BIG
EARS IN FORUMS
Here’s a compilation
of some of the messages appeared in BigAir and Europg Forums about Big Ears
(we have edited some of them). The message that originated the debate is the
one below, but its author "dissapeared" once the polemic was still
hot, and the case was never proved to have happened, nobody heard of it in
the US... A hoax? We think so too. The discussion is interesting, though.
Date: November 11, 2002
Author: Mark Stewart
Subject: Big Ears are dangerous
Two weeks ago a
friend of mine was flying one of the newest DHV 1-2 wings, he had several years
of experience, he only took the wing to test fly it. Conditions were strong
that day but flyable. He pulled the big ears in to loose some altitude, and
when he got close to the ground he tried to pump them out one at a time. He
pumped one side (too aggressively maybe) and the wing went into a negative
spin, he had experience with this kind of situations, so he raised his hand
instantly, but the wing surged a long way and he crashed face down. He died 20
minutes later from abdominal injuries.
I'm writing this to
tell you, please watch out when you perform big ears; pump once then wait until
the wing stabilizes then pump again.
We under estimate
sometimes the seriousness of the manoeuvres we do, please watch out all of you
because accidents do happen and the proof my friend is dead, Daniel is dead.
Date: November 11, 2002 05:17 PM
Author: mike dufty
Subject: Vibe Manual
The vibe manual
http://www.ozone-gliders.com/vibe_manual.htm#descent has the following to say about big ears:
Big Ears
Folding in the
wingtips of the Vibe increases its sink rate. This is useful for staying out of
cloud or descending quickly. To pull big ears on the Vibe take the outermost
A-line and pull it down until the tips of the wing fold under. OZONE gliders
are fitted with split A-risers to make this procedure easy.
Once the big ears
are in you can further increase the sink rate by pushing on the accelerator
bar.
NEVER try to pull
the Big Ears in with the speed bar on. This can lead to a major asymmetric
deflation.
Remember that once
the Big Ears are in, you have less wing area supporting you so your stall speed
will have increased.
Do not use the brakes
other than for re-inflation. For directional control while using the Big Ears,
you should use weight shift.
To reopen the wing
tips, release the outer A line, normally the tips will re-inflate
automatically. You can help the process by leaning away from the side you want
to re-inflate and gently pumping the brakes. Do this one side at a time to
minimise the chance of inducing a stall.
WARNING: Do not use
Big Ears near the ground.
Date: November 14, 2002 03:39 PM
Author: Roger Wolff
Subject: 1-2 rating, pumping ears....
I also thought that
asymmetrics would have to "solve" themselves, for a 1-2 rating.
However, checking up on this, it turns out that if the "loss of
altitude" and "turning rate" are friendly enough ears and/or
tucks can stay in until the pilot intervenes.
The relevant text is
in the DHV document "clarifications to the construction regulations for
hang gliders and paragliders", on page 16, it says: Rotation: unlimited,
turning rate: very low, height loss: insignificant, re-opening: simple pumping
-> 1. If this happens the minimum rating is: "1".
Roger.
Date: November 14, 2002 05:47 PM
Author: Benn Kovco
Subject: 1-2 rating, pumping ears....
Thanks for that info
Roger. It appears to me that this is coming back to the inherent problem with
DHV testing - that they test a glider on the basis that it is being flown by an
inanimate object/sack of potatoes. It is valid that if I have a small
asymmetric collapse, say the size of one ear, my glider may hold a straight
course forever and have a negligible effect on glide ratio - but define 'simple
pumping'? A simple pump of 20cm, or a simple pump of full brake travel which
may or may not result in stalling the glider?
Date: November 15, 2002 10:26 AM
Author: BC
Subject: Pumping out big ears
The simple act of
pumping out big ears.
(Q) What are we
trying to achieve when pumping our brakes to remove or reinflate from big ears
(A) To help push or move air into/around the wingtip cells to help reinflate
them from big ears, that’s all, So when we think about it what’s better, big
pumps to full arms length, OR little simple pumps on the brakes of about 20cm
travel, my answer is, little simple pumps which are both safer and quicker,
think about it! When we do little simple pumps we move small amounts of air
quicker into/around the wingtips/cells because we can do more little simple
pumps, this simple action will also reduce the chance of stalling or spinning
the wing, along with a little weight shift opposite the side we remove first
helps to reduce the chance of the wing wanting to turn more, again safety
first, small simple pumps & small weight shift must equal more safety, what
will big pumps achieve, very little over small pumps, they require more input
on the brakelines, pull more of the wingtip down into a more stalled wingtip
position, require more weightshift to keep the wing flying straight, and run
the risk of stalling or spinning the wing. Big ears are a safe manouver, we
just have to look at the action required to pump out & release our wingtips
from big ears & small asymmetric collapses.
Date: November 12, 2002 08:35 PM
Author: Chris C
Subject: It seems to me...
It seems to me that
if you are pumping ears out hard enough to cause a spin, you are being way, way
too heavy handed. It's a little perplexing to me when some pilots report having
to pump hard enough to spin or deep stall the gliders to get the ears out. This
seems a little suspicious. Even the comp wing that I fly (very) occasionally
does not have to be pumped very hard to get the ears out--just a couple of
short quick jabs down to shoulder height one at a time--no stall, no spin not
even a change of heading.
I've always been
told that pumping out one ear at a time is the safer alternative. That's the
way I've done it since I've been on wings that have to be pumped out. Even
before that, I always released the outside A-lines one at a time. On many
occasions I've held a single "big ear" in rather than both. That has
never caused problems either--easy to steer with weight shift and it comes out
without pumping.
Also, if you are
low, leave the ears in right to the ground, right up to the flair. The descent
rate is not a problem if you flare aggressively (and smoothly).
Date: November 12, 2002 10:44 PM
Author: mike dufty
Subject: ears that won't come out
I have a UP Pickup
tandem, and the ears on that are very reluctant to come out when it is loaded
up.
I've found that
rolling the glider with weight shift can be more effective than pumping. (I'm
too scared to do a pump big enough to be a spin risk too.)
I note that the
advice in the vibe manual if ears don't come out is to weight shift away from
the ear then pump gently, which seems to agree with what I have found
effective. I have never heard of spins being an issue with the one ear at a
time method of getting ears out, my guess is if your pump is enough to cause a
spin performed on one side it would be enough to cause a full stall if done
both sides at once, I'd rather avoid either.
Date: November 13, 2002 02:09 PM
Author: parker
Subject: dolphin
Several times I've
heard Big Ears mentioned in these threads to get into a tight LZ when high. One
of my instructors taught me how to porpoise (I like "dolphin" myself
:-). Since then I've used this quite often when high and I still have full
active control, which you obviously don't with big ears. You essentially slow a
little below min. sink then smoothly release brakes to trim and do small dive
then immediately slow her down again gently as the dive wants to give you back
height. Wash, rinse and repeat as needed. Practice very high first because you
don't want the glider to really surge, but just gently dive. A good way to dump
10-20ft quick if you need to and still have good flair control.
I used this
technique to get into a small LZ off Mount Aeneas last summer, works great. Had
a good wing sluffer right over the tree-shear too so I shudder to think if I'd
been in ears and wasn't able to active pilot it. Not sure about paramotoring,
but maybe ask an instructor sometime about this. :-)
Date: November 13, 2002 03:28 PM
Author: parker
Subject: flapping
What Richard said. I
was told by one of my instructors to not ever "flap" as it utterly
destroys the flight characteristics of a glider and should be considered
"dangerous". I believe it's because you're flirting too close to
stall point. Not sure if that's true or not, but I really trust my instructor
so won't ever flap. Porpoising can certainly be dangerous as well if overdone,
but with practice I really think it's effective for tight LZs where s-turns
aren't an option.
Date: November 13, 2002 07:28 PM
Author: Chris C
Subject: Flapping...
Flapping is a
"dick around" technique for smooth ridge lift only. We do it at the
local ridge all the time--good for moderate to high wind vertical descent
landings at the lip of the ridge. It is a little extreme, though. You're
basically pulling the glider back as if to stall it, letting off the brakes
fast and quickly checking the surge and repeating over and over rapidly. I
would never "flap" at a mountain site LZ--that would be asking for
trouble and would serve no practical purpose. There are lots of little
"stunts" that are amusing at a ridge lift site but not at all a good
idea in the mountains. That's the main reason we had the big "launch
techniques" debate a while back. Different techniques for different flying
conditions.
Date: November 13, 2002 05:59 PM
Author: mark
Subject: BE
If you use Big Ears
to avoid overshooting a landing field, hold them to the ground (or to the height
where you would normally flair) then release them and flair at the same time.
If the glider does something nasty on exit (stall or spin) it will just
contribute to the flair and not have too many bad consequences. The worst thing
you can do is try to exit ears between 5m and 30m high. If something goes wrong
- you hit the ground - hard.
As for stability and
ears. Conventional wisdom says pull ears when it is turbulent (and you have
height). In my experience, this works for some gliders, but not all. The glider
I currently fly, I would rather not have ears in turbulent conditions.
Try ears when you
are very high. Vary the size, and try with varying amounts of accelerator. You
will quickly learn the best compromise. Note: pull ears before using the accelerator
and release the ears and the accelerator at the same time. For me, if the ears
do not open by them self, I open them by making small weight shift turns from
side to side.
EUROPG FORUM
Roger Barber
Nov
15th
… The big danger when opening big ears is wind
gradient and other turbulence. As the big ears are pumped out, air speed is
lost due to the brake action. If this happens at the same time as air speed is
lost due to wind gradient, then a dangerous situation arises. Turbulence can have a similar effect. I agree
with opening one ear at a time, but one of the dangers is doing it too
fast. It is all too easy to try to open
the second side before the first side has finished surging. The surge is caused by the brake action
followed by the reduced drag of the newly opened tip. This is just the wrong moment to brake the
other side. I believe that most modern
gliders turn very little with one ear in, so long as weight shift is correct,
so there should not be a great hurry if the pilot has confidence and airspace.
Once airspeed has been regained by the pilot and the wing then the second ear
can be pumped out.
For an
experienced pilot that knows his wing, pumping out big ears near the ground in
smooth air with no wind gradient is not a dangerous manoeuvre in my book. ... I
would rate most open take off areas on the brow of a smooth hill as generally
free from bad wind gradient, and most flat landing areas as a much higher risk
unless very smooth and free from obstructions.
I think that seeing experienced pilots doing
big ears to top land is very tempting to intermediate pilots. … It
is also tempting to push lower and lower after finding that it is an easy
manoeuvre with little perceived risk, after all they come out on their own on a
DHV1-2!? It is easy to see how a pilot,
on coming down lower for the first time, can suddenly find that their steering
is inadequate, or their approach not correct.
This would lead to a rush to get the canopy inflated, just at the height
at which the wind gradient is worst, around tree height. This they feel will get them back in control.
Bear in mind that this hypothetical intermediate pilot probably has some cross
bracing.
What I feel we can learn from this is that
training must make it clear why you are taught not to big ears to the ground
(lack of steering), or not open big ears near to the ground (rushing it, wind
gradient, turbulence) and not just say don't.
Steve
Uzochukwu
Nov
18
Big ears isn't perfectly safe in most
circumstances as the reason you have to use it *already* involves one error of
judgement. Opinions are divided as to symmetric or asymmetric exit; I believe
the case for either is glider dependent. Look at gliders, look at their brake
travel, tendency to deep stall, how strongly the ears stay in, how fast they
turn if the ears are exited asymmetrically, how badly they surge if the brakes
are symmetrically pumped. Add other relevant factors. Arrive at a conclusion
for that glider. Then to avoid hospital food, use the conclusion for that
glider only and come to a fresh conclusion for each different glider.
I like to exit big ears that stay in by weight
shifting to either side, the ear weight shifted away from often pops out then
without brake pump.
It appears that people have been assuming
things about big ears for years.
Michel Carnet
Nov
18th:
… The concept of Big
Ears, i.e. the ability of reducing wingspan and surface area in mid flight to
decrease performance, is a brilliant one and hopefully here to stay. It is up
to the manufacturers to make sure that their gliders are safe for Big Ears and
that their user manuals spell out any particular instructions. Hopefully the
new CEN certification (and maybe DHV) will force manufacturers in the right
direction.
John Walton
Nov
18th:
The issue, as I understand it, is the
appropriateness of big ears for students, low airtime and average weekend
pilots flying modern DHV ½ gliders. Some view big ears as being in the same
category as B-Line stalls - ie not to be used casually and certainly not in the
normal flight envelope of the glider.
… It seems to me that the risks with ears can be
managed quite easily:
- pull the ears in promptly, one after the other
- apply speedbar (after you've pulled the ears
in). There are situations where you
might not want the bar on, but it significantly reduces the risk of stall.
- when releasing, we frequently leave the
speedbar on, release the lines together and if they stay in (increasingly
common), release the bar and ease them out with weightshift and judicious
application of the brakes.
… We don't teach big ears near the ground. ... If
I have to bring in ears to land, I hold them in to the ground. I rarely use them for tight turbulent landing
areas, but I will.
…For us, descent techniques are rated in terms
of difficulty, danger and efficacy as follows:
1. Avoid
lift - safe and sensible starting point
2. Figure
8s, wing overs etc - gentle, but not terribly effective
3. Big
ears and speedbar
4. B-line
5. Spiral
- high G force and risk of disorientation and locking in
There are some who add full stall to the end,
but actually the descent rate is less than a decent spiral, and safe and
reliable exit requires skill. Others might add flat spin, but that probably has
a worse descent rate than big ears, requires incredible skill and has an
unpredictable exit. Front stalls,
rosettes and full frontal collapses are no longer considered. So, we teach big
ears. I don't think there is really a
case for reordering this list. If glider
design doesn't take this into account, then I think we have a big problem. Even the critics (Steve U) point out that big
ears is a common technique. So I suspect
the case for gliders to be designed and tested to take account of this is
compelling.
Roger Barber
Nov 19th:
I agree totally with this. … The one common line in all the big-ears
stuff is airspeed. Some canopies are
trimmed slower than others and some slow down more on application of ears. This means that some canopies are closer to
the stall than others (no speed bar). Perhaps testing should pick up the
individual canopy characteristics for big-ears, this should pick up the
canopies with a poor margin above stall with ears in. The most important thing
is for pilots to get to know how fast they should be flying with ears in (wind
noise) and be very aware of the dangers of slowing down for any reason under
ears. I am not talking about braking
here but turbulence, surging and wind gradient.
John Walton
Nov 19th:
Steve commented:
"All rapid descent techniques are risky. We
must teach the risks as well as the techniques."
I could not agree more.