Re: [ULF-1] florida or usa builders.

From: Member 72
Date: 2012-10-27 18:24 UTC-04:00
Message: #0405
Hi Member 62,

All good points.  We were also concerned about the aileron control cable carry through holes on each of the wing ribs.  We decided to make the holes as small as possible and insert thin walled fiberglass tubes epoxied in with T-88.  These may need thin plywood doublers on each side.  We plan to do another load test with these on a rib to see what will be needed to prevent these holes from being a weak point on the rib.  We are also planning to cover the airframe with Oratex UL 600 from Oracover.  Because each foam rib has a 3/32" thick capstrip on each edge, this should provide enough insulation to prevent any damage to the foam when we apply the heat to attach the fabric.

Member 67

  
---- Member 62 <[email]> wrote: 
> Hi,
> 
> Thanks for posting these photos, and the testing you have done.
> 
> I have a couple of slight worries about the testing - but I have no 
> knowledge of working with this foam, so they may well be nothing ...
> 
> The sample ribs that you show being tested do not have the required 
> holes for the control wires to pass through.  Would the addition of 
> these holes close to the spar attachment have a significant effect on 
> the strength at this crucial point ?  The other point is probably 
> already taken into consideration, but the method of attaching and 
> shrinking the fabric covering is not going to weaken the foam is it ?  I 
> presume that there is already a body of experience of covering 
> foam-ribbed wings, so this should be a non-issue I hope.
> 
> Sorry if you have covered these points.  My lack of experience in 
> building tends to make me wary of deviating from specified designs - but 
> I would have thought that if the ribs are as strong and light as your 
> testing shows, then you may be able to sell rib-sets to other builders.  
> It would be a major time-saver, and could prove popular.
> 
> Keep us posted !
> 
> Member 62
> 
> On [phone]:47, [email] wrote:
> > Alex,
> >
> > I forgot to attach the load test photos on my last email to you.  Here they are!
> >
> > Member 67
> >
> >
> <Snip>
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