Steve Hall wrote:
Does anyone have any experience with Conversion Concepts, Inc
Engine Mounts for a Canard?? Pro or Con.
Thanks,
Steve
http://conversionconcepts.com/cozymk-iv.htm
Nice pictures on the well done web site.
I am sure it will work but it needs some lateral bracing.
As it is now there is no lateral bracing and the tube
across the top where the mount fastens to the firewall
does nothing. There are other structural problems with
the mount. The two P51 type cantilevered tubing beams will
work but they need to be oriented in a vertical plain
instead of tilted in at the top. A 1/4 scale 3/16" stick
balsa model will immediately reveal these problems if
moderate loads are applied to the model.
Also the front motor mounts are going along for the ride
as the rear mounts (in a pusher) are carrying 95% of the load.
The sandwich motor plate idea has one of two serious drawbacks.
Either it is very heavy or it is very expensive to NC mill it out
like that. A solid 1/2 inch al plate 15" by 12" not counting
the ears would weigh 9 pounds if it were not milled out.
It cost several hundred dollars to mill it out. Not
including the cost of of the plate itself. At $3 a pound
it would be more than $36 including enough additional material
for the ears.
It could be replaced by a Schertz beam with $20 worth
of rectangular steel tubing. I don't know what the mount
cost but I have heard the number $800. Properly
designed without the motor plate the cost would be
way less than this.
Another problem it is prone to oil leaks. You have twice
the joint area for the oil to leak around the pan. The engine
is vibrating on top of the motor mount so there is likely
to be more movement in the joint between engine and motor plate.
Fred Breeze is an enigma to me. I think he has been on here
for years. As far as I know not once has he asked a question
or discussed motor mount design. I am amazed he has not educated
himself on space frame design long before this. There are plenty
of engineering text books on the subject. My favorite is Analysis
& Design of Flight Vehicle Structures by Braun.
Paul Lamar
The AirCraft Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/
Copyright 1998-2003 All world wide rights reserved.
Hi, Steve....regarding a motor mount from Conversion Concepts... I have
purchased one, so I wish to address your question. From a business
standpoint, I can attest that Fred delivers his product quickly. The
workmanship was excellent, the paint job was also very nice. The workmanship
in the plate that gets sandwiched between the engine and pan was also
outstanding. When I found a problem with the thrust line being a little
higher than I needed, Fred instructed me to send the mount back to him. He
made a new mount for me. No Charge. Tracy Crook is also using one of his
mounts.
There are of course other methods of mounting the rotary, as Paul
mentioned. I was swayed toward his mount because he made a custom mount for
me using my firewall attach dimensions, thrust line information and distance
from firewall to prop flange measurements for my SQ2000 canard pusher. It
bolted right up to my hard points on the firewall like it was made for it.
Come to think of it....it WAS made for it.
I had a couple other engineers look at the mount, and although they
thought it could be improved upon, they felt it would adequately do the job.
The Globe Swift uses a very similar motor mount. One feature that I like
about this mount is that I can easily remove the PSRU while leaving the
engine on the mount. Also, there is lots of room for a turbo if desired.
For me, it was nice to find someone that would make a mount to fit my
particular aircraft. Perry Mick had too many projects going, and Paul Lamar
asked if anyone else on the list was interested in making the mount for me.
No takers. Later on, a fellow named Jerry Hey started making motor mounts as
well. Unfortunately, the mount he proposed to me would attach to my PSRU,
which would not allow me to easily remove the PSRU for maintenance or
inspections. If you are good at welding, you can always make your own. For
me, I have too many other items to finish on my airplane instead of learning
how to weld and make motor mounts, so I am elated that we have people like
Fred Breese, Jerry Hey, Dave Atkins and Paul Lamar making items for our
rotaries to get them airborne sooner.( A constant speed prop is also in the
works. ) Without hairy chested rotary engine pioneers like these people, I
would be flying a Lycoming. For what it's worth. Paul Conner, 13B powered
SQ2000 almost finished.
Paul, I think you are wrong about being able to remove the PSRU from
the motor plate with the motor mounts on it. You just undo the 1/4 " bolts
instead of the long 10 mm bolts. To inspect the psru you must remove the 1/4"
bolts anyway. I have done it many times. Here is a pic with just
a couple of the 1/4" bolts holding the psru to the motor plate.
You don't necessarily have to use the motor plate for the mounts.
You can use a Schertz beam and motor plate and
all will come off with the engine still in the mount.
Paul Lamar
The AirCraft Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/
Copyright 1998-2003 All world wide rights reserved.
