Paul,

   I have decided to go ahead and offer motor mount manufacturing. I
hesitated for a
moment as Chris seemed like a possible go also, despite his busy schedule.
I am in a
similar situation in that I was laid off last summer, but luckily for me
it meant about
30% as much work as before but now I get more than double the rate. This
also fits in
nicely with some other small things I'm looking to make and market ( if
only the
experimental market was as big as some other markets ). I plan to start
work on building a
jig this week and unless there is someone looking for a mount right away,
I'll start off
with one for my own aircraft if you wouldn't mind whipping one up for me.

   I down loaded the Qcad evaluation program and played with it for a
bit. Frankly I
think it sucks. Firstly it shuts down after ten minutes which is just a
nuisance and
secondly I don't find it in the least intuitive. I downloaded the Rhino
evaluation also
and played around with that too. I did have it on my old puter and some of
what I had
learned came back fairly quick. I think I'll be able to dimension and
angle from Rhino
quite effectively. It also reminded me how much I appreciate your adept
use of this tool
in the work you do for this group.

   My own aircraft is a Preceptor STOL King, I have an RWS drive and a JH
Schertz beam (
29" c to c ). The spacing on the mount points ( 5/16" bolts ) is 27 3/16"
horizontally and
18 13/16" vertically and the thrust line should be about 4" below the top
mount points.
Firewall to front of cowling is approximately 32 1/2". I'm not sure how
much further
forward the face of the prop flange should be, maybe 1/2" - 1" ? As TC's
box gives me
clockwise ( from pilots point of view ) rotation I think 2 degrees right
offset would be a
good idea.

   I have no idea how much a mount would cost but don't see why it
wouldn't be in line
with what Jerry was doing, and it seems he did a few. Hopefully he wasn't
giving them
away. The first one should give me a pretty good idea and I would
certainly make it work
on the first few mounts whilst I get all the bugs worked out. Any idea
from the list as to
how many mounts might be wanted would help, as would Jerry's rates. IIRC
Jerry did some
pretty complex mounts so I would expect the costs varied widely. Is Jerry
still on the list ?

John

"STOL King-Short Take Off & Land"
"Standard Engine: 75 HP 135 lb engine"
Are you planning on a two rotor John?
Are you perhaps building a one rotor?

I am happy to hear that you are planning on offering
motor mounts.

I am tooling up as we speak to make 50
rubber bushing holders. I have a friend with a robot welders so the
price on those should be reasonable.  Here is a picture.

No problem I can do a mount design for you but I am a bit
worried about installing a 2 rotor due to the weight.
Also the hard point mountings are a bit too close
for a 2 rotor.

Is the cowl made?
If so how long is it?
Total height of the firewall?
Position of the thrust line below
the top of the firewall?
How wide is the firewall?



The vast majority of the mounts are coming out about prop flange
to firewall dimension of 39".  Glad to hear you are getting Rhino up and
working as I have a vast collection motor mounts for different
aircraft done in Rhino.

Perhaps you were running Q cad on windows. On Linux it has
no such problems but of course 3D Rhino is head and shoulders
above any 2D cad program.


Paul Lamar

Planning on a one rotor, an O-200 would be 220# and 100hp, I figure a single
rotor p-port about the same but 125hp.
Some have been built in SA with O-320's but it kills the performance by
adding too much weight.

No cowl. The dimensions are determined by the tubing location at the front
of the fuselage which I am widening by 4".
There is no firewall shown in the plans, in fact there is nothing FWF at
all. The first page has the typically 3 perspective views and the builder is
on his own. From those views the firewall is very slightly oval 26 1/2" tall
and 31" wide (incl my 4").
Could you send an existing simple design that I can play with in Rhino ?

John

I will see what I can come up small enough to email.
Most of the native Rhino files are real big.

Paul Lamar

Paul, what are the 3D rhino file extensions, I would like to figure out what is compatible with Alibre Design.
I'm in for in for a pair of bushing holders and 4 mount pads if you have those made as well.
Thanks, C. Smith

The native Rhino file extensions for my version is 3dm but it does dxf, stp,
iges, stl to mention just the poplular ones. There are about a dozen others.
I have never heard of. What can Alibre import?

Paul Lamar