Rotary business

Hi, Paul....I wish to pick your brain for ideas. I am building an SQ2000 with a 13B. It would

be

very nice if I could start a small business using my aircraft and selling a rotary related
product, which I could fly to various fly-ins and promote such a product, similar to the way

Tracy

and others do. (I would like to incorporate the airplane into the business, and amortize it).

What

I am looking for, is a suggested product I might be able to produce and advertise on the

internet,

and show at various flyins that complement a 13B engine installation. I don't wish to get into
redrives,or installation manuals, or step on Tracy's feet.(He is already doing a fine job with

fine product) I also would pass on motor mounts, as Jerry Hey and others are going down that
path. I am looking for a project that I might be able to specialize in, and I thought, "who

better

to ask than the Mazda GURU, Paul Lamar"? I have some money to spend on development of the
product. Just looking for something that will be of use and possibly in demand. Thanks in

advance

for your thoughts/ideas. Paul Conner, Mobile, AL


Complete 321 SS & Inconel exhaust systems. Tried and true.
Start with the RV series. I'll make some engineering suggestions
as you move along. Build a test stand to test them before you risk
flying them.

Paul Lamar

I would be interested in a couple of other products that seem to be scarce. 1. Exhaust

augmentor.

This would be a natural in pusher applications like my LongEZ. It could provide plenty of

suction

for radiator airflow during taxi and low airspeeds and add a little additional thrust. If it is
possible to develop a multiple stage unit I think it would also quiet the exhaust. I understand
that current augmentors are quite loud.


2. A PSRU with a vertical offset. Tracy's RD1A looks like

an excellent unit but is a straight trough design. I am hoping to be able to drop my engine a
little lower while raising the prop about an inch. Ken Welter's belt drive has a reasonable

price

but I think the offset it too much and I don't know if he is too busy rebuilding his Coot to

build

PSRU's. I like the configuration of the Powersport unit that uses the internal ring gear with an
offset of about 3 inches, but the price is $6500. Ouch. If someone can come up with these

systems

at a reasonable price, I might be their first customer. I would even be willing to help test
prototypes since I will be doing my early flying within gliding distance of the home airport (D

Hooks in Houston), and the runways have landable farm land just beyond the runway ends. Dick
Gregory LongEZ N613NC

Dick, I think you will find any spur gear PSRU that provides offset not worth
the extra weight. It remains to be seen if any of them last as long as a Ford
six pinion planetary. The reason for this is a thing called gear line
contact length. Almost any planetary has much more gear line contact length
than any spur gear PSRU of reasonable size. The stresses are highest in the
gear line contact. The gear line contact length on a Ford six pinion is about
5.4 inches long in total. To get this in a spur gear transmission
results in a monster gear box. Here is a picture of such a spur
gear PSRU. This is out of an S51 and the box weighs over 120 pounds.
The line contact length is still only about three or four inches.

The vast majority of successful geared aircraft engines, and that
includes huge radial piston engines, almost all turbo props and some
turbo fan engines, use planetaries for that reason. The WW II liquid
cooled V engines are exceptions because they really need the off set.

We have ten of thousands of accumulative hours in 100's of Ross's
and Tracy's PSRU's.

Why do you need the offset?

Paul Lamar

In order to keep the prop axis the same as the
plans LEZ, the engine has to be mounted so high that parts of it are above the slope of the cowl.

The water pump, even a cut down version is still too high. The intake runners and the back of the
engine all sit proud of the original slope of the cowl, which is an extension of the slope from
the rear of the fuselage. I plan to move the alternator from the top down to the cool side, but I
wouldn't even have to do that if I drop the engine a bit. I wanted to raise my thrust line at
least an inch. The LongEZ was designed for 100-115 HP and I wanted to swing a larger diameter prop
without running into ground clearance problems. With the 13B and a Ross or RWS drive the prop
flange is farther back than the Lycoming installation which can mean problems during rotation and
flare.



I took a hard look at the belt drive configuration you have on your website. As far as I

know the only person making a similar setup is Ken Welter and I think that will give me too much
offset. I still need to keep room underneath for the rads. As it turns out, I will most likely go
ahead and use the RWS RD1A drive and work around what are probably relatively minor drawbacks for
my installation. Since his ratio is 2.17:1 I probably can't swing as large a prop as I would like
anyway, without the tips going sonic. I will get used to looking like a warthog. Maybe that's an
idea for a name for my airplane. Hmm. I always appreciate any feedback I get from you and the
other experienced engineers on the list. I always take experienced advice seriously and have
changed my planned approach many times based on this information. Thanks for all you do to help
those of us who are more technically challenged. Dick Gregory LongEZ N613NC


I think there are some Ross 2.85's out there for sale. Advantage
is it is about five or ten pounds lighter than Tracy's. There is also a short
version of the Ross as I recall.

Paul Lamar
 
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