Didn't know the Skymaster was certified for aerobatics...

[DanWEC]

Agreed. Actual legality aside, (I don't think there's a debate there.) A 1g barrel roll is doable (Not that aileron roll in the video!!) and well within the operating envelope of the airplane, so purely as a thought experiment- if it doesn't exceed the aforementioned design parameters, isn't the bank angle a bit arbitrary as a legal limitation?

-Edit, the way the AFM reads, it is "turns in which the angle of bank is not more than 60*." This implied a bit more relationship with wing loading. So partially answering my own musings....

[trampbike]

A 1g barrel roll is doable (Not that aileron roll in the video!!)

You can't do a barrel roll at 1G.

[DanWEC]

Why not? Heck didn't Tex Johnson do it in a 707? I'm not an aero pilot, am I naming the wrong type of roll?

[PilotDAR]

if you can keep the loading within spec between 3.8 and -1.52 as per the AFM

How does the pilot of your average airplane measure this?

Many posters here already know this well, but it's probably time to refresh the theme...

An element of the certification of an aircraft is operational limitations and approved maneuvers. It is required that they be stated on the limitations placard. Flying the maneuver is one thing, but the tolerance for excursion is another. Sure, you can roll many planes ( I found myself in a roll during flight testing of a Lake Amphibian - beautiful!), but does the aircraft have the capability to let you safely out of a botched maneuver? How would you know until you find yourself there?

All single engined certified planes must demonstrate spin recovery during certification testing, so why are not many spin approved? Because the margin for recovery from excursion or imperfect technique is inadequate. A well executed spin recovery in a forward C of G Caravan will require a 2.5G recovery near Vne to get out. Not much room to get it wrong, and really difficult to execute correctly without a G meter!

So the intrepid 337 pilot knows what many of us know, it'll roll okay. But if the roll were to be botched, is there room to get out without bending or stretching something important? Would he know if he did? Would he report it if he knew?

[cgzro]

Why not?

The pitch up at the beginning means more than 1G, probably 1.5 to 2G's. Then the pitch up again at the end also requires more than 1G. The only way to roll it within the [1G , -1G] envelope is if the plane has sufficient thrust / speed and side area to maintain altitude in knife edge flight with healthy application or rudder as you go around.

The main danger in any rolling maneuver is insufficient roll rate, or relaxing or pausing the roll after the plane goes past 90 degrees. Most pilots the first time they roll will naturally make several mistakes. The first is not tightening the seat belts enough so their ass lifts off the seat as you go negative. Then when their ass goes off the seat they naturally pull on the control column which pulls you toward the ground causing increased altitude loss and greater speed/G required for recovery. The third error is not maintaining sufficient aileron which slows the roll and means longer time without the wings lifting the way you want and increased recovery speed and altitude. If you are unlucky you can end up with the nose very low during the pull up and a very high speed and over G during the recovery. These are all mistakes that are best made in a plane that can take the abuse when you muck it up. Of course there is no physical reason why most planes could not execute rolls with little risk but in a fragile airplane it requires a lot of skill to do it perfectly every time... remember 1 in 100 botch ups are pretty poor odds.

Also the pre-flight for an aerobatic flight includes a few more items such as loose items checks etc. which likely have never been done in a non aerobatic plane and you risk getting hit in the head by something. I once got a mag-light right in the temple during a low roll and fire extinguishers have been known to come loose.. not fun so careful pre-flight is pretty important. We typically also usually have redundant seat belts because well ... its not pretty when you come loose.

[oldtimer]

What happens to the attitude indicator in a roll?
Would you want to enter IMC after some yoyo has been rolling the airplane?
If he has done it once, how many other times has he done this.
If I were in a management position (which I am not) I would have fired his sorry ass out the door immediatly.

[CpnCrunch]

Also the pre-flight for an aerobatic flight includes a few more items such as loose items checks etc. which likely have never been done in a non aerobatic plane and you risk getting hit in the head by something. I once got a mag-light right in the temple during a low roll and fire extinguishers have been known to come loose.. not fun so careful pre-flight is pretty important. We typically also usually have redundant seat belts because well ... its not pretty when you come loose.

In the video it looks like there's a cellphone and a metal can flying around the cockpit.

[co-joe]

What happens to the attitude indicator in a roll?
....

Pretty sure that for every roll to the left you do, you have to do one to the right to undo it.

[trampbike]

Why not? Heck didn't Tex Johnson do it in a 707? I'm not an aero pilot, am I naming the wrong type of roll?

As cgzro said, even for an aileron roll you'd need more than 1G to initiate the maneuver and to recover.

Tex Johnson did an aileron roll, which is also what that Skymaster driver did.
An aileron roll is a rotation around the longitudinal axis of the aircraft. Some pitch-up will be required initially for slow rolling machines, otherwise the resulting nose-low attitude after the completion of the roll could be a problem. In a fast rolling aircraft, you can pretty much just use ailerons to complete the roll.

A barrel roll requires a G-loading that is higher than 1G throughout the maneuver (or less than -1 if you want to do it inverted...). The flight path is shaped like a corkscrew. Think of it as the blending of an aileron roll with a loop. You're pulling on the stick while also rolling the aircraft.

Hope this helps.

[rigpiggy]

There was a paraplegic aerobatic performer used these in the 90s. Steve soper if i recall

[cgzro]

[quote]What happens to the attitude indicator in a roll? /quote]

If its mechanical/gyroscope based I guess its a bit hard on it. The Extras that have gyro packages come with quick disconnects so you can slide out the gyro instruments prior to aerobatic flight but modern stuff uses solid state gyros which I doubt are harmed by rolling.

[goingnowherefast]

Go to the 2:00 mark.
https://www.youtube.com/watch?v=jLFwJlPVYyY

Pretty sure these guys aren't Bob Hoover.

Also, from CAR 101.01
"aerobatic manoeuvre means a manoeuvre where a change in the attitude of an aircraft results in a bank angle greater than 60 degrees, an abnormal attitude or an abnormal acceleration not incidental to normal flying"

You aren't going to break the airplane doing a proper roll, but it's still illegal.

[digits_]

Go to the 2:00 mark.
https://www.youtube.com/watch?v=jLFwJlPVYyY

Pretty sure these guys aren't Bob Hoover.

Also, from CAR 101.01
"aerobatic manoeuvre means a manoeuvre where a change in the attitude of an aircraft results in a bank angle greater than 60 degrees, an abnormal attitude or an abnormal acceleration not incidental to normal flying"

You aren't going to break the airplane doing a proper roll, but it's still illegal.

So if we all start doing loops -and thus redefine 'normal flying'- we will all be legal !

[redlaser]

It boils down to this, aerobatic type aircraft are built to whitstand higher wing loads, whereas Normal or utility aircraft do not, I have see Cessna aircraft come back with bent ailrons after a student pilot or pilot have pushed the structure beyond its limits in doing aerobatic manoeuvres, So before doing a snap.barrel, or ailron roll check your POH to see if any of these manoeuvres are authorised, Normal cat. Aircraft are not.

[DanWEC]

Thanks for the info on the rolls. I was fairly sure I knew the difference between an aileron and barrel roll, but when you hear someone refer to a 1g barrel roll is that just an incorrect term, or loose approximation as opposed to blowing the shit out if it?

So next, is it not feasible for an average pilot to do a roll and stay well within the structural envelope? (Ignoring the contingency g for recovery from a botched maneuver, that's good info btw.)

[trampbike]

Thanks for the info on the rolls. I was fairly sure I knew the difference between an aileron and barrel roll, but when you hear someone refer to a 1g barrel roll is that just an incorrect term, or loose approximation as opposed to blowing the shit out if it?

Those "1G barrel rolls" are more like "lazy aileron rolls", IMO.

So next, is it not feasible for an average pilot to do a roll and stay well within the structural envelope? (Ignoring the contingency g for recovery from a botched maneuver, that's good info btw.)

It sure is. You're operating out of your aircraft CoA, but it can easily be done (it doesn't mean it should, though!)

Cheers,
Oli

[PilotDAR]

So next, is it not feasible for an average pilot to do a roll and stay well within the structural envelope?

If the pilot has been properly trained, yes.

But, an error in a roll becomes very unsafe quickly. If the axis of the roll becomes downward through pilot inattention, incompetence, or fear, the pilot may well find them self descending inverted toward earth, with speed and G building up quickly. Once in this situation, it's going to end badly. I well flown roll is within the structural limits of a normal category light aircraft. However, a botched roll will exceed these limits. A botched roll probably is within the limits of an aerobatic certified aircraft.

Like many things in piloting, the maneuver itself is basically simple, but the numerous things that can go wrong create the risk, and need for competent training.

[cgzro]

So next, is it not feasible for an average pilot to do a roll and stay well within the structural envelope?

In a slow rolling plane odds of success would be poor.
Faster rolling much easier better odds.

[JasonE]

So next, is it not feasible for an average pilot to do a roll and stay well within the structural envelope?

In a slow rolling plane odds of success would be poor.
Faster rolling much easier better odds.

Want to come teach me to roll my Cherokee?? (just kidding, I'm saving for a 2nd acrobatic plane...)

[CLguy]

First a 337 cannot be considered as a slow rolling airplane. An aileron roll done properly will put less stress on the airframe than most steep turns and there will be no negative G's or shit floating around the cockpit. I'm willing to bet that there is more stress put on those airframes on a daily basis by those newbies trying to land them in a crosswind. You get too see some crazy shit at times!