I appreciate its a tad off-topic, but... these Cub aircraft with big
wheels seem to defy most of my notions of where its rational to land
(and how!)...:
http://au.youtube.com/watch?v=6o3RK-RpJmY
Sort-of on optic again: My Stemme manual is very clear about landing
wheels up into water - and into unknown-ground field landings as well
- but the undercarriage - and its height - are somewhat unusual for a
sailplane.
For interests' sake, here is the entire 'water ditching' section of
the Stemme manual:
3.9.3.3 Emergency landing on water (ditching)
An emergency landing on water is accompanied with risks and should
only be undertaken as a last option.
If a ditching is unavoidable, it is recommended to land in the
sailplane configuration and, due to the special
design of the landing gear, with the landing gear retracted. Cabin
ventilation and emergency-window must
be closed first.
Approach and landing:
• approach GLIDER CONFIGURATION
• landing gear UP
• ventilation, emerg.-window CLOSE
• final and touch-down MINIMUM SPEED
If the a/c dives after touch-down and does not rise to the surface
soon and the front cockpit stays below the
water surface, it is recommended to open emergency-window and
ventilation to accelerate pressure balance
because it could be impossible to open the canopy due to a high
water pressure. If necessary, opening of the
canopy can be improved by pulling the emergency canopy handle after
opening the canopy locks and the
"R5ger"-hook (see section 3.2 "Canopy Jettison"):
• lateral canopy locks OPEN
• "R6ger"-hook UNLOCK
• canopy emergency handle PULL (red handle on the instrument panel)
• ventilation, emerg.-window OPEN
NOTE: Experience shows, that gliders tend to submerge at touch-down
instead of sliding on the water
surface. When the cockpit is pressed below the water surface, mostly
only for a short moment, it is
almost impossible to open the canopy.
This is clearly a last-resort thing to do. If I don't ever have to do
it in practice, that'll be soon enough, thanks.
Simon
On 29/04/2008, at 7:45 AM, DMcD wrote:
On Mon, Apr 28, 2008 at 9:42 PM, Ulrich Stauss <[EMAIL PROTECTED]>
wrote:
Another reason for having the wheel down in case of a water landing
is that you'd generally try to land close to shore where the water
might be (very) shallow with rocks and other nasties lurking under
the surface. The undercarriage provides more buffer than the bits
material of your choice under your backside.
That would appear to be a practical reason why it is done.
My contact has this to say:
Tests were carried out on a lake in Germany by Walter Schneider and
Wolf Lemke of LS fame. They ditched an LS1 prior to the World
Championships in Finland because they were worried about the lack of
land out options and the proliferation of lakes.
They assumed that landing wheel up would be the preferred option,
but discovered that the glider 'bounced' off the surface and dropped
a wing as the fuselage entered the water because of it's shape. They
tried it again with the wheel down, deliberately put the tail down
first and discovered that the wheel acted as a gentle brake and
controlled the whole process much better. I've seen the photographs,
so they may be available on some German web site somewhere.
During the Worlds in Borlenge Sweden, when I was crewing for Andy, a
couple of gliders were put into lakes and all came out okay. I'm
pretty certain they landed wheel down trying to put them up the
beach. The major issue with such landings is that the glider sinks
VERY quickly (regardless of wheel position) and the electrics can
cause problems as you'd expect. It's certainly not recommended!
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