I'm still not sure what data you are in need of here George.  I've sent the
adapter plate drawing a couple of times (same one Paul published here many
times).  If it is the hole pattern for the gear housing you need, it is a 12
hole circle (1/4" holes) with a 5.875" diameter.  I use nuts on the back
side as Paul said. You may have to use nut plates since the bellhousing does
not give good access to the back side.

Tracy

I am planing on cutting a bunch of 2.5 inch holes were possible to cut the weight.

Paul Lamar

Paul, Have you considered using liquid honing or chemical etching to bring down the weight of the bell housing? With proper
masking to protect those areas where as cast thickness is required you can then etch the web areas where the material is overly
thick. Years ago I worked for the company that was milling the landing gear doors for the F-15. They fought the weight spec on
the part until they had it down to nominal and near minus tolerance limits and could barely make weight. McDonnell Douglas took
that part and liquid honed off two pounds while maintaining drawing tolerances. Many years later I did ultra sonic inspection on
chem etched panels for Boeing. They could control the process so well they could hold +/-.002". It would probably be a toss up
for expense of either the hand work required for liquid honing or the time to mask the areas for chem etch. Casting porosity
might make liquid honing the more viable of the two though.

Rick Girard

That is a good idea Rick. A lot of this bell housing is over designed because of casting
thickness limitations.

Paul Lamar
 
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