Inverted Flight - Rudder does reverse
tim.p...@cciw.ca
An errant post earlier got my attention. A new aerobatics pilot was asking
what controls are reversed in inverted flight, and someone posted to say that
only elevator became reversed. However, the fact is, RUDDER reverses as well.
Inveretd, left rudder will cause pilot-perceived yaw to the right, and right
rudder a perceived yaw to the left. Perhaps from the miniature pilot's view,
left is still left, but standing on the ground, that is not the case.
Hence the difficulty for many pilots in making rudder course corrections
during inverted aerobatic maneuvers. Please people, if you are posting to try
and educate novice pilots, please make sure you know what you are saying first
- this type of crap isn't fair for people trying to ask basic questions about
flight, and get basic Correct answers back.
Tim
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Im1bad1
tim.p...@cciw.ca spewed:
> However, the fact is, RUDDER reverses as well.
Well, is that really a fact? Even you contradicted it later in your post.
>- this type of crap isn't fair for people trying to ask basic questions
> about flight.......
I couldln't have said it better myself.
Tom in PGH AMA 10397
tim.p...@cciw.ca
In article <199804061417...@ladder03.news.aol.com>,
im1...@aol.com (Im1bad1) wrote:
>
> Well, is that really a fact? Even you contradicted it later in your post.
>
> Tom in PGH AMA 10397
>
>
Well, actually, I think I said that it might not appear to reverse, if you
were inside the aircarft. But that isn't really an option in a model.... As
R/C pilots, we have to work with the frame of reference that we have, which is
outside the aircraft from the ground. And from this frame, rudder reverses
it's perceived action on the aircraft when the aircraft is inverted.
AJDalton7
Just as it is reversed coming back at you !
Arthur
Molitor
Read your own post and take your own advice. THE RUDDER DOES NOT
REVERSE. If this was so, a rudder induced roll would never make it
past half way. Quit thinking from an external perspective and you will
be ok. Left is left and Right is right. PERIOD
sk
tim.p...@cciw.ca wrote:
> An errant post earlier got my attention. A new aerobatics pilot was
> asking
> what controls are reversed in inverted flight, and someone posted to
> say that
> only elevator became reversed. However, the fact is, RUDDER reverses
> as well.
> Inveretd, left rudder will cause pilot-perceived yaw to the right, and
> right
> rudder a perceived yaw to the left. Perhaps from the miniature pilot's
> view,
> left is still left, but standing on the ground, that is not the case.
> Hence the difficulty for many pilots in making rudder course
> corrections
> during inverted aerobatic maneuvers. Please people, if you are posting
> to try
> and educate novice pilots, please make sure you know what you are
> saying first
> - this type of crap isn't fair for people trying to ask basic
> questions about
> flight, and get basic Correct answers back.
>
Harry Curzon
tim.p...@cciw.ca wrote:
> Well, actually, I think I said that it might not appear to reverse, if you
> were inside the aircarft. But that isn't really an option in a model.... As
> R/C pilots, we have to work with the frame of reference that we have, which is
> outside the aircraft from the ground. And from this frame, rudder reverses
> it's perceived action on the aircraft when the aircraft is inverted.
>
> Tim
Tim, you are right and wrong, and wrong and right! Let's sort this
out. There are 2 frames of reference, 1. the plane's, 2. the ground
observer or model pilot. Aerodynamically, the plane does not know of
up, down, etc, all it knows is the airflow around it. Aerodynamically,
gravity or orientation to anything else is not a variable in the
equation. From the plane's point of view, left rudder produces left
yaw. With sufficient dihedral there is a secondary effect of yaw,
namely roll. From the plane's frame of reference the roll will always
be in the direction of yaw. So, from the plane's reference, left rudder
on the pedals or Tx stick = left rudder at the tail = left yaw = left
roll. Okay so far?
Now lets' look at the model pilot's reference. Left rudder when the
model is inverted looks the same as right rudder on an upright model.
This produces a yaw to the model pilot's right (but still a yaw to the
left for the onboard pilot). So far your analysis was correct Tim.
Where you went wrong was thinking that right yaw caused right roll when
inverted. The big difference now from the model pilot's reference is
that the model no longer has dihedral, but anhedral. Anhedral works the
opposite way to dihedral, so a yaw will produce a roll in the opposite
direction. Thus from the model pilot's reference, left rudder at the Tx
= right rudder on the model = left roll.
What this will lead to is that if you try flying a 3 function model
inverted, the turns will be un-cordinated, since the rudder will be
trying to point the plane out of the turn. A large slip will occur and
this will act on the fin to turn the plane back into the turn, a force
being balanced at some point by the rudder.
The big error as always is in thinking that a plane's aerodynamic
controls and aerodynamic effects somehow know where the ground is. They
don't!
Harry
Molitor
<snip>
> The big error as always is in thinking that a plane's aerodynamic
> controls and aerodynamic effects somehow know where the ground is.
> They
> don't!
>
> Harry
Harry
After reading and re-reading this thread, I think you nailed the
confusion right on the head. Thanks for taking the time to state the
(not so) obvious.
Scott
Ccmclain
>THE RUDDER DOES NOT
>REVERSE.
I think the confusion results from the two reactions caused by the application
of rudder on certain planes.
1. Yaw. It reverses, the direction of yaw caused by the rudder does change
half way through a roll.
2. Roll. Doesn't reverse, in a plane designed to roll with rudder, the
direction of roll does not change half way through.
On a pattern style plane, there is practically no roll caused by the rudder, so
it is correct to say that rudder reverses when inverted. On a trainer style
plane, designed to roll with rudder, it is correct to say that rudder does not
reverse when inverted.
Only my opinion, I could be wrong.
Chris
Jim Gill
"Molitor at SKnu...@localaccess.com wrote the following message on Mon, 06 Apr 1998 11:55:08 -0700:"> Read your own post and take your own advice. THE RUDDER DOES NOT
about aerobatic planes while some are talking about trainers.
A properly set up aerobatic plane does not roll with rudder and only
yaws. In this case the rudder will reverse when inverted.
Most trainers have dihedral and will roll when rudder is used as well
as yaw. If there is enough dihedral then the rudder will still turn it in the same
direction as when upright. (I know this from experience with 2
channel soarers)
Before people start to flame each other please make sure that you are
both talking about the same setup. It sometimes helps to read the
whole thread and not just comment on the last entry.
setup
--
Jim
Dundee Model Aircraft Club
http://home.clara.net/wbruce.ogilvy/
Scottish Aeromodellers Association
tim.p...@cciw.ca
Molitor,
You really need to read what I wrote. I did specify that from the
plane’s perspective (Perhaps from the miniature pilot's view, left is still
left, but standing on the ground, that is not the case) the rudder always
maintains its directional characteristics. BUT - we do not fly model airplanes
from inside, and by definition must deal with a different frame of reference
than from inside the cockpit! By your argument, elevator does not ‘really’
reveres either when inverted, because it still makes the nose of the aircraft
pitch in the same direction relative to the tail. We all know, though, that in
a low inverted pass, pushing on the stick will not help the situation; and
aileron doesn’t reverse (our perception, remember) when the plane is coming at
us……? When performing a cuban eight, inverted stall turn, or outside loop,
PERCEIVED YAW will require OPPOSITE RUDDER from what we traditionally apply in
‘upright’ maneuvers.
Come on Molitor, lets mot confuse the new pilots with this type of
pointless argument. We all know that if we were in the plane, perceptions
would be much different - but that just isn’t the case.
Tim
In article <3529250C...@localaccess.com>,
Molitor <SKnu...@localaccess.com> wrote:
>
> Read your own post and take your own advice. THE RUDDER DOES NOT
> REVERSE. If this was so, a rudder induced roll would never make it
> past half way. Quit thinking from an external perspective and you will
> be ok. Left is left and Right is right. PERIOD
>
> sk
-----== Posted via Deja News, The Leader in Internet Discussion ==-----
Harry Curzon
Ccmclain wrote:
>
> >THE RUDDER DOES NOT
> >REVERSE.
>
But you are absolutely correct! These posts really got going following
questions about how rudder affects roll on a 3 function plane when
inverted, which is why the replies have concentrated mainly on the
yaw/roll coupling rather than yaw alone.
Harry
Ocram
Sorry Tim, but I bet you never tried to fly upside down with a plane that
has only rudder/elevator/throttle and NO ailerons. Like my trainer Robbe
Charter for instance.
I do it every week, flying upside down, and first I tried to do it your way,
but it did not work. Now I do inverted low passes with my crummy Charter
every weekend, an I found out that left remains left and right remains
right. So this explanation below is WRONG.
Please also read the theoretical explanation of mr. Harry Cruzon posted as a
reply to this yesterday.
Marco
tim.p...@cciw.ca heeft geschreven in bericht
<6gamcl$9nv$1...@nnrp1.dejanews.com>...
>An errant post earlier got my attention. A new aerobatics pilot was asking
>what controls are reversed in inverted flight, and someone posted to say
that
>only elevator became reversed. However, the fact is, RUDDER reverses as
well.
>Inveretd, left rudder will cause pilot-perceived yaw to the right, and
right
>rudder a perceived yaw to the left. Perhaps from the miniature pilot's
view,
>left is still left, but standing on the ground, that is not the case.
> Hence the difficulty for many pilots in making rudder course corrections
>during inverted aerobatic maneuvers. Please people, if you are posting to
try
>and educate novice pilots, please make sure you know what you are saying
first
>- this type of crap isn't fair for people trying to ask basic questions
about
>flight, and get basic Correct answers back.
>
>Tim
>
Beavis
In article <199804061751...@ladder03.news.aol.com>, AJDalton7
<ajda...@aol.com> writes
>Just as it is reversed coming back at you !
> Arthur
But Arthur, if it's upside down AND coming back towards you all's well
again:-)
You wanna try this with a helicopter!!
Beav
--
E-mail me (if you want to) at
Beavis AT nachos dot Demon dot co dot uk
AJDalton7
>But Arthur, if it's upside down AND coming back towards you all's well
>again:-)
Not if you'r standing on your Head !!
Arthur
Gerald43
> please make sure you know what you are saying first
>- this type of crap isn't fair
If I answered his post, I'm sure I replied correctly. Pardon the hell outta
all of us who make mistakes, Tim!!!!!! I'm SURE you've NEVER made a mistake or
given incorrect advice in error! When you become perfect, we'll elect you God!
Gera...@aol.com
"Batman"
Rockett Crawford
I am seeing a lot of angry posts over this and I think it simply
boils down to whether the airplane has significant dihedral.
Tim is right on planes with little or no dihedral. The RC plane will
seem (to the RC pilot) to yaw the opposite direction when it is
upside down. Please note that I am talking about yaw and not roll.
If a plane has enough dihedral for the rudder to induce roll.
This roll will be in the same direction whether the plane is
right side up or upside down to the RC pilot.
Bottom line is yaw seems reversed but roll isn't.
Rockett Crawford
tim.p...@cciw.ca wrote:
>
> An errant post earlier got my attention. A new aerobatics pilot was asking
> what controls are reversed in inverted flight, and someone posted to say that
> only elevator became reversed. However, the fact is, RUDDER reverses as well.
> Inveretd, left rudder will cause pilot-perceived yaw to the right, and right
> rudder a perceived yaw to the left. Perhaps from the miniature pilot's view,
> left is still left, but standing on the ground, that is not the case.
> Hence the difficulty for many pilots in making rudder course corrections
> during inverted aerobatic maneuvers. Please people, if you are posting to try
> and educate novice pilots, please make sure you know what you are saying first
Joe L.
Molitor wrote:
>
> Read your own post and take your own advice. THE RUDDER DOES NOT
> REVERSE. If this was so, a rudder induced roll would never make it
> past half way. Quit thinking from an external perspective and you will
> be ok. Left is left and Right is right. PERIOD
>
> sk
>
I'm re-posting the answer I gave to Chin Tang back on Dec.31, 1997 in
hopes of clearing up some of the confusion for the novices. It's right
out of an R/C flight training manual (see reference below) and should
settle the debate once and for all.
I included Chin Tang's question and my reply. I hope this helps.
Chin Tang wrote:
>
> Hi:
>
> I was at the field today. I wanted to start flying inverted
> pretty soon on my super sporster. I was told that when inverted, the
> airleron turns and banks stay the same while rudder control is opposite.
> Of course, it goes without saying that the elevator is opposite.
>
> I can't make sense of the rudder controls. Is the rudder control
> opposite when you fly inverted? How could it be? consider a plane with
> only three channels. If you tried to do a rudder roll on such a plane,
> you would have a plane that rolls only 180 degrees and then roll 180
> degrees back the other way.
>
> Please help. Exactly how are the controls different when you fly
> inverted? I really want to start flying inverted as soon as possible.
> So, please give me a definitive answer right away. Also, if you could,
> please explain the logic behind the change or lack there of change of the
> rudder.
>
> sincerely, cheers.
Hi Chin Tang, Here's some help from RCM's Flight training Course Vol.
II, by Ben Strasser and Tom Cone. It's a good book for learning
maneuvers, step-by-step. Although first published in 1974, I think it's
still available from Radio Control Modeler magazine (RCM).
I'm quoting right from the book:
When the plane is inverted, the elevator is backward. Down elevator
makes the plane climb. Up elevator makes the plane dive. And, when your
plane is properly trimmed, you will need to ride some down elevator to
maintain altitude when you're flying inverted.
With the plane upside down the ailerons work as they normally do. Right
stick, right bank, etc. In flying inverted you'll have to use the
ailerons to maintain your heading, just as you do when you fly
right-side-up.
While you probably won't be using your rudder for your inverted flight,
( my words here....unless of course you do not have ailerons), you
should know that when the plane is inverted, the rudder works opposite.
You can see that if you use rudder trim for straight and level flight,
that trim will be working against you when you are inverted.
And, don't forget that you'll need some altitude for insurance as you
get into it.
My thoughts: These instructions are still valid today as they were back
in 1974 , when the book was copyrighted. Most radio control airplane
flyers think of using the controls on their transmitters in these
manners for controlling their models.
Joe L.
=====
Words to live by: Do not argue with a spouse who is packing your
parachute.
Beavis
In article <199804072312...@ladder03.news.aol.com>, AJDalton7
<ajda...@aol.com> writes
Bugger!! I forgot about that :-)
AJDalton7
>Bugger!! I forgot about that :-)
>
>Beav
Beav,
That's what thoes little servo reverse switches must be for!!!.
I could never figure out when you where suposed to use
them. - Well I'll be darned.
Arthur
Harry Curzon
Beavis wrote:
>
> In article <199804072312...@ladder03.news.aol.com>, AJDalton7
> <ajda...@aol.com> writes
> >>But Arthur, if it's upside down AND coming back towards you all's well
> >>again:-)
> >
> >Not if you'r standing on your Head !!
> >
> > Arthur
>
>
> Beav
And we're all looking at it from a northern hemisphere viewpoint. Is it
all reversed again in Australia? What if you are one of the military
pilots of the future flying your r/c F-35, standing in a field in the
good ol' US of A watching the satellite camera view of your plane just
as it crosses south of the equator on its way to bring "freedom" to some
tiny south american dictatorship? Will the rudder suddenly reverse from
your viewpoint since the plane now appears inverted to you?
Harry
Harry Curzon
AJDalton7 wrote:
>
> >Bugger!! I forgot about that :-)
> >
> >Beav
>
> That's what thoes little servo reverse switches must be for!!!.
> I could never figure out when you where suposed to use
> them. - Well I'll be darned.
> Arthur
Yeah, they should not hide them behind those silly panels, let's have
them out front on big toggle switches where we can easily get at them!
Just think, roll your aileron model inverted, flick 2 switches for elev
and rudder reversing and bingo. It will fly as normal. I'm going to
write to Futaba about this!
Harry
AJDalton7
Well that's your point of view !!!
Arthur
Beavis
In article <199804100114...@ladder03.news.aol.com>, AJDalton7
<ajda...@aol.com> writes
>>Bugger!! I forgot about that :-)
>>
>>Beav
>
>Beav,
>That's what thoes little servo reverse switches must be for!!!.
>I could never figure out when you where suposed to use
>them. - Well I'll be darned.
> Arthur
Servo reversing switches??? I thought you had to nail the servo in
upside down if it went the wrong way. You must be one of those chaps
that's bought a fancy radio:-) God how I hate you for having all that
spare money.
Beavis
In article <352DCE...@cableinet.co.uk>, Harry Curzon
<h.cu...@cableinet.co.uk> writes
>AJDalton7 wrote:
>>
>> >Bugger!! I forgot about that :-)
>> >
>> >Beav
>>
>> Beav,
>> That's what thoes little servo reverse switches must be for!!!.
>> I could never figure out when you where suposed to use
>> them. - Well I'll be darned.
>> Arthur
>
>them out front on big toggle switches where we can easily get at them!
>Just think, roll your aileron model inverted, flick 2 switches for elev
>and rudder reversing and bingo. It will fly as normal. I'm going to
>write to Futaba about this!
>
>Harry
I think you'd be wasting your time Harry. Futaba'd probably think it was
a daft idea and then decide to start making radio's with computer chips
inside 'em and drop a book into the packaging showing us how to switch
the thing ON.
Anyway I can't see it happening myself, before you know it people would
be saying "Look, I can fly upside down WITHOUT using the switches"
just to show off :-) I think they'd STILL be using the swtiches though,
but they'd be a different ones, hidden somewhere behind a panel.