Conference vmszoo::rc

Hi,

	Not having come across an Alumninium blind nut
I can't say for sure...but I would tend to support
the idea that it will wear..The blind nuts I have seen are
made from steel, usually supplied with nylon bolt; I,ve
had the nylon bolt sheer before and substitued a brass one
since then I have had no problems.
	Is there a specific reason for the Aly nut being
used?

-Trev

    Are you SURE you want to use metal screws to hold the wing down?
    If the wing decides to leave the fuse other than when you want it
    to, it might take a huge chunk of fuse with it.
    
    Smaller sizes of nylon bolts are available that work with metal
    blind nuts just fine.
    
    Good luck,
    
    Ron

I crashed a glider the other day. Major damage to the wing was averted when the
nylon bolts sheared off. 

md

    JIm,
    
    I would be afraid of a steel screw wearing off th aliminum threads.
    Especially when the screw is easy to replace and the nut is not.
    
    One thing I know about steel/aluminum combinations is that you'll
    always get corrosion (on the aluminum, I think) due to electrochemical
    reactions.
    
    We once had a bunch of folks at our field (where I was raised). They
    had designed a high-wing trainer with an all aluminum fuse and a very
    sturdy foam/veneer wing. They were using it for professional training
    (R/C school). The design was very robust, but after only a couple of
    hours, the fuses - built up with steel rivets - were starting to do a
    VERY loud and annoying rattling: The holes in the qaluminum plates were
    widened due to the aluminum corroding. They got rid of the problem by
    introducing aluminum rivets instead.
    
    I don't think this would be a problem if you only have the wing bolted
    to the fuse during flights, but I wanted to make you aware of the fact
    of electrochemical corrosion.
    
    Best regards,
                    Hartmut
                           

    Go with Dufresne's advice. He is the expert on breakaway wing bolts :-)
                                         

Hi,


	I can see what you mean regarding the nylon
bolt, and being easier to shear on impact. My view
though is, if you plough it in, then there's loads to 
repair anyway, and if you lightly plough it in...well
it's luck if the bolt shears or not and even having it 
shear doesn't always make the damage any less!

	At the end of the day it's your choice...
although the point about how many G's maybe worth bearing
in mind.

-Trev

When my Alcyone 2M came screaming into the baseball backstop inverted, the 
nylon bolt held and the bolt block which was fiberglassed into the fuselage 
still broke free, saving the wing undamaged.

    
    I replaced two 1/4 inch steel bolts with plastic screws on the U/C
    fixing on my trainer. I had a hard landing and wiped the U/C off, both
    screws snapped cleanly.
    
    I just wonder whether the impact would have just been absorbed by the
    steel screws, or whether they'd have torn the bottom of the plane out!
    
    My feeling is that you can't stop a plane being damaged by an impact,
    but you CAN make some efforst to decide what gets bust first!
    
    Cheers
    
    Nigel
         

I've used the same technique on my Panic undercarriage and it got me back 
into the air faster than regluing the mounting plate (which had broken out 
on other days).

Car manufacturers are starting to see the logic in this with crumple zones 
to absorb some of the energy as well.

As long as the bolt can withstand the flight loads, I'd rather put in 
something with a chance of breaking and saving part of the plane.

    For what it's worth I use steel bolts (with the allen type head) to
    hold my wing on. The blink nuts are encased in carbon fiber in the
    fuse. I use a carbon fiber plate on the bottom of the wing to
    distribute the load where the bolts go in. I have used this setup 
    for a couple of years now and never had any fuse damage etc granted
    I have never had a wing pop landing manoeuver aka wing roll etc to 
    really see what damage could be done. Before I used rubber bands and
    eventually got fed up using them. I have done this to my Acro-Wot,
    Wots-Wot and my 2 saphir's. 
    
    I guess I have been lucky. When I had my Hi-Boy trainer I used rubber
    bands on it all the time. But I found that replacing the center of the
    leading edge with a piece of hard balsa removed the inevitable dunks,
    dinks etc  that resulted from unorthodox landings.
    
    My 2 cents worth.
    
    Eric. 

    OK, what's a "BLINK NUT"?.
    
    Regards,
    
    EVL-1

    
    It's one of those nuts which closes up (blinks) as you try to start the
    bolt in it's thread. These are normally located in hard to reach
    places.
    
    8^)
    
    Nigel.
    

    I sometimes wish I hadn't opened my mouth ! 8-) 
    
    Eric.