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Old Oct 07, 2012, 05:59 AM
I don't like your altitude
Stupot46's Avatar
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Plates cut and fitted.
Unfortunately I am going to have to re-cut the roots;these were made out of two separate pieces of foam and one is about .75mm thinner.So two more out of the same piece,and I'll cut and drill all the slots and holes in the full blank before cutting out the profiles.
Stuart
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Old Oct 07, 2012, 02:07 PM
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Seems a great pity to repeat your accurate work Stuart,any possibility of applying a skin of resin on the thinner one and then sand down to get a matching pair?

Trev
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Old Oct 07, 2012, 03:11 PM
I don't like your altitude
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Quote:
Originally Posted by Crozzie View Post
Seems a great pity to repeat your accurate work Stuart,any possibility of applying a skin of resin on the thinner one and then sand down to get a matching pair?

Trev
I'd considered doing that Trev,but I don't think manual sanding will give me the accuracy I'm looking for.No big deal,I've plenty of foam to play with
Regards Stuart
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Old Oct 07, 2012, 05:17 PM
Herk
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Virginia USA
Joined Jun 2007
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I don't know Stuart --

I think of the ancient Chinese sage who said:

"Were I to achieve perfection, my book would never be finished."

Just kidding man - carry on ------
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Old Oct 08, 2012, 02:16 AM
I don't like your altitude
Stupot46's Avatar
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Quote:
Originally Posted by HerkS View Post
I don't know Stuart --

I think of the ancient Chinese sage who said:

"Were I to achieve perfection, my book would never be finished."

Just kidding man - carry on ------
Confucius he say "Wing with uneven root only swing one way"
Regards Stuart
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Old Oct 10, 2012, 06:13 AM
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In response to your post on Curvy Bird thread I agree that the t/e is the bigger difficulty, I came to the conclusion that the glove would best be 'split for the last couple of inches at the t/e to accomodate the swing portion and some local reshaping of both glove and wing airfoil to minimise the gap variation when wing swings. For the gap seal I tried some of the velour strip that is used on sliding windows/conservatory doors, as it's not too thick and only about 1'4" wide but it still needs quite a big model so that the glove is not out of proportion (and I could get it free from scrap windows!). The l/e is much easier to deal with with a radius on the swing bit centred on the pivot point which in my case was around 20% chord.
Hey! this has got the juices flowing again, maybe I'll have to reschedule my 'to do list' yet again. So many ideas--------so little time

Trev
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Old Oct 10, 2012, 06:41 AM
I don't like your altitude
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New templates cut and roots hot-wired.I made the templates out of some more laminate as they were also used as jigs for drilling.The bit I have is too short to go right through so I had to drill from both sides,worked out remarkably well.Next is to use the templates again to drill a series of holes for the radial slots.
Stuart
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Old Oct 10, 2012, 07:25 AM
I don't like your altitude
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Trev I like the door strip idea,filed away.
When I glass these things I hope to do them both together using F clamps and some worktop offcuts.What's exercising the grey matter is how these small pieces will stand up to compression.Doesn't seem to be a problem with wings,maybe because of the beds.Though I seem to recall Richard pointing out the possibility of crushing thinner sections.I think a trial press with the scrap ones is needed.
Stuart
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Old Oct 10, 2012, 07:47 AM
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To prevent crushing, instead of using clamps where it would be virtually impossible to apply absolutely equal loads to all clamps, I think that I would set the glued assemblies on a firm flat surface, place a pressure plate above withseveral precise distance pieces( which are just a few thou less than the thickness of your assemblies) in between the two plates , and stick some weights on top. This way you would not crush or distort anything and the adhesive film should also be very uniform.

Trev
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Old Oct 11, 2012, 02:20 PM
I don't like your altitude
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Meanwhile,back at the bench......Slots drilled and cut.Some of these jobs would be a lot harder without the stand drill.
Roots pinned back in their blanks and set up to cut the box slots.I did them together this time,which has the advantage of fewer nail holes in the roots.
Similar set up for the connecting arms,remembering to reverse one!
And the final act for today,placed on the base board.
Stuart
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Old Oct 12, 2012, 07:49 AM
Herk
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Not much to say but paying very close attention here ---
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Old Oct 13, 2012, 04:02 AM
I don't like your altitude
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Hi Herks.Don't get too close with that attention thing,you'll be spotting all my errors!
As the cutter I used cut a loose fit,I've been pondering how to fix the pivots accurately.What I did was put the tubes in place,apply a few drops of thick c/a and quickly fix the top plates.When this had set,I made a foam dam around the top and filled it with epoxy.When this set I turned them over,cut a slight well around the other end and also pushed a cocktail stick down to make channels around the tube.Seems to be ok,both roots turn freely.
Trial glassing next!
Stuart
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Old Oct 13, 2012, 10:38 AM
I don't like your altitude
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Some balsa packings cut,ready to epoxy the boxes and arms in place.
With hindsight I should have left the cutting of the slots until I'd glassed the surface,I now need to either blank them off or fill them with scrap to stop the resin getting in.
First will be a trial on a scrap piece,so I'll experiment on that.
Stuart
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Old Oct 13, 2012, 11:56 AM
I don't like your altitude
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All fixed apart from the lower arm which is the only part on that side.
I have a can of expanding foam,so I'm going to try cutting a slot,masking it off and smearing the inside with petroleum jelly.Quick squirt of foam to fill it.What could possibly go wrong!
After a consultation with our man in the shed I'm going to try two layers of 270gm and one of the light cloth he supplied me with for the canopy.Im also going to pinhole the surface to get better adhesion
Stuart
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Old Oct 13, 2012, 12:21 PM
Deniable plausibility
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Joined Aug 2008
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Sorry, I'm not really up to speed with what's going on (a normall state of affairs... ) but is there a force trying to peel the skins off the foam? If there is, a better solution than the pinholes (this works if the pinholes go all the way through thus forming a tie between the skins) may be to bore some holes and push balsa dowel through. Epoxy sticks very well to end grain balsa therefore giving you the tie you may or may not need.

Just thinking aloud...
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