BTW George I don't understand why you don't make your PSRU the
same out side dimensions and mounting bolt pattern as Tracy's.
That would cut the cost of machining as both could use the same
NC program. Here is a sketch of what Tracy's looks like with a
few weight reduction suggestions on my part. After all you are
using the same gear set as Tracy.
Also I think Butch's scheme for mounting the lower starter won't
work. The starter pinion is about 5 mm too far out to mesh with the
ring gear. I would not start on the pattern until this is resolved.
Paul Lamar
Paul,
I am using the same gear set as Tracy's unit, the 2.85:1 Ford E4OD, 6 planet
housing.
The same bolt pattern requires long bolts through a solid housing (simple
and effective) but the narrow base of the Planetary section represents the
weakest point, a broader base enables spreading the load out further.The
flanges enable easier bolting and access, as well provides sufficient room
for sealing rings.
The machining won't be more for those who use Tracy's unit as it's machining
the inside of the built-up area (in the centre) which provides for the
raised centre section (one of your suggestions) which in turn adds strength
and ties -in the stiffening ribs on the face.
Actually one of my thoughts was that I would like to extend this flange out
further (as in the Ross) as it would suite my design better - but would add
unnecessary weight to Tracy's unit.
As a matter of fact I intend to use the inside machined area to install a
'HAT' section for, sealing the back of the planetary holding a thrust
bearing and drive shaft seal using the same bolt pattern. So in the end it
will be the same weight.
You could also mount Tracy's unit in the front of the housing if you needed
the extra length. It's just a matter of bolting on the plate at the back or
at the front (with additional spacers if needed) - another added advantage!!
Important note, this would required a longer drive shaft - but doable!
BTW I've tried not to copy Tracy's unit, it's his design - I want something
different and I've achieved that in a number of ways.It's coming together
nicely (in my head).
Another one of my ideas was that I would have liked to go to a more 'bell
shaped' bellhousing (similar to Don Dunbar's set-up) with side MM's, but I
would need to house the planetary inside - as Butch pointed-out that this
would also require additional weight. Also if a builder used Tracy's PSRU,
and adapted it to that design, it would void his warranty.
So the flat face with stiffening ribs is the most economical in weight and
production costs and meets everyone's needs.
On the 6 o'clock position, I would have preferred a section like the side
MM, but as Butch pointed -out, that would result in a need for some extra
weight to be carried by those not needing the
6 O'clock position - it might have also been in the way of the rads mounted
below the engine.
If the pinion gear is too far out that would mean the mounting flanges of
the starter are too wide to fit between the lower stiffening ribs - using
the Subaru starter would solve that problem as it has a smaller footprint,
Butch is aware of this !
Just some thoughts, which have come about from past discussions on the
bellhousing.
Everything's a compromise I'm afraid!!
George (down under)
Now if you adapt it to Tracy's PSRU you need another 1/2 inch thick
plate.
Not light weight.
I like my idea better of quite some time ago :)
It would have given you the support you need and fit Tracy's
perfectly.
Paul Lamar
The AirCraft Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/
Copyright 1998-2003 All world wide rights reserved.
