Moth on Foils: 35.9 knots(41.29 mph)

Moth on Foils!---Amlin Day 4

From The Foiling Week:
Provisional Results from Day 4: http://www.foilingweek.com/2015/12/...oth-regatta-day-4-rashley-lead-on-greenhalgh/
https://www.youtube.com/watch?v=xfNauo9Z8e8

 

More non–crashes

I defined what "negative lift" means:

but you choose to ignore it. Based on your argument, the wings of a descending aircraft are generating down force. Not sure that's how other see it.

You continue to argue semantics and never address the actual issue.

You're asserting that if the foil generates less lift than the weight it's supporting, then it's generating down force. If the foil generates zero lift, the boat descends at roughly 1g. If the foil generates down force, the boat will descend at some rate faster than that.

But the bottom line is that even if the foil develops down force, that isn't what causes nose dives. Go ask other Mothies why they go down the mine.

BTW, the use of even if doesn't mean I agree with you, it just means that even if your hypothesis is correct, it still doesn't prove your point.

They just keep coming… fully forward wands without crashes.

https://youtu.be/xfNauo9Z8e8?t=35s

This one has a great rudder ventilation at the same time:
https://youtu.be/xfNauo9Z8e8?t=2m35s

 

Moth on Foils!---Amlin Final

Greenhalgh wins---From The Foiling Week:
http://www.foilingweek.com/2015/12/amlin-international-moth-regatta-final-day-greenhalgh-won/

 

Moth on Foils!

Amlin-Day 5: https://www.youtube.com/watch?v=_t_J4UZCzyw

 

Moth on Foils!----vs The Aussie 18 Fleet!

I've known for some time that Moths were the fastest sailboat under 20'(at least) and certainly faster than Aussie 18's. Well, here's the first video I've ever seen of a Moth sailing right thru the Aussie 18 fleet. On that day, the Moths also were faster than the F18's racing nearby according to PhilS.
Check it out about 7:55 in:
https://www.youtube.com/watch?v=NTpeVAaLIm8

 

Damn it! More wand fully forward, above the water and the boat not crashing! What can it be? Don't these boats know that they're supposed to nose dive? Why is Robert Greenhalgh looking so utterly unconcerned?

https://youtu.be/_t_J4UZCzyw?t=1m6s

 

Moth on Foils!

Sorry you still don't get it, but I guess that's just the way it is..... I've tried to help but I'm done now.

 

You came up with a theory based on watching some videos. I've posted quite a bit of video evidence that contradicts your theory. You have no explanation for why your theory only works sporadically.

I have lots of actual sailing experience so I know what causes the classic Moth nose dive. So does anyone else who's sailed a Moth in chop and breeze.

Attached is a Bladerider main foil profile from AMAC, showing the flap should have a default ±9° of movement. The up movement can be increased to 11° by packing the cavity in the foil, but it also increases the AoA of the foil relative to the strut, so in reality this increases the maximum lift available while not really increasing the flap's ability to reduce it.

This modification was primarily to get the boat trimmed more level. If you look at early Bladeriders, they sailed a little bow up. Changing the angle between the foil and strut allows them to sail flat or a little bow down.

To get more flap up, the back of the strut is trimmed, but only a small amount as over stressing the Sika joint will cause it to fail.

Bruce's comment about if the flap comes up too far the foil will stall was only an extreme case, no one lets their flap do that, the strut stops it (and if it didn't, the system would be limited some other way). Did your +30° -20° cause your flap to stall?

You might also note that those comments are ancient history when people were messing with flexible wands, cable linkages, flaps on rudders and flapless articulated foils. Those days are long, long gone.

BTW, here's AMAC having a classic "ventilation drop" at Garda in 2012. You can see the boat doesn't start to crash until the mainfoil reaches the surface, the wand has been fully forward with max flap up for ages.

https://youtu.be/gK60RZDtnT8?t=5m19s

 

Moth on Foils!

A friend who owns a MachII has helped me understand that there is a wide range of setup for the wand/ flap relationship and so I was wrong in saying-absolutely- that when the wand kicks forward it causes a crash. As I understand it ,it is a matter of set-up and the wand could be set up to have that kind of authority but it is impossible to tell for sure by looking at it. However, that explains the wand springing forward with little or no response from the boat.
So I apologize for the incorrect information.
However, what is still clear is that a wand system still requires the ability to reduce or eliminate lift in order to control altitude. And on multihull foilers the flap movement will likely be much greater than on the Moth in order to facilitate large amounts of downforce from the windward foil.

 

Moth on Foils!

Australian Nationals in Perth: http://www.foilingweek.com/2016/01/standby-for-take-off/

http://sailingresults.net/site/event/151/Overall_2.html?Tkn=19422

 

Moth on Foils! Australian Nationals

Video: https://vimeo.com/150672439

 

Moth on Foils! Australian Nationals, Day 2

Day 2 highlights and video: http://www.foilingweek.com/2016/01/...ship-day2-josh-mcknight-puts-the-hammer-down/

 

Moth on Foils! / Day 3 Aussie Nationals

http://www.foilingweek.com/2016/01/...-perth-turns-it-on-with-flawless-foiling-day/

 

Moth on Foils! Day 4 Australian Nationals

http://www.foilingweek.com/2016/01/...championship-day-4-moths-wilting-in-the-heat/

 

Moth on Foils! Australian Nationals

Josh McKnight wins! http://www.foilingweek.com/2016/01/...h-mcknight-finishes-the-job-in-thunderstorms/