Hi Guys,

  Can anybody help me with engine mount drawings for the Vision, or are
  there other aircraft mounts that would be suitable?

  Attached is a drawing, sorry not CAD drawn, of the layout.

  I'm planning to use a turbo 13B engine but without the turbo. I'm also
  planning on using Tracy's PSRU. I know the engine might be overkill but
  I already have two 13B turbo engines and I'm sold on the reliability
  etc. I'm thinking of moving the wings forward, with the designers input
  and permission, to compensate for the extra weight. According to the
  designer I may also drop the thrust line to about 1" below the
  horizontal centre line if need be.

  Should I stick to the normal 13B intake or should I go the P Port route?
  If I use the correct size radiator and a larger oil pan, is it necessary
  to route the water through the oil sump as suggested by Tracy.

  I'd also appreciate any suggestions on cowling layout. I'm a trained
  artisan (Electrical fitter) but I'm no designer.


  A lot of questions but I know you guys have all the answers!


  Regards,


  Pierre Swanepoel

  South Africa

  It's tight but it could be done.
  I would go the p-port route of course :)
  I moved the thrust line down one inch.
  Routing the water through the oil pan is not effective.

  Paul Lamar


  Hi,

  Can you help me with measurements on the engine mounting and what gauge
  tubing?

  Regards,

  Pierre


  Sure no problem. I forgot to mention you need to move those
  hard point up and out closer to the skin. The loads on the tubes
  are way too high with the original design. The load MUST go into
  the skins anyway.

  http://www.rotaryeng.net/mm-instruct.html

  Here are the dimensions on the schertz beam. There is an easier way
  of making this if you have access to an Amada  NC punch.

  Make it out of a deep channel and a flat sheet metal top. The NC punch can
  punch out the lightening holes. Weld washers under all bolt holes.

  Paul Lamar


Paul,
   Thanks for taking this on, I'm another Vision builder (or will be soon)
who will benefit from having another engine option when the mount is designed.

Pierre,
   As you know, the all-up weight of the 13B, PSRU, engine mount, intake,
carb or FI, exhaust, cooling system, and accessories will likely exceed
the allowed 300 lb FWF weight.   Some creative plumbing of the coolant
system can help get the FWF weight down a little, but at the expense of
greater overall weight and complexity.  Some builders have commented that
the 300 lb limitation is a function of the strength of the shear panel that
transfers loads from the firewall to the wing spar.  Maybe within the Vision
group we can hash this over with Steve et al and see if there's a simple way
to increase the allowable weight 50 lbs or so.  We're not trying to build
super high HP hot-rod aircraft, we just want to use a highly reliable
engine that happens to be a little heavier than 300 lbs all up.

Mark Waldron


Does anybody have a stock cowl yet?
Does anybody have a section drawing of the stock cowl?
Perhaps the manufacturer can send one if you tell them what
you are trying to do.

Well you can get some weight out of Tracy gear box with a bit
of NC milling. Maybe as much as ten pounds. Also one or more
aluminum ending housings would save about 20 pounds or a bit more.
The back housing is a good candidate as it would have more of an
effect on the CG. One of the aluminum water pump cartridge that
Steve Beckham came up with will also help. An Inconel exhaust will
also help.

Paul Lamar
-
*********************************
- I can't get to my plans right now, but IIRC there are no stock cowl
in the plans since the engine choice is left up to the builder.  The
prototype flew with an O-200 and a Subie.  As I recall, Steve Rahm
(the designer) provided instructions on carving a male cowl mold
from foam and using it to make a cowl.  At least two aircraft (Dave
Cress's and Sean Ponsonby's) have flown with O-320s.
Perhaps we can get some measurments from the cowls they made. Anyway,
at least this approach gives us lots of flexibility when designing the
engine mount, radiator placement, etc since we can design a cowl later.
- One thing that complicates the issue is that the plane was designed
for a fuselage width of 40", but nearly everyone widens it to 44".

Editorial coment: The Vision community shares some attributes with the
rotary aviaton community:  It is made much more interesting by the
degree of flexibilty, customization and true experimentation that is
available, but these same factors have historically slowed the
development and fielding of a "good enough" standardized design (or two).

Paul, thanks for the weight-saving suggestions.  I'll probably have
to limit myself to the lower-cost ones.

Mark Waldron

Well  if we are going to use a custom cowl I'll draw one and publish
the section dwgs and or the solid so Jarrett can make a mold.

One or two layers of carbon tape laid at a diagonal can beef up the
nose at little increase in weight.

Paul Lamar