Ventus C, 15m vs 17.6m

Just curious, how is the performance of the Ventus C with 17.6m tips installed versus standard 15m with good winglets?

I have done some searching and seen some consensus that the 16.6m tips are typically not used much due to the performance degradation at high air speeds. But what about the 17.6 tips?

Expected conditions would be soaring in Florida.
I also fly Utah, but not thinking I'd need the extra L/D in Utah unless on a weak day.

Also are the 17.6 tips available? What would a set of 17.6 tips cost?

Thanks,
Mike

The 17.6 are similar to the 16.6 tips. None were created before improvements in winglet design so they tend to provide improvements at lower speeds but drop off at the higher end. I can’t remember if the 17.6 C had the same 980 pound limitations as the 16.6 on the B models. This limits the usefulness on stronger days.

The tips are better if they have winglets, but most of these were modified after manufacturer. I would prefer to fly a C in 15m with Maughmer winglets than 17.6 without winglets. The winglets help the Ventus groove and improved the stall characteristics.

Unless the glider has the tips when you buy it is very difficult to find a set later.

The longer tips are nice in lift less than 3 knots, for longer glides at slow speed, and floating around on weak days. Without winglets the glider does have a shorter fuselage and rudder optimized for 15m so yaw can be a factor.

On Tue, 23 Jul 2019 16:16:20 -0700 (PDT), "Mike N."
wrote:

Just curious, how is the performance of the Ventus C with 17.6m tips installed versus
standard 15m with good winglets?

I have done some searching and seen some consensus that the 16.6m tips are
typically not used much due to the performance degradation at high air speeds.
But what about the 17.6 tips?

Expected conditions would be soaring in Florida.
I also fly Utah, but not thinking I'd need the extra L/D in Utah unless on a weak day.

Also are the 17.6 tips available? What would a set of 17.6 tips cost?

Thanks,
Mike

On availability; at one time S-H offered a retrofit kit that allowed
an owner to convert the 16.6m tips to 17.6m tips. This kit was
provided with 17.6m sleeves that were bonded to the 16.6m tips (after
cutting off about 4 inches of the 16.6m tip). The kit included all
required materials, including the epoxy. Not a complex job, but it did
required careful jigging to assure proper alignment.

Details are available in TN 346-11, still available on the S-H
website. Reference is made to drawing HS8-50.307 describing how the
tip extensions are attached.

I purchased and installed this kit on my Ventus cT in the early
2000's. I doubt the kit is still available, but it would not hurt to
inquire.

I typically fly with the 17.6m tips, except in very strong conditions
with water ballast when I drop back to 15m with winglets. I just like
the way the ship looks and handles at 17.6m.

Bob

Thanks for the information.

How is the L/D and sink rate versus the 15 m with winglets?

Again looking at Florida as a primary operations area. So light to moderate lift and not high as compared to Utah or other mountain regions.

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've been flying my Ventus cM in 17.6 m configuration for about 1500 hours, and there is no fishtailing, and you can let the stick go on a thermal. Overall behaviour is very begnin.

Measured performance is 47:1. For European conditions, its max loading of 43 kg/m2 is perfect. I would never consider flying it in 15 m.

On Sat, 27 Jul 2019 19:40:39 -0700 (PDT),
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 have not noticed this flight characteristic in 20 years flying a
Ventus cT.

Bob

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 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