Paul,
I am in the process of designing my motor mount and heat exchange locations
for my KIS Cruiser. I have been following your design, and am incorporating
several features, but have a couple of changes to suit my situation. Your
installation is very tidy, but I am not going turbo, and I would prefer to
have the exhaust go out the bottom of the cowl. I worry about CO seeping in
through the door seals. If the plane were pressurized, like most turbo-prop
planes, I would worry less.
1. I really like the "tripod" off of the firewall and the wide spacing,
however I still have some doubts about hanging it off the PSRU plate, inlight
of Tracy's statement regarding warrantee.
2. Early in the newsletter you had a design with a tube through the oil pan
as the mount. And several builders have used a plate between the oilpan and
the block, attaching rigidly to the plate. (seems like the plate will get
pretty warm for the rubber shock mounts).
Anyway, in the attached drawing "motor_mount_wws.dxf" I show a dual tripod
similar to what you had (just shorter), and I have also included a couple of
photos of a mockup using some wooden sticks and dowels. The basic concept is
to combine your "off the psru plate" using tripods, with your "through the
oil pan" (but not actually going through the pan). I am proposing a
U-channel of 1/2" aluminum, with the center section milled out to go across
the front of the engine, catching the oil pan screws -- this channel bridges
between the two tripods holding the Barry mounts. This will place the main
motor mount closer to the CG of the engine PSRU/prop .
Some questions:
1. I believe that I would want to make the two lower tubes of the tripod from
3/4" 0.049 wall 4130 tubing, and the upper tube could be 5/8" 0.049 wall
since it is in tension. I would appreciate your comments.
2. On the 1.5" diameter cups at the end of the tripod, what wall thickness
and what is the washer thickness that you used for that part.
3. I am planning on 1/8" flat bearing surface on the firewall, probably using
a conventional single bolt at each mount. Planning on a AN-5 bolt through
the firewall, is that big enough?
4. I haven't decided on the rear mount. You are using a single arm from the
top of the firewall, but I am confused how that works to prevent side-to-side
motion. The other two mount points are properly trianulated, and why don't I
need a trianulated point in the rear?
(three files attached, Motor_mount_wws.dxf, P2040004.jpg , and P2040006.jpg
<== pink foam a mock up of oil heat exchanger.
Appreciate your comments and suggestions.
Bill Schertz
KIS Cruiser #4045
Bill I was unable to read the DXF. Everything else looks fine. Where does
the water rad go? There is no need to locate the engine laterally at the rear.
The rubber bushings handle that at the front.
Paul Lamar
The AirCraft Rotary Engine NewsLetter. Powered by Linux.
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