Greenbird

End to test period

2008-12-01T16:15:19Z

Well, once the lake was dry enough to get back to the camp, it was very clear that it was going to take at least another few days, for it to dry enough to be able to run. With no wind forecast for the next week, we are simply out of time for this test window. Rain is not uncommon for this time of year, so it is not a huge surprise, but normally the rain is accompanied by wind in advance of the fronts and I was hoping to be able to utilise this wind before the rain stopped play. Unfortunately, the system that dropped this water, was a very slow moving low, without any significant pressure gradients, so unusually, it managed to rain without any wind in advance. All very annoying!

However, despite the lack of wind, I did get one day of sailing in, clocking 60 mph in light wind. Although this is only a fraction of the vehicle’s potential, it was fast enough to demonstrate that everything is working perfectly. My concerns over the rear suspension on the bumpy surface was unfounded and that gives me a lot of confidence for the next weather window in March.

As all the landsailors had disappeared after the Nalsa regatta washout, I dismantled the Greenbird by myself, which is always a challenge, but after a long day, it is all safely back on the trailer, and off the lake. The craft will be stored locally over the winter, and be ready for the next land record opportunity in March.

The next challenge for us is going to be the ice record in Montana in January.

Rainman

2008-11-27T10:41:12Z

Ivanpah becomes a wet lake

Was woken up this morning at 4.30 am, to the sound of rain on the window. Two hours of pretty good downpour flooded most of the lake, but, all is not as bad as it seems. There area has been exceptionally dry for the last few years and most of this should be absorbed in the next day or two. Some wind is forecast for the weekend, so we are hoping it is going to be dry by Friday.

For now the lake is closed, with the Greenbird marooned on the edge. Hopefully we will be able to get back to it tomorrow, and download the data from the weather station, to see exactly how much rain fell during the night.

As long as no more rain falls, we should still be able to test on the weekend.

Closed due to rain

Watching the weather at Ivanpah

2008-11-25T16:02:29Z

We are now well into our second week of above average temperature, hot windless days, but hope is on the horizon! A BIG change in pattern is about to happen, with a big low pressure system off Alaska, poised to throw us some cold fronts around the middle of next week. The first storm is expected on Tuesday afternoon, while the second system will hit us on Thursday (Thanksgiving Day) or Friday. Although strong winds are not forecast, there are normally localised strong winds accompanying the fronts. The big concern for us is how much moisture and precipitation will also be brought by this system. Forecasts are mixed, with some saying most of the moisture will be lost in California, while other predict rain deep into southern Nevada. Although very heavy rains are uncommon, Las Vegas did record 0.6 inches on one day on November 30th 2007, so it is not out of the question. All we can do is try to utilise any wind before any showers hit us. If it does start to rain, we need to get off the lake ASAP, before the hard dry clay turns to mud!

The flip side of the having a week or two of no wind is that I have been able to finish a large number of jobs and perfect any snagging systems. I have also built a new faring on the front pod, to remove a turbulent zone behind the front wheel and help deflect stones that were being flicked up by the front tyre and on to the canopy.

I have installed a new GPS system, called a Driftbox, kindly donated from Race Logic, that is not only super accurate, it also measures the exact sideslip angle (drift) and records all the information onto a flash card for analysis later. The cockpit is pretty cramped, so it is tucked away behind the hydraulic steering system and and can just be seen through the steering wheel.

Simon Fitzerald from BHP Sport (Greenbird film crew) is now here with me, providing very welcome company. Should the weather play its hand, Simon will be capturing any action on the very latest Sony HD equipment. He has already spent a couple of days rigging the Greenbird with an array of recording equipment and miniature cameras, to get the vital on-board shots, which will hopefully give you an idea of what it is like to drive this crazy machine!

Watch the weather, pray for wind, and no rain!

First tests on dirt in light winds

2008-11-20T16:25:39Z

Here’s a couple of photos of our first test run on dirt in light winds (13-20 mph) at Ivanpah the other day. Fingers crossed for a bit more of a breeze during the predicted shift in weather system next week.

Greenbird on dirt at Ivanpah

2008-11-19T11:46:44Z

Now fully set up at Ivanpah. Another day in the hot sun, ironing out any last glitches and fitting a few new systems. No wind forecast today, and until 2pm that was the case, absolutely nothing.

Then, from nowhere, the wind set in blowing 18-25 mph, almost instantly, and I was not ready!

These are not record wind speeds, but very good testing winds. I worked frantically to finish the hydraulics and bleed the system and finally got the wheel covers on at about 3pm.

Pushed it out on to the playa and sure enough, the wind meter was now reading 13 mph, where it stayed till sunset (our self starting threshold is 18 mph of true wind).

Typical. However this is the nature of the desert, sometimes a good forecast does not materialise, and other times a nothing forecast suddenly becomes good for an hour.

There is a better forecast for tomorrow, so hopefully, we will get some runs in.

Arrival at Ivanpah playa

2008-11-19T10:22:01Z

Arrived today at Ivanpah after the weekend gathering supplies and tools. I did not expect to be back here now, when I left the ice craft up in Montana, so I left a lot of crucial spares and tools with the ice yacht and have had to duplicate a lot of that stuff now unfortunately.

However, I should get my lake permit this morning so setting up this afternoon on the lake. A lovely sunny day and some wind forecast for Friday Saturday so a good opportunity for an initial test.

I have got a 3g card for my computer, so I have fast internet direct from the lake, which will prove invaluable no doubt.

Setting up by myself, so might take a little longer than normal, but hopefully send pics this afternoon.

Greenbird - meet Vegas

2008-11-19T11:06:18Z

Picked GB up from warehouse in LA this morning. Now stationed at the test location near Vegas.

Can’t get the lake permit till Monday, so setting up next week. Will be on location till 1st December

Going Stateside for landcraft testing

2008-11-06T10:23:58Z

Landed in San Fransico Nov 4, on my way to Nevada for an essential test period. I will be using the November weather window to evaluate the performance on dirt before the best weather next March/April. However, it is not out of the question that we may get perfect weather during November! If this happens and we do get a record speed, then we are preparing to be able to move quickly and capitalise upon it.

It seems that over the last 8 years, the weather is getting more and more unpredictable and therefore we can’t afford to waste any opportunities if they arise.

I have spent many days over the past few weeks analysing weather records for about 12 possible locations in the US. What is very apparent is the weather event that the ‘Iron Duck’ had in 1999 (current record holder) really was pretty unusual, in the strength, steadiness and duration of the wind event. There has probably only been one or two occasions in the last 12 years when this has happened. This is not to say that strong wind events don’t occur, just they are of shorter duration and more random.

Therefore, I intend to spend as long as it takes on standby to wait for that opportunity. We can’t sail past the end of November, but once the playa’s dry in mid March, there is pretty much a constant window through to July (at a variety of venues). It may well be the case that I have to spend 4 or 5 months sitting in deserts or frozen lakes, but this is what it is going to take.

50 Knot ‘Barrier’ Broken

2008-11-04T15:57:06Z

On Saturday 4th of October the world speed sailing record (on water) was increased to 50.56 knots (93.6 Km/h) by kite surfer Alexandre Caizergues (FRA) at Luderitz in Namibia. This phenomenal achievement eclipsed the previous official record of Robert Douglas (also a kitesurfer) at 49.84 knots. Before Robert, the record was held by windsurfer Antoine ALBEAU (FRA) at 49.09 knots.

So why is this phenomenal? Well, it is phenomenal because it is an incredible feat of skill, strength and endurance. The record was set in winds averaging around 40 knots obviously with higher gusts. To stand up in this is difficult, but to control a kite and board over 500m (the record distance) is amazing. Furthermore, to record an average of 50, you need peak speeds well above this, and according to Alex’s GPS, he hit 58 knots peak speed with a 54.5 knot average over 200m. This is skill indeed and we at Greenbird salute you all.

So what’s with the 50 knot barrier? For years speed sailing records were set in boats, then later sailboards. Both these require a foil in the water to generate the side forces necessary to counteract the force from the sail. As the boats and boards got faster and faster, the rate of increase per record decreased and it seemed like we were approaching a theoretical limit due to the amount of force a water foil can hold before it cavitates (or more likely ventilates). To avoid a very lengthy technical discussion on the theory of cavitation and ventilation, it quite simply means, that at some point (at very high loading) the flow detaches from the low pressure side of the foil and almost all lift is lost, while extra drag is created. This transition normally results in catastrophic wipe-out, so lots of work was put into trying to delay this transition. We all also knew there are such thing as super cavitating (or fully ventilated) foils that work efficiently at high speeds way beyond the transition speed for conventional foils, but these are very poor at low speeds so switching from one type of foil to the other was always going to be tricky. It became pretty clear that this transition speed from attached to ventilated flow was around 50 knots and hence this was initially proposed as a physical barrier for speed sailors. Strangely enough, it turned out that ventilation was successfully delayed on windsurfer fins and the fastest boat, Macquarie Innovation and the limiting factor became drag. Had they been able to reduce the drag further and increase power, it would have come back to ye olde foil ventilation.

So why have Kite surfers eclipsed it so seemingly effortlessly? Well, a couple of reasons. Firstly, the kites are higher in the air than a windsurf sail meaning they are effectively sailing in higher wind speeds than their windsurf counterparts. Secondly, the boards already work exactly like a super cavitating (or fully ventilated) foil which uses mass (or momentum) transfer to achieve a reaction and hence side force. Using this principle, there is no hydrodynamic limit other than drag (air and water) factors to limit top speed. Therefore, I predict a new barrier will soon be established, determined by the sum of the aerodynamic drag from the kite, line and person, plus the hydrodynamic drag from the board.

I am not going to propose what that new speed limit might be, but there will be a limit ,and once the technical evolution is fully evolved (as it pretty much is in windsurfers) the top speed will be directly proportional to the wind speed. So, we may see different record categories for different wind speeds, which would give more credit to technical efficiency rather than just skill, body weight and brute force.

So will that be the final barrier? No far from it. The problem with kite surfers is that the maximum kite force will always be limited by the weight or strength of the person. To get real ‘pull’ you need proper ‘grip’ in the water and this can only be done with some kind of submerged foil. Once you get this to work, you can have a more powerful, efficient, high aspect wing in the air. Then there is a whole new ceiling. Maybe we wil be talking about the 100 knot barrier in a few years?

So how is it done, exactly? Don’t think I am going to tell you in a single blog, but one thing for sure, once the land and ice records are done, I am very much back on the case!

Here are a few links of interest, showing some of the different principles currently being tried by teams around the world:

Sailrocket - http://www.sailrocket.com
Macquarie - http://www.macquarie.com.au/speedsailing.htm
MoS - http://www.mastersofspeed.com
Luderitz - http://www.luderitz-speed.com

Rain stops play…

2008-10-17T10:46:54Z

After dinner around the campfire end of last week, with a group of landsailors from Perth, I went to bed around midnight, with the sound of rain still falling on the tin roof of the old mining exploration caravan we are staying in. In the morning the rain had stopped, but we found the camp area had turned into a bit of a quagmire, which indicated a lot of rain had fallen over the last 12 hours. We skidded down the muddy hill to the foil trays we had left on the lake surface to measure the amount of rain, only to find one of them had floated away, which gives you some idea of what we were looking at. The other tray indicated that between 15-20mm had fallen in the night, and the sky was still not clear. Later that morning more thunder clouds dropped another 5-10mm.

This had flooded the entire surface of the lake and has rendered it unusable for possibly another month, which sadly means an end to this year’s land record challenge, which is a very disappointing blow to us all. The Greenbird was in fantastic shape to shatter the record and it is very frustrating not to get any high speeds in whatsoever.

So why the peculiar weather and why could we not predict this? I will be going into a more detailed weather analysis in the next blog post, but in brief, July saw twice its monthly average fall in 2 days at the end of the month, then August saw its monthly average quota fall over the last 12 hours. If the rain comes in smaller showers with regular intervals, it can evaporate quicker and soaks into the soils surrounding the lake. When so much falls in such a short time, the clay in the soil seals the surface and streams start running onto the lake. This effectively increases the catchment area of the lake and means more water ends up pooling on the surface. It is not uncommon to have monsoon type conditions later in the year, but they are certainly a few months early this year, and almost impossible to predict.

So where from here? Well, the Greenbird is now dismantled and out of the big puddle and looking for its next record opportunity, the same time, same place, next year. In the meantime, we will have the Greenbird ice craft in action in Montana in January and February.

So how do I feel? After many years of uncooperative weather I am use to it by now, but it does not make it any the less frustrating. Almost every other sport or race has direct competitors, where it does not matter what the conditions are, they are the same for everybody and all you have to do is beat your rivals and there is always a winner.
In our situation, we have to wait to get the same (or near) conditions as the current record holders had in 1999 before we even have an opportunity to compete and this makes it incredibly difficult. When we can’t set a new record due to the weather, it is not like losing a race, but it is more like an athlete not even being allowed to enter the arena, let alone get on the starting blocks.

All we can do is maximise our chances of getting favourable winds by longer standby periods and looking at all possible venues. Persistence will always win.

Here’s our final video for this season from Lake Lefroy.