Inverted roll with C-172????
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Englishal,
I guess you are referring to Neil Williams, who was later to die in a CFIT accident.
Stiknruda,
Thanks for the references, have a spin or five under my belt in a variety of Zlins and Extras but never looked at the actual physics calculations, never felt anything likely to pull the tail off even after a well developed six or seven turns. Never pulled more than 3G even in a botched recovery, and i've had a few over aggressive recoveries in the early days with the 142/242. My point was to emphasise that spin forces rarely equal the forces in other aerobatic manoeuvres. Now if we want to talk about things likely to break the aeroplane, how about opening a thread on tailslides
As for your tip tanks story, I have one of my own. I once had a Zlin242 shipped to Archerfield, Brisbane and left it with the owner of a local flying school to look after. Well known aerobatic pilot and ex RAAF fighter pilot, but a bit of an arse, anyone reading this from Archerfield will know exactly who I am referring to. When I got back to Australia, he rather heatedly described the aircraft as dangerously designed as it had nearly killed him and a student with a late spin recovery and was getting quite excited until I pointed out the placard which said, no spins with fuel in the tip tanks
I guess you are referring to Neil Williams, who was later to die in a CFIT accident.
Stiknruda,
Thanks for the references, have a spin or five under my belt in a variety of Zlins and Extras but never looked at the actual physics calculations, never felt anything likely to pull the tail off even after a well developed six or seven turns. Never pulled more than 3G even in a botched recovery, and i've had a few over aggressive recoveries in the early days with the 142/242. My point was to emphasise that spin forces rarely equal the forces in other aerobatic manoeuvres. Now if we want to talk about things likely to break the aeroplane, how about opening a thread on tailslides
As for your tip tanks story, I have one of my own. I once had a Zlin242 shipped to Archerfield, Brisbane and left it with the owner of a local flying school to look after. Well known aerobatic pilot and ex RAAF fighter pilot, but a bit of an arse, anyone reading this from Archerfield will know exactly who I am referring to. When I got back to Australia, he rather heatedly described the aircraft as dangerously designed as it had nearly killed him and a student with a late spin recovery and was getting quite excited until I pointed out the placard which said, no spins with fuel in the tip tanks
Last edited by rmac; 1st Oct 2007 at 07:17.
Yes, that was Neil Williams. In fact, I recall that the wingtip left a gouge in the grass - so he judged it extremely well !!
Just read a bit of Neil Williams' book, and I noted the following point that would emphasise the nature of stress and microfails etc.
The Zlin aerobatic aircraft had an airframe life of 2200hrs when subjected to +6 and -3G aerobatics.
The same aircraft, when flown to higher unlimited aerobatic standards of +8 and -6G, was reduced to an airframe life of only 100 hrs.
Added for your interest.
The Zlin aerobatic aircraft had an airframe life of 2200hrs when subjected to +6 and -3G aerobatics.
The same aircraft, when flown to higher unlimited aerobatic standards of +8 and -6G, was reduced to an airframe life of only 100 hrs.
Added for your interest.
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in flight break ups are a low probability for accidents
) all the school staff were away at the funeral of a member who had died - he had been doing aeros in a (non aero) C150, since then I have heard of a number of instances of non aero aircraft breaking up whilst being turned intentionally upside down - I now teach aeros but I have never done it in a non aerobatic machine and never will - and when there are so many better aircraft for doing aeros in, why bother doing it in such a machine?
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Simply
....AGREE with all of you who say, 'unless your trained, in an aerobatic aircraft, in good flying practise and are showing good airmanship and preperation before the proposed aerobatic flight'...then don't do it.
I have regularly seen people in busy class g (yes i know its a free for all) who have not 'advised' anyone of their aerobatic intentions and have come very close to other aircraft out for a less exciting site seeing trip. Trained pilots or not? I have no idea.
Its just a small example that rolling and looping etc. should be part of a well thought out flight.
I have regularly seen people in busy class g (yes i know its a free for all) who have not 'advised' anyone of their aerobatic intentions and have come very close to other aircraft out for a less exciting site seeing trip. Trained pilots or not? I have no idea.
Its just a small example that rolling and looping etc. should be part of a well thought out flight.
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Soon after I passed my PPL back in the late'70s, one of the guys who'd instructed me (and had since got a job flying with Loganair) was killed, along with another club member, aerobatting a Luton Major (non aerobatic). The right wing seperated in flight.
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Quote: "But a properly executed barrel roll is a positive manouvre and the great Bob Hoover demonstrated it with a glass of water perched on the coaming all the way through".
Actually an aileron roll.
Aileron roll explained:
Barrel roll explained:
The Barrel roll is a combination between a loop and a roll. You complete one loop while completing one roll at the same time. The flight path during a barrel roll has the shape of a horizontal cork screw. Imagine a big barrel, with the airplanes wheels rolling along the inside of the barrel in a cork screw path. During a barrel roll, the pilot always experiences positive Gs. The maximum is about 2.5 to 3 G. The minimum about 0.5 G.
Not my descriptions, pulled from IAC website. http://www.iac.org/begin/figures.html#Aileron%20Rolls
Knox
Actually an aileron roll.
Aileron roll explained:
Aileron rolls are flown with the rudder and elevator in the neutral position during the roll. The aileron is fully deflected in the direction of the roll. This is the easiest of the rolls to fly.
The aileron roll is started by pulling the nose up to 20 - 30 degrees above the horizon. The elevator is then neutralized and the aileron fully deflected in the direction of the roll. The controls are maintained in that position till the roll is completed. After the roll is completed the nose is usually 20 - 30 degrees below the horizon.
Barrel roll explained:
The Barrel roll is a combination between a loop and a roll. You complete one loop while completing one roll at the same time. The flight path during a barrel roll has the shape of a horizontal cork screw. Imagine a big barrel, with the airplanes wheels rolling along the inside of the barrel in a cork screw path. During a barrel roll, the pilot always experiences positive Gs. The maximum is about 2.5 to 3 G. The minimum about 0.5 G.
Not my descriptions, pulled from IAC website. http://www.iac.org/begin/figures.html#Aileron%20Rolls
Knox
The great Bob Hoover definitely did a barrel roll with his iced tea pitcher trick. He had a glass on the panel, and poured iced tea in the glass all through the roll with one hand, while flying with the other. This requires positive G's all the way around. Or, in your description, a barrel roll.
It's at the end of this video:
http://www.youtube.com/watch?v=tOZEgKXJMCE
If I was Bob Hoover, I'd do inverted rolls in a C172. But I'm not. So I won't.
-- IFMU
It's at the end of this video:
http://www.youtube.com/watch?v=tOZEgKXJMCE
If I was Bob Hoover, I'd do inverted rolls in a C172. But I'm not. So I won't.
-- IFMU
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ok so while I would freaking LOVE to roll a 172.....NO! Its stupid. A 172 is not designed to do rolls and ****. Its a point a to point b machine. I fly one....and although it has come close to putting me in tears....I like it now. I also know...it is not made to do rolls and loops. Your kidding me!
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Quote: The great Bob Hoover definitely did a barrel roll with his iced tea pitcher trick. He had a glass on the panel, and poured iced tea in the glass all through the roll with one hand, while flying with the other. This requires positive G's all the way around. Or, in your description, a barrel roll.
Watched it again and definitely not a barrel roll.
If you watch carefully, as he enters the maneuver his ref point is the mountain range, as he comes through the inverted the same mountains are still ahead, he would have to be 90 deg to that point for it to be a barrel.
In a barrel roll you also need to apply back pressure on the yoke as you roll, (corkscrew manner), if you look carefully Bob applies no back pressure on the yoke.
An aileron roll is a positive 1G maneuver, so pouring the liquid is still possible.
Knox
Definitely wouldn't roll a C172. Craziness!!
Watched it again and definitely not a barrel roll.
If you watch carefully, as he enters the maneuver his ref point is the mountain range, as he comes through the inverted the same mountains are still ahead, he would have to be 90 deg to that point for it to be a barrel.
In a barrel roll you also need to apply back pressure on the yoke as you roll, (corkscrew manner), if you look carefully Bob applies no back pressure on the yoke.
An aileron roll is a positive 1G maneuver, so pouring the liquid is still possible.
Knox
Definitely wouldn't roll a C172. Craziness!!
Last edited by knox; 2nd Oct 2007 at 04:32. Reason: more to add
I think we have people from different continents argueing about their continent's definition of a roll.
But wherever you're from, a barrel roll isn't a 1g manoeuvre - It's a positive g manoeuvre. Even Bob Hoover couldn't fly a barrel roll at 1g -it's impossible. And an aileron roll is just that - a roll actuated by ailerons only. And in nearly all types, this will leave you nose low when completed. A slow roll is where the nose points at a spot on or above the horizon without deviating, the aircraft completes the manoeuvre without height loss. To do this, at some stage you will be flying inverted and be at -1g. This is not an elevator or rudder neutral manoeuvre - co-ordinated use of all controls is necessary to keep the aircraft level.
Some people think that barrell rolls are difficult. They are a lot easier that slow rolls. At a school I instructed at, the barrell roll was the second aeroabtic manoeuvre (after the loop) taught to the students, the slow roll coming much later. It can't have been that hard as they were usually cleared to fly them solo by 30hrs total time.
But whatever you call your rolls, anyone who aerobats a C172 is a ###t!
But wherever you're from, a barrel roll isn't a 1g manoeuvre - It's a positive g manoeuvre. Even Bob Hoover couldn't fly a barrel roll at 1g -it's impossible. And an aileron roll is just that - a roll actuated by ailerons only. And in nearly all types, this will leave you nose low when completed. A slow roll is where the nose points at a spot on or above the horizon without deviating, the aircraft completes the manoeuvre without height loss. To do this, at some stage you will be flying inverted and be at -1g. This is not an elevator or rudder neutral manoeuvre - co-ordinated use of all controls is necessary to keep the aircraft level.
Some people think that barrell rolls are difficult. They are a lot easier that slow rolls. At a school I instructed at, the barrell roll was the second aeroabtic manoeuvre (after the loop) taught to the students, the slow roll coming much later. It can't have been that hard as they were usually cleared to fly them solo by 30hrs total time.
But whatever you call your rolls, anyone who aerobats a C172 is a ###t!
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Knox, you may have missed something here and there. Have you ever done barrel rolls and aileron rolls yourself?
You lifted this quote from the IAC website:
But what you missed is that almost everybody who flies aerobatics competitions on a serious level (what the IAC is all about), flies aircraft with symmetric aerofoils and inverted flight systems, and expects to be inverted about 50% of the time. Because of this, they TRIM the aircraft for 0g (yes, zero, so requiring a positive pull to maintain straight and level) before starting the aeros sequence.
So when they "neutralize the elevator", they actually start flying a ballistic, 0g flight path. With a roll rate, typically, approaching or even exceeding 360 degrees per second it's good enough to pitch up, center the elevator and rudder and just roll the aircraft with the ailerons. For a slow/hesitation roll however, or to prevent the nose from wobbling (through torque effects, p factor and whatnot), little deflections of both elevator and rudder make the manoeuvre neater, but also induce sideways forces and negative g's. Definitely something that makes you spill your drinks.
Bob Hoover did not do an aileron roll. And I also don't think he did a proper barrel roll, but it's very hard to tell from the video. What it looks like, to me, is what we call a "students roll". It looks almost the same from the ground, you experience the same positive g throughout, but it doesn't require the same precise coordination between pitch and roll as a barrel roll. It goes like this: dive to get some speed (130 knots), pull straight up to 60 degrees (about a 2-3 g pullup), once at 60 degrees (you are below Va then) neutralize the pitch (but I'm still at the level where we trim for 1g, so at this point I'm just doing 1g), then roll with all your might. Stop the roll, then pull out of the 60 degree dive.
Watch the video and look at the way the sun shines on the magnetic compass. It's pitch up first and only with his nose high does he start the roll.
The students roll is not an official aerobatics manoeuvre, but it is used to get used to the physical sensations of rolling and is later developed into a slow roll or a barrel roll. Or we do a stop on top to get used to the force needed for inverted flight, the physical sensation of being inverted, and learning the reflex reaction on what to do when the engine stops (our R2160 doesn't have an inverted flight system).
You lifted this quote from the IAC website:
Aileron rolls are flown with the rudder and elevator in the neutral position during the roll. The aileron is fully deflected in the direction of the roll. This is the easiest of the rolls to fly.
The aileron roll is started by pulling the nose up to 20 - 30 degrees above the horizon. The elevator is then neutralized and the aileron fully deflected in the direction of the roll. The controls are maintained in that position till the roll is completed. After the roll is completed the nose is usually 20 - 30 degrees below the horizon.
The aileron roll is started by pulling the nose up to 20 - 30 degrees above the horizon. The elevator is then neutralized and the aileron fully deflected in the direction of the roll. The controls are maintained in that position till the roll is completed. After the roll is completed the nose is usually 20 - 30 degrees below the horizon.
So when they "neutralize the elevator", they actually start flying a ballistic, 0g flight path. With a roll rate, typically, approaching or even exceeding 360 degrees per second it's good enough to pitch up, center the elevator and rudder and just roll the aircraft with the ailerons. For a slow/hesitation roll however, or to prevent the nose from wobbling (through torque effects, p factor and whatnot), little deflections of both elevator and rudder make the manoeuvre neater, but also induce sideways forces and negative g's. Definitely something that makes you spill your drinks.
Bob Hoover did not do an aileron roll. And I also don't think he did a proper barrel roll, but it's very hard to tell from the video. What it looks like, to me, is what we call a "students roll". It looks almost the same from the ground, you experience the same positive g throughout, but it doesn't require the same precise coordination between pitch and roll as a barrel roll. It goes like this: dive to get some speed (130 knots), pull straight up to 60 degrees (about a 2-3 g pullup), once at 60 degrees (you are below Va then) neutralize the pitch (but I'm still at the level where we trim for 1g, so at this point I'm just doing 1g), then roll with all your might. Stop the roll, then pull out of the 60 degree dive.
Watch the video and look at the way the sun shines on the magnetic compass. It's pitch up first and only with his nose high does he start the roll.
The students roll is not an official aerobatics manoeuvre, but it is used to get used to the physical sensations of rolling and is later developed into a slow roll or a barrel roll. Or we do a stop on top to get used to the force needed for inverted flight, the physical sensation of being inverted, and learning the reflex reaction on what to do when the engine stops (our R2160 doesn't have an inverted flight system).
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Quote: Have you ever done barrel rolls and aileron rolls yourself?
Yes many.
Yes it is hard to tell exactly what he is doing but the pitch looks fairly normal for a aileron roll but its not a classic (text book) barrel roll either.
I do understand that he more than likely has his own very unique style.
He is a legendary pilot.
I think the point i'm trying to emphasize is that a lot of people that utilize this forum do get the two maneuvers confused.
Before I started aero's i didn't know the difference.
Knox
Yes many.
Yes it is hard to tell exactly what he is doing but the pitch looks fairly normal for a aileron roll but its not a classic (text book) barrel roll either.
I do understand that he more than likely has his own very unique style.
He is a legendary pilot.
I think the point i'm trying to emphasize is that a lot of people that utilize this forum do get the two maneuvers confused.
Before I started aero's i didn't know the difference.
Knox
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speak for yourself
Knox
"a lot of people that utilize this forum do get the two maneuvers confused."
err.....
I don't think so.
Also not sure how anyone can do a proper aileron roll with a glass of water on the cowling still intact after the manoevure.
"a lot of people that utilize this forum do get the two maneuvers confused."
err.....
I don't think so.
Also not sure how anyone can do a proper aileron roll with a glass of water on the cowling still intact after the manoevure.
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back to the original quote
back to the original quote ! a 172 did a roll today over norwich now with the outstanding roll rate of the mighty spam can it nodout took all day to get round it ! p.s got a pic of cerne abbas giant with hommer simpson next to it.