All coming together...
Tue, 9 Oct 12 11:30
Everything is coming together now and we shouldn't be far from sailing. I think we could be ready for Thursday although we don't need to rush anything.
The wing is now mounted on the boat but has not been raised yet. We are just checking all the little bits and pieces and doing all the jobs properly. The boat really does go together nicely. We learnt so much from the first boat. Considering what an impractical boat it is... it works very well. We paid a lot of attention to making things functional as we know that oneday we will most likely have to pull it apart on a wind and sand swept beach at night. You might remember that during the last session we had a beam failure and dropped the wing over the front whilst out on the course. We managed to retrieve the lot and safely disassemble it on 'speed-spot' in 30 knots of wind with a couple of tools and NO damage at all to the wing. This wasn't by chance. For an impractical boat, she's pretty practical... and therefore a great 'tool' for the job.
I realised after we had fitted the wing that I hadn't actually climbed into the boat since our return. Obviously it's a special place for me for many reasons. I have to force myself out before I wander off to another world. There's work to do.
Whilst Alex and I sorted the wing out, Ben was putting the third 'skim' on the new foil.
I hope to get the templates delivered today although I have already followed up on it twice and the guys doing it are definitely working on African time. I forget when I say I need it 'now'... that I have to say that I actually need it 'now-now'. I kid you not. Miss that detail and 'now' means whenever the hell they feel like it. My mistake I guess!!!
The new rudder will also be mounted today after the new pintels were dry fitted yesterday. It all looks great. Nice work again by FORMAPLEX in the machining. I got a bit flashy and ordered some Gold anodised Titanium bolts to attach the pintels with. They do look the business. I love titanium. It's tough, light and it doesn't corrode. They are expensive... but so is corrosion.
Helena is flying in and will arrive imminently. This means that firstly... we have to clean the container up and secondly, it's time to move into a house. Seriously, Helena does so much of the often un-glamourous stuff behind the scenes that you don't realise exactly how much until it's not there. She really keeps the Sailrocket clock ticking true and we all miss her when she isn't here. I hope that we can finally get her in the hot seat once we get up to speed. Helena has worked at the coal-face of this project from the very start and backed it all the way. She deserves it more than anyone.
So it's all go. The weather is fine and as I write this there is almost exactly 2 hours until a guy called Felix takes mankinds greatest leap and jumps out of a balloon from around 125,000 feet so check this one out... www.redbullstratos.com/live/ I've been looking forward to this one for a while. This guy does not need an excuse or explanation as to why he's doing it. Just do it well!
Considering what I wrote above... there is one little conundrum. This guy is jumping at about the same time I'm supposed to pick Helena up from the airport! Don't even think about it... she will understand;)
Cheers, Paul.
Alex
Submitted by Bruce Williamson on Thu, 10/11/2012 - 09:19.Like Alex's barnet, even better than Boris Johnson
Foil
Submitted by Bob Imhoff on Wed, 10/10/2012 - 16:09.Hi Paul,
With reference to:
"That water has to stick at bloody high speed."
Does this mean that you are using a sub-cavitation foil again? (If you mentioned it earlier, I missed it.)
As always I'm enjoying the action as it unfolds.
Cheers, Bob
REPLY... Re:Foil...
Submitted by Paul on Thu, 10/11/2012 - 09:56.Hi Bob, we discovered in all our research that the area of the foil required to be fully side ventilated let alone cavitating would be very small. So small that it could present insurmountable problems even in the small high frequency chop that we encounter on the speed course. Remember that our foil holds us down... not up! This meant that we have had to choose a foil that is too large in area to achieve the legendary 'super' cavitation/ventilation (where the vapour/air formas a bubble/cavity from the leading edge all the way past the trailing edge of the suction surface. So the upper surface of the foil will be wetted... mostly. It will require the water to stick to it well aft of the leading edge. I will leave it at that for now.
If the water was perfectly smooth on the surface then we may have been able to choose a tiny super cav/ventilated section. We may use them still in the future. We'll see how this one goes first.
Cheers, Paul.
That sanding looks quite
Submitted by USA 3257 on Tue, 10/09/2012 - 19:52.That sanding looks quite aggressive. Assuming this thing came from a cnc milled tool, why would you risk altering the shape? Perhaps I misapprehend the photo.
Reply... RE: Aggressive sanding
Submitted by Paul on Wed, 10/10/2012 - 07:47.Hi USA...
Although the moulds were Female CNC'd moulds to a high degree, there were sections of the foil around the 'transition' (which is the 90 degree bend in the foil) which required secondary 'taping' around the trailing and leading edges. This requires us to vacuum bag on 'wet' carbon fibre strips. The reason for this is that there are very high bursting loads on a foil that is loaded in this boards manner i.e. trying to straighten the bend. This is unusual as most curve boards are loaded 'inwards' and the shells of the board are compressing against each other.
Once below this transition, most of the filler you see on the LE (leading edge)will be removed once we have sanded the shape down to the CNC'd finish. The filler will show us the highs and lows. The trailing edge is taped all the way to the bottom tip so does need fairing. We use templates to double check everything.
The two shells of the foil were clamped together with one shell outside of the moulds. One shell was in the mould and the other was pressed down onto it. In the past we have simply clamped the two moulds together... but in the past this has lead to all manner of problems... some major. For starters you can't always see what's going on inside when all the excess glue is squeezing out. The big issue is that the bonding adhesive can exotherm i.e. boil and lose its structural properties. Even with the extra slow resin we have had this happen. The reason is that the heat of the cure builds up and just has nowhere to go. Once it starts... it's too late and the whole foil can be a write off. We just couldn't afford to risk it with this one. This means we had to use different means of clamping the two shells together. If this lead to any wobbles in the final product then we will find them and fix them now. The shells are very stiff and Dan was very careful so I doubt this will be the case. The fairing process will take a little time as we have to be very precise. It matters more for this foil than any other. That water has to stick at bloody high speed.
Cheers, Paul.