Here is a quick and dirty cut and pasted 3D. This is looking heavier
and heavier sand cast in aluminum. I am beginning to think Don Dunbar
is on the right track.
When you figure the weight and the machining cost of this thing you
are up to a RX8 bell house cost. Here is a picture of the RX8 starter
and manual TX light weight die cast bell housing. The RX8 auto TX bell
housing is not suitable.
If I were you George I would make yours to fit the RX8 bell housing.
Sorry I did not think of all this while Butch was still here but I
just
got around to making a 3D on his new design.
Paul Lamar
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*******************
Paul;
How that ever became my suggestion escapes me, (I must have had a LOT
more than my usual glass of wine that night)....It's not my style
(Ugly)....Too heavy, and most important, it forces & handicaps the 3 & 9
o'clock users (The MAJORITY) into lugging around all this extra dead weight
for nothing.....Not to mention that it actually weakens that whole bottom of
the Bellhousing...However, George did suggest this not to long ago but I
shot him down quickly on roll-out, I even thought I hurt his feelings, but
as it turned out he still loves me :)
*** Paul - I'm afraid Butch is correct, I've played the 'Devils Advocate'
to the endth degree in every conceivable configuration and despite his
frustrations with me - he took the time to explain WHY each time. It was a
steep learning curve for me, but I appreciate his candid responses.
On the subject of Auto Bellhousings.....I agree and recognized it from
the very beginning that Don Dumbar was/is most definitely on the RIGHT
track, and licked the "Auto bellhousing are too Long for our use Syndrome",
which has beat a lot of us to the ground simply because WE were all trying
to do this by adapting whatever popular PSRU was available
(Tracy's).....Instead, Don did the unthinkable to many of us, "Design a PSRU
from SCRATCH, to take advantage of some of that nicely protected space
available inside the Bell housing and make it work, and lighter to
boot.....I give Don 10 points for this stroke of Geniusness...However the
weight is still a big factor for us to consider.....And weighs heavy on our
endeavor..Couldn't resist this intended Pun :-)
***I also agree here Don Dunbar did a great job and only time will tell if
the car bellhousing will stand -up to the stresses of Aircraft use. Whereas
Butch's design is specifically for aircraft use.
But aside from this, we're still in the same old pickle Jar Guys....IMO,
Georgie and Group is the only one preparing to run with this ball, plus
extras to boot..And he'll have a Bellhousing waiting for it...He's going to
be hard to beat in weight and quality.
But what does all this have to do with the builders out there (The
MAJORITY) who own or will soon own a Tracy ReDrive??....Do we simply tell
them buy another or a different one or you're stuck with using a plate if
they don't want to?? ......I certainly won't, that's the purpose for the
Universal Bellhousing to fill present and future needs at an affordable
price tag.... Which brings me to the subject of price, I would be totally
shocked if this Bellhousing cannot be manufactured for well under $600.00
Butch
I am worried about the weight and cost. With 5 mm cast walls it will
be heavy.
I'll know more when I do a 3D.
There is another alternative and this is to disassemble Tracy's drive
and
install the major parts in a new cast case that fits the stock RX8 die
cast bell
housing. Here is a picture of Tracy's shaft, ring gear, planet carrier
and front bearing assemble. The stock die cast bell housing where the
600 ft pound prop gyro torque is applied is much stiffer due to its
cone
like shape.
IMHO with all due respect to Tracy the warrantee issue is not that
big a deal. Anybody that can build an airplane should be able to
overhaul
the gear box. Unlike the Ross, Tracy's box is easy to disassemble.
**Paul, I made very similar suggestions, as I have been pushed in this (your
argument) direction by one of my Engineer mates. However after many
deliberations- I'm swayed toward Butch's arguments. By the time you build a
bell shaped
housing, you have to do 3 indentations for the 3 starter positions and then
need to have another housing to contain the planetary - it starts to seem a
rather useless exercise, and extra weight.
Here are pictures of Don's housings for comparison purposes.
I don't want to discourage you guys but we need to explore all the
possibility
as casting a bell housing and machining it is a lot more expensive
than
casting a gear case and machining it. Most of the later work can be
done on
a lathe and not on an NC mill. There is also a possibly of using some
of
Tracy castings and housings with the stock bell housing.
Paul Lamar
Paul,
In conclusion, I know Butch gets frustrated at my untrained suggestions, but
I for one appreciate your suggestions and I've tried to utilize or evaluate
every one of them for this project, and like I said to Butch, a last minute
brainstorm doesn't hurt to see that we have covered every possible
alternative to get the best possible outcome - for Everone.
George (down under)