Our mini flyin in at Dietz Airpark Oregon went well.
 Philip Groelz and Steve BeckHam are restoring this old
 Power Sport prop dyno. Steve is building an RV3 air racer
 with long range tanks for the EAA 500 mile air race.

 Sitting around brain storming I had  the idea of starting
 a Wankel air race team and selling t-shirts to raise funds.
 Steve also has a large house with spare bedrooms and
 needs some expert help tig welding and machining.
 Steve has some nice machine tools and a large shop
 in a beautiful sitting on a private air strip.

 Paul Lamar

 Steve,

 Just to confirm.  Your club prop can only test at one load correct?  If
 you fly with a C/S prop isn't it better to test with different loads,
 rpms and MAPs?

 Doug in Japan

 Two loads :)

 Paul Lamar

The dyno came with a 32 inch diameter plywood disc which Everett and Steve
mounted on the protective cage to reduce inflow and test the engine under
different load conditions.

Philip


Hey that is a good idea. I saw that disk on these two pictures and
it never dawned on me what it's function was. Cheaper than making
a bunch of different size clubs or using a variable pitch prop.
Those guys are/were geniuses.

Paul Lamar

Paul,

OK that confirms something I have been suspecting, for years now.  The
prop load can be varied by the amount of  air it can suck.  Sort
partially blocking the  vaccumn cleaner hose.

This is one reason I opted for the engine in a wind tunnel tube concept.
The other reason is to test the assembled engine, monitoring equipment,
controller, cowl drag, cooling systems and wiring EXACTLY as it will be
flown.  One reason to have a built-in torque meter and an abundance of
sensors is that when the plane is actually  flying it is a flying dyno
adding flight performance data to the ground data.  Fewer surprises.


The the engine and mount is mounted on a metal frame and wheeled into  a
4 foot diameter wind tunnel from the rear.  The cowl will take up 70 %
of the cross sectional area and will create both a partial flow
restriction and an increase in wind velocity around it.  I hope to be
able to test at climb out speeds of 100 mph at least. The front inlet of
the tunnel transitions outwards to more than  72 inches in dia. to clear
the prop.

Depending on what system is being tested inlets or outlets can be
partially blocked, or some air can be bleed off of the tapered part
before reaching the tunnel proper.

Doug in Japan