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davidjoyce(at)doctors.org
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 Posted: Sat Jun 16, 2012 1:47 pm Post subject: Avoiding ground loops |
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Have been doing a bit of thinking about how I could
possibly have done a ground loop at my advanced age, and
having inadvertently shared my loop with you while
sleepily assuming I was replying to Tim personally, I
thought I might share my conclusions with you. It seems to
me that like meeting a large bird nose/beak on or
ditching, ground looping is something you don't get
taught, but something where a bit of prior nought would
definitely be an asset! So here's my thoughts:
Having turned 90 degrees left off the 09 runway,
I was taxying at a brisk pace up the 36 runway with a
brisk (said on landing to be 10kts, but on measuring
immediately after the loop 10, gusting 18kts) coming from
R rear quarter. After a momentary look at an instrument, I
found myself swinging right. Full left rudder didn't stop
the swing, and my reflex was to brake, as this generally
of course helps turning manoeuvres in a mono. The turn
continued and the plane went gently forwards and left with
the ground touching the left wingtip and the prop. The
stick was hard back all the time, because this is also
ingrained in mono pilots to increase the authority of the
tail wheel.
With the amazing wisdom of hindsight, I
strongly suspect that had I not braked the plane would not
have gone A over T onto its prop, although it might have
still touched the left wingtip. Slowing down and cutting
the throttle also of course reduced airflow over the tail
plane reducing the tail down forces, and removed the left
turning effect of prop wash acting on the port side of the
fin. So if I ever find myself threatened with a difficult
to control tendency to turn sharply into wind, I hope I
shall remember to accelerate rather than brake. An
excursion on to the grass would have been a minor matter
compared with a set of new blades + engine check. Glad to
hear anyone else's experience or thoughts. Regards, David
Joyce! G-XSDJ
PS Now when confronted with a large bird looking as though
it is coming through the screen I reckon the smart move is
to pull up, as birds are likely to dive in a panic
situation as their only means of rapidly gaining speed to
avoid a threat, but when it first happened I hesitated a
bit before turning right, wondering whether the bird knew
the rules of the air! Ditching thoughts in due course.
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kheindl(at)msn.com
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| Posted: Sat Jun 16, 2012 2:57 pm Post subject: Avoiding ground loops |
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Hi David,
From what you are saying, you had the stick at full aft? With a tailwind this would have lifted your tail. Had you pushed the stick full forward you might have prevented the mishap.
Karl
| Quote: | From: davidjoyce(at)doctors.org.uk
Subject: Avoiding ground loops
To: europa-list(at)matronics.com
Date: Sat, 16 Jun 2012 22:46:03 +0100
--> Europa-List message posted by: "David Joyce" <davidjoyce(at)doctors.org.uk>
Have been doing a bit of thinking about how I could
possibly have done a ground loop at my advanced age, and
having inadvertently shared my loop with you while
sleepily assuming I was replying to Tim personally, I
thought I might share my conclusions with you. It seems to
me that like meeting a large bird nose/beak on or
ditching, ground looping is something you don't get
taught, but something where a bit of prior nought would
definitely be an asset! So here's my thoughts:
Having turned 90 degrees left off the 09 runway,
I was taxying at a brisk pace up the 36 runway with a
brisk (said on landing to be 10kts, but on measuring
immediately after the loop 10, gusting 18kts) coming from
R rear quarter. After a momentary look at an instrument, I
found myself swinging right. Full left rudder didn't stop
the swing, and my reflex was to brake, as this generally
of course helps turning manoeuvres in a mono. The turn
continued and the plane went gently forwards and left with
the ground touching the left wingtip and the prop. The
stick was hard back all the time, because this is also
ingrained in mono pilots to increase the authority of the
tail wheel.
With the amazing wisdom of hindsight, I
strongly suspect that had I not braked the plane would not
have gone A over T onto its prop, although it might have
still touched the left wingtip. Slowing down and cutting
the throttle also of course reduced airflow over the tail
plane reducing the tail down forces, and removed the left
turning effect of prop wash acting on the port side of the
fin. So if I ever find myself threatened with a difficult
to control tendency to turn sharply into wind, I hope I
shall remember to accelerate rather than brake. An
excursion on to the grass would have been a minor matter
compared with a set of new blades + engine check. Glad to
hear anyone else's experience or thoughts. Regards, David
Joyce! G-XSDJ
PS Now when confronted with a large bird looking as though
it is coming through the screen I reckon the smart move is
to pull up, as birds are likely to dive in a panic
situation as their only means of rapidly gaining speed to
avoid a threat, but when it first happened I hesitated a
bit before turning right, wondering whether the bird knew
the rules of the air! Ditch======================
>=====================
|
[quote][b]
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klinefelter.kevin(at)gmai
Guest
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| Posted: Sat Jun 16, 2012 3:07 pm Post subject: Avoiding ground loops |
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David,
I too have had a similar excursion and done what you did with much the same pain in the wallet. I believe you are correct in the hindsight that thou shalt not touch thy brake, which is I believe incredibly difficult to do once your outrigger fails and the noise of the wingtip grinding off on the pavement fills your ears.
My incident occurred following a pretty benign skip/bounce. I had been flying for quite some time without replacing the roll pin that prevents the tail wheel from turning round backwards. On the bounce, the tail wheel did the seemingly impossible by turning completely backwards, which locks due to the springs in an over center configuration, resulting in a loss of directional control.I know it was in that configuration as I touched down after the bounce because the left rudder pedal went to the floor with no resistance as the nose swung right. I had thought the little roll pin unimportant. The cracks in the pavement probably contributed to the tail wheel castering round on touchdown.
Don't fly without the stupid roll pin and and don't touch the brake. I'm not sure I can keep my hand off the brake let alone move it to the throttle!
Kevin
On Jun 16, 2012, at 2:46 PM, "David Joyce" <davidjoyce(at)doctors.org.uk> wrote:
| Quote: |
Have been doing a bit of thinking about how I could possibly have done a ground loop at my advanced age, and having inadvertently shared my loop with you while sleepily assuming I was replying to Tim personally, I thought I might share my conclusions with you. It seems to me that like meeting a large bird nose/beak on or ditching, ground looping is something you don't get taught, but something where a bit of prior nought would definitely be an asset! So here's my thoughts:
Having turned 90 degrees left off the 09 runway, I was taxying at a brisk pace up the 36 runway with a brisk (said on landing to be 10kts, but on measuring immediately after the loop 10, gusting 18kts) coming from R rear quarter. After a momentary look at an instrument, I found myself swinging right. Full left rudder didn't stop the swing, and my reflex was to brake, as this generally of course helps turning manoeuvres in a mono. The turn continued and the plane went gently forwards and left with the ground touching the left wingtip and the prop. The stick was hard back all the time, because this is also ingrained in mono pilots to increase the authority of the tail wheel.
With the amazing wisdom of hindsight, I strongly suspect that had I not braked the plane would not have gone A over T onto its prop, although it might have still touched the left wingtip. Slowing down and cutting the throttle also of course reduced airflow over the tail plane reducing the tail down forces, and removed the left turning effect of prop wash acting on the port side of the fin. So if I ever find myself threatened with a difficult to control tendency to turn sharply into wind, I hope I shall remember to accelerate rather than brake. An excursion on to the grass would have been a minor matter compared with a set of new blades + engine check. Glad to hear anyone else's experience or thoughts. Regards, David Joyce! G-XSDJ
PS Now when confronted with a large bird looking as though it is coming through the screen I reckon the smart move is to pull up, as birds are likely to dive in a panic situation as their only means of rapidly gaining speed to avoid a threat, but when it first happened I hesitated a bit before turning right, wondering whether the bird knew the rules of the air! Ditching thoughts in due course.
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rparigoris
Joined: 24 Nov 2009
Posts: 805
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| Posted: Sat Jun 16, 2012 3:49 pm Post subject: Re: Avoiding ground loops |
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Hi David
Thanks for sharing your experience.
I am close to a zero time Mono pilot (perhaps 5 minutes of taxi time on a demo) so I am far from one with first hand experience. , but did own a Cessna 170 taildragger for 19 years and have flown various taildraggers along the way.
My perception of the Europa was that it has an extremely powerful tailwheel steering, just need to make sure you keep pressure on the tailwheel and "KEEP IT STRAIGHT" because it does not have differential braking to save you if you let things get out of shape (pointer target on windscreen not only helps learn how to keep it straight, but can aid in landing additude). Whenever I fly a unconventional aeroplane (nosedragger), I always get strange looks and am questioned why am I working so hard to taxi a fool aeroplane on the ground. When and if the skygods decide to deal me conditions I would rather not be out in, this technique can pay a handsome reward even in an unconventional aeroplane.
Other than that the only negative I had about ground handling of the XS mono is the poor turning radius (XS stock bell-crank), but that is only a minor inconvenience that I have no problem dealing with.
Reading with great interest about your entry into the club of (those who have), if you don't mind I would like to do a little armchair flying about 5 concepts I have about ground handling of the mono. Please comment (comments from and put me in my place if I am off base and set me straight.
1) Prior to purchasing my XS Monowheel, I read and spoke with folks about nosing over on a mono and touching a wingtip and hurting the prop when you attempt to use the brake if you are in any sort of turn at all (including losing an outrigger). I made a representative model with scale placement of the main wheel, tailwheel and outriggers. It is quite obvious that if you are going other than straight, any turning force moves the canter of gravity balance on the ground to a more nose heavy configuration, the reason being is the outriggers are aft of the main wheel and when side loads begin to load an outrigger, the net result is moving your pivot point back. Being a long time mono pilot, this should be second nature to know not to hit the brake if in a turn? If you enter a serious swerve, opposite rudder, kill power if you have mindset and take the consequences without hitting the brake, unless you manage to get it going straight. This would be my plan, and I would practice in my mind that if I lost control, this is what I would do. In other words practice making my reflex to not hit the brake in the event of a swerve because of the well known consequences. Is this the wrong thing to practice?
2) I think everyone is in agreement that you want to keep weight on the tailwheel so you have effective steering. When you taxi downwind, you don't need very much power. When you taxi downwind the airflow will be going over the stabilator in the reverse direction to normal flight if your taxi speed is less than the wind speed. If that is the case then you do not want your stabilator full aft because that reverse airflow will in fact reduce the pressure on the tailwheel. On many tailwheel aeroplanes you would want full forward stick to get maximum downpressure on the tailwheel with reverse airflow over the stabilator. Several high time mono pilots say although this is true, if you add significant power you could reverse the flow, so they settle for perhaps neutral stabilator just in case you add a lot of power and forget to pull stick full aft. What's your thoughts on this practice?
3) I was planning on putting my bird in various amounts of wind with a direct tailwind and also a quartering tailwind and measure tailwheel force with no power, taxi power, and a larger amount of power to try and figure out optimal technique of keeping the tailwheel planted. Did you, or anyone test this? What were findings?
I was going to do the same test with a quartering wind and measure the effect of full into the wind and full downwind ailerons. Motor off, stiff quartering tailwind, main on a greaseplate and tailwheel on a skateboard to allow EZ weathervaning.
4) Again we all know we are at a disadvantage with a mono because we don't have differential braking. When getting nailed with a right quartering tailwind, the nose will want to swing right. Adding a little left brake is a desirable thing. Thus keep the stick full left aileron so reverse air will push the right wing harder downwind than the left wing which should be the equivalent to a token amount of left brake. This is standard for many taildraggers. Is there a reason it should not be standard practice on a mono? It also puts a token amount of downforce on the upwind wing.
5) I am at a loss when I look at the cable tension for monowheel steering. I may be missing something, but with the standard XS set up, why would anyone ever consider having anything else than precompressed springs that should allow for the most precise control? It seems anything other than precompressed springs would be like driving a car with a worn rack and pinon steering mechanism with a lot of slop between engagement of left and right movement of wheels.
Is there something I am missing?
Again I have no practical experience and wish to learn from others on best practices and techniques.
Sincerely
Ron Parigoris
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davidjoyce(at)doctors.org
Guest
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| Posted: Sat Jun 16, 2012 11:46 pm Post subject: Avoiding ground loops |
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Ron, I commend your approach of analysing problems before
they get you! I should probably say that I had not given
you the whole background. On our rececent Northern Lights
trip (which weathr routed round the Med) I had a problem
with the contact breaker for instruments popping, and had
isolated the guilty wire so that I at least had engine
instruments and fuel gauge. When landing on the day in
question on hearing the stall Warner going It occurred to
me to wonder whether that was on the same CB, so after
turning off the active runway I taxied fast enough
(probably 20+kts) to get the stall Warner squeaking and
pulled the CB. It was on looking back up from pulling the
CB that I found myself swerving to the right (you might
say 'serves me right at this point!) So addressing your
points:
1) Fine except killing power will reduce the down force on
the tail plane.
2) I was taxying faster than what I had been told was the
total tail wind so not a situation to shove stick forward,
and in addition I have measured airflow past back of door
at 40kts when on ground stationary at fast idle, so my
feeling is that the stick needs full back unless you are
in a gale going very slowly down wind
3) All my 950 hrs in the mono tell me to keep the stick
hard back all the time other than when gaining speed as
you take off.
4)As in a glider it becomes natural on the ground to use
the ailerons to stop the plane leaning, and this may meanR
stick to deal with R lean in following wind
5) I have the Singleton tail wheel mod (much recommended)
so can't help on those sort of problems
My comment on braking helping turning needs
enlarging. It is possible to almost spin on the main wheel
by judicious use of brake and power, but this is partly a
question of using the plane's inertia to make the C of G
which is behind the wheel, carry on round it. So braking
only encourages a turn to continue - it counteracts
efforts to stop a turn. So the clear message for me is if
started on an uncontrollable turn DO NOT brake and
consider putting in more power, unless of course that
would send you into something hard or expensive!
Regards, David Joyce, G-XSDJ
On Sat, 16 Jun 2012 16:49:55 -0700
"rparigoris" <rparigor(at)suffolk.lib.ny.us> wrote:
| Quote: |
<rparigor(at)suffolk.lib.ny.us>
Hi David
Thanks for sharing your experience.
I am close to a zero time Mono pilot (perhaps 5 minutes
of taxi time on a demo) so I am far from one with first
hand experience. , but did own a Cessna 170 taildragger
for 19 years and have flown various taildraggers along
the way.
My perception of the Europa was that it has an extremely
powerful tailwheel steering, just need to make sure you
keep pressure on the tailwheel and "KEEP IT STRAIGHT"
because it does not have differential braking to save you
if you let things get out of shape (pointer target on
windscreen not only helps learn how to keep it straight,
but can aid in landing additude). Whenever I fly a
unconventional aeroplane (nosedragger), I always get
strange looks and am questioned why am I working so hard
to taxi a fool aeroplane on the ground. When and if the
skygods decide to deal me conditions I would rather not
be out in, this technique can pay a handsome reward even
in an unconventional aeroplane.
Other than that the only negative I had about ground
handling of the XS mono is the poor turning radius (XS
stock bell-crank), but that is only a minor inconvenience
that I have no problem dealing with.
Reading with great interest about your entry into the
club of (those who have), if you don't mind I would like
to do a little armchair flying about 5 concepts I have
about ground handling of the mono. Please comment
(comments from and put me in my place if I am off base
and set me straight.
1) Prior to purchasing my XS Monowheel, I read and spoke
with folks about nosing over on a mono and touching a
wingtip and hurting the prop when you attempt to use the
brake if you are in any sort of turn at all (including
losing an outrigger). I made a representative model with
scale placement of the main wheel, tailwheel and
outriggers. It is quite obvious that if you are going
other than straight, any turning force moves the canter
of gravity balance on the ground to a more nose heavy
configuration, the reason being is the outriggers are aft
of the main wheel and when side loads begin to load an
outrigger, the net result is moving your pivot point
back. Being a long time mono pilot, this should be second
nature to know not to hit the brake if in a turn? If you
enter a serious swerve, opposite rudder, kill power if
you have mindset and take the consequences without
hitting the brake, unless you manage to get it going
straight. This would be my plan, and I would practice i!
n my mind that if I lost control, this is what I would
do. In other words practice making my reflex to not hit
the brake in the event of a swerve because of the well
known consequences. Is this the wrong thing to practice?
2) I think everyone is in agreement that you want to
keep weight on the tailwheel so you have effective
steering. When you taxi downwind, you don't need very
much power. When you taxi downwind the airflow will be
going over the stabilator in the reverse direction to
normal flight if your taxi speed is less than the wind
speed. If that is the case then you do not want your
stabilator full aft because that reverse airflow will in
fact reduce the pressure on the tailwheel. On many
tailwheel aeroplanes you would want full forward stick to
get maximum downpressure on the tailwheel with reverse
airflow over the stabilator. Several high time mono
pilots say although this is true, if you add significant
power you could reverse the flow, so they settle for
perhaps neutral stabilator just in case you add a lot of
power and forget to pull stick full aft. What's your
thoughts on this practice?
3) I was planning on putting my bird in various amounts
of wind with a direct tailwind and also a quartering
tailwind and measure tailwheel force with no power, taxi
power, and a larger amount of power to try and figure out
optimal technique of keeping the tailwheel planted. Did
you, or anyone test this? What were findings?
I was going to do the same test with a quartering wind
and measure the effect of full into the wind and full
downwind ailerons. Motor off, stiff quartering tailwind,
main on a greaseplate and tailwheel on a skateboard to
allow EZ weathervaning.
4) Again we all know we are at a disadvantage with a
mono because we don't have differential braking. When
getting nailed with a right quartering tailwind, the nose
will want to swing right. Adding a little left brake is a
desirable thing. Thus keep the stick full left aileron so
reverse air will push the right wing harder downwind than
the left wing which should be the equivalent to a token
amount of left brake. This is standard for many
taildraggers. Is there a reason it should not be standard
practice on a mono? It also puts a token amount of
downforce on the upwind wing.
5) I am at a loss when I look at the cable tension for
monowheel steering. I may be missing something, but with
the standard XS set up, why would anyone ever consider
having anything else than precompressed springs that
should allow for the most precise control? It seems
anything other than precompressed springs would be like
driving a car with a worn rack and pinon steering
mechanism with a lot of slop between engagement of left
and right movement of wheels.
Is there something I am missing?
Again I have no practical experience and wish to learn
from others on best practices and techniques.
Sincerely
Ron Parigoris
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h&jeuropa
Joined: 07 Nov 2006
Posts: 649
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| Posted: Sun Jun 17, 2012 3:06 am Post subject: Re: Avoiding ground loops |
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A quick note on your PS regarding birds. Many years ago, I was transitioning to a Mooney, on final, and ducks appeared, flying across my path from stbd & directly for the windscreen (I could see their eyes!). I announced to tower I was going around & pulled up. After, the instructor said that was the right thing to do on a bird encounter, not because of where the birds might fly, but because if they hit the plane, it is better to have the impact on a structure like the belly than the windscreen.
Heather
N241BW
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f.kyle(at)sympatico.ca
Guest
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| Posted: Sun Jun 17, 2012 1:24 pm Post subject: Avoiding ground Loops |
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Fellow mono birds:
I followed the discussion with interest and was intrigued to see the
by-play regarding various winds while taxying..
I seem to remember (from Harvard days - our initial machine), that
much emphasis was put on the proper positioning of the stick.....
I seem to have several pokes of the rear seat stick to the back of my empty
head that - the stick is opposite the known wind when same is over 10
knots.* Now the poor old HVD is much heavier so suspect the stick is more
sensitive at lower Europa winds.
PLUS the vert stab/rudder is much more sensitive than the HVD model
AND the winds were carefully measured and divulged at a training station.
FWIW
Ferg
C-FFGG 914 mono CSprop
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