Originally Posted by Stupot46

Kent,carbon rod/strip would be simple to do,but wouldn't I need some sort of taper?

The EPP slope guys would suggest no.

Kent

Stuart,
Just to build on Kent's idea, why not taper the number of pultrusions? - 1 all the way to the tip, 1 half way out, 1 to quarter semi-span - that sort of thing would work. You mention needing strips longer than 1m; do you need to take the spar all the way to the tip? Probably not... Especially if you're only talking about finishing it a few inches shy of the tip.
Richard

Sooo......if I used say 1.5mm rod(I'm looking at the XVIII wing here)would I lay these side by side,top and bottom?Seems to me that would be strong enough with the skin.
Maybe a single length on the Colibri style wing?
Kent,that is one BUSY forum!I did a search on it for carbon spars,loads of results which I have only skimmed the surface of.You don't have a link to the relevant info by any chance?Carbon ribbon gets quite a few mentions,any thoughts on it's use?
A more immediate problem is foam supply.Called Knauf this a/m looking for a stockist of 1200x600x52.5 30kg board to be told they no longer make the stuff.It has been replaced by 60mm which Wickes etc aren't going to be stocking.Warrens do 30 kg in 50mm which would be ok,just makes life awkward if I try to use two thicknesses in the same build.The search continues.
Thanks again for the advice,
Regards Stuart

Have you tried Sheffield Insulations? The nearest, I think, would be the branch on Sheffield Parkway. They are IIRC Dow stockists so you can get the blue stuff rather than the peach coloured stuff. Far more suitable for a chap's aeroplane...

Originally Posted by Shedofdread

Have you tried Sheffield Insulations? The nearest, I think, would be the branch on Sheffield Parkway. They are IIRC Dow stockists so you can get the blue stuff rather than the peach coloured stuff. Far more suitable for a chap's aeroplane...

Thanks Richard,on the list.Current favourite is encon in Leeds.They list Knauf 30k space board,hopefully they'll have some.I just need a couple of sheets to do this build and then I can change to a different spec.
Anyway I like Peach.Shows off my complexion.
Stuart
This is an interesting one- www.kbpackagingandinsulation.co.uk.Looks like they do hot wire cutting,I'll have to send in a mole.

Originally Posted by Stupot46

Kent,that is one BUSY forum!I did a search

I may have sent you astray
Check this link
Flat carbon starts out at about 1/32" thick.

Kent

Originally Posted by Stupot46

Kent,carbon rod/strip would be simple to do,but wouldn't I need some sort of taper?(going on the TLAR principle )
Stuart

Tapered CF laminates (strips):

http://www.cstsales.com/carbon_Laminates_tapered.html

Dr. Drela's sailplane designs use these for wing spar caps.

Kevin

Thanks Kent.I've ordered 10x1m lengths of 1.5mm rod off eBay at about half lhs price,so I'll go with that on this one.I still like Verns tow either side of the hinge line;this is all preparation,plenty time to consider options.Once I get the foam sorted it'll be back to the VII
Regards Stuart

Originally Posted by kcaldwel

Tapered CF laminates (strips):

http://www.cstsales.com/carbon_Laminates_tapered.html

Dr. Drela's sailplane designs use these for wing spar caps.

Kevin

Thanks for that K,I'll have a search for similar this side of the pond.they would be ideal,not bad prices either.
Regards Stuart

Found Some Foam!!!!!
2@2400x600x65 30kg £27.50 plus vat.Encon in Leeds,so not far to travel.
PEACHY!
Stuart

I had to pick up some electrical gear today,so I added a dimmer switch to
the order.
The set up works ok,next I need to try some different wire gauges.A trial with the tapered wire idea is also on the list.
I also need a small one handed bow,the one I have (700 mm) is a bit unwieldy for smaller work.
Stuart

I also use a dimmer switch to vary voltage on my home brew hot wire set up. Can fine adjust for any length wire.

Kent

Originally Posted by Knoll53

I also use a dimmer switch to vary voltage on my home brew hot wire set up. Can fine adjust for any length wire.

Kent

You don't happen to know the gauge and type of wire you use?Mine is nichrome,but I've had it so long I've forgotten the gauge
Regards Stuart

I use soft stainless steel aircraft safety wire. .020" dia. No complaints.

Kent

Thanks Kent.I've ordered some 0.5mm soft s/s,equivalent size.Loco1 used .3 for his taper so this should be ok for that.
Regards Stuart
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