Righto... here is the video at last!!!
Sun, 7 Dec 08 05:53
Hi all, sorry for the wait but it wasn't for lack of trying on our part.
http://www.youtube.com/watch?v=EfJK5ycx_hg
An even higher res version will be available for download off this site later today.
On the first run I had the wing sheeted in to 15-18 degrees. On the second fateful run I focused on bringing it in to the optimal 10 degrees. The wind had built by a knot or so and although the mean average was around 23 knots... that means gusts to 25. We have taken the B+G wind sensors off the back for record runs so I can only guess that a gust like this and having the wing in hard is what caused VESTAS SAILROCKET to accelerate so hard to the point of overloading. Perhaps I should have been more cautios but after the stability and control of the first run and previous runs in even stronger conditions I simply thought that this was not the time to hold back. It is an 'outright world speed sailing record' attempt after all. In the end it was no doubt a combination of effects brought on by the newfound speed and high apparent wind speeds that come with it. VESTAS SAILROCKET would have turned that 23 knot breeze into a 50+ knot apparent wind gail coming from around 26 degrees off the bow.
As you could imagine, we did do some substantial damage to the wing. You don't get away with a crash like that lightly. Thanks to the brilliant design by AEROTROPE... it has survived and it is fixable by us here in Walvis Bay. We are already well into it and hope to be back on the water for more runs in the near future.
More important is the issue of understanding and preventing this from happening again.
Malcolm is working hard on this with input from all the team. We want to dampen the whole boat down a little and approach these speeds again from a point of safety. We will angle the foil a few degrees more so it is pulling the front planing surface down harder and stand the rig up so it is pulling up less. We had already begun moving in this direction and you can see that the leeward pod isn't flying quite as high as it had in some of the previous runs. We think that the main foil may be flexing a little more than we anticipated and that we should speculatively account for this with safety in mind. We will also look at adding 'lift-spoiling' devices on the inboard end of the beam. From my perspective I will be a little more cautious of how aggressively I sheet in. The main flap wasn't even pulled in on the flying run. When it is it helps keep the nose down.
The team is doing a brilliant job here and yesterday we really began to make solid progress towards getting back on the water. It is just beginning to dawn on us what we have achieved and the potential of where we are going. To make such huge gains at this end of the speed range is staggering.
We have had so many people calling, e-mailing and simply dropping in to give their support and encouragement. I want to let you all know that we appreciate it and every e-mail and comment posted here gets read out, saved and shared.
It was really nice to get one from the Hydroptere team. It is great to have such a hot boat to compete with. We both desperately want to be number one but I think we both appreciate the other teams efforts and presence. In the end we sent them all our GPS data to see if they got the same numbers as we did using their programs. They did. Although we are ahead of them now... I by no means think we will be for long as I'm sure they are going to hungry to get their 'fastest boat' title back.
On another note, On the record run... after 40-50,000 odd sea miles... my little koala mascot flew out of my rash vest and is gone. I figured he either said enough was enough... or figured I didn't need him any more... On the next run we flipped the boat!!! Good luck out there Kev, I hope you enjoyed all the sailing as much as I did. You checked out in style.
Cheers, Paul.
p.s. the helmet stays. There is a real helmet inside by the way. The fairing will be heavily drilled and cut so as to snap off with minimal force. My neck is a bit sore and yes I was very lucky.
VIDEO
Submitted by Frank Neuperger on Thu, 12/11/2008 - 05:18.Paul,
Can you give us another (36 MB?) video that starts at 3-4 seconds before the loop and ends at 3 seconds after the loop. i.e. full HD resolution for ~10 seconds.
Frank N
Trifoilers 88 and 95
CROSSBEAM LIFT
Submitted by wardy89 on Mon, 12/08/2008 - 22:21.i have just got someone i know to have a look at the video, who knows more about aerodynamics and wing sections than i do and he agreed with what i said! this is what he said!
"it is Bluebird all over again, too much lift getting into ground effect and no aerodynamic controls to get it down again"
u may already have ways of controlling this but i am not sure!
well that is my opinion on what happen anyway!
There appears to be a flap
Submitted by VTsailor on Tue, 12/09/2008 - 02:00.There appears to be a flap on the trailing edge of the beam and as far as I can tell the purpose of the foil shape of the beam is to lift the float and wing clear of the water. If this flap is something you dial in then as conditions change the lift generated by the beam must as well... maybe some kind of spoiler that is triggered by the float clearing the water would do the trick. not a huge spoiler mind you but one that would just take the edge off.
My other thought would be a laser rangefinder that would trigger a large spoiler (ala Nascar) prior to reaching the point of no return. The wrench in all of this is the possibility that Ground effect is taking over which changes the aerodynamic equation dramatically and poses its own set of solutions.
PS I am sure there is a simple and elegant solution.... its kind of like breaking the sound barrier without swept wings....
CROSSBEAM LIFT
Submitted by wardy89 on Mon, 12/08/2008 - 19:28.i have been reading the comments by others about the crossbeam perhaps producing lift! i hadn't really thought about it before others mentioned it (which is stupid really as i fly model aircraft!) but the more i look at the video the more i am sure that the cross beam is acting as a wing and producing lift! and that u have just found the speed at which the lift produced by the airfoil crossbeam is great enough to overpower the hydrofoil resulting in takeoff! but i don't know because i don't know what the airfoil section of the crossbeam is so i am not sure wether it would produce lift! well that is what i am thinking at the moment anyway! what do others think?
Crossbeam lift
Submitted by Frank Neuperger on Thu, 12/11/2008 - 05:05.That crossbeam section looks symmetrical in shape and I am guessing (hoping ) they had adjusted its attitude to one that is lift neutral so that it does not lift at any speed. Another poster mentions the possibility of ground effect kicking in and that may be a possibility but I would not expect the ground effect force to be insignificant compared to the nominal upwards force vector component from the wingsail. I am still thinking that a gust or bounce of the hull induced a lateral stress on the foil that caused cavitation or ventilation and that caused a momentary loss in downforce .. etc. .. see the rest of my earlier post .
Frank N Trifoilers 88 and 95
Koala...
Submitted by modelyacht on Mon, 12/08/2008 - 17:20.Funny about losing the Koala mascot as you reached your goal of being the fastest sailboat on the planet.
Did you know that Dennis Conner lost his Top Gun hat during the last race of the America's Cup in 1987?
Taking Flight
Submitted by james on Mon, 12/08/2008 - 10:13.I would like to congratulate this determined and hard working team. What an awesome achievement. I know you guys will be back at it hitting faster speeds in no time.
Paul, you didn't mention what the control of Vestas Sailrocket was like on the ballistic run. I was wondering if you noticed any difference in the helm as the bow lifted out of the water? Did the boat begin to float to leeward any once the main foil came out of the water or did it continue on course through the air?
crossbeam lift
Submitted by Frank Neuperger on Mon, 12/08/2008 - 08:48.First of all congrats for a great acheivement.
As I loged on to post my observation of the crossbeam airfoil, I noticed that the poster before me got to it first.
With the pronounced airfoil on the crossbeam, it seems plausible that if the crossbeam airfoil lifts for any reason such as the nose bouncing on a wave or lift due to loss of (water) foil down force you could end up with a slight "Lift" angle of incidence, it will then lift even more and then as it lifts more, the angle of incidence to the apparent wind increases even more (in the vertical plane of interest) and then you get even more lift and....... and ....you end up with a loop. In control we call this positive or regenerative feedback and if uncontrolled, it generally ends up with the system going to one of the "rails" (limits)... as did SAILROCKET vertically until the crossbeam air foil stalled and the intertia of the tail and the rest of the boat kept the rotation going to complete a near 180 backflip. You see a similar scenario most often with power race boats and somtimes with racecars. I look forward to you getting it under "control" and hammering that record again!
Frank N Trifoilers 88 and 95
Crossbeam lift
Submitted by VTsailor on Mon, 12/08/2008 - 05:33.Congrats on the runs and thanks for the amazing footage (a nice treat with the snow flying here). In stepping through the video I cant get over how level the crossbeam remained throughout the event, as if it was the center of rotation. As the lift started it seems like there is a huge flex on the beam first and then it lifts, the combination of these observations and the apparent lack of torsion created from the wing makes me wonder if the left generated by the crossbeam at the new wind-speed didn't influence the loop.
Thanks for going above and beyond with the live blog from the beach, it has made word of you guys headed across the lagoon that much more exciting.
hydroptere
Submitted by mathieu on Sun, 12/07/2008 - 23:58.first I would like to say how amazing is this video. It seems that if sailrocket had not flew, she would still be accelerating !!
seen on hydroptere website:
http://www.hydroptere.com/
"
Sunday December 6
Australian Paul Larsen and his speed machine SailRocket recently reached a new stage in the absolute race with the sail speed records , by carrying out a run with 47,36 knots out of 500 meters.
Alain Thébault and his team greet this performance.
Alain Thébault: " what Paul and its team did is spectacular. We are very happy. Just like us, they have been working hard for years and perseverance starts to pay. The race do not stop there, we are more determined than ever facing our Australian friends! "
The next window weather, for the flying trimaran, is announced for the middle of week. Hydroptere should thus go on the speed basis to benefit from the Mistral.
"
poor translation from babelfish
Mathieu
Video Download
Submitted by admin on Sun, 12/07/2008 - 23:09.You can download the high-res (37MB) version of the video here:
http://www.sailrocket.com/movies/Vestas%20Sailrocket%20goes%20Ballistic.mp4
Right click on the link, and Save Target As... to download.
video!
Submitted by wardy89 on Sun, 12/07/2008 - 12:50.great video! it is quite strange seeing the video now after all the talk about it! from what i can see u got off very lightly!
by the way i love the quote from the video "tear a new asshole in speed sailing" it is apsalutley brilliant and as someone said on the comments on youtube it may well be speed sailing's quote of 2008!
again congratulations on the record, keep us all updated with the repairs and we all hope to see u sailing again soon! that outright speed sailing record is waiting for u!