Hi Bob
I agree that the angle of shoulder harness when attached as per manual is
less than desirable.
Keep in mind that when those attachments are called upon for integrity,
there could be two "large" passengers doing the tugging, and it may not
just be forward loads, could be negative, and or side loaded. As far as
the attachments go, forward tugging will not only try tearing out with
forward loading, but downward loading as well.
I ground some numbers and did a reasonable amount of destructive testing
and came up with what I feel has a good chance of doing what I think a
shoulder should do if called upon:
See Rollbar/Shoulder Harness in two albums:
http://www.europaowners.org/modules.php?set_albumName=Begin-06-2003&op=modload&name=gallery&file=index&include=view_album.php
Lets just do a simple calculation, take a 200lb pilot, lets say 1/2 the
weight is on shoulder harness and take a 10 G stop, that's 2000lbs, now if
the shoulder harness was pulling at a 45 degree angle (that it shouldn't
be doing, recommended is 30 positive and 5 negative), that's pulling on
attachment point 4000lbs. Will your attachment be able to withstand 2
tons?
I forget the exact numbers I used, but did research quite a bit to come up
with them and will provide if required. My simple calculation may be quite
a bit off, I forget the details, but there is a good chance that it is not
50% off.
If for the most part the loads are going to be in the forward direction,
UNI is a good choice for majority of frontal loading.
We took advantage of the aft door sill which when reinforced is a very
strong structure.
Ron Parigoris
BTW I think it's Steve Crimms Europa (now sold, forget Builder's name) has
a metal plate glassed in place, I think similar to what you propose.
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