Il giorno giovedì 3 maggio 2018 19:51:17 UTC+2, Piet Barber ha scritto:
I can't imagine a scenario where the nose wheel of a Duo Discus would touch the ground on a winch launch. The tail wheel, though -- you might be on to something.

I'd try to replicate the scenario on the ground. Have two [heavy!] people get into the cockpit, close the canopy, get the tail boom up off the ground and find a way to get the tail wheel to spin up to a good speed. See if the tail wheel is what's making the noise. If after the take-off the tail wheel is still spinning, and slowing down, making noise the whole time.

On Wednesday, May 2, 2018 at 5:45:19 PM UTC-4, Martin Gregorie wrote:
On Wed, 02 May 2018 13:58:42 -0700, AS wrote:

On Wednesday, May 2, 2018 at 3:32:35 PM UTC-4, Paolo Guardigli wrote:
Hello everybody,
we in my Club(Pavullo in Italy) are suffering(2 times) a very strange
vibration of the duodiscus for a minute or so after the glider is
released from the rope,after one minute the vibration is finishing.
We are trying to investigate why it happened but we are not able to
find out the reason.
Does someone already experienced the same problem?

Thanks a lot to everybody

Paolo Guardigli

Hello Paolo - can you be a bit more specific about that vibration? What
is the estimated frequency of that vibration - low, high?
What is vibrating? The wings, the tail-boom or ??

Could it be that the nosewheel got spun-up during the ground run and is
still spinning after release? I'm pretty certain I've noticed that once
or twice in an ASK-21 when the glider wasn't balanced on its main wheel
soon enough.


--
Martin | martin at
Gregorie | gregorie dot org

thanks