Don Dunbar wrote:
Hi Paul,
I have looking to make a PSRU and was wondering if you had built a unit
to your design.
I will use the six pinion C6 and using the 2.19 ratio.
As I have all the equipment and materials at my disposal I am thinking I
have nothing to lose.
I have obtained a C6 with six pinions that is in first class order to
use to make this unit. What is the price of a new set in the US.
The 6" tube and all sizes of aluminium plate we have as offcuts in the
shipyard.
I will look at fabricating this unit including the bell housing and
starter motor.
Is the imput gear from the Ford transmission or is this a manufactured
unit.
Do you have any advise to give me on this project.
Regards Don
I don't know what a new set would cost. Tracy is charging a bunch for the
upgrade to six pinions so I would guess somewhere around $200 US.
Used four pinion parts in excellent shape are well under $50 US.
The ring gear bulkhead appears to be powdered metal. So drilling it and
machining it may be problematic. I would copy this part over in 4130
or 4340.
Paul Lamar
Tracy Crook wrote:
I would encourage anyone who has the urge to build a redrive to do it and to
share their experience here. We all learn a lot in the process because
everyone approaches it differently. Paul is correct. The price of the
planetary gear set is pretty insignificant. The six pinion sets are a
little more because they aren't usually available on the used/rebuilt market
due to their recent introduction but still quite reasonable. I am sometimes
asked if I will cut the price of my redrive if the buyer supplies their own
gears. I always answer that the price of the drive would be about the same
if the gears were free. That is not where the cost is.
The cost of the "B" (six pinion) version is more driven by volume than
increased price of the gears. The differences in the 4 & 6 planet sets
required a few details to change internal to the drive and I couldnt use the
same parts as the 4 planet version. Because of the large number of A drive
orders I was able to get volume pricing on parts and CNC machining.
Enjoy the project Don and let us know how it goes.
Tracy Crook
tcrook@rotaryaviation.com
www.rotaryaviation.com
Don, Here is a picture of a powdered metal ring gear bulkhead that Tracy
broke by hitting it with a hammer. I agree with Tracy on this. Not advisable to
drill holes in this part. Here too is an unofficial (my guess) gif more or
less of the way Tracy did it with a few of my suggestions to Tracy
for reducing the weight.
Paul Lamar
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