X-Mozilla-Keys:                                                                                 
Bill Freeman wrote:

JDana2@aol.com wrote:

Brian .... The purpose of aluminium end plates is to reduce weight of the
engine. The art of the design engineer is to make the plates in such a way
that the structural integrity of the engine is not compromised. I was and am
still looking for men who would like to do just such a feat. IT AIN"T EASY.
   JIM DANA

Paul,

I need to point out that aluminum has a modulus of elasticity that is
1/3 of steel/iron.  For the non-engineers, this means that physically
identical parts will deflect 3 times as much under identical loads.
This *not* a breakage or failure issue, since many alum alloys are
very *strong*.  But ALL aluminum alloys have a much lower
stiffness, therefore the engine will deflect 3 times as much unless
a geometrically stiffer design is used to recover the lost stiffness.
This is possible,but understand that aluminum isn't just
"light steel".

Also, a sobering note.   A guy from work just killed himself during
his first flight of a two-seat Fisher Horizon homebuilt.  Proximate
cause was stall-spin.  Probable underlying (not yet verified) is
either inadequate power or most likely - ground adjustable prop
set too flat, i.e. lots of low speed acceleration, couldn't accelerate
to a safe flying speed. Engine was a converted Subaru, apparently
still running at impact, but he couldn't climb out of ground effect
and attempted a turn to downwing - stall-spin, crash and burn.

Another point of interest.  I know two pilots that have (stupidly)
stall-spun old steel tube fuselage birds into the ground and one
that collected a power line which wrapped around the fuselage and
stopped the bird in flight.  All three survived with zero to medium
(broken leg) injuries.  I personally believe that the use of a steel
tube fuselage and full harness will provide *very substantial*
survival enhancement in event of a crash.  The Fisher is geodesic
wood (tiny strips criss-crossed) and it crunched up and burned.
The fire is also an issue, like where is the fuel tank??   I'm not sure
in the Fisher, but surmise it might be in the "Cub position" -
i.e. in you LAP!!!    I strongly suggest fuel in the wings.

Ya'll be careful out there.  The laws of physice will be STRICTLY
enforced!

Bill

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