Here is the latest with the new dimensions. Still needs some minor
   tweeks here and there.

   Paul Lamar


  Paul what is the plan to split the cowl [vertically or
  horizontally? Connection type?

  Are we just making a foam buck over which Mark is going to lay up
  glass and then
  hack out the foam?

  Jarrett

  I think it is best to split it horizontally for service reasons.

  The foam buck however could be split vertically as then you would
  have a mirror image. I can do the 3D either way.

  ops I forgot to answer the connection type.
  The bent piano hinge trick is popular.
  The top is held together with a piano hinge.
  You remove the wire to separate them.

  Paul Lamar


  Alrighty, we can split it either way.. I imagine it would be
  shorter if
  we split it vertically thru the
  spinner? I'm still a little limted in 'Z' depth so the shorter
  it is in this dim the best..

  Interior ducting can easily be done either as a buck or a female
  buck/mold. Either will take a little
  to finish as they wouldn't be true 'mold's [as in waxable..] Mind
  you I can do that as well..just
  takes more time and some more exotic materials..

  It's been a few years since I used Rhino.. does it have zebra
  curves to check the surface smoothness,
  and blends across joints [curvature continous curves across joint
  lines]?
  I'll have to send some pic's of parts I've made like this on
  the mill...  did a world record setting kayak
  two years ago...

  Jarrett

  I think we can use insulation foam and cover it with saran wrap
  and scotch tape.
  The imperfections would be easy to sand off the buck.

  The short way would be a horizontal split as the total cowl
  is only 31 inches high while it is 46 inches wide.

  No zebra curves as far as I know but people tell me it will load into
  Solid Works.

  You do the whole thing and then split it on a plain.


  Paul Lamar

  Sure Paul, I can give it a whirl... can I get you to send me what you've
  got so far [model or dim's] and I'll play w/ it from there? Your correct,
  Sw can open Rhino files directly if you want to go that route.

  Jarrett

  I need to do some more tweeking.


  Paul Lamar

  Paul,

  The tunnel on the firewall has straight sides.  The roof is streamlined to
  encourage airflow through the tunnel.  The cowl portion is basically a
  half-circle, as shown in these pictures of an ES cowl (not mine).  I feel
  that my installation would benefit from slightly larger tunnels than these
  in order to improve exit airflow.

  Mark S.

  What is the thinking on these? Theory?

  It is not obvious to me.

  Paul Lamar


  That's how the heated air gets out of the cowl.  It is also normally where
  the exhaust exits.  The attached picture shows the two tunnels and the
 cowl
  flap of my current design.

  Mark

  Nice picture Mark. Do you have a large radius on the lower edge of the
  firewall just above the flap?

  Paul Lamar

 Paul,

 No, I didn't at first, but I did add one later.  Every little bit helps.
 I'll see if I can get a picture of it for you.  It is basically a thin
 piece
 of aluminum bent into the shape of an upside down question mark and
 attached
 to the lower firewall lip.

 Next, I would like to add sides to the cowl flap.

 Mark

 That sounds OK.

 I think I figured out the reason for those two tunnels.
 It is an attempt at dual augmenters... AKA exhaust ejectors.
 Since the AC engine has dual exhaust it makes sense to try
 to do this. In our case there is just not enough room IMHO.

 Paul Lamar


Paul,

I'm not so sure about that.  Most of the Lancair guys run the exhaust pipes
out through the exit holes far enough so that the exhaust doesn't soil the
belly.  I think the tunnels are there to help scavange the heated air out of
the cowl at an angle close to the relative airflow across the lower fuse.

Mark S.

Well then they should :)

Check out an early Cessna 310 it has real augmenters. I have a picture around here
someplace. Of course in the ES one would have to have SS tubes in there
to keep the composite from melting.

I like the side flaps idea. One on each side or just one on the right
behind the rad. Six inches wide by about 20 or 25 inches high.

Paul Lamar