X-Mozilla-Keys:                                                                                 

joa wrote:

Speaking of PSRU options I called a fellow in WA who runs Aero Kinetics

(his

name escapes me right now) and for some strange reason he won't sell one

of

his units for rotaries.  His reason being that he doesn't have any
experience with them.   All the better since his price is a little high

for

what you get (you have to finish assembling the unit by cleaning and
deburring everything plus adding the chain, seals and bearings.)  All

this

and you end up spending about $2800 by the time you're done.

>From what he said Tracy Crook was trying out one of his units but lost

it in

a flood.  Would be interesting to hear his thoughts on it though (hint

hint

Tracy :)

Joa
______________________
PIW Engraving and Milling
      "Affordable CNC"
______________________

I do have an evaluation PSRU from Aero Kinetics and was planning to do a 50
hour (test stand) run on it.  I  put about 4 hours on it when one of the
prop bolts snapped off.  The hub on this unit was not equipped with drive
lugs (just 3/8 " threaded holes).  I stopped testing until I could get
around to machining the hub for drive lugs.  Then the flood came and held
things up.   Then I got very busy on my own stuff.  I will get back to the
chain drive test one of these days.

The design is basically good.  My only complaints were the plate & spacer
adapter using only small tubular spacers that gives it very little torsional
rigidity and the input shaft made of relatively soft material.  The shaft
did not fail on this unit but some Subaru units in the field did.  Aero
Kinetics fixed these for the customers.  These are fixable problems.

Some people see the 4" offset  and shorter length of this drive as an
advantage.  It may be in some airplanes but not mine.  IMHO, there is no CG
problem when installing the 13B with "Ross length" redrive in place of a
Lyc. O - 320.  I just do not see where the 13B weighs any less.   Even if a
builder did want to mount the engine farther forward, there is nothing wrong
with extending the prop out a bit further.  In fact, the further out front
of the cowl it is, the better the prop efficiency will be.   Add a short
collar on the cowl around the redrive where it extends out if you want to
use an existing cowl.   They don't use those 12" prop spacers on racing
planes just for looks, ya'know.  :-)

Tracy Crook
rws@altavista.net
www.rotaryaviation.com

I agree with Tracy. Offset is a drawback with most cowls.
You want that engine up high so you have room under the engine for
one big rad. A planetary gear box is the way to go for most
13B engines and single engine three rotors for that matter.
Besides most belt drives are heavier than the typical  30-35 pounds
found in Ford C6 based planetary gear boxes. 

Most of my messages on belt PSRU's is for the counter rotating
Reno Racer using two, three rotor engines. I can't see
anybody coming up with a counter rotating  gear box that would accept
input from two engine and that would do it as cheap and as quickly 
as a couple of ten inch wide belts.

Paul Lamar

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