Mailing List flyrotary@lancaironline.net Message #36389
From: Tracy Crook <lors01@msn.com>
Subject: Re: American Rotary Engine / Call for help
Date: Sun, 1 Apr 2007 09:44:14 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>

Wow! What a ringing endorsement !  Thanks Lynn.

 

Product support is (or should be) a major factor in the choice of a lot of products.  In a market nitch as small as this one it takes on a whole new dimension.   I plan to be around for a long while but  companies as small as RWS can disappear overnight if the health or life of a single person goes away.  That is one reason I tried to make the RD-1 series gear drive as user serviceable as possible.  Most of the critical wear-prone parts can be bought from multiple sources and replaced by the end user.   Haven’t gotten around to that yet but I intend to compile a list of parts and sources and a service guide for the drives.

 

The same idea is not practical on things like the engine controllers and avionics products but I am trying to document all the products and processes used to make them well enough that the assets of the company would be attractive to a business buyer that could continue to build and support them.

Next, I need to ask for help (again) from the FlyRotary group.  It has been people here who have connected me with manufacturing resources needed to make this stuff and I’m hoping it might happen again.   Due to businesses closing down and others who have (I assume) gotten cold feet about being connected with anything to do with aircraft,  I will soon loose all three of my CNC machine shop suppliers.  I am amazed at how hard it is to find replacements.  The ones who have given quotes and built prototypes (including one of the biggest aftermarket automotive parts suppliers) have produced stuff that that I would not use in my kid’s soap box racer let alone an airplane (see attached photo of spline fit).  I’ve got lots of $500 paper weights sitting around the shop.

 

If you know of a good CNC machine shop supplier, please let me know.   The key capability is that they should be able to produce male splined shaft parts. 

 

The photo shows the fit of a recent prototype male spline part fit.  When I showed them this photo and pointed out the point contact at the tooth edges, the maker said not to worry, it would wear in and be fine!   OMG

 

Tracy

----- Original Message -----
Sent: Saturday, March 31, 2007 11:09 AM
Subject: [FlyRotary] Re: American Rotary Engine: Redrive
Patrick Panzera wrote:
>
>> What's the consensus on this?
>>
>> http://www.americanrotaryengine.com/id10.html
>>
>> Thanks!
>>
>> Pat
 
Well the 2.29:1 is a little tall for a rotary with over 70" of prop. But not real bad. 3056 prop RPM at 7,000 engine RPM,  2,838 Prop RPM at 6,500 engine RPM. 2,620 prop RPM at 6,000 engine RPM. 2,401 Prop RPM at 5,500 engine RPM.
 
It is a bit heavy.
 
The offset thrust line is of benefit for a longer prop. But then there is the ratio problem.
 
It is all custom parts, with only one source.
 
Adkins has a nice web site.
 
The price is a deal killer.
 
 
Tracy's reduction at 2.78:1 can swing a long prop or a three bladed prop for more ground clearance.
 
2,517 prop RPM at 7,000 engine RPM. 2,338 prop RPM at 6,500 prop RPM, 2,158 prop RPM at 6000 engine RPM, and 1,798 prop RPM at 5,500 engine RPM.
 
 
 
Tracy's system is lighter.
 
Tracy's system uses over the counter Ford parts.
 
Tracy's system has a zillion hours in the air, in a large number of airplanes.
 
The designer of Tracy's system (Tracy) is still alive and can be contacted via phone and Email.
 
You can sleep at Tracy's house for the fly-in.
 
Tracy will overhaul your Tracy redrive every year if you like.
 
Tracy's price is right.
 
Tracy's system is available now.
 
Tracy's system is available for other than rotary engines.
 
Tracy has a nice web site.
 
Tracy wins hands down.
 
 
Lynn E. Hanover
 
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