DG-1000 undercarriage collapses and inadvertent extensions ?

On my ASW-27 the gear warning will come on if the gear is not all the
way in the locked position and the spoilers are activated.
I installed an intermitting sound alert that beep and a LED next to
the airspeed indicator that flashes. Now all I need now is a 25k volt
discharge to my butt and then maybe I will not land gear up . ;-)

Ken (KP)

Derek Copeland wrote:
Our club in the UK has two DG1000s with the two wheel
tail dragger configuration. We have had numerous undercarriage
collapses on landing, but as far as I know no unwanted
extentions in flight.

The problem seems to be that a great deal of force
is required to get the gear over-centre and that the
lever in the front cockpit has a very long throw. People
with short arms, or who are not very strong have a
real problem getting the wheel to lock down. I personally
find the U/C reasonably OK to operate from the rear
cockpit, but very difficult from the front. And yes
I have had the U/C retract on landing, which was very
embarassing.

The whole thing seems to be very poor from an ergonomic
point of view.

Anyone seen this problem in the 505?

Thanks,
Shawn

On Wed, 18 Apr 2007 20:41:28 -0600, Shawn
wrote:

Anyone seen this problem in the 505?

Nope. No problem at all in the 505.

Bye
Andreas

While flying a 1000 at the Seniors a couple years ago I heard the gearing
warning horn on short final, checked that the gear handle was down, landed,
rolled 2 meters and the gear collapsed. I assumed I hadn't "seated" the
handle right and flew the next day without further investigation. The gear
collapsed again.

Looking into the landing gear operation revealed the problem and it is not
an "over center" condition. The down lock for the 1000 gear is a steel plate
under the left plastic trim panel that hides the gear push rods running
between the two cockpits, just below the canopy rail. There is a tab on the
push rod that is supposed to rotate behind a steel plate far enough to
prevent the push rod (and handles) from moving out of the down position.
This steel plate was incorrectly positioned so that the gear was barely safe
in the down position, but with the slightest rotation inboard or vibration
on landing it became unlocked.

It was a very simple matter of repositioning the plate to correct the
problem.

Karl Striedieck



"Andreas Maurer" wrote in message
...
On Wed, 18 Apr 2007 20:41:28 -0600, Shawn
wrote:

Anyone seen this problem in the 505?

Nope. No problem at all in the 505.

Bye
Andreas

On Apr 15, 3:47 am, Geoff Vincent
wrote:
Hi all,

This, together with the countless incidents involving DG-300 U/C
collapses isn't it about time the manufacturer got the engineering
design right?

Geoff Vincent

I'm not sure past issues with the 30x and any current issues with the
1000 are directly related, but what amazes me is the large percentage
of DG-30x owners I've spoken with who do not know of the undercarriage
handle TN 359/22. I've even spoken with a DG-303 owner who had a gear
collapse, had the gelcoat repaired and was back flying but was still
not aware of the TN (kind of makes me think he should find another
repair shop as well). The original rubber pressure block and metal
plate with a little metal knub that was supposed to hold the handle
locked was really a pathetic design and likely to come out of
adjustment, the TN adds a coil spring that keeps the handle more
firmly rotated in place. A few hundred dollars well spent. The DG-30x
(and other gliders) also need to have their U/C overcenter locking gas
strut inspected periodically.

Darryl

Jeremy's uninformed guess is perfectly correct. The
problem is that to get the U/C properly overcentre
requires a really long and hard shove forward, and
there is only about a one mm difference in the position
of the lever between the U/C being locked down and
not locked down. The more recent of our two DG1000s
has a small detent in the sidewall to indicate that
the gear is properly locked down, but is still far
too heavy and awkward to operate, especially in the
front cockpit. On a recent flight it took me 10 attempts
to get the lever into the detent, and I am not exactly
small or weak.

Derek Copeland

At 19:36 18 April 2007, Stefan wrote:
Jeremy Zawodny schrieb:
Derek Copeland wrote:
Our club in the UK has two DG1000s with the two wheel
tail dragger configuration. We have had numerous undercarriage
collapses on landing, but as far as I know no unwanted
extentions in flight.

Our club has #23 and has put *a lot* of hours and
landings on it in the
last few years. No retract problems so far on landing.


My completely uninformed guess is that those unexpectedly
retracted
gears were just not locked. I *almost* landed with
an extended but
unlocked gear myself, but recognized the situation
just in time. It
takes a lot of force to correctly lock the gear. Start
the process early
and always visually double check the handle position.

Just for the record, that was Stefan, not me. :-)

As far as I know, I've always had the gear locked.

Jeremy [knocking on wood...]

Derek Copeland wrote:
Jeremy's uninformed guess is perfectly correct. The
problem is that to get the U/C properly overcentre
requires a really long and hard shove forward, and
there is only about a one mm difference in the position
of the lever between the U/C being locked down and
not locked down. The more recent of our two DG1000s
has a small detent in the sidewall to indicate that
the gear is properly locked down, but is still far
too heavy and awkward to operate, especially in the
front cockpit. On a recent flight it took me 10 attempts
to get the lever into the detent, and I am not exactly
small or weak.

Derek Copeland

At 19:36 18 April 2007, Stefan wrote:
Jeremy Zawodny schrieb:
Derek Copeland wrote:
Our club in the UK has two DG1000s with the two wheel
tail dragger configuration. We have had numerous undercarriage
collapses on landing, but as far as I know no unwanted
extentions in flight.
Our club has #23 and has put *a lot* of hours and
landings on it in the
last few years. No retract problems so far on landing.

My completely uninformed guess is that those unexpectedly
retracted
gears were just not locked. I *almost* landed with
an extended but
unlocked gear myself, but recognized the situation
just in time. It
takes a lot of force to correctly lock the gear. Start
the process early
and always visually double check the handle position.

Happened to me in a 505, & I'm a long-armed gear slammer.
Jim
"Shawn" wrote in message
. ..
Derek Copeland wrote:
Our club in the UK has two DG1000s with the two wheel
tail dragger configuration. We have had numerous undercarriage
collapses on landing, but as far as I know no unwanted
extentions in flight.

The problem seems to be that a great deal of force
is required to get the gear over-centre and that the
lever in the front cockpit has a very long throw. People
with short arms, or who are not very strong have a
real problem getting the wheel to lock down. I personally
find the U/C reasonably OK to operate from the rear
cockpit, but very difficult from the front. And yes
I have had the U/C retract on landing, which was very
embarassing.

The whole thing seems to be very poor from an ergonomic
point of view.

Anyone seen this problem in the 505?

Thanks,
Shawn

Between two club owned and one privately owned DG1000
gliders at our site, we have so far averaged about
1 undercarriage retraction on landing approximately
every 200 flights. Probably all of these were failures
to lock the U/C down properly, for the reasons stated
previously. The only good news is that a reasonable
landing on smooth grass doesn't seem to cause much
damage beyond ripping off the odd undercarriage door.


Getting a big group of people together to lift a stranded
DG1000 off the ground after an U/C collapse, so that
the wheel can be lowered, has almost become a routine
occurrence at our club!

Sometimes the U/C locks down quite easily, but on other
occasions it’s like pushing against a brick wall! I
thought that it might be related to airspeed, as you
have to push the wheel forward into the slipstream,
but on the last occasion I had difficulties slowing
down to the stall made no difference.

BTW I flew the DG1000 prototype demonstrator on a number
of occasions and didn't find any problems operating
the undercarriage, so it is something that has crept
in on production models. Neither have I had any problems
operating DG500 (3-wheeler) or DG300 undercarriages.

Derek Copeland

At 04:54 22 April 2007, Jim Hultman wrote:
Happened to me in a 505, & I'm a long-armed gear slammer.
Jim
'Shawn' wrote in message
...
Derek Copeland wrote:
Our club in the UK has two DG1000s with the two wheel
tail dragger configuration. We have had numerous
undercarriage
collapses on landing, but as far as I know no unwanted
extentions in flight.

The problem seems to be that a great deal of force
is required to get the gear over-centre and that
the
lever in the front cockpit has a very long throw.
People
with short arms, or who are not very strong have
a
real problem getting the wheel to lock down. I personally
find the U/C reasonably OK to operate from the rear
cockpit, but very difficult from the front. And yes
I have had the U/C retract on landing, which was
very
embarassing.

The whole thing seems to be very poor from an ergonomic
point of view.

Anyone seen this problem in the 505?

Thanks,
Shawn

Derek Copeland wrote:

Getting a big group of people together to lift a stranded
DG1000 off the ground after an U/C collapse, so that
the wheel can be lowered, has almost become a routine
occurrence at our club!


How do you go about this, in detail?



Sometimes the U/C locks down quite easily, but on other
occasions it’s like pushing against a brick wall! I
thought that it might be related to airspeed, as you
have to push the wheel forward into the slipstream,
but on the last occasion I had difficulties slowing
down to the stall made no difference.


Have you tried under various g-load conditions?



Jack