Executing a 1G barrel roll?

[ragingbonesaw]

So what is the procedure exactly? From what I gather one pitches about 20 degrees and descends at a certain rate, but I suspect that's wrong.

[galaxy flyer]

IIRC, in the T-38, one picked a point in the nose, turned off 45 degrees and began a 2G climb and roll that held the point in on place off the nose. Not 1G, but probably not possible in a -38. One wound up 45 degrees nose high and low.

GF

[bearfoil]

I think a barrel roll must be 1G or it is not one. Tex did a pretty good one in the 'X' 707. (:D)

My friend Keith says a BR in the Talon is frustrating, it wants so much to snap instead, and that is way more fun. BR, finesse. SR, cookie crumbler. especially at 720 dps.

bear

[Machinbird]

Bear, Tex Johnson did more of an aileron roll than a barrel roll.
YouTube - Boeing 707 roll by Test Pilot Tex Johnson (http://www.youtube.com/watch?v=Ra_khhzuFlE)
If you will observe, the aircraft in the video is on more of a ballistic trajectory during the maneuver.
From memory, the type of barrel roll you do depends a lot on airspeed. We used to do 90 off heading barrel rolls in the T-34 and other slow aircraft and 60 or 45 degree off heading barrel rolls in various tactical jets. By off heading, I mean how far you were off initial heading as the nose fell through the horizon inverted. Roll rate and g are not constant although g is always positive if done properly. Not a terribly difficult maneuver.

[Jane-DoH]

bearfoil,

My friend Keith says a BR in the Talon is frustrating, it wants so much to snap instead, and that is way more fun. BR, finesse. SR, cookie crumbler. especially at 720 dps.

What do you mean by cookie-crumbler?

[Capn Bloggs]

To my way of thinking, you cannot do a barrel roll at 1g. Firstly, you have to pull the nose up to start it. That's more than 1g. Secondly, you have to pull more than 1g to get the nose back up to the horizon again after being inverted, unless you do a wiffodil and twinkle roll to wings-level at the end, but then you'd end up at a higher altitude than when you started.

It would be quite easy to do in a big jet at less than 2g provided you don't let the nose get too low after inverted and have to pull like a $%^&*@ to recover; start nose-high and keep the roll-rate up ie don't do it the way Tex did it. Start rolling with the nose well up.

[Dan Winterland]

Exactly. To get 1g while inverted, there's going to have to be some acceleration at the start of the manoevre if it is indeed going to be a barrel roll. If you do acheive inverted without pulling more than 1g, the nose is going to be very low and the will be some acceleration to recover.

[Jane-DoH]

galaxy flyer,

So you'd turn 45-degrees off heading, then pull up while rolling; or you while rolling you reached a maximum of 45-degrees off the original heading?

[Checkboard]

It isn't possible to do a 1 G anything in an aircraft (apart from parking it on the ramp!). When people talk about "1 G barrel rolls" they generally mean a balanced, positive G barrel roll - one in which you could place a glass of water on the glare shield, and have it stay there.

So you'd turn 45-degrees off heading, then pull up while rolling; or you while rolling you reached a maximum of 45-degrees off the original heading?
The barrel roll is a "twisted loop" in which the aircraft flies a corkscrew path through the air. If you are in flight, stooging around for your own enjoyment, you choose the axis of the manoeuvre off to one side, then (accelerate if you need to) and pull into the figure, introducing the roll after the initial pull. With this method, once you have recovered to level flight, you should be flying on the same heading - but the aircraft will be displaced to the left/right of the original track.

If you are flying the figure for a ground observer (which would be unusual), then you turn off you track in the opposite direction to the roll as you dive to accelerate - this keeps the axis of the figure aligned along your display line.

[petermcleland]

A 1G barrel roll would be impossible...at best you could expect 1G at the inverted stage and 2G at the completion of the roll but still nose down but recovering. The way I was taught was to turn off to say the right with turn overbanked to get the nose down. Then start the roll to the left but maintaining positive G by keeping back pressure on the stick. For the first half of the roll the nose would be above the horizon and for the second half it would be below the horizon. To avoid a steep nose down attitude at the end of the roll, you need to ensure that the nose comes high enough above the horizon in the first part of the roll. Mistakes are usually to not get the nose high enough before the roll passes the 90 degree of bank station. This will result in a steep nose down attitude as you come out of the roll with large loss of height...So next time get the nose higher :)

The slower you roll, the more difficult the manoeuvre, so leading a barrel roll as a formation aerobatics team leader is pretty hard to do well...If you roll too fast you will start shedding wingmen :rolleyes:

[Romeo E.T.]

during my basic aerobatics course on a De Havilland Chipmunk, I was taught to pick a prominent feature on the horizon on either wingtip, i.e. 90deg of current heading, then lower the nose into a shollow dive to gain speed (possibly around 120mph), and then simulataneously pitch up and roll steadily until the "feature" previously selected appears directly on the nose as the aircraft passes thru inverted straight and level position, now without any extra rolling or pitching forces it was just a matter of allowing the manouvre to "complete itself".

[NigelOnDraft]

Not a terribly difficult maneuverMmmm... I remember some poor soul trying to teach me, and I now try to teach others. It is a very simple manoeuvre once you understand what you are trying to achieve. To get to that stage, safely, is far from easy, since you are having to co-ordinate 2 "rates" (roll and pitch). From the number of fatalities, frights and VNE exceedences I would therefore disagree with your statement :=

A 1G barrel roll would be impossible...Agreed in the classic sense. Reviewing that video, firstly TJ never describes it as a Barrel Roll, and nor would I ;) It is potentially all flown at 1g - he's started rolling, and kept the 1g applied - end result is in the inverted position the nose is well below the horizon and rapidly falling further... so could well have all been done at 1g, but he would have needed somewhat more to arrest the rate of descent :D

Anyone trying to do Barrel Rolls, please do NB the 1 absolute safety gate - as the nose passes down through the horizon (pitch) the wings must be at or past the inverted position (roll)... if not then check forward, roll upright and try again this time with a higher roll rate / lower pitch rate - do not "pull thru'" :{

In teaching, I tend to get the student to pitch (only) until their feet are on the horizon, and only now slowly start the roll, while still keeping the pitch going. The common errors are to start rolling too soon / too quickly, and stop pitching up. Only when they have got a grasp of the relationship between roll and pitch do I add ground features / angles off etc.

NoD

[Lightning Mate]

A 1g barrel roll is impossible.

LM. (one time international aerobatic competition winner) ;)

[BOAC]

OK Bloggs - now let's try a loop to the left:D

[henry crun]

Maybe I have misunderstood some of the descriptions here, but it appears to me there is some variation in what exactly a barrel roll is.

This is how it was described to me by my RAF instructor, admittedly a long time ago, so it might have changed
Commence at A with wings level on the horizon, pulling up and rolling right to have 90 degrees of bank at B, inverted as we pass through the horizon at C, 90 degrees of bank at D, and recover back at A.

http://img.photobucket.com/albums/v712/crun9/broll.jpg

[Air Tourer]

I've seen some awful diagrams of the aircrafts supposed position during barrel rolls. Henry's isn't so bad but I don't think many underpowered trainers could start from "A" without falling out at the top.

I did a few in a Victa, completing the barrel shape regardless of where the a/c was this way or the other. Started with the nose on a feature, dived and turned to arrive at Henry's "A" with a bit of speed up, probably already at 90deg by C, falling to D at upright and pulling back to A to finish. Rough and self taught, but my instructor wouldn't sign my log book for barrel rolls because, "you can do them better than me." Mind you, he signed for everything else. :rolleyes:

[fivegreenlight]

Worth watching this

YouTube - Stopped engine aerobatics (http://www.youtube.com/watch?v=9ZBcapxGHjE)


about 2 mins in is a good demo. I imagine >1g ...

I love the sound effect of the tea being poured !!

[Lightning Mate]

BOAC,

OK Bloggs - now let's try a loop to the left:D

Would that be with one or nine mate. :E

[BOAC]

The only 'bent' nine-ship one I can recall was DD's arrival at Barton along the wrong canal, but by skilfully bending the loop he arrived on datum at the bottom without shedding one of the boys.:)

[Lightning Mate]

That's called skill mate. :)

[Lightning Mate]

One understands that the secret of a well executed barrel roll is to ensure that one gets the nose high enough to start with and have due consideration for ones' wingmen:

http://i636.photobucket.com/albums/uu82/Lightning_29/T4s226OCUB620.jpg

[sycamore]

At this point a simple training aid may help;; use the centre cardboard tube from a bog-roll,or kitchen roll; highlight the `skewed join line` along the tube; from one end draw a little aircraft symbol in the `direction highlighted`.
Draw further symbols at each 90 deg position around the tube,and along it`s length....You should now have a `corkscrew` flightpath,for either a LH/RH barrel roll.
Henry Crun`s diagram is probably taken from AP129,and is incorrect,in that the symbols of the aircraft are 90 deg. out.
At position `D`(6 o`clock) the aircraft is at the lowest point in the roll,with wings level; at `A` the aircraft is at the wings vertical position and climbing at about 45-60 deg nose-up; at the position `B`the aircraft is wings level,inverted, nose above the horizon,just maintaining `positive G`,but still rolling,and then position `C` is 90deg wings vertical,and so on...
The critical point is at the top of the barrel,as noted by NoD,that the wings should be level,and the nose above the horizon; if not, you can end up in serious `crap`....
Now you can look at your `Blue Peter` aid and see where the heading and pitch attitude should be at any point around the barrel.
For an `outside view`,go to YU-TUBE,and search `tonneau barrique d`un Transall`.Another couple of videos,search for `piloted by Sobolev`....
I should add that depending on your aircraft type ,one can get away with about 2G pull at the start,and `float` over the top....(with practice !)
If you want to see `how not to do it, then search for `Biggin Hill Invader crash`...

[Checkboard]

-b7kSSAIIpI

PuedcOSOh0o

[Agaricus bisporus]

Surely Henry's picture should show the horizontal axis of the roll set at some 10 - 15deg above the horizon so as to cope with the inevitable fall through that would otherwise require the recovery action so clearly pointed out by NigelOnDraft.

The way I was taught in the Bulldog was to be aligned on your chosen line-feature, drop the nose and bank 45' away from the direction of intended roll, then reverse the direction of roll into the maneuvre and commence the pull, thus establishing on the profile at the half past four or half past seven point,nose lowand rising with 45 deg bank and ensuring that wings level occurred at least 10deg above the horizon. That in turn should ensure wings level inverted on the other side and still with nose appreciably above the horizon - or else chuck it away as NOD describes. The BIG briefing point was nose 10' above the horizon at wings level pitching up to ensure a safe pitch attitude when inverted.
It might be different in a fast jet, but that works in a light single, or at least, as I recall it.

[John Farley]

IMO Henry's diagram is perfect - so far as it goes What he misses is that you pass through A in a recovery from a preceding dive. Yes you are wings level at this point but you do need about 2 g at the same time. As BOAC says you are doing a (low g) twisted loop. Indeed it is the twisted bit that allows you to loop at such a low g without running out of airspeed.

Re accidents during barrel rolls at airshows when I was a CAA display authorisation examiner I used to fail anybody doing a barrel roll along the display line unless they started it rolling TOWARDS the crowd. This is because the roll only goes wrong in the second half and if you start it towards the crowd then during the nasty second half you will be pulling and travelling away from the crowd as you woosh into the deck.

[sycamore]

A-B, correct; if you take your `B-P` kitchen roll,and set the `start at about4/8 o`clock,to build speed in a dive,and look `thru` the tube , the centre axis should be ` always above,seldom level,never below ` the horizon.. if the axis is below,the aircraft will have the nose below,and that is `chicken -time`,ie push ,roll upright`,and take a deep breath..
There is another video taken from inside the Transall,somewhere on Y-T, but they don`t show the wine pouring..!

[Pugilistic Animus]

Executing a 1G barrel roll?


By finding a safe, experienced and competent aerobatic instructor...:=

[Lightning Mate]

This is because the roll only goes wrong in the second half

Too damn right John.

All vertical or semi-vertical manouevres occur in the initial pull-up. The second part which kills people is merely a consequence.

Sorry, but too many ignorant :mad::mad: amateurs around .......

[VH-Cheer Up]

Quote:
This is because the roll only goes wrong in the second half
Too damn right John.

All vertical or semi-vertical manouevres occur in the initial pull-up. The second part which kills people is merely a consequence.


Isn't this like saying the crash only happens at the end? When the pilot stops flying in the middle of the air and goes to close to the edge?

Most accidents I have read about seem to occur at the edge of the air, where the sky runs out and the terrain begins.

Aerobatics aficionados might enjoy this video of Bob Hoover (http://www.alexisparkinn.com/photogallery/Videos/2006-3-11_bob_hoover.avi) with some interesting dead stick manoevres and where he pours a glass of iced tea while executing a barrel roll.

[Jane-DoH]

henry crun,

Position's A/B/C/D mark the position of the left wingtip in a barrel-roll to the right; A/B/C/D would mark the position of the right wingtip in a barrel-roll to the left assuming the image was mirrored I guess...


John Farley,

IMO Henry's diagram is perfect - so far as it goes What he misses is that you pass through A in a recovery from a preceding dive.

You mean you're pulling out of the dive after finishing the barrel-roll?

[henry crun]

Jane: Correct.

sycamore: Not copied from AP129; dredged out of an aging and, at times, imperfect memory.

[JenCluse]

Dear Air Tourer, you (and you, too, Agaricus bisporus, just as well) describe the same technique that I laboured to develop to achieve a positive-G manoeuvre in a 100 hp Victa, that you could put your dear ol' mum through (done) with her eyes shut, but then the second time ask her to now open her eyes 'at the top.' Frabjous fun, if you have the right mum/friend/victim. Otherwise hysteria results. Pick your 'victim' carefully.

The trick is not to achieve one-G. It is really to manage energy/ flight-path to achieve 'never-negative-G'. (Simple engines keep running then.)

This whole discussion really boils down to how much energy your aeronautical device has, how much drag, how much (sic) wing loading, how much (sic) velocity, roll rate, aileron drag, etc etc.

Our discussion's we-*can-vary-the-rifle-bore military grunters can essentially point and do, as can our (magically)-excessively-powered competition aero-comp friends. Vertical hover, anyone?

We lower-order growths have to do with making the best of what we have, and what we have/had determines how you carve that bit of air, and whether you do it for your own bottom's pleasure, or for an audiences’.

Self taught (Aerobatics? Now? Dear, you've just gone solo!) much later I was having doubts about my BRs, and asked B.T. (and ancient tiggy-moth displayer of note) to help me out (my only aerobatics instruction ever: shock) and he finished up throwing his hands in the air (litterally) & giving up (on the Victa).

Yet he could carve the most exquisite aeros in a Tiger. But that was another technique altogether.

As me dear old (still firing) mum would say, "Whatever takes your fancy, said old Mother Clancy, as she kissed the cow."

Good Lord!

That's disgusting. I thought *we* invented that sort of thing. . . .



Barrel rolls, you awful minded person you. Barrel rolls.

[sycamore]

Henry et al, that is a picture that even goes back to the 1940`s,and perpetuated in AP129,but it is still wrong. The lift vector `L`,always should point to the centre axis of the `barrel`. You can do it as per the diagram,but can end up `tent-pegging`,as many have......,if at low-level.....
Actually if you look at the Transall video,the pull-up is started wings-level,and then at about 35-40 deg. N-U,aileron is fully applied,as applying full aileron at max `G` is not a good idea in such a large,long-span aircraft,but the rest looks good,also having the benefit of airbrakes reduces the speed/G/ roll in the latter part of the manoeuvre..
There is/was a heavy discussion on the `Flypast` website,of a photo supposedly showing a Dakota doing a barrel roll,but no-one actually produced the photo....Syc..

[sithfighter]

You can check my 1G roll in Youtube ;)

YouTube - RED BULL - Flying (http://www.youtube.com/watch?v=D2z_Av5P750)



D2z_Av5P750

[Agaricus bisporus]

The maneuvre pulled by the Transall is not what I'd call a BR in the classic sense, rather a low G ballistic roll of some kind. No way you could draw that around a bog-roll unless you trod on one end first. That biig pullup before the roll input and subsequent looong rolling pullout are neither symmetrical, elegant nor barrel-shaped. Looks about as natural as a cow dancing to me. Impressive, certainly. Foolhardy, probably. Barrel roll? Non.

I'm curious about the technique that commences the "BR" from level or nearly level flight. That must surely result in the roll itself being flown on an axis about 45' to the original line of flight and thus with a zig-zag ground track and the entry and exit tracks substantially offset. Goofing around apart, are aerobatic maneuvres not supposed to be flown on an axis (think display line)- hence the importance of picking a line feature and sticking to it so is this not a fudge on the lines of an axial roll being flown with the pitch up a bit - whack in lots of aileron -stop the roll when level again technique that I've seen (been subjected to) which is horribly crude.

From which, note the technique used in the axial rolls early on in the superb Russkie video esp the pitch attitude when inverted, several degrees above the horizon. Watch it again but with your eyes on his stick-hand and see the pitch inputs that go into that maneuvre too, that ain't no aileron roll which will inevitably have a slightly sinusoidal horizontal flight-path even in a FJ. I bet his was straight as a ruler. Can any FJ driver tell us if top/bottom rudder input would be used too, or was the roll-rate too fast to need it?

Sithfighter. Aerobatics in cloud? Fooling about with a can of soda while flying aeros? Holy crap, and you post that here? :ugh: Not impressed.

[sycamore]

A-B, I`ll agree the Transall BR is not a `true` or accurate figure,and if you observed along the axis it would be rather egg-shaped,as most loops are due to the speed and G being different at the bottom and top...unless you have a good power/weight ratio,and minimise speed loss.Also it depends on whether you are displaying,or doing competion,as to how the figure will look to observers.
Sobolev actually rolls inverted after t/o and then pushes up in an inverted climb.Look for the other cockpit videos,ie looking backwards...

[Neptunus Rex]

One understands that the secret of a well executed barrel roll is to ensure that one gets the nose high enough to start with...Maestro! You have it all.

[sithfighter]

One understands that the secret of a well executed barrel roll is to ensure that one gets the nose high enough to start with...

and also keep the nose straigh in the roll using rudder! some extra rudder is also helpful to increase rollrate.

[sycamore]

Sftr, a properly executed BR does Not require rudder to keep straight..it only requires rudder to keep the manoeuvre balanced...ie, keep the ball in the middle.!

[Lightning Mate]

and also keep the nose straigh in the roll using rudder! some extra rudder is also helpful to increase rollrate.
Absolute excrement of male bovine!

[Lightning Mate]

and also keep the nose straigh in the roll using rudder! some extra rudder is also helpful to increase rollrate.

A barrel roll is not a fast roll rate manoeuvre.

However, rudder is useful when executing a Derry turn, but one must be very careful at 500 feet AGL, especially when the transition from +6g to -3g must be made within half a second.

One feels that it is now time to retire from this thread.......exit with full loop away from crowdline at 90 degrees until no longer visible.

[BizJetJock]

A-B

I'm curious about the technique that commences the "BR" from level or nearly level flight. That must surely result in the roll itself being flown on an axis about 45' to the original line of flight and thus with a zig-zag ground track and the entry and exit tracks substantially offset. Goofing around apart, are aerobatic maneuvres not supposed to be flown on an axis (think display line)

The commonest use of the barrel roll in display flying is precisely to realign the axis, particularly useful when one has underestimated the on-crowd wind component. Not that any professional display flyer would ever do that....;)

[Biggles78]

And here was me thinking a Barrel Roll was something Snoopy used to escape from the Red Baron. :sad:

[sithfighter]

Another fun ride somewhere in Morocco :)

you can see at the end of the not-programmed display... the guy on ground did draw a plane with thanks written in arabic!

By the way... it's a non Aerobat Cessna!

YnsbUCDztok

[scotbill]

A classic barrel roll could be demonstrated in the B757/767 Sim but, strangely enough, was never tempted to try it in the aircraft
However, the smoothest barrel roll I ever sat in on was demonstrated by the late Neil Williams (British Aerobatic Chmpion at the time) in a Falcon fanjet. He had two passengers standing in the back drinking champagne but as it was night they never realised they had been upside down.
Wasn't close enough to see whether the direction of the bubbles was affected!

[D SQDRN 97th IOTC]

this link seems to describe a barrel roll as I understand it:
Barrel roll - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Barrel_roll)

not that wikipedia is the ultimate authority out there, but it does have the benefit of being correctable if someone believes they can describe the manoevure better.

the CAA makes the point that barrel rolls and other manoevures flown at low level can be potential killers:
http://www.caa.co.uk/docs/33/CivilAirDisplaysAGuideforPilots.pdf

not that I am an expert in these matters - and there are people posting on this thread with far more experience than Lighting Mate gives them credit for, including (ex) RAF display pilots....but the crucial part of the manoevure IMHO is to go through the gate correctly. If you don't see what you expect in terms of the numbers, your energy and attitude, then you need to start thinking safety first rather than completing the manoevure.