Tracy built a mount with no offset (as did I based on Tracy's input).
Which is not the same as what your talking about. The stock mount

for my

RV

has offset going the wrong way for the Mazda/RD1 combo. I cant imagine

that

this wouldnt be noticeable so have to believe that the new front

housing

would at the least need to compensate to get everything back to a zero
thrust angle.

  I imagine $2000 - $3000 would be too much for most folks since it is
possible to have a custom mount welded up for far less. I'd think that
$1000 - $1500 would be marketable.

Mike Wills

This would be no problem at all if Tracy went to the 2.85:1 PSRU.
Prop rotates in right direction.

Paul Lamar

This would be a good point for me to get input on interest on the 2.85 : 1
drive.

It is now apparent that the RX-8 and the Renesis engine are actually going
to arrive so I've moved ahead on plans for the 2.85 drive.   I consider

this

the main reason for using the higher ratio.  I'll be ready to cut metal on
the prototype after getting the next batch of 2.18 drives done.

Opinions vary on this but here is mine:  Unless you are swinging a long

prop

(at least 75" or more) or plan to run your engine at 7000 rpm or higher, I
still think the 2.18 : 1 drive is the best compromise.  This is especially
true if your airplane is in the 200 mph or more range.  The only exception
to this may be gyros or other low speed aircraft where very wide chord or
multi-blade (4 or more) props can be used.

You don't have to commit to buy now but I'd like to get a reading on how
much interest there is in this ratio.

Tracy Crook
tcrook@rotaryaviation.com
www.rotaryaviation.com

What ever turns you on Tracy :-)

IMHO the current engine can also benefit from the 2.85:1 ratio with
the current diameter props. There is nothing fundamentally different
about the structure of a  Renesis engine that somehow makes it
better for 7000 RPM. 9000 RPM no question about it...it's better!

I'm already on the list for Tracy's 2.85 (double check that Tracy).  My 13B
is rigged for those RPM, I figure a 6000 rpm cruise and 8500 full on with a
three or four blade fixed pitch prop (LAEV when it's ready).  This should
make for an easy 175 kias cruise in the RV-4 and 210-ish flat out.

Personally I like the idea of an easy cruise turning the prop at 1900
running 160 kts.

Mike McGee, RV-4 N996RV, O320-E2G, Hillsboro, OR
13B in gestation mode

 
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