Ventus C, 15m vs 17.6m

I will explain what happens. When flying in the 17.6 configuration, and letting go of the rudder pedals on a straight line, every time a gust pushes the nose to one direction the nose will stay there and you are not flying coordinated any more. Need rudder input to correct. No rudder input and the nose will move from side to side randomly (fish tail). No big deal, but needs attention.
This does not happen in 15 M configuration.
I believe in later Ventuses they increased the tail.
Dan


On Sunday, July 28, 2019 at 4:38:44 PM UTC-4, Frank Whiteley wrote:
On Saturday, July 27, 2019 at 8:40:41 PM UTC-6, wrote:
Longer wings are better for weaker conditions. As mentioned before, the 17.6 meter wing make the glider "fish tail" a bit in a straight line flight.
Dan

I get this in my Kestrel 19, but always considered it to be resulting from rudder flow and the lack of good sealing so the flow attaches and detaches side to side, e.g. laminar to turbulent, thus the movement.

However, you seem to describe something that happens on your Ventus that doesn't happen with in the 15m configuration, is that correct?

Frank Whiteley

On Monday, July 29, 2019 at 10:58:25 AM UTC-6, wrote:
I will explain what happens. When flying in the 17.6 configuration, and letting go of the rudder pedals on a straight line, every time a gust pushes the nose to one direction the nose will stay there and you are not flying coordinated any more. Need rudder input to correct. No rudder input and the nose will move from side to side randomly (fish tail). No big deal, but needs attention.
This does not happen in 15 M configuration.
I believe in later Ventuses they increased the tail.
Dan


On Sunday, July 28, 2019 at 4:38:44 PM UTC-4, Frank Whiteley wrote:
On Saturday, July 27, 2019 at 8:40:41 PM UTC-6, wrote:
Longer wings are better for weaker conditions. As mentioned before, the 17.6 meter wing make the glider "fish tail" a bit in a straight line flight.
Dan

I get this in my Kestrel 19, but always considered it to be resulting from rudder flow and the lack of good sealing so the flow attaches and detaches side to side, e.g. laminar to turbulent, thus the movement.

However, you seem to describe something that happens on your Ventus that doesn't happen with in the 15m configuration, is that correct?

Frank Whiteley

I saw this fishtailing was an issue in the Ventus A&B was it resolved in the C or not?

Thanks

Originally Posted by Mike N.

On Monday, July 29, 2019 at 10:58:25 AM UTC-6, wrote:
I will explain what happens. When flying in the 17.6 configuration, and letting go of the rudder pedals on a straight line, every time a gust pushes the nose to one direction the nose will stay there and you are not flying coordinated any more. Need rudder input to correct. No rudder input and the nose will move from side to side randomly (fish tail). No big deal, but needs attention.
This does not happen in 15 M configuration.
I believe in later Ventuses they increased the tail.
Dan


On Sunday, July 28, 2019 at 4:38:44 PM UTC-4, Frank Whiteley wrote:
On Saturday, July 27, 2019 at 8:40:41 PM UTC-6, wrote:
Longer wings are better for weaker conditions. As mentioned before, the 17.6 meter wing make the glider "fish tail" a bit in a straight line flight.
Dan

I get this in my Kestrel 19, but always considered it to be resulting from rudder flow and the lack of good sealing so the flow attaches and detaches side to side, e.g. laminar to turbulent, thus the movement.

However, you seem to describe something that happens on your Ventus that doesn't happen with in the 15m configuration, is that correct?

Frank Whiteley

I saw this fishtailing was an issue in the Ventus A&B was it resolved in the C or not?

Thanks

Can't say I've noticed this in my Va in 15m or 16.6 which has winglets in both configurations or in either of the b models I used to fly. I suspect that some do it and some don't largely depending on the condition of the aircraft and sometimes as a result of the 'loose nut' behind the wheel :-)

None of the Vc pilots in my old club mentioned this a being a problem either so your guess is good as mine.

I have found that having the yaw string further fwd on the canopy makes it (the yaw string) a lot twitchier than if it's further back so that may be leading to an impression of instability. C/g position also makes a difference too and the further back I went, less stablility in all axes was the result.

2 VbT pilots in my club were quite often ground looping but I didn't have that problem at all with the shorter tailboom on mv Va. All towing from the belly hook, go figure?!

:-) Colin

Again : My Ventus cM doesn't do that.
Maybe I have a special one ?

I had a Ventus B 16.6 and it never did that. It had the C mod on the root fairing.

CH

Good to know. Thanks.

Fishtailing? You mean yaw?

Yes neutral stability in yaw. Requires some rudder input to keep going straight on a bumpy day.
Dan
On Friday, August 2, 2019 at 8:56:48 PM UTC-4, Glidergeek wrote:
Fishtailing? You mean yaw?