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?

Paul Lamar


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