LS6 (a, b) NEO

Dan Daly wrote on 9/24/2020 2:59 PM:
On Thursday, September 24, 2020 at 5:07:54 PM UTC-4, Patrick (LS6-b EH) wrote:
We've been looking at this for the LS6-b I co-own. At last check, technical documentation to share with our installer was only for the 4... I'm not sure if they are fully ready on the 6, but they indicate that they are. I gather it's the same part, but may be behind on documentation...

The challenge for us (me) is that the Neo winglets reduce the max cockpit weight (pilot and 'luggage') by 10kg, which for us (me) is a deal-breaker.

I see on their website, that for the LS-4, "...Max. cockpit load may be increased!" Tell them you'd like the same thing for the LS-6b (don't wait for the tech bulletin to come out). If not, maybe ask if a redline reduction could be traded for cockpit load. They won't do these things if you don't ask; they still might not, but at least you tried.

I can imagine why the cockpit load would be reduced, but have no idea why it would
increased!

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

On Thursday, 24 September 2020 at 23:47:32 UTC+1, Eric Greenwell wrote:
Dan Daly wrote on 9/24/2020 2:59 PM:

I can imagine why the cockpit load would be reduced, but have no idea why it would
increased!

The maximum cockpit load can have 3 conditions - the all-up weight, the forward c of g limit, and the maximum weight of non-lifting parts

The last of these is related to the bending loads of the wing. Perhaps if the wingtip is made a bit heavier this relieves bending slightly and the max cockpit load might increase, depending on the other limits.

Admittedly this is speculation and could be ill-founded.

andy l wrote on 9/24/2020 5:20 PM:
On Thursday, 24 September 2020 at 23:47:32 UTC+1, Eric Greenwell wrote:
Dan Daly wrote on 9/24/2020 2:59 PM:

I can imagine why the cockpit load would be reduced, but have no idea why it would
increased!

The maximum cockpit load can have 3 conditions - the all-up weight, the forward c of g limit, and the maximum weight of non-lifting parts

The last of these is related to the bending loads of the wing. Perhaps if the wingtip is made a bit heavier this relieves bending slightly and the max cockpit load might increase, depending on the other limits.

Admittedly this is speculation and could be ill-founded.

Winglets increase the lift of the outer end of the wing. This shift in wing lift
distribution increases the bending moment on the spars; reducing the cockpit load
could compensate for the increased bending moment. I'm guessing the winglet weight
is not enough to prevent the increase. I'm basing this on retrofitting relatively
heavy winglets to my ASH26E, and noticing in flight that the wing tips were higher
than before. I confirmed the extra bend using before and after pictures taken from
the cockpit.

But, I don't know why they did reduce the cockpit load, so I hope someone will
find out and tell us.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

On Thu, 24 Sep 2020 15:47:27 -0700, Eric Greenwell
wrote:


I can imagine why the cockpit load would be reduced, but have no idea why it would
increased!


In the case of the LS-4 the standard winglets reduce cockpit load
quite a bit, and compared to the standard winglets the NEO winglets
increase cockpit load again.

Cheers
Andreas