowing from both sides there’s a decent definition in place of what a “1g maneuver” is. Along what line (or lines) are we measuring, and does gravity count?
I never said you refused to give your credentials - which would be silly because you obviously have, I merely suggested that you give them FIRST next time.
Again, around here “I said so” is not considered a valid proof. You seem to want people here to simply take your word on whatever pronouncement you produce.
Excuse me? I’m not the one who is doing the insulting here - you were the one who called me an @$$hole, not vice versa.
While I have enough aviation knowledge to follow your line of reasoning, for the average layperson your obvious contradictions (insisting someone else was being insulting when you were the one getting a mod warning) may make them less inclined to believe you. Thus, rather than getting into a he-said she-said argument I expressed a desire for one of the other knowledge pilots to come in here and discuss the matter as an impartial third party.
As an example, I didn’t just say “take my word for it” but quoted a flight manual in my possession. True, that flight manual might be in error, but your statement “What’s taught in groundschool and basic flight manuals is often nonsense.” does not constitute proof that that particular manual is in error. Perhaps you have a job were people who encounter you in real life can instantly ascertain your qualifications based solely on your august presence but right now you’re on a message board and have to provide what we call a “cite”.
So, rather than drag this out further I will cease to reply to you and await the arrival of one of the other highly knowledgeable aviation people who are on the Dope to determine which of your statements are accurate (which may even be all of them) and which are not. If you find that insulting, I’m sorry, but you very much got off on the wrong foot as far as I’m concerned and no, I’m not inclined to trust your word without verification.
Earth’s gravity has a force of 1 g at the planet’s surface (which is actually an average, as at certain locations on the planet’s surface you actually experience a value slightly higher or lower than 1 g, but it’s such a small difference as to usually be of no consequence).
Here is a Wiki discussing “g force”, which is a measure of acceleration. Here is another Wiki discussing “load factor”, which is often measured in “g”, as pertains to aerodynamics. This should be an adequate introduction to the topic for those unclear on the terms and forces involved, but since that are wikis there may be some details the experts will quibble about at length.
You do that. That would be best since you’re obviously not able to follow the simple logic that a plane MUST exceed 1G to go from a descending state to a straight and level one.
No you’re not. You’ve done your very best to insult me repeatedly. You claim my “saying so” doesn’t constitue proof. I never claimed to give proof. I was simply giving an answer. A correct answer - along with enough information for anyone to see why it’s correct (well - anyone with a passing familiarity with physics).
Yes, I know I got off on the wrong foot by not taking your repeated insults more gracefully. Let’s keep it simple - you were wrong, and I told you so.
“I’ll take the word of numerous aerobatic pilots of my acquaintance over the random musings of someone unknown to me on the internet who will not even state his/her credentials in this matter”
Did you mean “HAS NOT GIVEN”?
I was never asked. Please try and be wrong like a man.
Interests: Airplanes and argumen- er, discussions.
Interesting and telling. Your interests are clearly to be argumentative about something you know nothing about.
Hey, let’s look back at your first post on this topic:
So, where is YOUR proof? Where are YOUR credentials? You simply called me incorrect, and then attempted to correct me by being 100% WRONG. You’re pretty upset about having to take my statements at face value, but I’m supposed to take yours? The difference is that my credentials are genuine, while yours are hearsay from friends (who aren’t here, may or may not know what they’re talking about, and may very well not be represented well by your posts).
This is for Comments on Cecil’s Columns, not arguing over who is right. It’s gone far beyond what this forum is intended for. Take it to Great Debates if you must.