[Todd TC. Carrico]
 > I wonder if you could use the side ports at idle,

and open up the PP at

 > full tilt boogie (this is a technical list is it not <g>).

The peripheral ported engine is more docile than the

bridge ported engine.

They will both idle below 1,000 RPM but do not sound

good doing it. It will

be shaking the daylights out of the stationary gears

and the gears in the

PSRU. The race cars idle at 1,800 to 2,000 RPM. You can

lean out the idle mix

and slow them way down, but
we run every system full rich and then some to get

enough fuel flow above

9,000 RPM. Our Booster venturies are cut off at the

bridge and we get very

little secondary signal. I suspect that adjustable

(Tracy's) fuel injection

would allow any idle speed you would want no matter

what ports you run.

Lynn E. Hanover

Idling an aircraft rotary engine at 2000 RPM is no

problem. Don't forget the

prop is turning only 922 RPM with a 2.17:1 gear box and

only 682 RPM

with Ken Welters 2.93:1 belt reduction drive. Heck I idle my
O-470 at 1000 prop RPM to keep the plugs from fouling.

I have seen Tracy idle his engine at 1000 RPM with no

gear box chatter.

That is because he uses rubber bushings to damp torque

fluctuations unlike the

Ross spring clutch center.

Paul Lamar

Paul,

It sounds like you've become accustomed to flying a constant
speed prop. High-pitched props=significant thrust at high
idle speeds. In an RV-x with a Lyc & fixed pitch prop, there
is a very noticable difference between 600 rpm & 800 rpm in
landing configuration. At 1000 prop rpm you've got a very
very flat glide slope.

Charlie England

It is true I fly a constant speed prop but I have also flown
my share of fixed
pitch props.

What you do is pitch up a bit until you get on the back side
of the power
curve (only done on final) and the sink rate goes back to
where it was. Practice
this a lot at altitude as it is quite dangerous if done
incorrectly. It helps
if you have a rate of climb instrument. Push the stick
slightly to decrease
the sink or give it a bit more power momentarily just before
touch down.
Then kill the engine by pulling the mixture. This operation
is just above
stall speed and in the category of mushing. It is below the x
axis on this
chart. A negative rate of climb.

Also slips will slow the plane on approach with a bit too
much RPM and a
fixed pitch prop. It is the best way as it take less skill.

BTW Tracy scares me a bit because he drags it in over the
tress at Shady Bend.
I would much prefer if he came in high and slipped it during
the last minutes.
Much safer in case of the engine quitting on short final. We
had a highly experienced
airline and air show pilot forced to land on the freeway at
Santa Paula because
he was using a conventional approach and the engine died on
final. Hit a car with
injures to the people in the car.

Do you have the Ross gear box Charlie? I think the Ross box
could be fixed
with a Tracy Crook style torsional isolator.

Paul Lamar

With the engine adjusted to idle at 1600 on the ground, I get around 2100
right before touchdown with the throttle closed because the fixed pitch prop
is still "reverse thrusting" against the engine. I have no trouble coming
down quick at that RPM. I can power it in behind the curve but it scares me,
too, I only do it for practice for if I only had 500 ft to land in.
I may be wrong but I think the Ross could be run at less than 1500 if needed
for approaches because reverse thrust keeps the backlash in the gears
meshed. Course you would still need to increase to 1600 or higher in the
rollout.

Chuck Dunlap
RV-6 13B

So Chuck what you are saying is the rotary is flying again. Are you flying it
to Sun & Fun? If you don't mind cruising at only 160 MPH with a 182 we can go 
in formation. We are stopping in Phoenix overnight on the way.

Paul Lamar
 
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