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stu knowles

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Posts posted by stu knowles

  1. I did some trials with white polystyrene fom cores covered with brown paper and PVA. Some local glasscloth reinforcement, all of which worked to a greater or lessor degree.

    One had 1/4 square balsa top and bottom spars let in before covering, another had carbon tow 'spars' top and bottom and another had the BP covering overlaid with 50GSM glasscloth & epoxy.  They all flew well.  From memory, the lightest had the carbon spars and just BP/PVA stressed skin.  The only balsa was the leading edge and a hinge spar.  No veneer at all

    • Like 2
  2. On my past models I have found a slight tendency for the brown paper to lift and curl away from the cut edges around the servo bay for example. Anywhere where there isn't the overlap.  I now iron a narrow strip of scrap solartex around the edges of the openings and try to wrap it around inside.    The peel back has often not shown itself for a year or so, I guess it could be that the edges are more vulnerable to absorbing damp from the atmosphere?

     

     

     

  3. I have used the PVA/BP covering on several models, large and small with (I think) very acceptable results.  I use the same basic methods as have been outlined here.  Paste the dull side, Let it 'ease' for a few minutes,  Apply to the model working both side of the wing or fus equally.  Once all covered I paint the whole thing and hang somewhere that can dry on all sides equally. any bubbles in the BP will shrink and disappear as it dries but even if it doesn't a light application of an iron will remove all trace.

     

    Lightly sand and then paste with PVA all over again.  The next sand pretty much eliminates all signs of overlap.

    I usually paint with car celly but I look forward to trying emulsion match pots.

     

    Interesting to see all the variations on a theme.  I only use BP on all sheet surfaces but a couple of years ago Ron introduced me to Laminating film which is first class on open frame.

     

    All power to everyone on here for showing the way on model building and showing that it doesn't have to cost a fortune to have a god looking model which is different to everyone elses.

     

     

    • Like 4
  4. Apologies, I've looked more closelyand seen your light bowl plug.  Very clever!

     

    The CG on yours looks to be in a reasonably conventional position.  I seem to remember Chris Golds publishing his plan and in the write up it was much much further back than would have been thought safe.  No arguing with how yours flies though.  It looks really good.

     

  5. Well done on the L/light bowls.  I take it that you moulded your own?  I have tried a 3D printed version of the same but it was a bit thick walled.

     

    Great build by the way, You should be very proud of the achievement.

     

    Stu K

     

    PS  A sliding canopy would look good  🙂

  6. Hrllo Geoff,

    I bult one of those, probably from the same source.  I could never get mine to take off, or ROG in parlance of the day but it flew well from a hand launch.  

    Mine flew quite a bit in the first year but hasn't been out for a long time.  Think of the dust as a sort of patina

    • Like 1
  7. For larger (70" plus) 50 gsm cloth would be the norm.  I have glassed foam cores with 80 gsm cloth over a brown paper/pva covered foam core and no veneer.  It worked on a simple wing without wheel wells and would have doubed up as a cricket bat on days when it was too windy to fly.

     

    You don't have to cover the whole wing in the same cloth.  Perhaps 50 gsm overal with heavier or doubled up over the centre section and wheel wells.

     

    I have also experimented with a carbon tow laid under the glass, top and bottom in lieu of spars and that seemed to work very well for no weight at all

  8. This idea of 'Booking fees' and 'Admin Fees' are a con that seem to be catching on all over.  If they are not optional then they should be included in the ticket price.  I see that some car sales are including admin fees now.  Its a while since I bought a new car but I'm sure that my own admin fees will be equal to theirs so we can either forget them or I shall be walking out of the door!

     

    • Like 3
  9. The struts on a Pupp' are largey decorative.  Fix the wings at the centre section.  Check and rectify any warps with a bit of heat and a twist and then make the struts fit the gap.

     

    Unless you have a car that will take it in one piece, make the struts quick fix, don't use nuts and bolts as per plan.  It takes for too long to rig and de rig which completely destroys the pleasure of what is the best by far of all the Flair Scouts.  Been there and done that.

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