View Full Version : grp lay up for flow straightners

nickyd - n/a
21-Jan-08, 07:20 PM
Hi all,

Can anyone suggest a decent laminate thickness for making flow straightners and centre cone? Obviously it needs to be as light and strong as possible http://hovercraft.org.uk/images/icons/smiley_icons/icon_biggrin.gif

I'm after ideas of mat thickness and type of mat and number of layers etc.



team black - n/a
21-Jan-08, 08:01 PM
Flow straighteners: 1oz CSM/Diolen/1oz CSM. Cone 2x1oz CSM.

Why make it light? are you moving out of 503?

Jamie Lewendon - n/a
21-Jan-08, 08:07 PM
Nick, our flow straighteners are 1 layer carbon, to give a swanky finish (No Gel coat, layed up with resin gel mix) and 1 layer of diolen, this is in 2 halves. Cone is 2 layers of 1 oz CSM. Straighteners are stuck into slots, and protrude 3" in. Then sikoflexed. I then stick a disc 2 layers of CSM into the front of the cone, and sikoflex i. The whole lot is then foam filled, filling the cone, fixing the straighteners, foam fills up the flow straighteners. I then top up the straighteners from the outside.

This creates a hugely strong structure, that has been proven on several occasions.


nickyd - n/a
21-Jan-08, 08:56 PM
Thanks chaps,

What weight Diolen are you using?

Not moving yet Ewan. It's all about where you put the weight though isn' it........


team black - n/a
22-Jan-08, 07:37 AM
Diolen is about 265 gram- Keith can sell it to you or Trylon can do it, but are likely to be more expensive

tonybroad - n/a
22-Jan-08, 10:28 AM
i use a couple of layers of 1oz CSM, coloured resin (no gel)

i put expanding foam inside them whilst still in the mould to minimise any expansion/shrinkage/distortion - allow foam to vent either end

i fill the cone like jamie - stiffens the whole thing up


Keith Oakley - n/a
22-Jan-08, 06:16 PM
When you put the flow straightners in the duct remember to put them at least 100mm back from the fan. This significantly reduces the noise generated with no negative impact on airflow performance (in fact it might improve it) as shown by Paul Hibbards F1 (no 16) performance last year and I understand from Dan T is current RR practise on jet engines.