Larry Childs has agreed to produce a new bell housing at reasonable
cost in his NC machine shop if there is a demand. It can be retro fitted
to most
existing aircraft for a more professional look. It is based on Al
Gietzen's
brilliant idea of mounting the starter using the Mazda stock bolt
positions
on the cool side of the engine. Last jpg.
Weight will be low as Larry can take weight out in the final
NC machining step. Jarrett Johnson did the Solid Works design.
This greatly simplified the bell housing design and lowered the cost.
We have been trying to get this done for the last 8 years or so.
Finally looks like it is going to happen. If you order a new gear box
from Tracy ask about deleting the adapter plate, spacers and long 10 mm
bolts. Use this bell housing instead. I am sure Larry would be
glad to wholesale them to Tracy if Tracy wanted them.
Larry needs to know how many would be interested. If you want one
please let us know.
If Tracy trusts it enough to source it, I'll buy it from Tracy when I
pick up the PSRU. Tracy is a practical [electronic] engineer.
Larry Childs needs to talk to Tracy and get him to package it with the
PSRU - that would go a long way towards getting everyone to accept his
bellhousing without the typical wait-n-see approach.
Just my opinion. (And my suggestion.)
--
Vince Orton
Good luck :)
Paul Lamar
I think Vince's opinion (and suggestion) is right on the money. It appears
to me Tracy has made this part of his redrive beefy to handle expected loads
with a good margin of safety. His adaptor plate mounts with (6) bolts to
the engine whereas I can only see (4) bolt holes in Larry's bell housing
drawings. If Tracy were to give his blessing to the design, I would
definetely prefer it to the plate. I also like the idea of
inspection/cooling holes as long as the structure is not weakened.. Just my
$.02.
Alex Rose
Angle iron is beefy too but I would not use it in an aircraft.
No there are six bolts in the new design. You are missing the fact
that the starter bolts go all the way through to the end housing.
That was the Al Gietzen contribution. Actually seven bolts for 3rd gen,
Cosmo, 20B and RX8 end housings. Good design is more than just beefy.
Good design is high strenght to weight ratio. Tracy design is not
what I would call a high strength to weight ratio design. It looks
like and is a crude home made device. Most real mechanical engineers
would agree with me I think. Actually any sand cast bell housing near the same
weight is going to be stronger as the load paths are shorter. High pressure
die cast bell housings are twice as deep and weigh the same. I would love
to make them high pressure die cast but I don't think you want to pay
for the $100,000 and up tooling.
Good luck :)
--
Paul Lamar ...No rotor no motor.
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