wrote:=20 While we are on the subject of props I want to bring to the groups attention we are installing a constant=20 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=20 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 ------=_NextPart_000_000F_01C72344.5D5DDFD0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Bill,

Tracy considered doing that at one point. I = believe when=20 he realized most Hydraulic controlled props required much higher oil=20 pressure than the 60-70 psi our oil system produces, he = decided he=20 didn't want to have to produce a Prop controller to provide the required = oil=20 pressure.

Here is a excerpt from the MT propeller site = regarding=20 hydraulic pressure typically required.

The servo pressure necessary for changing pitch is = generated by a gear pump located inside the propeller=20 governor, which increases the oil pressure supplied by = the=20 engine by factor 6 or = higher.

----- Original Message -----
From:=20 WRJJRS@aol.com
To: Rotary motors in = aircraft

Sent: Monday, December 18, 2006 = 11:46=20 PM

Subject: [FlyRotary] Re: = hydraulic=20 constant speed prop for rotarys

Dave, if you go with a Mistral PSRU you can run any Hyd/CS you = want. I'm=20 supprised Tracy hasn't gone to a hollow shaft on his PSRU since he = runs a big=20 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=20 cream but not telling us which store.. :-)

Dave Leonard

On 12/18/06, lou=20 rubin <grdflyguy@yahoo.com> = wrote:=20
While=20 we are on the subject of props I want to bring
to the groups = attention=20 we are installing a constant
speed hydraulic prop on a SA2 hub = with=20 Tracys 2.17 RD
The prop is very similar to MT design except its = about
half the price & actuated hydraulically instead=20 of
electrically. Im the past we havnt had any other CS
prop = options=20 except the electric because we dont
incorporate a hollow = crankshaft as=20 our Lycoming &
Continental cousins . We are mounting the = prop on=20 a
20B in a Lancair ES however,  it could be just = as
easily=20 installed on a 13B as well We will keep you
posted on our=20 progress

We will be selling our IVO Magnum if there is=20 anyone
interested & possibly the  2.17 RD in the=20 = future

Lou  N117ES

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