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Jan 23, 2012, 10:43 PM
Sic itur ad Astra
sparks59's Avatar
Quote:
Originally Posted by pkoury
Nobody BARREL ROLLED a 707 or 367-80..... there is a big difference between barrel rolling and aileron rolling.

....I was taught that half way through a barrel roll you were inverted and the your nose was 90 degrees off of your starting heading.
Not really a helical path then
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Jan 23, 2012, 10:52 PM
Purdue Engineering
Rocketman1092's Avatar
Quote:
Originally Posted by pkoury
Nobody BARREL ROLLED a 707 or 367-80..... there is a big difference between barrel rolling and aileron rolling.
I agree with your explanation of the differences between barrel and aileron rolls, but I do think that Tex Johnston's roll in the 367-80 was the former rather than the latter. An aileron roll would have subjected the airframe to greater negative G-load than it could handle, so a barrel roll with positive loading throughout would have been the way to go. Here's a video with Johnston's explanation of the event. You can see the helical path that the airplane follows. http://www.youtube.com/watch?v=6z_fg...eature=related
Jan 23, 2012, 11:05 PM
Rock On- Damon Atwood
dag214's Avatar
Quote:
Originally Posted by pkoury
Nobody BARREL ROLLED a 707 or 367-80..... there is a big difference between barrel rolling and aileron rolling.

A barrel roll is a maneuver in which an airplane makes a complete rotation on its longitudinal axis while following a helical path, approximately maintaining its original direction. It is sometimes described as "a combination of a loop and a roll". The G-force is kept positive (but not constant) on the object throughout the maneuver, commonly between 2-3 G, and no less than 0.5 G.

The Aileron Roll is a maneuver in which the aircraft does a full 360 revolution about its longitudinal axis. When executed properly, there is no appreciable change in altitude and the aircraft exits the maneuver on the same heading as it entered. This is commonly one of the first maneuvers taught in basic aerobatics courses. This maneuver is sometimes incorrectly referred to as a barrel roll.

I was taught that half way through a barrel roll you were inverted and the your nose was 90 degrees off of your starting heading.
Strange,

When I learn rolls in a T6 I was taught that a barrel roll was a constant G-maneuver and that is what the 367-80 did as it needed to always maintain a positive-G. I would put the nose down, go up to about 180, pull up to about 40-50 degrees and while not unloading the stick crank in aileron..... When I learn an aileron roll I would pull up to about 3-5 degrees then un-load the stick and crank in full aileron until I was back to wings level. When I was at Oshkosh in the 80's a Boeing guy told me the 367-80 was done with a positive-g and he called it a barrel roll......

We may be talking about the same thing...... But if you watch the Bob Hoover tea trick that is done with a positive-G.

Now with all that said you can perform a barrel roll with just a bit of pull up and not unloading the stick and doing the roll, you will lose a bit of altitude as the 367-80 did, but you will still maintain a positive-g and it is still a barrel roll.

DAG
Jan 23, 2012, 11:07 PM
Rock On- Damon Atwood
dag214's Avatar
Quote:
Originally Posted by Rocketman1092
I agree with your explanation of the differences between barrel and aileron rolls, but I do think that Tex Johnston's roll in the 367-80 was the former rather than the latter. An aileron roll would have subjected the airframe to greater negative G-load than it could handle, so a barrel roll with positive loading throughout would have been the way to go. Here's a video with Johnston's explanation of the event. You can see the helical path that the airplane follows. http://www.youtube.com/watch?v=6z_fg...eature=related
You beat me to it.......

DAG
Jan 24, 2012, 12:13 AM
Charlie11Niner
charlie11niner's Avatar

C-130e


Several years ago someone in our unit did a positive rate G barrel roll in one of our 62' "E" model C-130's. I wasn't on it but, several of my buddies were !!!
Jan 24, 2012, 07:59 AM
Registered User
I went with Tex Johnston's description of the maneuver he did in the dash 80 prototype and that is what I typed. He did it to a single constant positive G and was supposed to be impossible for a large aircraft like that!
Foo
Jan 24, 2012, 08:18 AM
Registered User
Mr_McGlue's Avatar
It doesn't matter what your flight instructor told you he still rolled a big plane.

IMO it wasn't an aileron roll so take your pick...

Robert

Quote:
Originally Posted by pkoury
Nobody BARREL ROLLED a 707 or 367-80..... there is a big difference between barrel rolling and aileron rolling.
Jan 24, 2012, 08:45 AM
Rock On- Damon Atwood
dag214's Avatar
Here are a few pics from late last night.

The right wing nacelles are just about ready for final sanding then glassing
I hope to have the left wing intakes don by Sunday (I am very busy this week with work).

And about the barrel roll, it was a barrel roll and not an aileron roll. If you want to take a Wikipedia definition of a barrel roll it may not by definition be a perfect one. A true barrel roll done as a maneuver will see the plane go about 90% off heading, but is on heading as you exit. BUT, any roll that hold a positive-g is a barrel roll. If you enter it from wings level and just crank in aileron and do not unload the stick you will roll but lose a ton of altitude. I have done a ton of these in T-6's and a true barrel roll is not easy if you want to nail heading and altitude. A aileron roll, hell.... just pitch up, unload, and crank in the aileron until you see wings level.

Go to 4:08 and you will see me do 2 aileron rolls and we did not hold a positive-G

AT-6 Flight (9 min 54 sec)


And this was kind of a crappy flight as the night before I had hit a few pubs with my British mates and was still feeling it.

Rock ON!!!
DAG
Jan 24, 2012, 09:33 AM
If in doubt, add accelerant
Lberry.88's Avatar
Quote:
Originally Posted by dag214
And this was kind of a crappy flight as the night before I had hit a few pubs with my British mates and was still feeling it.

Rock ON!!!
DAG
Us Brits can do that! Nacelles look great Dag. Keep rocking!

Luke
Jan 24, 2012, 09:43 AM
soaring guy
Hi Dag,

What is the white material you using to fair the inlets to the wing?

Dee
Jan 24, 2012, 10:20 AM
Registered User
coptercptn's Avatar
Quote:
Originally Posted by dag214
Strange,

When I learn rolls in a T6 I was taught that a barrel roll was a constant G-maneuver and that is what the 367-80 did as it needed to always maintain a positive-G. I would put the nose down, go up to about 180, pull up to about 40-50 degrees and while not unloading the stick crank in aileron..... When I learn an aileron roll I would pull up to about 3-5 degrees then un-load the stick and crank in full aileron until I was back to wings level. When I was at Oshkosh in the 80's a Boeing guy told me the 367-80 was done with a positive-g and he called it a barrel roll......

We may be talking about the same thing...... But if you watch the Bob Hoover tea trick that is done with a positive-G.

Now with all that said you can perform a barrel roll with just a bit of pull up and not unloading the stick and doing the roll, you will lose a bit of altitude as the 367-80 did, but you will still maintain a positive-g and it is still a barrel roll.

DAG
That was how we accomplished it in a CH-53a Helicopter @ Pax... Sikorsky said it "could" be done so we had to try it.... Having a fully articulated head, you HAVE to keep positive G's or the whole deal folds up on you!!!!!
Jan 24, 2012, 10:21 AM
Registered User
Brilliant!

I'm a little late to the party here, but I've just seen the drop test videos. I'm a landing gear dynamics engineer by trade (I was involved in the drop testing of the newest airliner to come out of the Seattle area, among numerous other airplanes) so I'd just like to say kudos to you! Great vids, keep up the good work. I only wish I had the time and patience to accomplish something like this.

Cheers
Chris
Jan 24, 2012, 02:16 PM
I fly, therefore, I crash!!!
SteveT.'s Avatar
Quote:
Originally Posted by dwood75
Hi Dag,

What is the white material you using to fair the inlets to the wing?

Dee
I'm not Dag, but I would bet it is light weight "spackle"... If so, you can buy it at any hardware store. I use the stuff that is pink in the container but turns white when dry. It's easy to sand, and you can wet your finger, and smooth it out very nicely... However, it adds no strength. For a light weight filler that does add a small amount of strength, you can use "microballoons" or even milled fiberglass mixed with polyester resin. Both of these fillers are usually available at any good LHS.

SteveT
Last edited by SteveT.; Jan 24, 2012 at 02:47 PM.
Jan 24, 2012, 02:42 PM
Rock On- Damon Atwood
dag214's Avatar
Quote:
Originally Posted by spiragui
Brilliant!

I'm a little late to the party here, but I've just seen the drop test videos. I'm a landing gear dynamics engineer by trade (I was involved in the drop testing of the newest airliner to come out of the Seattle area, among numerous other airplanes) so I'd just like to say kudos to you! Great vids, keep up the good work. I only wish I had the time and patience to accomplish something like this.

Cheers
Chris
Thanks!!!

DAG
Jan 24, 2012, 02:43 PM
Rock On- Damon Atwood
dag214's Avatar
Quote:
Originally Posted by dwood75
Hi Dag,

What is the white material you using to fair the inlets to the wing?

Dee
It is light weight spackle with micro balloons, and some times saw dust.....

Thanks, DAG


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