Paul,

 All the X & Y dimensions are from the flat firewall.  Note there are five
 mounting points. Designer call for up to 180hp with the four point, with up
 to 260hp with five points.  I'm trying to get an idea of the room using
 either a 13B or 20B. Only one Bearhawk is flying (Elden Yates).  Little
 details, but Elden ended up putting his battery next to the PSRU to get
 some weight out on the nose!  Plan is to use Tracy Cooks PSRU. With 180hp,
 Bearhawk cruise is 140mph, with 260hp it is at 160 mph (75% on both
 numbers).  --

Tom There are five mounting points on the Bearhawk Firewall.
 Firewall is approximately 2" larger at all mounting points.  In Inches: X Y
 Lower Left 3.500 0.000 reference Lower Right 31.188 0.000 Upper Left 0.000
 20.188 Upper Right 34.688 20.188 Upper Middle 17.344 24.844 THRUST LINE
 17.344 15.844 Firewall set back at 6 degrees (top towards tail).
      Prop Flange (front
 edge) to
 VERTICAL MOUNT -
 40.625"  Note, from
 firewall (6
 degree lean back - top towards tail)
 is sin 6 *
 (Thrust Y position) or an additional
 1.656"   -- end of email ---

 Does this look right?
 Now you want me to lay it back 6 degrees?
 Paul Lamar

  Paul, The bottom measurement should be changed from 27.500 to 27.688"
 Upper middle is 24.844" from the lowest two holes.  Correct, rotate the
 firewall back 6 degrees. Point of rotation is from the lowest two points on
 the firewall.  Thank You, Tom OK Tom Here it is.  Paul Lamar
  Looks good.  Bob Barrows, the designer, doesn't have an email account!  No
 computer, either! I suspect that is why he gets so much done.  Thanks, Tom

 I'll see Bob at OSH and show him some of this stuff.  Here are some
 preliminary 3Ds. Ask questions if you see something that looks strange.
 Upper motor mount is not in yet but we will use a rubber ball jointed strut
 mount to above the water pump.  Are you using and RX8 engine? That area
 differs from the 13B.  Paul Lamar



Paul,

Looks great!

I have not purchased an engine, so still discovery stage at this
point. Plan is either a RX8 Renesas so the exhuast lives, also
looking at 20B's.

Looking at approximate weight and distance from firewall to do some
preliminary W&B -- yes numbers we want to run past Bob.

Tom

There are two details that are different 13B verses RX8 engine.
Pan bolt pattern and details of the top mount on the center
housings. Here is the 13B version. I have an RX8 engine in the hangar
so I'll get a picture of that shortly.


The distance from the firewall to the CG of engine, gear-box, prop,
starter, alternator and muffler is 23.5 inches. Weight is on the order
of 280 pounds. Plus or minus 10 pounds. You won't know exactly until
it is built but this beats a six cylinder by a long shot if you go P-port.

------------------------------------
More details and more to come.

Paul Lamar