Paul,

I recently obtained a Renesis engine by going to Bruce Torringtin's
shop in
North Carolina and would like to install it on my highly
modified Variezy
which I am building. I have Tracy's B model PSRU and recently
have become
familiar with your web site.I noticed Gregg's mounting/adapter
plateand
have down loaded your instructions on designing a mount. Before
I do very
much I was wondering if you have already designed one for a Variezy.

Rolland LaPelle

We have something similar. I will change it to fit but
I need the exact dimensions on the firewall hard points
and the position of the thrust line relative to the
mount points. Can you scan the firewall dwgs and email
them to me? If you don't have a scanner you can zerox them
and mail that to me.

What kind of intake do you plan to use?

Paul Lamar

Rolland LaPelle wrote:
I found the drawings of the original Variezy but they dont
really show
the attachment very well so I made a quick sketch in auto cad 14 and
have attached it to this Email
to show the attaching point relationships that you requested.
Rolland

Please export that as a dxf file Rolland rather than a dwg.

Paul Lamar


Not Rolland, but here you go Paul.

Jarrett

Thanks Jarrett.
I hate to be the bearer of bad news Rolland but IMHO the motor mount
fixing in the Variezy are not up to the weight of a 2 rotor.
In addition there is no easy way to get the motor mount tubes
around the engine to where they are needed. At 14 inches or so the
fuselage is not quite wide enough. In addition the distance between
upper and lower hard point are going to drastically increase the
loads in the tubes at high G pull ups and hard landings.

My advice is build or find a Long EZ instead.

I also understand there is a problem with those aluminum
angles where they are bonded into the fiberglass. I know
of at least one case where they had to be replaced by
4130 steel. The Variez was designed for a Volkswagen engine.
Putting a O-200 in apparently over stressed the structure.

If you are still bound and determined to put a
rotary in regardless of the weight or you plan on using
aluminum end housing to lower the weight you could add
hard points to the top of the spar outboard of the
fuselage and use the landing gear bolts as lower
hard points.

Something like these 3Ds.


Paul Lamar


Putting O-320's (and sometimes O-360's) overstressed the mount design.
The mounts that were built properly didn't break.The LongEZ and
Cozy still used aluminum angles wrapped around spruce longerons.
Melville's O-360 powered LongEZ didn't break its mount in more than
2500 hours of operation.

I don't have a problem with substituting steel for aluminum here, but
I don't think the O-200 mount design was bad about cracking.I also
wonder if the smooth running rotary might be somewhat easier on the
mount..My impression is that vibration drives fatigue failures.

A separate but related topic is that Rutan did call out Max Take Off
Weight of 1110lbs and a max landing weight of 1050lbs for the VE.
Certainly they have been flown much heavier, but the low wing area of
the design leads to high minimum flying speeds.And that leads to
survivability problems if you have to put the airplane down
off-airport.Energy to dissipate in a crash is dominated by the V
squared term.With this mind, I agree that the LongEZ is a better
design for heavier engines.And bigger fuel tanks - the VE has 28 gal
and the LE has 52 gal.

One more point..The VW powered Varieze (N7EZ) had a smaller wing and
different airfoil than the Continental powered Varieze (N4EZ).I
can't put my finger on the difference in area, but it's mentioned in
the CP's.


Matt-

I said Variezy and not Long EZ broke. I have heard nothing
on the Long EZ version. As I recall there is more vertical
spread in the Long EZ which will drastically lower the loads.

They broke on Klaus's O-200.

Paul Lamar