A aviation & planes forum. AviationBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AviationBanter forum » rec.aviation newsgroups » Aerobatics
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Path of an airplane in a 1G roll



 
 
Thread Tools Display Modes
  #11  
Old June 20th 05, 01:53 PM
Roy Smith
external usenet poster
 
Posts: n/a
Default

In article , Bob Fry
wrote:

"BC" == Byron Covey writes:


BC You can't do a roll and retain 1 G positive throughout the
BC roll. BJC

There's supposed to be a video of the great Bob Hoover doing a barrel
roll with a glass of water on the panel...not a drop spilled. If
anybody knows where a copy of the video is (or if it even exists) that
would be a worth addition to Jay Honeck's collection.


All that shows is that he maintained positive G's and coordination.
Ads
  #12  
Old June 21st 05, 04:09 AM
Chris W
external usenet poster
 
Posts: n/a
Default

David O wrote:

Chris W wrote:



Do we have any who is a math whiz here? I want to find a formula to
calculate the position of an airplane throughout a 1G roll. The reason
I'm doing this is so I can build a "roll track" for a remote control car
so the car will alway have a positive g force on it to keep it on the
track. Anyone have any ideas? So far my attempts have have all come up
short. They don't pass what my college calculus instructor called the
"warm and fuzzy" test. I think it has been too long since I took those
classes.



Chris,

I suggest that you forget about trying to model the path of an
airplane in a 1 G roll and, instead, make your car track a simple
helix. With a simple helix you should be able to keep your car's
front wheels straight as the car goes through the helix. Now for the
details...


Why didn't I think of that. That is a much simpler solution. I can
even do those calculations but thanks for doing them for me. If I get a
3d model going I will send you an image.

--
Chris W

Gift Giving Made Easy
Get the gifts you want &
give the gifts they want
http://thewishzone.com
  #13  
Old June 22nd 05, 02:01 AM
David O
external usenet poster
 
Posts: n/a
Default

Chris W wrote:

If I get a
3d model going I will send you an image.


Yes, please do.

David O -- email: David at AirplaneZone dot com


  #14  
Old June 22nd 05, 07:37 PM
CB
external usenet poster
 
Posts: n/a
Default

A properly performed barrel roll is a 1G manuever. The aircraft's
flight path describes a helix, as David described below. An aileron
roll is a variable-G operation, since you feel -1G while inverted.

  #15  
Old June 22nd 05, 07:47 PM
Ron Natalie
external usenet poster
 
Posts: n/a
Default

CB wrote:
A properly performed barrel roll is a 1G manuever.


Nope. It's a small amount of positive G's but it's not a constant
1G. Did you actually read David's post?
  #16  
Old June 22nd 05, 09:09 PM
Bob Moore
external usenet poster
 
Posts: n/a
Default

"CB" wrote
A properly performed barrel roll is a 1G manuever. The aircraft's
flight path describes a helix, as David described below. An aileron
roll is a variable-G operation, since you feel -1G while inverted.


Check the following web sites, they all contain the same paragraph.
Care to give us your references for the definition of a barrel roll.

http://www.iac.org/begin/figures.html#Barrel%20Rolls
http://acro.harvard.edu
http://web.winco.net/~efildes/slowroll/barlroll.html
The Barrel Roll is a not competition maneuver. 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 experiences always positive G's. The
maximum is about 2.5 to 3 G, the minimum about 0.5 G.

Bob Moore
  #17  
Old June 23rd 05, 09:21 PM
Happy Dog
external usenet poster
 
Posts: n/a
Default

"CB" wrote in message

A properly performed barrel roll is a 1G manuever. The aircraft's
flight path describes a helix, as David described below.


No.

An aileron
roll is a variable-G operation, since you feel -1G while inverted.


No.

Ever done one?

moo


  #18  
Old June 27th 05, 05:46 PM
CB
external usenet poster
 
Posts: n/a
Default

OK, folks, brace yourselves, you don't often see this on RAH....


I was wrong.


That's what I get for relying on an aging memory rather than looking it
up.
CB

  #19  
Old June 27th 05, 07:22 PM
Roger
external usenet poster
 
Posts: n/a
Default

On Sun, 19 Jun 2005 11:04:39 -0500, Chris W wrote:

4 Groups?

Do we have any who is a math whiz here? I want to find a formula to
calculate the position of an airplane throughout a 1G roll. The reason


At any rate, do you want to maintain 1G, or just positive G? it's a
big difference.

You can do a barrel roll and maintain positive G all the way around.
It's a very simple maneuver and very easy to do. It's also probably
one of the easiest to screw up.

I'm doing this is so I can build a "roll track" for a remote control car


Remember that in straight and level flight you are pulling 1G. If you
start a roll you will have to start adding nose up stick to maintain
1G to the point of 1G when inverted. "
"Theoretically" as you rolled past inverted you would start reducing
back pressure until you were back wings level.

At this point it takes some one much more versed in aeronautic theory
(and practice) than I, but... A barrel roll comes the closest to what
you are asking. It, however starts out at more than 1G. Typically 2Gs
and it can be more. With a 2G pull up at the start, you will be
pulling 1G when passing inverted.

Remember you started out in a nose high attitude to get to this point.
So in the theoretically description you would most likely be way nose
low at the 180 degree inverted position and I think you will probably
get well past 2 Gs getting back to the wings level position.

so the car will alway have a positive g force on it to keep it on the


But, if it's just the positive Gs you need, shape the track like the
path a plane would take through a barrel roll. It would go up and
curve to the right forming a corkscrew shape with the end right back
at the same level as the beginning. You can add turns as well "as
long as the car is changing direction in relation to *its" own
vertical axis. For example if the car is on its right side the track
needs to be curving right, if on its left then the track needs to be
curving left. If the car is inverted the track needs to be curving
down.

Remember too that the car has to be going fast enough to maintain the
desired G forces and traction. Slow down and it'll just fall off.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
track. Anyone have any ideas? So far my attempts have have all come up
short. They don't pass what my college calculus instructor called the
"warm and fuzzy" test. I think it has been too long since I took those
classes.


  #20  
Old June 29th 05, 04:01 AM
Ernest Christley
external usenet poster
 
Posts: n/a
Default

My take on this is that an airplane in a 1G roll would follow the same
path as any other object.

Imagine your in space. A 1G roll would be a perfect circle with a
constant 1G acceleration.

Now bring that path into the Earth's gravity well. Now the 1G roll is
all messed up by the Earth's 1G. How can we fix that? Just like the
Vomit Comet does, by accelerating down at 9.8m/s^2. Superimpose a roll
on top of a parabolic descent and you have the path of a theoretical
airplane in a 1G roll.

I don't think there is a plane that could actually perform this maneuver
in reality.

--
This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Parachute fails to save SR-22 Capt.Doug Piloting 72 February 10th 05 05:14 AM
"I Want To FLY!"-(Youth) My store to raise funds for flying lessons Curtl33 General Aviation 7 January 9th 04 11:35 PM
Rolling a 172 - or not Scott Lowrey Piloting 55 November 16th 03 12:15 AM
rec.aviation.aerobatics FAQ Dr. Guenther Eichhorn Aerobatics 0 September 1st 03 07:27 AM
rec.aviation.aerobatics FAQ Dr. Guenther Eichhorn Aerobatics 0 August 1st 03 07:27 AM


All times are GMT +1. The time now is 06:23 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright 2004-2018 AviationBanter.
The comments are property of their posters.