Subject: PSRU fixes
From: rotaryeng
Date: 9/12/2012, 11:03 AM
To: AAAA Put this in the To box

Barry,

Before we go too much further, we need a PSRU  that can handle 500+hp.
We've already had flywheels [flex  plate] disintegrate and my
input shaft broke the
lock pin.  I would  consider installing a turbo, but in my opinion, the
psru is the weakest  link.

Mark
P-port 20b

My last trip to Tracy's we discussed  this. His recommendation  is to use
an aftermarket aluminum flywheel  and attach the PSRU input to that. His
latest iteration of the PSRU will  attach to this flywheel easily he says.

As far as the lock pin, that  would take more thought. Drilling it out
and installing a larger diameter  pin will increase the shear of the pin
itself but at a cost to the strength  of the shaft itself.

Kevin Alderman

Just install two lock pins  90 degrees to each other.

We did that on Dave's turbo Reno  racer.

When I get home I will send a dwg. We have been around and  around on
this. I am surprised Tracy did not mention it or start doing  it.

Paul Lamar


Other than the weight, I take it  there was no problem with the flywheel
Dave installed?
Re:  the pins: is it possible that the pins were transfering the power and
the  pin bores were tight and the spline clearance was allowing the power to
try  to flex the pins?

Dale Davies

Dave has reported no  problem so far with the steel flywheel.

BTW If you can't handle putting  two pins in the sun gear send it to me and
I
will do
it. I have done  a couple already,

Paul Lamar

Is Dave Leondard racing at Reno  again this year?
Chris Cosman

I don't think so.

Paul  Lamar


To All,
While we are addressing PRSU issue's, here is  another one. I'm
mounting my prop extension and prop; In doing so I have  found
that my prop tips move about 1". Is this too much back-lash?  Seems
like I remember hearing that it should be around 1/4". Any  suggestions
would be appreciated . Thanks!
Frank Clementi

Mine  moves about an inch as well. Next time I go to the hangar I will
measure  it.

Paul Lamar

Paul,

Tracy recently told me the backlash  should be between 3/8 and 5/8".

Mark

I'll go out today and see  what mine is.
Frank, What gear box do you have? 2.17 or 2.85?

Paul  Lamar


doesn't the amount it moves depend on the length of the blade?

What length blades are y'all using?

Rich

Yes but it is a minor factor. Most props are 68 to 72 inches in diameter.

Paul Lamar

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