Re: I have problem. I correct the aileron the wrong way at takeoff

[Derek Copeland[_2_]]

I had one of my students (also in his 40s or maybe early 50s) do something
similar during the ground run of a winch launch last year, which is
potentially catastrophic, and could have easily caused a big cartwheel
type accident.

On a rather windy and gusty evening the left wing started to drop and he
compounded this this by moving the stick hard left and back! Before I had
a chance to take over the glider was already in the air in a steep
climbing attitude, with the left wing hard on the ground. Somehow I
managed to rescue this situation, probably helped by the fact that our
airfield has relatively short and smooth grass, and a switched on winch
driver. This incident definitely used up one of my nine lives!

This particular student was about halfway to solo, and had not done
anything particularly strange before. When debriefed after the flight he
was unable to explain why he did what he did.

The easiest way of thinking about the ailerons is that they roll the
glider in the direction the stick is pushed. Most people find this fairly
instinctive: It's usually the rudder they find difficult. Certainly when
I learnt to fly, I thought it ought be connected the other way round, so
it was more like a bike. But that's the way the aviation pioneers did it,
so we are stuck with it as a convention and you have to learn to live with
it. Most people do, although I occasionally get students who push the
wrong pedal when entering a turn!

Derek C

At 07:22 19 January 2009, Jack wrote:
>Hi all,
>I have a problem with correcting the ailerons the wrong way at takeoff,
>obviously that is a very serious problem and I would like some feedback
if
>
>possible.
>
>First here is a bit of background.
>I am a new glider pilot (44yo), I only have about 40 flights.
>I have learnt in 2 different clubs one large club where I never had the
>same
>instructor for more than 2 flights and a smaller club wher I spent a
week
>to
>get solo with the same instructor.
>I started flying gliders a few month ago and had a reasonably fast
>progression, at 32 flights I went solo (in the small club) and had a
>couple
>of solos that went fine.
>Then back to the larger club I had a few more flights with new
>instructors,
>flights weren't perfect but all safe and without incidents.
>
>Then Yesterday as I was taking off in calm conditions I touched the
ground
>
>with a wing, the instructor had to intervene, it was the 1st time an
>instructor took the commands in a critical situation.
>He just put the glider flat and gave me control back 5 seconds later. The

>rest of the flight went fine, I had difficult conditions in circuit where

>another glider was joing at the same time and height as me but I
handeled
>it
>well.
>
>Back to the incident the instructor does not know what happened, I
suspect
>
>he did not have the hands on the commands but unfortunatley I think I
>know,
>as the left wing dropped I think I gave stick to the left instead of
>right.
>
>While at the small club at around flight 20 or 25 I had a similar
>situation,
>left wing dropped at takeoff, I gave a bit of left, the instructor
shoted
>to
>me to give right and apparently I gave some more left and then right. The

>instructor very worried about it and told me she had never seen someone
>with
>that problem. From my side I didn't remembre what I did.
>
>It is not that I had all easy take offs where I had nothing to do, I have

>done a few in 10+kts cross wind take off and landings and didn't have
>problems.
>
>Then a possible 3rd incident, landing after touch down on the ground
roll
>I
>suspect I have used the wrong aileron control and the caught up and
>compensated the right way.
>
>
>Where I would like feedback is if someone has seen such or similar
>behaviour, what were the cures, does it go away ?
>
>I have an idea of what may cause that problem but I dont want to expose
it
>
>yet as it may inhibit the responses based on another theory.
>
>Thanks
>
>
>
>

[Martin Gregorie[_4_]]

On Mon, 19 Jan 2009 23:30:03 +0000, Derek Copeland wrote:

> The easiest way of thinking about the ailerons is that they roll the
> glider in the direction the stick is pushed. Most people find this
> fairly instinctive: It's usually the rudder they find difficult.
>
That certainly describes me, though I'd done just enough casual GA flying
(i.e. in friend's planes) to have overcome rudder direction problems
before I started learning to fly gliders. I've never had stick problems,
probably because I realized very early on that you move the top of the
stick to 'push' the glider to the attitude you want and its the same in
both axes.

I can see one advantage to connecting the pedals the way they are. Your
knee is never in the way of the stick when starting or leaving a turn. At
a guess a conventionally placed stick would be unusable if the pedals
were connected to work like a bike's handlebars because there would
always be a knee in the way.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Jack[_11_]]

Thanks all for the big feedback, lots of excellent ideas.

Some points I just want to clarify, this only happened at take off and
possibly at landing, never in flight.
I usually do not have problems doing the compensations neither diassotiating
the rudder and ailerons controls at takeoff, outside of the 2 incidents my
takeoffs (about 30) are consistently good but due to the possible
consequences, it really worries me.

What I think the cause is, is that a wing drop, I compensate the right way,
I do not see the expected effect, I subconsiously doubt about my actions and
move the other way.
I try to not really think my actions mostly it is conditioned reflexes, that
may also be why I struggle to remembre exactly what I did.

Training on the ground seems an excellent idea.

Simulator, I do have Condor and rudder pedals, the take off in Condor is
rather different than in real but worth for me to train on.

Tunel vision, that certainly agravates the problem, early on I was so
focussed that I was unable to hear the instructor talk to me in high stress
situations. I dont stress that much anymore (in fact I am mostly quite
relaxed) and I am able to hear and talk at anytime now. Wether it is about
the flight or the footy game.


Regarding the direction of the rudder vs left/right pedal, I believe the
people that use it the wrong way have what is called "Billy Cart Syndrom"
probably due to the fact that in a Billy Cart you push the front axle on the
right foot to go left.
Luckyly enough I do not have that problem.


While waiting for a windy day I'll train on Condor :)

Thanks all

[Bruce Hoult]

On Jan 20, 12:30*pm, Derek Copeland > wrote:
> The easiest way of thinking about the ailerons is that they roll the
> glider in the direction the stick is pushed. Most people find this fairly
> instinctive: It's usually the rudder they find difficult. Certainly when
> I learnt to fly, I thought it ought be connected the other way round, so
> it was more like a bike.

Um .. er .. what?

Aircraft pedals work in the SAME sense as bike/motorcycle handlebars
-- you push on the left one to go left then push on the right one to
roll back upright again (or to the right).

And in both cases you want to be neutral or push a little bit of
opposite (top) while steady in a turn.

[Derek Copeland[_2_]]

At 08:32 20 January 2009, Bruce Hoult wrote:
>On Jan 20, 12:30=A0pm, Derek Copeland wrote:
>> The easiest way of thinking about the ailerons is that they roll the
>> glider in the direction the stick is pushed. Most people find this
>fairly
>> instinctive: It's usually the rudder they find difficult. Certainly
when
>> I learnt to fly, I thought it ought be connected the other way round,
so
>> it was more like a bike.
>
>Um .. er .. what?
>
>Aircraft pedals work in the SAME sense as bike/motorcycle handlebars
>-- you push on the left one to go left then push on the right one to
>roll back upright again (or to the right).
>
>And in both cases you want to be neutral or push a little bit of
>opposite (top) while steady in a turn.
>
So try making a slow turn to the right on a bike while holding the
handlebars to the left! Don't blame me when you fall off though!

Derek C

[vaughn]

"Derek Copeland" > wrote in message
...
> So try making a slow turn to the right on a bike while holding the
> handlebars to the left! Don't blame me when you fall off though!

This is getting rather far afield and has little or nothing to do with
flying, but turning a motorcycle is not as simple a process as you may
think. Those who have any time on heavy motorcycles instinctivly apply
pressure to the handlebars OPPOSITE to the direction of the intended turn.
Because of the gyroscoptic precession of that big, heavy front wheel, this
tilts the bike, and it is the tilt that does the actual turning. To roll
the bike back vertical and stop the turn, you apply handlebar pressure INTO
the turn.

Of course, when you are moving too slowly for that front wheel to act as a
gyro, the rules are reversed.

It is one of those things that is harder to explain than it is to do; it is
so instinctive that nobody really needs to teach you.

Vaughn (About 100,000 miles on the same BMW)

[bildan]

On Jan 20, 6:43*am, "vaughn" >
wrote:
> "Derek Copeland" > wrote in message
>
> ...
>
> > So try making a slow turn to the right on a bike while holding the
> > handlebars to the left! Don't blame me when you fall off though!
>
> * *This is getting rather far afield and has little or nothing to do with
> flying, but turning a motorcycle is not as simple a process as you may
> think. *Those who have any time on heavy motorcycles instinctivly apply
> pressure to the handlebars OPPOSITE to the direction of the intended turn..
> Because of the gyroscoptic precession of that big, heavy front wheel, this
> tilts the bike, and it is the tilt that does the actual turning. *To roll
> the bike back vertical and stop the turn, you apply handlebar pressure INTO
> the turn.
>
> Of course, when you are moving too slowly for that front wheel to act as a
> gyro, the rules are reversed.
>
> It is one of those things that is harder to explain than it is to do; it is
> so instinctive that nobody really needs to teach you.
>
> Vaughn *(About 100,000 miles on the same BMW)


Yep, It's best not to take the motorcycle analogy too far. It used to
be fun to point out the "reverse steering" concept and then watch as
tatooed bikers sat on the curb next to their bikes with vacant looks
on their faces - once they actually thought about it, they couldn't
ride anymore. Now, gyroscopic reverse steering is taught in
motorcycle riding classes.

Back to gliders.

I notice that there is some serious misunderstandings about how to
manage a takeoff roll. If you watch a series of takeoffs, you'll see
that most of the pilots are fighting their wing runners.

A useful rethink is to consider that the wing runners job is to
BALANCE the glider laterally not to just "level the wings". That way
the wing won't instantly fall when it's released. The runner should
find the 'zero force' point where the glider is perfectly balanced
into any crosswind and run the wing at that angle.

The pilot should let the wing runner do his job by holding the
ailerons exactly neutral until it's clear the runner is no longer
holding the wing - usually at "three Mississippi" and only then take
over roll control.

Brief your wing runner and then try it on your next takeoff. You'll
both find it much less stressful.

Bill Daniels

[brtlmj]

> A useful rethink is to consider that the wing runners job is to
> BALANCE the glider laterally not to just "level the wings". That way
> the wing won't instantly fall when it's released. The runner should
> find the 'zero force' point where the glider is perfectly balanced
> into any crosswind and run the wing at that angle.
>
> The pilot should let the wing runner do his job by holding the
> ailerons exactly neutral until it's clear the runner is no longer
> holding the wing

In mu humble opinion:
- The wing runner should make sure that the pilot knows what his
glider wants to do. For example, if the wing wants to fall - lower it,
just enough for the pilot to notice. His job is much better described
as "do not let the wing touch the ground" than "level the wings".
- The pilot should use correct control inputs to compensate for any
bank or yaw from the very beginning of the takeoff roll.

B.

[Bruce Hoult]

On Jan 21, 2:43*am, "vaughn" >
wrote:
> "Derek Copeland" > wrote in message
>
> ...
>
> > So try making a slow turn to the right on a bike while holding the
> > handlebars to the left! Don't blame me when you fall off though!
>
> * *This is getting rather far afield and has little or nothing to do with
> flying, but turning a motorcycle is not as simple a process as you may
> think. *Those who have any time on heavy motorcycles instinctivly apply
> pressure to the handlebars OPPOSITE to the direction of the intended turn..
> Because of the gyroscoptic precession of that big, heavy front wheel, this
> tilts the bike, and it is the tilt that does the actual turning. *To roll
> the bike back vertical and stop the turn, you apply handlebar pressure INTO
> the turn.

Yes, except it's nothing to do with being heavy or precession. It
works just the same on bicycles or even on things with no rotating
wheels at all such as those snow scooter things with handlebars
attached to a ski up front.

It's all about moving one or both wheels sideways out from under the
center of gravity. The CoG is trucking along in a straight line so to
establish bank for a left turn you shuffle the wheels over to the
right of the track the CofG is taking.

The gyroscopic precession does help too, but it's not essential.


> Of course, when you are moving too slowly for that front wheel to act as a
> gyro, the rules are reversed.

No, it's the same, just more subtle. At low speeds you need less bank
angle for a given turn radius (just as in a glider), so the initial
"roll in with opposite steering" phase is much shorter. Once
established with the bank angle you want, you then need much a much
larger out of turn control input (i.e. turning the handlebars left in
a left turn) to prevent the bank angle from increasing further.

> Vaughn *(About 100,000 miles on the same BMW)

Bruce
(117,000 km on his current 1995 BMW R1100RT,
130,000 km on previous 1986 K100RT,
30,000 km on previous 1982 R80RT (gateway drug),
~100,000 km on prior assorted Hondas (CBX550, CBX400, XR600, XR250,
XL350)

[Ian]

On 20 Jan, 09:45, Derek Copeland > wrote:

> So try making a slow turn to the right on a bike while holding the
> handlebars to the left! Don't blame me when you fall off though!

He'r right, you know. While turning to the right, a cyclist will have
the handlebars turned to the left, and vice versa. That's when the
thing is being ridden dynamically, so it rolls into turns. If it's
kept upright the handlebars work the other way round. This causes real
issues with sidecars: as soon as the sidecar wheel leaves the ground,
the effect of the steering reverses...

Ian

[Ian]

On 20 Jan, 13:43, "vaughn" > wrote:

> * *This is getting rather far afield and has little or nothing to do with
> flying, but turning a motorcycle is not as simple a process as you may
> think. *Those who have any time on heavy motorcycles instinctivly apply
> pressure to the handlebars OPPOSITE to the direction of the intended turn..
> Because of the gyroscoptic precession of that big, heavy front wheel, this
> tilts the bike, and it is the tilt that does the actual turning.

Humm. Bike going forward. Rotation vector of front wheel goes right to
left (using right-handed axis system). Push left handlebar forwards.
Front of rotation vector moves forwards. Precession vector is change
in rotation vector: front to back. Which is a roll to the right.

In other words, the affect of precession would roll in the direction
of steer.

Ian

[Ian]

On 20 Jan, 14:39, bildan > wrote:

> A useful rethink is to consider that the wing runners job is to
> BALANCE the glider laterally not to just "level the wings". *That way
> the wing won't instantly fall when it's released. * The runner should
> find the 'zero force' point where the glider is perfectly balanced
> into any crosswind and run the wing at that angle.
>
> The pilot should let the wing runner do his job by holding the
> ailerons exactly neutral until it's clear the runner is no longer
> holding the wing - usually at "three Mississippi" and only then take
> over roll control.

I think these two points are in contradiction. If the wing would fall
when released unless the pilot did something, it wasn't balanced.

As a wing runner I respond to any wing tip forces. Pre-take off, if my
tip is pushing down, I will let it go down, to the ground of
necessary, till the pilot uses aileron to cancel the forces, at which
point I will keep the wings (a) level and (b) balanced.

I expect the same when I'm the pilot.

This is particularly important when winch launching, as the pilot will
experience any unbalanced roll forces within a second or three of the
all out, and have very little time to correct.

Ian