Forwarded from the bounce bin. Message is from
"Bob.Harrison" <ptag.dev@ukonline.co.uk>
I cannot forward the pictures.
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Hi! Nigel.
Further to your request for details of the"PFA hold-up" on my 3300 engine
mount. Herewith pictures in an attempt to describe what is being put into
question.
In the side view you will see that the top mount members don't connect to
the node but connect to the ring about 10mm short. Stbd side could have
reached the node but the port side would interfere with the alternator
bracket. However the purpose of the ring is to enable remote locations to be
collected together and so facilitate a capable frame. But the PFA are
insistent for calculations to substantiate the bending moments in the 10mm
of the ring between the node and the offending members. (although we may be
on the verge of a breakthrough on this contention).
The other problem is that the Europa Sub Frame TOP connectors actually
cantilever out forward of their vertical support by 2.67" thereby making it
likely that this portion of the sub-frame tube is suffering bending and
shear.
(This is a fact existing with all installations except those with vertical
members on the engine mount between the top feet and bottom feet thereby
ensuring that all downward shear is transferred to the supported BOTTOM
sub-frame connector.)
ST Aviation and their engineers maintain that the 3300 engine is within all
the performance perimeters of all previously "permitted to fly"
installations , and therefore it is unfair to withhold the permit for this
installation. In particular the existing permit for the Europa 2200 mount
only falls short of the 3300 mount forces at the top sub-frame by
59lbs.ins.!
Of course these items are not so important on my trike installation as they
would be on the Monowheel since the landing /gear forces on the trike are
not on this frame and therefore don't COMBINE with the engine mount forces.
Hopefully this description makes intelligent reading ? The next epistle will
hopefully put the problem "to bed" , for the trike anyway !!!!!
Regards
Bob Harrison G-PTAG
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