If you think there is 10 lbs to save in Tracy's PSRU, that's huge
 considering CG and all...If someone is willing to get the necessary
 components that can be whittled and you direct in the ares to be machined,
 I
 would be willing to do this for a very small sum to cover the tooling and
 possibly the fixture material, about $200.  NO other machine shop would
 touch something like this for under $1000 .................

 thanks

 jeff

 I'm interested! My psru still in the crate.
 C. Smith


 Here is another way Jeff. We rejected this idea a few years ago because of
 excessive cost. The cost on NC milling has come way down recently.

 The big weight savings is it combines the schertz beam with the adapter
 plate. A schertz beam alone weighs up to 9 pounds depending on the length.
 Bob White tested it for us in a crash.

 The right side can be much shorter to accommodate a rad on the cool side
 of
 the engine. I'll do a suggested dwg for you. It is a half inch thick.
 Jerry
 Hey tested it for deflection and Jarrett did an FEA.

 Paul


 I will have bottom Radiator, and what looks like 25.98 between barry
 centers
 if I read the drawing Paul made of the mount for me correctly.
 So combo plate, then some shaving on the housing, what, 19 lbs saved????
 8-D
 C. Smith

 Not quite that much as some goes and some stays. I would say 15 pounds is
 possible.
 We should standardize on the asymmetric mount as it can be used with a
 bottom rad or a right side side rad.

 It will look something like this. I'll have to redo that zenair dwg if we
 use this plate.


 Paul Lamar


 I think I like this method. The strength is proven in the crash test. Can
 you proceed with a new drawing for the Zenair mount?
 Jeff, can you make these if Paul sends you the cad file? Cost to produce?

 Paul, what was the depth of the cutaway for the gear housing in the image
 Tracy-PSRU-10-2000-dwg, and how thick should the flanges created be? Can
 the
 RD-1C be safely disassembled by an average skilled person?
 Jeff, with numbers from Paul, can you make the modifications to the gear
 housings? Cost to modify?
 I bought the 4130 sheet for the S-beam, but much of the cost is in the
 fabrication, so I can eat $46 in material.
 C. Smith

 The max thickness on the housing should be 1/4 inch everywhere.
 Tracy got carried away and made everything a 1/2 inch thick or thicker in
 some places.

 The Ross gear box was 5 or 10 pounds lighter.

 Tracy's older 2:17 PSRU comes apart rather easily. You take out the 10-32
 screws holding the front cover cover on and the large ball bearing should
 come right out.
 On mine Tracy glued it in with red RTV. Then you have to unbolt all the
 long
 1/4 28 screws holding the unit to the adapter plate.
 After that it should fall apart. As I recall on the 2.85:1 the ring gear
 is
 pressed and keyed into the housing so you don't need to remove that. Power
 is taken from the planet carrier. Ignore the green and red parts. Those
 are
 just my idea for a built in torque meter.

 Paul Lamar


 Jeff,

 This may or may not help you. It is looking at the adapter plate from the
 prop point of view with a dual set of dimensions. The radial set came From
 Tracy.

 BTW guys I suggest everybody get a copy of free Q-Cad as it works on both
 Windows and Linux. That way I can send you 3 view 2D dxf dwgs and you can
 dimension them yourselves if you are interested or need to make the part
 by
 hand.


 Paul Lamar


 Other wise I need to do a lot of extra work as modern 3D cad dwgs don't
 normally have dimensions on them. They are drawn to exact scale and they
 can
 be loaded into a NC Mill without anybody reading the dimensions.

 Paul Lamar


 Q-cad installed and running, but it's not really free. It terminates at 10
 minute intervals, then after 100 hrs total for good. However $35 isn't bad
 for the ability to get some stuff done and not have to take up time that
 could be better spent upgrading Kasauga mills, or designing new stuff for
 rotary aviation.
 C. Smith


 Thanks Craig. I think it is well worth the $35 for a 2D cad program.
 Seems rock solid. I'll send some dxf's for it shortly.
 In fact try this one and see if you can dimension it.

 Paul Lamar

 Paul, I bought a cad program on e-bay for $24 called  DesignCAD  3Dmax v18
 just to try out the rendering part. It does 2D drafting and 3D solid
 modeling, 3D rendering and animation and has a huge symbol library. I
seems
 easy to use with all the normal drawing commands etc.  They had about
fifty
 listings on this program recently.It has multiple import/export formats
 including dwg and dfx as well as a lot of newer ones.You own it outright,
 no
 time or save etc limitations.

 george grimes

 Does it work on that 2D dxf I just sent.

 Paul Lamar


Paul, The listed import file extensions are   DWG,DXF,IGES,WMF,HPGL,and
XYZ  . There is a setting for 2D/3D operation. I downloaded the rear
housing
dxf file and lost it  on the hardrive. I saved t twice because it showed
174
KB and saved as 22.4 KB    I will eventually capture a dxf file  on the CD
drive where I can find it and try it out

george grimes

Well Design Cad does not work on Linux so I can not try different files
in case someone has problems. Q Cad works on both. Like Office, Thunderbird
or Firefox it is a cross  platform application with complete file
compatibility.


Paul Lamar



Paul, does your Rhino run on linux. I am using XP because the programs I
find run only on windows. I got the dxf files off the last post and will
have to find something to unzip with. I bought win-zip and it is on here
somewhere. I wasn't suggesting we need a dynafocal mount, it just seems to
be less material lengths on the motor mount tubin and less engine in the way
of triangulation of the structure and might be stronger and lighter.The
radiators might be mounted to the ductwork  of the lower cowl or under the
motor mount. For side mount radiators like the zenith 801 the extra weight
of a separate frame for the radiators might end up heavier.

george grimes

No Rhino does not work on Linux. It is the only reason I still have a
Windows computer. XP HAS unzip AKA Compress. What version of XP do you have?
Zip or Compress is built into Windows Explorer that comes with XP. You do
use Windows Explorer do you not? A lot of people don't even know about
Windows Explorer let alone use it. Windows Explorer was a bad rip off of
Xtree Gold for DOS.

What you do is "send" a file to a compressed folder. That makes
a smaller file in the same folder you invoked it from. The new file than has
a .zip extension. To un zip it you choose the file and then choose
"extract all". That unzips it and expands it of course.

The reason it is a good idea to compress raw dxf files is they tend to be large
and they are merely a large collection of ASCII words readable by any text editor.
If you attach a raw dxf file to an email message they automatically appear at the end of
the  received message as a huge text file making the message pages and pages long.
It then becomes very difficult to extract the DXF part from the rest of
the email. When it is zipped and attached it always appears as a separate entity.

The other problem with a Lycoming dynafocal mount is the 570 pounds of prop
torque is transmitted back through the engine to the rubber motor mounts.
Mazda never envisioned this to happen to one of their engines. I know Mistral
uses it but they have the opportunity to redesign the rotor and end housings
to accept this level of torque. Mazda had enough trouble with the third
gen turbo engine cracking the end housings around the dowel pins designed
to transfer the front rotor torque to the rear end housing of the engine.
The Le Mans engine was beefed up to act as the last half of the race car
chassis.

0.049 thick 4130 tubing 3/4 of an inch in diameter is .0344 pounds per inch.
A 30 inch long piece therefor weighs only about 1 pound. The tubing portion
is the lightest part of the motor mount. The schertz beams probably
weighs more than all the tubing combined in most designs.

The ideal design is the Questair Venture and Beechcraft Bonanza where the bottom
of the cowl does double duty as the motor mount.

Paul Lamar