60 years ago: The famous Boeing 707 prototype barrel roll over Lake Washington

a reply to: verschickter
I don't know the G limits on 707 but FAA says the a transport category plane can be as low as 2.5 Gs positive and 1.75 G negative IIRC. This is a design consideration by the manufacturer. Most of the plane that I have flown as a civilian was in the utility category with 4 G pos. and 2 G neg. and in the military they were stressed to 6 G pos and 3 G neg.

If the barrel roll is done correctly it is a 1 G maneuver which is OK. There is a formula for figuring stress in a maneuver but I can't remember it at the moment.

originally posted by: TheWhiteKnight


But what about Travolta, or Cruise? Doesn't one of these guys own their own jumbo jets? The hell….if anyone could it'd be these guys.

a reply to: verschickter

# 491

Travolta owns a 707

a reply to: TheWhiteKnight

The 707 wasn't a jumbo.

At the time that it was rolled, they hadn't sold any, and had sunk a lot of money into the program. It was up against some stiff competition. After the roll several airlines expressed interest and it started selling.

Boeing now has the reputation that just about anything they build will sell in large numbers. Back then they didn't have that reputation.

originally posted by: TheWhiteKnight


But what about Travolta, or Cruise? Doesn't one of these guys own their own jumbo jets? The hell….if anyone could it'd be these guys.

a reply to: verschickter

# 491

Travolta owns a 707. It's not a "jumbo jet" but it is a transport category jet airliner.

this feat is legend, but ive never seen it on film....just WOW!!!

originally posted by: buddah6
a reply to: verschickter
I don't know the G limits on 707 but FAA says the a transport category plane can be as low as 2.5 Gs positive and 1.75 G negative IIRC. This is a design consideration by the manufacturer. Most of the plane that I have flown as a civilian was in the utility category with 4 G pos. and 2 G neg. and in the military they were stressed to 6 G pos and 3 G neg.

If the barrel roll is done correctly it is a 1 G maneuver which is OK. There is a formula for figuring stress in a maneuver but I can't remember it at the moment.

The design load limits are not the only consideration. With a 35 degree wing sweep, the 707 is very susceptable to roll coupling which can lead to violent rolling and yawing motions. In fact, before Boeing added yaw dampers to production aircraft, one of the brand new 707s ripped 2 engines off the wings ad crash-landed killing 4 people.

a reply to: bigx001

Technically, what the Dash 80 did is more properly called an aileron roll and not a barrell roll. In a true barrell roll, the pitch angle approaaches vertical. In a true barrell roll the design load limits would probably be exceeded during the last 30 degrees or so of roll. An aileron roll can be a true 1 G all the way around manuever and, if done correctly, adverse yaw side loads are avoided. www.youtube.com... is an example of this.

originally posted by: F4guy

originally posted by: buddah6
a reply to: verschickter
I don't know the G limits on 707 but FAA says the a transport category plane can be as low as 2.5 Gs positive and 1.75 G negative IIRC. This is a design consideration by the manufacturer. Most of the plane that I have flown as a civilian was in the utility category with 4 G pos. and 2 G neg. and in the military they were stressed to 6 G pos and 3 G neg.

If the barrel roll is done correctly it is a 1 G maneuver which is OK. There is a formula for figuring stress in a maneuver but I can't remember it at the moment.

The design load limits are not the only consideration. With a 35 degree wing sweep, the 707 is very susceptable to roll coupling which can lead to violent rolling and yawing motions. In fact, before Boeing added yaw dampers to production aircraft, one of the brand new 707s ripped 2 engines off the wings ad crash-landed killing 4 people.

Was the roll coupling caused during steep turns or aerobatic flight? Was it during certification?

So what is it now, aileron or barrel-roll? Tex himself called it a "short barrel roll".
Where does one start to differ between those two? I know how they are described both.
If you reduce it to that, an aileron roll would be a tiny barrel roll also, because you end up in pitch movements unvoluntary/have to pull up nose to not loose altitude

originally posted by: F4guy
a reply to: bigx001

Technically, what the Dash 80 did is more properly called an aileron roll and not a barrell roll. In a true barrell roll, the pitch angle approaaches vertical. In a true barrell roll the design load limits would probably be exceeded during the last 30 degrees or so of roll. An aileron roll can be a true 1 G all the way around manuever and, if done correctly, adverse yaw side loads are avoided. www.youtube.com... is an example of this.

All of my aerobatic flight was in straight wing aircraft and they were fairly docile even with wing stores. IIRC we did the barrel rolls at around 1 G but I wasn't a fighter jock who practice aerobatics as a normal routine. In fact, in the 14 years that I flew the Mohawk, I can only remember a handful of times it was in a clean configuration as to be able to do full aerobatics.

Great thread guys,
S&F.

Where's Weedwhacker these days ?

Fox.

originally posted by: verschickter
So what is it now, aileron or barrel-roll? Tex himself called it a "short barrel roll".
Where does one start to differ between those two? I know how they are described both.
If you reduce it to that, an aileron roll would be a tiny barrel roll also, because you end up in pitch movements unvoluntary/have to pull up nose to not loose altitude

I was taught that an aileron roll was with the nose of the airplane was on a single point on the horizon and a barrel roll starts with an attitude of 10 to 15 degrees above the horizon. A barrel roll can be performed with a steeper attitude were the airplane is in the near vertical entry and a near vertical exit to the maneuver.

Aileron roll ...G=1/cosine of the angle of bank in degrees...I think. G=1/.5= 2G at 60 degree bank.

originally posted by: buddah6

originally posted by: F4guy

originally posted by: buddah6
a reply to: verschickter
I don't know the G limits on 707 but FAA says the a transport category plane can be as low as 2.5 Gs positive and 1.75 G negative IIRC. This is a design consideration by the manufacturer. Most of the plane that I have flown as a civilian was in the utility category with 4 G pos. and 2 G neg. and in the military they were stressed to 6 G pos and 3 G neg.

If the barrel roll is done correctly it is a 1 G maneuver which is OK. There is a formula for figuring stress in a maneuver but I can't remember it at the moment.

The design load limits are not the only consideration. With a 35 degree wing sweep, the 707 is very susceptable to roll coupling which can lead to violent rolling and yawing motions. In fact, before Boeing added yaw dampers to production aircraft, one of the brand new 707s ripped 2 engines off the wings ad crash-landed killing 4 people.

Was the roll coupling caused during steep turns or aerobatic flight? Was it during certification?

It occurred during dutch roll training manuevers where the aircraft is rolled one direction with no yaw and then reversed. The fatal accident was on a production aircraft. I think it was serial 227 but I may not remember correctly.

a reply to: F4guy

That happened to a -135 in Desert Storm only they were able to land. The other two mounts suffered a good bit of damage. They got into a Dutch roll and lost two engines on one side.

a reply to: F4guy

Boeing 707-227, N7071, c/n 17691.

www.failure-interactions.com...

aviation-safety.net...

originally posted by: buddah6
Aileron roll ...G=1/cosine of the angle of bank in degrees...I think. G=1/.5= 2G at 60 degree bank.

That formula is for computing wing loading in a level coordinated turn, not a roll. A 60 degree banked level coordinated (no slip or skid) turn will give you 2 Gs. 80 degrees gives you 6 Gs. From there it increases asymptotically toward infinity. It is possible and attainable to do a full aileron roll at +1g throughout. A barrell roll, on the other hand begins with a vigerous pull with 2.5-3.5 gs, a relaxation of the pull toward neutral at the inverted point giving 0-.5gs over the top and then a hefty pull to level with, again, +2-3gs.

originally posted by: F4guy

originally posted by: buddah6
Aileron roll ...G=1/cosine of the angle of bank in degrees...I think. G=1/.5= 2G at 60 degree bank.

That formula is for computing wing loading in a level coordinated turn, not a roll. A 60 degree banked level coordinated (no slip or skid) turn will give you 2 Gs. 80 degrees gives you 6 Gs. From there it increases asymptotically toward infinity. It is possible and attainable to do a full aileron roll at +1g throughout. A barrell roll, on the other hand begins with a vigerous pull with 2.5-3.5 gs, a relaxation of the pull toward neutral at the inverted point giving 0-.5gs over the top and then a hefty pull to level with, again, +2-3gs.

I'm from Kentucky so let me take my shoes off to get my hillbilly abacus out. G= 1/ cosine of 80 degrees...g= 1 divided by .1754= 5.76 Gs. Damn that's pretty close.

A 3.5 G pull starts to puts an old bastard like me to sleep...we didn't wear gravity pants but we did HICK a bit. I think we are talking about two airplanes with vastly different performance envelopes.

originally posted by: verschickterack to level with the result that the aircraft
So what is it now, aileron or barrel-roll? Tex himself called it a "short barrel roll".
Where does one start to differ between those two? I know how they are described both.
If you reduce it to that, an aileron roll would be a tiny barrel roll also, because you end up in pitch movements unvoluntary/have to pull up nose to not loose altitude

It depends a little on whose doing the defining. When I first began international precision aerobatic competitions the barrell roll was a compulsory figure in the known program. The criterion was that it was a constant angular momentum pitch change of 360 degrees (a loop) integrated with constantly increasing bank to 180 degrees and then constantly decreasing bank back to level with the result that the aircraft finished the figure or manuever 90 degrees off heading to the entry heading. There was no figure delineated as an aileron roll, but the closest thing was a "slow" roll which is a full 360 degree roll with constant roll rate and constant flight track. What the nose does during this roll depends on airfoil section (symetrical v. high cambered) and angle of incidence of the wing. The g loading for this roll starts at +1, goes to 0 (actually +1 laterally) at 90 degrees bank, to -1 at inverted(where it gets really quiet because unless you have fuel injection or a pressure carb and a header tank system the engine quits) and back to +1 at the end. And then you have the "snap" roll, which is an accelerated stall autorotation on a constant heading and constant altitude, unless you are doing the snap on a vertical up or down line. In the Sukhoi I would routinely see +9 gs on mutiple inside snaps and -9 on outside snaps

originally posted by: F4guy

originally posted by: verschickterack to level with the result that the aircraft
So what is it now, aileron or barrel-roll? Tex himself called it a "short barrel roll".
Where does one start to differ between those two? I know how they are described both.
If you reduce it to that, an aileron roll would be a tiny barrel roll also, because you end up in pitch movements unvoluntary/have to pull up nose to not loose altitude

It depends a little on whose doing the defining. When I first began international precision aerobatic competitions the barrell roll was a compulsory figure in the known program. The criterion was that it was a constant angular momentum pitch change of 360 degrees (a loop) integrated with constantly increasing bank to 180 degrees and then constantly decreasing bank back to level with the result that the aircraft finished the figure or manuever 90 degrees off heading to the entry heading. There was no figure delineated as an aileron roll, but the closest thing was a "slow" roll which is a full 360 degree roll with constant roll rate and constant flight track. What the nose does during this roll depends on airfoil section (symetrical v. high cambered) and angle of incidence of the wing. The g loading for this roll starts at +1, goes to 0 (actually +1 laterally) at 90 degrees bank, to -1 at inverted(where it gets really quiet because unless you have fuel injection or a pressure carb and a header tank system the engine quits) and back to +1 at the end. And then you have the "snap" roll, which is an accelerated stall autorotation on a constant heading and constant altitude, unless you are doing the snap on a vertical up or down line. In the Sukhoi I would routinely see +9 gs on mutiple inside snaps and -9 on outside snaps

I think where we disagree is that you are flying an airplane with neutral dynamic stability and I flew an airplane with positive dynamic stability. You have to force your plane through maneuvers and my bird wants to correct itself without inputs from me. Your plane stays where you point it and that's why you pull negative Gs at the top of your roll. Just a guess.