Paul, could you please render a new version of the CH-640
mount(based on the ch-801, but with a lower rear attach
from oil pan rear over the nose gear strut), utilizing the
Doddridge plate, Tracey Cook RD1-C, rear lower oil pan
vibration stabilizer, etc.  (basically all the features of
the final version you sent) but move the plate and engine
out 6" further from the fire wall to accommodate for the
use of the RB light weight center and end plates?  I spoke
with Mathieu Heinz when I picked up the wings in Canada,
discussed the implications of the lighter weight
installation, and his recommendation was to move everything
out 6".

Also could you make notes for me as to the basic
raw construction materials used, like different tubing
sizes, IE diameter and wall thickness.  I have both Q-Cad
and Alibre now, so I should be able to read the cad dwgs
directly.

 Craig Smith

 snips...

 Preliminary motor mount design.

 One of the unanticipated (by me) side benefits of a light weight 200
pound
 (with PSRU & acc.) 250 HP p-port all aluminum engine moved six inches
 forward in the cowl is more room for the cooling system.

 I would also take advantage of the increased net payload by enlarging
 the fuel tanks for more range. Lots of range is a safety factor as
 you could get somewhere and need to go back because of weather.

 You will also need a 3 blade prop to absorb all this HP.

 This airplane is going to blow a lot of peoples minds.
 Excellent short field performance will be all too obvious.

 Paul Lamar


Two hundred pounds with PRSU and acc. ? Is this accurate Paul, I thought
that was an approximate weight for the light single rotors.

John


Well the bare block two rotor came out to 109 pounds.
There is a picture of Doug holding one at 7 Stock on the
front page of the web site.
I guessed at the rest. 45 pounds PSRU. 7 pounds starter
8 pounds alt., etc., etc..

Poorly educated guess :) Probably not including fluids.

------------------------------------------------------
Craig,

What do you think about bracing the cowl area with a couple
of 1/2 inch 4130 tubes to feed rear motor mount loads
back into the longerons under the gull wing doors?

Just think of it as an extension to the motor mount.

Then I can use this top rear mount scheme.

----------------------------------

Update 640 specs etc.

Paul Lamar

The only bit of information that I can seem to figure out is
different between the 801 and the 640, but has to be implied
from the drawings is that according to dwg. 20-P-1, is the 640
firewall angle is 17.5 degrees, vs the 18.5 degrees of the
CH-801 according to the dwg. THRUST.
All other hard points and dimensions are identical. I'm making
assumptions about firewall details other than the motor mount points.
C. Smith

Send both dwg's and I'll have a look.

Paul Lamar

I just called them and they said they use the same O-360 motor
mount on both the 801 and the 640. That means the firewall angle
is the same. They also have no objections to the reestablishing
the fifth upper mount using the two 1/2 OD 4130 tubes.

I told them I would send 3D's if they send me email.

What is really neat about the 801 THRUST pdf is it shows the CG
position of the Lycoming engine. This is the best company to
work with I have found so far. Van's will not tell you anything :)

Paul Lamar


Paul
   On the subject of thrust line for the 801 there is no Dim from say the
top left and right bolt center to give you a exact Dim to the center of the
crank. How they measure it is from the top of the firewall to the center of
the crank. So you have to have a finished firewall so you can measure down
to find the location of the thrust line,not very exact.I went to the factory
open house in Oct. and came away more confused than informed. I wonder if
anyone has an exact Dim?

    Regards   Ed Klepeis