> > >>> Wouldn't it be wonderful if everybody developing an engine for use
> > >>> in aircraft could afford a dyno. It would be a lot safer if people
> > >>> tested their intended engine for horsepower on the ground instead
of
> > >>> during the first flight. It would also verify or discredit some of
> > the
> > >>> claims made by vendors selling auto engines for aircraft use.
> > >>> All too frequently they claim xxx HP at 6500 RPM and then install
> > >>> a 1.4:1 PSRU.
> > >>>
> > >>>
http://www.youtube.com/watch?v=sImSPvPglbI
> > >>>
> > >>> The History Channel had a well done video segment on HP so
> > >>> I incorporated some of that. They asked a bunch of people; "What
> > >>> is HP?" and few could answer. It is amazing how many people
> > >>> still do not understand HP.
> > >>>
> > >>> There are good pictures of Ken Welters rotary powered Coot and
> > >>> Power Sports rotary engine prop dyno.
> > >>>
> > >>>
> > >>> Please give it the highest rating as that encourages other people
> > to view
> > >>> the video. The more rotary powered cars out there the better. This
> > >>> insures
> > >>> a future
> > >>> supply of the rotary engines, that we all know and love, for use
in
> > our
> > >>> aircraft.
> > >>> --
> > >>> Paul Lamar ...No rotor no motor.
> >
> > Paul, your suggestion regarding dyno testing rotary aircraft engines
> > with reduction gear installed would be a major advance for flight
safety.
> > This is the dyno we built in 1990 to test both rotary and Lycoming
> > engines. Phillip Groelz and I earlier discussed providing it for a
> > free/cost only testing service when people have fully assembled their
> > rotary engines. Would you be interested in being the dyno master if we
> > did this so there would be a good consolidated data base regarding
> > component development, service issues, sound, and performance?
> >
> > You may have seen the dyno when you were at the shop years ago. It
> > is basic and simple, using a torque arm connected to a rotary scale.
> > Uses the same principle as your drawing. We later added a pre-oiling
> > feature prior to startup. We discovered quickly that a shock absorber
> > for the torque arm was required for Lycomings due to the violent
shaking
> > on startup/shutdown. For rotary engine testing, heat exchangers were
> > installed along the back on top in the prop blast.
> >
> > The dyno instrumentation is old school so that would take two guys to
do
> > power runs....one to run it and the other to log the numbers during
> > runs. Be good to have modern data acquisition if possible
> > cost-wise. That area is your expertise. Phillip talked to Rob Hickman,
> > the owner/designer of Advance Flight Systems who lives next door and
> > would work with us. His system records the data. We talked to Rob
> > earlier about doing one for the rotary RV-3 being built and
considering
> > using it on the dyno to gather data. But if we were doing a lot of
> > engines we would want to have something dedicated to the dyno.
> >
> > One of the major design considerations would be noise containment
> > provisions because the shop/hangar is at an airpark. An advantage is
> > that guys could fly in. We are about 7 miles from Van's Aircraft at
> > Aurora.
> > If we did this, seems as though we would want to use a variant of your
> > S-beam mounts to take just all 2 rotor engines. Would take a separate
> > mount for three rotor engines to put test club in proper location in
> > shroud.
> >
---------------------------------------------------------------------------
> > Related background:
> > During the years we worked on the prototype rotary aircraft engines
> > using this dyno, it was stunning the number of things that broke
during
> > testing before the engine ever got into flight tests. We learned a lot
> > about what would crack or break--exhaust pipes and mufflers, accessory
> > mounting brackets , throttle shafts, oiling issues, ,engine mount
> > tubes,drive belt harmonics and on and on. Granted the issues we faced
> > were greater because these early prototypes engines used many
> > original components and combinations.
> >
> > Prior to constructing this dyno we ran the first Superlight rotary
> > aircraft engine in 1988 on the shop water brake dyno used for race car
> > and boat engines. Not good for the geared rotary engine because
> > without the propeller it did not provide the complete torsional
> > equation. Raised all kinds of hell with breaking input shafts,
> > reduction gear and pieces inside and outside the engine. The test
> > club shown here is the one we use for both Lycomings and rotary
> > engines. It started life as our first rotary engine propeller---84"
> > dia. and and high pitch. During early flight tests we lost a
> > stationary and internal rotor gear, and subsequently delaminated a tip
> > following the instant engine seizure. Cut down it maked a great test
> > club.
> >
----------------------------------------------------------------------------
-
> >
> > Steve Beckham
> >
> > Very interesting Steve. Thanks for sending that picture and background
> > info.
> >
> > Yes I think it is the same one in the second picture here that I took
in
> > your shop.
> > Your dyno inspired me to build mine.
> >
> > Did you ever try it back to back with and without the stator?
> >
> > Here at Santa Paula the sound is not an issue as we can tow our prop
dyno
> > mounted on a trailer out to the far reaches of the field and it makes
no
> > more noise than
> > a plane taking off. Also as long as you stay out of the plain of the
prop
> > a safety
> > shroud is unnecessary. No more dangerous than running up an aircraft
> > engine before takeoff.
> >
> > You guys were the pioneers. Now ten years later we have dozens of
aircraft
> > flying with
> > many many hours using either the Ross gear box or Tracy's gear box
with no
> > problems.
> > Some are using the latest six pinion Ford based auto tranny plantaries
on
> > three rotor engines.
> > The secret is the torque pulse isolators.
> >
> > Paul Lamar ...No rotor no motor.
> >
>
>
> Thanks Paul.
> As to your points--
>
> 1. Running the dyno with and without the stator?
> We ran the first engine on the dyno (a Lycoming) without the turning
vane
> assembly--had not built it and didn't know we needed it. But found the
prop
> blast exerted on the cylinders and evidently that long torque arm were
> obviously skewing the torque readings significantly and as I remember a
> significant improvement with cylinder cooling. Also the center blanking
> plate(s) were used to adjust prop load/ rpm range for various
engines--see
> photo--using same test club. This included the engine we built for Dan
> Denny's GlasAir III, a modified IO-540 . But if per your suggestion we
can
> make it work accurately without it, we should be able to test both 2,
3 or
> even 4 rotor engines all with your same modified mount.
>
> 2. The note about noise is driven as much as exhaust and combined
> exhaust/prop/gears. We found it necessary to do run, after run, after
run.
> Even with a muffler, the combined noise is a consideration in an
airpark.
> On engines tested before Mazda developed its port inserts, the noise
without
> mufflers was, as you can imagine, brutal. It was problematic even with
the
> low restriction mufflers we were using at the time. Neighbors for miles
> would complain--and this was when we tested at the shop down on the
farm.
> But I think this issue can be addressed. We could possibly keep the dyno
> down at the shop and test there but the logistics are a pain. And it
would
> be a disruption for Brent's operation there--he builds strictly
automotive
> and boats engines exception for some aircraft part component machining,
and
> balancing. And the airstrip has been allowed to deteriorate and closed.
>
> 3. Thanks for the photos of the rubber isolators. This is an approach
> similar to what we tested for our earliest planetary reduction drive. On
> subsequent planetary drive designs of various ratios using modified
> automotive gearsets we moved away from rubber isolators because we were
> shooting for something that would not be affected by heat, range of
motion,
> deterioration, cycling and ultimately were shooting for reduced parts
count.
> For gears, on the last SuperLight engine (see photo) we went away from
the
> Ford C-6 planetary-based parts used previously. On all the helical cut
> planetary gears, we found end-thrust a limiting factor for sustained
> high-output. Toasted end-thrust bearings. This problem was solved on the
> last planetary we did that is shown attached by incorporating straight
cut
> planets produced by Allison for truck applications (2.08:1). And by then
we
> had fully sorted out our pendulous dampers shown in this photo. It took
a
> lot of design and fabrication work over two years but really did the
job. A
> photo of it on dyno attached. Apologize for lousy quality. It's scanned
> off an old snapshop I took.
>
> 4.Ultimately we went away from the planetary reduction design because of
our
> decision to do the lower cost Iron Eagle Mazda conversion engine. To
reduce
> consumer costs the design goals included a simple, torsionally stiff
gearset
> without having to use any isolators, friction dampers, pendulous dampers
or
> anything and one that would hold up under repeated misfires....basically
> using the propeller as the flywheel. That's why we went to an internal
spur
> gear. The photo enclosed shows a view of the last SuperLight engine with
> planetary reduction gear and the Iron Eagle with the internal spur
reduction
> gear. When I sold Powersport it was with the desire that this SuperLight
> engine be donated to the EAA Museum. Hopfully it was not cannibalized
for
> parts. It was a neat piece and incorporated interesting stuff not known
to
> folks. It represented about 10 years of work. With the sale they also
> received our direct-drive, furnace brazed lightweight steel engine not
yet
> run.
>
> 5. Hope to see you at Marysville but it appears weather may be an issue
up
> here for mountains unless launch today.
>
> Steve Beckham
This video sparked a great deal of interest, as we are currently doing our
annual PMs on our dynos here at the advanced engineering center. Different
vendors have their own calibration method, some not so elegant. In looking
for a solution for a marginally thought out balance arm with dead weight
trays that walk side to side with each 50 lb addition, I was enlightened to
see the use of a "in house" instrument consisting of a manual screw jack and
a load cell coupled to an off the shelf display device. Probably $1K to
$1.5K in hardware. $500 just for the instruments. Looking into doing this
with all dead weight calibrations.
Anyway to ask a question, just exactly how does the electric absorber
balance the engine output? How does the load exactly follow the mechanical
power input? I see that it looks very much like an inverter motor drive, and
that we do return energy to the grid, but is it that part of the system that
returns power to the grid that makes the whole thing hard to follow?
C. Smith
You got me on all that. I can guess. When you decrease the resistance of the
load the generator has to work harder. How they decrease the resistance is the
big question. I am sure it can be done with todays solid state device but how
they did it when those old GM dynos were build is a major question in my mind.
Try googling "controlling the load on generators"
Paul Lamar ...No rotor no motor.
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