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Guess I did, Bill. I know the governor
has the pump to do this, its just I've not found a governor suitable for a
rotary engine. Most require a much slower rpm drive and they are
heavy!. Naturally, one could be machined, modified, etc and a place found
on a rotary - but, MY point was that Tracy was not inclined to do this
{:>). I believe he decided that since there was no ready available
governor suitable for the rotary (and he was not inclined to produce/modify one)
that there was not much point to going to the extra expense of drilling the
required hole. That was my only point.
Additionally, with his RV-4 hitting over 2000 fpm
ROC with a fix pitch wooden prop, I would surmise that he probably did see much
personal benefit from adding extra weight, incurring the additional cost of any
type of CS prop. Just my guess of course.
Ed
----- Original Message -----
Sent: Tuesday, December 19, 2006 11:18
AM
Subject: [FlyRotary] Re: hydraulic
constant speed prop for rotarys
Ed,
You missed the point on this item. The GOVERNOR has the pump to do
this, Tracy need only provide a transfer area for the pressure. He could
do a port into the bearing near the front with a circrumfrencial groove and a
through hole on the shaft under the groove. This can be on the same bearing
surface. This amounts to a small loss of bearing area but not enough to be a
problem.
Bill Jepson
-----Original Message-----
From:
eanderson@carolina.rr.com
To: flyrotary@lancaironline.net
Sent: Tue, 19
Dec 2006 5:04 AM
Subject: [FlyRotary] Re: hydraulic constant speed prop for
rotarys
Bill,
Tracy considered doing that at one point. I believe
when he realized most Hydraulic controlled props required much higher oil
pressure than the 60-70 psi our oil system produces, he decided he
didn't want to have to produce a Prop controller to provide the required oil
pressure.
Here is a excerpt from the MT propeller site regarding
hydraulic pressure typically required.
The servo pressure necessary for changing pitch is
generated by a gear pump located inside the propeller
governor, which increases the oil pressure supplied by the
engine by factor 6 or higher.
Ed
----- Original Message -----
Sent: Monday, December 18, 2006 11:46
PM
Subject: [FlyRotary] Re: hydraulic
constant speed prop for rotarys
Dave, if you go with a Mistral PSRU you can run any Hyd/CS you want.
I'm supprised Tracy hasn't gone to a hollow shaft on his PSRU since he runs
a big plain bearing he could set up a port for a CS prop.
Bill Jepson
HEY! That's like saying that the store is giving out free ice
cream but not telling us which store.. :-)
Dave Leonard
On 12/18/06, lou
rubin <grdflyguy@yahoo.com>
wrote:
While
we are on the subject of props I want to bring
to the groups
attention we are installing a constant
speed hydraulic prop on a SA2
hub with Tracys 2.17 RD
The prop is very similar to MT design except
its about
half the price & actuated hydraulically instead
of
electrically. Im the past we havnt had any other CS
prop
options except the electric because we dont
incorporate a hollow
crankshaft as our Lycoming &
Continental cousins . We are
mounting the prop on a
20B in a Lancair ES however, it
could be just as
easily installed on a 13B as well We will keep
you
posted on our progress
We will be selling our IVO Magnum
if there is anyone
interested & possibly the 2.17 RD
in the
future
Lou N117ES
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