Lucky we looked!
Yesterday morning, after an e-mail discussion with Malcolm regarding the new front planing surface, I decided to remove it and beef it up.
When I finally got it free from the silicon sealant I noticed that it had already began to fail. The top carbon fibre skin had buckled under compression which indicated that the planing surface had been bent upwards at some stage. It was most likely when we had broken the aft planing surface as it is probably due to going too fast in choppy water.
It still felt solid... but it was definitely on the way out.
The reason I went to the effort of removing the whole thing in the first place was because Malcolm mentioned that the only time he saw the model pitchpole was when he tried it with no front planing surface!
The build was light and deep down I wasn't happy with it. I don't want to 'hope' that something is OK. I want to know that is OK.
Helena and I rebuilt it and replaced the foam core with good ol' plywood. The carbon fibre skins were also more than doubled in strength.
It spent last night under vacuum. I wanted to get it on today but the details will take a little longer to cure.
So I'm a bit annoyed at the delay...but grateful that we found it before it found us.
Wind-wise, yesterday was a good day too.
Malcolm has sent through a number of adjustments to be made to the rig and overall setup.
The beam will be moved slightly, the rake will be reduced as will the cant. It will all be stood up a little.
So still plenty to do.
The RIB was sorted out. There was water in the fuel which required all the carbuerettors to be removed and cleaned.
We'll be back in action tomorrow.
Cheers, Paul.
Paul Larsen
Mobile: + 44 (0) 794 684 1929
E-mail: paularsen1@aol.com
www.sailrocket.com
Mobile: + 44 (0) 794 684 1929
E-mail: paularsen1@aol.com
www.sailrocket.com
posted by Paul at 11:44 am
5 Comments:
The world is watching Paul - well, at least a little bit in Gloucester, UK.
Stay steady with it.
Cheers,
John
Just another idea to make sailrocket faster (but it takes some work):
Cut away some 150cm in the midle of the mainhull and replace it by a cockpit that just not touches the water. You can place the foil below the cockpit then and skip the front foil.
And make an attachment of the beam just behind the cockpit.
This results in a much better distribution of weight and lift so you can place the foil more upright and probably can remove the extra planing surfaces.
You can probably not execute this in Namibia but it doesn't take a lot of time nor money to make such a cockpit. Maybe it's an idea once you are back in England.
The foil like it is now doesn't garanty fixation to the water as is shown recently so the current figuration is not fullproof and therefore also not 100 procent safe. And if contact is lost with a lot of lift in front and weight in the back is worse than with the beam further backwards and the pilot in the middle
Anyway, just some well ment thinking..
Cheers,
Johan
O and about the pitchpoling of the model: The model had no weight in it at all and the foil of the model is in front and inclined. Put the pilot in the middle as well as the foil and there is a much lesser chance of pitchpoling I believe even without the front planing surface.
You can try it on the model first !
1-2 kg in the middle will suffice.
Johan
Just an add:
You can make the cockpit also a bit deeper so a third planing surface is created. This creates a bit more lift so the extra (wide !) planing surfaces can surely be removed. This results in less drag I'm sure and a good base for a foil. The foil must not be placed higher than the front and back planing surface so a third planing surface in the middel at the same hight as the front and back is best I believe.
I would give it a try with the model. The rest all can remain the same so it gives improvement with relatively little effort I believe.
Cheers,
Johan
Lats add then I shut up:
You can make the main hull a bit longer this way if desired, just cut the hull in half and add the cockpit. This gives even better pitch stability but without the need for excentricly placed weight or inclined draginducing foils.
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